The guava plant has achieved viable significance in subtropics and tropics owing to its flexibility to climatic environments,soil conditions and higher human consumption.It is cultivated in vast areas of Asian and Non...The guava plant has achieved viable significance in subtropics and tropics owing to its flexibility to climatic environments,soil conditions and higher human consumption.It is cultivated in vast areas of Asian and Non-Asian countries,including Pakistan.The guava plant is vulnerable to diseases,specifically the leaves and fruit,which result in massive crop and profitability losses.The existing plant leaf disease detection techniques can detect only one disease from a leaf.However,a single leaf may contain symptoms of multiple diseases.This study has proposed a hybrid deep learning-based framework for the real-time detection of multiple diseases from a single guava leaf in several steps.Firstly,Guava Infected Patches Modified MobileNetV2 and U-Net(GIP-MU-NET)has been proposed to segment the infected guava patches.The proposed model consists of modified MobileNetv2 as an encoder,and the U-Net model’s up-sampling layers are used as a decoder part.Secondly,the Guava Leaf SegmentationModel(GLSM)is proposed to segment the healthy and infected leaves.In the final step,the Guava Multiple Leaf Diseases Detection(GMLDD)model based on the YOLOv5 model detects various diseases from a guava leaf.Two self-collected datasets(the Guava Patches Dataset and the Guava Leaf Diseases Dataset)are used for training and validation.The proposed method detected the various defects,including five distinct classes,i.e.,anthracnose,insect attack,nutrition deficiency,wilt,and healthy.On average,the GIP-MU-Net model achieved 92.41%accuracy,the GLSM gained 83.40%accuracy,whereas the proposed GMLDD technique achieved 73.3%precision,73.1%recall,71.0%mAP@0.5 and 50.3 mAP@0.5:0.95 scores for all the aforesaid classes.展开更多
Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films f...Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.展开更多
[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis （ Hen- del） ] in Nanning region of Guangxi Province. [ Method ] Using ...[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis （ Hen- del） ] in Nanning region of Guangxi Province. [ Method ] Using fixed system survey method, with fruit fly attractants as the materials, the occurrence dynamic of oriental fruit fly adult in guava orchard was investigated. The control effects of the methods such as fruit fly attractants, fruit bagging, cleaning park to pick up fallen fruit and timely spraying pesticide against the pest were also studied. [ Result] Oriental fruit fly had two damage peak periods in Nanning region of Guangxi Prov- ince （May to June, August to September）. Through the integrated control measures of trapping agent for male flies, timely spraying, fruit bagging and cleaning park to pick up fallen fruit, the population density in guava orchard dropped significantly. The fruit damage rates of guava in research base were only 6.67% -7.33% during the peak period of oriental fruit fly in June 2008, while they were 90.53% -98.00% in control area, obtaining good control effect against the pest. [ Con- dttalon ] The method used in the study preliminarily restored the yield losses of guava, which also provided basis for the preparation of overall strategy against orien- tal fruit fly in the region.展开更多
The global market of functional foods and demand for a healthy lifestyle among consumers in recent years is growing. Guava is a highly perishable fruit and a rich source of vitamin C. Guava Cheese (GC) is a semi-solid...The global market of functional foods and demand for a healthy lifestyle among consumers in recent years is growing. Guava is a highly perishable fruit and a rich source of vitamin C. Guava Cheese (GC) is a semi-solid concentrated fruit product that could be consumed as a snack. The objectives were to develop a guava cheese (GC) and determine the antioxidant potential of the product. Formulation consisted of guava puree with added sucrose or agave, chia seeds and almonds. Pectin was added at select concentrations (0.5%, 1%, 1.5%) along with citric acid to enhance the consistency of GC. Physiochemical and sensory parameters were analyzed for extended shelf life (3 months) studies. Moisture content, pH, water activity, color (L*, a*, b*) and texture profile analysis (hardness, springiness, cohesiveness, gumminess, chewiness) did not change over the 90-day period. Ash, protein and fat contents of 0% pectin were 2% lower than GC with pectin. Sensory parameters (firmness, mouthfeel, flavor and overall acceptability) of GC 0% pectin and 1% GC were similar. Total content in 0%, 0.5%, 1%, and 1.5% pectin added GC were 150.49 ± 32.76, 340.17 ± 54.65, 346.39 ± 53.04, and 355.72 ± 14.24 mg gallic acid equivalent (GAE)/100g. Flavonoid content in 0%, 0.5%, 1%, and 1.5% GC were 159.73 ± 13.31, 332.77 ± 13.31, 341.65 ± 15.37, and 350.52 ± 16.60 mg catechin equivalent (CE)/100g. Similarly, antioxidant of potential measure by DPPH radical scavenging was similar in all samples (IC50 at 0.8 mg/ml). Guava cheese may be utilized as a healthy fruit snack because of added alternative sweeteners and functional ingredients to obtain health benefits. Adding pectin to guava cheese improved functionality by increasing antioxidant potential as well as physical properties.展开更多
<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><...<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><span style="font-family:""><span style="font-family:Verdana;">, it is one of the leading causative agents of dental caries worldwide, because of its resistance to </span><span><span style="font-family:Verdana;">conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) chewing sticks on </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December</span></span><span style="font-family:Verdana;"> period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of</span><i><span style="font-family:Verdana;"> Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarind</span></i><span style="font-family:Verdana;"> (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) and </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">microbiological procedure w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants</span><span style="font-family:Verdana;">’</span><span style="font-family:""><span style="font-family:Verdana;"> extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> showed that the zones of inhibition recorded ranged from 18</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">mm to 27</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mm. Ethanol (Soxhlet) extract of I</span><span style="font-family:Verdana;">cheku twig showed no zone of inhibition on the isolated organism. The</span><span style="font-family:Verdana;"> ethanol (soxhlet) extract of the individual </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (Guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) twigs are made up of composite that </span></span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> active against </span><i><span style="font-family:Verdana;">S. mutans</span></i><span style="font-family:Verdana;"> and can be used in oral hygiene. There is </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria</span><span style="font-family:Verdana;">.展开更多
PBS (Phosphate Buffed Saline), pH 7.4 extract of Guava leaves (<i>Psidium</i> <i>guajava</i> L.) inhibits the active MMP-2 like molecule both of plant origin as well as active MMP-2 of human (b...PBS (Phosphate Buffed Saline), pH 7.4 extract of Guava leaves (<i>Psidium</i> <i>guajava</i> L.) inhibits the active MMP-2 like molecule both of plant origin as well as active MMP-2 of human (breast cancer patients’ saliva) origin. The zymogram and ELISA were developed of different samples following standard methods. The isolation and identification of the new MMP-2 inhibitor(s) for its molecular characterization is under investigation.展开更多
Guava (Psidium guajava L.), a tropical fruit, belongs to Myrtaceae family. Leaves and fruits of guava have been reported to have an anti-diarrheal, hypoglycemic, lipid lowering, anti-bacterial in addition to antioxida...Guava (Psidium guajava L.), a tropical fruit, belongs to Myrtaceae family. Leaves and fruits of guava have been reported to have an anti-diarrheal, hypoglycemic, lipid lowering, anti-bacterial in addition to antioxidant activities. The aim of this study was to investigate several guava leaf extract cytotoxic effects on healthy clone 9 liver cells and its hepatoprotective effects on ethanol-induced heap-toxicity. It was discovered that when the clone 9 liver cells were treated with guava (Psidium guajava Linn.) extracts for 24 hours, there was no retardation of growth as well as when ethanol and acetone extracts at low concentrations 100 μg/mL and 50 μg/mL were administered however cytototoxic effects were detected at higher concentrations. Water and hot water extracts in concentrations lower than or equal to 500 μg/mL revealed no cytotoxic effects. Injury induction to healthy clone 9 liver cells using 5% alcohol concentration for 30 minutes revealed the hepatoprotective properties of guava (Psidium guajava Linn.) extracts. This was significant in concentrations of 100 μg/mL or lower for ethanol and all concentrations for hot water extracts. Hot water extracts showed higher hepatoprotective and lower cytotoxic properties than other extracts.展开更多
Guava is one of the most important fruits in Pakistan,and is gradually boosting the economy of Pakistan.Guava production can be interrupted due to different diseases,such as anthracnose,algal spot,fruit fly,styler end...Guava is one of the most important fruits in Pakistan,and is gradually boosting the economy of Pakistan.Guava production can be interrupted due to different diseases,such as anthracnose,algal spot,fruit fly,styler end rot and canker.These diseases are usually detected and identified by visual observation,thus automatic detection is required to assist formers.In this research,a new technique was created to detect guava plant diseases using image processing techniques and computer vision.An automated system is developed to support farmers to identify major diseases in guava.We collected healthy and unhealthy images of different guava diseases from the field.Then image labeling was done with the help of an expert to differentiate between healthy and unhealthy fruit.The local binary pattern(LBP)was used for the extraction of features,and principal component analysis(PCA)was used for dimensionality reduction.Disease classification was carried out using multiple classifiers,including cubic support vector machine,Fine K-nearest neighbor(F-KNN),Bagged Tree and RUSBoosted Tree algorithms and achieved 100%accuracy for the diagnosis of fruit flies disease using Bagged Tree.However,the findings indicated that cubic support vector machines(C-SVM)was the best classifier for all guava disease mentioned in the dataset.展开更多
Frequent consumption of fruits and vegetables has been associated with low risk of chronic diseases. Guava (Psidium guajava Linn.) is a tropical, seasonal fruit rich in antioxidants, vitamin C and polyphenol compounds...Frequent consumption of fruits and vegetables has been associated with low risk of chronic diseases. Guava (Psidium guajava Linn.) is a tropical, seasonal fruit rich in antioxidants, vitamin C and polyphenol compounds. Drying is one of the common methods to preserve and extend the shelf life of guava. The objective of this study was to determine the effect of drying techniques on the antioxidant activity of guava fruit. Guava was air dried in air dryer (45°C), freeze dryer and by osmatic drying techniques. Fresh guava extracts (FGE), freeze dried guava extracts (FDGE), oven dried guava extracts (ODGE) and osmotic-dehydrated guava extracts (OSGE) guava extracts were prepared and analyzed for total polyphenols (TP), flavonoids, antioxidant potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), total antioxidant capacity (TAC) and nitric oxide radical scavenging activity (NORS). Inhibitory potential of guava extracts on enzymes α-glucosidase, α-amylase and lipase was also determined. TP in FG, FD, OD, and OS were 415.69 ± 56.95, 295.30 ± 4.11, 303.57 ± 1.41, and 182.93 ± 6.48 mg gallic acid equivalent (GAE)/100g, respectively. Flavonoids in Fresh, FD, OD, and OS were 202.01 ± 0.16, 96.93 ± 1.73, 105.07 ± 0.58, and 76.13 ± 2.74 mg catechin equivalent (CE)/100 g, respectively. FD extracts were the most effective in scavenging DPPH radical. Whereas FRAP, TEAC and TAC activities were found to be higher in FG followed by OD and FD. However, NORS activity of FD was significantly (p ≤ 0.05) lower compared to other treatments. Inhibition of α-glycosidase, α-amylase and lipase enzymes was (19% - 90%) observed at 0.4, 0.8, and 0.8 mg/ml, respectively. In conclusion, considering this in-vitro study, drying could be effectively utilized to preserve guava fruit with minimum effect on health benefits.展开更多
Red and white guavas were treated with wax emulsion or irradiation (0.25-2.0 kGy) and kept for 12 days at room temperature. Initiation of rot attack occurred after 3 days which increased significantly during further s...Red and white guavas were treated with wax emulsion or irradiation (0.25-2.0 kGy) and kept for 12 days at room temperature. Initiation of rot attack occurred after 3 days which increased significantly during further storage. In the waxed fruits rottage, weight loss and vitamin loss were significantly less than controls and irradiated ones. Sensory scores decreased with storage time and they ranged 3.7-4.5, 2.1-3.9 and 2.3-2.7 in waxed, radiated and untreated controls respectively, after 12 days storage. Waxing was found to increase the. shelf life of this fruit for 3-4 d while irradiation exhibited no beneficial effects.展开更多
A non-destructive method for assessing the maturity of guava was developed based on the mechanical properties of the fruit under the slight falling impact test. The levels of maturity were classified with cluster and ...A non-destructive method for assessing the maturity of guava was developed based on the mechanical properties of the fruit under the slight falling impact test. The levels of maturity were classified with cluster and discriminant analyses on the primitive impact measurements and their derivatives. The accuracy of classification was improved with linear discriminant analysis and the number of indices being processed was reduced with stepwise regression analysis. The accuracy of classification is 84.21%. The performance shows that slight falling impact together with linear discriminant analysis provides a promising non-destructive approach in assessing the maturity of guavas.展开更多
The leaf of Psidium guava is traditionally used in Asia to manage, control and treat diabetes. We designed this study to elucidate the effect of the administration of oral doses of aqueous and ethanol extract from Psi...The leaf of Psidium guava is traditionally used in Asia to manage, control and treat diabetes. We designed this study to elucidate the effect of the administration of oral doses of aqueous and ethanol extract from Psidium guava leaves on plasma glucose, lipid profiles and the sensitivity of the vascular mesenteric bed to Phenylephrine in diabetic and non diabetic rats. Animals were divided into 5 groups (n = 10): two groups served as non-diabetic controls (NDC), while the other groups had diabetes induced with a single injection of streptozotocin (STZ). Psidium guava-treated chronic diabetic (PSG-CD) and Psidium guava-treated controls (PSG-C) received 1g/l of Psidium guavaadded to the drinking water for 8 weeks. The mesenteric vascular beds were prepared using the McGregor method. Administration of Psidium guava caused Ca/Mg ratio, plasma glucose, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), total cholesterol and triglyceride concentrations to return to normal levels, and was shown to decrease alteration in vascular reactivity to vasoconstrictor agents. Our results support the hypothesis that Psidium guava could play a role in the management of diabetes and the prevention of vascular complications in STZ-induced diabetic rats.展开更多
A study conducted on burgundy rabbits evaluated the effects of rations containing mango (Mangifera indica), avocado (Persea americana) and guava (Psidium guajava) powder. For this purpose, 36 rabbits (20 males and 16 ...A study conducted on burgundy rabbits evaluated the effects of rations containing mango (Mangifera indica), avocado (Persea americana) and guava (Psidium guajava) powder. For this purpose, 36 rabbits (20 males and 16 females) aged 60 to 70 days with an average weight of 1012 ± 133 g were divided randomly into 4 equal groups (T0, T1, T2 and T3) of 9 animals each according to body weight (bw). The rabbits were divided throughout the trial, the animals were fed, those of group T0 (control) with a standard feed without any type of leaf powder, while those of groups 1, 2 and 3 received the standard feed supplemented with Mangifera indica, Persea americana and Psidium guajava leaves powder at the rate of 0.5% respectively. After two months of treatment, the animals were fasted for 12 hours (20 h - 8 h) and sacrificed to evaluate carcass and digestive organ weights. The results revealed that the values of feed intake, live weight and weight gain were non-significantly (p > 0.05) increased in all animals regardless of the ration in reference to the control. The different leaves powder induced an increase in carcass yield in rabbits but this increase was only significant (p M. indica leaf powder (51.03 ± 0.24) as compared to the control (48.63 ± 0.74). Gut length was significantly increased in animals fed rations containing Psidium guajava and Persea americana leaves powder compared to the control. A significant increase in gut weight was observed in animals fed the Persea americana leaf supplemented ration. In general, mango leaf powder performed better than other types of powders.展开更多
Detection of the presence of Anastrepha striata and Anastrepha ludens in guava cultures is presently done in Mexico by actually catching the flies in strategically located traps. The objective of this study is to show...Detection of the presence of Anastrepha striata and Anastrepha ludens in guava cultures is presently done in Mexico by actually catching the flies in strategically located traps. The objective of this study is to show that it is possible to locate areas with the presence or absence of flies by remote sensing means, thereby simplifying the traditional way of detection of these plagues. In the field, groups of traps were selected where flies had been captured, as well as areas in which there was no capture in the traps. The radiometric signatures of whole trees and leaves were obtained, showing measurable differences between those specimens affected by the plague and those unaffected. Next we selected a SPOT5 image of 2007 corresponding to the study area in Calvillo, State of Aguascalientes, in Mexico, one of the major areas of guava cultures in the country. A supervised classification of the image allowed for the location of guava cultures in it. The guava culture areas obtained from this classification were validated comparing them to available maps of the cultured areas. Spectral signatures for the classes were derived from the image data. The separability of pairs of classes was also evaluated in order to maximize it. The IR/R （infrared to red ratio） ratio of the image bands was evaluated in 80 × 80 pixels around the locations of five traps where flies had been captured, and around five locations where the traps had not captured flies. Only the pixels where guava cultures were present were included in the analysis, other types of vegetation and soil coverage were rejected. We found that the index distributions with flies captured and those without flies captured cluster in two well-separated groups. We note that plotting the whole distribution of pixels around a trap yields a diagnostic view of the area, and individual index values do not provide such a view, since values with the flies＇ presence and without these overlap to some extent. Further analyses of other trap locations confirmed this separation and also revealed a third group of intermediate values between the two above, that are interpreted as locations in which the guava cultures are affected by the plague at an early stage of development, where the flies are not captured by the traps since they do not yet hatch. We concluded that it is possible to use remote sensing techniques to identify the presence ofAnastrepha striata and Anastrepha ludens in cultures of Psidium guajava L., even probably at early stages of development of the plague.展开更多
The leaf-response to three-soil applied treatments of Paclobutrazol (PBZ;1000, 2000 and 0 ppm-control) was studied in a high-density plantation of eight guava (Psidium guajava) genotypes trees. All materials were prun...The leaf-response to three-soil applied treatments of Paclobutrazol (PBZ;1000, 2000 and 0 ppm-control) was studied in a high-density plantation of eight guava (Psidium guajava) genotypes trees. All materials were prunned in vase form, with two to three major branches, yearly prunning for triggering the annual production cycle, and average height of 2.0 m. The dataset comprises fourth radiometric indices highly related to plant physiological activities. The dataset model took into account data collection dates, guava genotypes, and the positional effect of sun radiation on leaves based on their proximity to the canopy level and downward to the base of the woody seasonal-branch. Unexpectedly, there were no significant differences (NS) in PBZ treatments for genotypes, leaf position and radiometric indices. Analysis of the radiometric indices data revealed that anthocyanin (ARI index) and chlorophyll (PRI index) have a strong inverse relationship. Significant differences (P ≤ 0.05) were found between guava genotypes, and anthocyanin content;these results show that guava genotypes have varied responses, which could derive in their classification based-on drought resistance or low water requirements, however, it is important to note that additional research is required to determine the scope of these indications.展开更多
Field studies were carried out during kharif 2016 and summer 2017 at Udyanagiri,UHS,Bagalkot,Karnataka,India to evaluate IPM modules against fruit fly in an already established guava orchard of variety Sardar(L-49).Am...Field studies were carried out during kharif 2016 and summer 2017 at Udyanagiri,UHS,Bagalkot,Karnataka,India to evaluate IPM modules against fruit fly in an already established guava orchard of variety Sardar(L-49).Among four modules,the mean fruit damage was significantly the lowest in M3(0.68%)followed by M2(1.19%)and M1(2.21%)and were on par with each other during kharif 2016.During summer 2017,M3 recorded significantly lowest damage(0.59%)followed by M2(0.92%)and M1(2.41%)but were on with each other.The highest per cent protection was afforded by M3(95.76 and 96.76,respectively)during 2016 and 2017.The average fruit yield over the years of experimentation revealed significantly the highest fruit yield(8.13 t/ha)from M3 followed by M2(7.32 t/ha)and M1(5.31 t/ha).Among the four modules,highest B:C was from M3(7.65)followed by M2(6.67)and M1(4.91).展开更多
Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypogl...Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B （protein tyrosine phosphatase 1b） was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.展开更多
Objective: To observe the clinical effect of guava leaf (GL) in treating infantile rotaviral enteritis.Methods: Sixty-two patients of rotaviral enteritis were randomly divided into the treated group treated with GL an...Objective: To observe the clinical effect of guava leaf (GL) in treating infantile rotaviral enteritis.Methods: Sixty-two patients of rotaviral enteritis were randomly divided into the treated group treated with GL and the control group treated with Gegen Qinlian Decoction. The time for ceasing diarrhea, content of Na+ in blood, content of Na+ and glucose in stool, and the rate of negative conversion of human rotavirus antigen (HRVA) were observed.Results: The 3-day recovery rate in the treated group (87.1%) was significantly higher than that in the control group (58.1%, P<0.05). The time of ceasing diarrhea in the treated group (25.1±9.5 hrs) was significantly shorter than that in the control group (38.7±15.2 hrs, P<0.01). Moreover, content of Na+ and glucose in stool were reduced obviously in the treated group but not in the control group; and negative conversion rate of HRVA in the former group also got better than that in the latter group (87.1% vs 58.1%, P<0.05). Consequently, the effect of GL was superior to that of the control significantly.Conclusion: GL has good curative effect on infantile rotaviral enteritis.展开更多
基金financially supported by the Deanship of Scientific Research,Qassim University,Saudi Arabia for funding the publication of this project.
文摘The guava plant has achieved viable significance in subtropics and tropics owing to its flexibility to climatic environments,soil conditions and higher human consumption.It is cultivated in vast areas of Asian and Non-Asian countries,including Pakistan.The guava plant is vulnerable to diseases,specifically the leaves and fruit,which result in massive crop and profitability losses.The existing plant leaf disease detection techniques can detect only one disease from a leaf.However,a single leaf may contain symptoms of multiple diseases.This study has proposed a hybrid deep learning-based framework for the real-time detection of multiple diseases from a single guava leaf in several steps.Firstly,Guava Infected Patches Modified MobileNetV2 and U-Net(GIP-MU-NET)has been proposed to segment the infected guava patches.The proposed model consists of modified MobileNetv2 as an encoder,and the U-Net model’s up-sampling layers are used as a decoder part.Secondly,the Guava Leaf SegmentationModel(GLSM)is proposed to segment the healthy and infected leaves.In the final step,the Guava Multiple Leaf Diseases Detection(GMLDD)model based on the YOLOv5 model detects various diseases from a guava leaf.Two self-collected datasets(the Guava Patches Dataset and the Guava Leaf Diseases Dataset)are used for training and validation.The proposed method detected the various defects,including five distinct classes,i.e.,anthracnose,insect attack,nutrition deficiency,wilt,and healthy.On average,the GIP-MU-Net model achieved 92.41%accuracy,the GLSM gained 83.40%accuracy,whereas the proposed GMLDD technique achieved 73.3%precision,73.1%recall,71.0%mAP@0.5 and 50.3 mAP@0.5:0.95 scores for all the aforesaid classes.
基金funding from the Environmental Science Program for Academic Excellence and Community Research for Fiscal Year 2024,a financial resource of the Environmental Science and Technology Program,Faculty of Science,Buriram Rajabhat University.Additionally,Buriram Rajabhat University provided a publication budget.
文摘Polymeric materials,known for their lightweight and strength,are widely used today.However,their non-biodegradable nature poses significant environmental challenges.This research aimed to develop biodegradable films from fruits and vegetables,using alginate as a binding agent.Using a completely randomized design,seven experimental sets were prepared with carrots,Kimju guava,and Namwa banana peel fibers as the primary materials and alginate as the secondary material at three levels:1.2,1.8,and 2.4 by weight.The solution technique was employed to create the samples.Upon testing mechanical and physical properties,experimental set 3,consisting of 60%guava and 1.8%alginate,emerged as the optimal ratio.This combination exhibited favorable physical properties,including a thickness of 0.26±0.02 mm,meeting the standards for food packaging films.Additionally,the tensile strength was 0.50±0.01 N/m²,and the elongation at break was 55.60±0.44%.Regarding chemical properties,the moisture content of 5.64±0.03%fell within the acceptable range for dried food.Furthermore,a 30-day soil burial test revealed that the sample from experimental set 3 exhibited the highest degradation rate.In conclusion,these findings suggest that guava can be a promising raw material for producing biodegradable plastics suitable for packaging applications.
基金Supported by Educational Commission of Guangxi Province of China (GJR(2007)No.70)~~
文摘[ Objective ] The paper was to explore the damage, occurrence pattern and integrated control methods of oriental fruit fly [ Bactrocera dorsalis （ Hen- del） ] in Nanning region of Guangxi Province. [ Method ] Using fixed system survey method, with fruit fly attractants as the materials, the occurrence dynamic of oriental fruit fly adult in guava orchard was investigated. The control effects of the methods such as fruit fly attractants, fruit bagging, cleaning park to pick up fallen fruit and timely spraying pesticide against the pest were also studied. [ Result] Oriental fruit fly had two damage peak periods in Nanning region of Guangxi Prov- ince （May to June, August to September）. Through the integrated control measures of trapping agent for male flies, timely spraying, fruit bagging and cleaning park to pick up fallen fruit, the population density in guava orchard dropped significantly. The fruit damage rates of guava in research base were only 6.67% -7.33% during the peak period of oriental fruit fly in June 2008, while they were 90.53% -98.00% in control area, obtaining good control effect against the pest. [ Con- dttalon ] The method used in the study preliminarily restored the yield losses of guava, which also provided basis for the preparation of overall strategy against orien- tal fruit fly in the region.
文摘The global market of functional foods and demand for a healthy lifestyle among consumers in recent years is growing. Guava is a highly perishable fruit and a rich source of vitamin C. Guava Cheese (GC) is a semi-solid concentrated fruit product that could be consumed as a snack. The objectives were to develop a guava cheese (GC) and determine the antioxidant potential of the product. Formulation consisted of guava puree with added sucrose or agave, chia seeds and almonds. Pectin was added at select concentrations (0.5%, 1%, 1.5%) along with citric acid to enhance the consistency of GC. Physiochemical and sensory parameters were analyzed for extended shelf life (3 months) studies. Moisture content, pH, water activity, color (L*, a*, b*) and texture profile analysis (hardness, springiness, cohesiveness, gumminess, chewiness) did not change over the 90-day period. Ash, protein and fat contents of 0% pectin were 2% lower than GC with pectin. Sensory parameters (firmness, mouthfeel, flavor and overall acceptability) of GC 0% pectin and 1% GC were similar. Total content in 0%, 0.5%, 1%, and 1.5% pectin added GC were 150.49 ± 32.76, 340.17 ± 54.65, 346.39 ± 53.04, and 355.72 ± 14.24 mg gallic acid equivalent (GAE)/100g. Flavonoid content in 0%, 0.5%, 1%, and 1.5% GC were 159.73 ± 13.31, 332.77 ± 13.31, 341.65 ± 15.37, and 350.52 ± 16.60 mg catechin equivalent (CE)/100g. Similarly, antioxidant of potential measure by DPPH radical scavenging was similar in all samples (IC50 at 0.8 mg/ml). Guava cheese may be utilized as a healthy fruit snack because of added alternative sweeteners and functional ingredients to obtain health benefits. Adding pectin to guava cheese improved functionality by increasing antioxidant potential as well as physical properties.
文摘<span style="font-family:Verdana;">Globally dental diseases are mainly caused by</span><i><span style="font-family:Verdana;"> Streptococcus mutans</span></i><span style="font-family:""><span style="font-family:Verdana;">, it is one of the leading causative agents of dental caries worldwide, because of its resistance to </span><span><span style="font-family:Verdana;">conventional antibacterial agents, alternative therapies are used to control resistance of oral pathogens. This research was done to determine the antibacterial activities of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) chewing sticks on </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> isolated from the oral cavity. The study was conducted in Owerri Imo State Nigeria during November-December</span></span><span style="font-family:Verdana;"> period. Phytochemical analysis of the plant extracts was done using appropriate techniques. The procedure used for antimicrobial susceptibility test was disk diffusion method. Serial dilutions of</span><i><span style="font-family:Verdana;"> Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarind</span></i><span style="font-family:Verdana;"> (Icheku) extracts were prepared, Muller-Hinton media was used to put together the extract of serial dilutions of </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) and </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">microbiological procedure w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> used for visually determining the minimum inhibitory concentration as well as minimum bactericidal concentration. Phytochemical evaluation of the plants</span><span style="font-family:Verdana;">’</span><span style="font-family:""><span style="font-family:Verdana;"> extracts revealed that it contains saponins, tannins, alkaloid, steriods, glycosides and phenol. The results obtained from the antibacterial susceptibility testing of the extracts against </span><i><span style="font-family:Verdana;">Streptococcus mutans</span></i><span style="font-family:Verdana;"> showed that the zones of inhibition recorded ranged from 18</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">mm to 27</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">mm. Ethanol (Soxhlet) extract of I</span><span style="font-family:Verdana;">cheku twig showed no zone of inhibition on the isolated organism. The</span><span style="font-family:Verdana;"> ethanol (soxhlet) extract of the individual </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) has a better antibacterial effect when compared to their aqueous extracts and combined forms. </span><i><span style="font-family:Verdana;">Psidium guajava</span></i><span style="font-family:Verdana;"> (Guava) and </span><i><span style="font-family:Verdana;">Velvet tamarin</span></i><span style="font-family:Verdana;"> (Icheku) twigs are made up of composite that </span></span><span style="font-family:Verdana;">is</span><span style="font-family:""><span style="font-family:Verdana;"> active against </span><i><span style="font-family:Verdana;">S. mutans</span></i><span style="font-family:Verdana;"> and can be used in oral hygiene. There is </span></span><span style="font-family:Verdana;">a </span><span style="font-family:Verdana;">need for further investigation on the plant extracts as the rural poor make use of it because it is cheap, readily available and the rich also use it once they are in the village mostly in Eastern Nigeria. Similarly chewing sticks has been reported to be practiced by 90 of rural population in Nigeria</span><span style="font-family:Verdana;">.
文摘PBS (Phosphate Buffed Saline), pH 7.4 extract of Guava leaves (<i>Psidium</i> <i>guajava</i> L.) inhibits the active MMP-2 like molecule both of plant origin as well as active MMP-2 of human (breast cancer patients’ saliva) origin. The zymogram and ELISA were developed of different samples following standard methods. The isolation and identification of the new MMP-2 inhibitor(s) for its molecular characterization is under investigation.
文摘Guava (Psidium guajava L.), a tropical fruit, belongs to Myrtaceae family. Leaves and fruits of guava have been reported to have an anti-diarrheal, hypoglycemic, lipid lowering, anti-bacterial in addition to antioxidant activities. The aim of this study was to investigate several guava leaf extract cytotoxic effects on healthy clone 9 liver cells and its hepatoprotective effects on ethanol-induced heap-toxicity. It was discovered that when the clone 9 liver cells were treated with guava (Psidium guajava Linn.) extracts for 24 hours, there was no retardation of growth as well as when ethanol and acetone extracts at low concentrations 100 μg/mL and 50 μg/mL were administered however cytototoxic effects were detected at higher concentrations. Water and hot water extracts in concentrations lower than or equal to 500 μg/mL revealed no cytotoxic effects. Injury induction to healthy clone 9 liver cells using 5% alcohol concentration for 30 minutes revealed the hepatoprotective properties of guava (Psidium guajava Linn.) extracts. This was significant in concentrations of 100 μg/mL or lower for ethanol and all concentrations for hot water extracts. Hot water extracts showed higher hepatoprotective and lower cytotoxic properties than other extracts.
基金This work is supported by the Deanship of Scientific Research at King Saud University through research Group No.RG-1441-379.
文摘Guava is one of the most important fruits in Pakistan,and is gradually boosting the economy of Pakistan.Guava production can be interrupted due to different diseases,such as anthracnose,algal spot,fruit fly,styler end rot and canker.These diseases are usually detected and identified by visual observation,thus automatic detection is required to assist formers.In this research,a new technique was created to detect guava plant diseases using image processing techniques and computer vision.An automated system is developed to support farmers to identify major diseases in guava.We collected healthy and unhealthy images of different guava diseases from the field.Then image labeling was done with the help of an expert to differentiate between healthy and unhealthy fruit.The local binary pattern(LBP)was used for the extraction of features,and principal component analysis(PCA)was used for dimensionality reduction.Disease classification was carried out using multiple classifiers,including cubic support vector machine,Fine K-nearest neighbor(F-KNN),Bagged Tree and RUSBoosted Tree algorithms and achieved 100%accuracy for the diagnosis of fruit flies disease using Bagged Tree.However,the findings indicated that cubic support vector machines(C-SVM)was the best classifier for all guava disease mentioned in the dataset.
文摘Frequent consumption of fruits and vegetables has been associated with low risk of chronic diseases. Guava (Psidium guajava Linn.) is a tropical, seasonal fruit rich in antioxidants, vitamin C and polyphenol compounds. Drying is one of the common methods to preserve and extend the shelf life of guava. The objective of this study was to determine the effect of drying techniques on the antioxidant activity of guava fruit. Guava was air dried in air dryer (45°C), freeze dryer and by osmatic drying techniques. Fresh guava extracts (FGE), freeze dried guava extracts (FDGE), oven dried guava extracts (ODGE) and osmotic-dehydrated guava extracts (OSGE) guava extracts were prepared and analyzed for total polyphenols (TP), flavonoids, antioxidant potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), total antioxidant capacity (TAC) and nitric oxide radical scavenging activity (NORS). Inhibitory potential of guava extracts on enzymes α-glucosidase, α-amylase and lipase was also determined. TP in FG, FD, OD, and OS were 415.69 ± 56.95, 295.30 ± 4.11, 303.57 ± 1.41, and 182.93 ± 6.48 mg gallic acid equivalent (GAE)/100g, respectively. Flavonoids in Fresh, FD, OD, and OS were 202.01 ± 0.16, 96.93 ± 1.73, 105.07 ± 0.58, and 76.13 ± 2.74 mg catechin equivalent (CE)/100 g, respectively. FD extracts were the most effective in scavenging DPPH radical. Whereas FRAP, TEAC and TAC activities were found to be higher in FG followed by OD and FD. However, NORS activity of FD was significantly (p ≤ 0.05) lower compared to other treatments. Inhibition of α-glycosidase, α-amylase and lipase enzymes was (19% - 90%) observed at 0.4, 0.8, and 0.8 mg/ml, respectively. In conclusion, considering this in-vitro study, drying could be effectively utilized to preserve guava fruit with minimum effect on health benefits.
文摘Red and white guavas were treated with wax emulsion or irradiation (0.25-2.0 kGy) and kept for 12 days at room temperature. Initiation of rot attack occurred after 3 days which increased significantly during further storage. In the waxed fruits rottage, weight loss and vitamin loss were significantly less than controls and irradiated ones. Sensory scores decreased with storage time and they ranged 3.7-4.5, 2.1-3.9 and 2.3-2.7 in waxed, radiated and untreated controls respectively, after 12 days storage. Waxing was found to increase the. shelf life of this fruit for 3-4 d while irradiation exhibited no beneficial effects.
文摘A non-destructive method for assessing the maturity of guava was developed based on the mechanical properties of the fruit under the slight falling impact test. The levels of maturity were classified with cluster and discriminant analyses on the primitive impact measurements and their derivatives. The accuracy of classification was improved with linear discriminant analysis and the number of indices being processed was reduced with stepwise regression analysis. The accuracy of classification is 84.21%. The performance shows that slight falling impact together with linear discriminant analysis provides a promising non-destructive approach in assessing the maturity of guavas.
文摘The leaf of Psidium guava is traditionally used in Asia to manage, control and treat diabetes. We designed this study to elucidate the effect of the administration of oral doses of aqueous and ethanol extract from Psidium guava leaves on plasma glucose, lipid profiles and the sensitivity of the vascular mesenteric bed to Phenylephrine in diabetic and non diabetic rats. Animals were divided into 5 groups (n = 10): two groups served as non-diabetic controls (NDC), while the other groups had diabetes induced with a single injection of streptozotocin (STZ). Psidium guava-treated chronic diabetic (PSG-CD) and Psidium guava-treated controls (PSG-C) received 1g/l of Psidium guavaadded to the drinking water for 8 weeks. The mesenteric vascular beds were prepared using the McGregor method. Administration of Psidium guava caused Ca/Mg ratio, plasma glucose, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), total cholesterol and triglyceride concentrations to return to normal levels, and was shown to decrease alteration in vascular reactivity to vasoconstrictor agents. Our results support the hypothesis that Psidium guava could play a role in the management of diabetes and the prevention of vascular complications in STZ-induced diabetic rats.
文摘A study conducted on burgundy rabbits evaluated the effects of rations containing mango (Mangifera indica), avocado (Persea americana) and guava (Psidium guajava) powder. For this purpose, 36 rabbits (20 males and 16 females) aged 60 to 70 days with an average weight of 1012 ± 133 g were divided randomly into 4 equal groups (T0, T1, T2 and T3) of 9 animals each according to body weight (bw). The rabbits were divided throughout the trial, the animals were fed, those of group T0 (control) with a standard feed without any type of leaf powder, while those of groups 1, 2 and 3 received the standard feed supplemented with Mangifera indica, Persea americana and Psidium guajava leaves powder at the rate of 0.5% respectively. After two months of treatment, the animals were fasted for 12 hours (20 h - 8 h) and sacrificed to evaluate carcass and digestive organ weights. The results revealed that the values of feed intake, live weight and weight gain were non-significantly (p > 0.05) increased in all animals regardless of the ration in reference to the control. The different leaves powder induced an increase in carcass yield in rabbits but this increase was only significant (p M. indica leaf powder (51.03 ± 0.24) as compared to the control (48.63 ± 0.74). Gut length was significantly increased in animals fed rations containing Psidium guajava and Persea americana leaves powder compared to the control. A significant increase in gut weight was observed in animals fed the Persea americana leaf supplemented ration. In general, mango leaf powder performed better than other types of powders.
文摘Detection of the presence of Anastrepha striata and Anastrepha ludens in guava cultures is presently done in Mexico by actually catching the flies in strategically located traps. The objective of this study is to show that it is possible to locate areas with the presence or absence of flies by remote sensing means, thereby simplifying the traditional way of detection of these plagues. In the field, groups of traps were selected where flies had been captured, as well as areas in which there was no capture in the traps. The radiometric signatures of whole trees and leaves were obtained, showing measurable differences between those specimens affected by the plague and those unaffected. Next we selected a SPOT5 image of 2007 corresponding to the study area in Calvillo, State of Aguascalientes, in Mexico, one of the major areas of guava cultures in the country. A supervised classification of the image allowed for the location of guava cultures in it. The guava culture areas obtained from this classification were validated comparing them to available maps of the cultured areas. Spectral signatures for the classes were derived from the image data. The separability of pairs of classes was also evaluated in order to maximize it. The IR/R （infrared to red ratio） ratio of the image bands was evaluated in 80 × 80 pixels around the locations of five traps where flies had been captured, and around five locations where the traps had not captured flies. Only the pixels where guava cultures were present were included in the analysis, other types of vegetation and soil coverage were rejected. We found that the index distributions with flies captured and those without flies captured cluster in two well-separated groups. We note that plotting the whole distribution of pixels around a trap yields a diagnostic view of the area, and individual index values do not provide such a view, since values with the flies＇ presence and without these overlap to some extent. Further analyses of other trap locations confirmed this separation and also revealed a third group of intermediate values between the two above, that are interpreted as locations in which the guava cultures are affected by the plague at an early stage of development, where the flies are not captured by the traps since they do not yet hatch. We concluded that it is possible to use remote sensing techniques to identify the presence ofAnastrepha striata and Anastrepha ludens in cultures of Psidium guajava L., even probably at early stages of development of the plague.
文摘The leaf-response to three-soil applied treatments of Paclobutrazol (PBZ;1000, 2000 and 0 ppm-control) was studied in a high-density plantation of eight guava (Psidium guajava) genotypes trees. All materials were prunned in vase form, with two to three major branches, yearly prunning for triggering the annual production cycle, and average height of 2.0 m. The dataset comprises fourth radiometric indices highly related to plant physiological activities. The dataset model took into account data collection dates, guava genotypes, and the positional effect of sun radiation on leaves based on their proximity to the canopy level and downward to the base of the woody seasonal-branch. Unexpectedly, there were no significant differences (NS) in PBZ treatments for genotypes, leaf position and radiometric indices. Analysis of the radiometric indices data revealed that anthocyanin (ARI index) and chlorophyll (PRI index) have a strong inverse relationship. Significant differences (P ≤ 0.05) were found between guava genotypes, and anthocyanin content;these results show that guava genotypes have varied responses, which could derive in their classification based-on drought resistance or low water requirements, however, it is important to note that additional research is required to determine the scope of these indications.
文摘Field studies were carried out during kharif 2016 and summer 2017 at Udyanagiri,UHS,Bagalkot,Karnataka,India to evaluate IPM modules against fruit fly in an already established guava orchard of variety Sardar(L-49).Among four modules,the mean fruit damage was significantly the lowest in M3(0.68%)followed by M2(1.19%)and M1(2.21%)and were on par with each other during kharif 2016.During summer 2017,M3 recorded significantly lowest damage(0.59%)followed by M2(0.92%)and M1(2.41%)but were on with each other.The highest per cent protection was afforded by M3(95.76 and 96.76,respectively)during 2016 and 2017.The average fruit yield over the years of experimentation revealed significantly the highest fruit yield(8.13 t/ha)from M3 followed by M2(7.32 t/ha)and M1(5.31 t/ha).Among the four modules,highest B:C was from M3(7.65)followed by M2(6.67)and M1(4.91).
文摘Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B （protein tyrosine phosphatase 1b） was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.
文摘Objective: To observe the clinical effect of guava leaf (GL) in treating infantile rotaviral enteritis.Methods: Sixty-two patients of rotaviral enteritis were randomly divided into the treated group treated with GL and the control group treated with Gegen Qinlian Decoction. The time for ceasing diarrhea, content of Na+ in blood, content of Na+ and glucose in stool, and the rate of negative conversion of human rotavirus antigen (HRVA) were observed.Results: The 3-day recovery rate in the treated group (87.1%) was significantly higher than that in the control group (58.1%, P<0.05). The time of ceasing diarrhea in the treated group (25.1±9.5 hrs) was significantly shorter than that in the control group (38.7±15.2 hrs, P<0.01). Moreover, content of Na+ and glucose in stool were reduced obviously in the treated group but not in the control group; and negative conversion rate of HRVA in the former group also got better than that in the latter group (87.1% vs 58.1%, P<0.05). Consequently, the effect of GL was superior to that of the control significantly.Conclusion: GL has good curative effect on infantile rotaviral enteritis.
