Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations b...Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations by formulating a double nano-emulsion(W/O/W)system incorporating macadamia oil and tea tree oil,using homogenization and phase inversion temperature(PIT)techniques.Comprehensive physicochemical charac-terization,including droplet size,polydispersity index(PDI),zeta potential,turbidity,Fourier transform infrared spectroscopy(FTIR),and SEM,was conducted alongside stability assessments under varying pH,temperature,and storage conditions.The optimized nano-emulsions exhibited nanoscale droplet sizes(10-40 nm),low PDI values(indicating high uniformity),and robust stability.Interestingly,the formulation with 2%W/O loading,with a particle size of 11.57 nm and a PDI of 0.04,demonstrated an antioxidant capacity of 4622.62μg ascorbic acid equivalents(AA)/g,which was significantly higher(p<0.05)compared to both natural oils(macadamia oil:20.91μg AA/g,tea tree oil:16.86μg AA/g)and a 10%Vitamin C aqueous solution(592.94μg AA/g).FTIR analysis confirmed the molecular integrity of Vitamin C and its successful encapsulation with macadamia and tea tree oils,while SEM images revealed uniformly spherical and well-dispersed droplets.Moreover,the formulation retained its structural integrity and antioxidant functionality under diverse pH and thermal conditions.These findings underscore the potential of double nano-emulsion systems to overcome the stability challenges of Vitamin C,offering a promising approach to enhance its bioavailability and therapeutic performance in phar-maceutical and cosmetic applications.展开更多
Background: Tea tree oil(TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes(PMNL) can actively respond to bovi...Background: Tea tree oil(TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes(PMNL) can actively respond to bovine mastitis infection. However, regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells(BMECs) and PMNL remain not reported. Therefore, aim of the study was to evaluate the effects of TTO extracts on the m RNA levels of the genes involved in the innate immune response of BMECs and PMNL.Results: Our results demonstrated that addition of 0.025% and 0.05% TTO increased the proliferation of BMECs, and significantly enhanced(P < 0.05) the viability of BMECs exposed to Staphylococcus aureus(S. aureus). An inhibitory effect was observed against the growth of S. aureus by TTO incubation. The 0.05% TTO reduced S. aureus biofilm formation, association and invasion of S. aureus to BMECs, and changed the morphological and structural features of S. aureus. The proinflammatory cytokines IL-1β, IL-6, and TNF-α were decreased(P < 0.001) by the incubation of TTO. Interestingly, the expression of IL-8 known for PMNL chemotactic function was elevated(P < 0.05) by 0.05%TTO treatment. Consistently, 0.05% TTO increased the migration of PMNL in S. aureus-exposed BMECs when compared with S. aureus treatment alone(P < 0.05). In addition, PMNL incubated with 0.05% TTO decreased the levels of NFKB inhibitor alpha(NFKBIA) and TNF-α.Conclusions: Our results indicate that use of TTO can relieve the BMECs pro-inflammatory response caused by S.aureus and promote the migration of PMNL to mount the innate immune responses, and it may be novel strategy for the treatment of bovine mastitis caused by S. aureus.展开更多
RAPD assessment on genetic variations of 45 tea trees in Yunnan was carried out. Eight primers selected from 40 random primers were used to amplify 45 tea samples, and a total of 95 DNA bands were amplified, of which ...RAPD assessment on genetic variations of 45 tea trees in Yunnan was carried out. Eight primers selected from 40 random primers were used to amplify 45 tea samples, and a total of 95 DNA bands were amplified, of which 90(94.7%)were polymorphism. The average number of DNA bands amplified by each primer was 11.5. Based on the results of UPGMA cluster analysis of 95 DNA bands amplified by 8 primers, all the tested materials could be classified into 7 groups including 5 complex groups and 2 simple groups, which was basically identical with morphological classification. In addition, there were some speciations in 2 simple groups.展开更多
Background:The prevalence of MRSA(Methicillin-resistant Staphylococcus aureus)colonized wounds in home care residents is expected to grow continuously as a result of the substantial proportion of older people requirin...Background:The prevalence of MRSA(Methicillin-resistant Staphylococcus aureus)colonized wounds in home care residents is expected to grow continuously as a result of the substantial proportion of older people requiring institutionalized care due to chronic disease and declining functional status,which contribute to more frequent skin breakdown and wound formation.Tea tree oil has been claimed to have anti-bacterial,analgesic and anti-inflammatory effects that have been suggested in many in-vitro studies to have good efficacy against MRSA.The aims of this study were to evaluate the effectiveness of 10%topical tea tree preparation to eradicateMRSA and to ascertain its influence on wound healing forMRSA-colonized wounds.Methods:It was a randomized controlled trial,single-blind study.Those with stage II or above MRSA-colonized wounds and who had given their informed consent formed the sample.The determined sample sizewasbasedonthe effect size of our previouspilot study,whichwas 0.46.Five outcome measurements were taken for the MRSA bacterial count and wound healing condition at baseline and at 1-week intervals during the 4-week dressing intervention period.Results:Thirty-two participants were recruited from two non-government nursing homes,16 in the control group and 16 in the tea tree oil group.The control group residents received routine saline gauze dressing,while the tea tree oil group residents received the 10%topical tea tree preparation dressing.In the tea tree oil group,all chronic wounds that had previously been delayed in healing were healed within 28 days without adverse reaction.MRSA was also completely eradicated in 14(87.5%)out of 16 wounds in the group receiving the 10%topical tea tree preparation.展开更多
Over the past few decades,complementary and alternative treatments have become increasingly popular worldwide.The purported therapeutic characteristics of natural products have come under increased scrutiny both in vi...Over the past few decades,complementary and alternative treatments have become increasingly popular worldwide.The purported therapeutic characteristics of natural products have come under increased scrutiny both in vitro and in vivo as part of efforts to legitimize their usage.One such product is tea tree oil(TTO),a volatile essential oil primarily obtained from the native Australian plant,Melaleuca alternifolia,which has diverse traditional and industrial applications such as topical preparations for the treatment of skin infections.Its anti-inflammatory-linked immunomodulatory actions have also been reported.This systematic review focuses on the anti-inflammatory effects of TTO and its main components that have shown strong immunomodulatory potential.An extensive literature search was performed electronically for data curation on worldwide accepted scientific databases,such as Web of Science,Google Scholar,PubMed,ScienceDirect,Scopus,and esteemed publishers such as Elsevier,Springer,Frontiers,and Taylor&Francis.Considering that the majority of pharmacological studies were conducted on crude oils only,the extracted data were critically analyzed to gain further insight into the prospects of TTO being used as a neuroprotective agent by drug formulation or dietary supplement.In addition,the active constituents contributing to the activity of TTO have not been well justified,and the core mechanisms need to be unveiled especially for anti-inflammatory and immunomodulatory effects leading to neuroprotection.Therefore,this review attempts to correlate the anti-inflammatory and immunomodulatory activity of TTO with its neuroprotective mechanisms.展开更多
[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average e...[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average extreme minimum temperature, annual average temperature, accumulative temperature ≥10 ℃ and annual rainfall as climatic zoning factors, regression model between zoning factors and geographic information was established, and comprehensive climatic zoning indicator of tea tree cultivation in Hanzhong was determined. [ Result] Tea tree cultivation in Hanzhong was divided into suitable, more suitable and unsuitable planting zones by using critical value of climatic zoning. [ Conclusion] The research could provide scientific basis for reasonable planning layout and sustainable development of tea tree in the whole city.展开更多
Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9...Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.展开更多
This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method.The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulati...This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method.The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly.Super-high encapsulation efficiency was achieved when a 40%volume fraction of ethanol was used for the microencapsulation procedure,where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3%and 94.3%,respec-tively.Additionally,considering the operation cost,including time and energy consumption,an economical preparation was validated so that it would be viable for large-scale production.Based on the results of morphological and X-ray diffraction analysis,the crystal structure appeared to differ before and after microencapsulation.The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules.Furthermore,the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object,and the hydrophilic property was proved by a water contact angle measurement.展开更多
To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigat...To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigate the relations between the age of oil-tea camellia trees and their growth rate of secondary trunk. The Gompertz equation Y=71.296 1exp （-3.874 4exp （-0.006 4t）） was the most optimal equation to simulate the accumulative growth rate of basal trunk disc. This equation could be used to estimate the age of oil-tea camellia trees that grow under similar environmental conditions. The Korf equation Y=576.900 1exp （-4.153 0x -0.314 2 ） was the best equation to describe the relation between the age and growth rate of different secondary trunks. With the adjustment coefficient and average growth of different secondary trunk discs, it is possible to predict the age of ancient oil-tea camellia trees that grow under similar environmental conditions. In addition, taking three or more discs from the same diameter group and calculating their average growth rate could lead to more accurate results. For trees that grow in different areas, environmental conditions should be carefully considered when using the above two equations to predict the age of ancient oil-tea camellia trees.展开更多
【目的】探究互叶白千层(澳洲茶树)精油(tea tree oil,TTO)超临界CO_(2)提取的最优条件及其精油的组成成分和抗氧化能力。【方法】采用响应面法优化超临界CO_(2)萃取参数,通过GC-MS结合保留指数(RI)法鉴定茶树精油的组成成分。采用DPPH...【目的】探究互叶白千层(澳洲茶树)精油(tea tree oil,TTO)超临界CO_(2)提取的最优条件及其精油的组成成分和抗氧化能力。【方法】采用响应面法优化超临界CO_(2)萃取参数,通过GC-MS结合保留指数(RI)法鉴定茶树精油的组成成分。采用DPPH及OH自由基清除试验分析茶树精油的体外抗氧化活性,以D-半乳糖致衰小鼠为模型,测定其血清及肝中SOD、GSH-Px、CAT活性及MDA含量来分析茶树精油的体内抗氧化活性。【结果】在30 MPa的萃取压力、55℃的萃取温度、150 min的萃取时间下,可以获得2.239%的茶树精油提取率,与响应面优化试验回归模型预测值(2.241%)接近。GC-MS结合RI分析表明,提取的茶树精油共分离出49种组分,其中含量高于1%的组分有16种,含量最高的组分为松油烯-4-醇。体内外抗氧化结果表明,茶树精油有着良好的抗氧化效果,能够有效减少DPPH和OH自由基的产生,使SOD、GSH-Px和CAT的浓度有所下降,同样能够有效减少MDA的含量。【结论】超临界CO_(2)萃取方法可以从互叶白千层中高效提取具有抗氧化活性的茶树精油。展开更多
基金Ho Chi Minh City University of Technology(HCMUT),VNU-HCM for supporting this study.
文摘Vitamin C,a potent antioxidant with broad therapeutic applications,is limited by rapid degradation under environmental stressors,which compromises its stability and bioactivity.This study addresses these limitations by formulating a double nano-emulsion(W/O/W)system incorporating macadamia oil and tea tree oil,using homogenization and phase inversion temperature(PIT)techniques.Comprehensive physicochemical charac-terization,including droplet size,polydispersity index(PDI),zeta potential,turbidity,Fourier transform infrared spectroscopy(FTIR),and SEM,was conducted alongside stability assessments under varying pH,temperature,and storage conditions.The optimized nano-emulsions exhibited nanoscale droplet sizes(10-40 nm),low PDI values(indicating high uniformity),and robust stability.Interestingly,the formulation with 2%W/O loading,with a particle size of 11.57 nm and a PDI of 0.04,demonstrated an antioxidant capacity of 4622.62μg ascorbic acid equivalents(AA)/g,which was significantly higher(p<0.05)compared to both natural oils(macadamia oil:20.91μg AA/g,tea tree oil:16.86μg AA/g)and a 10%Vitamin C aqueous solution(592.94μg AA/g).FTIR analysis confirmed the molecular integrity of Vitamin C and its successful encapsulation with macadamia and tea tree oils,while SEM images revealed uniformly spherical and well-dispersed droplets.Moreover,the formulation retained its structural integrity and antioxidant functionality under diverse pH and thermal conditions.These findings underscore the potential of double nano-emulsion systems to overcome the stability challenges of Vitamin C,offering a promising approach to enhance its bioavailability and therapeutic performance in phar-maceutical and cosmetic applications.
基金supported by the Research Project of Natural Science Foundation of Jiangsu Province (SBK2019043455)the National Natural Science Foundation of China (No. 31972589)+1 种基金China Agriculture Research System (CARS-36)Development Project of China (2017YFD0502104–3)。
文摘Background: Tea tree oil(TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes(PMNL) can actively respond to bovine mastitis infection. However, regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells(BMECs) and PMNL remain not reported. Therefore, aim of the study was to evaluate the effects of TTO extracts on the m RNA levels of the genes involved in the innate immune response of BMECs and PMNL.Results: Our results demonstrated that addition of 0.025% and 0.05% TTO increased the proliferation of BMECs, and significantly enhanced(P < 0.05) the viability of BMECs exposed to Staphylococcus aureus(S. aureus). An inhibitory effect was observed against the growth of S. aureus by TTO incubation. The 0.05% TTO reduced S. aureus biofilm formation, association and invasion of S. aureus to BMECs, and changed the morphological and structural features of S. aureus. The proinflammatory cytokines IL-1β, IL-6, and TNF-α were decreased(P < 0.001) by the incubation of TTO. Interestingly, the expression of IL-8 known for PMNL chemotactic function was elevated(P < 0.05) by 0.05%TTO treatment. Consistently, 0.05% TTO increased the migration of PMNL in S. aureus-exposed BMECs when compared with S. aureus treatment alone(P < 0.05). In addition, PMNL incubated with 0.05% TTO decreased the levels of NFKB inhibitor alpha(NFKBIA) and TNF-α.Conclusions: Our results indicate that use of TTO can relieve the BMECs pro-inflammatory response caused by S.aureus and promote the migration of PMNL to mount the innate immune responses, and it may be novel strategy for the treatment of bovine mastitis caused by S. aureus.
文摘RAPD assessment on genetic variations of 45 tea trees in Yunnan was carried out. Eight primers selected from 40 random primers were used to amplify 45 tea samples, and a total of 95 DNA bands were amplified, of which 90(94.7%)were polymorphism. The average number of DNA bands amplified by each primer was 11.5. Based on the results of UPGMA cluster analysis of 95 DNA bands amplified by 8 primers, all the tested materials could be classified into 7 groups including 5 complex groups and 2 simple groups, which was basically identical with morphological classification. In addition, there were some speciations in 2 simple groups.
文摘Background:The prevalence of MRSA(Methicillin-resistant Staphylococcus aureus)colonized wounds in home care residents is expected to grow continuously as a result of the substantial proportion of older people requiring institutionalized care due to chronic disease and declining functional status,which contribute to more frequent skin breakdown and wound formation.Tea tree oil has been claimed to have anti-bacterial,analgesic and anti-inflammatory effects that have been suggested in many in-vitro studies to have good efficacy against MRSA.The aims of this study were to evaluate the effectiveness of 10%topical tea tree preparation to eradicateMRSA and to ascertain its influence on wound healing forMRSA-colonized wounds.Methods:It was a randomized controlled trial,single-blind study.Those with stage II or above MRSA-colonized wounds and who had given their informed consent formed the sample.The determined sample sizewasbasedonthe effect size of our previouspilot study,whichwas 0.46.Five outcome measurements were taken for the MRSA bacterial count and wound healing condition at baseline and at 1-week intervals during the 4-week dressing intervention period.Results:Thirty-two participants were recruited from two non-government nursing homes,16 in the control group and 16 in the tea tree oil group.The control group residents received routine saline gauze dressing,while the tea tree oil group residents received the 10%topical tea tree preparation dressing.In the tea tree oil group,all chronic wounds that had previously been delayed in healing were healed within 28 days without adverse reaction.MRSA was also completely eradicated in 14(87.5%)out of 16 wounds in the group receiving the 10%topical tea tree preparation.
文摘Over the past few decades,complementary and alternative treatments have become increasingly popular worldwide.The purported therapeutic characteristics of natural products have come under increased scrutiny both in vitro and in vivo as part of efforts to legitimize their usage.One such product is tea tree oil(TTO),a volatile essential oil primarily obtained from the native Australian plant,Melaleuca alternifolia,which has diverse traditional and industrial applications such as topical preparations for the treatment of skin infections.Its anti-inflammatory-linked immunomodulatory actions have also been reported.This systematic review focuses on the anti-inflammatory effects of TTO and its main components that have shown strong immunomodulatory potential.An extensive literature search was performed electronically for data curation on worldwide accepted scientific databases,such as Web of Science,Google Scholar,PubMed,ScienceDirect,Scopus,and esteemed publishers such as Elsevier,Springer,Frontiers,and Taylor&Francis.Considering that the majority of pharmacological studies were conducted on crude oils only,the extracted data were critically analyzed to gain further insight into the prospects of TTO being used as a neuroprotective agent by drug formulation or dietary supplement.In addition,the active constituents contributing to the activity of TTO have not been well justified,and the core mechanisms need to be unveiled especially for anti-inflammatory and immunomodulatory effects leading to neuroprotection.Therefore,this review attempts to correlate the anti-inflammatory and immunomodulatory activity of TTO with its neuroprotective mechanisms.
文摘[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average extreme minimum temperature, annual average temperature, accumulative temperature ≥10 ℃ and annual rainfall as climatic zoning factors, regression model between zoning factors and geographic information was established, and comprehensive climatic zoning indicator of tea tree cultivation in Hanzhong was determined. [ Result] Tea tree cultivation in Hanzhong was divided into suitable, more suitable and unsuitable planting zones by using critical value of climatic zoning. [ Conclusion] The research could provide scientific basis for reasonable planning layout and sustainable development of tea tree in the whole city.
基金This work was supported by the project of Yunnan Innovation Team Project, the Hundreds Oversea Talents Program of Yunnan Province, the Top Talents Program of Yunnan Province （Grant 20080A009）, the Key Project of the Natural Science Foundation of Yunnan Province （201401 PC00397）, National Science Foundation of China （U0936603）, Key Project of Natural Science Foundation of Yunnan Province （2008CC016）, Frontier Grant of Kunming Institute of Botany, CAS （672705232515）, Top Talents Program of Yunnan Province （20080A009）, and Hundreds Talents Program of Chinese Academy of Sciences （CAS） （to L.G.）.
文摘Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.
基金the JST SPRING (Grant No.:JPMJSP2124)for the support of his life and this study.
文摘This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method.The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly.Super-high encapsulation efficiency was achieved when a 40%volume fraction of ethanol was used for the microencapsulation procedure,where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3%and 94.3%,respec-tively.Additionally,considering the operation cost,including time and energy consumption,an economical preparation was validated so that it would be viable for large-scale production.Based on the results of morphological and X-ray diffraction analysis,the crystal structure appeared to differ before and after microencapsulation.The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules.Furthermore,the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object,and the hydrophilic property was proved by a water contact angle measurement.
基金Supported by Hunan Forestry Science and Technology Project(XLK201707)
文摘To determine the age of oil-tea camellia trees, regression equations including Logistic, Mitscherlich, Gompertz, Korf, and Richards were used to calculate accumulative growth rate using basal trunk disc and investigate the relations between the age of oil-tea camellia trees and their growth rate of secondary trunk. The Gompertz equation Y=71.296 1exp （-3.874 4exp （-0.006 4t）） was the most optimal equation to simulate the accumulative growth rate of basal trunk disc. This equation could be used to estimate the age of oil-tea camellia trees that grow under similar environmental conditions. The Korf equation Y=576.900 1exp （-4.153 0x -0.314 2 ） was the best equation to describe the relation between the age and growth rate of different secondary trunks. With the adjustment coefficient and average growth of different secondary trunk discs, it is possible to predict the age of ancient oil-tea camellia trees that grow under similar environmental conditions. In addition, taking three or more discs from the same diameter group and calculating their average growth rate could lead to more accurate results. For trees that grow in different areas, environmental conditions should be carefully considered when using the above two equations to predict the age of ancient oil-tea camellia trees.
文摘【目的】探究互叶白千层(澳洲茶树)精油(tea tree oil,TTO)超临界CO_(2)提取的最优条件及其精油的组成成分和抗氧化能力。【方法】采用响应面法优化超临界CO_(2)萃取参数,通过GC-MS结合保留指数(RI)法鉴定茶树精油的组成成分。采用DPPH及OH自由基清除试验分析茶树精油的体外抗氧化活性,以D-半乳糖致衰小鼠为模型,测定其血清及肝中SOD、GSH-Px、CAT活性及MDA含量来分析茶树精油的体内抗氧化活性。【结果】在30 MPa的萃取压力、55℃的萃取温度、150 min的萃取时间下,可以获得2.239%的茶树精油提取率,与响应面优化试验回归模型预测值(2.241%)接近。GC-MS结合RI分析表明,提取的茶树精油共分离出49种组分,其中含量高于1%的组分有16种,含量最高的组分为松油烯-4-醇。体内外抗氧化结果表明,茶树精油有着良好的抗氧化效果,能够有效减少DPPH和OH自由基的产生,使SOD、GSH-Px和CAT的浓度有所下降,同样能够有效减少MDA的含量。【结论】超临界CO_(2)萃取方法可以从互叶白千层中高效提取具有抗氧化活性的茶树精油。
