Volatile components from Rhizoma Alpiniae Officinarum were respectively extracted by three methods including hydrodistillation, headspace solid-phase microextraction （HS-SPME） and diethyl ether extraction. A total o...Volatile components from Rhizoma Alpiniae Officinarum were respectively extracted by three methods including hydrodistillation, headspace solid-phase microextraction （HS-SPME） and diethyl ether extraction. A total of 40 （hydrodistillation）, 32 （HS-SPME） and 37 （diethyl ether extraction） compounds were respectively identified by gas chromatography-mass spectrometry （GC/MS） and 22 compounds were overlapped, including β-farnesene, 7-muurolene, 2,6-dimethyl-6- （4-methyl-3-pentenyl）bicyclo[3.1.1]hept-2-ene, eucalyptol and cadina-1（10）, 4-diene and so forth, varying in relative contents. HS-SPME is fast, sample saving and solvent-free and it also can achieve similar profiles as those from hydrodistillation and solvent extraction. Therefore, it can be the priority for extracting volatile components from medicinal plants.展开更多
Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of...Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of conventional repellents being sold in the market,though some of these repellent are not environmentally friendly and An.gambiae have developed resistance to some of these repellents.To this end,the phytochemical constituents and insecticidal activity of crude extracts of Hyptis suaveolens(bush mint)was determined on adult An.gambiae mosquitoes collected from Lafia,Nasarawa State,Nigeria to evaluate its effect in controlling them.Here,70%ethanolic and diethyl ether fat crude extracts were made from H.suaveolens dried leaves and used to carry out the experiment.The phytochemical screening of the ethanol extract revealed the presence of alkaloids,flavonoid,saponins,tannins,steroids and reducing sugar.Glycoside was not detected in the ethanol extract.Only steroids was detected in diethyl ether extract the rest of the phytochemical tested were absent.An.gambiae larvae were collected from the field and were raised to F1 progeny adults that were used for the study.WHO protocol for carrying out human bait repellency cage test was used.Human hand treated with the extracts was exposed to a cage containing 30 female mosquitoes for each of the extracts respectively.The ethanolic crude extract treatment proved to be more effective in repelling mosquitoes with 0%(0/30)mosquito landing than diethyl ether extract which had 40%(12/30)mosquitoes landing and the control hand(untreated left hand)had the highest landing rate 63.3%(19/30)which showed very high significant difference(χ^(2)=27.2619,df=2,P<0.00001)in relation to the treatments.After 24 hours holding period,the mortality rate of exposed mosquitoes was observed to be highest in the ethanolic treatment 73.3%(22/30).In conclusion,H.suaveolens extracts have repellency potential in controlling adult An.gambiae.展开更多
基金supported by the Industry-University-Research Cooperation Program from Science and Technology Department of Guangdong Province (No:2010B090400533)the International Scientific and Technological Cooperation Program of China (No:2009DFA31230)
文摘Volatile components from Rhizoma Alpiniae Officinarum were respectively extracted by three methods including hydrodistillation, headspace solid-phase microextraction （HS-SPME） and diethyl ether extraction. A total of 40 （hydrodistillation）, 32 （HS-SPME） and 37 （diethyl ether extraction） compounds were respectively identified by gas chromatography-mass spectrometry （GC/MS） and 22 compounds were overlapped, including β-farnesene, 7-muurolene, 2,6-dimethyl-6- （4-methyl-3-pentenyl）bicyclo[3.1.1]hept-2-ene, eucalyptol and cadina-1（10）, 4-diene and so forth, varying in relative contents. HS-SPME is fast, sample saving and solvent-free and it also can achieve similar profiles as those from hydrodistillation and solvent extraction. Therefore, it can be the priority for extracting volatile components from medicinal plants.
文摘Anopheles gambiae is a vector that is responsible for the transmission of malaria parasites which causes high morbidity and mortality in Nigeria and the world at large.Human-vector contact can be reduced by the use of conventional repellents being sold in the market,though some of these repellent are not environmentally friendly and An.gambiae have developed resistance to some of these repellents.To this end,the phytochemical constituents and insecticidal activity of crude extracts of Hyptis suaveolens(bush mint)was determined on adult An.gambiae mosquitoes collected from Lafia,Nasarawa State,Nigeria to evaluate its effect in controlling them.Here,70%ethanolic and diethyl ether fat crude extracts were made from H.suaveolens dried leaves and used to carry out the experiment.The phytochemical screening of the ethanol extract revealed the presence of alkaloids,flavonoid,saponins,tannins,steroids and reducing sugar.Glycoside was not detected in the ethanol extract.Only steroids was detected in diethyl ether extract the rest of the phytochemical tested were absent.An.gambiae larvae were collected from the field and were raised to F1 progeny adults that were used for the study.WHO protocol for carrying out human bait repellency cage test was used.Human hand treated with the extracts was exposed to a cage containing 30 female mosquitoes for each of the extracts respectively.The ethanolic crude extract treatment proved to be more effective in repelling mosquitoes with 0%(0/30)mosquito landing than diethyl ether extract which had 40%(12/30)mosquitoes landing and the control hand(untreated left hand)had the highest landing rate 63.3%(19/30)which showed very high significant difference(χ^(2)=27.2619,df=2,P<0.00001)in relation to the treatments.After 24 hours holding period,the mortality rate of exposed mosquitoes was observed to be highest in the ethanolic treatment 73.3%(22/30).In conclusion,H.suaveolens extracts have repellency potential in controlling adult An.gambiae.
