The cultivation of many crops in Africa is negatively affected by a number of constraints, the most important of which is the incidence of pests and diseases. In many areas of the world, the most preferred option in t...The cultivation of many crops in Africa is negatively affected by a number of constraints, the most important of which is the incidence of pests and diseases. In many areas of the world, the most preferred option in the management of pests is the application of synthetic chemical pesticides. Due to the negative effects of pesticides on humans and the environment as a whole, efforts are being made to find alternatives for pest management. Ethanolic extracts of the leaves and roots of Lantana camara were tested against the major pests of okra, Abelmoschus esculentus. The plant extracts were compared with a standard chemical insecticide, Mektin (a.i 18 g/L abamectin) in a randomly complete block design with four treatments and three replications. Parameters studied included the major pests of the plant and the damage caused, leaf area, plant height as well as yield of okra. Cotton aphids, Aphis gossypii, the tobacco whitefly Bemisia tabaci and the cotton flea beetle, Podagrica puncticollis were the major pests encountered on okra plants. Aphis gossypii and B. tabaci populations were significantly lower on the L. camara-sprayed plots compared with the control plots. Similarly, P. puncticollis numbers were significantly smaller on the L. camara-sprayed plots than the control plots. There were no significant differences between the treatments and the control for plant height, leaf area and yield. The significant reduction in pests numbers on the L. camara-sprayed plots indicates its potential as an alternative to chemical insecticides, thereby reducing the reliance on chemical insecticides in the management of insect pests.展开更多
Two compounds with different bioactivities were isolated from the leaves of the Lantana camara Linn plant.Compound 1 was triterpenoid(Lantadene B)(22β-dimethylacroyloxy-3-oxoolean-12-en-28-oic-acid,C_(35)H_(52)O_5),w...Two compounds with different bioactivities were isolated from the leaves of the Lantana camara Linn plant.Compound 1 was triterpenoid(Lantadene B)(22β-dimethylacroyloxy-3-oxoolean-12-en-28-oic-acid,C_(35)H_(52)O_5),which was isolated from n-hexane fraction and obtained as white solid(amorphous).Compound 2 was glycoside flavonoid(5-hydroxy-6,4′-dimethoxy flavon-7-O-glucopyranose,C_(23)H_(24)O_(11)),which was isolated from ethyl acetate and obtained as pale yellow solid(amorphous).Extraction was performed with maceration method using methanol solvent.Subsequently,fractionation was carried out using n-hexane and ethyl acetate solvents.Isolation and purification of both fractions were conducted using chromatography method.The structure of the isolated compounds was determined through spectral analyses of ultraviolet(UV),infrared(IR),and nuclear magnetic resonance(~1H NMR and ^(13)C NMR),distortionless enhancement by polarization transfer(DEPT),heteronuclear multiple bond connectivity(HMBC),heteronuclear single quantum correlation(HSQC),and H-H COSY(~1H-~1H homonuclear correlated spectroscopy).The cytotoxic activity of compound 1 was tested against MCF-7 breast cancer cells in vitro using MTT assay(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide),showing very strong cytotoxic activity in inhibiting the growth of MCF-7 breast cancer cells,and the IC_(50) value was 1.1336μM.The antioxidant activity of compound 2 was tested using DPPHassay(1,1-diphenyl-2-picrylhydrazyl),showing strong activity in inhibiting free radicals,and its IC_(50) value was 71.03 mg/L.展开更多
文摘The cultivation of many crops in Africa is negatively affected by a number of constraints, the most important of which is the incidence of pests and diseases. In many areas of the world, the most preferred option in the management of pests is the application of synthetic chemical pesticides. Due to the negative effects of pesticides on humans and the environment as a whole, efforts are being made to find alternatives for pest management. Ethanolic extracts of the leaves and roots of Lantana camara were tested against the major pests of okra, Abelmoschus esculentus. The plant extracts were compared with a standard chemical insecticide, Mektin (a.i 18 g/L abamectin) in a randomly complete block design with four treatments and three replications. Parameters studied included the major pests of the plant and the damage caused, leaf area, plant height as well as yield of okra. Cotton aphids, Aphis gossypii, the tobacco whitefly Bemisia tabaci and the cotton flea beetle, Podagrica puncticollis were the major pests encountered on okra plants. Aphis gossypii and B. tabaci populations were significantly lower on the L. camara-sprayed plots compared with the control plots. Similarly, P. puncticollis numbers were significantly smaller on the L. camara-sprayed plots than the control plots. There were no significant differences between the treatments and the control for plant height, leaf area and yield. The significant reduction in pests numbers on the L. camara-sprayed plots indicates its potential as an alternative to chemical insecticides, thereby reducing the reliance on chemical insecticides in the management of insect pests.
文摘Two compounds with different bioactivities were isolated from the leaves of the Lantana camara Linn plant.Compound 1 was triterpenoid(Lantadene B)(22β-dimethylacroyloxy-3-oxoolean-12-en-28-oic-acid,C_(35)H_(52)O_5),which was isolated from n-hexane fraction and obtained as white solid(amorphous).Compound 2 was glycoside flavonoid(5-hydroxy-6,4′-dimethoxy flavon-7-O-glucopyranose,C_(23)H_(24)O_(11)),which was isolated from ethyl acetate and obtained as pale yellow solid(amorphous).Extraction was performed with maceration method using methanol solvent.Subsequently,fractionation was carried out using n-hexane and ethyl acetate solvents.Isolation and purification of both fractions were conducted using chromatography method.The structure of the isolated compounds was determined through spectral analyses of ultraviolet(UV),infrared(IR),and nuclear magnetic resonance(~1H NMR and ^(13)C NMR),distortionless enhancement by polarization transfer(DEPT),heteronuclear multiple bond connectivity(HMBC),heteronuclear single quantum correlation(HSQC),and H-H COSY(~1H-~1H homonuclear correlated spectroscopy).The cytotoxic activity of compound 1 was tested against MCF-7 breast cancer cells in vitro using MTT assay(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide),showing very strong cytotoxic activity in inhibiting the growth of MCF-7 breast cancer cells,and the IC_(50) value was 1.1336μM.The antioxidant activity of compound 2 was tested using DPPHassay(1,1-diphenyl-2-picrylhydrazyl),showing strong activity in inhibiting free radicals,and its IC_(50) value was 71.03 mg/L.
