Objective:To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L.(L...Objective:To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L.(L.sativa).Methods:The essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L.sativa(lettuce)grown in Sultanate of Oman by hydro distillation method.The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity(DPPH)method.Results:About 20 chemical compounds of different concentration representing 83.07%and 79.88%respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves asα-pinene(5.11%and 4.05%).γ-cymene(2.07%and 1.92%),thymol(11.55%and 10.73%),durenol(52.00%and 49.79%),α-terpinene(1.66%and 1.34%),thymol acetate(0.99%and 0.67%),caryophyllene(2.11%and 1.98%),spathulenol(3.09%and 2.98%).camphene(4.11%and3.65%),limonene(1.28%and 1.11%)representing these major chemical compounds.However,some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including p-pinene,α-terpinolene,linalool,4-terpineol,α-terpineol,o-methylthymol,L-alloaromadendrene and viridiflorene.Conclusions:The chemical consliluents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes,sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons.Therefore,the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant,antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases.展开更多
The effect of the processing parameters of Roselle seed on its oil yield was investigated.The seeds were ground and classified into two particle sizes(fine and coarse)using ASAE Standard S319.3.The samples were condit...The effect of the processing parameters of Roselle seed on its oil yield was investigated.The seeds were ground and classified into two particle sizes(fine and coarse)using ASAE Standard S319.3.The samples were conditioned by adding calculated amount of distilled water to different moisture levels from the initial moisture levels of 4.4%and 5.14%respectively,(fine,4.4%,6.4%,8.4%and 10.4%and coarse samples 5.14%,7.14%,9.14%and 11.14%w.b.).The samples were heated at different temperatures of 80,90,100 and 110℃over a period of 15,20,25 and 30 min,expressed at 15,22.5,30 and 37.5 MPa using hydraulic oil extractor for 10,20,30 and 40 min.Oil yield increases by 5%-6%with an increase in the processing parameters of pressure up to 30 MPa,temperature of 100℃and decreased beyond these points.Oil yield increased by 7%-8%with an increase in moisture content.Finely ground samples were found to have higher yield than coarsely ground samples at the different processing parameters.Processing parameters were found to affect the yield of oil from Roselle seeds.展开更多
基金Supported by Central Instrument Laboratory,College of Agriculture and Marine Sciences,Sultan Qaboos University,Grant No.507/SOP/OB/1/2013
文摘Objective:To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L.(L.sativa).Methods:The essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L.sativa(lettuce)grown in Sultanate of Oman by hydro distillation method.The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity(DPPH)method.Results:About 20 chemical compounds of different concentration representing 83.07%and 79.88%respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves asα-pinene(5.11%and 4.05%).γ-cymene(2.07%and 1.92%),thymol(11.55%and 10.73%),durenol(52.00%and 49.79%),α-terpinene(1.66%and 1.34%),thymol acetate(0.99%and 0.67%),caryophyllene(2.11%and 1.98%),spathulenol(3.09%and 2.98%).camphene(4.11%and3.65%),limonene(1.28%and 1.11%)representing these major chemical compounds.However,some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including p-pinene,α-terpinolene,linalool,4-terpineol,α-terpineol,o-methylthymol,L-alloaromadendrene and viridiflorene.Conclusions:The chemical consliluents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes,sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons.Therefore,the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant,antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases.
文摘The effect of the processing parameters of Roselle seed on its oil yield was investigated.The seeds were ground and classified into two particle sizes(fine and coarse)using ASAE Standard S319.3.The samples were conditioned by adding calculated amount of distilled water to different moisture levels from the initial moisture levels of 4.4%and 5.14%respectively,(fine,4.4%,6.4%,8.4%and 10.4%and coarse samples 5.14%,7.14%,9.14%and 11.14%w.b.).The samples were heated at different temperatures of 80,90,100 and 110℃over a period of 15,20,25 and 30 min,expressed at 15,22.5,30 and 37.5 MPa using hydraulic oil extractor for 10,20,30 and 40 min.Oil yield increases by 5%-6%with an increase in the processing parameters of pressure up to 30 MPa,temperature of 100℃and decreased beyond these points.Oil yield increased by 7%-8%with an increase in moisture content.Finely ground samples were found to have higher yield than coarsely ground samples at the different processing parameters.Processing parameters were found to affect the yield of oil from Roselle seeds.
