草果精油萃取方法及清除DPPH自由基能力研究

采用水蒸气蒸馏-乙醚萃取法和Clevenger法萃取草果挥发性成分,分别以1.12%和1.87%的平均得率获得了精油。采用GC/MS分析方法从水蒸气蒸馏-乙醚萃取获得的精油中检测出30种成分,解析鉴定出其中29个成分,总相对含量占精油全部组分的99.619%,主要成分为1,8-桉树脑(41.433%)、α-水芹烯(7.882%)、2-异丙基苯甲醛(5.930%)。Clevenger法所得精油检测出38种成分,解析鉴定出其中32个成分,总相对含量占精油全部组分的98.395%,主要成分为1,8-桉树脑(40.891%)、α-水芹烯(9.769%)、2-异丙基苯甲醛(6.988%)。两种方法获得的精油都具有明显的清除DPPH自由基能力,在浓度为10 mg/mL时,以水蒸气蒸馏-乙醚萃取法和Clevenger法所获得的精油对DPPH的清除率分别为80.0%和75.8%。

Chemical composition of essential oils and in vitro antioxidant activity of fresh and dry leaves crude extracts of medicinal plant of Lactuca Sativa L.native to sultanate of Oman

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.

Component Composition of Essential Oils <i>Curcuma longa</i>L. (Zingiberaceae) Introduced in Uzbekistan

This article presents the results of studying the component composition of essential oils of leaves and rhizomes of C. longa grown in Uzbekistan. The chemical composition of essential oils of vegetative organs of the Curcuma longa (Zingiberaceae) plant introduced in Uzbekistan was studied for the first time. Essential oils of the plant were isolated by hydrodistillation, their chemical composition was studied by chromatography-mass spectrometry. In the composition of essential oils of leaves and rhizomes C. longa L., introduced in the Tashkent oasis, found 27 and 16 components, respectively, among which the leaf is dominated by α-fellandren (33.79%), α-terpinolene (24.28%), n-cymene (12.27%), eucalyptol (9.77%), and in the rhizomes-6-(1,3-dimethyl-buta-1,3-dienyl)-1,5,5-trimethyl-7-oxa-bicyclo [4.1.0] hept-2-EN (22.77%), α-curcumene (4.11%), 2,6,6,9-tetramethyl-tricyclo [5.4.0.0(2.8)] undec-9-EN (3.81%), α-zedren (1.14%), as well as 3 components that were not identified (the mass spectrum did not match the library data) their mass fraction was 47.47%, 10.41% and 3.46%. The composition of leaves and rhizomes of C. longa differ quantitatively and in quality. For example, α-curcumene in percentage content is more contained in rhizomes, and α-fellandren, which is the dominant content in leaves, is not found in the underground part.

Composition analysis and antimicrobial activity of essential oil from leaves of Laurus nobilis grown in Oman

Traditionally,Laurus nobilis is used for the treatment of earaches and skin rashes as well as rheuma-tism.The most common technique to isolate the oil is hydro-distillation and steam-distillation.The investigation presented in this paper was aimed to unravel the antimicrobial activity and chemical composition of essential oil in the leaves of L.nobilis grown in Oman.The essential oil was extracted from the leave of the selected plant species by hydro distillation using Clevenger type apparatus.The antimicrobial assay was done by disc diffusion methods against three bac-terial strains,Staphylococcus aureus,Pseudomonas aeruginosa and Escherichia coli,and one fungal strain:Candida albicans.The isolated essential oil was analyzed by gas chromatography-mass spectrometry(GC-MS).The percentage yield of the essential oil was 0.064%(w/w).The essen-tial oil was found actively against the applied bacterial and fungal strains.The highest activity was found against S.aureus and the lowest was against E.coli,and the order was S.aureus>P.aeruginosa>E.coli.The essential oil was also active against the fungus C.albicans.The range of inhibition zones was 6-14 mm.The results of GC-MS analysis showed(E)-𝛽-caryophyllene to be the major component about 59.62%.Other major components included𝛼-selinene(14.03%),𝛼-humulene(8.65%),𝛽-selinene(4.99%),and𝛼-pinene(4.98%).In addition,several minor com-ponents were found in the essential oil of L.nobilis.Based on the experimental results,it showed that the plant species that grown in Oman were a potential source of therapeutic agents.In con-clusion,the essential oil and the plant could be used as natural and potential therapeutic agents to treat earaches,skin rashes,and rheumatism.