Gas chromatography-mass spectrometry analysis of different organic crude extracts from the local medicinal plant of Thymus vulgaris L

Objective:To isolate and analyze the chemical composition in different crude extracts of from the leaves of locally grown of Thymus vulgaris L(T.vulgaris)by gas chromatography-mass spectrometry(GC-MS).Methods:The shade dried leaves powder was extracted with methanol by using Soxhlet extractor.Methanol crude extracts of T.vulgaris and the derived fractions of hexane,chloroform,ethyl acetate and butanol were obtained.Results:Qualitative analyses of various organic crude extracts of T.vulgaris by using GC-MS showed that there were different types of high and low molecular weight compounds.Most of the isolated and identified compounds by GC-MS in the crude extracts are basically biologically important.Further,the T.vulgaris leaf possessed certain characteristics that can be ascribed to cultivation on a domestic plantation.The crude extracts were prepared from the powder leaves of T.vulgaris for respective compounds can be chosen on the basis of above GC-MS analysis.Conclusions:All the major compounds were identified and characterized by spectroscopic method in different organic crude extracts of T.vulgaris are biologically active molecules.Thus the identification of a good number of compounds in various crude extracts of T.vulgaris might have some ecological role.

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.

Studies on free-radical scavenging activity and identification of active ingredients of different plant crude extracts of Mentha piperita collected from Sur,Sultanate of Oman

Objective:To determine free radical scavenging activity and active chemical ingredients of different plant crude extracts of Mentha piperita(M.piperita).Methods:The dried powder leaves of M.piperita were extracted with polar organic solvent by Soxhlet extractor.The crude extract and its fractions of hexane,chloroform,ethyl acetate and butanol crude extracts were prepared.The antioxidant activity of different crude extracts from M.piperita was carried out by DPPH method with minor modification,and the active chemical ingredients of different plant crude extracts of M.piperita were analyzed by gas chromatography-mass spectrometry(GC-MS).Results:Qualitative analysis of different polarities crude extracts by GC-MS found different types of active organic compounds.The antioxidant activity of different crude extracts were found to be in the order of chloroform extract>butanol extract>ethyl acetate extract>hexane extract>methanol extract.Majority identified compounds in the plant crude extracts by GC-MS were biologically active.Conclusions:Therefore,the isolation,purification,identification and characterization of bioactive compounds from various crude extracts of M.piperita might have ecological significance.

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.