Study On Chemical Composition And Antibacterial Action Of Two Kinds Of Lichen From Tibet

Study on Lichen is also at first stage, although there are many kinds of Lichen in Tibet. In order to take good advantage of Lichen, We have studied on Usnea longissima Ach. and Lethariella Cladonioides (NYI.) krog Syn. which were collected from Sejila Hills in Tibet. Hoping for not destroying the resource and exploiting natural anti-biotic substances, We have extracted, isolated anti-biotic substances and tested for antibacterial actioity of 3 compounds. The results are as follows:1 Study on chemical compounds and anti bacterical actioity of Usnea longissima Ach. and Lethariella Cladonioides (NYI.) krog Syn. with activity-guided isolation for the first time. Usnea longissima Ach. and Lethariella Cladonioides (NYI.) krog Syn. were extracted with benza, ethylacetate,ethanol and water, and studied on the inhibitive action of extracts with Staphylococcus arueus, Escherichia coli, Candida sp., Penicillium sp., and Fusarium oxysporum f.sp niveum Snyder et Hansen. The inhibitive action of extracts with ethanol form Usnea longissima Ach.is strongest. As well as extracts with ethylacetate from Lethariella Cladonioides (NYI.) krog Syn..2 A number of Usnea longissima Ach. were extracted with ethanol and got F1. F1 were re-crystallized many times, we got compoundâ… . The rest crude substance(16.571g)were subjected to silica gel column, SephadexLH-20 column, chromatography thin layer preparation and re-crystallization, the compoundâ…¡was got. A number of Lethariella Cladonioides (NYI.) krog Syn. were extracted with ethylacetate. The crude substance (2.25g) were dissolved with methanol .The compoundâ…¢were got from the part which are dissolvable in .3 MIC (minimum inhibition concentration) of compoundâ… ,â…¡andâ…¢against Staphylococcus arueus, Escherichia coli, Candida sp., Penicillium sp., and Fusarium oxysporum f.sp niveum Snyder et Hansen were determined qualitatively, Results showed that compoundâ… ,â…¡,â…¢have inhibition effect on tested bacteria to a certain extent, and worth of further study.