Investigation On The Secondary Metabolites Of Two Endophytes From Chinese Medicines

The genus Cochliobolus is comprised of more than forty closely related families. Tribulus terrestris have been used as a tradition Chinese Medicine.8purified strains have been isolated from the plant of T. terrestris. Through analysis of TLC of the strains crude extracts, a candidate (C. sp) was chosed as the top strain.27compounds were isolated from the fermentation extract by means of column chromatography, preparative thin layer chromatography (TLC), high pressure liquid chromatography (HPLC), and recrystallization. Their structures were elucidated by extensive spectroscopic analysis, including7carbohydrates (Cs-1-Cs-7),6alkaloid glycosides (Cs-8-Cs-13),8steroids (Cs-14-Cs-21),3benzene derivatives (Cs-22-Cs-24), and3lactones (Cs-25-Cs-27).Cordyceps. Sinensis (Berk.), Clavicipitaceae family, is distributed in alpine regions of Qinhai, Sichuan, Yunnan, Gansu and some other places.3purified strains have been isolated from this medicine. Through analysis of TLC, HPLC, and activity screening of the crude extracts, Alternaria tenuissima was chosed.7compounds were obtained from the fermentation extract. The structures of these compounds were elucidated, including2alkaloids (At-1and At-2),4benzene derivatives (At-3-At-6), and1steroid (At-7).This dissertation focused on the fermentation condition, isolation, and structure elucidation of secondary metabolites of the endophytes. The chemical profiles of two endophytes were systematically investigated. The results of this thesis were expected to enrich the database of nature products and were favor for the exploration and utilization of endophytes.