Study On Secondary Metabolites Of Soil Fungi And Their Activities In

Microbial fungus is one of the important source for natural products research. This article briefly introduced the secondary metabolite of the Paraconiothyrium and the Microsphaeropsis in the first part of this thesis. In this dissertation, two fungi strains were selected from the rhizospheric microbial resources associated with Panax notoginseng by chemical diversity screening using TLC methods. YIM PH30473 and YIMPH30472 were identified as Paraconiothyrium sporulosum and Microsphaeropsis arundinis, respectively. The secondary metabolites of the two fungi were separated and their chemical structures were identified. In addition, the biological activities of chemical entities have also been tested.12 compounds included a-cyclopiazonic acid (1), pseurotinA (2), ditryptophenaline (3), ergosta-7,24(28)-dien-3-ol (4), orsellinic acid (5), orcinol (6), uracil (7), flufuran (8), octadeca-9,12,15-trienoic acid (9), stearic acid (10), methyl palmitate (11), a-maltose (12) were isolated from the culture broth of YIM PH30473. Compounds a-cyclopiazonic acid (1), pseurotin A (2) exhibited certain antifungal activity against Escherichia coli with MICs at 64μg/mL. In addition, some of these compounds indicate medium synergistic antifungal activity. The DPPH antioxidant activities of some compounds were also studied, but the effect is not ideal.4 compounds included one new compound, arundinisin A (1), (4S)-4,8-dihydroxy-3,4-dihydro-1(2H)-naphthalen-1-one (2), (S)-4,6,8-trihydroxy-3,4-dihydro-1(2H)-naphthalenone-l-one (3), chrysogeside D (4) were isolated from the fermentation broth of YIM PH30472. Arundinisin A (1) and chrysogeside D (4) exhibited modest antifungal activity against Alternaria tenuissima with MICs at 64μg/mL. Chrysogeside D (4) exhibited medium antifungal activity against Alternaria tenuissima with MIC of 64μg/mL.The results proved that the microbial resources associated with Panax notoginseng were abundantly, and these fungi can produce the secondary metabolites with complex structures and strong activity. As a result, the effective utilization of these fungi can enrich the database of microbial natural products.