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Microbial metabolism of 7-hydroxyflavanone (1) with fungal culture Cunninghamella blakesleeana (ATCC 8688a), yielded flavanone 7-sulfate (2), 7,4'-dihydroxyflavanone (3), 6,7-dihydroxyflavanone (4), 6-hydroxyflavanone 7-sulfate (5), and 7-hydroxyflavanone 6-sulfate (6). Mortierella zonata (ATCC 13309) also transformed 1 to metabolites 2 and 3 as well as 4'-hydroxyflavanone 7-sulfate (7), flavan-4-cis-ol 7-sulfate (8), 2',4'-dihydroxychalcone (9), 7,8-dihydroxyflavanone (10), 8-hydroxyflavanone 7-sulfate (11), and 8-methoxy-7-hydroxyflavanone (12). Beauveria bassiana (ATCC 7159) metabolized 1 to 2, 3, and 8, flavanone 7-O-β-D-O-4-methoxyglucopyranoside (13), and 8-hydroxyflavanone 7-O-β-D-O-4-methoxyglucopyranoside (14). Chaetomium cochlioides (ATCC 10195) also transformed 1 to 2, 3, 9, together with 7-hydroxy-4-cis-ol (15). Mucor ramannianus (ATCC 9628) metabolized 1 in addition to 7, to also 4,2',4'-trihydroxychalcone (16), 7,3',4'-trihydroxyflavanone (17), 4'-hydroxyflavanone 7-O-α-L-rhamnopyranoside (18), and 7,3',4'-trihydroxy-6-methoxyflavanone (19). The organism Aspergillus alliaceus (ATCC 10060) transformed 1 to metabolites 3, 16, 7,8,4'-trihydroxyflavanone (20), and 7-hydroxyflavanone 4'-sulfate (21). A metabolite of 1, flavanone 7-O-β-D-O-glucopyranoside (22) was produced by Rhizopus oryzae (ATCC 11145). Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antimalarial activities against selected organisms. Metabolites 4 and 16 showed weak antileishmanial activity.

Fermentation of 4'-hydroxyflavanone (1) with fungal cultures, Beauveria bassiana (ATCC 13144 and ATCC 7159) yielded 6,3',4'-trihydroxyflavanone (2), 3',4'-dihydroxyflavanone 6-O-β-D-4-methoxyglucopyranoside (3), 4'-hydroxyflavanone 3'-sulfate (4), 6,4'-dihydroxyflavanone 3'-sulfate (5) and 4'-hydroxyflavanone 6-O-β-D-4-methoxyglucopyranoside (7). B. bassiana (ATCC 13144) and B. bassiana (ATCC 7159) in addition, gave one more metabolite each, namely, flavanone 4'-O-β-D-4-methoxyglucopyranoside (6) and 6,4'-dihydroxyflavanone (8) respectively. Cunninghamella echinulata (ATCC 9244) transformed 1 to 6,4'-dihydroxyflavanone (8), flavanone-4'-O-β-D-glucopyranoside (9), 3'-hydroxyflavanone 4'-sulfate (10), 3',4'-dihydroxyflavanone (11) and 4'-hydroxyflavanone-3'-O-β-D-glucopyranoside (12). Mucor ramannianus (ATCC 9628) metabolized 1 to 2,4-trans-4'-hydroxyflavan-4-ol (13), 2,4-cis-4'-hydroxyflavan-4-ol (14), 2,4-trans-3',4'-dihydroxyflavan-4-ol (15), 2,4-cis-3',4'-dihydroxyflavan-4-ol (16), 2,4-trans-3'-hydroxy-4'-methoxyflavan-4-ol (17), flavanone 4'-O-α-D-6-deoxyallopyranoside (18) and 2,4-cis-4-hydroxyflavanone 4'-O-α-D-6-deoxyallopyranoside (19). Metabolites 13 and 14 were also produced by Ramichloridium anceps (ATCC 15672). The former was also produced by C. echinulata. Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antiprotozoal activities against selected organisms.

Incubation of a communic acid-derived synthon with Cunninghamella elegans quantitatively affords 1 beta, 3 beta- and 7 beta- monohydroxylated derivatives.

Geothermal soils near Amphitheater Springs in Yellowstone National Park were characterized by high temperatures (up to 70 degrees C), high heavy metal content, low pH values (down to pH 2.7), sparse vegetation, and limited organic carbon. From these soils we cultured 16 fungal species. Two of these species were thermophilic, and six were thermotolerant. We cultured only three of these species from nearby cool (0 to 22 degrees C) soils. Transect studies revealed that higher numbers of CFUs occurred in and below the root zone of the perennial plant Dichanthelium lanuginosum (hot springs panic grass). The dynamics of fungal CFUs in geothermal soil and nearby nongeothermal soil were investigated for 12 months by examining soil cores and in situ mesocosms. For all of the fungal species studied, the temperature of the soil from which the organisms were cultured corresponded with their optimum axenic growth temperature.