Location: Natural Products Utilization ResearchTitle: Microbial metabolism Part 12 isolation characterization and bioactivity evaluation of eighteen microbial metabolites of 4'-hydroxyflavanone Author
Submitted to: Chemical and Pharmaceutical Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2011
Publication Date: 3/24/2011
Citation: Mikell, J.R., Herath, W., Khan, I.A. 2011. Microbial metabolism Part 12 isolation characterization and bioactivity evaluation of eighteen microbial metabolites of 4'-hydroxyflavanone. Chemical and Pharmaceutical Bulletin. 59(6):692-697. Interpretive Summary: Flavonoids are associated with many beneficial biological activities including antioxidant, antiproliferative and estrogenic properties. They are being consumed in measurable amounts by man. As such, it is important to determine their metabolic pathways to evaluate the potential risks and benefits to human health. One such compound with biological activities is 4’-hydroxyflavanone, a synthetic analogue of flavanones. The structures of mammalian metabolites obtained during many investigations were tentatively identified due to lack of material. In this study, extensive metabolism of 4'-hydroxyflavanone by the fungal cultures was observed with the formation of 18 compounds showing metabolic pathways similar to those observed in mammalian systems underlining the importance of using microbial models to mimic mammalian metabolism of xenobiotics. The completely characterized microbial metabolites of 4’-hydroxyflavanone could thus, be utilized to confirm tentatively identified mammalian metabolites due to lack of material and also to carry out further pharmacological studies. However, none of the metabolites obtained in this study showed activity when subjected to available tests, namely, antibacterial, antiviral and antihelmenthis.
Technical Abstract: 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-B-D-4-methoxyglucopyranoside (3), 4'-hydroxyflavanone 3'-sulfate (4), 6,4'-dihydroxyflavanone 3'-sulfate (5) and 4'-hydroxyflavanone 6-O-B-D-4-methoxyglucopyranoside (7). B. bassiana (ATCC 13144) and B. bassiana (ATCC 7159) in addition, gave one more metabolite each, namely, flavanone 4'-O-B-D-4-methoxyglucopyranoside (6) and 6,4'-dihydroxyflavanone (8) respectively. Cunninghamella echinulata (ATCC 9244) transformed 1 to 6,4'-dihydroxyflavanone (8), flavanone-4'-O-B-D-glucopyranoside (9), 3'-hydroxyflavanone 4'-sulfate (10), 3',4'-dihydroxyflavanone (11) and 4'-hydroxyflavanone-3'-O-B-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-a-D-6-deoxyallopyranoside (18) and 2,4-cis-4-hydroxyflavanone 4'-O-a-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.