Flavones and New Isoflavone Derivatives from Microorganisms: Isolation and Structure Elucidation

Abstract

In the course of our chemical screening of actinomycetes and other bacteria from terrestrial and marine sources, several extracts showed colourless middle polar bands with strong UV absorption at 254 nm and brown to grey colouration with anisaldehyde/sulphuric acid. Working-up of such strains led to the isolation of a number of isoflavonoids. Daidzein (1a) and genistein (1b) are very wide-spread, however, compounds like kakkatin (2b, Streptomyces sp. GW39/1530) were known only from plant sources. Additionally, three new isoflavonoids were obtained, namely 4',7-bis-(β -cymaropyranosyl)-genistein (1e) and 4'-hydroxy-6,7-methoxyisoflavone (2c) from the actinomycete isolate HKI 129-L, and genistein-4'-(6"-methyl)-salicylate (1d) from Streptomyces sp. isolate GW27/2506. 1d is the first natural 4'-ester of an isoflavonoid and an aromatic acid. For the first time, also two flavonoids were isolated from bacteria, apigenin (5a) and luteolin-3'-methyl ether (5b).

A comprehensive review of glycosylated bacterial natural products

“…528 In addition, the Streptomyces -derived actinoflavoside carries the rare 3′-amino-2′,3′,6′-trideoxy-ribopyranoside (α-D-ristosamine, 69 ) at C-7. 527 Intriguingly, while genistein rhamnosides lack antifungal activity, the corresponding talosides (talosins A and B) 532 were reported as potent antifungals, implicating the inversion of a single stereo-center (C-3′) within the appended sugar as the distinguishing feature that invokes antifungal activity.…”

A new isoflavone derivative from Streptomyces sp. YIM GS3536

“…Streptomycetes are capable of biotransformation of soybean meal as major organic medium components and production of various isoflavones [5][6][7][8][9][10][11][12][13][14][15]. In our search for new metabolites from actinomycetes, a new compound, 7-O-methyl-8-chlorogenistein (1), together with eight known isoflavones, 8-chlorogenistein (2) [10], kakkatin (3) [7], 7-O-methyl genistein (4) [7], genistein (5) [14], daidzein (6) [7], glycitin (7) [16], genistin (8) [17], and daidzin (9) [18], was isolated from the Streptomyces strain YIM GS3536, which was isolated from soil sample collected from Yunnan Province, P. R. China.…”

“…Compounds 2-9 were known isoflavone derivatives. Their structures were identified as 8-chlorogenistein (2) [10], kakkatin (3) [7], 7-O-methyl genistein (4) [7], genistein (5) [14], daidzein (6) [7], glycitin (7) [16], genistin (8) [17], and daidzin (9) [18] by comparison of their spectroscopic data with those in the related literature. …”

Antimicrobial and Antioxidant Isoflavonoid Derivatives from the Roots of Amphimas pterocarpoides

“…Comparison of the 1 H NMR spectra of 3 and the methylated derivative 3m revealed a supplemental methoxy group in 3m by a singlet appearing at δ H = 3.81 ppm. Amongst these derivatives, 3a and 3p are reported here for the first time whereas 3m was already described [7,9,12]. The results of the antibacterial assays indicated that neither the extract nor the isolated compounds have good activities.…”

“…Although compounds 2 and 3 were previously obtained from metabolism of daidzein and from microorganisms, respectively [9,10], it is the first time that these compounds are reported from a plant, to the best of our knowledge.…”