Isolation and Identification of Chlorinated Genistein from Actinoplanes sp. HBDN08 with Antioxidant and Antitumor Activities

Abstract

A strain Actinoplanes sp. HBDN08 was screened by PCR-guided method using primers derived from conserved regions of halogenase genes. A new chlorinated isoflavone, 3',8-dichlorogenistein (1), along with 8-chlorogenistein (2) were isolated from the fermentation broth of Actinoplanes sp. HBDN08. Their structures were elucidated on the basis of extensive 1D and 2D NMR as well as HRESI-MS, ESI-MS, UV, and IR spectroscopic analyses. The origin of the two compounds was also investigated by high-performance liquid chromatography (HPLC) analysis. The results demonstrated that they were not biosynthesized but derived from the biotransformation of genistein by Actinoplanes sp. HBDN08. The antioxidant activities of the isolated compounds 1 and 2 were evaluated by using the lipid peroxidation assay. Their antitumor activities were calculated according to the inhibitory rate of cell proliferation against the human breast cancer cell line MDA-MB-231. The results indicated that compounds 1 (IC(50) = 5.2 microM) and 2 (IC(50) = 7.5 microM) showed stronger antioxidant activities than genistein (IC(50) = 13.6 microM). In comparison with the antitumor activities of genistein, those of compounds 1 and 2 increased 7.7- and 2.6-fold, respectively. These results suggest that the PCR-guided screening strategy is a rapid method for obtaining halometabolite-producing strains. Moreover, these results reveal that chlorination has significant effects on the bioactivities of genistein. This could be important information for studying the structure-activity relationships of genistein.

In-situ Thermoelectrochemistry

“…Commercially available thermistor probes in the form of small bulbs were protected by an insulating layer, and the working electrode wire was wound around the thermistor [331,332]. Instead of thermistors, pyroelectric foils carrying electrode layers have been used for calorimetry in situ [343][344][345][346][347]. Heat exchange of reactions of adhering solid crystals were determined by such arrangements.…”

“…Also, graphite hollow cylinders in close contact to a thermistor have been used [333,334]. Layers of nickel [343] and of platinum [344,345] have been studied, and the heat exchange even of a submonolayer conversion [346] has been determined. Thermistor probes covered by thick electrode layers of copper [335,336], silver [337] or platinum [338] proved also to be useful (Fig.…”

Biotransformation of puerarin into puerarin-6″-O-phosphate by Bacillus cereus

“…HBDN08. The antioxidant activities of 3 0 ,8-dichlorogenistein and 8-chlorogenistein were about twice that of genistein [18]. Sulfation reactions of flavonoids have been notably observed.…”

Microbial production of natural and non-natural flavonoids: Pathway engineering, directed evolution and systems/synthetic biology

“…Besides these four major post-modification reactions, flavonoids are found to be modified by other diverse reactions in whole cell biotransformation while using microbial cells mainly fungi or actinomycetes. Those postmodification reactions are dehydroxylation (Lin et al, 2014), deglycosylation (Dajanta et al, 2009;You et al, 2010;Liu et al, 2013, Lin et al, 2014), hydrogenation (Correa et al, 2011Stompor et al, 2013), halogenation (Xiang et al, 2010), and sulfation (Ibrahim et al, 2010;Araujo et al, 2013). These post-modifications of flavonoids are still understudied and require extensive exploitation.…”