ABSTRACT
Tigernut, also known as Cyperus esculentus, is said to be high in nutritional and medicinal value. The purpose of this study was to determine the C. esculentus's antimutagenic activity. The ethanolic and aqueous extracts of the nut were analyzed for chemical constituents, antioxidants, ultraviolet-visible, and gas chromatography-mass spectrometry using standard procedures. The extracts contained a total of 17 major compounds that were docked against human RecQ-like protein 5 (RECQL5) helicase protein. The antimutagenic property of the ethanolic extract in vitro was assessed using the Allium cepa chromosome assay. Onion bulbs were pre-treated with 200 mg/kg of ethanolic extract of C. esculentus for 24 h and then, grown in NaN3 (250 µg/L) for 24 h; onion bulbs were also first exposed to NaN3 (250 µg/L) for 24 h before treatment with 100 mg/kg and 200 mg/kg of the ethanolic extract respectively. Standard methods were used to determine the mitotic index and chromosomal aberrations. Results revealed that C. esculentus ethanolic extract contained flavonoids (22.47 mg/g), tannins (0.08 mg/g), alkaloids (19.71 mg/g), glycosides, phenol, and tannin and showed high scavenging activity against 2,2-diphenyl-1-picrylhydrazyland H2O2. Docking with RECQL5 showed good binding energies (∆G>-7) of five compounds in C. esculentus ethanolic extract. The A. cepa assay results revealed a significant (P<0.05) reduction in chromosomal aberrations and a higher mitotic index in groups treated with the C. esculentus ethanolic extract. The antimutagenic activity of C. esculentus ethanolic extract was attributed to its high levels of phytosterols and phenolic compounds.
ABSTRACT
A dye-decolorizing bacterium was isolated from a soil sample and identified as Bacillus thuringiensis using 16S rRNA sequencing. The bacterium was able to decolorize three different textile dyes, namely, Reactive blue 13, Reactive red 58, and Reactive yellow 42, and a real dyehouse effluent up to 80-95% within 6 h. Some non-textile industrially important dyes were also decolorized to different extents. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometer analysis of the ethyl acetate extract of Congo red dye and its metabolites showed that the bacterium could degrade it by the asymmetric cleavage of the azo bonds to yield sodium (4- amino-3-diazenylnaphthalene-1-sulfonate) and phenylbenzene. Sodium (4-amino-3-diazenylnaphthalene-1-sulfonate) was further oxidized by the ortho-cleavage pathway to yield 2- (1-amino-2-diazenyl-2-formylvinyl) benzoic acid. There was induction of the activities of laccase and azoreductase during the decolorization of Congo red, which suggests their probable role in the biodegradation. B. thuringiensis was found to be versatile and could be used for industrial effluent biodegradation.
