Fluconazole treatment enhances extracellular release of red pigments in the fungus Monascus purpureus.

Traditional methods for the production of food grade pigments from the fungus Monascus spp. mostly rely on submerged fermentation. However, the cell-bound nature and intracellular accumulation of pigments in Monascus spp. is a major hurdle in pigment production by submerged fermentation. The present study focused on the investigation of the effect of the antifungal agent fluconazole on red pigment production from Monascus purpureus (NMCC-PF01). At the optimized concentration of fluconazole (30 µg ml-1), pigment production was found to be enhanced by 88% after 96 h and it remained constant even after further incubation up to 168 h. Ergosterol, a sterol specific to fungi, was also extracted and estimated as a function of fungal growth. The concentration of ergosterol in fluconazole-treated fermentation broth was reduced by 49% as compared to control broth. Thus it could be responsible for facilitating the release of intracellular and cell-bound pigments. Nevertheless, the role of cell transporters in transporting out the red pigments cannot be ignored and deserves further attention. Qualitative analysis of red pigment by thin layer chromatography, UV spectroscopy and mass spectrometric analysis (ESIMS) has confirmed the presence of the well-known pigment rubropunctamine. In addition, this fermentation process produces citrinin-free pigments. This novel approach will be useful to facilitate increased pigment production by the release of intracellular or cell-bound Monascus pigments.

Innovative approach for urease inhibition by Ficus carica extract-fabricated silver nanoparticles: An in vitro study.

In the present study, a rapid, low-cost, and ecofriendly method of stable silver nanoparticles (AgNPs) synthesis using leaves extract of Ficus carica (F. carica), a plant with diverse metabolic consortium, is reported for the first time. An absorption peak at 422 nm in UV-Vis spectroscopy, a spherical shape with an average size of 21 nm in transmission electron microscopy, and crystalline nature in X-ray powder diffraction studies were observed for the synthesized AgNPs. Fourier transform infrared analysis indicated that proteins of F. carica might have a vital role in AgNP synthesis and stabilization. AgNPs were found to inhibit urease, a key enzyme responsible for the survival and pathogenesis of the bacterium, Helicobacter pylori. Inhibition of urease by AgNPs was monitored spectrophotometrically by the evaluation of ammonia release. The urease inhibition potential of AgNPs can be explored in the treatment of H. pylori by preparing novel combinations of standard drugs with AgNPs- or AgNPs-encapsulated drug molecules.

Biofunctionalized silver nanoparticles as a novel colorimetric probe for melamine detection in raw milk.

Nanoparticles have emerged as a promising analytical tool for monitoring food adulteration and safety. In the present study, silver nanoparticles (AgNPs) were synthesized using leaves' extract of Jatropha gossypifolia. AgNPs revealed a characteristic surface plasmon resonance (SPR) peak at 419 nm and have spherical and grain shape with size range between 18 and 30 nm. A selective and rapid method of melamine detection in raw milk was developed with the use of these biofunctionalized AgNPs. The color change, deviation in SPR spectra, and change in the absorption ratio (A500 /A419 ) of AgNPs occurred after an AgNPs-melamine interaction. The detection limit for melamine up to 2 µM (252 ppb) was attained with this method, which is quite lower than safety level recommendations of regulatory bodies demonstrating sensitivity of the method. Dynamicx light scattering and transmission electron microscopy analyses exhibited an increase in hydrodynamic diameter and size of AgNPs after melamine interaction. Melamine sensing by AgNPs was investigated by different physicochemical and thermal analyses.