Melanins are enigmatic pigments that are produced by a wide variety of microorganisms including several species of bacteria and fungi. For more than 40 years, fungi have been known to produce pigments called melanins. Melanin pigment production by mushrooms was not intensively studied. The present study was carried out on isolation and characterization of melanin from an edible mushroom Pleurotus cystidiosus var. formosensis. The mushroom produced dark mucous mass of hyaline arthrospores on mycelium. The coremia exclusively produced dikaryotic arthrospores with the remnant of a clamp connection. Continuous cell extension and division in the coremium stipe supplied cells for arthroconidiation at the coremium apex, which is surrounded by a liquid droplet (coremioliquid). The black coloured coremea (conidia) were produced by Antromycopsis macrocarpa (anamorph of P. cystidiosus) when cultured on potato dextrose agar medium. The agar plate was incubated at continuous light illumination for high amount of pigment (coremea) production. The slimy layer of the coremea was extracted and partially purified by alkaline and acid treatment. The black pigment was confirmed as melanin based on UV, IR and EPR spectra apart from chemical analysis. This is the first report on characterization of melanin obtained from Pleurotus cystidiosus var. formosensis.

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The plants of Euphorbiaceae have high medicinal values and their phytochemical composition plays a major role in metal ion reduction. In this research, Euphorbia granulata (EG) the “spurge family” plant extract was used to reduce silver ions to silver nanoparticles (AgNPs). This nanoparticle formation was observed by UV-VIS spectrophotometric analysis at different times and temperatures to achieve the most optimal conditions. The synthesized biogenic silver nanoparticles (EG-AgNPs) were subjected to FTIR studies. The obtained low-intensity bands of fingerprint region bands (612 cm-1) and aromatic OH bands (3385 cm-1) are identified that the reduction of silver ions (Ag+) into metallic silver (Ag0) nanoparticles. Further, the charge, size, and morphology of the synthesized EG-AgNPs were studied using various spectroscopic methods including powder X-ray diffraction (XRD), high-resolution scanning electron microscope (HRSEM), FESEM-EDX elemental mapping, and high-resolution transmission electron microscope (HRTEM). The notable efficacy of the EG-AgNPs in antimicrobial activity including minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) suggested the EG-AgNPs are noteworthy material for biomedical applications. EG-AgNPs exhibited an efficient photocatalytic activity by degrading environmental pollutants, methylene blue (MB), and methyl orange (MO) dyes. The antioxidant property by radical scavenging (DPPH) assay of synthesized AgNPs was studied. Furthermore, the studied antioxidant behavior of EG-AgNPs by DPPH assay strongly supports that the EG-AgNPs are highly suitable materials for anticancer agents.

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