The isolation, purification and analysis of the melanin pigment extracted from Armillaria mellea rhizomorphs

The aim of present study was isolation and characteriation of raw and purified melanin from Armillaria mellea rhizomorphs. Native melanin was isolated from the rhizomorphs of A. mellea by alkaline extraction. Obtained pigment was purifed by acid hydrolysis and washed by organic solvents. Chemical tests, FT-IR and Raman spectroscopy analysis were conducted to determine the melanin nature of the isolated pigment. UV-Vis, transmittance and colour properties were evaluated. Antioxidant activity was determined using ABTS and antibacterial activity by a well diffusion method. The results of the study demonstrated that melanins isolated from A. mellea rhizomorphs had antioxidant, light barrier and antibacterial properties. A purified form of melanin offered better light properties and higher antioxidant activity than the raw form. Both melanins showed antimicrobial activity, raw melanin form had broader activity compared to the pure form. This study revealed that A. mellea rhizomorphs may be considered as a promising source of natural melanin. Isolated pigments presented all the physical and chemical properties common to natural and synthetic melanins. Raw and purified melanins showed differences in chemical composition, antioxidant activity and light barrier properties. Results of this study suggest that, melanins from A. mellea could be applied in the food, cosmetics and pharmaceutical industries.