Honeybee chitosan-melanin complex: isolation and investigation of antimicrobial activity

Abstract

Antimicrobial activity of marine crustaceans chitosans is well studied and is widely used in medicine, while chitosans of insects are poorly investigated in this aspect, though they might also be of practical significance. The aim of this study was to isolate and purify chitosan-melanin complex (CMC) from the honeybee­ corpses and to estimate its antimicrobial activity. Antibacterial activity of CMC was evaluated by MTT test, antifungal activity towards Candida albicans was estimated by calculating colony forming units (CFU method). The modified method of CMC isolation and purification was described which differs from the known analogs in deacetylation of chitin-melanin complex by its hydrolysis in 40% NaOH without previous melanin elimination and in further purification of CMC by differential solubilization at distinct pH values. The anti-microbial activity of CMC was characterized by prevalence of candidacidal effect, IC50 towards laboratory strain of C. albicans was 50 μg/ml. The ranking of studied bacteria sensitivity to the CMC action decreased as: E. coli > St. aureus > Ps. aeruginosa. It is suggested that CMC isolated from the honeybee corpses might be a perspective constituent of medicinal compositions for treatment of lesions caused by C. albicans infection.

Keywords

• chitosan-melanin complex
• honeybee corpses
• mtt test
• antimicrobial activity