Wild Mushrooms: Potential Natural Sources of Antioxidant and Anti-Quorum Sensing Bioactive Compounds for Medical Applications

Abstract

Objective. This study was aimed at determining the antioxidant, anti-quorum sensing, and in vitro cytotoxic activities of five wild mushroom extracts. Methods. Wild mushrooms of Auricularia auricula-judae, Termitomyces umkowaani, Trametes elegans, Trametes versicolor, and Microporus xanthopus were collected from Arabuko-Sokoke and Kakamega National Forests, in Kenya. Specimens were identified and extracted using chloroform (CHL), 70% ethanol (Eth), and hot water (HW) solvents. Antioxidant and cytotoxic activities of the extracts were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Vero cell lines, respectively, while anti-quorum sensing activities were tested against Chromobacterium violaceum. All data were compared using relevant descriptive and inferential statistics at a significance level of $p$  ≤ 0.05. Results. A total of 35 wild mushrooms were collected, identified, and classified into 14 genera. Among screened mycochemicals, fatty acids, flavonoids, polyphenols, and saponins were detected at higher concentrations. The highest free radical scavenging activities of A. auricula-judae, T. umkowaani, T. elegans, and T. versicolor were observed in 70% Eth extract with the percentage values of 76.40 ± 0.12%, 68.40 ± 0.01%, 62.40 ± 0.07%, and 66.40 ± 0.04%, respectively, whereas the HW extract of Microporus xanthopus showed free radical scavenging activity at 65.90 ± 0.02%. None of the extracts, at the tested concentrations (up to 1000 µg/mL), had shown cytotoxic activity against the Vero cell line. The HW extract of T. umkowaani and the 70% Eth extract of T. versicolor showed a statistically significant difference in the inhibitory activity of violacein production against C. violaceum at the concentration of 200 µg/mL. Conclusions. The antioxidant activity of wild mushrooms can help to tackle the diseases caused by free radicals. The anti-quorum sensing potential of wild mushrooms could also provide future alternatives to conventional drug therapies cost-effectively. Further detailed chemistry of the bioactive compounds and their possible mechanisms of action responsible for the observed antioxidant and anti-quorum sensing activities are needed.