Nutrient composition, antioxidant properties, and anti-proliferative activity of Lignosus rhinocerus Cooke sclerotium

Abstract

Background: Lignosus rhinocerus (tiger milk mushroom) is an important medicinal mushroom used in Southeast Asia and China, and its sclerotium can be developed into functional food/nutraceuticals. The nutrient composition, antioxidant properties, and anti-proliferative activity of wild type and a cultivated strain of L. rhinocerus sclerotia were investigated.

Results: The sclerotial powder has high carbohydrate but low fat content. Interestingly, the cultivated strain contains higher amounts of protein and water-soluble substances than the wild type. Phenolic content of hot-water, cold-water, and methanol extracts of the sclerotial powders ranged from 19.32 to 29.42 mg gallic acid equivalents g⁻¹ extract, while the ferric reducing antioxidant power values ranged from 0.006 to 0.016 mmol min⁻¹ g⁻¹ extract. The DPPH• , ABTS•⁺ , and superoxide anion radical scavenging activities of the extracts ranged from 0.52 to 1.12, 0.05 to 0.20, and -0.98 to 11.23 mmol Trolox equivalents g⁻¹ extract, respectively. Both strains exhibited strong superoxide anion radical scavenging activity comparable to rutin. The cold-water extracts exhibited anti-proliferative activity against human breast carcinoma (MCF-7) cells, with IC₅₀ values of 206 µg mL⁻¹ and 90 µg mL⁻¹ for the wild type and cultivated strains, respectively.

Conclusion: The cultivated L. rhinocerus sclerotium has the potential to be developed into functional food/nutraceuticals.

Keywords: Lignosus rhinocerus; anti-proliferative activity; antioxidant activity; nutritional composition; phenolic content; tiger milk mushroom.