Enhanced antioxidant and antitumor activities of Antrodia cinnamomea cultured with cereal substrates in solid state fermentation

Growing exclusively on stout camphor trees in Taiwan, Antrodia cinnamomea is known for its extraordinary antioxidant and antitumor activities. As an alternative to the limited supply of natural source, cultured A. cinnamomea from solid state or submerged liquid fermentation still offers many of its medicinal effects. To further enhance the production of functional compounds and corresponding activities, oat, wheat, buckwheat and pearl barley were used as substrates for solid state fermentation of A. cinnamomea in this study. Among these cereal-based culturing, the methanol extract of A. cinnamomea mycelia grown on oats showed stronger overall antioxidant properties. EC₅₀ for the antioxidant activity (conjugated diene method), the DPPH radicals scavenging ability and reducing power were estimated to be around 0.57 mg/mL, 1.07 mg/mL and 0.31 mg/mL, respectively. Incubating cultured cells with 150 ppm of the oat-cultured mycelial extract for 24 h greatly reduced the viability of MCF-7 breast cancer cells and HepG2 hepatocellular carcinoma cells to 29% and 76%, while 3T3 normal fibroblasts were virtually unaffected. In general, cereal-based solid state fermentation of A. cinnamomea produced more of the secondary metabolites and their methanolic extracts showed stronger antioxidant and anti-tumor activities than extracts obtained from liquid fermentation at the same concentration.