Screening of medium composition for the free radical‐scavenging properties by Antrodia cinnamomea

The effects of nutritional conditions on the scavenging capacity on superoxide anion radical and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical of ethanolic extracts from filtrates of Antrodia cinnamomea were investigated in shake‐flask cultures. Culture medium significantly affected inhibition of superoxide anion generation and DPPH free radical scavenging activity. In contrast, both scavenging capabilities on superoxide anion radical and DPPH free radical were found to be greatly affected by varying the carbon source, the nitrogen source, the growth factors or the trace elements. The maximal inhibition of superoxide anion generation could be obtained when the culture medium compositions were: xylose, ammonium oxalate, nicotinic acid, NaH₂PO₄ and CuSO₄; while a maximal DPPH free radical scavenging activity could be achieved when the medium composition setting as: fructose, peptone, nicotinic acid, KH₂PO₄ and CaCl₂ (the scavenging effects on superoxide anion radical and DPPH free radical were increased to 96.3 ± 0.3% and 29.0 ± 1.0%, respectively). We proved that controlling the culturing conditions and modifying the composition of the medium can dramatically enhance the scavenging ability on superoxide anion radical and DPPH free radical of A. cinnamomea.