Evaluation of Mulberroside A Production and Bioactivities from Endophytic Fungus and In Vitro Cultures of Morus alba

Abstract

Morus alba (mulberry) extracts were reported to have some bioactivities such as α-glucosidase and tyrosinase inhibitory activities. Root part of M. alba contains high level of mulberroside A, a glycoside form of oxyresveratrol. This major compound shows many pharmacological activities including anti-tyrosinase activity, anti-viral activity, antioxidant activity, hepatoprotective effect, and neuroprotective effect. In this study, mulberroside A accumulation, α-glucosidase and tyrosinase inhibitory activities of endophytic fungus, in vitro cultures from Morus alba extracts and intact M. alba were determined and compared to evaluate them as alternative sources of secondary metabolites. The results show that mulberroside A concentrations in cell suspension and root cultures of M. alba were higher than the intact fibrous root (10.31±0.76, 19.34±0.53 and 5.32±0.37 mg/g dry weight, respectively). Cell suspension and root cultures also showed higher anti α-glucosidase activity (IC₅₀ = 0.11±0.01 mg DW/mL, 86±0.9 ng DW/mL and 0.34±0.02 mg DW/mL, respectively) and anti-tyrosinase activity than that found in intact root (IC₅₀ = 0.70±0.05, 0.76±0.06 and 3.20±0.19 mg dry weight/mL, respectively). It is concluded that in vitro cultures of M. alba are potential sources of bioactive secondary metabolites. Additionally medium extract of endophytic fungus isolated from M. alba (identified as Trichoderma sp.) show positive mulberroside A accumulation (0.40±0.03 mg/g crude extract), an anti α-glucosidase activity (IC₅₀ = 0.81±0.12 mg crude extract/mL) and anti-tyrosinase activity (IC₅₀ = 3.72±0.58 mg crude extract/mL)