In vitro anti-aging activities of extracts from leaves of Ma Kiang (Cleistocalyx nervosum var. paniala)

Context: Cleistocalyx nervosum (DC.) Kosterm. var. paniala (Roxb.) J. Parn. & Chantaran. (Myrtaceae) or Ma Kiang contains high amounts of phenolic compounds. Antioxidant activity of its fruit and seed has been investigated. However, limited available information concerning the biological activities of its leaves has been reported. Objective: To investigate the in vitro anti-aging potential of young and old leaves of Ma Kiang. Materials and methods: Ma Kiang leaves were extracted using water, methanol, and chloroform as the solvents by cold (sonication) and hot (boiling) processes. The extracts were determined for total phenolic and flavonoid contents. The extracts (at 0.001-10 mg/ml) were tested for antioxidative and tyrosinase inhibition activities using a colorimetric method. The cytotoxicity of extracts (at 0.0001-1 mg/ml) was determined with human skin fibroblasts. Also, the extracts at 0.001, 0.01, and 0.1 mg/ml which showed no toxicity were tested for MMP-2 inhibition. Results: The cold methanol extract of the old leaves showed the highest total phenolic and flavonoid contents of 511.44 +/- 18.23 mu g GAE/mg and 262.96 +/- 2.98 mg QE/mg, respectively. This extract also gave high free radical scavenging, lipid peroxidation inhibition, and tyrosinase inhibition activities with SC50, IPC50, and IC50 values of 0.02 +/- 0.004, 0.23 +/- 0.13, and 0.02 +/- 0.006 mg/ml, respectively. The extract at 0.1 mg/ml exhibited the highest MMP-2 inhibition of 91.14 +/- 1.67%. Discussion and conclusion: The anti-aging potential of the cold methanol extract from old leaves of Ma Kiang can be further developed as an anti-aging agent.