Abstract:
The antioxidant lotion containing 1% mangiferin, which was previously isolated from leaves of mango variety Nam Doc Mai (purity 93.15%, HPTLC analysis), was prepared. The lotion was an o/w type of emulsion with slightly yellow and coconut scent. The viscosity and pH of the lotion were 19,809 centipoise and 5.94, respectively. Stability studies were performed at room temperature (25±5 °C) with 70±10%RH and at high temperature (45±2 °C) with 75%RH. The amount of mangiferin in the lotion was investigated at various time intervals by HPTLC. The results showed that mangiferin in the lotion remained 80.30±1.87%LA after storage for 3 months at room temperature. While it remained less than 80%LA after storage for 2 weeks at high temperature and only 38.51±0.35%LA remained after 3 months of storage. An unknown degradant was detected at the Rf value of 0.24. It was produced increasingly when storage peroid taken longer, especially at the high temperature. UV spectra of the degradant and mangiferin suggested the similarity of their chemical structures. Antioxidant activity of the lotion was evaluated by DPPH radical scavenging method. Interestingly, the activity has not decreased at both temperatures during storage times even if mangiferin degraded. It was possible that the degradant could scavenge DPPH redical and chemical structure of the degradant might be xanthone.
