Anti-inflammatory and antioxidant activity of Thai mango (Mangifera indica Linn.) leaf extracts

Mango (Mangifera indica Linn.) has been widely studied as a folk medicines and it has become a common ingredient in cosmeceutical products. However, there was no report on the efficacy of Thai mango leaf extracts against inflammation. Thus, the aim of this study was to ascertain the anti-inflammatory and antioxidant activities of methanol (MeOH) and aqueous (Aq) extracts from the leaves of three mango varieties: Keaw Morakot, Nam Doc Mai, and Mahajanaka. To assay in vitro anti-inflammatory activity, the amount of nitric oxide (NO) released from macrophage cells was indirectly measured. Since free radicals play an important role in the inflammatory process, the antioxidant activity of M. indica leaf extracts was measured by ABTS and DPPH radical scavenging, ascorbic acid, and total phenolic assays. Mangiferin was also analyzed by HPLC. The most effective extract was selected and tested for anti-inflammatory activity in an animal model, an acute ear edema test in albino rats. The MeOH extract of Mahajanaka (M-MeOH) reduced nitric oxide production by LPS-stimulated macrophage cell lines RAW 264.7. M-MeOH showed the strongest antioxidant activity and it was, therefore, selected for an in vivo anti-inflammatory assay. An acute ear edema test in albino rats showed that M-MeOH exhibited significant anti-inflammatory activity compared to the control; ethyl phenylpropiolate-induced ear edema (P < 0.05). Moreover, mangiferin, a bioactive compound in M. indica leaves was detected in MeOH and Aq extracts. We concluded that the MeOH extract of M. indica leaves exhibits an anti-inflammatory property, both in vitro and in vivo, due to the presence of efficacious antioxidants.