COMPARATIVE PHYTOCHEMICAL COMPOSITION, ANTIOXIDANT AND ALPHA AMYLASE INHIBITORY ACTIVITIES OF AQEUOUS EXTRACTS OF Mangifera indica (MANGO) LEAVES AND STEM BARK OBTAINED BY MACERATION AND DECOCTION TECHNIQUES

ABSTRACT

Phytochemicals are bioactive organic chemical compounds found 9n roots, leaves, bark or flowers of medicinal plants. These compounds play a defensive role against major chronic diseases. While various preparation techniques are utilized when using medicinal plants, the most important factors that might affect the quality of a plant extract are the plant component used, the solvent and its concentration, and the extraction technique. This study investigated the phytochemical composition, antioxidant, and antihyperglycemic activities of the cold and hot aqueous extracts of Magnifera indica (Mango) leaves and stem bark. Phytochemical screening of the cold and hot aqueous extracts of the stem bark and leaves revealed the presence of alkaloids, flavonoids, phenols, amino acids, and reducing sugars. HPLC analyses revealed the major presence of mangiferin, chlorogenic acid, quercetin, catechin and gallic acid in all extracts. In vitro DPPH radical scavenging assays revealed significant activities for the cold aqueous leaf extract (IC₅₀ = 88.1µg/mL) and the hot aqueous stem bark extract (IC₅₀ = 158.9 µg/mL) comparable with the standard. The hot aqueous extract of the leaves and the cold aqueous extract of the stem bark performed poorly. For the ferric reducing antioxidant power, the hot aqueous leaf extract had a significantly higher activity than the cold extract at all concentrations. For the stem bark, the cold and hot extracts displayed potent activities with the hot extract displaying a slightly higher activity than the cold extract. With respect to the alpha amylase inhibitory activity, the hot aqueous extract showed the best activity (IC₅₀ = 83.3 µg/mL) followed by the cold leaf extract (IC₅₀ = 139.6µg/mL), the cold stem bark (IC₅₀ = 139.6µg/mL151.5µg/mL), with the hot stem bark extract displaying the least activity (IC₅₀ = 189.9µg/mL). This study concluded that the choice of either hot or cold aqueous preparation would depend on the plant part utilized and the target activity.