Phytochemical, Metabolite Profile and Antioxidant Activity of Azadirachta indica Leaf Extracts from Two Different Locations

Abstract

Azadirachta indica commonly known as Neem is widely distributed for more than a thousand years as one of the most versatile medicinal plant having wide spectrum of biological activities. The aim of this work is comparative study on phytochemicals, metabolites profiling and antioxidant activity of Azadirachta indica leaf extracts from two different locations. Samples were collected from Gaya and Nassarawa L. G. As in Kano State, identified, extracted with ethanol and subjected to phytochemical screening using standard methods. Metabolite profiling and antioxidant activity of the crude ethanol extracts were evaluated by TLC analysis and DPPH radical scavenging assay respectively. Phytochemical screening of the crude extracts revealed the presence of flavonoid, phenolic, fat and oil but coumarin, carboxylic acid and emodine were found to be absent. Tannin was found to be present in the sample obtained from Gaya while absent Nassarawa sample. TLC analysis of the extracts revealed the presence of similar compounds but with some variations. The extract of the sample obtained from Gaya was found to be the most active in DPPH radical scavenging assay by revealing the IC₅₀ value of 13.70µgml^-1 relative to other test samples. The plant extract obtained from Nassarawa demonstrated higher antioxidant activity than BHT (IC₅₀ 39.95µgml^-1) but lower than ascorbic acid (IC₅₀ 20.34µgml^-1) and Gaya sample. The variation in the antioxidant activity of the two samples can be attributed to the presence of tannin in one sample but absent in the other sample which could be due to geographical variation.