High‑Performance Liquid Chromatography Analysis and Antioxidant Activities of Extract of Azadirachta indica (Neem) Leaves

Background: Extracts from Azadirachta indica (A. indica) tend to provide numerous health benefits including antioxidant activity. The main objectives for this research were to use standard procedures to determine total phenols, total alkaloids, total flavonoid, 1,1‑diphenyl‑2‑picrylhydrazine (DPPH)‑scavenging activity, ferric reducing power, and total antioxidant capacity and analyze active components of the extracts using high‑performance liquid chromatography (HPLC). Materials and Methods: In vitro antioxidant potential of the A. indica extract was evaluated using DPPH and total antioxidant ability assays. Ferric reducing power ability of the extract was also examined using tannic acid and ascorbic acid as standard. Concentrations of plant extracts ranging from 0.02 to 0.10 mg/ml were prepared and mixed with appropriate volumes of reagents. Results: Methanol extract of A. indica exhibited higher content of phytochemical compounds (alkaloid = 1.9 mg QE/g; flavonoids = 3.5 mg QE/g; and phenols = 4.9 mg QE/g) at concentration 0.1 mg/ml compared to the acetone/water extract (alkaloid = 1.7 mg QE/g; flavonoids = 1.4 mg QE/g; and phenols = 2.6 mg QE/g). An overall trend found in the present study highlights the fact that the methanol extracts have better antioxidant capacities (DPPH, total antioxidant ability, and ferric reducing antioxidant property) than the acetone/water extract. HPLC analysis conducted also reveals seven peaks for methanol extract and six for acetone–water extract with different heights. Conclusion: HPLC analysis of A. indica extracts exhibited the presence of azadirachtin compound. The study showed that the extracts can competently protect the body against oxidative stress and therefore can be used as a source of potent natural antioxidant compounds.