Correlation Between Antioxidant Property and Total Phenolic and Flavonoid Content of Azadirachta indica A Juss Flowers

Abstract

The present study investigated the antioxidant activity of shade dried neem flower powder extracts by DPPH, phospomolybdenum, and FRAP methods respectively. The antioxidant activity of different extracts of neem flower powder has been investigated. Among them, 80% hydroalcoholic extract displayed the highest scavenging activity with the IC50 value of 18 mg/L in phospomolybdenum assay, 29 mg/L in DPPH, 30 mg/L in FRAP assay. Whereas Pet. ether (PE) extract shows lowest antioxidant potential amongst them with the IC50 value of 76 mg/L in FRAP, 37 mg/L DPPH, 28 mg/L in phospomolybdenum assay. On examining the total phenolic and flavonoid content of extracts, 80% hydroalcoholic extract possesses the greatest phenolic content about 83.88 mg/L followed by methanol, acetone and PE about 62.05, 7.52, 3.56 mg/L respectively. The highest flavonoid content of 57.36 mg/L in 80% hydroalcoholic extract followed by methanol, acetone and PE about 20.56, 11.25, 1.56 mg/L respectively. The order of total phenolic and flavonoid content of extracts are found to be: 80% hydroalcoholic > methanol > acetone > pet. ether respectively. The correlation between the antioxidant and total phenolic and flavonoid content was calculated using Prism Pad software and observed at 95% confidence interval level. From the correlation graph, it is observed that there is a good correlation between antioxidant, total phenolic (phospomolybdenum assay, R2 – 0.702), and total flavonoid (DPPH assay, R2 – 0.665) content, and it is possible to suggest that total phenolic and flavonoid content of the plant extracts are the reason for the antioxidant activity.