PHYTOCHEMICALS AND ANTIOXIDANT ACTIVITIES OF NEEM (Azadirachta indica) LEAVES

Abstract

Fresh Neem leaves were collected from Dharan (Pindeswori Campus), Sunsari district, Nepal and were well washed with distilled water and subjected to cabinet drying at 50ºC until constant weight of sample was obtained. Thus, obtained dry powder was extracted using soxhlet apparatus in two different solvents i.e. methanol and ethanol and further concentrated using rotatory vacuum evaporator that was used for total phenol content (TPC), total flavonoid content (TFC) and tannin content determination. The mean values of methanolic and ethanolic extract were then statistically analyzed at 5% level of significance by paired t-test. Similarly, 99% methanol was used to determine total antioxidant capacity (TOAC), DPPH radical scavenging activity and reducing power assay of fresh Neem leaves. The preliminary phytochemical analysis of aqueous extract of Neem showed presence of protein, carbohydrates, phenols, tannin, steroids, terpenoids and glycosides. Total phenol content (mg GAE/g), total flavonoid content (mg QE/g) and tannin content (mg GAE/g) of methanolic and ethanolic extract of Neem were respectively 28.09± 0.31 and 22.88±0.24, 98.76±6.4 and 67.1 ±2.86, 1.55±0.79and 1.4±0.14 respectively. The methanol and ethanol extract showed significant difference in the phytochemical contents (p-value<0.05). Similarly, total antioxidant capacity (TOAC), DPPH radical scavenging assay and reducing power of fresh Neem leaves was found to be 91.49±0.24%, 71.91±0.04%, 51.08±0.85% of dry mass respectively. Overall, the study shows that Neem contains significant amount of phytochemicals and possess good antioxidant properties too.