Free radical scavenging activities of crude methanolic extract of Psidium Guajava leaves and its different fractions

Abstract

Psidium guajava leaves and its fruits are widely used as a source of food and for ethnomedicinal purposes in Boshundhara Baridhara of Bangladesh, but not many studies have been conducted on the locally grown species of the plant in the area. This study investigated the phytochemical, and antioxidant activities of crude methanolic extract of locally grown Psidium guajava leaves and its different fractions. A qualitative phytochemical analysis was carried out on the crude extract using standard scientific procedures. Furthermore, antioxidant activities of both the crude methanolic extract and the various fractions were assessed using DPPH (1, 1-diphenyl-2-picrylhydrazyl radical) test, with ascorbic acid as standard. The results showed the presence of saponins, alkaloids, flavonoid, and carbohydrate, and tannin was absent. The DPPH results showed that methanolic crude extract had the highest free radical scavenging activity with an IC50 value of 12.25 μg/ml, followed by the aqueous soluble fraction with an IC50 value of 14.45 μg/ml. Similarly, n-hexane fraction of the extract had a better activity (IC50 = 50.25 μg/ml) compared to those of carbon tetrachloride, dichloromethane soluble fraction whose IC50 values were recorded as 92.50.0 and 97.75 μg/ml respectively. These observations showed that polar fractions of the locally grown Psidium guajava leave could be good sources of antioxidants of natural origin.