Phytochemical and Antioxidant Profiling of n-Hexane and Ethyl Acetate Fractions of Psidium guajava Flowers

Abstract

The phytochemical composition and antioxidant activity of the n-hexane and ethyl acetate fractions of the methanol crude extract of Psidium guajava flowers were investigated. The plant material was collected from Emeyal I community, Bayelsa State, Nigeria, air-dried, pulverized, and macerated in methanol for 72 hours, followed by successive partitioning using n-hexane and ethyl acetate. The percentage yields of the fractions were 0.497% and 0.869% for the n-hexane and ethyl acetate fractions, respectively, indicating a higher abundance of moderately polar constituents. Qualitative phytochemical screening revealed the presence of steroids and glycosides in the n-hexane fraction, while alkaloids, flavonoids, and glycosides were detected in the ethyl acetate fraction. Thin-layer chromatography profiling showed multiple components with optimal resolution achieved using n-hexane: ethyl acetate (3:1) for the n-hexane fraction (six spots) and (1:3) for the ethyl acetate fraction (four spots), confirming the complexity of the phytochemical constituents.

The antioxidant activity, evaluated using the DPPH radical scavenging assay at concentrations ranging from 50–400 µg/mL, showed a concentration-dependent increase in inhibition for both fractions. The ethyl acetate fraction exhibited higher radical scavenging activity, comparable to the standard ascorbic acid, indicating strong antioxidant potential.

These findings demonstrate that Psidium guajava flowers are a rich source of bioactive phytochemicals, particularly moderately polar compounds such as flavonoids, which significantly contribute to antioxidant activity. The study highlights the pharmacological potential of this underexplored plant part and underscores the importance of solvent fractionation in enhancing bioactive compound recovery. Further studies are recommended to isolate, characterize, and evaluate the specific compounds responsible for the observed bioactivity for potential pharmaceutical and nutraceutical applications