Extracts of three leaves: Cymbopogon citratus, Hibiscus sabdariffa, and Lawsonia inermis were screened for phytochemicals in ethanol (80%), hexane, and ethyl acetate. The potential of plant extracts to scavenge free radicals such as DPPH, ABTS and FRAP (Ferric Reducing Antioxidant Power) was investigated.
For all extracts, phytochemical analysis indicated the presence of terpenoids, steroids, tannins, anthocyanins, phenols and flavonoids with absence of fatty acids in ethanol 80% and ethyl acetate.
Ethyl acetate extract of L. inermis achieved a high percentage of TPC and TFC, but it was higher in 80% ethanol of H. Sabdariffa than the other extracts under study. Ethyl acetate extracted the highest TPC (66.8 ± 3.6 mg/100g) in C. citratus and 80% ethanol extracted the highest TFC (37.23± 2.05mg/100g.
Ethanolic extract (80%) of the three plants' leaves showed a higher IC50 value than both ethyl acetate and hexane extracts. This indicates that 80% ethanol was the best solvent for extracting phenolic compounds and flavonoids.
The “ABTS radical" scavenging activity was the highest for ethyl acetate extract of L. inermis. The lowest value was observed for hexane extract of both C. citratus and L. inermis.
This study exhibited potential of ethanolic extracts (80%) of all plants for removing free radicals and their effectiveness to be a powerful antioxidant.