antioxidant activity and phytochemical analysis of extracts from acacia gerrardii: a medicinal plant from the kingdom of eswatini

Acacia gerrardii has been used in the treatment of cough, enema, haemorrhage, rheumatism, stomach pain, swelling, and infections due to emetic and upper respiratory system. the objectives of current study were to evaluate 2,2-diphenyl-1-picrylhydrazyl (dpph) radical scavenging potential and determine the half-minimal inhibition concentration (ic50) values of various solvent extracts obtained from leaves and stem-bark of a. gerrardii. in addition, these extracts were also subjected to phytochemical analysis for the identification of various classes of compounds. the maceration and hot solvent extraction techniques were used to obtain hexane, chloroform, ethyl acetate, acetone, and methanol extracts separately from leaves and stem-bark of a. gerrardii. dpph radical scavenging assay was employed to evaluate radical scavenging potential and determine ic50 values of these extracts. phytochemical analysis of these extracts was performed using established methods described in literature. ascorbic acid served as positive control, which showed radical scavenging potential in the range of 38.19±0.01-78.13±0.03% at 200-3000 µg/ml. the radical scavenging potential of various solvent extracts obtained from leaves was found to be in the ranges of 4.17±0.02-44.66±0.07%, 6.48±0.05-49.54±0.02%, 9.84±0.04-52.46±0.01%, 6.28±0.02-60.53±0.05%, and 8.44±0.03-63.97±0.03%, respectively, 200-3000µg/ml. similarly, the radical scavenging potential of various solvent extracts obtained from stem-bark was found to be in the ranges of 0.21±0.14-55.17±0.01%, 21.67±0.05-57.88±0.02%, 24.89±0.64-64.39±0.01%, 19.11±0.04-58.54±0.04% and 33.48±0.15-66.17±0.01%, respectively, at 200-3000µg/ml. furthermore, the ic50 values of positive control, extracts from leaves and extracts from stem-bark were determined to be 562.87 µg/ml, ˃3000, ˃3000, 2623.87, 2305.80, 2071.95, 2484.36, 2015.70, 1643.07, 1937.91, and 1335.27 µg/ml, respectively. the following classes of phytochemicals viz. alkaloids, steroids, terpenoids, phenolics, tannins, flavonoids, coumarins, saponins, glycoside, carbohydrates, proteins, and phlobatannis were identified in these extracts. from this study, we concluded that a. gerrardii exhibited moderate to significant dpph radical scavenging potential and possessed various classes of phytochemicals.