Phytochemical Analysis and Antioxidant Activity of Extracts from Berchemia zeyheri — A Swazi Medicinal Plant

Berchemia zeyheri_ belongs to the Rhamnaceae family_. B. zeyheri_ has been used in the traditional medicine to treat various ailments, which include backache, cough, diarrhea, dysentery, headache, rectal ulcers, gastrointestinal issues and vomiting. The objectives of the present study were to analyze phytochemical constituents, to evaluate the antioxidant activity and to determine IC50 values of hexane, chloroform, ethyl acetate, acetone, and methanol crude extracts obtained separately from the leaves and stem-bark of B. zeyheri. Qualitative of phytochemical analysis was performed by using established methods and procedures. Various solvent extracts were obtained by means of maceration and hot solvent extraction techniques. The assessment of antioxidant activity and the determination of half-maximal inhibitory concentration (IC50) values were achieved by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The presence of alkaloids, steroids, terpenoids, phenolics, tannins, flavonoids, coumarins, saponins, glycosides, carbohydrates, proteins and phlobatannins were identified in these extracts. In the DPPH assay, the positive control (ascorbic acid) showed a radical scavenging activity of 87. 84±0. 01 at a concentration of 3000 µg/mL. The ethyl acetate extracts obtained from leaves and stem-bark exhibited highest radical scavenging activity of 67. 91±0. 01% and 70. 22±0. 01%, respectively at a concentration of 3000 µg/mL, whilst hexane extracts obtained from leaves and stem-bark showed least radical scavenging activity of 48. 88±0. 04 % and 49. 19±0. 01%, respectively at the same concentration. The IC50 value of ascorbic was found to be < 200 µg/mL in the DPPH assay. On the other hand, the methanol and hexane extracts obtained from leaves showed IC50 values of 1513. 30 and 2759. 00 µg/mL µg/mL, respectively which were the lowest and highest IC50 values among the extracts from leaves. Similarly, the ethyl acetate and hexane extracts obtained from stem-bark showed IC50 values of extracts 1228. 59 and 2647. 28 µg/mL, respectively which were the lowest and highest IC50 values among the extracts from stem-bark. From this study, we conclude that various extracts obtained from the leaves of stem-bark of B. zeyheri_ possessed various classes of phytochemicals and these extracts showed a weak to moderate radical scavenging activity. Further studies on this plant are required to explore its therapeutic applications.