Phytochemical profiles and evaluation of free radical scavenging activities of Cassiasieberiana using 1,1-diphenyl-2-picryl hydrazyl and2,2′ -Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)

Abstract

Cassia sieberiana is used in traditional medicine in West Africa, including Nigeria. This study evaluated the phytochemical profile and free radical scavenging activities of C. sieberiana root bark extracts (weighing 100 g). The powdered root bark was extracted with petroleum ether, methyl acetate, acetone, chloroform, methanol (MeOH), and 70% MeOH using a Soxhlet extractor, and the resulting extracts were concentrated under reduced pressure. Methyl acetate, MeOH, and 70% MeOH extracts were analyzed qualitatively and quantitatively using standard phytochemical methods, and their antioxidant activities were assessed using 1,1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2-azinobis-ethyl benzothiozoline-6-sulphonic acid (ABTS) assays. Qualitative analysis indicated the presence of saponins, quinones, phenols, steroids, tannins, flavonoids, terpenoids, anthraquinones, cardiac glycosides, alkaloids, carbohydrates, glycosides, and coumarins in the extracts. The highest contents of flavonoids, phenolics, tannins, saponins, steroids, and alkaloids were recorded in methyl acetate (38.74 µg QE/g), MeOH (259.78 µg GAE/g), methyl acetate (228.67 µg TAE/g), MeOH (961.88 µg DE/g), 70% MeOH (108.08 µg βSSE/g), and 70% MeOH (1.81 µg CE/g), respectively. The extracts showed substantial free radical scavenging activities, with IC50 values of 30.19 µg/mL for the methyl acetate extract in the DPPH assay and 15.20 µg/mL for the methyl acetate extract in the ABTS assay. These findings support the antioxidant potential of C. sieberiana root bark and its possible value as a source of natural antioxidants.