Phytochemical studies, in vitro antioxidant and antiproliferative of the stem bark of Boswellia dalzielii hutch

Abstract

This work aims to evaluate the total phenolic and flavonoid contents, and antioxidant and Antiproliferative activities of the stem bark of Boswellia dalzielii. Hundred gram (100 g) of methanolic extract was re-dissolved in 70% methanol and partitioned exhaustively with different solvent hexane and ethyl acetate in a separating funnel; and this method gave three fractions, hexane fraction, ethyl acetate fraction and aqueous extract. The ethyl acetate fraction was subjected to Accelerated Gradient Chromatographic due to its higher activity over the hexane fraction and four sub-fractions were obtained. Standard methods were used to determine flavonoid and phenolic contents of the methanolic, aqueous, ethyl acetate and hexane fractions and their sub-fractions. Standard methods were used to determine flavonoid and phenolic contents of the methanolic, aqueous, ethyl acetate and hexane extracts and their sub-fractions. The antioxidant property of the extracts was determined using DPPH radical scavenging and FRAP assay. Growth inhibitory activity was carried out on the crude extracts and sub-fractions using Sorghum bicolor seeds. The phenolic content was found to be highest in sub-fraction C (481.20 ± 10.13 mg GAE/g) and flavonoid contents were found to be highest in methanolic extract (142.17 ± 4.82 mg RE/g). Boswellia dalzielii stem bark exhibited antioxidant capacity; and the highest antioxidant activities were recorded from aqueous extract with the IC50 1.58 and methanol extract IC50 1.99 using DPPH. FRAP assay exhibited antioxidant capacity with EC50 1.00 for aqueous extract and sub-fraction D EC50 1.25. The antiproliferative, sub-fractions C and D at 125 µg/ml gave the highest percentage of inhibition (90%) followed by sub-fraction B (50%) at 250 µg/ml. These results further showed that the stem bark of Boswellia dalzielii has antioxidant activities and antiproliferative activity on the seeds of Sorghum bicolor; and therefore possess likely an anticancer component which needs further anticancer screening