This study investigated the flavonoid content, antioxidant activity, and toxicological properties of the acetone-water fraction of stem bark of Stryphnodendron rotundifolium Mart. (TFSR). The total flavonoid content and antioxidant activity were determined, as typified by DPPH● and ABTS●+ radical scavenging abilities, Fe3+ reducing antioxidant power (FRAP), relative antioxidant capacity (RAC), and the inhibition of thiobarbituric acid reactive species (TBARs) in Drosophila melanogaster tissue. Toxicity and locomotor functions were evaluated in adult D. melanogaster flies through aging and survival assays, startle-induced negative geotaxis, and centrophobic responses with video-assisted open field motion tracking. The flavonoid content of dry TFSR (DF) was 3.36 mg quercetin/g. Furthermore, the significant antioxidant activity of TFSR was revealed through scavenging 95.3% of the ABTS●+ radical and 82.4% of the DPPH● radical, as well reducing 74.7% of Fe3+ in the FRAP assay and 80% Mo6+ in the RAC assay. TFSR conferred 70.25% protection against lipid peroxidation in Drosophila tissue. Survival rates ranged from 84.65 to 103.98% in comparison to the non-supplemented control and no evident deterioration of locomotor functions and centrophobia responses was observed. These results revealed that TFSR has potent antioxidant activity and low toxicity in vivo, profiling TFSR as a promising natural product in the treatment/management of iron overload and associated conditions.
Keywords: Stryphnodendron rotundifolium Mart.; antioxidant activity; iron overload protection.