Assessment of bioactive compounds and antioxidant properties of Schumannianthus dichotomus Roxb. obtained via a microwave-assisted extraction method

This study focuses on assessing the bioactive compounds, particularly regarding their antioxidant capabilities. The research utilized microwave-assisted extraction (MAE) to obtain 80 % ethanolic and aqueous extracts from the leaves, offshoots and rhizomes of Schumannianthus dichotomus Roxb. A phytochemical analysis was conducted on the three extracts to identify secondary metabolites, including alkaloids, flavonoids, phenolics, glycosides, phytosterols and tannins. Total phenolic content was assessed using the Folin-Ciocalteu method, whereas the total flavonoid content was measured employing the aluminium chloride colorimetric technique. Concurrently, the antioxidant capacity was evaluated utilizing DPPH, ABTS and FRAP assays. The results revealed that all plant extracts demonstrated the presence of phenols, flavonoids, glycosides and phytosterols. The leaves extracted with 80 % ethanol yielded the greatest amount of phenolics, recorded at 2.797 ± 0.117 mg GAE/g sample, while the aqueous extract of the leaves had the highest concentration of flavonoids, measuring 0.544 ± 0.062 mg CE/g sample. Additionally, the most antioxidant activities, particularly for DPPH and ABTS, were obtained in the 80 % ethanol extract from the rhizomes, exhibiting trolox equivalent values of 0.212 ± 0.003 and 2.044 ± 0.031 mg TE/g sample, respectively. Meanwhile, the highest reducing power was observed in the 80 % ethanol extract from the offshoots, measuring 3.864 ± 0.292 mg TE/g sample. Findings also indicated a strong positive correlation between TPC and FRAP, closely followed by the correlation between TPC and DPPH. The findings suggest that S. dichotomus is a reliable source of antioxidant qualities, highlighting its potential use in treating many disorders, especially those associated with oxidative stress.