Optimization of the extraction of phenolic compounds from Scirpus holoschoenus using a simplex centroid design for antioxidant and antibacterial applications

- Highest total phenolic content (TPC) of S. holoschoenus was extracted with 70% acetone.
- Three cycles of 1 h extraction procedure was more effective in TPC extraction.
- TPC, tannins and flovoinoids were measured in crude extract and its fractions.
- Ethyl acetate fraction showed the highest antioxidant and antibacterial activities.
- Petroleum ether fraction affected negatively the antibacterial activity of samples.

A simplex-centroid mixture design (SCMD) approach was used to select the best solvent for the extraction of the phenolic compounds from Scirpus holoschoenus L. rhizome. The optimized crude acetone extract (CE) and its ethyl acetate (EA) and petroleum ether (PE) fractions were investigated for their antioxidant and antibacterial properties. The EA fraction showed the highest antioxidant activity and antibacterial effect, with minimal inhibitory concentration (MIC) values of 0.4 and 0.6 mg mL−1 for Staphylococcus aureus and Bacillus subtilis, respectively. The antibacterial activity was evaluated by SCMD and the results indicated that antagonist binary extract effects between the PE-EA and PE-CE pairs are found.