Selective aqueous-based recovery of curcuminoids, ferulic acid and starch from turmeric (Curcuma longa L.) powder and their antibacterial activities

Turmeric (Curcuma longa L.) is a widely recognised as medicinal plant valued for its bioactive components, particularly curcuminoids and ferulic acid, which exhibit strong antioxidant, anti-inflammatory, and therapeutic properties. In this study, a selective aqueous-based extraction method was developed for the simultaneous recovery of curcuminoids, ferulic acid, and starch from turmeric powder. Optimal extraction conditions (10% w/v NaOH, 80 °C, 4 h) enabled efficient fractionation, with methanol effectively preserving curcuminoids. The identity and purity of the isolated compounds were confirmed by spectroscopic analysis. Quantitative analysis showed curcumin recovery of 0.50%–4.10% and ferulic acid recovery of 1.40%–1.95% from turmeric samples. Antibacterial testing revealed dose-dependent activity for both curcumin and ferulic acid against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus arlettae. Ferulic acid displayed strong inhibition against S. arlettae and B. cereus, but weaker effects against E. coli and P. aeruginosa, while curcumin showed moderate activity.