Optimization of Ultrasound-Assisted Extraction of Anthocyanin from Erythrina crista-galli Flowers

Anthocyanins are hydrophilic plant pigments from the flavonoid group that offer health benefits. Erythrina crista-galli is one such anthocyanin-containing plant. The ultrasound-assisted extraction (UAE) technique enhances anthocyanin extraction efficiency while reducing solvent use (e.g. ethanol or methanol) and extraction time compared to conventional methods. The effectiveness of UAE for anthocyanin extraction depends on factors such as temperature, solvent concentration, and solid-liquid ratio. This study aims to optimize the extraction of anthocyanins from E. crista-galli using UAE with RSM. The optimized UAE conditions were obtained using 68.71 % ethanol acidified with 1 % citric acid, an extraction time of 30 min, a temperature of 48.15 °C, and a solid-liquid ratio of 0.0435 g/mL. LC-MS/MS-based metabolite profiling identified five anthocyanins in E. crista-galli flowers, namely cyanidin-3-glucoside, cyanidin-3,5-diglucoside, pelargonidin 3,5-diglucoside, pelargonidin 3-glucoside, and pelargonidin-3-sambubioside. The in vitro antioxidant assay showed that E. crista-galli extract exhibited an IC₅₀ value 380.44 ± 4.13 ppm. Additionally, the extract demonstrated significant antibacterial activity against E. coli and S. typhimurium. HIGHLIGHTS It is the first to explore Optimization of Ultrasound-Assisted Extraction of Anthocyanin from Erythrina crista-galli We employed a LC-MS/MS to identify the presence of anthocyanin in the extract of crista-galli flowers. The anthocyanin extract from crista-galli flowers exhibited antioxidant activity with an IC50 value of 380.44 ± 4.13 ppm. On the other hand, the anthocyanin extracts exhibited significant antibacterial activity against E. coli and Salmonella thypimurium. GRAPHICAL ABSTRACT