Response surface methodology applied to subcritical solvent extraction of brazilin compound from Caesalpinia sappan L. heartwood

Abstract

Subcritical solvent extraction technique could be used to extract brazilin from Caesalpinia sappan L. heartwood (CSH). The optimal experimental condition for the subcritical solvent extraction, simultaneously giving the highest percentage yield of dried crude extract sample (9.95%), maximal brazilin content (84.65 mg/g dry heartwood), the lowest IC50 values of DPPH and ABTS scavenging activities (11.42 and 8.62 μg/mL extract, respectively) and the highest FRAP value (12.11 μM FeSO4 equivalents/100 μL extract) of the CSH extract were obtained using ethanol: water (3:1 w/w) as the solvent and a solvent: CSH ratio of 9:1 (w/w) at 100 °C for 50 min. Under this optimal extraction condition, the heartwood extract exhibited antibacterial activity against bacteria which had the minimal inhibitory concentration and minimum bactericidal concentration values of 0.98 and 1.45, 1.96 and 2.94, 3.91 and 3.91, and 3.91 and 3.91 mg/mL to inhibit and kill Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Escherichia coli, respectively. The obtained data might substantiate the potential health benefits of the crude extract and brazilin compound of Caesalpinia sappan L. heartwood, as potential natural antioxidant and antimicrobial ingredients in food, food supplements, cosmetic and pharmaceutical production, and, also, as food preservatives or coloring agents in the food processing industries.