Antioxidant, antibacterial, and anti-inflammatory activities of standardized brazilin-rich Caesalpinia sappan extract

摘要

Context: Brazilin is a major active principle of Caesalpinia sappan L. (Leguminosae or Fabaceae). For industry aspects, brazilin-rich extract (BRE) has been prepared and standardized to contain 39% w/w brazilin. BRE may have more advantages than brazilin in term of a lower-cost production process.Objectives: To investigate the antioxidant, antibacterial, and anti-inflammatory activities of BRE.Material and methods: BRE was prepared by a simple one-step purification of the crude ethanol extract of C. sappan heartwood (CSE) using a Diaion? HP-20 column. The antioxidant activities were determined using three methods, including DPPH radical scavenging, reducing power, and β-carotene bleaching assays, at concentration ranges of 1–10, 10–100, and 10–100?μg/mL, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of BRE (15.6–1000?μg/mL) against Gram-positive and Gram-negative bacteria were determined by the broth microdilution method. Anti-inflammatory activity of BRE (0.1–5?μg/mL) was evaluated as anti-denaturation activity using bovine serum albumin as a substrate.Results and discussion: On the basis of β-carotene bleaching assay, BRE showed antioxidant activity with an EC₅₀ value of 60.5?μg/mL, which was almost equal to that of pure brazilin (52.1?μg/mL). Gram-positive bacteria were more sensitive to all tested samples than Gram-negative bacteria. BRE possessed higher antibacterial activities than CSE, but lower than brazilin. MIC/MBC values of 62.5–125/125 and 250–500/250–500?μg/mL were obtained for BRE against Gram-positive and Gram-negative bacteria, respectively. A low concentration (0.1?μg/mL) of brazilin, BRE, and CSE showed anti-inflammatory activity by inhibiting protein denaturation up to 46.8, 54.1, and 61.9%, respectively.