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

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.