Flavanones from Ethyl Acetate Fraction of Caesalpinia sappan Heartwood as Anti-Inflammatory and Antioxidant: Isolation, In-vitro, and In-silico approach

Caesalpinia sappan, commonly known as secang by Indonesian people, has been widely used for its analgesic, antioxidant, anti-diabetes, anti-inflammatory, anti-microbial, and anticancer activities. Flavonoids are reported as the most responsible constituents for those pharmacology effects. Flavanone, one of the flavonoid classes, has a particular interest because it has a wide range of compounds with O-substituents, such as hydroxy, methoxy, and O-glycosyl. In this study, the isolation of constituents in C. sappan was carried out by MeOH extraction, followed by solvent partition using ethyl acetate. Continuing the purification of ethyl acetate fraction with SiO2 column chromatography gave 9 sub-fractions (A1-A9). Analysis of antioxidants suggested that A7, A6, and A5 have the highest antioxidant activities. An anti-inflammatory test was carried out in-vitro using RAW 264.7 cell macrophage to evaluate the suppression of nitric oxide (NO) induced by LPS. Fractions A3, A6, and A7 are giving promising results in the suppression of NO production. Further analysis using LC-MS to these fractions gave poriol and pinostrobin (flavanone derivatives) and hydroxybrazilin consist in fractions A3, A5, A6, and A7. In-silico analysis by molecular docking revealed that pinostrobin and poriol show a better result to inhibit iNOS, COX-1, COX-2, IL-1β, and TNF-α as inflammatory mediators dan inflammatory cytokines. The hydroxyl group from poriol and pinostrobrin is responsible for their antioxidant activities, while the methoxy group in pinostrobin can increase its anti-inflammatory activity shown by the better binding affinity. Taken together, the result suggests that the flavanones from C. sappan have potent antioxidant and anti-inflammatory activities that are prospective for future drug development.