Antioxidant Potential of Calophyllum canum P. F. Stevens: Xanthones, Phenolics, and Radical Scavenging Activity

Abstract

The isolation and purification of the ethyl acetate of C. canum stem bark have yielded a new α,β-unsaturated δ-lactone compound, canumolactone (8), along with known xanthones, 1-hydroxy-7-methoxyxanthone (1), caloxanthone C (2), trapezifolixanthone (3), ananixanthone (4), euxanthone (5), gentisin (6), 2-hydroxyxanthone (7), and α-mangostin (9). In this study on C. canum extracts, the total phenolic content (TPC), total flavonoid content (TFC), and radical scavenging activity (RSA) were investigated to assess the antioxidant potential. The extraction of C. canum stem bark yielded various crude extracts, with the ethyl acetate extract showing the highest RSA (97.14 ± 0.24 %) and TPC (277.33 ± 9.65 mg GAE/g extract). The TFC values varied across extracts, with the dichloromethane extract displaying the highest TFC (117.96 ± 3.35 mg QE/g extract). A strong positive correlation was observed between TPC and RSA, indicating the significant role of phenolic compounds in the antioxidant activity of the extracts. Conversely, the relationship between TFC and RSA was weak, suggesting a minor contribution of flavonoids to the antioxidant potential of the extracts. These findings highlight the importance of phenolic compounds in determining the antioxidant activity of C. canum extracts.