Three Polyphenols Isolated from Ochna integerrima Flowers and their Inhibitory Effects on Nitric Oxide Synthesis

Background: Ochna integerrima (Lour.) Merr., commonly known as "Mai Vàng," is a flowering plant native to Southeast Asia. The plant contains various flavonoids, contributing to its medicinal properties, including antioxidant and anti-inflammatory effects. However, the understanding of its chemical components is limited. This study aimed to isolate compounds from ethyl acetate (EtOAc) extract and evaluated their NO inhibitory activities. Methods: The structures of isolates were clarified using nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analyses, and they were compared with previously published spectral data. The Griess assay was performed to evaluate the anti-inflammatory activity of isolated compounds in LPS-stimulated RAW 264.7 cells. Results: Six compounds (1-6) were obtained from the EtOAc extract, including 2,4- dihydroxyphenylacetate (1), (+)-catechin (2), luteolin (3), apigenin (4), vitexin (5), and cynaroside (6). Among them, compounds 1 and 2 exhibited significant NO inhibitory activity against LPS-stimulated RAW.264.7 cells without any cytotoxicity. Compounds 1, 4, and 6 were first reported from this species. Conclusion: This species holds promise as a potential candidate for its anti-inflammatory effects.