Nootchanat Mairuae¹ , Benjaporn Buranrat¹, Supataechasit Yannasithinon¹, Poonlarp Cheepsunthorn²

Abstract

Purpose: To investigate the antioxidant and anti-inflammatory effects of Oroxylum indicum (L.) Kurz leaf extract on lipopolysaccharide (LPS)-activated BV2 microglia. Methods: BV2 cells were treated with LPS for 24 h in the presence or absence of Oroxylum indicum (O. indicum) leaf extract. The levels of reactive oxygen species (ROS), nitric oxide (NO), and interleukin 6 (IL-6) were quantified with CM-H2DCFDA, Griess reagent assay, and enzyme-linked immunosorbent assay (ELISA) test, respectively. The antioxidant activity of O. indicum leaf extract was assessed in vitro using DPPH, ABTS and FRAP assays. Results: Treatment with LPS resulted in significant increases in the levels of ROS, NO, and IL-6, when compared to untreated cells. However, co-treatment with O. indicum leaf extract significantly suppressed the production of these inflammatory markers (p < 0.05). In addition, the leaf extract of O. indicum exhibited antioxidant activity in the DPPH, ABTS, and FRAP assays. The contents of flavonoids and phenolics in O. indicum leaf extract were 13.25 ± 0.163 mg QE/g of dried extract and 82.58 ± 1.772 mg QE/g of dried extract, respectively (p < 0.05). Conclusion: The leaf extract of O. indicum exhibits anti-inflammatory and antioxidant properties in LPS-activated BV2 cells. This finding indicates that the leaf extract of O. indicum has promising potentials as a new source of herbal medication with anti-inflammatory properties. However, there is a need for more studies to unravel the fundamental mechanisms of their actions.