Antioxidant and anti-inflammatory activities and bioactive compounds of the leaves of Trichodesma khasianum clarke

Abstract

Trichodesma khasianum (T. khasianum) Clarke, a native edible plant, is considered to have effective biological activity. However, the scientific evidence behind its bioactivity and health benefits remains unclear. This study aimed to investigate the bioactive compound, antioxidant, and anti-inflammatory effects of T. khasianum Clarke leaves. Higher levels of phenolics and flavonoids with potent oxygen radical absorbance capacity (ORAC) and Trolox equivalent antioxidant capacity (TEAC) were observed in the 80 % ethanol extract (named 80EETC) of T. khasianum Clarke leaves. The bioactive compound rosmarinic acid (RA) was identified in the 80EETC by high-performance liquid chromatography (HPLC) and Q Exactive Focus liquid chromatography–high-resolution mass spectrometry (LC–HRMS). The 80EETC showed a dramatic anti-inflammatory effect in suppressing inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression, consequently reducing downstream nitric oxide (NO) and prostaglandin E2 (PGE2) levels in lipopolysaccharide (LPS)-induced RAW264.7 cells. In conclusion, the antioxidant and anti-inflammatory effects of T. khasianum Clarke leaves were demonstrated, and RA was identified as a major bioactive compound. This novel finding might demonstrate a potential application of this plant as a functional food.