CHEMICAL CHARACTERIZATION AND FREE RADICAL SCAVENGING ACTIVITY OF DENDROBIUM THONGCHAI EXTRACTS: A PROMISING SOURCE FOR NEUROPROTECTIVE AND ANTIMICROBIAL AGENTS.

Abstract

Background: Bioactive compounds with medical applications can be found in orchids. Despite commercial cultivation, Dendrobium thongchai (gold) remains unstudied scientifically. This study aimed to determine its phytochemical profile and antioxidant activity. Methods: Root samples were macerated using methanol and ethanol, and analyzed by gas chromatography–mass spectrometry (GC–MS). Antioxidant capacity was measured using ferric reducing antioxidant power (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. Results: GC–MS analysis identified 45–50 compounds, including indole derivatives, fatty acid esters, alkaloids, and glycosides, known for antimicrobial and neuroprotective properties. Antioxidant assays showed significant free radical scavenging and reducing activity, with ethanol extracts performing better than methanol due to higher phenolic content. Comparative analysis confirmed solvent polarity as crucial for antioxidant efficacy. Conclusion: This first comprehensive study of D. thongchai's phytochemistry and bioactivity positions it as a promising source of natural products with therapeutic potential. Further biological research and structural validation are needed for therapeutic applications.

Keywords : Dendrobium thongchai, GC–MS, antioxidant activity, indole derivatives, phenolics, neuroprotection, antimicrobial.