Abstract

Etlingera rubroloba is a traditional medicinal plant in Southeast Sulawesi, Indonesia. To date, no studies have been reported on the chemical and pharmacological aspects of E. rubroloba rhizomes. The total secondary metabolites of the methanol extract of E. rubroloba rhizome was analysed, by using the UPLC-High-Resolution Mass Spectrometry (HRMS) technique. It involves the isolation and structural elucidation of major compounds through chromatographic and spectroscopic methods, as well as an evaluation of the biological activities of the extracts and compounds, including antioxidant, anti-inflammatory, and antidepressant effects (the latter tested in silico). Six major compounds were identified for the first time from this species: Stigmasterol (ER1), Stigmast-4-en-6β-ol-3-one (ER2), Yakuchinone A (ER3), 1-(3’-methoxy-4’-hydroxyphenyl)-7-(4’’-hydroxyphenyl)-3-heptanone (ER4), 3,5-dimethoxy-4-acetoxy cinnamic alcohol (ER5), and p-Coumaric acid (ER6). The diarylheptanoids (ER3 and ER4) exhibited superior antioxidant activity, while the steroids (ER1 and ER2) demonstrated strong anti-inflammatory effects. Additionally, docking simulations suggested that ER1 and ER2 exhibited low binding energies towards monoamine oxidase, dopamine transporter, and serotonin transporter, indicating a possible relevance to neurotransmission pathways associated with depression. These findings highlight the chemical composition and pharmacological potential of E. rubroloba rhizomes, marking the first report of their antioxidant, anti-inflammatory, as well as their potential to interact with targets associated with depression, which represents a promising avenue for further confirmation through in vitro studies.

Key words: Etlingera rubroloba; secondary metabolites; antioxidant, anti-inflammatory, antidepressant