DOI: https://doi.org/10.55373/mjchem.v28i5.199

Keywords: Etlingera triorgyalis, Zingiberaceae, phytochemical, acetylcholinesterase, flavanone

Abstract

The genus Etlingera, belonging to the family Zingiberaceae, is widely distributed throughout tropical Southeast Asia and has long been used in traditional medicine for the treatment of fever, inflammation, gastrointestinal disorders, infectious diseases, and wounds. This study focusses on analysing the phytochemicals from Etlingera triorgyalis rhizome extracts and assessing their acetylcholinesterase inhibitory activity. The phytochemicals were obtained using column chromatography techniques and characterised by spectroscopy methods (IR, MS, and NMR) and comparison with literatures. Acetylcholinesterase inhibitory activity was determined using acetylcholinesterase enzyme according to the Ellman colorimetric method. The compounds were extracted by cold extraction with solvents (n-hexane, ethyl acetate, methanol) and isolated by column chromatography. Spectroscopic analyses (IR, MS, and NMR) led to the identification of ten compounds, including pinostrobin (1), hesperetin (2), naringenin (3), vanillin (4), β-sitosterol (5), coniferyl alcohol (6), sinapyl alcohol (7), p-coumaryl alcohol (8), stearic acid (9), and capric acid (10). Compound (3) exhibited the strongest AChE inhibition (IC₅₀ value 45.0 μM), followed by compound (2) (IC₅₀ value 60.8 μM) and compound (1) (IC₅₀ value 85.2 μM), compared with galantamine (IC₅₀ value 2.2 μM). Molecular docking against human AChE (PDB ID: 4EY5) supported the activity of the flavanones, with naringenin, hesperetin, and pinostrobin recording binding scores of -8.514, -7.779, and -7.502 kcal/mol, respectively. In silico ADMET analysis predicted high intestinal absorption for all ten compounds and low mutagenicity probabilities for the three active flavanones. These findings identify the flavanone constituents of E. triorgyalis as promising natural AChE-inhibitory scaffolds for further investigation.