RAPID ANALYSIS OF ALPHA-GLUCOSIDASE INHIBITORY ACTIVITY OF PSYCHOTRIA MALAYANA JACK LEAF APPLYING INFRARED FINGERPRINTING

Abstract

Psychotria malayana Jack is the plant belongs to Rubiaceae family and known in Malaysia as “meroyan sakat/salung”. Despite its potential use as an antidiabetic agent, a rapid analytical approach for the quality control of this plant has not been developed. Thus, the objective of this study was to establish a validated analytical method for the prediction for the alpha-glucosidase inhibitory activity of the leaves of P. malayana through implementation of Fourier Transformation Infrared Spectroscopy-fingerprinting utilizing a multivariate statistical calculation, orthogonal partial least square. The dried extracts prepared with different solvents ratios of methanol-water (0, 25, 50, 75, and 100% v/v), were evaluated for the bio-activity and analyzed via infrared spectroscopy. Orthogonal partial least square was accomplished through correlating the bioactivity and infrared spectra of every extract. The 100% methanol extract possessed the highest inhibitory activity against the alpha-glucosidase (IC₅₀ 2.83 ± 0.32 ?g/mL). The loading plot from the statistical calculation revealed several functional groups, including hydroxyl (O-H), alkenyl (C=C), methylene (C-H), carbonyl (C=O), and secondary amine (N-H) groups, which actively induced the ?-glucosidase inhibitory activity. The established validated model can be utilized in predicting the inhibitory activity of new set of P. malayana Jack leaves and can also be used as an assessment tool in the quality control of this plant.

Acknowledgments: Tanzina Sharmin Nipun would like to thank the Bangabandhu Science and Technology Fellowship Trust, Ministry of Science and Technology of Bangladesh for the granting of her Ph.D. fellowship. A. Khatib acknowledges the Malaysian Ministry of Education for the Fundamental Research Grant Scheme [FRGS-19-0880697].