SCREENING OF Α-Glucosidase INHIBITORS FROM TERMINALIA CATAPPA L. FRUITS USING MOLECULAR DOCKING METHOD AND IN VITRO TEST

Abstract

Objective: Terminalia catappa L. (T. catappa L.) fruit has inhibitory activity on α-glucosidase, therefore, can be a potential natural source for the treatment of type II diabetes mellitus. Inhibitory activity of ethanol fruit extract with IC50 3.02 µg/ml was the strongest inhibition when compared with 54 medicinal plants used as an antidiabetic agent Methods: Molecular docking using AutoDock 4.2 was performed to predict the binding modes of α-glucosidase enzyme from Saccharomyces cereviciae with 13 chemical constituents of T. catappa. α-Glucosidase enzyme was obtained from Protein Data Bank (PDB code: 3A4A). Acarbose, voglibose and miglitol were used as standards. Docking result determines the highest binding energy (ΔG) and inhibition constants (Ki) as an active compound. Visualization of amino acid residues around the active compound was identified with PyMOL and LigPlot. Screening of active compound was carried out by T. catappa L. fruit remaceration extraction use hexane and ethyl acetate. Ethyl acetate extract was separated on silica gel column chromatography using n-hexane, ethyl acetate and methanol sequentially based on polarity of each solvent. Identification of an active compound from ethyl acetate sub fractions using TLC and GC-MS method. The inhibitory activity of the active compound of α-glucosidase was determined with in vitro test using α-glucosidase enzyme.in Indonesia. This project was aimed to find the active compound from T. catappa L. fruit using molecular docking, identification ethyl acetate subfraction using TLC and GC-MC, determine in vitro test on α-glucosidase inhibitory activity from ethyl acetate extract and subfraction. Results:The highest binding energy and inhibition constant is β-sitosterol with ΔG-10.61 kcal/mol and Ki 0.02 µM. The ligand was situated around of 18 amino acid residues. Ethyl acetate subfractions A, B and C showed that subfraction B contains similar spot characteristic and Rf value (0.42) with β-Sitosterol standard. Identification with GC-MS gave β-sitosterol acetate and sitostenone. Redocking process of β-sitosterol acetate and sitostenone showed ΔG-11.14 kcal/mol and-9.79 kcal/mol with Ki 0.01 μM and 0.07 μM respectively. In vitro test of acarbose, ethyl acetate extract and subfraction B gave IC50 Conclusion: Three steroids that are β-sitosterol, β-sitosterol acetate and sitostenone were the active compounds responsible for α-glucosidase inhibitory activity of T. catappa L. fruit. According to the in vitro test, ethyl acetate extract has stronger α-glucosidase inhibitory activity than ethyl acetate subfraction B.17.52; 192.51 and 296.28 µg/ml.

Molecular Docking of Active Compounds Piper crocatum on the A-Glucosidase Enzyme as Antidiabetic

“…Hal ini diperkuat dengan penelitian yang dilakukan oleh Shivanagoudra terhadap ekstrak etil asetat buah melon cina dimana senyawa 25-isopropenylchole-5,(6)-ene-3-O-β-Dglucopyranoside (IDG) yang terkandung didalam ekstrak etil aseat buah melon cina terikat pada residu Leu313, Asp242, Pro312, Val308, Val319 dan His280 di katalitik situs glukosidase. 25 IDG menghasilkan pose docking terbaik dibandingkan senyawa lain, yaitu 25-trihydroxycucurbita-5, 23(E)-dien-19-al (TCD) and charantaB yang diisolasi dari ekstrak etil asetat daun M. Charantina dengan energi ikat minimum -10,58 kkal / mol. Ligan dikelilingi oleh residu katalitik Asp 242 dan interaksi itu mungkin penting untuk penghambatan glukosidase.…”

“…Akarbose dikelilingi oleh 18 residu asam amino sebagai situs aktifnya: Asp69, Tyr72, Tyr158, Phe159, Phe178, Asp215, Val216, Glu277, Glu279, Phe303, Asp307, Thr310, Ser311, Arg315, Asp352, Glu411 dan Arg442. 25 Interaksi yang mengikat dapat mengakibatkan penghambatan enzim. Peningkatan energi ikat meningkatkan simultan dalam energi ikat sehingga menyebabkan akarbose menghambat enzim α-Glukosidase secara kompetiti.…”

Virtual Screening of Heterocyclic Compounds Against Angiotensin-Converting Enzyme for Potential Antihypertensive Inhibitors

“…The 3D structures of all the 10 selected ACE inhibitors were virtually screened to reveal their binding efficiencies through docking in the predicted binding site of ACE using FlexX module of LeadIT. The docking was performed with the default parameters [10][11][12].…”

α-Glucosidase Inhibition Activity of Stem Bark Ceiba pentandra Linn. In Vitro and In Silico

“…Homology modelling quality verified by PROCHECK (Sari et al, 2016). Using MAL32 target sequence and structure with PDB ID 3AJ7 as template, homology modelling of αglucosidase created by SWISS MODEL based on harmony of template of target using ProMod3.…”