Biological evaluation of gallic acid and quercetin derived from<i>Ceriops tagal</i>: insights from extensive<i>in vitro</i>and<i>in silico</i>studies

Abstract

Gallic acid (PubChem CID: 370) and quercetin (PubChem CID: 5280343) are major phenolic compounds in many mangrove plants that have been related to health cure. In the present study, the active fractions namely gallic acid (<b>1)</b> and quercetin (<b>2)</b> were isolated from the methanolic extract of leaves of <i>Ceriops tagal</i> in a Tropical mangrove ecosystem of Andaman and Nicobar Island (ANI), India. The chemical structures were determined by spectroscopic analysis: Fourier-Transform Infrared spectroscopy (FT-IR), ¹H, ¹³C Nuclear Magnetic Resonance (NMR) spectroscopy, and High-resolution mass spectrometry (HRMS). The anticancer activity of isolated compounds (<b>1)</b> and (<b>2)</b> were evaluated by <i>in vitro</i> assays against two human cancer cell lines namely, HeLa (Cervical) and MDA-MB231 (Breast) cancer cells revealed that IC₅₀ values of gallic acid (HeLa: 4.179197 ± 0.45 µg/ml; MDA-MB231: 80.0427 ± 0.19 µg/ml at 24 h) and quercetin (HeLa: 99.914 ± 0.18 µg/ml; MDA-MB231: 18.288382 ± 0.12 µg/ml at 24 h), respectively. Antioxidant properties of gallic acid (<b>1</b>) and quercetin (<b>2</b>) are found to be IC₅₀ value of 0.77 ± 0.41 µg/ml and 1.897 ± 0.81 µg/ml, respectively. Molecular docking results explained that gallic acid (<b>1</b>) and quercetin (<b>2</b>) showed estimated binding free energy (<i>ΔG</i>) of -5.4 and -6.9 kcal/mol towards drug target Bcl-B protein, respectively. The estimated inhibition constant (<i>Ki</i>) for these two molecules are 110 and 8.75 μM, respectively. The MD simulation additionally supported that quercetin molecule is significantly improved the structural stability of Bcl-B protein. The present study provides key insights about the importance of polyphenols, and thus leads to open the therapeutic route for anti-cancer drug discovery process.Communicated by Ramaswamy H. Sarma.