Galloylated Phenolics from Indian Gooseberry ( <i>Phyllanthus emblica</i> L.) and Their Protein Tyrosine Phosphatase 1B (PTP1B) Inhibition

Indian gooseberry (<i>Phyllanthus emblica</i> L.) fruits are traditionally consumed for their nutritional value and diverse medicinal properties. In this study, the ethanol extract of the fruits exhibited potential effects on the inhibition of protein tyrosine phosphatase 1B (PTP1B). Two novel galloylated phenolics (<b>1</b> and <b>2</b>) and nine known compounds (<b>3</b>-<b>11</b>) were isolated and structurally identified. The absolute configurations of new compounds were determined using spectroscopic analyses, Mosher's ester method, and quantum chemical calculations. PTP1B inhibitory activities of compounds <b>1</b>-<b>10</b> were evaluated, with compound <b>10</b> exhibiting the strongest inhibition (IC₅₀ = 16.3 μM), whereas other compounds did not show inhibitory activity at concentrations up to 80 μM. Kinetic analysis revealed compound <b>10</b> as a mixed inhibitor, and molecular docking provided insights into its interaction with PTP1B. This is the first time that the PTP1B inhibition of galloylated phenolics from <i>P. emblica</i> fruit was reported. Our findings suggest Indian gooseberry fruits as a promising source of bioactive phenolics for developing PTP1B inhibitors with potential antidiabetic properties.