Inhibitory Activity of Aralia elata Leaves on Protein Tyrosine Phosphatase 1B and α-Glucosidase

참두릅 잎의 Protein Tyrosine Phosphatase 1B와 α-Glucosidase 저해 활성

Anti-diabetic potential of the leaves of A. elata through the inhibitory activity on PTP1B and ${\alpha}$-glucosidase has not been reported. In this study, the EtOAc fraction of methanolic extract from the leaves of A. elata showed potent inhibitory activity against the PTP1B and ${\alpha}$-glucosidase with $IC_{50}$ value of $96.29{\pm}0.3$ and $264.71{\pm}14.87{\mu}g/mL$, respectively. Three known triterpenoids, oleanolic acid, oleanolic acid-28-O-${\beta}$-D-glucopyranoside and oleanolic acid-3-O-${\beta}$-D-glucopyranoside were isolated from the most active EtOAc fraction. We determined the chemical structure of these triterpenoids through comparisons of published nuclear magnetic resonance (NMR) spectroscopic data. Furthermore, we screened these triterpenoids for their ability to inhibit PTP1B and ${\alpha}$-glucosidase over a range of concentrations ($12.5-50{\mu}M$). All three terpenoids significantly inhibited PTP1B in a concentration dependent manner and oleanolic acid effectively inhibited ${\alpha}$-glucosidase. In addition, these compounds revealed potent inhibitory activity with negative binding energies toward PTP1B, showing high affinity and tight binding capacity in the molecular docking studies. Therefore, the results of the present study clearly demonstrate that A. elata leaves and its triterpenoid constituents might be beneficial in the prevention or treatment of diabetic disease.