Inhibitory Effect of Methanol Extract of Magnolia officinalis on Matrix Metalloproteinase-2

Matrix metalloproteinase-2 (MMP-2) is a key enzyme involved in tumor invasiveness. The plant of Magnolia officinalis Rehd. et Wils. is often included as an ingredient in various herbal remedies recommended for cancer theraphies in Korea. Various extracts prepared from stems of M. officinalis were tested for cytotoxic activity on human hepatocellular carcinoma cell line, SK-Hep cells using the XTT assay method. Then, the inhibitory effect was examined on MMP-2 activity using gelatin zymography. Methanol (MeOH) extract of M. officinalis caused the strongest inhibition of the MMP-2 activity, as measured by gelatin zymography method for enzyme activity. $IC_{50}$ values of fractions on MMP-2 activity were in a range of $4.9{\sim}11.3\;{\mu}g/mL$. Among each fraction, butanol and ethylacetate (EtOAc) fractions showed the strong inhibitory activities ($IC_{50}=10.7\;and\;4.9\;{\mu}g/mL$, respectively). When the M. officinalis's constituents such as magnolol, honokiol, (-)-epigallocatechin gallate (EGCG) and ovovatol were examined for inhibitory effects on MMP-2 activity, EGCG showed strong inhibitory activity. However, MeOH extract of M. officinalis was dose-dependently inhibited to MMP-2 activity. The MeOH extract, hexane and EtOAc fractions $(IC_{50}\;of\;>200\;{\mu}g/mL)$ exhibited weak cytotoxicity activity, while butanol $(IC_{50}=80\;{\mu}g/mL)$ and chloroform fractions $(IC_{50}=90\;{\mu}g/mL)$ exhibited relatively strong cytotoxic activity. From these results, M. officinalis could be suitable for cancer treatment and chemopreventive drugs.