The inhibitory activity of peonidin purple sweet potato in human epidermal receptor-2 receptor (her-2) expression by in silico study

An acetylated anthocyanin (peonidin) is one of the flavonoid group compounds contained in purple sweet potato (Ipomoea batatas) which has anticancer activity. Overexpression of Human Epidermal Receptor-2 receptor (HER-2) could induce spontaneous dimerization and autophosphorylation, and trigger the occurrence of focal adhesion kinase (FAK) activation in order to induce migratory process and breast cancer cell metastasis. Lapatinib is one the drug which used to inhibit over-expression of HER-2. The purpose of this study was to determined the inhibition mechanism of over-expression HER-2 protein of peonidin by using in silico molecular docking method. In silico method such as molecular docking is done through stages such as validation of molecular docking method, optimization of peonidin 3D structure, docking of peonidin with HER-2 protein which refers to the binding energy parameter where the lower binding energy value indicates the stronger and stable bond between peonidin with HER-2 protein. The binding energy of peonidin was compared with native ligand's binding energy and lapatinib's binding energy. The result of this study was peonidin's binding energy with HER-2 protein was -7,54 kcal/mol, while the native ligand's binding energy and lapatinib's binding energy with HER-2 protein were -5,77 kcal/mol and -0,56 kcal/mol. The binding energy indicates peonidin as a purified anthocyanin of purple sweet potato had potential activity as anti-breast cancer because it suppressed the excessive expression of the HER-2 protein.