Phenolic compounds from the aerial parts of malva verticillata and their anti-diabetic effect

The EtOAc, n-BuOH, and aqueous fractions from the aerial parts of Malva verticillata have been shown to promote significant recovery from alloxan-induced pancreatic islet (PI) damage in zebrafish larvae at 10 μg/mL. Therefore, this study aimed to identify the principal active components of these plant parts and their pharmacological properties. Repeated SiO₂ and octadecyl SiO₂ column chromatography with the aerial parts of M. Verticillata led to isolation of four phenolic compounds; these compounds were identified as benzyl-α-D-galactopyranoside (1), (-)-secoisolariciresinol-9'-O-β-D-glucopyranoside (2), transferulic acid (3), and trans-ferulic acid methyl ester (4) on the basis of physicochemical and spectroscopic analyses including infrared, nuclear magnetic resonance, and fast atom bombardment-mass spectroscopy. Compounds 1-4 were first isolated from M. Verticillata in this study. Furthermore, compounds 1-4 recovered alloxan-induced PI damage in zebrafish. Especially, compound 3 recovered the size of the injured PIs by 83.8% (p=0.0007) compared to the alloxaninduced group, while compound 4 by 33.4% (p=0.0072). It is the first report that trans-ferulic acid (3) exhibited the protective effect on zebrafish larvae PIs damaged by alloxan.