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 14 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 alloxan-induced 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.