Preliminary study on the material basis of anti-melanoma activity of Veronica didyma

Abstract

To clarify the anti-melanoma active extract and material basis of Veronica didyma, CCK8 method was used to evaluate the inhibitory effects of four extracts (petroleum ether extract, ethyl acetate extract, n-butanol extract, water extract), ethanol extracts and monomer compounds on the proliferation of melanoma cell lines (B16 and A375). The chemical constituents of the active fraction were systematically separated and purified by phytochemical techniques and methods. The results were as follows: (1) Ethyl acetate extract (PPNE) had a better inhibitory effect on the proliferation of B16 and A375 cells than other samples, and IC50 = 0.177 mg·mL-1 (B16), IC50 = 2.826 mg·mL-1 (A375), respectively. (2) Seven monomer compounds were obtained from PPNE were p-hydroxybenzaldehyde (1), picroside II (2), isoscutellarein 7-O-(6′″-oacetyl)-β-allopyranosyl (1′″→2″)-β-glucopyranoside (3), 3′-hydroxyl-4′-O-methylisoscutellarein 7-O-［6′″-O-acetyl-β-D-allopyranosyl-(1→2)-β-D-glucopyranoside (4), 6-O-veratroylcatalposide (5), veronicoside (6), isoscutellarein 4′-methyl ether 7-O-(6′″-O-acetyl)-ballopyranosyl (1′″→2″)-β-glucopyranoside (7). (3) Seven compounds were isolated from this plant for the first time, and HPLC showed that these seven compounds were the major components of PPNE. (4) Except Compound 1, the other six monomers all had good inhibitory effects on the proliferation of melanoma cells, and the anti-melanoma activities of compounds 3, 4 and 7 were reported for the first time. Based on these results, PPNE of V. didyma is an anti-melanoma active fraction, iridoids (compounds 2, 5, 6) and flavonoids (compounds 3, 4, 7) may be the basis of anti-melanoma activity of PPNE. The results of this study will lay scientific foundation for the rational utilization of V. didyma’s resources.

Keywords

• veronica didyma tenore
• chemical composition
• melanoma
• separation and purification
• bioassay-guided