The phenolic acids from the plant of Salvia miltiorrhiza

Seven new phenolic acids, 7, 8-epiblechnic acid (1), 8-epiblechnic acid 9-ehthyl-9'-methyl ester (2), 9'-ehyl-isolithospermate (3), 9''-methyl-isolithospermate (4), 9'-ethyl-9''-methyl-isolithospermate (5), 9', 9''-dimethyl-isolithospermate (6), sebesteniod E (7), were isolated from the roots of Salvia miltiorrhiza. Their structures were elucidated by detailed spectroscopic means including UV, IR, HRESIMS, and NMR data spectra. The bioactive assays of compounds 1-7 against neuroprotection activities were determined. The results suggested that compound 4 exhibited a moderate glutamate-induced neuroprotective activity and the cell survival rate was 24.0% (10-5 mol/L), while compound 2 showed weak activity (survival rate: 7.58%, 10-5 mol/L), using PHPB (survival rate: 7.56%, 10-5 mol/L) as positive control.