Abietane diterpenoids with anti-oxidative damage activity from Rosmarinus officinalis.

Nine new and nineteen known compounds were isolated and identified from Rosmarinus officinalis under the guidance of bioassay and LCMS. They were all belonged to abietane diterpenoids which enriched the types of compounds in Rosmarinus officinalis especially the discovery of a series of 20-norabietane diterpenoids (4, 6-9 and 26-27). The anti-oxidative damage activity of the compounds was tested on H2O2 damaged SH-SY5Y cells. Compounds 5, 6 and 7 presented moderate ability for promoting the growth of damaged cells. Compounds 10, 11, 13-20 27 and 28 displayed high anti-oxidative damage effect whose cell viability rates were more than 80%. The anti-oxidative damage effect of 11, 16, 18 and 20 were higher than that of EGCG (positive control) in which 11, 18 and 20 were the acetylated derivatives of carnosic acid (10), 7alpha-methoxy-isocarnosol (16) and carnosol (19) respectively. It suggested that 10-carboxyl/formyl of abietane diterpenoids was essential for maintaining the anti-oxidative damage activity and the adjacent hydroxyl groups on benzene ring were less important for holding the bioactivity. These acetylated derivatives with high bioactivity and stability could be regarded as new sources of antioxidants or anti-oxidative damage agents being used in food and medical industry.