An analytical and theoretical approach for the profiling of the antioxidant activity of essential oils: the case of Rosmarinus officinalis L.

The antioxidant constituents of essential oils (EOs) of Rosmarinus officinalis L. (\u3b1-pinene chemotype) were isolated at the flowering (A), post-flowering (B), and vegetative stages (C). GC-MS was used to analyze total chemical composition, Folin-Ciocalteau and Prussian blue methods for reducing substances. Radical scavenging capacity (DPPH test, IC(50) 36.78\ub10.38, 79.69\ub11.54, 111.94\ub12.56\u3bcL) and anti-lipoperoxidant activity (TBARS, IC(50) 0.42\ub10.04, 1.20\ub10.06\u3bcL, 4.07\ub10.05\u3bcL) differed widely in the three stages. Antioxidant activity, identified after silica gel fractionation chromatography, was closely related (R(2)=0.9959) to each EO's content of hydroxilated derivatives, (containing alcohols, phenols and 1,8 cineole): 15.26\ub10.12%, 7.22\ub10.06%, and 5.09\ub10.10% in EOs from A, B, and C. Modeling the C, H, O terpenes in a simulated phospholipid bilayer indicated that anti-lipoperoxidant activity depended on the stability and rapidity of their interactions with the membrane bilayer components, and their positioning over its surface