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. (α-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, IC50 36.78 ± 0.38, 79.69 ± 1.54, 111.94 ± 2.56 μL) and anti-lipoperoxidant activity (TBARS, IC50 0.42 ± 0.04, 1.20 ± 0.06 μL, 4.07 ± 0.05 μL) differed widely in the three stages. Antioxidant activity, identified after silica gel fractionation chromatography, was closely related (R2 = 0.9959) to each EO's content of hydroxilated derivatives, (containing alcohols, phenols and 1,8 cineole): 15.26 ± 0.12%, 7.22 ± 0.06%, and 5.09 ± 0.10% 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.