The structure of rosmariquinone — A new antioxidant isolated fromRosmarinus officinalis L.

Abstract A new diterpene, named rosmariquinone, was isolated from the leaves ofRosmarinus officinalis L. The leaves were first extracted using methanol and, upon further purification, this extract yielded rosmariquinone. Structure elucidation of the antioxidant was done using IR, MS,1H‐NMR and13C‐NMR.