Antioxidant activity, total phenolics, and rosmarinic acid content in different basils (Ocimum spp.)

Basil (Ocimum spp.) has been used for many years in foods as a flavoring agent, in perfumery, and in medicine. The antioxidant capacity as Trolox equivalent antioxidant capacity (TEAC) and total phenolic contents, based on Folin-Ciocalteu reagent, in different Ocimum species were quantitated. High-performance liquid chromatography (HPLC) was used to identify and quantify rosmarinic acid, the predominant nonvolatile polyphenol in each Ocimum species. Among seven Ocimum spp. there was a wide range of antioxidant activity. A high linear correlation between total antioxidant capacity and phenolic content was observed (r(2) = 0.8822), and a positive relationship also existed between antioxidant activity and rosmarinic acid (r(2) = 0.8393). Antioxidant capacity was associated with the plants' phenolic components and with rosmarinic acid. Our results demonstrated that those species rich in phenolic constituents demonstrated high antioxidant activity, and that rosmarinic acid is a major contributor to this activity in the species and chemotypes evaluated. Basil is an important source of naturally occurring antioxidants, and elite species could be incorporated in breeding programs.