Phenolic composition and antioxidant activity of Salvia tomentosa Miller: effects of cultivation, harvesting year, and storage

Salvia tomentosa is a common medicinal plant, and it is consumed as an herbal tea in some Mediterranean countries. It has been extensively collected from its natural habitat, and careless collection has caused the recent extinction of some plants. The present study was undertaken to cultivate S. tomentosa and compare the phenolic composition and antioxidant properties of wild and cultivated plants. Total phenolics, total flavonoids, and antioxidant activity of S. tomentosa ranged between 49.27 and 66.15 mg GAE g(-1) dry weight (dw), 36.27 and 40.83 mg catechin g(-1) dw, and 1.77 and 2.29 mg dw mg(-1) DPPH, respectively. Total phenolic content of the cultivated samples was higher than that of wild samples. Seventeen different phenolic compounds, comprising 7 phenolic acids and 10 flavonoids, were identified and quantified in S. tomentosa. As with the many Salvia species, rosmarinic acid was quantified as the main component of S. tomentosa. It was followed by caffeic acid, morin, p-coumaric acid, and myricetin. Chlorogenic acid, p-coumaric acid, morin, kaempferol, hesperetin, and apigenin were increased through cultivation; gallic acid, caffeic acid, ferulic acid, rutin, catechin, and epicatechin were decreased. During the 6-month storage only caffeic acid changed significantly.