Plant and Growth Condition Interactions on the Phenolic Compound Contents and Antioxidant Activity in Salvia circinata Cav., a Medicinal Sage

Abstract

The genus Salvia has a worldwide distribution, and its contribution to traditional medicine and as an aromatic plant has been recognized since ancient times, with few documented species having a similar phytochemical composition. In this study, the effects of natural growth conditions (in situ) and ex situ cultivation and sampling locations on the phenolic compound contents and antioxidant activity of methanolic extracts of Salvia circinata from Oaxaca, Mexico, were investigated. Stem and young leaf samples were collected from plants growing in situ in two locations in Oaxaca and later from plants propagated clonally or vegetatively from propagules obtained in situ but grown ex situ. In both sets of samples, the contents of total polyphenols and flavonoids and the antioxidant activity were evaluated by spectrophotometry, and subsequently, the contents of phenols and specific flavonoids were identified and quantified by high-performance liquid chromatography with diode-array detection (HPLC–DAD). The growth conditions and locality of origin of the samples significantly influenced the contents of total polyphenols and flavonoids and antioxidant activity, with the in situ conditions in the locality of Reforma, Oaxaca, favoring higher levels. Two phenolic acids (chlorogenic and rosmarinic) and two flavonoids (isoquercitrin and rutin) were identified, and the concentrations of these compounds were influenced by the growth conditions and localities of origin of the samples.