Biological activity and phytochemical analysis of extracts obtained from Santolina rosmarinifolia L.

Species from Asteracea family have long been used in traditional medicine being described as important sources of bioactive compounds. Within this family, Santolina spp. have been used due to evidenced medicinal properties. This genus is widely distributed in the Mediterranean area and there has been a renewed interest in screening plants from this genus for novel biologically active compounds in order to unveil future industrial applications. Santolina rosmarinifolia L, a perennial shrub with lime-yellow aromatic foliage, presents multiple medicinal properties. To address the potential of S. rosmarinifolia as a source of bioactive products, the phytochemical profile and biological activity of hydroethanolic and of aqueous (decoction and infusion) extracts was made. Phytochemical evaluation was performed though spectrophotometric methods (total phenolics, flavonoids, ortho-diphenols, tannins, hydroxycinnamic acids, flavones and flavonols). Antioxidant capacity was evaluated by determining DPPH and ABTS radical-scavenging activities, hydroxyl and nitric oxide radicals, and superoxide and hydrogen peroxide scavenging activity. Cytotoxicity against HepG2 and RAW264.7 cells was assessed, using alamar-blue assay. Results showed that phytochemical composition varied in aqueous extracts with infusion showing higher percentage of flavonoids and ortho-diphenols while decoction showed a lower amount of hydroxycinnamic acids. Regarding radical scavenging activities, aqueous extracts exhibited lower DPPH and ABTS radical-scavenging activity compared to hydroethanolic extract. Both cell lines were susceptible to tested extracts at 24 and 48h. However, lower concentrations were required to induce higher cytotoxic effects in prolonged extract exposure (48h). In general, hydroethanolic extracts showed lower IC₅₀ compared to aqueous extracts (at 24 and 48h exposure). Results presented here contribute to value this plant species as a possible source of bioactive phytochemicals with prospective physiological benefits, concerning to antioxidant and anti-proliferative activities.

INTERACT-project-NORTE-01 – 0145-FEDER-000017 (ISAC), co-financed by ERDF through NORTE-2020. And grants (BI/UTAD/INTERACT/ISAC/203/2016, to L.F.), (PD/BD/52563/2014, to M.T.).