A new triterpene saponin and known compounds from the polar extract of Salvia argentea L. and evaluation of their antioxidant activity

Abstract

A new triterpene saponin, 2, 3, 21, 23-tetrahydroxyolean-12-en-28-oic-acid-28-O-β-D- glucosyl-(2’’→1’)-β-D-glucoside (1), was isolated from the n-butanol extract of dried aerial parts of Salvia argentea L. (Lamiaceae) in addition to two known flavonoids, apigenin 7-O-β-D-glucoside (2), threo-guaiacylglycerol 3-O-[6-O-p-hydroxybenzoyl]-β-D-glucoside (3), luteolin 7-O-β-D-glucoside (4), verbascoside (5) and rosmarinic acid (6). The structure elucidation of these compounds was based on analyses of spectroscopic data including 1D-, 2D-NMR and HR-ESI-MS techniques and by comparing their NMR data with those reported in the literature. Compound 6 exhibited the highest antioxidant activity in DPPH assay (IC₅₀<3.00 µg/mL) which was better than the standards BHA, BHT, Trolox and ascorbic acid.

Graphical Abstract

Keywords:

• Salvia argentea L
• lamiaceae
• triterpene saponin
• flavonoids
• polyphenols
• rosmarinic acid
• antioxidant activity

Acknowledgements

The authors are grateful to DGRSDT-MESRS (Algeria), to CNRS, Conseil Regional de Champagne-Ardenne, Conseil General de la Marne, Ministry of Higher Education and Research (MESR, France) and to CRBt- Constantine, Algeria.

Supplementary material

HR-ESI–MS, UV,¹H NMR,¹³C NMR, COSY and HMBC spectra of compound 1 and antioxidant activity tests are found in the Supplementary material.

Disclosure statement

The authors declare no conflict of interests.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.