Identification and characterization of polyphenols and volatile terpenoid compounds in different extracts of garden sage (Salvia officinalis L.)

Abstract

Introduction: Garden sage (Salvia officinalis L.) is an important medicinal and aromatic herb, used in various food, pharmaceuticals and cosmetic industries for its potential antioxidant properties. Leaves are the source of essential oils and polyphenols, used as a raw material in food and pharmaceutical industries. Materials and Methods: The study aimed to develop a complete phytochemical profile of S. officinalis leaves through liquid chromatography coupled with quadrupole‑time of flight mass spectrometry (UHPLC‑ESI‑QTOF‑MS) and gas chromatography with a flame ionization detector (GC‑FID). Soxhlet and sonicated extract were analyzed using UHPLC, data‑independent acquisition in negative electrospray ionization mode. Essential oil profiling of leaves in comparison with leaves+ stem was carried out using GC‑FID. Results: Among the extraction methods, Soxhlet extraction yielded significantly high levels of caffeic acid (92.45 ± 1.92 µg/g), rosmarinic acid (18821.33 ± 150.20 µg/g), luteolin‑7‑glucoside (635.13 ± 11.20 µg/g), carnosic acid (27.48 ± 2.37 µg/g), carnosol (1347.67 ± 30.04 µg/g), and ursolic acid (14938.67 ± 82.20 µg/g). Among the 43 identified phenolic compounds, two flavonoids, diosmetin and pectolinarigenin and two triterpenoids benthamic and micromeric acids have been first time detected in S. officinalis leaves. The results of essential oil analysis indicated the presence of α‑thujone (34.43‑ 38.93 %), β‑thujone (6.03‑7.58 %), camphor (15.77‑18.12 %), 1,8‑cineole (5.45‑6.21 %), α‑humulene (5.20 %), and camphene (4.29‑5.10 %) as major volatile terpenoid components in S. officinalis. Conclusion: Soxhlet extraction found to be the best method for polyphenol extraction and the essential oil extracted only from leaves best suitable for therapeutic purposes due to less α‑thujone and β‑thujone content.