Antioxidant capacity and polyphenolic composition as quality indicators for aqueous infusions of Salvia officinalis L. (sage tea)

Stephan Walch

doi:10.3389/fphar.2011.00079

Abstract

Sage (Salvia officinalis L.) is used as an herbal medicinal product, with the most typical form of application as infusion with boiling water (sage tea). The well-established traditional uses include symptomatic treatment of mild dyspeptic complaints, the treatment of inflammations in the mouth and the throat, and relief of excessive sweating and relief of minor skin inflammations. In this study, sage teas prepared from commercially available products were chemically analyzed for polyphenolic content using liquid chromatography, for antioxidant potential using the oxygen radical absorbance capacity method, and for the Folin–Ciocalteu (FC) index. The sage teas showed a high variation for all parameters studied (up to 20-fold differences for rosmarinic acid). Univariate and multivariate analyses showed that the antioxidant potential, which varied between 0.4 and 1.8 mmol trolox equivalents/100 mL, was highly dependent on rosmarinic acid and its derivatives. The FC index also showed a high correlation to these polyphenols, and could therefore be used as a screening parameter for sage tea quality. The considerable differences in polyphenolic composition and antioxidant capacity between the brands lead to a demand for quality standardization, especially if these sage teas are to be used for therapeutic purposes. Further research also appears to be necessary to characterize the dose–benefit relationship, as sage may also contain a constituent (thujone) with potentially adverse effects.

Highlights

Sage (Salvia officinalis L.) has been an important herbal medicinal product since very early times and is still in wide use today
We have focused on the beneficial effects of sage due to antioxidant capacity and polyphenol content, as analyzed by a recently developed methodology (Zimmermann et al, 2011)
For full results including validation data and measurement uncertainty, see Zimmermann et al (2011). bThe concentration refers to the aqueous tea infusion ready for consumption as prepared according to the labeling. cMeasured as luteolin-glucuronide. dMeasured as rosmarinic acid. eMeasured as carnosic acid

Summary

Introduction

Sage (Salvia officinalis L.) has been an important herbal medicinal product since very early times and is still in wide use today. Wellestablished traditional uses of sage include symptomatic treatment of mild dyspeptic complaints, the treatment of inflammations in the mouth and the throat, and relief of excessive sweating and minor skin inflammations, only a few clinical trials far have been conducted to corroborate these uses. The efficacy of sage for the treatment of hot flushes during menopause was proven by a multicentre open clinical trial (Bommer et al, 2009). Sage combined with Echinacea was efficacious in the treatment of acute sore throats (Schapowal et al, 2009). A double-blind, randomized, and placebo-controlled trial indicated that sage may improve the symptoms of Alzheimer’s disease (Akhondzadeh et al, 2003). Sage tea was effective in the improvement of lipid profile, antioxidant defenses, and lymphocyte Hsp protein expression in human volunteers (Sá et al, 2009)

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Conclusion