GUARANA SEED EXTRACT: GOOD SOURCE OF BIOACTIVE COMPOUNDS
Gordana Ćetković, Vesna Tumbas, Mojca Skerget, Jasna Ćanadanović-Brunet, Sonja Djilas
and Zeljko Knez
Chemistry of Natural Products, Faculty of Technology Novi Sad, University of Novi Sad, Serbia
Abstract:
Guarana (Paullinia cupana, Sapindaceae) is a Brazilian native plant, with seeds being the only part suitable for human
consumption. The seeds are rich in caffeine, containing up to 8% of the drug, along with small amount of other xanthine
alkaloids (theophylline and theobromine) and diferent compounds such as polyphenols, saponins, starch, fats, choline
and pigments. The main polyphenols in guarana seeds are catechins. The aim of this study was to investigate the
composition of guarana seed extract, obtained by extraction with 60% ethanol, as well as its antioxidant activity against
reactive hydroxyl and stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The contents of polyphenols (172.2 mg
gallic acid/g) and proanthocyanidins (49.3 mg/g) were determined spectrophotometrically, while the contents of caffeine
(128.4 mg/g) and catechins, such as epicatechin (31.13 mg/g) and epicatechin gallate (3.75 mg/g), were analysed by
HPLC. The antioxidative activity was measured by electron spin resonance (ESR) spectroscopy. Antioxidant activities
of guarana seed extract on hydroxyl and DPPH radicals, expressed as EC50 values, were 0.275 mg/ml and 0.036 mg/ml,
respectively. Our results suggest that seed extracts of guarana possess strong antioxidant activity, and they can therefore
be used as a natural additive in food, cosmetic and pharmaceutical industries.
