engleski

Phytochemical screening and antioxidant potential of eight members from the genus Galium L.

Species from the genus Galium L. have long been used in folk medicine as diuretics, choleretics, adstringents, sedatives, in the treatment of gout, kidney stones and gallstones, diarrhea, skin disorders and wounds, bone fractures and epilepsy, with Galium verum L. being one of the most commonly used. Aerial parts of eight Galium taxa (Galium corrudifolium Vill., G. cruciata (L.) Scop., G. divaricatum Pourret ex Lam., G. lucidum All., G. mollugo L., G. palustre L., G. parisiense L. and G. verum L.) were harvested from the Šibenik area in Croatia during their flowering season in 2012. Phytochemical screening of the taxa was done on dry powdered plant material as well as on 80%-methanolic extracts prepared by ultrasound-assisted extraction. Contents of total phenolics and flavonoids were determined spectrophotometrically by using the Folin-Ciocalteu's reagent and aluminium chloride, respectively, while iridoid content was evaluated by using the Trim-Hill reagent. Evaluation of antioxidant potential was based on two in vitro assays, the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and the 2, 2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. All investigated species gave positive reactions for flavonoids and iridoids, while most of them contained saponins, steroids, triterpenes and tannins. Total phenolic content, which ranged from 61.5 to 111.0 mg gallic acid equivalents/g dry extract, was highest for G. cruciata, while G. verum contained the highest amount of flavonoids (23.1 mg quercetin equivalents/g dry extract) and iridoids (461.3 mg aucubin equivalents/g dry extract). Both antioxidant activity assays indicated that G. cruciata (IC50 = 27.6-30.3 μg/mL) and G. divaricatum (IC50 = 30.3-34.7 μg/mL) together with G. verum (IC50 = 30.7-36.7 μg/mL) have the greatest antioxidant potential. The results of this study support the known healing properties of G. verum, but also suggest several related species, namely G. cruciata, G. divaricatum and G. palustre, as candidates for further research.

Galium; total phenolics; flavonoids; iridoids; antioxidant potential

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