GA 2018

Diabetes is a chronic disease with growing prevalence worldwide. In addition to conventional therapy, many patients use phytotherapeutic preparations for the management of diabetes. The goal of this study was to assess the phytochemical composition and biological activity of species most used for phytotherapy of diabetes in Croatia: areal parts of yarrow (Achillea millefolium), wormwood (Artemisia absinthium) and common centaury (Centaurium erythraea), elderflower (Sambucus nigra), white mulberry (Morus alba) and sage (Salvia officinalis) leaf, as well as hulls of beans (Phaseolus vulgaris). The TXRF analysis has shown that the plant samples did not contain elevated amounts of heavy metals. In addition to that, chromium, the metal important for combating insulin resistance, was found in the wormwood sample. Aqueous and ethanolic (80 %) extracts were prepared from the selected plants, and the chemical composition and biological activity of the extracts compared. Polyphenolic content was higher in the ethanolic than in the aqueous extracts. Rutin and chlorogenic acid were the most abundant phenols in the extracts. The richest in total phenols, flavonoids and phenolic acids was ethanolic mulbery leaf extract (154.51±22.64 mg QE/g). The extracts have shown excellent antiradical activity, as well as the ability to inhibit beta-carotene degradation in presence of linoleic acid, with some being as active as the positive control, BHA. Chelating activity, on the other hand, was significantly weaker. alpha-glucosidase-inhibiting activity of the investigated extracts was excellent. The most remarkable example were the mulbery leaf extract, as well as yarrow extract. Their activity did not differ from the activity of acarbose. The presented results may explain the extent and popularity of the selected medicinal plants use as a supportive therapy of diabetes in Croatia.