Phenolic profile and antioxidant properties of dried buckwheat leaf and flower extracts

Aleksandra Misan, Bojana Saric, Ivan Milovanovic, Pavle Jovanov, Ivana Sedej, Vanja Tadic, Anamarija Mandic, Marijana Sakac
2017 Chemical Industry and Chemical Engineering Quarterly  
Article Highlights • Buckwheat leaf and flower extracts were obtained by different extraction procedures • Rutin and chlorogenic acid were identified as most abundant phenolic compounds • Some of the extracts were as efficient as BHT in β-carotene bleaching test • The extracts demonstrated strong ability to inhibit the destruction of erythrocytes • The extracts prolonged the beginning of the oxidation process in sunflower oil Abstract Due to a high content of rutin (2-10%), dried buckwheat leaf
more » ... ried buckwheat leaf and flower (DBLF) formulations were shown to be efficient in the treatment of vascular diseases. In order to find a cost effective way for the extraction of antioxidants, the effects of ethanol/water ratio and temperature on the extraction efficiency of phenolic compounds and the mechanisms of antioxidant action of the extracts were tested. Extraction with ethanol/water mixture (80:20, v/v) for 24 h at room temperature, after the mixture was just brought to boil was demonstrated to be an efficient and cheap way for obtaining a high yield of rutin (49.94±0.623 mg/g DBLF). The most abundant phenolic compounds in DBLF extracts were rutin and chlorogenic acid. Flavonoids, especially rutin, were shown to be the most responsible for the antioxidant activity in all investigated lipid model systems, acting as free radical scavengers, electron-donating substances and chelators of iron ions. In β-carotene bleaching tests, the extracts with the highest activity were as efficient as BHT (butylated hydroxytoluole). Regarding the results of antihemolytic and Schaal oven tests, the extracts demonstrated remarkable ability to inhibit the oxidative destruction of erythrocytes and to prolong the beginning of the oxidation process in sunflower oil. Keywords: dried buckwheat leaf and flower, rutin, antioxidant activity, lipid oxidation, extraction. Common buckwheat (Fagopyrum esculentum Moench) is a highly nutritious pseudocereal known as a very rich source of antioxidants, especially rutin [1]. The nutritive profile and antioxidant potential of buckwheat seeds has been extensively investigated [2] [3] [4] , and buckwheat seeds can now be regarded a "functional food" [5] . However, recent studies indicate that the highest concentration of rutin, up to 10%, is accu-
doi:10.2298/ciceq150704004m fatcat:2f6taz5odzeozpfzfyi4uy4gy4