Health attributes of ethnic vegetables consumed in the Eastern Anatolia region of Turkey: Antioxidant and enzyme-inhibitory properties

Background: Four ethnic vegetables from the Eastern Anatolia region of Turkey, Malva neglecta Wallr., Plantago lanceolata L., Cichorium intybus L. and Eryngium bornmuelleri Nab. are commonly used by the local population for food preparation. This study aimed at understanding their potential health attributes. Methods: Hydrophilic extracts obtained from roots, stems, leaves and flowers were evaluated for their antioxidant capacities [total phenolics (TP), ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) assays] and suppression of two isolated key enzymes relevant to metabolic syndrome: α-glucosidase and pancreatic lipase. Phytochemical composition of extracts was investigated by high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS). Results: The evaluated extracts exhibited pronounced antioxidant capacities, comparable to those of common spices and herbs, and effectively suppressed the activities of isolated α-glucosidase and pancreatic lipase enzymes. These activities correlated well with total phenolics contents. Plantago lanceolata was an effective inhibitor of α-glucosidase and C. intybus of pancreatic lipase enzyme. High performance liquid chromatography mass spectrometry analyses revealed the dominance of luteolin glycosides in P. lanceolata. The same compound was present in C. intybus, where it was accompanied by significant amounts of cichoric, chlorogenic and caftaric acid. Malva neglecta and E. bornmuelleri contained the lowest levels of phenolic compounds and exhibited the lowest antioxidant and enzyme inhibitory activities. Conclusions: Among the investigated ethnic vegetables, P. lanceolata and C. intybus represent a valuable source of antioxidant phytochemicals of phenolic nature that modulated in vitro the activities of digestive enzymes. These ethnic food sources diversify diet and enhance health attributes of foods.