Antioxidant and enzyme-inhibitory activity of extracts from Erigeron annuus flower

Abstract

Erigeron annuus (L.) Pers. has been used in folk medicine for the treatment of several diseases. To develop and apply it, we report (for the first time) the antioxidant, enzyme-inhibitory activities, and toxicity of various solvent extracts from Erigeron annuus flower (EAF). The EAF was extracted using seven solvents (water, methanol, ethanol, acetone, ethyl acetate, chloroform, and hexane) to obtain extracts, respectively. The chemical composition of extracts was also determined by spectrophotometric methods (total phenolic content (TPC), total flavonoid content (TFC), total carbohydrate content (TCC), ultraviolet and infrared spectroscopy, high-performance liquid chromatography coupled with electrospray ionization mass spectrometry, and nuclear magnetic resonance spectroscopy. The aqueous extract had the highest TPC and TCC. The methanol extract showed the highest TFC. Pyromeconic acid (PY) was the major component of EAF, which was present in all extracts and was prepared by sublimation. The ethanol extract exhibited the highest content of PY (1.4 %). The methanol extract showed the strongest ability to scavenge 2,2-diphenyl-1-picrylhydrazyl radicals. Acetone extract and PY against 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt cation radicals, and hydroxyl radicals. The methanol extract exhibited the highest antioxidant activity in ferric-reducing antioxidant power, and cupric ion-reducing antioxidant capacity assays. The best chelating activity of ferrous ions was shown in the chloroform extract. Methanol and acetone extracts proffered the highest protection against cellular oxidative damage. Hexane and chloroform extracts had the highest inhibitory activity towards α-glucosidase and α-amylase, respectively. The hexane extract and PY showed high toxicity against HeLa cells. Taken together, these results suggest possible novel applications of EAF as a source of innovative bioactive ingredients for human nutrition and/or phytomedicine.