In vitro anti-diabetic properties of different organs of two Juncaceae species

Abstract

This work reports the in vitro anti-diabetic potential and the antioxidant activity of extracts made from roots, aerial parts and seeds of two Juncaceae species common in southern Portugal, namely Juncus acutus and Juncus maritimus. Methanol and dichloromethane extracts were prepared and evaluated for their in vitro inhibitory activity against enzymes implicated on the onset of type II diabetes (T2DM), namely α-amylase and α-glucosidase. The antioxidant activity was also determined through the study of the radical scavenging activity (RSA) of the extracts on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and nitric oxide (NO) radicals. The methanol extract of J. maritimus seeds and the dichloromethane extract of J. acutus roots had the highest RSA against DPPH (IC50= 0.17 mg/mL and 0.18 mg/mL, respectively). Dichloromethane extracts of J. acutus roots had the highest RSA against ABTS (IC50= 0.22 mg/mL). In the α-glucosidase inhibitory assay, methanol extracts from the three organs of J. acutus displayed IC50 values less than 0.2 mg/mL, significantly lower than the positive control, acarbose (IC50= 3.1 mg/mL). Additionally, seeds from J. maritimus had α-amilase inhibitory potential (IC50= 7.8 mg/mL), similar to acarbose (IC50= 7.8 mg/mL). Our findings suggest that J. acutus and J. maritimus can be sources of antioxidant compounds and of molecules suitable for reducing the postprandial blood glucose level in T2DM.