Inhibitory effect of leaf extract of <i>Newbouldia laevis</i> on the metabolic activities of alpha-glucosidase and alpha-amylase

Abstract

In this study, the effect of ethanol extract of the leaves of Newbouldia laevis on the activity of α-amylase and α-glucosidase was investigated. Inhibitory effect of N. laevis extract on α-glucosidase was tested in vitro using baker's yeast α-glucosidase and rat intestinal α-glucosidase while α-amylase inhibitory effect was assayed using rat pancreatic α-amylase. α-Glucosidase inhibitory effect of the extract was also tested in vivo in diabetic and non-diabetic rats. N. laevis extract exhibited good α-glucosidase inhibitory activity in vitro with IC50 values of 2.2 µg/mL and 43.5 µg/mL for baker's yeast and rat intestinal α-glucosidase respectively. The extract also inhibited rat pancreatic α-amylase activity with IC50 value of 58.7 µg/mL. In both diabetic and non-diabetic rats, N. laevis extract caused a significant reduction in postprandial blood glucose level after oral sucrose load. The results of this study indicate that N. laevis extract exerts its glucose-lowering effect through inhibition of α-glucosidase and α-amylase. Article Info

Screening of metabolites from endophytic fungi of some Nigerian medicinal plants for antimicrobial activities

“…Newbouldia laevis (Bignoniaceae), Ocimum gratissimum (Lamiaceae), and Carica papaya (Caricaceae) are medicinal plants commonly found in Nigeria. These plants have been used ethnomedicinally in the treatment of several disease conditions including ulcers, burns, diarrhea, bleeding, haemorrhoids, dysentery, abdominal pains, cough, colds, pruritus, stress, headache, pneumonia, conjunctivitis, diabetes mellitus, epilepsy and convulsions (4)(5)(6)(7)(8)(9)(10)(11)(12).…”

“…Various scientific studies have shown that N. Laevis possesses antimicrobial, antidiabetic, antioxidant, and antimalarial activities (11)(12)(13)(14). O. gratissimum has been reported to show antidiabetic, antioxidant, anxiolytic, sedative, anti-inflammatory, hepatoprotective, antitumor, gastroprotective, hypolipidemic, insecticidal, nematicidal, and antibacterial activities (4,5,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27).…”

Antihyperglycemic Studies on the Leaf Extract and Active Fractions of &lt;i&gt;Newbouldia laevis&lt;/i&gt; (Bignoniaceae)

“…There is documented evidence that polyphenols slow down glucose absorption by competitive inhibition of the intestinal brush border membrane sodium-glucose co-transporter (SGLT 1) [80] as well as inhibition of disacharidases [81]. Kolawole and Abanji (2013) [82] reported the inhibition of alpha glucosidase and alpha amylase enzymes by the ethanolic leaf extract of N. laevis on sucrose fed rats. Phenolic compounds are known to directly cause regeneration of alloxan damaged islet beta cells by their action as antioxidants and free radical scavengers causing restoration of pancreatic beta cell function [83].…”

Synthesis, characterization and evaluation of antidiabetic activity of novel indoline derivatives

“…Alpha-amylase inhibitory activities of ascidians (Prabhu and Ananthan, 2014), Gossypium arboreum (Kazeem et al, 2013), Newbouldia laevis (Kolawole and Akanji, 2013) and Lantana camara (Swamy and Sinniah, 2015) were reported.…”