title: Synergistic postprandial blood glucose modulatory properties of Vernonia amygdalina (Del.), Gongronema latifolium (Benth.) and Occimum gratissimum (Linn.) aqueous decoctions.
abstract: BACKGROUND
  Traditional healers in Nigeria use a combination of decoctions from green leafy vegetables in their blood glucose (BG) lowering recipes. Three plants Vernonia amygdalina (Del.) (VA), Gongronema latifolium (Benth.) (GL) and Occimum gratissimum (Linn.) (OG) are found consistently in such recipes. Whereas the anti-diabetic properties of extracts of these plants have been reported in animal models, little is known about the effects of their aqueous decoctions (singly or in combinations) on oral glucose tolerance (OGT) in humans.
  
  
  METHODS
  Twenty seven subjects were recruited and (on separate days) were given 150 mL of water, VA, GL and OG decoctions or blends of the decoctions to drink 45 min before a 2-h OGTT. Their OGTT curves were plotted and areas under the curves (AUCs) calculated.
  
  
  RESULTS
  The results show that each of the three decoctions neither altered the peak time of the OGTT nor significantly (P>0.05) reduced the BG concentrations (BGCs) at any time point on the test curves relative to the baseline. VA, OG and GL gave 0.4, 0.2 and 2.8% reductions in the AUCs, respectively, relative to the baseline. Blending GL and VA did not improve the results. However, a decoction containing the three vegetables in equal proportions significantly reduced the BGCs at 90 (96.8 ± 9.5 vs. 107.1 ± 10.2mg/dL; P=0.041) and 120 (92.8 ± 14.3 vs. 102.5 ± 12.1mg/dL; P=0.037) minutes relative to the baseline, and gave better reductions in the AUCs (4.1%).
  
  
  CONCLUSIONS
  The decoction containing the three vegetables was found to be superior in activity to any 1, or blends of only 2, of the 3 decoctions. This is a case of positive synergism, and justifies the use of these plants in ethnopharmacological BG lowering recipes.
authors.affiliation: Michael Okpara University of Agriculture, Umudike, Department of Biochemistry, PMB 7267 Umuahia, Abia State, Nigeria. nonsoejikeecc@yahoo.com
authors.forename: Chukwunonso E C C
authors.initials: CE
authors.lastname: Ejike
authors.forename: Samuel O
authors.initials: SO
authors.lastname: Awazie
authors.forename: Precious A
authors.initials: PA
authors.lastname: Nwangozi
authors.forename: Chima D
authors.initials: CD
authors.lastname: Godwin
mesh_terms: D029062:Apocynaceae / Q000737:chemistry*; D001786:Blood Glucose / Q000032:analysis*; D004357:Drug Synergism; D020834:Ethnopharmacology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007004:Hypoglycemic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D016488:Medicine, African Traditional; D009549:Nigeria; D031339:Ocimum / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D019518:Postprandial Period; D035741:Vernonia / Q000737:chemistry*
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010936:Plant Extracts
keywords: Gongronema latifolium (Benth.); OGTT; Occimum gratissimum (Linn.); Postprandial blood glucose; Vernonia amygdalina (Del.)