Synergistic postprandial blood glucose modulatory properties of Vernonia amygdalina (Del.), Gongronema latifolium (Benth.) and Occimum gratissimum (Linn.) aqueous decoctions

• Published in: Journal of ethnopharmacology Vol. 149; no. 1; pp. 111 - 116
• Main Authors: Ejike, Chukwunonso E.C.C., Awazie, Samuel O., Nwangozi, Precious A., Godwin, Chima D.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 26.08.2013
• Subjects: analysis; animal models; Apocynaceae; Apocynaceae - chemistry; blood glucose; Blood Glucose - analysis; chemistry; Drug Synergism; Ethnopharmacology; Female; glucose tolerance; Glucose Tolerance Test; Gongronema latifolium (Benth.); green leafy vegetables; Humans; Hypoglycemic Agents; Hypoglycemic Agents - isolation & purification; Hypoglycemic Agents - pharmacology; isolation & purification; Male; Medicine, African Traditional; Nigeria; Occimum gratissimum (Linn.); Ocimum; Ocimum - chemistry; OGTT; pharmacology; plant extracts; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Leaves; Plant Leaves - chemistry; Postprandial blood glucose; Postprandial Period; recipes; synergism; Vernonia; Vernonia - chemistry; Vernonia amygdalina; Vernonia amygdalina (Del.); Nigeria; Gongronema latifolium (Benth.); Occimum gratissimum (Linn.); OGTT; Vernonia amygdalina (Del.); Postprandial blood glucose
• ISSN: 0378-8741; 1872-7573; 1872-7573
• DOI: 10.1016/j.jep.2013.06.009

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. Twenty seven subjects were recruited and (on separate days) were given 150mL of water, VA, GL and OG decoctions or blends of the decoctions to drink 45min before a 2-h OGTT. Their OGTT curves were plotted and areas under the curves (AUCs) calculated. 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%). 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. [Display omitted]