Evaluation of the Immunomodulatory Activity of Gnetum africanum (Gnatacae) Leaf Extracts



  • Ngozi U. Madubogwu Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences,  Chukwuemeka Odumegwu Ojukwu University Igbariam, Anambra State, Nigeria
  • Prince C. Unekwe Department Pharmacology and Therapeutics, Faculty of Basic Clinical Sciences, Nnamdi Azikiwe University Awka, Anambra State, Nigeria
  • Earnest O. Erhirhie Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences,  Chukwuemeka Odumegwu Ojukwu University Igbariam, Anambra State, Nigeria
  • Ifeoma B. Chukwurah Department of Pharmacology and Therapeutics, Faculty of Basic Clinical Sciences, Chukwuemeka Odumegwu Ojukwu University Igbariam, Anambra State, Nigeria
  • Daniel L. Ajaghaku Department Pharmacology, Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, Enugu state. Nigeria
  • Festus B.C. Okoye Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria


Lipid peroxidation, Irish potato, Avocado pear, Pawpaw, Plantain, Gastric ulcer


Antioxidants of plant origin reduce or inhibit oxidative stress-induced tissue damage in gastric ulcers. Plants’ edible and non-edible parts have been investigated as potential sources of natural antioxidants. The present study aims at investigating the antioxidant potentials of aqueous extracts of Irish potato tubers, Avocado pear seeds, and unripe pawpaw and plantain fruits used traditionally in ulcer treatment. In vitro anti-oxidative potential of the plants was assessed using their inhibitory effects on H2O2-induced lipid peroxidation, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals generation. The plants’ phenolic profile and total antioxidant capacity (TCA) were assessed using gas chromatography equipped with flame ionization detector and phosphomolybdenum method respectively. Total phenolic compounds content ranged from 598.80 µg/g in Irish potato through 171.44 µg/g and 123.11 µg/g in avocado pear and pawpaw respectively to 77.14 µg/g in the plantain. Irish potato (149 ± 13.02 mg AAE/g) and avocado pear (146.60 ± 4.53 mg AAE/g) had significantly (p<0.05) higher TCA than pawpaw (53.31 ± 7.16 mg AAE/g) and plantain (35.55 ± 3.13 mg AAE/g). Generally, Irish potato and avocado pear had the lowest values of 50% inhibitory concentrations (IC50) against OH free radicals and lipid peroxidation, while Irish potato and pawpaw had the lowest IC50 valuesagainst DPPH radical. Irish  potato and avocado pear were observed to have highest phenolic compounds distribution and TCA values, which translated to their higher in vitro antioxidant potency. The observed rich TCA and phenolic contents, and high radical scavenging abilities showed that the plants possess potent antioxidant properties. 


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How to Cite

U. Madubogwu, N., C. Unekwe, P., O. Erhirhie, E., B. Chukwurah, I., L. Ajaghaku, D., & B.C. Okoye, F. (2021). Evaluation of the Immunomodulatory Activity of Gnetum africanum (Gnatacae) Leaf Extracts: doi.org/10.26538/tjnpr/v5i11.25. Tropical Journal of Natural Product Research (TJNPR), 5(11), 2043–2050. Retrieved from https://tjnpr.org/index.php/home/article/view/359

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