Biochemical changes associated with the administration of aqueous pulp extract of Irvingia gabonensis fruit on adult male Wistar rats

Abstract

This study evaluates the medicinal and therapeutic importance of aqueous pulp extract of Irvingia gabonensis (APEIG) fruit on some biochemical indices in adult male albino rats. Thirty-six adult male rats were grouped into 3 groups of 12 rats each. Group 1 was the control, while groups 2 and 3 received 100 and 200 mg/kg body weight of the extract respectively. The quantitative and qualitative phytochemical constituents present in the APEIG were alkaloids, flavonoids, and terpenoids in moderate amounts, while saponins, tannins, glycosides, sterols, and phenols were detected in trace amounts. The treatment lasted for 21 days and biochemical parameters were analyzed following standard procedures. Results obtained indicated a reduction in the bodyweight of the treated groups. The serum cholesterol, LDL, and VLDL concentrations were significantly moderated in the treatment groups, although, the serum HDL concentration was elevated dose-dependently on days 14 and 21. Alkaline phosphatase (ALP) was elevated in the treatment groups on days 7 and 14 while aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, urea, uric acid, total protein, and albumin were not affected by the administration of (APEIG) on days 7, 14 and 21. Serum bilirubin was significantly lowered in the treatment groups on days 7, 14, and 21 while fasting blood glucose (FBS) of the treated groups was moderate. The results revealed that the administration of APEIG had promising medicinal potentials and could be harnessed in disease management. This study evaluates the medicinal and therapeutic importance of aqueous pulp extract of Irvingia gabonensis (APEIG) fruit on some biochemical indices in adult male albino rats. Thirty-six adult male rats were grouped into 3 groups of 12 rats each. Group 1 was the control, while groups 2 and 3 received 100 and 200 mg/kg body weight of the extract respectively. The quantitative and qualitative phytochemical constituents present in the APEIG were alkaloids, flavonoids, and terpenoids in moderate amounts, while saponins, tannins, glycosides, sterols, and phenols were detected in trace amounts. The treatment lasted for 21 days and biochemical parameters were analyzed following standard procedures. Results obtained indicated a reduction in the bodyweight of the treated groups. The serum cholesterol, LDL, and VLDL concentrations were significantly moderated in the treatment groups, although, the serum HDL concentration was elevated dose-dependently on days 14 and 21. Alkaline phosphatase (ALP) was elevated in the treatment groups on days 7 and 14 while aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, urea, uric acid, total protein, and albumin were not affected by the administration of (APEIG) on days 7, 14 and 21. Serum bilirubin was significantly lowered in the treatment groups on days 7, 14, and 21 while fasting blood glucose (FBS) of the treated groups was moderate. The results revealed that the administration of APEIG had promising medicinal potentials and could be harnessed in disease management. Plants and plant-based foods provide essential nutrients for the wellbeing and promotion of good health in humans and animals [[1]Anaduaka E.G. Uchendu N.O. Ezeanyika L.U.S. Mineral, amino acid and fatty acid evaluations of Myristica fragrans seeds extracts.Sci Afr. 2020; 10e00567https://doi.org/10.1016/j.sciaf.2020.e00567Crossref Scopus (6) Google Scholar]. A large population of the human race depends on some plant species for its basic diet of carbohydrates, fats, and proteins [[2]Egras A.M. Hamilton W.R. Lenz T.L. Monaghan M.S. An evidence-based review of fat modifying supplemental weight loss products.J Obes. 2011; 20: 29-36https://doi.org/10.1155/2011/297315Crossref Scopus (43) Google Scholar]. Although these plant species may constitute some medicinal and pharmacological potential [[3]Ekeyi Y. Uchendu N.O. Anaduaka E.G. Ezeanyika L.U.S. Ethanol extract of Cassia sieberiana leaves ameliorates deviances associated with benign prostatic hyperplasia in rats.All Life. 2021; 14: 473-483https://doi.org/10.1080/26895293.2021.1927857Crossref Scopus (2) Google Scholar], their abuse may be detrimental to the system if not monitored. Irvingia gabonensis belong to the species of African tree in the genus Irvingia of the Irvingiaceae plant family commonly known as wild mango, African mango, bush mango, or ugiri (Igbo) [[4]Omonkhua A.A. Onoagbe I.O. Effect of long-term oral administration of aqueous extract of Irvingia gabonensis bark on blood glucose and liver profile of normal rabbits.J Med Plant Res. 2012; 6: 2581-2589https://doi.org/10.5897/JMPR11.561Crossref Google Scholar,[5]Adeseko C.J. Sanni D.M. Salawu S.O. Kade I.J. Fatoki T.H. HPLC-UV Standard Phenolic Constituents of African Bush Mango (Irvingia gabonensis) and Molecular Docking on Polyphenol Oxidases.J Appl Life Sci Int. 2019; 22: 1-11https://doi.org/10.9734/JALSV2019/v221130119Crossref Google Scholar]. It has yellow fruits when ripe, and varies in size and shapes between varieties with fibrous pulp covering the seed [[6]Orwa C. Mutua A. Kindt R. Jamnadass R. Simons A. Agroforestree Database: a tree reference and selection guide version 4.0.http://www.worldagroforestry.org/af/treedb/Date: 2009Google Scholar]. Traditionally, the pulp of this fruit is eaten fresh and the seeds are used as a food additive, and as such possess superb economic and nutritional advantages [[7]Peter P.I. Victor M. The Effect of Irvingia gabonensis Ethanol Extracts (Ogbono) Seeds on the growth rate and hematological parameters in Wistar rats.J Biomed Sci. 2020; 9: 1-4https://doi.org/10.36648/2254-609X.9.2.3Crossref Google Scholar]. They are good sources of phytochemicals including the likes of alkaloids, flavonoids, saponins, tannins, and glycosides, as well as proteins, minerals, vitamins, carbohydrates, fats, and soluble fibres [[8]Asoiro F.U. Ezeoha S.L. Anyanwu C.N. Aneke N.N. Physical properties of Irvingia gabonensis, Detarium microcapum, Mucuna pruriens and Brachystegia eurycoma seeds.Heliyon. 2020; 6 (1-8)e04885https://doi.org/10.1016/j.heliyon.2020.e04885Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar]. Studies have shown that Irvingia gabonensis pulp extract possesses therapeutic potentials which are beneficial, including but not limited to weight loss [[3]Ekeyi Y. Uchendu N.O. Anaduaka E.G. Ezeanyika L.U.S. Ethanol extract of Cassia sieberiana leaves ameliorates deviances associated with benign prostatic hyperplasia in rats.All Life. 2021; 14: 473-483https://doi.org/10.1080/26895293.2021.1927857Crossref Scopus (2) Google Scholar] and antioxidant activity [[9]Agbor G.A. Oben J.E. Ngogang J.Y. Xinxing C. Vinson J.A. Antioxidant capacity of some herbs/spices from Cameroon: a comparative study of two methods.J Agric Food Chem. 2005; 53: 6819-6824https://doi.org/10.1021/jf050445cCrossref PubMed Scopus (79) Google Scholar]. Other traditional uses of the bark decoction are in treating scabies, toothache, skin diseases, diarrhoea, or dysentery, and due to its hypoglycaemic effect, serve as an anti-diabetic agent [[4]Omonkhua A.A. Onoagbe I.O. Effect of long-term oral administration of aqueous extract of Irvingia gabonensis bark on blood glucose and liver profile of normal rabbits.J Med Plant Res. 2012; 6: 2581-2589https://doi.org/10.5897/JMPR11.561Crossref Google Scholar,[10]Obianime A.W. Uche F.I. Effects of aqueous extracts of Irvingia gabonensis seeds on the hormonal parameters of male guinea pigs.Asian Pac J Trop Med. 2010; 3: 200-204Crossref Scopus (7) Google Scholar]. Thus, there is a great interest in determining the phytoconstituents and further, ascertain the effect of APEIG on some biochemical indices and possible therapeutic importance and probable safety and toxicity nature in adult male albino rats. The ripe fruits of Irvingia gabonensis were sourced from the University of Nigeria, Nsukka zoological garden. The fruit was identified and authenticated by a botanist of the International Centre for Ethno-medicine and Drug Development, Nsukka. Thirty-six adult male albino rats were sourced from the animal farm of the Faculty of Veterinary Medicine and housed in the animal house of the Department of Biochemistry in the same University. The animals were acclimatized for seven days with a 12-hour light/dark cycle maintained on a regular feed and water. The Faculty of Biological Science, University of Nigeria, Nsukka Committee on Research Ethics approved the protocols for this study before its commencement (UNN/FBS/EC/1026). The fruits of Irvingia gabonensis were collected, the epicarps were peeled off, and the mesocarps were separated from the endocarp with the aid of a knife. The mesocarp was blended with a blending machine (Sonic, China). A known quantity, 100 g of blended fruits of Irvingia gabonensis were macerated in 20 ml of distilled water with thorough shaking at room temperature. The resulting solution was filtered using a Whatman No. 1 filter paper. A fresh filtrate of 100 g/20 ml was obtained daily and used for the study throughout the experiment. The qualitative and quantitative phytochemical determination of the fruit extract of Irvingia gabonensis adopted the methods described by [[11]Harborne J.B. Phytochemical methods: a guide to modern techniques of plant analysis. Chapman and Hall Ltd, London1973: 279Google Scholar,[12]Trease G.E. Evans W.C. Pharmacognosy.15th Ed. Saunder Publishers, London2002: 42-44Google Scholar]. Thirty-six (36) adult male albino rats weighing 180–220g were used in this study. They were randomly grouped into three groups of 12 rats each. The rats were orally fed graded doses of extract of Irvingia gabonensis. Group 1 was the control, while groups 2 and 3 consumed 100 and 200 mg/kg body weight of the extract respectively for 21 days. Blood samples of the rats were collected on days zero (0), seven (7), fourteen (14), and twenty-one (21) through ocular puncture for biochemical analysis. The blood samples were collected in plain tubes and then centrifuged at 2000 rpm after which the serum was separated and kept in the refrigerator for 3 weeks at a temperature of 8oC for biochemical analysis at the end of the experiment. The serum ALP, AST, and ALT were determined by the methods of [[13]Reitman S. Frankel A.S. A colorimetric method of determination of serum glutamic oxaloacetic and glutamic pyruvic transaminases.Am J Clin Pathol. 1957; 28: 53-63https://doi.org/10.1093/ajcp/28.1.56Crossref Scopus (7432) Google Scholar]. Lipid profile tests were carried out using standard diagnostic kits as described by [[14]Allain C.C. Poon L.S. Chan C.S. Richmond W. Fu P.C. Enzymatic determination of total serum cholesterol.Clin Chem. 1974; 20: 470-475Crossref PubMed Scopus (7158) Google Scholar]. The serum urea and uric acid levels were determined by the methods of [[15]Orsonneau J.L. Massoubre C. Cabanes M. Lustenberger P. Simple and sensitive determination of urea in serum and urine.Clin Chem. 1992; 38: 619-623Crossref PubMed Scopus (35) Google Scholar,[16]Kabasakalian P. Kalliney S. Westcott A. Determination of Uric Acid in Serum, with use of Uricase and a Tribromophenol-Aminoantipyrine Chromogen.Clinical Chemistry. 1973; 19: 522-524https://doi.org/10.1093/clinchem/19.5.522Crossref PubMed Scopus (89) Google Scholar] respectively. The serum total protein was determined using the method of [[17]Doumas B.T. Watson W.A. Biggs H.G. Albumin standards and the measurement of serum albumin with Bromocresol green.Clinica Chemica Acta. 1971; 31: 87-96https://doi.org/10.1016/0009-8981(71)90365-2Crossref PubMed Scopus (2648) Google Scholar]. The serum albumin was determined using the method of [[18]Doumas B. Peters Jr., T. Serum and urine albumin: a progress report on their measurement and clinical significance.Clinica Chimica Acta. 1997; 258: 3-20https://doi.org/10.1016/s0009-8981(96)06446-7Crossref PubMed Google Scholar]. Creatinine was determined by the method described by [[19]Moore J.F. Sharer J.D. Methods for Quantitative Creatinine Determination.Curr Protoc Hum Genet. 2017; 93: 1-7https://doi.org/10.1002/cphg.38Crossref PubMed Scopus (18) Google Scholar]. The total bilirubin was determined by the method described by [[20]Westwood A. The analysis of bilirubin in serum.Ann Clin Biochem. 1991; 28: 119-130https://doi.org/10.1177/000456329102800202Crossref PubMed Scopus (51) Google Scholar] using a test kit. The fasting blood sugar (FBS) levels were determined following the method described by [[21]Uchendu N.O. Nkwocha C.C. Anaduaka E.G. Ezeanyika L.U.S. Metabolic syndrome in adult male rats induced by feeding beef tallow-enriched homemade diet with fructose-containing drinking water.Comp Clin Path. 2021; 30: 541-547https://doi.org/10.1007/s00580-021-03248-7Crossref Scopus (1) Google Scholar]. The qualitative and quantitative phytochemical constituent of the aqueous fruit extract of Irvingia gabonensis is presented in Table 1. The result revealed the presence of alkaloids, flavonoids, saponins, tannins, glycosides, terpenoids, sterols, and phenols in the extract, while anthraquinones and anthocyanins were absent. Flavonoids and tannins were more abundant.Table 1Qualitative and quantitative phytochemical constituent of aqueous fruit extract of Irvingia gabonensis.PhytochemicalsInferenceConcentrationAlkaloids++2.26 ± 0.08 (mg/100g)Flavonoids+++6.60 ± 0.01 (mg/100g)Saponins+0.90 ± 0.01 (mg/100g)Tannins+++6.33 ± 0.02 (mg/100g)Glycosides+0.40 ± 0.03 (mg/100g)Terpenoids++4.68 ± 0.02 (mg/100g)Steroids+0.52 ± 0.01 (mg/100g)Phenols+1.23 ± 0.02 (μg/100g)Anthraquinones−Anthocyanins−− Absent; + present; ++ moderate; +++ High. Values are means ± SD, n = 3. Open table in a new tab − Absent; + present; ++ moderate; +++ High. Values are means ± SD, n = 3. There was a significant (p < 0.05) reduction in urea and creatinine concentrations in groups 2 and 3 on days 7 and 21 compared to the control while uric acid level significantly (p < 0.05) lowered on day 14 in the treated groups compared to the control (Table 2).Table 2Effects of aqueous pulp extract of Irvingia gabonensis on renal indices of adult male albino rats.ParametersGroupsDays071421Urea (mg/dl)123.00 ± 4.58a25.33 ± 4.04a28.33 ± 5.77a47.00 ± 9.60a225.33 ± 3.51a17.67 ± 4.73b16.30 ± 2.52b32.67 ± 1.53b320.33 ± 7.57a16.67 ± 1.53b35.33 ± 4.73a30.00 ± 3.61bUric acid (mg/dl)16.47 ± 0.70a5.37 ± 1.83a8.20 ± 0.56b8.33 ± 1.04a26.53 ± 0.91a6.60 ± 0.26b7.30 ± 0.36a7.47 ± 0.63a35.97 ± 1.35a8.17 ± 1.46b7.23 ± 0.12a7.46 ± 0.44aCreatinine (mg/dl)10.83 ± 0.15a0.90 ± 0.10a1.03 ± 0.15a,c1.67 ± 0.32a20.90 ± 0.10a0.67 ± 0.12b0.83 ± 0.06a1.17 ± 0.06b30.77 ± 0.21a0.60 ± 0.10b1.20 ± 0.17c1.03 ± 0.15bValues are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05.Group one: Normal control.Group two: Received 100 mg/kg of APEIG.Group three: Received 200 mg/kg of APEIG. Open table in a new tab Values are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05. Group one: Normal control. Group two: Received 100 mg/kg of APEIG. Group three: Received 200 mg/kg of APEIG. There was no significant (p > 0.05) reduction in the treated groups on days 9, 12, 15, and 18 compared to the control (Fig. 1). There were no significant (p > 0.05) variations in the total cholesterol, TAG, LDL, and VLDL in the treated groups across the days. However, HDL was significantly high in group 3 compared to groups 1 and 2 (Table 3).Table 3Effects of aqueous pulp extract of Irvingia gabonensis on serum lipid profile of adult male albino rats.ParametersGroupsDays071421Total Cholesterol (mmol/l)14.00 ± 0.20a3.50 ± 0.17a4.33 ± 0.45a4.60 ± 0.35a23.77 ± 0.59a3.80 ± 0.10a3.77 ± 0.45a4.60 ± 0.26a33.73 ± 0.25a3.60 ± 0.26a4.57 ± 0.49a4.50 ± 0.26aTAG (mmol/l)11.27 ± 0.46a1.93 ± 0.23a1.27 ± 0.51a2.27 ± 0.25a21.43 ± 0.23a1.63 ± 0.58a1.20 ± 0.44a1.87 ± 0.32a30.93 ± 0.15a1.90 ± 0.36a0.93 ± 0.41a2.00 ± 0.26aHDL (mmol/l)11.57 ± 0.15a1.50 ± 0.00a1.97 ± 0.21b,c1.57 ± 0.21b21.60 ± 0.10a1.53 ± 0.12a1.77 ± 0.15b1.57 ± 0.21b31.40 ± 0.20a1.43 ± 0.06a2.10 ± 0.10c2.00 ± 0.10cLDL (mmol/l)12.20 ± 0.10a1.57 ± 0.12a2.10 ± 0.70a2.60 ± 0.53a21.80 ± 0.40a1.87 ± 0.21a1.77 ± 0.15a2.63 ± 0.21a32.10 ± 0.26a1.73 ± 0.15a2.10 ± 0.10a2.06 ± 0.23aVLDL (mmol/l)10.23 ± 0.06a0.43 ± 0.06a0.27 ± 0.06a0.43 ± 0.06a20.37 ± 0.21a0.40 ± 0.00a0.23 ± 0.06a0.40 ± 0.10a30.23 ± 0.05a0.43 ± 0.06a0.20 ± 0.10a0.43 ± 0.06aValues are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05.Group one: Normal control.Group two: Received 100 mg/kg of APEIG.Group three: Received 200 mg/kg of APEIG. Open table in a new tab Values are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05. Group one: Normal control. Group two: Received 100 mg/kg of APEIG. Group three: Received 200 mg/kg of APEIG. There was a significant (p < 0.05) decline in ALP activity on day 7 of the treated groups compared to the control. AST had no significant changes on days 7 and 21 of treated groups compared to the control. Furthermore, ALT and total bilirubin were not significantly lowered in the treated groups compared to the control. Total protein and albumin were significantly (p < 0.05) lowered on days 14 and 21 respectively in group 3 compared to the control (Table 4).Table 4Effects of aqueous pulp extract of Irvingia gabonensis on serum liver markers of adult male albino rats.ParametersGroups0Days71421ALP (U/L)131.67 ± 1.53a37.33 ± 2.31a35.00 ± 1.73a36.67 ± 7.02a226.67 ± 8.62a27.00 ± 2.00b30.33 ± 5.69a26.33 ± 4.93a,b326.00 ± 1.00a25.33 ± 2.52b32.00 ± 3.00a22.67 ± 4.16bAST (U/L)159.33 ± 7.64a,c65.67 ± 0.58a48.67 ± 6.43a,b62.33 ± 3.22a247.33 ± 2.31b63.33 ± 17.47a54.67 ± 13.79b61.67 ± 4.51a357.67 ± 1.53c54.33 ± 11.24a36.00 ± 4.58c65.33 ± 3.51aALT (U/L)116.33 ± 1.16a20.67 ± 4.04a18.33 ± 5.69a20.00 ± 4.36a216.00 ± 1.73a18.67 ± 3.06a15.67 ± 0.58a18.00 ± 2.65a317.00 ± 2.65a20.00 ± 2.65a18.00 ± 2.65a18.67 ± 5.51aTotal Protein (g/dl)16.83 ± 0.92a7.53 ± 0.38a7.23 ± 1.17a7.57 ±1.17a25.00 ± 0.26b7.50 ± 1.18a6.40 ± 1.15a,c7.60 ± 0.95a35.30 ± 1.25b,a6.53 ± 0.76a4.97 ± 0.87c7.93 ± 1.45aAlbumin (g/l)12.40 ± 0.27a4.03 ± 1.07a3.33 ± 0.15a3.40 ± 0.17a22.17 ± 0.21a3.77 ± 0.15a3.30 ±0.17a3.57 ± 0.06a32.13 ± 0.31a3.17 ± 0.55a3.33 ± 0.50a3.77 ± 0.12aTotal Bilirubin (mg/dl)10.87±0.12a0.74 ± 0.16a0.91 ± 0.05a0.90 ± 0.06a20.88±0.06a0.77 ± 0.04a0.73 ± 0.07a0.72 ± 0.07a30.90±0.03a0.63 ± 0.10a0.79 ± 0.04a0.76 ± 0.12aValues are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05.Group one: Normal control.Group two: Received 100 mg/kg of APEIG.Group three: Received 200 mg/kg of APEIG. Open table in a new tab Values are means ± SD, n = 3. Values with a different superscript in the same column are significantly different at p < 0.05. Group one: Normal control. Group two: Received 100 mg/kg of APEIG. Group three: Received 200 mg/kg of APEIG. Plant secondary metabolites play significant roles in combating oxidative stress-related diseases because of their antioxidant potentials [[22]De Bruyne T. Pieters L. Deelstra H. Vlietinck A. Condensed vegetables tannins: biodiversity in structure and biological activities.Biochem Syst Ecol. 1999; 27: 445-459https://doi.org/10.1016/S0305-1978(98)00101-XCrossref Scopus (180) Google Scholar]. In the study, the presence of the phytochemical constituents in the extract has been reported in other studies [[21]Uchendu N.O. Nkwocha C.C. Anaduaka E.G. Ezeanyika L.U.S. Metabolic syndrome in adult male rats induced by feeding beef tallow-enriched homemade diet with fructose-containing drinking water.Comp Clin Path. 2021; 30: 541-547https://doi.org/10.1007/s00580-021-03248-7Crossref Scopus (1) Google Scholar,[22]De Bruyne T. Pieters L. Deelstra H. Vlietinck A. Condensed vegetables tannins: biodiversity in structure and biological activities.Biochem Syst Ecol. 1999; 27: 445-459https://doi.org/10.1016/S0305-1978(98)00101-XCrossref Scopus (180) Google Scholar]. Flavonoids, which have been shown to have strong antioxidant properties, inhibit oxidative stress, and quenching free radicals in the system [[23]Etebu E. Differences in fruit size, Postharvest Pathology and Phytochemicals between Irvingia gabonensis and Irvingia wombolu.Sustain Agric Res. 2012; 2: 52-61https://doi.org/10.5539/sar.v2n1p52Crossref Google Scholar]. Glycosides are beneficial in managing congestive heart failure [[24]Mahomoodally M.F. Traditional medicines in Africa: an appraisal of ten potent African medicinal plants.Evid Based Complement Alternat Med. 2013; (Article ID 617459): 1-14https://doi.org/10.1155/2013/617459Crossref Scopus (215) Google Scholar]. Terpenoids that were documented in this study agree with the report from [[25]Onyechi A.U. Ibeanu V.N. Eme P. Eze K. Madubike K. Nutrient, Phytochemical composition and consumption pattern of soursop (Annona muricata) pulp and drink among workers in University of Nigeria, Nsukka community.Pak J Nutr. 2015; 14: 866-870https://doi.org/10.3923/pjn.2015.866.870Crossref Scopus (1) Google Scholar]. Terpenoids possess therapeutic effects such as antimicrobial properties, anti-carcinogenic, anti-malarial, anti-ulcer, septicidal, antimicrobial, or diuretic activity [[26]Wolfe O.A. Ijeoma U.F. Effects of aqueous extracts of Irvingia gabonensis seeds on the hormonal parameters of male guinea pigs.Asian Pac J Trop Med. 2010; 3: 200-204https://doi.org/10.1016/S1995-7645(10)60009-0Crossref Scopus (8) Google Scholar,[27]Ajayi O.B. Akomolafe S.F. Adefioye A. Proximate Analysis, Mineral Contents, Amino Acid Composition, Anti-Nutrients and Phytochemical Screening of Brachystegia Eurycoma Harms and Pipper Guineense Schum and Thonn.Am J Food Nutr. 2014; 2: 11-17https://doi.org/10.12691/ajfn-2-1-3Crossref Google Scholar]. In herbal medicine, tannin-containing plant extracts are used in diarrhoea, stomach upset, and anti-inflammatory management [[28]Chung K.T. Wong T.Y. Wei C.I. Huang Y.W. Lin Y. Tannins and human health: a review.Crit Rev Food Sci Nutr. 1998; 38: 421-462https://doi.org/10.1080/10408699891274273Crossref PubMed Scopus (1168) Google Scholar]. While saponins play a strong antibiotics role and prevent microbial growth [[29]Anaduaka E.G. Ogugua V.N. Egba S. Apeh V.O. Investigation of some important phytochemical, nutritional properties and toxicological potentials of ethanol extracts of Newbouldia laevis leaf and stem.Afr J Biotechnol. 2013; 12: 5846-5854https://doi.org/10.5897/AJB2013.12308Crossref Google Scholar]. The significant increase in serum uric acid levels may be attributed to the presence of tannins. Tannins have been linked to the decreases in feed intake/efficiency, and protein digestibility in monogastric animals [[28]Chung K.T. Wong T.Y. Wei C.I. Huang Y.W. Lin Y. Tannins and human health: a review.Crit Rev Food Sci Nutr. 1998; 38: 421-462https://doi.org/10.1080/10408699891274273Crossref PubMed Scopus (1168) Google Scholar]. Although the impact of tannins on animals depends on the type of animals and their physiological state, feed, the amount and type of tannins in the diets [[30]Huang Q. Liu X. Zhao G. Hu T. Wang Y. Potential and challenges of tannins as an alternative to in-feed antibiotics for farm animal production.Animal Nutrition. 2018; 4: 137-150Crossref PubMed Scopus (158) Google Scholar]. It has been reported that the addition of tannins in pig diets (0.0125%–0.1%) adversely affected growth rate and haematology indices in pigs [[31]Lee S.H. Shinde P.L. Choi J.Y. Kwon I.K. Lee J.K. Pak S.I. Effects of tannic acid supplementation on growth performance, blood hematology, iron status and faecal microflora in weanling pigs.Livest Sci. 2010; 131: 281-286Crossref Scopus (47) Google Scholar]. In this study, a quantifiable number of tannins were present in APEIG as shown in the phytochemical constituent's result. The effects of tannins on serum uric acid levels and other biochemical parameters have been documented [[32]Barszcz M. Taciak M. Tuśnio A. Skomial J. Effects of dietary level of tannic acid and protein on internal organ weights and biochemical blood parameters of rats.PLoS ONE. 2018; 13e0190769https://doi.org/10.1371/journal.pone.0190769Crossref PubMed Scopus (13) Google Scholar]. The significant decrease in serum urea level observed in rats administered 100 mg/kg and 200 mg/kg body weight of the APEIG in this study (Table 2) may be associated with the presence of essential amino acids in the aqueous fruit extract of the Irvingia gabonensis. Amino acid profiles of Irvingia species have been documented [[33]Oduntan A.O. Babalola S.O. Kenneth-Obosi O. Awe O.F.E. Olabode I.A. Egbekunle K. et al.Evaluation of proximate, amino acid profile and oil characterisation of Irvingia wombolu fruit pulp and peel.International Food Research Journal. 2019; 26: 1371-1377Google Scholar]. It has been suggested that dietary amino acid compositions play a critical role in the regulation of urea synthesis [[34]Tujioka K. Ohsumi M. Hayase K. Yokogoshi H. Effect of the quality of dietary amino acids composition on the urea synthesis in rats.J Nutr Sci Vitaminol. 2011; 57: 48-55https://doi.org/10.3177/jnsv.57.48Crossref PubMed Scopus (5) Google Scholar]. The significant reduction in the serum creatinine levels in this study after the administration of APEIG suggests that the extract had no negative effect on the kidney. This is because an increase in creatinine is observed when the kidney is damaged or malfunctions [[35]Dixon T. Seeba Z. Abdelgadir E.E.E. Ahmed L.O.H. Limitations of serum creatinine as a marker of renal function.Sch Acad J Pharm. 2017; 6: 168-170https://doi.org/10.21276/sajpCrossref Google Scholar]. In this study, fasting blood sugar was reduced in the groups treated with APEIG (Fig. 1). This suggests that APEIG may be effective in reducing the fasting blood sugar level in normoglycaemic rats and hence useful in managing diabetes mellitus through the elevation of insulin concentration and thereby stimulating the pancreatic beta-cell functionality [[36]Ngondi J.L. Djiotsa E.J. Fossouo Z. Oben J. Hypoglycaemic effect of the methanol extract of Irvingia gabonensis seeds on streptozotocin diabetic rats.Afr J Tradit Complement Altern Med. 2006; 3: 74-77Crossref Scopus (9) Google Scholar]. The lipid profile result (Table 3) showed a moderate attenuating effect on the serum total cholesterol, LDL, VLDL levels, and subsequently a significant increase in serum HDL in the male albino rats. The potential effects of the extract on the lipid profile may be associated with the decline in the synthesis of cholesterol and its metabolism, as well as the expression of signal receptors of LDL [[37]Anaduaka E.G. Egba S.I. Ugwu J.U. Apeh V.O. Ugwu O.P.C. Effects of dietary tyrosine on serum cholesterol fractions in rats.Afr J Biochem Res. 2014; 8: 95-100Crossref Google Scholar]. LDL plays a major role in the development of atherosclerosis, especially after their oxidation while HDL reverses cholesterol transport and transfer of cholesterol esters from cell membranes which free cholesterol to the core of the HDL and inhibits the oxidation of LDL [[2]Egras A.M. Hamilton W.R. Lenz T.L. Monaghan M.S. An evidence-based review of fat modifying supplemental weight loss products.J Obes. 2011; 20: 29-36https://doi.org/10.1155/2011/297315Crossref Scopus (43) Google Scholar,[21]Uchendu N.O. Nkwocha C.C. Anaduaka E.G. Ezeanyika L.U.S. Metabolic syndrome in adult male rats induced by feeding beef tallow-enriched homemade diet with fructose-containing drinking water.Comp Clin Path. 2021; 30: 541-547https://doi.org/10.1007/s00580-021-03248-7Crossref Scopus (1) Google Scholar]. The decrease in the serum ALP activity (Table 4) indicates the possible absence of adverse effects of APEIG intake on the pathologies of the bone and liver since elevated serum ALP activity has been associated with bone diseases. Also, the significant reduction in serum ALP activity by APEIG may perhaps indicate the absence of cholestasis (lack of bile flow). Alkaline phosphatase (ALP) is an important indicator of liver function test, whose elevation is universally recognized as a marker of hepatobiliary or skeletal diseases [[38]An L. Yin W. Sun D. Albumin-to-alkaline phosphatase ratio as a promising indicator of prognosis in human cancers: is it possible?.BMC Cancer. 2021; 21: 1-18https://doi.org/10.1186/s12885-021-07921-6Crossref PubMed Scopus (3) Google Scholar,[39]Eteng M.U. Ibekwe H.A. Abolaji A.O. Okoi A.I. Onwuka F.C. Osuchukwu N.C. Effect of Rauwolfia vomitoria (Apocynaceae) extract on serum amino transferase and alkaline phosphatase activities and selected indices of liver and kidney functions.Afr J Biotechnol. 2009; 8: 4604-4607https://doi.org/10.5897/AJB2009.000-9422Crossref Google Scholar]. The non-significant decrease and increase observed in the level of AST may be an indication of the absence of liver damage, which may be associated with APEIG administration. The concentration of ALT in serum decreased after the administration of APEIG suggests that our extract was not toxic to the liver. The non-significant increase in ALT levels may be attributed to the presence of the natural toxicant tannins and saponins in the fruit extract, which may affect the bioavailability of mineral elements in the diet [[29]Anaduaka E.G. Ogugua V.N. Egba S. Apeh V.O. Investigation of some important phytochemical, nutritional properties and toxicological potentials of ethanol extracts of Newbouldia laevis leaf and stem.Afr J Biotechnol. 2013; 12: 5846-5854https://doi.org/10.5897/AJB2013.12308Crossref Google Scholar]. The protein concentration of the experimental rats at the end of the experiment was not significantly elevated compared to the concentration at the beginning of the experiment. This may indicate that the serum total proteins increased with age and support the report by [[40]Pandya D. Nagrajappa A.K. Ravi K.S. Assessment and correlation of urea and creatinine levels in saliva and serum of patients with chronic kidney disease, diabetes and hypertension– A research study.J Clin Diagn Res. 2016; 10: 58-62https://doi.org/10.7860/JCDR/2016/20294.8651Crossref Scopus (57) Google Scholar]. The aqueous extract did not have any effect on the albumin and total bilirubin level of male albino rats. This study suggests that the administration of APEIG stabilizes and attenuates several biochemical parameters, including fasting blood sugar, lipid profile, liver, and kidney indices. These emphasize its usefulness in preventing and managing medical conditions that could arise from the aforementioned parameters.