**12. Some selected medicinal plants with antidiabetic potentials in Nigeria**

In Nigeria, two plants, *Mangifera indica and Vernonia amygdalina* have been ranked highest for their antidiabetic property. Diabetes mellitus is known to affect 3% on average of adult Nigerians [61] and the prevalence in northern Nigerian is put at 1.6% [62]. Some of the selected medicinal plants with antidiabetic potentials in Nigeria are listed below.

*Mangifera indica, Angeissus leiocarpus, Fiscus thonnigii, Khaya senegalensis,. Euphorbia convuludi‐ odes, Acacia nilotica, Vernonia amygdalina,Cassia goratensis,Cassia arereh, Calotropis procera, Senna occidentalis, Alluvium cepa, Ipomoea batatas, Vitex gekowskii,Ctrus medica, Parkta filicoidea, Allium sativum, Anacardium occidentalis, Azadirachata indica,Vitillarta paradoxa, Gossypium hirsutum,* *Lawsonia inermis, Moringa oleifera, Psidium guajava, Bauhinia reticulate, Balanites aegyptiaca, Lannea kerstingii, Daucus carota, Zizyphus spina, Anana senegalensis, Eugenia caryophyllata, Blighia sapida.*

groups of phytochemicals are the alkaloids, terpenes, and phenolics. Plant constituents such as polysaccharides, peptides, alkaloids, glycopeptides, triterpenoids, amino acids, steroids, xanthone, flavonoids, lipids, phenolics, coumarins, iridoids, alkyl disulphides, inorganic ions and guanidines are reported to have antidiabetic activities [49, 59]. More interestingly, the following phytochemicals are reported to have antidiabetic activity, aminoacids like hypo‐ glycin A and hypoglycin B, alkaloids like catharanthine, leurosine, lochnerine, arecoline and vindoline, pinitol, epicatechin, S-methyl cysteine sulphoxide, S-allyl cysteine sulphoxide, andrographolide, allicin (thio-2-propene-1- sulfinic acid S-allyl ester), shamimin, beta vul‐ garosides I–IV, glycoside of leucopelargonidin and leucodelphinidin, mangiferin, marsupsin, pterosupin, pterostilbene, salacinol, swerchirin, trigonelline, berberine, harmane, norharmane, pinoline, quercetin, chlorogenic acid, hesperidin, naringin, epigallocatechin gallate, charantin, galactonmannan, lactucain C, kaempferol glucosides, caffeoyl glucoside, bakuchiol, swerchir‐ in, thysanolactone, bellidifolin and kolaviron have been documented for potential phytonu‐

**11. Plant phytochemicals associated with insulinomimetic activity**

Vinca rosea (Apocynaceae), Zingiber officinale (Zingiberaceae).

medicinal plants with antidiabetic potentials in Nigeria are listed below.

They stimulate Beta cell rejuvenation, regeneration and stimulation increase insulin level, Irneccerepatoser insulin secretion and reduction of insulin binding on the insulin [34]. Some of the plant phytochemicals associated with insulinomimetic activity include the following: Abies pindrow Pinaceae, Acacia arabica (Leguminosae), Agrimony eupatoria (Rosaceae), Aloe barbadensis (Liliaceae), Annona squamosa (Annonaceae), Averrhoa bilimbi (Oxalidaceae), Bixa orellana (Bixaceae), Boerhaavia diffusa (Nyctaginaceae), Camellia sinensis (Theaceae), Capsicum frutescens (Solanaceae), Cinnamomum zeylanicum (Lauraceae), Clausena anisata (Rutaceae), Eucalyptus globulus (Myrtaceae), Ficus religiosa (Moraceae), Hibiscus rosa (Malvaceae), Helicteres isora (Sterculiaceae), Ipomoea batata (Convolvulaceae) Juniperus communis (Pinaceae), Olea europia (Oleaceae), Swertia chirayata (Gentianaeae), Scoparia dulcis (Scrophulariaceae),Tinospora crispa (Menispermaceae) Urtifca dioica (Urticaceae),

**12. Some selected medicinal plants with antidiabetic potentials in Nigeria**

In Nigeria, two plants, *Mangifera indica and Vernonia amygdalina* have been ranked highest for their antidiabetic property. Diabetes mellitus is known to affect 3% on average of adult Nigerians [61] and the prevalence in northern Nigerian is put at 1.6% [62]. Some of the selected

*Mangifera indica, Angeissus leiocarpus, Fiscus thonnigii, Khaya senegalensis,. Euphorbia convuludi‐ odes, Acacia nilotica, Vernonia amygdalina,Cassia goratensis,Cassia arereh, Calotropis procera, Senna occidentalis, Alluvium cepa, Ipomoea batatas, Vitex gekowskii,Ctrus medica, Parkta filicoidea, Allium sativum, Anacardium occidentalis, Azadirachata indica,Vitillarta paradoxa, Gossypium hirsutum,*

trients [60].

104 Antioxidant-Antidiabetic Agents and Human Health

The leaves of *Mangifera indica* are used as an antidiabetic agent in Nigerian folk medicine. The hypoglycemic activity of *Mangifera indica* has been reported in both rats and mice [63-64]. Aqueous extract of the leaves of *Mangifera indica* were found to possess hypoglycaemic activity against glucose-induced hyperglycaemia but not with normoglycaemic or STZ-induced diabetic rats and mice respectively [63-64]. The hypoglyceamic effect of this plant was thought to be by reduction of intestinal absorption of glucose. Antihyperglycaemic activity of aqueous stem bark extract of *Mangifera indica* was also reported by Ojewole [65]. The extract from the stem bark of *Mangifera indica* administered intraperitoneally in streptozotocin induced diabetics rats produced a significant reduction in blood glucose level in rats Ojewole [65].

In Nigeria, the leaves of *Vernonia amygdalina* Del. (VA) and *Azadirachta indica* A. Juss (AI) have been used traditionally as a remedy against diabetes mellitus [66]. Atangwho et al. [66] reported that significant antidiabetic effect of the combination therapy was achieved when VA and AI were combined. The mechanism of action of the combination therapy was proposed as attenuation of oxidative stress, insulin mimetic action and β-cell regeneration. The presence of flavonoids such as luteolin, luteolin 7-*O-β*-glucuronoside, and luteolin 7-*O-β*-glucoside has been shown to be responsible for the antioxidant activity of *Vernonia amygdalina* [67]. The presence of these flavonoids could therefore contribute significantly to the antidiabetic property of *Vernonia amygdalina*.

Etuk and Mohammed [68] reported that 200 mg/kg of *V. amygdalina, C. procera, C. goratensis* and *M. indica* aqueous extracts produced a significant (p < 0.05) reduction in the blood glucose levels of the rats in alloxan-induced diabetic mellitus. In the same vein, *A. leicarpus, C. arereh* and *G. hirsutum* extracts produced a non-significant reduction (p > 0.05) in blood glucose levels in rats after treatment. Similarly, aqueous extracts of *M. Oleifera, S. occidentalis* and *K. senegal‐ ensis* were found to produce a minimal effect (about 4% reduction) on the alloxan-induced hyperglycemia in rats (Etuk and Mohammed, 2009). In summary, Etuk and Mohammed (2009) reported that 200mg/kg body weight of *Vernonia amygdalina* (67%), *Calotropis procera* (59%), *Cassia gorotensis* (53%) and *Magnifera indica* (35%) extracts produced a significant (p < 0.0.5%) reduction in blood glucose levels in diabetic rats while *Angeissus leiocarpus*(30%), Cassia arereh (19%), *Gossypium hirsutum* (17%), *Khaya senegalensis* (4%), *Senna occidentalis* (4%) and *Moringa oleifera* (4%) produced a nonsignificant (p <0.05%) effect.

Previous study showed that aqueous leaves extract of *Psidium guajava* (PG) at 250 mg/kg showed statistically significant hypoglycaemic activity on alloxan-induced diabetic rats [69]. A 4-week supplementation of PG (125 and 250 mg/kg) in streptozotocin (STZ)-induced diabetic rats was shown to protect pancreatic tissues, including islet β-cells, against lipid peroxidation and DNA strand breaks induced by STZ, thereby reducing the loss of insulin-positive β-cells and insulin secretion [70]. More so, PG was found to markedly inhibited pancreatic nuclear factor-kappa B protein expression induced by STZ and restored the activities of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase [70].

1 ml *Allum cepa* solution (0.4 g A. cepa/rat) has been shown to increase the fasting serum highdensity lipoprotein levels and caused reduction of hyperglycaemia in streptozotocin (STZ) diabetic rats [71]. The hypoglycaemic and hypolipidaemic activities of A. cepa were associated with antioxidant activity via decrease superoxide dismutase (SOD) activity while no increased lipid hydroperoxide and lipoperoxide concentrations in diabetic rats treated with A. cepa [71]. In another experiment, onion juices exerted antioxidant and antihyperglycemic effects on alloxan-induced diabetes and consequently ameliorated liver and renal damage associated with alloxan toxicity [72].

the developing countries compared to synthetic drugs because it is safe, less expensive and

1 Drug Metabolism and Toxicology Unit, Department of Biochemistry, College of Medicine,

2 Department of Veterinary Physiology, Biochemistry & Pharmacology, University of Iba‐

3 Biochemistry Unit, Department of Biological Sciences, College of Natural Sciences, Al-Hik‐

4 Oxidative Stress Research Centre, Department of Biomedical Sciences, Faculty of Health & Wellness Sciences, Cape Peninsula University of Technology, Bellville Campus, South Africa

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[2] Shin HJ, Kim JH, Yi JH, Han SW, Kim HJ. Polyuria with the Concurrent manifesta‐ tion of Central Diabetes Insipidus (CDI) & Type 2 Diabetes Mellitus (DM). Electro‐

[3] Smolek MK, Notaroberto NF, Jaramillo AG, Pradillo LR. Intervention with vitamins in patients with nonproliferative diabetic retinopathy: a pilot study. Clinical Oph‐

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, A.J. Esterhuyse4

and E.O. Farombi1\*

Some Selected Medicinal Plants with Antidiabetic Potentials

http://dx.doi.org/10.5772/57230

107

, O.O. Oguntibeju4

\*Address all correspondence to: olatunde\_farombi@yahoo.com

available as a gift of nature.

A.A. Oyagbemi1,2, M. Salihu3

mah University, Ilorin, Nigeria

**Author details**

Nigeria

dan, Nigeria

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Flavonoids from *Ipomoea batatas* leaf (FIBL) was reported to have anti-diabetic activity on alloxan-induced diabetic mice [73]. FIBL treatment (50, 100, and 150 mg/ kg body weight) for 28 days resulted in a significant decrease in the concentration of fasting blood glucose (FBG), total cholesterol (TC) and triglyceride (TG) in diabetes mellitus mice [73]. Also, FIBL signifi‐ cantly increased body weight (bw) and serum high-density lipoprotein cholesterol (HDL-c) level [73]. Stress and inflammation-related p38 mitogen-activated protein kinase activity and tumour necrosis factor-α production of diabetic rats were significantly depressed by *Ipomoea batatas* administration [74]. Similarly, histological examination also revealed improvement of pancreatic β-cells mass after treatments with *Ipomoea batatas* [74]. *Blighia sapida* has also been reported to have several ethnomedicinal uses of which various preparations and extracts have been made for the treatment of diseases such as dysentery, epilepsy, yellow fever and diabetes [75]. Saidu *et al*. [76] recently reported that *Anacardium occidentale* leaves at 300mg/kg body weight showed significant hypoglycaemic activity in alloxan-induced diabetic rats comparable to the standard drug-metformin.
