**9. Antioxidant activity of medicinal plants with antidiabetic activity**

One of the major pathogenic mechanisms of diabetes mellitus include generation of oxidative stress, increase generation of free radicals and an impaired antioxidant defence system with concomitant imbalance of the oxidant/antioxidant status [54]. Inhibition of this cascade of oxidative processes has been reported to prevent the onset and development of diabetic complications [55]. Antidiabetic plants have been documented to scavenge free radicals, quench electronically excited compounds, reduce hydroperoxide formation, and attenuate production of reactive oxygen species (ROS) through modulation of several enzymes including xanthine oxidase, cyclooxygenase, lipoxygenase, microsomal monooxygenase, NADH oxidase and mitochondrial succinoxidase [56]. More so, plant phytonutrients such as poly‐ phenols are known to enhance the endogenous antioxidative system, improve oxidant antioxidant balance, prevent oxidative damage, decrease lipid peroxidation, increase plasma total antioxidant capacity and induce antioxidant enzymes including superoxide dismutase, catalase and glutathione peroxidase [57].

**10. Plant phytochemicals associated with antidiabetic activity**

**Botanical Family**

*Senna occidentalis* Fabaceae

*Khaya senegalensis* Meliaceae *Acacia nilotica* Mimosaceae *Vernonia amygdalina* Asreraceae *Fiscus thonnigii* Moraceae

*Mangifera indica* Anacardiaceae

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*Euphorbia convuludiodes* Euphobiaceae

*Angeissus leiocarpus* Combretaceae

*Gossypium hirsutum* Malvaceae *Vitillarta paradoxa* Sapotaceae *Anacardium occidentalis* Anacardiaceae *Anana senegalensis* Anonaceae *Psidium guajava* Myrtaceae *Moringa oleifera* Mringaceae *Azadirachata indica* Meliaceae *Alluvium cepa* Liliaceae *Ctrus medica* Rutaceae *Parkta filicoidea* Mimosaceae

*Allium sativum* Liliaceae

**Table 2.** Some plant families reported for antidiabetic activity

Adapted from Etuk et al., 2010

*Balanites aegyptiaca* Zygophyliaceae *Bauhinia reticulate* Casalpiniaceae Casalpiniaceae

Photochemicals or phytonutrients are chemical compounds that occur naturally in plants that have protective or disease preventive properties [58]. Each type of fruit or vegetable may contain hundreds of phytochemicals. They have been reported to show multiple beneficial effects in combating diabetes and diabetes related complications [58]. The widest known


**Table 2.** Some plant families reported for antidiabetic activity

*plants in this category include Cecropia obtusifolia, Marrubium vulgare, Asteracantha longifolia Nees L., Panax quinquefolius L, Gymnema Sylvestre, Phyllanthus amarus, Opuntia streptacantha Lem*. They were found to produce beneficial effects on carbohydrate and lipid metabolisms when administered as an adjunct on patients with type 2 diabetes [44]. These plants have been reported to improve glucose tolerance in healthy human subjects and diabetic patients, caused significant reduction in blood glucose, glycosylated haemoglobin and glycosylated plasma

**8. General mechanism (s) of action of medicinal plants with antidiabetic**

Different mechanisms of action of medicinal plants with anti-diabetic have been extensively described. These include inhibition of renal glucose reabsorption [46], stimulation of insulin secretion from beta cells of islets or/and inhibition of insulin degradative processes, reduction in insulin resistance [47] regenerating and/or repairing pancreatic beta cells with increasing the size and number of cells in the islets of Langerhans [45]. Stimulation of insulin secretion [48] and stimulation of glycogenesis and hepaticglycolysis [49] with antidiabetic plants is well established. Also, protective effect on the destruction of the beta cells and improvement in digestion along with reduction in blood sugar urea has been documented [50]. Prevention of pathological conversion of starch to glucose, and inhibition of β-galactocidase, α-glucocidase and alpha-amylase with concomitant capacity to lower cortisol has also been reported [51-52]. Antioxidant activity of antidiabetic plant against oxidative stress which is involved in pancreatic ß-cell dysfunction has been reported as one of the mechanisms of action of anti‐ diabetic plants [53]. Similarly, some plant families reported for antidiabetic activity are shown

**9. Antioxidant activity of medicinal plants with antidiabetic activity**

One of the major pathogenic mechanisms of diabetes mellitus include generation of oxidative stress, increase generation of free radicals and an impaired antioxidant defence system with concomitant imbalance of the oxidant/antioxidant status [54]. Inhibition of this cascade of oxidative processes has been reported to prevent the onset and development of diabetic complications [55]. Antidiabetic plants have been documented to scavenge free radicals, quench electronically excited compounds, reduce hydroperoxide formation, and attenuate production of reactive oxygen species (ROS) through modulation of several enzymes including xanthine oxidase, cyclooxygenase, lipoxygenase, microsomal monooxygenase, NADH oxidase and mitochondrial succinoxidase [56]. More so, plant phytonutrients such as poly‐ phenols are known to enhance the endogenous antioxidative system, improve oxidant antioxidant balance, prevent oxidative damage, decrease lipid peroxidation, increase plasma total antioxidant capacity and induce antioxidant enzymes including superoxide dismutase,

proteins comparable to an oral hypoglycaemic drug [45].

102 Antioxidant-Antidiabetic Agents and Human Health

**property**

below (Table 2).

catalase and glutathione peroxidase [57].
