Background: Diabetes mellitus (DM) is a metabolic disorder that is characterized by hyperglycemia and glucose intolerance, which is associated with impaired insulin secretion and peripheral sensitivity and eventual b-cell dysfunction. This review summarized the major metabolic pathways leading to both microvascular and macrovascular complications in DM, with a view of highlighting the enzymes involved and the possible inhibition of the enzymes facilitating these processes as a measure of diabetic control. Methods: Data used in writing this review were sourced online from scientific search engines such as Google Scholar, Scopus, EMBASE, PubMed, ResearchGate, Mendeley, Medline, and SpringerLink, using keywords such as 'diabetic complications', 'hyperglycemia-induced diabetic mechanisms', 'diabetic enzymes' and 'diabetic enzyme inhibitors'. A total number of 109 references published online between 1990 and 2020 were generated and cited in this review. Results: The most scourging and dilapidating effects of DM as well as associated vascular complications are classified into four categories viz.: nephropathy, retinopathy, neuropathy and cardiovascular disease. Hyperglycemia, which is associated with uncontrolled DM, elicits abnormal metabolism such that the enzymes involved in metabolic events leading to diabetic complications are expressed and amplified. The disorders associated with DM are linked to various metabolic pathways facilitated by enzyme activities of the polyol pathway, hexosamine biosynthetic pathway, glucose autoxidation as well as increased synthesis of advanced glycation end-products (AGEs), hexokinase-2 driven glycolytic overload, increased activities of the cyclooxygenase (COX), lipoxygenase (LOX) and pyruvate kinase (PKC) enzymes. The inhibition of the enzymes involved in these pathways could serve to mitigate and arrest diabetic complications. Conclusion: Thus, suitable inhibitors for enzymes involved in DM metabolic events could serve as panaceas against DM complications, which will add to the growing list of new and more efficacious antidiabetic drugs.

Background Cancer is currently the leading cause of death globally and the number of deaths from cancer is on the rise daily. Medicinal plants have been in continuous use over the years for the management of cancer, particularly, in most developing countries of the world including Nigeria. The use of synthetic drugs for the treatment of cancer is often accompanied by toxic side effects. Thus, the alternative use of readily available and inexpensive medicinal plants is the panacea to the toxic side effects associated with synthetic drugs. Main body The present review summarized the anticancer activity of 51 medicinal plants that are widespread in all regions of Nigeria. Furthermore, the proposed anticancer pharmacological actions as well as the anticancer bioactive compounds, the type of cancer cell inhibited, the plant parts responsible for the anticancer activity, and the nature of the extracts used for the studies were discussed in this review. The 51 Nigerian medicinal plants were reported to exhibit anticancer activities of the prostate, cervices, lung, skin, colon, esophagus, blood, ovary, central nervous system/brain, breast, stomach, pancreas, larynx, and kidney. The major classes of bioactive compounds indicated to be responsible for the anticancer activity include the polyphenols, flavonoids, alkaloids, saponins, triterpenes, tannins, and quinones. The major anticancer pharmacological actions of these bioactive compounds were antiproliferative, cytotoxic, cytostatic, antimetastatic, apoptotic, and antioxidative as well as provoked cell cycle arrest, inhibition of angiogenesis and reduction of cancer cell viability. Conclusion The Nigerian medicinal plants can be harnessed to provide for readily available and inexpensive anticancer drugs in the future because the plants reported in this review showed promising anticancer activity.

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This study was carried out to investigate heavy metals concentrations: lead (Pb), cobalt (Co), cadmium (Cd), zinc (Zn), nickel (Ni), copper (Cu) and manganese (Mn) in Musa paradisiaca (plantain), Zea mays (maize), Cucumeropsis manii (melon), Manihot esculenta (cassava) and soil samples from dumpsites in Onne, Eleme Local Government Area, Rivers State, Nigeria. The plant leaf and soil samples were measured for heavy metals concentrations using atomic absorption spectrophotometer. The health risk index (HRI) of the heavy metals following the consumption of these plant materials by the populace was estimated using standard protocols. The heavy metals concentrations in the leaf samples ranged from 0.012-14.712 mg/kg, whereas those of the soil samples were within the range of 2.543-16.459 mg/kg. Cd concentrations in the soil and leaf samples were above the maximum permissible level according to the World Health Organization (WHO). The bioaccumulation of the heavy metals followed the trend: (M. paradisiaca) Zn > Pb > Co > Mn > Cu > Cd > Ni; (Z. mays) Mn > Pb > Co > Zn > Cu > Cd > Ni; (C. mannii) Mn > Co > Pb > Cu > Zn > Cd > Ni; (M. esculenta) Zn > Pb > Mn > Cu > Co > Ni > Cd. The highest bioaccumulation of the heavy metals occurred in M. esculenta. The estimated HRI of Pb in M. esculenta was greater than 1. HRI > 1 was indicative that the consumer population is not safe. Cassava-based meals from the dumpsites contained Pb at toxic level, whereas Co, Cd, Zn, Ni, Cu, and Mn concentrations in plantain-, maize-and melon-based meals were relatively within safe limits.