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.

The current study sought to investigate the capacities of single and combinatorial herbal formulations of leaf extracts of Acanthus montanus, Asystasia gangetica, Emilia coccinea, and Hibiscus rosasinensis to reverse hyperglycemia and dyslipidemia in alloxan-induced diabetic male rats. Phytochemical composition of the herbal extracts, fasting plasma glucose concentration (FPGC), and serum lipid profile (SLP) of the rats were measured by standard methods. The relative abundance of phytochemicals in the four experimental leaf extracts was in the following order: flavonoids > alkaloids > saponins > tannins. Hyperglycemic rats (HyGR) treated with single and combinatorial herbal formulations showed evidence of reduced FPGC compared with the untreated HyGR and were normoglycemic (FPGC < 110.0 mg/dL). Similarly, HyGR treated with single and combinatorial herbal formulations showed evidence of readjustments in their SLPs. Generally, HyGR treated with triple herbal formulations (THfs) exhibited the highest atherogenic index compared with HyGR treated with single herbal formulations (SHfs), double herbal formulations (DHfs), and quadruple herbal formulation (QHf). The display of synergy or antagonism by the composite herbal extracts in ameliorating hyperglycemia and dyslipidemia depended on the type and number of individual herbal extract used in constituting the experimental herbal formulations. Furthermore, the capacities of the herbal formulations (SHfs, DHfs, THfs, and QHf) to exert glycemic control and reverse dyslipidemia did not follow predictable patterns in the animal models.