An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

© 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio

Oxidative stress in pregnancies complicated by diabetes

The placenta is essential for normal foetal metabolism and growth. However, maternal diabetes is an unfavourable environment for embryonic and fetoplacental development, which may disrupt normal foetal programming, leading later to metabolic disease. Additionally, an adverse in utero environment may lead to foetal congenital anomalies. Existing diabetes before pregnancy (pregestational type 1 and or type 2 diabetes mellitus) may have negative effects on the embryonic development, while gestational diabetes mellitus (GDM) that occurs during late stages of pregnancy may affect the growth and maturation of the foetus. Many of the damaging effects of diabetes in pregnancy have been attributed to oxidative stress. Reactive oxygen and nitrogen species are by-products of a number of important biological pathways of pregnancy, including embryo development, implantation, angiogenesis, placental development and function. In healthy pregnancies, these reactive oxygen and nitrogen species can be controlled to ensure no damage ensues. However, in pregnancies complicated by diabetes, their excessive production and/or a reduction in antioxidant defence mechanisms results in a number of damaging outcomes. Animal models of diabetes in pregnancy have provided supportive evidence of reactive oxygen and nitrogen species generation and their damaging effects, which are dependent on the developmental stage. In this chapter, we will review the available data on oxidative stress in human diabetic pregnancies as well as in animal models of diabetes in pregnancy during early gestation, fetoplacental development and the perinatal period, as well as on its postnatal consequences. Human and animal data supportive of antioxidant treatments will be also discussed