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studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals.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

Determination of the optimal pH for doxorubicin encapsulation in polymeric micelles

Hypothesis The anticancer drug doxorubicin hydrochloride (DX) shows a high solubility in aqueous media thanks to the positive charge in the ammonium group. This feature, however, affects the drug encapsulation in the hydrophobic domains of polymeric micelles (PMs) used for the targeted delivery of the drug. At basic pH, DX deprotonates but also acquires a negative charge in the phenolic groups of the anthracycline structure. Both the efficiency and the rate of encapsulation will be increased by choosing an appropriate pH such that the drug molecule is in neutral form. Experiments An optimal pH for the encapsulation of the DX in PMs based on commercial poloxamers and on the diblock copolymer methoxy-poly(ethylene glycol)17-b-poly(ε-caprolactone)9 was determined by fluorescence spectroscopy, following the time evolution of both the intensity ratio of the first and the second emission bands of DX and its fluorescence lifetime, both sensitive to the environment polarity. Intracellular delivery of PMs encapsulated drug was followed by Confocal Scanning Laser Microscopy (CSLM). Cell viability was assessed with the sulforhodamine B (SRB) assay. Findings By adjusting pH to 8.1 a high yield of incorporation of DX in the PMs was achieved coupled to an appreciable increase (one order of magnitude) in the drug encapsulation rate. In-vitro tests in selected cancer cell lines showed the slow release of the drug and a delay in the cytotoxic response in comparison to free DX as detected by CSLM and SRB assay. The proposed methodology paves the way for a greener, faster and more efficient encapsulation of DX in PMs

Co-treatment Effect of Syzygium cumini (L.) Skeels on Indomethacin Induced Gastric Ulcer on Mice Model

Syzygium cumini (L.) Skeels or SCC originally from India and Southeast Asia, commonly used as a medicinal and acted as antioxidant and anti-inflammatory plant. Indomethacin, which is a part of nonsteroidal anti-inflammatory drugs (NSAIDs) family, induced gastric damage and perforation through the excess generation of reactive oxygen species (ROS). This research focus on co-treatment administered between SCC and indomethacin in the subsequent 7 days and evaluated on oxidative damage, inflammatory parameter and epidermal growth factor (EGF) receptor. SCC showed a concentration and dose dependent reduction in ulcer index (UI) values leading to the increasing of inhibition percent when compared to indomethacin treated mice, confirmed by photographer which showed maximum efficacy on day 5 of treatment. On day 1 and day 3 of ulceration, malondialdehyde (MDA), oxidized glutathione (GSSG), nitrile contents and tumor necrosis factor-alpha (TNF-α) were increased. Gastric wall mucus and glutathione peroxidase (GPx) were down. After that gastric mucosa were recovered by healing processed and were regenerated the mucosal cap to promote EGF receptor. SCC was increased the up-regulation of COX-1 enzyme resulting in down-regulation to COX-2 expression at day 3 of ulceration. At day 5 and 7, the gastric ulceration were regenerated themselves. These all results indicated that SCC have a great protective effect against indomethacin induced gastric ulcer in in-vivo co-treatment model.</jats:p