Long-term anti-diabetic and anti-hyperlipidaemic effects of aqueous stem bark extract of Irvingia gabonensis in streptozotocin-induced diabetic rats

Irvingia gabonensis is used traditionally to treat diabetes. The antidiabetic effect of the seed extract has been demonstrated in human and animal models. This study was designed to evaluate the long-term anti-diabetic and anti-hyperlipidaemic effects of aqueous stem bark extract of I. gabonensis in streptozotocin-induced diabetic rats. Twenty four Wistar rats in three groups, normal control, diabetic control and I. gabonensis treated diabetic rats (TDR) were used for this study. Diabetes was induced in 16 rats by intraperitoneal injection of streptozotocin (STZ) at 65mg/kg body weight. Upon confirmation of diabetes, the treated diabetic rats were orally (by gavage) given aqueous extract of I. gabonensis bark at 200 mg/kg body weight daily for 24 weeks. Body weight was monitored weekly, while fasting blood sugar (FBS) and serum lipid profile (triglycerides, total cholesterol, LDL-cholesterol and HDL-cholesterol) were assessed at specific intervals for 24 weeks. I. gabonensis significantly (P<0.05) reduced the FBS of the treated diabetic rats to normal control levels 2 weeks after the commencement of treatment. The reduction of FBS was sustained till the end of the study (24 weeks). Furthermore, at various stages of monitoring, the extract reduced the STZ-induced elevation of serum triglycerides, total cholesterol and LDL-cholesterol, and significantly (p<0.05) increased the STZ-induced decrease in HDL-cholesterol. Our study concludes that aqueous stem bark extract of I. gabonensis possess significant long-term anti-diabetic and hypolipidaemic effects. These anti-hyperlipidaemic effects as well as the presence of phytochemicals with recognizable anti-oxidant effects will be useful in the treatment of diabetic complications

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

Editorial: Announcing a New Editor, African Journal of Reproductive Health

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Long term hypolipidaemic and anti-atherogenic effects ofCarica papaya Linn. administration on normal rabbits

Carica papaya Linn. (Caricaceae) is commonly called paw-paw and papaya. It is used widely in the tropics and sub-tropics as food and medicinal plant. Various parts of the plant are used in folkloric medicine for the treatment of indigestion, asthma, beriberi, jaundice, as well as for wound dressing. This study was designed to assess the long term (24 weeks) effects of daily oral administration of C. papaya aqueous leaf extract (at 200 mg/kg body weight) on the serum lipid profile and other atherogenic indices of normal rabbits. Total cholesterol, total triglycerides, LDL-cholesterol, HDL-cholesterol, atherogenic and coronary risk indices were monitored periodically for 24 weeks. Administration of C. papaya leaf extract caused significant reductions in total cholesterol, triglycerides and LDL-cholesterol. Also, from week 10 of this study, HDL-cholesterol concentration increased in the C. papaya treated rabbits. Atherogenic and coronary risk indices were not altered. The antihyperlipidaemic effect observed in this study may be attributed to the nutrients and phytochemicals found in C. papaya.Keywords: Lipid profile; Atherogenic index; Coronary risk index; Carica papaya; Medicinal plants; Hypolipidaemi

Effects of Vitamin C on Kidney and Bone of Rats Exposed to Low Doses of Cadmium

ABSTRACT: In this study, the effect of vitamin C on cadmium-induced toxicity was investigated. Wister rats were exposed to cadmium (as CdSO4.8H2O), by sub-cutaneous injection, at doses of 1.0, 2.0 and 3.0 μg/kg body weight, with or without vitamin C supplementation, for four weeks. Serum alkaline phosphatase activity of the group of rats not supplemented vitamin C (group III) significantly (p<0.05) increased, all the groups supplemented with vitamin C also had significantly (p<0.05) increased serum alkaline phosphatase. The bone protein level and serum calcium of the vitamin C untreated group of rats, significantly (p<0.05) decreased relative to control. The bone calcium of the vitamin C treated rats significantly (p<0.05) decreased (group IIIc from 2896.30 ± 344.64 mg Ca/dl to 1049 ± 101.43 mg Ca/dl) while the bone phosphate of this same group of rats, significantly (p<0.05) increased. For some parameters evaluated, such as serum calcium and bone protein concentration, the effects of cadmium on the vitamin C treated rats were less pronounced, indicating that vitamin C may be protective against cadmium-induced toxicity

Long-term effects of three hypoglycaemic plants ( Irvingia gabonensis , Urena lobata and Carica papaya ) on the oxidative status of normal rabbits

Medicinal plants have been recognized to have therapeutic effects and they may also have toxic side effects. Our previous studies have shown that Irvingia gabonensis , Urena lobata and Carica papaya , locally used in Nigeria to treat diabetes, possess long term hypoglycaemic and anti-obesity effects on normal rabbits. In this study, the long term effects of aqueous extracts of I. gabonensis bark, U. lobata root and C. papaya leaves on the oxidative status of normal rabbits were monitored at specific intervals in the serum for 24 weeks, and in the tissues. Oxidative status was determined by measuring activities of superoxide dismutase (SOD) and catalase (CAT), and the concentration of malondialdehyde (MDA). Significant (p<0.05) decreases were observed in some weeks in the serum MDA levels; also, liver and pancreatic MDA levels were significantly (p<0.05) lower for all treated rabbits. SOD and catalase activities in the serum and tissue of the rabbits treated with the medicinal plants were generally higher or statistical similar to control. Findings in this study showed that these hypoglycemic medicinal plants did not exert oxidative damage; in some instances, particularly in the pancreas, they were found to be protective against oxidative damage

Editorial: COVID-19: Perspectives and Reflections from Africa

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Editorial: Scoping AJRH operations and future directions

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