|ISSN No. 1606-7754 Vol.10 No.1 April 2002|
Medicinal plants used in the treatment of diabetes in Morocco
Mohamed Bnouham, Hassane Mekhfi, Abdelkhaleq Legssyer
Laboratoire de Physiologie et Pharmacologie Cellulaire. Department de Biologie - Faculte des Sciences. Universitie Mohamed Premier. B.P. 524 - Oujda, Morocco
The present review shows a listing of medicinal plants used in phytotherapy of diabetes and those experimentally studied as hypoglycaemic in Morocco. The review is presented as 3 tables. The first one includes the taxonomic classification of the plant, the popular names in Morocco, the parts used, the mode of preparation and the other medicinal uses and toxicity. The second table summarises the experiments done by Moroccan researchers to confirm the hypoglycemic activity of the medicinal plants. It also describes the methodology used, and the magnitude of the hypoglycemic activity. The third table lists the toxicological studies carried out with plants reported to be toxic. The large number of plants described in this review (94 species belonging to 38 families) demonstrated the prevalence of phytotherapy in Morocco. The plant families which contained the most commonly used species for their antidiabetic effects are: Compositae (18 species), Lamiaceae (14 sp.), Leguminosae (8 sp.), Liliaceae (5 sp.), Apiaceae (5 sp.), and Graminae (4 sp.). Among these medicinal plants, 17 are toxic, the most known being: Daphne gnidium, Nerium oleander, Ferula communis, Peganum harmala and Citrullus colocynthis.
Keywords : Hypoglycemia, Medicinal plants, phytotherapy, diabetes mellitus, Morocco.
Diabetes mellitus is one of the most common metabolic diseases in Morocco. Indeed, its incidence is about 10 % in this country. In certain regions of Morocco the incidence of diabetes mellitus has reached 13.3%.1 In a recent survey in eastern Morocco, about 60 % of non-insulin-dependent diabetics were found to resort to the use of medicinal plants to treat their disease.2 In fact, phytotherapy has been widely used by the Moroccan population since time immemorial. This practice continues to be prevalent in the cities as well as in the rural environment because of the low cost and the easy availability of medicinal plants in all the markets in the country. However, the studies on antidiabetic plants used in Morocco are relatively recent and has begun to evolve in the last few years. Moreover, until recently, there has been no extensive documentation of data on antidiabetic plants in Morocco.
The aim of the review is to make a list of work done on plants considered as antidiabetic in Morocco. This index is a collection of experimental studies, reports of investigations and documents published in Morocco on hypoglycemic and antidiabetic plants.
Results and discussion
In this review, a listing of data on medicinal plants used in the treatment of diabetes is presented in three tables. The first one contains a list of plants used in phytotherapy in Morocco, the scientific name and the family of the plant, its popular names in Morocco, the parts used, the mode of preparation, other medicinal uses and toxicity. The second table represents the informations on experimental work done to confirm hypoglycemic activity. It describes the methodology used, the animal models, the doses and the magnitude of the hypoglycemic activity of the plant. The third table represents a listing of the plants reported to be toxic and some toxicological studies.
In Morocco, a wide range of medicinal plants is used in folk medicine for the treatment of different diseases. There are several dozen botanical species widely used for the treatment of diabetes. Some of these are now well known by the scientific community; for example Trigonella foenum grecum, Allium sativum, Artemisia herba alba and Citrullus colocynthis.
The families which contain the species of medicinal plants most used for their antidiabetic effects are the following: Compositae (18 species), Lamiaceae (14 sp.), Leguminosae (8 sp.), Liliaceae (5 sp.), Apiaceae (5 sp.), and Graminae (4 sp.).
There are two types of diabetes, the insulin-dependent diabetes with hypo-insulinemia and non-insulin-dependent diabetes with hyper-insulinemia. One can also induce a transient hyperglycemia orally or subcutaneously. On the other hand one can produce insulin-dependent diabetes experimentally using agents such as alloxan (actually this drug is seldom used because it doesn't selectively destroy the ß cells of Langerhans) and streptozotocin that destroys ß cells selectively. Many authors have explained the antidiabetic effect of plants. They may stimulate insulin secretion from ß cells and induce regeneration, revitalization and/ or hyperplasia of the ß cells. Moreover, extracts of antidiabetic plants can act by imitating the action of insulin, an "insulin-like action". Antidiabetic plants can act by supplying ß cells with the necessary elements (Cu++, Mg++, Ca++). These plant extracts can also reduce the action of insulinase, an enzyme that destroys the insulin in the liver.
On the other hand, extracts from antidiabetic plants may act on glucose homeostasis in a non-insulin-dependent diabetes model. They can decrease the level of glucagon, induce a decrease in the intestinal absorption of glucose and/or reduce the peripheral use of glucose. Moreover, they may act on liver enzymes causing stimulation of glucogenogenesis and/or inhibition of the glycogenolysis.
The following antidiabetic medicinal plants, cited in this review,17 are toxic: Daphne gnidium, Nerium oleander, Ferula communis, Peganum harmala, Globularia alypum, Lupinus albus, Aloe socotrina, Androcymbium garmineum, Androcymbium intermedium, Nigella sativa, Crataegus oxyacantha, Ruta montana, Artemisia herba alba, Chenopodium ambrosioides, Haloxylon scoparium, Launea arborescens and Citrullus colocynthis (see table 3).
Table 1: Presentation of hypoglycemic plants used in traditional medicine as anti-diabetics, with scientific name, popular name, used parts, preparation, other medicinal uses and the toxicity. (table in pdf)
Table 2: Presentation of hypoglycemic plants experimentally studied in Morocco, with scientific name, used parts and the methodology used for experimentation.(table in pdf)
Table 3 : Presentation of hypoglycemic plants used in traditional medicine in Morocco as antidiabetics, reported to be toxic.(table in pdf)
The plants described as toxic represent about 18% of the medicinal plants cited in this study. The signs of toxicity are variable. In general, the poisonous plants are known by shepherds. In the same way, animals escape the poisonous plants because in general they have a bitter taste. Very few toxicological studies have been carried out on antidiabetic plants.38 It is important to note that the traditional utilization, of medicinal plants, many toxic plants are used at a low dose and/or treated before being used in order to eliminate the poisonous components of the plant (by cooking, decoction, etc.). It is notable that several toxic plants are used in traditional medicine through fumigation or by external use (cutaneous in most cases).4, 6
Consequently, it is necessary to carry out toxicological investigation of all plants empirically used in order to avoid the risk of the side effects related to phytotherapy.
There is a meaningful evolution of the experiments on the medicinal plants in Morocco. However, mechanism of action and toxicity of the potentially antidiabetic plants have not been studied. Finally, this review may be useful to for researchers interested in antidiabetic, plants from Morocco.