Receptor-mediated production of inositol 1,4,5-trisphosphate (InsP 3 ) initiates Ca 2+ release and is responsible for cytosolic Ca 2+ oscillations. InsP 3 oscillations have also been observed in some cells. One of the enzymes controlling InsP 3 catabolism, the InsP 3 3-kinase, is stimulated by Ca 2+ ; this regulation is presumably part of the reason for InsP 3 oscillations that have been observed in some cells. Here, we investigate the possible role of Ca 2+ -activated InsP 3 catabolism on the characteristics of the InsP 3 -induced Ca 2+ oscillations. Numerical simulations show that if it is assumed that the Ca 2+ -independent InsP 3 catabolism is predominant, Ca 2+ oscillations remain qualitatively unchanged although the relative amplitude of the oscillations in InsP 3 concentrations becomes minimal. We tested this prediction in hepatocytes by masking the Ca 2+ -dependent InsP 3 catabolism by 3-kinase through the injection of massive amounts of InsP 3 5-phosphatase, which is not stimulated by Ca 2+ . We ¢nd that in such injected hepatocytes, Ca 2+ oscillations generated by modest agonist levels are suppressed, presumably because of the decreased dose in InsP 3 , but that at higher doses of agonist, oscillations reappear, with characteristics similar to those of untreated cells at low agonist doses. Altogether, these results suggest that oscillations in InsP 3 concentration due to Ca 2+ -stimulated InsP 3 catabolism do not play a major role for the oscillations in Ca 2+ concentration. ß 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

Launaea taraxacifolia is a leafy vegetable of the family of Asteraceae (Compositae) found in several countries in West Africa including Ghana, Benin and Nigeria. The plant leaves are eaten either fresh as salad or cooked as sauces. They are also consumed as infusion to fight against several diseases including non-communicable diseases such as diabetes and hypertension. Several studies have been conducted in Ghana, Nigeria on the nutritional and medicinal values of this plant but no study has yet been conducted in Benin on the virtues of this plant. In this work we have achieved the phytochemical characterization and evaluated the cytotoxicity as well as hypolipidemic and antioxidant effects of the ethanol-aqueous extracts of Launaea taraxacifolia leaves. Cytotoxicity and hypolipidemic activities have been performed on HepG2 cells; the antioxidant effect has been performed on the PLB985 cells. The results showed that the ethanol-aqueous extracts of Launaea taraxacifolia leaves contained the following metabolites: catechic tannin, flavonoids, phenolic acids, mucilage and leucoanthocyanins. Only very high concentrations (>20 mg/ml) of leaves extracts are toxic for HepG2 cells. Launaea taraxacifolia leaves have significant antioxidant and hypolipidemic activities.

BackgroundSince ancient times, invertebrates have played an important role in the traditional medicine in many parts of the world. In south-eastern Benin, more specifically in the Plateau Department, invertebrates are widely used in folk medicine. However, studies on their therapeutic use has been neglected and their magical–religious purposes are poorly understood. The present study aims to document traditional knowledge related to the use of invertebrates for medicinal and magical–religious purposes by traditional healers and indigenous people of Plateau Department.MethodsAn ethno-sociological survey was conducted with 145 informants (80 traditional healers, 12 merchants of medicinal animals and 53 households) belonging to six ethnic groups, in 20 villages located in Plateau of Benin. Data were collected through the participatory rural appraisal method involving individual interviews and direct observations with semi-structured questionnaires. The collected data regarding various medicinal and magical–religious uses of invertebrates were analysed through informant consensus factor (ICF), use value (UV) and, fidelity level (FL).ResultsA total of 20 families and 38 species of invertebrates, distributed among 6 taxonomic categories, were found to be used to treat 50 different ailments. Insects occupied 64.7% of the total invertebrates listed. The African earthworm Eudrilus eugeniae K. and African giant snail Achatina achatina L. had the highest use values. The highest ICF value (1.0) was cited for diseases of the blood or blood-forming organs. A principal component analysis (PCA) revealed the influence of ethnic groups in the diseases treated with invertebrates. The highest FL (100%) was recorded for 12 invertebrate species treating various ailments. Most of invertebrate-based remedies were associated with plant species. The mode of administration was mainly oral and topical. Most of the invertebrate drugs were traditionally collected in nature or imported, mainly from Nigeria. In addition, 7 magical–religious practices are documented.ConclusionsOur results reveal that several invertebrate species play an important role in healing practices and magical–religious rituals in the Plateau Department. We suggest further studies to confirm the presence of any bioactive compounds on invertebrate species use in traditional medicine. In addition, this study highlights the need for ecological investigations of these species, in order to develop strategies for their conservation and sustainable use.