ABSTRACT
The standardisation of serotherapy is necessary in Africa mainly because of the frequency of envenomations and the lack of alternative treatments. Comparative titrations of FAV-Afrique (Aventis Pasteur), Polyvalent serum (Serum Institute of India = SII) and Polyvalent antivenin (South African Vaccine Fabricants Ltd = SAIMR) were carried out on venoms of Echis ocellatus from Cameroun, E. ocellatus from Mali, E. leucogaster and Naja melanoleuca. The 50% protective doses (ED50) of the antivenoms were given according either to i) the in vitro method which consists of inoculating 5 batches of 5 mice with a mixture containing 3 DL50 of venom and increasing volumes of antivenom incubated for 30 mn at 37 degrees C and ii) the in vivo method which consists of successive administration of venom and then antivenom after a 30 to 60 mn interval. The three antivenoms showed a similar efficacy against all the Echis venoms. Interestingly, the SAIMR proved to be effective against the venom of E. leucogaster and E. ocellatus although no venom of Echis was used to immunise horses during the preparation of antivenom. Conversely, this paraspecificity did not exist with the Naja melanoleuca venom against which FAV Afrique showed a higher efficacy. The electrophoresis pattern of FAV-Afrique performed on acetate gel strips showed only one protein fraction (76 g.l-1), whereas both the SII and SAIMR antivenoms showed four fractions whose protein concentrations was respectively 64 g.l-1 and 145 g.l-1.
Subject(s)
Antivenins/chemistry , Antivenins/therapeutic use , Elapid Venoms/toxicity , Snake Bites/therapy , Titrimetry/methods , Viper Venoms/toxicity , Africa South of the Sahara , Animals , Cameroon , Disease Models, Animal , Drug Evaluation, Preclinical , Electrophoresis, Cellulose Acetate , Lethal Dose 50 , Mali , Mice , Therapeutic Equivalency , Time FactorsABSTRACT
The decoction of the rhizome of Cyperus articulatus is empirically used in several African countries in the treatment of a wide variety of human diseases. Studies were conducted in mice in order to determine scientifically the pharmacological properties of this medicinal herb. At the same time, the qualitative chemical characterisation of the total extract showed that C. articulatus contains flavonoids, saponins, tannins, terpenes and sugars. The total extract of the rhizome of C. articulatus does not appear to possess either anaesthetic or paralysing effects. In contrast, spontaneous motor activity is significantly reduced by the extract. However, when compared to diazepam, C. articulatus does not seem to have muscle relaxant effects. When associated with sodium thiopental or diazepam, the total extract facilitates sleep induction, and increases the total sleep time without any concomitant analgesic effect. These observations suggest that the rhizome of C. articulatus has pharmacological properties similar to those of sedatives. The sedative actions probably explain at least part of the therapeutic efficiency claimed for this plant in traditional medicine.
Subject(s)
Hypnotics and Sedatives/pharmacology , Motor Activity/drug effects , Plant Extracts/pharmacology , Plants, Medicinal , Sleep/drug effects , Animals , Female , Humans , Male , Medicine, African Traditional , Mice , Muscle Relaxation/drug effects , Pain/prevention & control , Plant Roots/chemistryABSTRACT
Dendroaspis jamesoni (Elapidae) and Echis oceliatus (Viperidae) are responsible for most of severe evenomation in Cameroon. Toxicity of venoms of these two species has been measured using mice according to the method of Spearman & Kàrber. The effect on experimental envenomation of various drugs (atropine, promethazine, neostigmine, hydrocortisone, pentosane sulfuric polyester, heparin, tranexamic acid and aminocaproic acid) and plant extracts (Schumanniophyton magnificum, Bidens pilosa, Securidaca longepedunculata and Garcinia lucida) has been observed associated or not with the antivenom lpser Afrique (SAV). The venom of D. jamesoni contains neurotoxins agonizing and antagonising acetylcholine. The toxicity of the venom did not depend on the route of injection. Atropine, promethazine, neostigmine and hydrocortisone protected animals against a venom dose up to 2 LD50. Moreover, atropine and promethazine potentiated the SAV. Similar results have been obtained with extracts from S. magnificum and B. pilosa. The venom of E. ocellatus induces haemorrhage and necrosis. The toxicity increased by 3-fold when the venom was injected through intravenous or intraperitoneal route, compared to intramuscular route. Pentosane sulfuric polyester and tranexamic acid protected mice against doses up to 3 LD50. Pentosane sulfuric polyester, hydrocortisone, heparin and aminocaproic acid increased the SAV protective titre by 50%. However, tried plant extracts weakly antagonised the venom and did not potentiate the SAV.
