Traditional health practitioner and the scientist: bridging the gap in contemporary health research in Tanzania.

Traditional health practitioners (THPs) and their role in traditional medicine health care system are worldwide acknowledged. Trend in the use of Traditional medicine (TRM) and Alternative or Complementary medicine (CAM) is increasing due to epidemics like HIV/AIDS, malaria, tuberculosis and other diseases like cancer. Despite the wide use of TRM, genuine concern from the public and scientists/biomedical heath practitioners (BHP) on efficacy, safety and quality of TRM has been raised. While appreciating and promoting the use of TRM, the World Health Organization (WHO), and WHO/Afro, in response to the registered challenges has worked modalities to be adopted by Member States as a way to addressing these concerns. Gradually, through the WHO strategy, TRM policy and legal framework has been adopted in most of the Member States in order to accommodate sustainable collaboration between THPs and the scientist/BHP. Research protocols on how to evaluate traditional medicines for safety and efficacy for priority diseases in Africa have been formulated. Creation of close working relationship between practitioners of both health care systems is strongly recommended so as to revamp trust among each other and help to access information and knowledge from both sides through appropriate modalities. In Tanzania, gaps that exist between THPs and scientists/BHP in health research have been addressed through recognition of THPs among stakeholders in the country's health sector as stipulated in the National Health Policy, the Policy and Act of TRM and CAM. Parallel to that, several research institutions in TRM collaborating with THPs are operating. Various programmed research projects in TRM that has involved THPs and other stakeholders are ongoing, aiming at complementing the two health care systems. This paper discusses global, regional and national perspectives of TRM development and efforts that have so far been directed towards bridging the gap between THPs and scientist/BHP in contemporary health research in Tanzania.

Traditional healer's knowledge and implications to the management and control of HIV/AIDS in Arusha; Tanzania

Due do limited coverage of conventional health care services in Tanzania; a number of HIV/AIDS patients are consequently being cared for and managed by traditional healers. Knowledge of 132 traditional healers on HIV/AIDS was assessed through a questionnaire that sought among other things the symptoms that these traditional healers associate with HIV/AIDS. Seventy-seven (61) healers claimed to be treating HIV/AIDS patients. Twenty-five percent (33 healers) had poor; 52.3(69 healers) had moderate; 22.7(30 healers) had good knowledge of HIV/AIDS. Sixty-nine(52) among the traditional healers mentioned six and thirty (23) healers mentioned more than six symptoms associated with HIV/AIDS as outlined by the WHO clinical HIV staging system. Almost all the healers were aware that HIV/AIDS is spread sexually and through body fluid contact and claimed that precautionary measures are taken to avoid spread of the disease. Knowledge on HIV/AIDS infection from mother to child during pregnancy; at delivery and through breastfeeding was poor for most healers. It seems most traditional healers meet HIV/AIDS patients in their terminal stages when HIV/AIDS-related opportunistic infections are highly manifest; a situation exemplified by the recorded symptoms that were not specific or directly related to HIV/AIDS. There is a need to impart the appropriate knowledge in the identified deficient areas to avoid possibilities of further spread of the disease through the traditional medicine delivery system

Some pharmacological properties of extracts of Terminalia sericea roots.

Terminalia sericea Burch. Ex. DC (Combretaceae) extracts are used to treat bacterial infections, diarrhea, and diabetes. Intermediate and polar extracts of the roots exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus anthracis, and Pseudomonas aeruginosa, while the petroleum ether extract was inactive. The extracts were mildly active against Bacillus anthracis and Pseudomonas aeruginosa but exhibited the highest activity against Staphylococcus aureus. They also exhibited antifungal activity against Candida albicans and Aspergillus niger. An 80% aqueous ethanol extract of the roots did not have any effect on blood glucose levels during an oral glucose tolerance test (OGTT), in mice (P>0.05). With the exception of the dichloromethane and petroleum ether extracts, all the intermediate and polar extracts were toxic to brine shrimps giving LC(50) (95% confidence intervals) values ranging from 5.4 (3.5-8.4) to 17.4 (11.4-26.5) microg/ml, while that of cyclophosphamide, a standard anticancer drug, was 16.3 (10.6-25.2) microg/ml. Further work is in progress to isolate and identify active compounds in the extracts.

Evaluation of bioactive saponins and triterpenoidal aglycons for their binding properties on human endothelin ETA and angiotensin AT1 receptors.

Different types of triterpenes including saponins and aglycons were evaluated for their ability to inhibit [3H] BQ-123 and [3H] angiotensin II binding to the human endothelin 1 ETA and angiotensin II AT1 receptors, respectively. Selectivity for only one of the two receptors was exhibited by asiatic acid and its saponins (ETA) and oleanolic acid (AT1). To a lesser extent betulinic acid, beta-amyrin and friedelin also showed selectivity for the ETA receptor. To address the question whether the effect of saponins on cell membranes might interfere with the normal binding of specific radioligands to their receptors, the activity of saponins with different haemolytic properties were compared. Highly haemolytic saponins such as alpha-hederin and beta-escine showed partial (60%) inhibition of radioligand-binding to the ETA receptor and complete inhibition (100%) to the AT1 receptor. Moreover, the haemolytically inactive kryptoescine, at the same concentration, caused complete inhibiton of radioligand-binding to both receptors, indicating that inhibition of receptor binding was not related to the membrane-interacting properties of saponins.

Diterpenoids from the roots of Croton macrostachys.

Three novel diterpenoids have been isolated from the roots of Croton macrostachys. The structure and stereochemistry of the compounds have been unambiguously settled as neoclerodan-5,10-en-19,6beta;20,12-diolide, 3alpha, 19-dihydroxytrachylobane, and 3alpha,18,19-trihydroxytrachylobane from detailed spectroscopic evidence.

Some pharmacological properties of an aqueous extract of securinega virosa roots.

An aqueous extract of Securinega virosa is used by traditional healers in Tanga (northeastern Tanzania) as an aphrodisiac and in the treatment of impotence, which is one of the manifestations of diabetes mellitus. An aqueous extract of the roots at doses of 0.1,0.2, 0.4 and 1.0 g/kg body weight lowered the area under the oral glucose tolerance curve (OGTT) in normal albino rabbits by 0.3 (P >0.05), 7.85, 11.0 and 9.6% (P =0.05), respectively. Chlorpropamide (0.1 g/kg body weight) had a greater effect on blood glucose and lowered area under the OGTT curve by 16.3%. The extract, at a dose of 0.4 g/kg body weight, had no effect on fasting blood glucose (FBG) when compared to controls given distilled water (P >0.05), except at 4 h, when the FBG for treated animals was higher. The LD 50 (95% confidence interval) determined by intraperitoneal administration of the extract to white albino mice was 0.30 (0.20-0.50) g/kg body weight. We conclude that the aqueous extract of Securinega virosa roots lowered the area under the OGTT curve dose-dependently at doses between 0.1 and 1.0 g/kg body weight. It did not lower blood glucose below fasting levels both in the fed and fasted state. More work is required to determine the toxic characteristics of the extract and the utility of the observed activity in the management of diabetes mellitus in humans.

Evaluation of the antioxidant potential of natural products.

Since reactive oxygen radicals play an important role in carcinogenesis and other human disease states, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, test materials were assessed for potential to scavenge stable 1,2-diphenyl-2-picrylhydrazyl (DPPH) free radicals, reduce TPA-induced free radical formation in cultured HL-60 human leukemia cells, and inhibit responses observed with a xanthine/xanthine oxidase assay system. Approximately 700 plant extracts were evaluated, and 28 were found to be active in the DPPH free radical scavenging assay. Based on secondary analyses performed to assess inhibition of 7,12-dimethylbenz(a)anthracene-induced preneoplastic lesion formation with a mouse mammary organ culture model, Chorizanthe diffusa Benth. (Polygonaceae), Mezoneuron cucullatum Roxb. (Leguminosae), Cerbera manghas L. (Apocynaceae) and Daphniphyllum calycinum Benth. (Daphniphyllaceae) were selected and subjected to bioassay-guided fractionation. 5,7,3',5'-Tetrahydroxy-8,4'-dimethoxyflavonol, 5,8,4'-trihydroxy-7,3'-dimethoxyflavonol, 5,3',4'-trihydroxy-7-methoxyflavonol, and 6,3',4'-trihydroxy-7-methoxyflavonol were identified as active principles from C. diffusa. Piceatannol, trans-resveratrol, apigenin and scirpusin A were found as the active principles of M. cucullatum, olivil, (-)-carinol, and (+)-cycloolivil were active principles from C. manghas, and 5,6,7,4'-tetrahydroxyflavone 3-O-rutinoside and kaempferol 3-O-neohesperidoside were active principles from D. calycinum. Of these substances, the hydroxystilbenes piceatannol and transresveratrol have thus far been shown to inhibit carcinogen-induced preneoplastic lesion formation in the mouse mammary gland organ culture model.

Constituents from the stem wood of Euphorbia quinquecostata with phorbol dibutyrate receptor-binding inhibitory activity.

Bioassay-guided fractionation of an EtOAc extract of the stem wood of Euphorbia quinquecostata using a phorbol dibutyrate receptor-binding assay system as a monitor yielded four inhibitory isolates (1-4), inclusive of one new compound, 17-hydroxyingenol 20-hexadecanoate (1), and three previously known compounds, ingenol 20-hexadecanoate (2), ent-16 alpha,17-dihydroxyatisan-3-one (3), and ent-3 beta,16 alpha,17-trihydroxyatisane (4). Also isolated from this extract were 10 constituents inactive in this bioassay, namely, 2,2'-dihydroxy-4,6-dimethoxy-3-methylacetophenone (5), a new structure, and nine known compounds identified as ent-13S-hydroxyatis-16-ene-3, 14-dione; 2-hydroxy-4,6-dimethoxyacetophenone (xanthoxylin); 2-hydroxy-4,6-dimethoxy-3-methylacetophenone; 6-hydroxy-7-methoxycoumarin; lupeol acetate; beta-sitosterol; sitosterol beta-D-glucopyranoside; 6,7,8-trimethoxycoumarin; and 3,3',4'-tri-O-methyl-4-O-[alpha-L-rhamnopyranosyl (1"'-->6")-beta-D-glucopyranosyl]ellagic acid. The structures of compounds 1 and 5 were established by chemical and spectroscopic methods.