Brine shrimp toxicity of some plants used as traditional medicines in Kagera Region, north western Tanzania.

Dichloromethane and/or ethanol extracts of 30 plants used as traditional medicines in Bukoba district, northwestern Tanzania were evaluated for brine shrimp toxicity. Among the 50 extracts tested, 32 extracts (64%) showed very low toxicity with LC50 values above 100 microg/ml. Among these 12 (24%) which had LC50 >500 microg/ml can be categorized as being practically non-toxic. Among the remaining extracts 19 (38%) which showed LC50 > 100 < 500 microg/ml are also considered to be non-toxic. Extracts that showed LC50 results between 30-100 microg/ml have been categorized as mildly toxic; these include ethanol extracts of Lantana trifolia (LC50 32.3 microg/ml), Vernonia bradycalyx (LC50 33.9 microg/ml), Antiaris toxicaria (LC50 38.2 microg/ml) and Rubus rigidus (LC50 41.7 microg/ml) and the dichloromethane extracts of Gynura scandens (LC50 36.5 microg/ml) and Bridelia micrantha (LC50 32.0 microg/ml). The dichloromethane extracts of Picralima nitida (LC50 18.3 microg/ml) and Rubus rigidus (LC50 19.8 microg/ml), were only moderately toxic. Picralima nitida and Rubus rigidus extracts are only 1.1 and 1.2 less toxic than the standard drug, cyclophosphamide (LC50 16.3 microg/ml). In conclusion, the results indicate that among the 30 plants used as traditional medicines, 28 are safe for short term use. Picralima nitida and Rubus rigidus extracts are mildly toxic, but by comparison have a remote possibility to yield active anticancer compounds.

Antimicrobial and brine shrimp toxicity of some plants used in traditional medicine in Bukoba District, north-western Tanzania.

Herbal medicines constitute a potentially important resource for new and safe drugs for the management of microbial infections and other diseases. In this study, dichloromethane, ethylacetate and ethanol extracts of Canarium schweinfurthii Engl., Dissotis brazzae Cong., Iboza urticifolia (Bak) E.A.Bruce, Isoglosa lacteal Lindau, Strombosia Scheffleri Engl., and Whitfieldia elongate T. Anders were tested for antimicrobial activity and brine shrimp toxicity. The objective was to validate claims that they are used to treat bacterial infections, diarrhoea and heal wounds among the Haya tribe of north-western Tanzania. At least one extract of each plant showed antibacterial activity. Dichloromethane extracts were the most active while ethanol extracts were the least active. Extracts of Whitfieldia elongate and Isoglossa lacteal were the most and least active with MICs in the range 0.08-0.62 mg/ml and 15.6-62.5 mg/ml, respectively. The dichloromethane extract of Whitfieldia elongate exhibited strong antifungal activity against Cryptococcus neoformans. Against brine shrimp larvae, the extracts from the six plants exhibited a low to very low toxicity with LC50 values ranging from 15.35-374.0 microg/ml. However, ethanol extracts of Dissotis brazzae and Strombosia scheffleri had LC50 values of >1000 microg/ml. The seemingly innocuous nature and relatively good antibacterial activity against skin infections and gastrointestinal pathogenic bacteria support the traditional uses of the plants and deserve more detailed studies.

Isolation of a stilbene glycoside and other constituents of Terminalia sericeae.

The ethanol extract of the root bark of Terminalia sericea yielded an unreported stilbene glycoside, 3'5'-dihydroxy-4-(2-hydroxy-ethoxy) resveratrol-3-O-beta-rutinoside (1) together with known compounds resveratrol-3-beta-rutinoside glycoside (2), 3',4,5'-Trihydroxystilbene (resveratrol) (3), triterpenoic acid arjungenin and a mixture of beta-sitosterol and stigmasterol. Structure determination of the isolated compounds was achieved on the basis of spectroscopic measurements.

Anticonvulsant Activity of Extracts of Epilepsy Fscheri Stem Bark

Evaluation of extracts of Diospyros fischeri Gurke (Ebenaceae); which is used traditionally for the treatment of epilepsy shows that the aqueous extract of the tem bark has no effect against picrotoxin induced convulsions in mice. However; an 80ethanol extract of the bark caused dose-dependent suppression of convulsions induced by 10 mg/kg body wt picrotoxin; at doses between 100-3200 mg/kg body wt. Petroleum ether; 1:1 dichloromethane:methanol; and methanol extracts also suppressed picrotoxin-induced convulsions; but had a slightly lower inhibitory effect. The petroleum ether extract was the most active; but all were less active than the ethanol extract. Unlike phenobarbitone; which at 50 mg/kg body wt completely suppressed convulsions induced by 10 mg/kg body wt picrotoxin; none of the plant extracts completely suppressed convulsions in the mice. These results support the traditional uses of D.fischeri for the treatment of epilepsy. Given the seemingly innocuous nature of the extracts more work is suggested to ascertain their clinical application

Medicinal plants used by Tanzanian traditional healers in the management of Candida infections.

An ethnomedical survey in Coast, Dar es Salaam, Morogoro and Tanga regions of Tanzania has resulted in the identification of 36 plant species belonging to 21 plant families that are used traditionally for the treatment of Candida infections. Twenty-one plants constituting 58.3% of all collected plants are used to treat of oral candidiasis (Utando) one of the important signs of HIV/AIDS. The knowledge of traditional healers for the treatment of Candida infections has been highly supported by the literature in that 13 (36.1%) out of the 36 plants identified have been proven to be active against Candida albicans and/or other species of Candida. Also, some of the plants were reported to be active against other species of fungi including Cryptococcus neoformans, one of the important pathogenic fungi in HIV/AIDS. It can be seen that ethnomedical information from traditional healers provides a solid lead towards development of new drugs than random screening. The task that remains is to screen extracts prepared from these plants and perform a bioassay-guided fractionation of the active extracts so as to isolate the active compounds from these plants.

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.

Current and future prospects of integrating traditional and alternative medicine in the management of diseases in Tanzania.

Traditional medicine and medicinal plants, in general, continue to be a powerful source of new drugs, now contributing about 90% of the newly discovered pharmaceuticals. Traditional medicine continues to provide health coverage for over 80% of the world population, especially in the developing world. The past and the present are all full of living examples of discoveries of drugs, ranging from anticancer, antiasthma, antidiabetic, antihypertensives and many others which owe their origin to traditional medicine. The current era of HIV/AIDS is not short of contributions from traditional medicine. The recent discovery of the non-nucleoside reverse transcriptase inhibitor (NNRTI), calanolide A, is a new addition from traditional medicine. Many more such discoveries are yet to come. While this potential is much acknowledged, little has been done in African countries, to utilize the plants that are already known and proven to be safe for use by patients. A number of plants could be widely cultivated for local industrial production of medicines and herbal nutritional supplements. There is need to ensure that what is known is made use of, for financial gain, and for improvement of the health of our people. We need to establish the necessary expertise for development of traditional medicines and deliberate efforts should be made to encourage local industrial production of traditional/herbal medicines so that cultivation may become possible and hence contribute to poverty reduction.

Evaluation of the quality of amodiaquine and sulphadoxine/pyrimethamine tablets sold by private wholesale pharmacies in Dar Es Salaam Tanzania.

OBJECTIVE: There are several independent reports in Tanzania of treatment failures with commercially available sulphadoxine/pyrimethamine (SP) and amodiaquine (AQ) brands. The aim of this work was to assess the quality of SP and AQ tablets marketed by wholesale pharmacies in Dar Es Salaam, Tanzania. METHODS: All eight wholesale pharmacies authorized to import medicines and located in Dar Es Salaam were included in the study. From each pharmacy, samples of all SP and AQ brands available at the time of sampling were bought, provided they had a shelf-life of at least 1 year. A sample was either an intact box of 100 tablets or a sealed tin of 100 tablets. To ensure blinding, 30 tablets of each sample were removed from their original containers, coded and sent to the quality control laboratory for analysis. The name, strength, batch number, manufacturer and the expiry dates of the tablets were recorded. In total 15 AQ and 18 SP samples were collected. Identity, assay for content of active ingredients and dissolution assay were performed as described in the United States Pharmacopoeia (USP). RESULTS: All samples passed the identity test. Among the AQ samples collected, two of 15 (13%) failed the dissolution test but all passed the assay for content, whereas two of 18 (11%) and eight of 18 (44%) SP samples failed the assay for content and dissolution tests, respectively. None of the pharmacies stocked all AQ and SP brands. CONCLUSION: This work reveals the availability of poor quality antimalarial drugs on the Tanzanian market. Use of substandard drugs could have serious clinical consequences to patients. The results support the need for continuous monitoring of the quality of marketed drugs to ensure safety and efficacy of these products in the treatment of malaria in endemic areas.

Comparative bioavailability of oral sugar-coated and plain formulation of chloroquine phosphate marketed in Tanzania.

The bioavailability of chloroquine from a single oral dose (10 mg/kg body weight) of a sugar-coated (Dawaquin) and a plain formulation (Shellyquine) of chloroquine phosphate were compared in two groups of 10 volunteers each, following an overnight fast. Whole blood chloroquine concentrations were measured using high-performance liquid chromatography (HPLC) and bioavailability was determined by measuring area under the blood chloroquine concentration curve (AUC ng mL(-1) h) and the peak blood chloroquine concentration (Cpmax ng/mL). The AUC and Cpmax for Shellyquine were 4396.3 +/- 833 ng mL(-1) h and 162 +/- 14 ng/mL, respectively. The AUC and Cpmax for Dawaquin were 2060 +/- 339 ng mL(-1) h and 56.6 +/- 5.2 ng/mL, respectively. Shellyquine was significantly more bioavailable than Dawaquin (P<0.001). Although the Cpmax for Dawaquin was higher than the required therapeutic level for sensitive Plasmodium falciparum of 30 ng/mL, its blood levels may not guarantee a rapid clearance of parasites. The differences between the two formulations point to a problem in the quality of pharmaceuticals marketed in this country, whose extent need to be ascertained further. Failure of chloroquine phosphate in this country has already been declared by the Ministry of Health, and the potential contribution of poorly formulated products remains a subject of debate.

The effect of Phyllanthus amarus aqueous extract on blood glucose in non-insulin dependent diabetic patients.

The glycaemic response to 124.5 +/- 9.3 (mean +/- SD) g of pancakes was monitored in 21 non-insulin dependent diabetic (NIDDM) patients while on oral hypoglycaemics, after a 1-week washout period and after a 1-week twice daily treatment with 100 mL of an aqueous extract from 12.5 g of powdered aerial parts of Phyllanthus amarus. After the 1-week washout period, the fasting blood glucose (FBG) and postprandial blood glucose increased significantly compared with treatment on oral hypoglycaemics ( p < 0.05). After a 1-week herbal treatment no hypoglycaemic activity was observed. Both FBG and postprandial blood glucose remained very similar to that recorded after the washout period ( p > 0.05). Both liver and renal functions based on alanine transaminase (ALAT) and serum creatinine, respectively, were not significantly affected by the use of the extract. Although the lymphocyte and monocyte levels were significantly decreased ( p < 0.05) and the granulocyte level was significantly increased after treatment ( p < 0.05) the overall total white blood cell (WBC) count and haemoglobin (Hb) were not significantly affected by the 1 week herbal treatment. We conclude that 1 week treatment with the aqueous extract of Phyllanthus amarus was incapable of lowering both FBG and postprandial blood glucose in untreated NIDDM patients.

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.

Effect of caesalpina bonducella seeds on blood glucose in rabbits.

The seeds of Caesalpinia bonducella (L.) Flem. (Caesalpiniaceae) are sold in shops in Dar es Salaam, Tanzania, for the treatment of diabetes mellitus. A suspension of the powdered seed kernel in 0.5% carboxymethylcellulose (CMC) was tested for ability to lower blood glucose in fasted and glucose-fed normal albino rabbits. Following administration of 0.2, 0.4 and 0.8 g/kg body weight of the powder there was no difference in areas under the fasting blood glucose and oral glucose tolerance test (OGTT) curves as compared to controls given CMC (P > 0.05). Similarly, 0.2 g/kg body weight of the powder administered for 7 consecutive days had no effect on either fasting blood glucose or the clearance of a glucose load from the blood. However, 0.1 g/kg body weight chlorpropamide significantly decreased the area under the fasting blood glucose and OGTT curves as compared to controls given CMC (P = 0.05). Thus, contrary to a previous report, we could not detect any hypoglycaemic activity in the seeds of Caesalpinia bonducella growing in Dar es Salaam.

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.