University of Dar es Salaam, Dar es Salaam, Tanzania
Research Area 1 : Natural Products Research
Natural Products Research: Study of Medicinal Plants
It is estimated that Tanzania's rain forests have more than 10,000 vascular plant species. Many of them are endemic in Tanzania and have not undergone extensive scientific study for their pharmacological and chemical constituents. Tanzania is a country of a wide topographical diversity, ranging in elevation from sea level to about 20,000 feet, the height of Mount Kilimanjaro. To a large extent, the country’s extensive variety of flora is attributed to this topographical diversity.
Training Protocol in the Study of Medicinal Plants
The training that is provided through MHIRT is a ten-week experience that combines field work, laboratory work, research discussions, research reports, and scientific presentations. A typical experience in Tanzania involves students working in research groups, which normally consist of M.S. and Ph.D. students and a faculty supervisor. The department of chemistry has a close working relationship with the departments of botany and microbiology. Therefore, the student also gets the benefits of interdisciplinary collaboration and training in plant taxonomy and bioassay. Students investigate plant materials that are collected from the field based on the following criteria:
- The plant is used in herbal remedies
- The plant belongs to a family or genus which is known to contain members with known biologically active constituents
- The plant has special characteristics as observed during field expeditions, e.g. is eaten by primates, does not have insect or fungal attacks, etc.
Students are taken to field trips where they receive exposure and training in plant collection techniques and to collect plant materials. The field trips also give the students an opportunity to see the countryside outside of the City of Dar es Salaam.
Crude material isolated
from plant specimens
The students' research typically involves a plant part: root, stem bark, or seeds, which they carry through an established protocol to isolate chemical compounds. Students learn a variety of techniques and protocols commonly used in natural products laboratory work, such as the processing of natural product materials for experimentation, separation of crude materials, isolation of compounds from crude materials, chromatographic separations, spectroscopic characterization of isolated compounds, and basic tests for bioactivity. Spectroscopic characterization of isolated compounds allows students to develop skills in NMR and mass spectrometry methods. They learn how to interpret the information obtained by comparing the structure suggested by NMR spectrum and a corresponding mass spectrum with information from the chemical literature. While the actual structure of the compound may not be solved by this exercise, students develop valuable skills in trying to obtain chemical information of the isolated materials.
The summer experience culminates in the presentation of the research in a symposium and submission of a full research report to the project director upon returning to the States. Many of the students have also presented their work in a variety of professional meetings and symposia in the States.
Natural products research incorporating training in Traditional Medicine
Traditional Medicine is practiced in many developing countries, including Tanzania, where plant products in their crude forms or as partially processed remedies are directly administered to patients. Traditional medicines can be loosely described as the combination of knowledge and practice used in diagnosing, preventing, or eliminating a physical, mental, or social imbalance, that is based on the socio-cultural and religious backgrounds. In Africa, the practice usually relies on past experience and observations handed down from one generation to the next. The medical practice is a reflection of the African culture and it may not necessarily be based on any recognized scientific framework, but rather it is influenced by the accumulated experience of what was proved effective by ancestors. Rural communities in most developing countries have practiced herbal remedies for centuries, and therefore the effectiveness and safety of these crude remedies have already been established through long experiences.
The Traditional Medicine training component is done in collaboration with and under the guidance of scientists in the Institute of Traditional Medicine at the Muhimbili College of Health Sciences. In addition to field trips to collect specimens and learn plant taxonomy, excursions are organized that focus specifically on a systematic information collection as it relates to the social, ecological, and cultural aspects of the materials used in the research.
About the Institutes of Traditional Medicine
The Institute of Traditional Medicine is charged with the responsibility to research into traditional healing systems, in Tanzania, to identify useful practices which can be adopted and to also identify useful materials that can be modernized and developed into drugs. Tanzania is estimated to have a traditional healer/population ratio of 1:400, thus giving an estimated number of over 80,000 traditional healers with varying specialities. The majority of healers are herbalists using mainly plants and a few animal and mineral products. There are also practices such as bone setting and socio-cultural aspects which contribute to the healing practices. The Institute aspires to play a leading role in the development of Tanzania's vast resource of natural products by strategically building expertise in all areas related to drug development, including basic science knowledge base; biological testing; pre-clinical toxicological studies; clinical trials and evaluation; pharmaceutical technology; standardization of herbal pharmaceuticals; biotechnology aimed at producing plants with best levels of active molecules and maturing in a short period of time; and tissue culture for production of secondary metabolites as drugs.
The research training at the Institute of Traditional Medicine focuses on three areas: ethnobotanical, anthropological, chemical and biological studies. Below are brief descriptions of research activities that are currently under way.
Therapies to treat HIV/AIDS: The Institute has an extensive program to evaluate therapies that are being used by traditional healers to treat HIV/AIDS patients. In this program patients are being monitored for clinical progression of the disease. This is coupled with laboratory monitoring of immunological indicators (CD4, CD8 counts), hematological parameters (FBP), liver function test (ASAT, ALAT) and kidney function test (Serum creatinine). Concurrently the Institute is running a program to evaluate extracts from different plants for antiviral, anticancer, anti-bacterial and anti-fungal activity. The Institute recently acquired three human cancer cell lines that are going to be used for cytotoxicity testing. The aim is to expand the range of available cell lines to be able to also culture different viruses.
Search for plant derived compounds for treatment of type 2 diabetes mellitus: Both ethnomedical and laboratory studies on plants used traditionally for treatment of type 2 diabetes mellitus are being done by the Institute. Diabetes research still remains to be one of the core research areas.
Discovery of antimalaria compounds from marine invertebrates and terrestrial plants: This is a collaborative project being done jointly between the Institute of Traditional Medicine, the Institute of Marine Sciences in Zanzibar, and the Department of Parasitology of the School of Public Health and Social Sciences. It is a WHO funded project. The aim is to expand this project to a large program to search for novel antimalarial compounds from the large pool of endemic plants in Tanzania. Already members of staff are undergoing training in invivo and invitro testing methods.
Search for anticonvulsants from Tanzanian plants: This is a low key activity of the Institute. It is not one of the major priority areas but a number of students do projects in this area. Testing for anticonvulsant activity, using the picrotoxin, pentylenetetrazol and strychnine models, is well established at the Institute.
Formulation and standardization of herbal medicines: The Institute has in place an herbal standardization unit, which was recently established. The intention is to promote the use of herbal medicines from plants whose therapeutic value is already established. Partnership with pharmaceutical industry is being sought to facilitate commercialization of the production of herbal medicines.
Ethnobotanicals:This is an ongoing activity to continue identifying plants that are being used by traditional healers for the treatment of various diseases.
Training protocol in Traditional Medicine
The trainees engage in a week-long field trip during which they visit selected traditional healer facilities. These visits provide trainees an exposure to how traditional healing is practiced. They also gather information on the type of herbs being used for the treatments, and the methods of application. Samples of the herbs are collected from the forest with the help of a botanist and taxonomist from the University of Dar es Salaam. The collected materials are then authenticated at the University herbarium. The plant materials are analyzed for their chemical constituents using chromatographic and spectroscopic techniques.
Research Area 2 : Environmental Health
Source Water Studies
Communal source water in Vikuge Village, outside Dar es Salaam
The environmental health component has been carefully designed, using water quality as the central theme, to emphasize the direct link between human activity, such as agriculture, and environmental quality. The trainees develop environmental case studies; they learn how to connect empirical scientific data to human health conditions; and they collect data that is shared with others involved in epidemiological and clinical investigations. Students also learn the use of a variety of state-of-the-art analytical techniques.
The use of pesticides and other agricultural chemicals, and heavy metals, such as mercury whose use in small-scale mining has been on the rise in recent years, pose a serious threat to water quality and public health. In Tanzania, excessive amounts of pesticides have been imported, and in the absence of proper disposal facilities, has led to improperly stored pesticide materials, contaminating surrounding soil, water, and air. Published reports have linked these materials to possible serious endocrine damage, so-called "endocrine disrupters" which are chemicals, including commonly used pesticides, that appear to mimic hormone molecules, thereby imparting serious adverse effects on the endocrine system, at least of lower animals. While many of these materials have been banned in Europe and the United States, they are still very accessible in developing countries.
The University of Dar es Salaam has initiated a research program to monitor environmental pollution in city grown foodstuffs and in agricultural zones in Tanzania in general, through analyses of foodstuffs, fishes, drinking and ground water, soils, etc. Since health hazards caused by pesticide residues are well documented, it is expected that the results from these studies will allow an interpolation on the extent to which the pesticides affect human health.
Training protocol in Source Water Studies
The training involves monitoring of the extent of pollution by chemical pesticides through analysis of pesticide residues in drinking water and some foodstuffs in Dar es Salaam and Coast Regions. The residues analyzed are those belonging to pesticides that have already been identified to be of greatest environmental concern in the region.
- Organochlorines -Aldrin, DDT, dieldrin, endosulfan, HCH and heptachlor
- Organophosphates -Parathion, metamidophos, monocrtophos, dimethoate, malathion
- Carbamates -Aldicarb, methomyl and carbaryl
- Pyrethroids -Cyhalothrin, cypermethrin
- Others -Methyl bromide, amitraz
In addition to developing new environmental health research skills, the participating students develop an appreciation for the exposure and conditions that people in developing countries are subjected to as these countries strive to improve their food and economic capacities. Participants visit agricultural and industrial sites and water sources, and characterize the areas with respect to human activity and the interplay between that and the water system. By conducting case studies surrounding water quality, important data are generated that will be useful in future toxicological and epidemiological investigations. A case study that has been initiated looks at the impact of environmental pollutants on water quality and human health. The aim is to determine possible linkages between pesticide use practices and prevailing community health problems, including cancers.
Biochemical Engineering in Environmental Health Studies: Food industry wastewater treatment
Industrial discharge outside Dar es Salaam
In recent years, food preservation programs and processes have increased significantly, a development that is surely critical for the welfare of the people. This has been particularly pronounced in fruit processing, cereal processing, dairy and meat products, and in the improvement of cane sugar processing and corn/cereal processing industry. This growth, however, is accompanied by the increase in wastewater volumes entering surface and ground water systems.
Because of the water pollution threat posed to the receiving water masses, a need arises to treat such wastewater effectively to preserve our environment. This research is aimed at providing solutions in the food-industry wastewater treatment. Previous research at the Chemical and Process Engineering Department utilized biological treatment technology using a three-phase fluidized bed bioreactor (TPFBB) in the treatment of industry wastewater from brewery and refinery industries. Preliminary results of the study point to possible application of this technology in the treatment of food industry wastewater.
Initially, the performance characteristics of the TPFBB were studied using only one type of biomass support particles (i.e. the KMT® support). There is a need to study its performance under different conditions. Because most types of food-industry wastewater are treatable using biological and chemical means, this research is aimed at re-commissioning the reactor and studying the performance of the TPFBB under the following conditions: using three different support solids (sand, charcoal and KMT®); to establish suitable chemical methods for food-industry wastewater treatment prior to biological treatment (chemical conditioning); and to examine the performance of TPFBB in treatment of wastewater from food industry.
Training protocol in wastewater treatment research
This research comprises modifications and re-commissioning of the existing TPFBB, collection and testing of wastewater samples, and treatment of food-industry wastewater using different biomass support, including chemical and biological materials. The treatment efficiencies will be compared based on different conditions. Cost analysis will be conducted based on capital costs, especially the cost of chemicals and power consumption.