Toxicological Survey of African Medicinal Plants

Victor Kuete

• Publisher: Elsevier
• Year: 2014
• ISBN:
  9780128004753
• Topic: Medicine
• Subtopic: Toxicology

Toxicological Survey of African Medicinal Plants provides a detailed overview of toxicological studies relating to traditionally used medicinal plants in Africa, with special emphasis on the methodologies and tools used for data collection and interpretation. The book considers the physical parameters of these plants and their effect upon various areas of the body and human health, including chapters dedicated to genotoxicity, hepatotoxicity, nephrotoxicity, cardiotoxicity, neurotoxicity, and specific organs and systems.Following this discussion of the effects of medicinal plants is a critical review of the guidelines and methods in use for toxicological research as well as the state of toxicology studies in Africa. With up-to-date research provided by a team of experts, Toxicological Survey of African Medicinal Plants is an invaluable resource for researchers and students involved in pharmacology, toxicology, phytochemistry, medicine, pharmacognosy, and pharmaceutical biology.

• Offers a critical review of the methods used in toxicological survey of medicinal plants
• Provides up-to-date toxicological data on African medicinal plants and families
• Serves as a resource tool for students and scientists in the various areas of toxicology

1

Toxicological Societies in Africa

Roles and Impact in Policy Making and Living Conditions

Jules C.N. Assob¹, Dickson S. Nsagha¹, Neville Mvo Ngum¹ and Victor Kuete², ¹Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Cameroon, ²Department of Biochemistry, Faculty of Science, University of Dschang, Cameroon

Human exposure to persistent toxic substances including both toxic metals and persistent organic pollutants can be from either natural sources, current or past industrial activities, or anthropogenic activities. The continuous consumption of unsafe food following pesticide and chemical exposure remains a major global public health challenge, especially in Africa where there is very little awareness of the toxicological profiles of most chemicals. Though many African countries are setting up policies on the use of toxic chemicals, the actual implementation of these policies is weak and many toxicological societies and nongovernmental organizations have been formed to help the governments in this endeavor. Hence, scientists in academia, research, industry, and governmental organizations are coming together to form the necessary toxicological societies to this effect. The first part of this chapter discusses the existing toxicological societies in Africa with highlights of their goals, mission, objectives, and activities, as well as a review on their collaborations and interactions with other international toxicological organizations. The second part will review the role of these African toxicological societies in government policy making.

Keywords

Persistent toxic substances; anthropogenic activities; nongovernmental organizations; toxicology; Africa

1.1 Introduction

Africa and other developing countries are experiencing a rise in both informal mining especially artisanal gold mining and other fluctuating informal industrial activities that are often situated within communities and surrounded by the mainstream population. This, together with the increasing population migration and rapid urbanization that encompasses a wide range of anthropogenic activities, contribute to environmental degradation and pollution. The high prevalence of infectious diseases such as lung diseases, tuberculosis, human immunodeficiency virus/acquired immunodeficiency syndrome coupled with the malaria endemicity make the populations of Africa and other developing countries more susceptible to the toxic effects of pollutants [1].

Human exposure to persistent toxic substances (PTS) including both toxic metals exposure and persistent organic pollutants (POPs) exposure can be from either natural sources, current industrial activities, past industrial activities, or anthropogenic activities. PTS have the ability to exert negative health effects that are often subtle, long term, sometimes transgenerational, and difficult to measure, even in large epidemiological studies. Furthermore, the continuous consumption of unsafe food following pesticide and chemical exposure remains a major global public health challenge, especially in Africa, where there is heavy application of a variety of chemicals yet so little available toxicological data on the chemicals [2].

Although necessary measures have been taken by developed countries to curb both the exposure and the effects to toxic substances, developing countries in general and African countries in particular still lag behind [2]. Generally, the various governments in Africa have enacted policies and institutions with regard to the use and control of chemicals with potential hazards to humans. However, most of these governmental policies and institutions are weak and should be accompanied in their endeavors by nonprofit nongovernmental organizations (NGOs) that can gather experts in academia, research institutions, government, and multinational societies to reinforce strategies necessary to curb human and environmental toxicity. To this effect, Africa has witnessed the formation of many organizations at the continental, regional, and national levels such as the African Society for Toxicological Sciences (ASTS), Society of Environmental Toxicology and Chemistry (SETAC)-Africa, West African Society of Toxicology (WASOT), Cameroon Society for Toxicological Sciences (CSTS), Association Tunisienne de Toxicologie (ATT), and the Egyptian Society of Toxicology (EST). This chapter aims to highlight the role of these NGOs and other major projects in creating awareness of the existing and potential toxicological hazards for populations and the ecosystems on the African continent and how their available data on specialized knowledge can be used to liaise with governments, industries, and other NGOs. The missions, goals, histories, and achievements of the various organizations are presented in this chapter and the mentoring role of worldwide organizations such as the International Union of Toxicology (IUTOX) and Society of Toxicology (SOT) in accompanying African experts in developing new skills through trainings and traveling grants have been acknowledged.

1.2 Toxicological Societies in Africa

1.2.1 African Society for Toxicological Sciences

The ASTS is a not-for-profit organization of scientists in academia, industry, and governmental organizations from around the world. Members of ASTS include scientists and policy makers who are interested in health and environmental issues that affect the continent of Africa. ASTS seeks to promote the acquisition and utilization of knowledge in toxicological sciences relevant to the continent of Africa [3].

1.2.1.1 Mission

The organization’s mission is to create awareness of existing and potential toxicological issues that constitute hazards for the populations and ecosystems on the African continent. The Society strives to promote human health and a safe environment through research and education. Members are available to share their specialized knowledge with government, industry, and NGOs.

1.2.1.2 Goals

The goals of the organization are (i) to promote the development of relevant curricula in toxicological sciences among institutions of higher learning in Africa; (ii) to create awareness of African toxicological issues in scientific and medical circles worldwide; (iii) to provide expertise in medical, veterinary, and environmental toxicology to African governments, organizations, institutions of higher learning, and the international community on issues of toxicology relevant to Africa; (iv) to encourage and foster self-sustaining partnerships between the pharmaceutical and chemical industries and government, private, and NGO sectors in Africa that promote the safety and health of Africans and their resources; (v) to act as a liaison with other toxicological and scientific organizations worldwide on behalf of the African continent; and (vi) to create public awareness of activities that might lead to toxicological problems or health hazards on the continent of Africa [3].

1.2.1.3 History and Achievements of ASTS

Twenty African scientists attending the SOT meeting in Seattle, WA, in 1998 found it necessary to form ASTS, which was later founded in March 1999 in New Orleans, LA. It organized its first workshop in Accra, Ghana, in January 2001 followed by a satellite meeting of ASTS members and advisors in Salt Lake City, UT, to discuss achievements and the future direction of the association. The Third International ASTS Conference was held in Abuja Nigeria on April 22–27, 2003; the main sponsor was the National Institute for Environmental Health Sciences (NIEHS). In 2004, an ASTS mini-symposium was held in Baltimore, MD, on the theme: “Sustainable development and the management of industrial chemicals and pharmaceuticals in Africa.” The Director General, Dora N. Akunyili, PhD of the National Agency for Food and Drug Administration and Control, Nigeria, was the keynote speaker [3].

In 2005, a conference was held at the Hilton Riverside Hotel, New Orleans, LA, on the theme: “Emerging health and environmental adverse effects of pharmaceuticals and industrial chemicals and the need for good regulatory policy in Africa.” The keynote speaker was John O’Donoghue, DVM, PhD, DABT, former Director of Health and Environmental Laboratories of Eastman Kodak Co. Representatives for SETAC and SOT participated, and travel awards to three African scientists to attend the SOT annual meeting were awarded. The awardees were Prof. Isaac U. Asuzu of the Department of Veterinary Physiology & Pharmacology, University of Nigeria Nsukka, Enugu State, Nigeria, who presented a paper titled “Alternative treatment of snakebites from plant-extracts used in folklore medicinal practices in Nigeria”; Dr. Orish E. Orisakwe of the Department of Pharmacology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi, Nigeria, who presented a poster titled “Heavy metal exposure from herbal supplements in Nigeria”; and Dr. Balarabe Magaji Jahun of the Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Ahmadu Bello University Zaria Nigeria, who presented a poster titled “Efficacy of piroxicam in alleviating tetracycline-induced muscle damage.”

In 2006, a conference took place at Marriot Hotel & Marina, San Diego, CA, on “The millennium development goals and the role of toxicologists and environmental health scientists.” The keynote speaker was Dr. Gerald Fisher, senior vice president, Wyeth, who presented on “Moxidectin safety and efficacy studies for the elimination of river blindness in Africa, a WHO/Wyeth collaboration.” Two travel grants were awarded to attend the SOT meeting in San Diego, CA: to Eric Banseka Tungla of the Department of Biochemistry, University of Yaounde I, Cameroon, who presented a poster entitled “Toxicity risk assessment of Carica papaya leaves aqueous extract in albino rats (Rattus norvegicus),” and to Mamadou Fall of the Laboratory of Toxicology and Hydrology, Faculty of Medicine, University of Dakar, Dakar, Senegal, who presented a poster titled “Mutagenicity of benzyl chloride in the AMES test depends on exposure conditions.”

An International Conference on “Risk Assessment and Quality Assurance Training” and a workshop was later held on October 21–28, 2006 in Limbe, Cameroon, chaired by Dr. Ken Olden and was attended by 47 participants from Cameroon, Nigeria, Sudan, South Africa, the United States, the United Kingdom, Italy, and Belgium. This conference led to the formation of the CSTS. Several organizations including IUTOX, NIEHS, British Society of Toxicology, and Wyeth, sponsored and participated in the workshop.

In 2007, a conference was held in Charlotte, NC, on the theme: “Working together to promote hazard identification and influence environmental policies and regulations in Africa,” which spearheaded the formation of the Toxicologists of African Origin Special Interest Group with SOT and promoted collaboration with the National Library of Medicine on the World Library Project.

In 2008, an informational session at the SOT conference titled “Toxicological and public health challenges in Africa.” Three travel grants were awarded to Lyndy McGaw from South Africa, Gerard Ngueta from Belgium, and Evans Afriyie-Gyawu from Texas A&M University, to attend the SOT meeting in Seattle, WA. In its 10 years of existence, ASTS has sponsored eight scientists to attend SOT meetings in the United States at a cost of more than $20,000. This cost is in addition to those invested in organizing conferences in Africa and the United States [3].

1.2.2 Society of Environmental Toxicology and Chemistry

SETAC Africa is a geographic unit of the SETAC established to promote and undertake activities of SETAC in the Africa region [4]. The SETAC world council approved full geographic unit status for Africa in May 2012 at the sixth SETAC world congress. The decision came after a decade of SETAC activity in Africa, including the formation of an SETAC Africa branch within SETAC Europe and a series of biannual meetings, most recently in Buea, Cameroon, in May 2011, and prior to that in Kampala, Uganda (2009), Arusha, Tanzania (2007), and in South Africa [4].

1.2.2.1 Goals of SETAC Africa

SETAC is designed (i) to promote research, education, training, and development of the environmental sciences, specifically environmental toxicology and chemistry, hazard assessment, and risk analysis; (ii) to encourage interactions among environmental scientists and dis...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• List of Contributors
• 1. Toxicological Societies in Africa: Roles and Impact in Policy Making and Living Conditions
• 2. Ethical Issues for Animal Use in Toxicological Research in Africa
• 3. Critical Review of the Guidelines and Methods in Toxicological Research in Africa
• 4. Discordant Results in Plant Toxicity Studies in Africa: Attempt of Standardization
• 5. Acute and Subacute Toxicities of African Medicinal Plants
• 6. Subchronic and Chronic Toxicities of African Medicinal Plants
• 7. Toxic Plants Used in African Traditional Medicine
• 8. Cytotoxicity of African Medicinal Plants Against Normal Animal and Human Cells
• 9. Genotoxicity and Teratogenicity of African Medicinal Plants
• 10. Mutagenicity and Carcinogenicity of African Medicinal Plants
• 11. Hepatotoxicity and Hepatoprotective Effects of African Medicinal Plants
• 12. Nephrotoxicity and Nephroprotective Potential of African Medicinal Plants
• 13. Cardiotoxicity and Cardioprotective Effects of African Medicinal Plants
• 14. Neurotoxicity and Neuroprotective Effects of African Medicinal Plants
• 15. Toxicity and Beneficial Effects of Some African Plants on the Reproductive System
• 16. African Plants with Dermatological and Ocular Relevance
• 17. Toxicity and Protective Effects of African Medicinal Plants on the Spleen and Lung
• 18. Safe African Medicinal Plants for Clinical Studies
• 19. Harmful and Protective Effects of Terpenoids from African Medicinal Plants
• 20. Harmful and Protective Effects of Phenolic Compounds from African Medicinal Plants
• 21. Health Effects of Alkaloids from African Medicinal Plants
• 22. Physical, Hematological, and Histopathological Signs of Toxicity Induced by African Medicinal Plants
• 23. Biochemical Parameters in Toxicological Studies in Africa: Significance, Principle of Methods, Data Interpretation, and Use in Plant Screenings