Name: Dr Joseph Mwanzia Nguta

Phonel: +254 735 750 278

Email: joseph.nguta@uonbi.ac.ke

Research topic:

Ethnopharmacology And Toxicology Of Antimalarial Plants Used Traditionally In Msambweni, Kenya.

Abstract Of Proposal / Dissertation

Historically, compounds containing novel structure from natural origin represent a major alternative source for the discovery and development of new drugs for several diseases. This study was undertaken in order to compose detailed documentation on wild medicinal flora used against malaria, existing knowledge, attitudes and practices related to malaria recognition, control and treatment; ethnodiagnostic skill used by the Msambweni community as a lead to traditional bioprospecting and to evaluate the toxicological activity of the crude extracts in brine shrimp bioassay using Artemia salina Leach (Artemiidae).

Study I was conducted with herbalists (Traditional Medical Practitioners) to document medicinal plants that are traditionally used by the Msambweni community of Kenyan South Coast to treat malaria, where the disease is endemic. Herbalists were interviewed by administration of semi structured questionnaires in order to obtain information on medicinal plants traditionally used for the treatment of malaria. Focused group discussions held with the herbalists supplemented the interview and questionnaire survey.  Twenty six species of plants in twenty four genera distributed in 20 families were reported to be used in this region for the treatment of malaria. Labiatae, Rutaceae and Liliaceae families had each eleven percent of the plant species reported and represented the species that are most commonly used. Thirteen plant species, namely; Aloe deserti Berger (Liliaceae), Launea cornuta (Oliv and Hiern) C. Jeffrey (Compositae), Ocimum bacilicum L. (Labiatae), Teclea simplicifolia (Eng) Verdoon (Rutaceae), Gerranthus lobatus (Cogn.) Jeffrey (Cucurbitaceae), Grewia hexaminta Burret. (Tiliaceae), Canthium glaucum Hiern. (Rubiaceae), Amaranthus hybridus L. (Amaranthaceae), Combretum padoides Engl and Diels. (Combretaceae), Senecio syringitolius O. Hoffman. (Compositae), Ocimum suave Willd (Labiatae), Aloe macrosiphon Bak. (Liliaceae) and Laudolphia buchananii (Hall.f) Stapf. (Apocynaceae) are documented from this region for the first time for the treatment of malaria.

 Study II was conducted with community members to document herbal medicines used in the treatment of malaria as well as the existing knowledge, attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya. Data was collected using semi structured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey. The respondents were found to have a good understanding of malaria and could distinguish it from other disease conditions characterized by increased body temperature. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals at an average of four times a year. Community members avoided mosquito bites by using mosquito nets, clearing bushes around their homesteads and burning plant parts to generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty five genera distributed in twenty four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria.

Study III was conducted with community members to systematically document ethnophytotherapeutic remedies, ethnodiagnostic skills and related traditional knowledge utilized by the Digo community of the Kenyan Coast to diagnose malaria as a lead to traditional bioprospecting. The study was carried out in three Digo villages of Diani sub-location between May 2009 and December 2009. Data was collected using semi-structured interviews, and open and close-ended questionnaires. A total of sixty (60) respondents (34 men and 26 women) provided the targeted information. The results showed that the indigenous knowledge of Digo community on malaria encompasses not only the symptoms of malaria but also the factors that are responsible for causing malaria, attributes favoring the breeding of mosquitoes and practices employed to guard against mosquito bites or to protect households against malaria. This knowledge is closely in harmony with scientific approaches to the treatment and control of the disease. The Digo community uses sixty (60) medicinal plants distributed in fifty two (52) genera and thirty one (31) families to treat malaria. The most frequently mentioned symptoms were fever, joint pains and vomiting while the most frequently mentioned practices employed to guard against mosquito bites and/or to protect households against malaria was burning of herbal plants such as Ocimum suave and ingestion of herbal decoctions and concoctions. The Digo community has abundant ethnodiagnostic skills for malaria which forms the basis of their traditional bioprospecting techniques. They also have abundant traditional knowledge about the causes of malaria and ethnophytotherapeutic remedies.

Artemia salina, the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemicals and natural products. In study IV, the Medium Lethal Concentrations (LC50 values) of 170 crude plant extracts and positive controls, cyclophosphamide and etoposide were determined using Artemia salina. Out of the 85 organic extracts (Chloroform/Methanol, 1:1) screened for activity against Artemia salina larvae, 46 (54%) of the crude extracts demonstrated activity at or below 100µg/ml, and were categorized as having strong cytotoxic activity, 35 (41.2%) of the crude extracts had LC50 values between 100µg/ml and 500µg/ml, and were categorized as having moderate cytotoxicity, 2 (2.4%) of the crude extracts had LC50 values between 500µg/ml and 1000µg/ml, and were considered to have weak cytotoxic activity, while 2 (2.4%) of the crude extracts had LC50 values greater than 1000µg/ml and were considered to be non toxic. Approximately 19% (16) of the aqueous  extracts demonstrated activity at or below 100 μg/ml and were considered to have strong cytotoxic activity, 39% (33) of the screened aqueous crude extracts had LC50 values between 100µg/ml and 500µg/ml and were considered to be moderately cytotoxic, 15% (13) of the crude extracts had LC50 values between 500µg/ml and 1000µg/ml and were considered to have weak cytotoxic activity while 27% (23)  of the aqueous extracts had LC50 values greater than 1000µg/ml and were categorized as non toxic.The positive controls, cyclophosphamide and etoposide exhibited strong cytotoxicity with LC50 values of 95µg/ml and 6µg/ml respectively in a 24 hour lethality study, validating their use as anticancer agents. In the current study, 97.6% of all the screened organic extracts and 73% of the investigated aqueous extracts demonstrated LC50 values <1000 μg/ml, indicating the presence of bioactive compounds responsible for the observed toxicity. This calls for in depth in vivo toxicological studies and chemical investigation for isolation of bioactive compounds responsible for the observed toxicologic activity. It is concluded that some of the plants used would not make safe antimalarial drugs, and instead could be a source of novel scaffolds againt cancer.

In summary the studies above indicate that many species of antimalarial plants are used by the Msambweni community to prevent and treat malaria. The good knowledge on the disease by the study community can be utilized as a lead to bioprospecting of novel remedies accessible to the rural poor. Majority of the species identified have strong cytotoxic activity in brine shrimp (Artemia salina) assay, indicating that they could not make safe antimalarial remedies. In depth studies would now be needed to find the active compounds behind these toxic activities that could be used as biomarkers in development of anticancerous drugs.

Future plans

To serve as a faculty, mentor and a research scientist.

Supervisors (name and email address)

Prof. James M. Mbaria, BVM, MSc, PhD.

Email address:  james.mbaria@uonbi.ac.ke; mbariajim@yahoo.com

Professor Peter K. Gathumbi, BVM, MSc, PhD.

Email address:  gathumbi@uonbi.ac.ke

Dr. Daniel W. Gakuya, BVM, MSc, PhD.

Email address: waweru70@hotmail.com

Prof. Stephen G. Kiama, BVM, MSc, PhD.

Email address: kiama123@yahoo.com


Publications / manuscripts (if any yet)


J.M. Nguta. Ethnopharmacology and Toxicology of Antimalarial Plants used traditionally in Msambweni, Kenya (PhD Thesis, University of Nairobi, 2011).



15 October 2015, Kenyan uncovers antituberculosis plants

Postdoc fellow Joseph Mwanzia Nguta from Kenya talks about his research into the antituberculosis properties of various plants traditionally used in Ghana to treat respiratory problems. His research in this neglected field has led to some exciting discoveries. Read more



Awarded a full travel grant (Covering Registration; Visa application; Return airfare and Accommodation)  by the Asian African Society for Mycobacteriology (AASM) to present an invited lecture at the 1st Asian African Congress for Mycobacteriology (1st AACM-2015) during March, 7-13, 2015 at the Isfahan International Conference Centre, Isfahan, Iran.


Awarded a Grant of:  $1,970 by Science Initiative Group (SIG) under Competitive Fund for Regional Initiative for Science and Education (RISE) Graduates on September 16, 2014. Project: Purchase of office equipment and teaching aids for mentoring students

Awarded a post-doctoral fellowship by Bill and Melinda Gates Foundation to conduct research on drug discovery against tuberculosis from plant biodiversity at Noguchi Memorial institute for Medical Research (NMIMR), College of Health Sciences, University of Ghana from April 2014-April 2016



Webometrics ranking (March, 2015): Position 97, among top 100 Kenyan scientists (http://www.webometrics.info/en/node/106)


1. J. M. Nguta, R. Appiah-Opong, A. K. Nyarko, D. Yeboah-Manu, G. A. Addo, Current perspectives in drug discovery against tuberculosis from natural products. Int. J. Mycobacteriol.

(2015), http://dx.doi.org/10.1016/j.ijmyco.2015.05.004 (In press).

2.  J. M. Nguta, R. Appiah-Opong, A. K. Nyarko, D. Yeboah-Manu, G. A. Addo, Medicinal plants used to treat TB in Ghana, International Journal of Mycobacteriology 4 (2015) 116-123.

3. David Njenga, Beatrice Irungu,  James Mbaria, Charles Mutai,  Joseph Nguta, Antiplasmodial, Cytotoxic and Acute Toxicity Activities of Vernonia lasiopus O. Hoffman,  African Journal of Pharmacology and Therapeutics, 4, issue 1 (2015) 16-20.


4. George Gicharu Mwangi, John Maina Wagacha, Joseph Mwanzia Nguta, and James M. Mbaria. Brine shrimp cytotoxicity and antimalarial activity of plants traditionally used in treatment of malaria in Msambweni district. Posted online on December 11, 2014. Pharmaceutical Biology. (doi:10.3109/13880209.2014.935861). Early Online: 1–6


5. Magrate M. Kaigongi, Saifuddin. F. Dossaji, Joseph. M. Nguta, Catherine.W. Lukhoba, Fredrick. M. Musila. Antimicrobial Activity, Toxicity and Phytochemical Screening of Four Medicinal Plants Traditionally Used in Msambweni District, Kenya. Journal of Biology, Agriculture and Healthcare, ISSN 2224-3208 (Paper) ISSN 2225-093X (Online),Vol.4, No.28, 2014.


6. Douglas Ongeri Ochora, Dossaji Saifudin Fidahusein, Joseph Mwanzia Nguta, Elijah M. Akunda.  Antimalarial activity and acute toxicity of four plants traditionally used in treatment of malaria in Msambweni District of Kenya. European International Journal of Science and Technology Vol. 3 No. 7 September, 2014.


7. Caroline Kathambi Murithi; Dossaji Saifudin Fidahusein; Joseph Mwanzia Nguta; Catherine Wanjiru Lukhoba. Antimalarial activity and in vivo toxicity of selected medicinal plants naturalised in Kenya. International Journal of Education and Research. Vol. 2 No. 5 May 2014


8. Isaac Omwenga, L. Kanja, J. Nguta, J. Mbaria and P. Irungu. Assessment of lead and cadmium residues in farmed fish in Machakos and Kiambu counties, Kenya. Toxicological & Environmental Chemistry, 2014. http://dx.doi.org/10.1080/02772248.2014.911541


9. Joseph Mwanzia Nguta*, James Mucunu Mbaria and Winchester David Mvula. Brine shrimp toxicity and in vitro antimicrobial activity of Piliostigma thonningii (Schum.) Milne-Redh. [Leguminosae-Caesalpinioideae] from Kenya and Malawi against some pathogens of human and veterinary importance. Journal of Veterinary Medicine and Animal Health, Vol. 5(9), pp. 251-256, September, 2013. DOI 10.5897/JVMAH13.0208. © 2013 Academic Journals http://www.academicjournals.org/JVMAH


10. J.M. Nguta, J.M. Mbaria. Brine shrimp toxicity and antimalarial activity of some plants traditionally used in treatment of malaria in Msambweni district of Kenya. Journal of Ethnopharmacology 148 (2013) 988-992.


11. James M. Mbaria, Charles Ochodo and Joseph Mwanzia Nguta. Forensic case of lead poisoning from a battery manufacturing company in Nakuru, Kenya. Japanese Journal of Veterinary Research 61 (Supplement): S64-S66, 2013. 


12. M.F.Musila, S.F.Dossaji, J.M.Nguta, C.W.Lukhoba, J.M.Munyao. In vivo antimalarial activity, toxicity and phytochemical screening of selected antimalarial plants. Journal of ethnopharmacology 146 (2013) 557-561


13. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, J.D. Kabasa, S.G.Kiama. Cytotoxicity of antimalarial plant extracts from Kenyan biodiversity to the brine shrimp, Artemia salina L. (Artemiidae). Drugs and Therapy Studies 2012; volume 2:e12


14. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, J.D. Kabasa, S.G.Kiama. Evaluation of Acute Toxicity of Crude Plant Extracts from Kenyan Biodiversity using Brine Shrimp, Artemia salina L. (Artemiidae). The Open Conference Proceedings Journal, 2012, 3, 30-34


15.Gakuya DW, Mbaria JM, Kiama SG, Gathumbi PK, Mathiu M, Nguta JM. Ethnoveterinary Medicine: The Prospects of Integrating Medicinal Plant Products in Veterinary Medicine in Kenya.  Kenya Veterinarian 35 Issue 2 (2011). Pp. 67-76


16. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, J.D. Kabasa, S.G.Kiama. Biological screening of Kenyan medicinal plants using Artemia salina L. (Artemiidae). Pharmacologyonline 2: 458-478 (2011) 


17. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, J.D. Kabasa, S.G.Kiama. Ethnodiagnostic skills of the Digo community for malaria: A lead to traditional bioprospecting.

Frontiers in Pharmacology. (2011) Vol. 2: 30. Doi: 10.3389/fphar.2011.00030


18. J.M. Nguta, J.M. Mbaria. Bioavailability of Cobalt, Zinc and Selenium and Anthelmintic effects of fortified and non-fortified albendazole in sheep. Kenya Veterinarian 35 Issue 1(2011). Pp 9-17


19. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, S.G.Kiama. Traditional antimalarial phytotherapy remedies used by the South Coast community, Kenya. Journal of Ethnopharmacology, 131(2010) 256-267


20. J.M. Nguta, J.M. Mbaria, D.W.Gakuya, P.K.Gathumbi, S.G.Kiama. Antimalarial herbal remedies of Msambweni, Kenya. Journal of Ethnopharmacology 128(2010) 424-432




1. Natural products: An exciting source of new pharmacophores against malaria. Presented as an oral presentation In: The 8th Biennial Scientific Conference and the 46th Kenya Veterinary Association Annual Scientific Conference held at Safari Park Hotel, Nairobi, Kenya, from 25th to 27th April 2012.


2. Cytotoxicity of antimalarial plant extracts from Kenyan Biodiversity to the Brine Shrimp, Artemia salina L. (Artemiidae). Presented as a Session lecture (SL) In: The 4th International Conference on Drug Discovery and Therapy (4th ICDDT) 2012, at Dubai men’s college, Dubai, United Arab Emirates, February 12th-15th, 2012, Dubai, UAE.


3. Plants as source of drugs: Ethnopharmacology, Pharmacology and Toxicology of selected antimalarial herbal plants from Msambweni district, South coast Kenya. In: The Proceedings of a RISE AFNNET workshop-University of Nairobi Node in Chak Guest House, Nairobi, on 13th December 2011.


4. Biological screening of Kenyan antimalarial plant extracts in brine shrimp bioassay. In: The first international congress on Human-Animal Interface (ICOPHAI): Impact, Limitations and Needs in Developing Countries in the United Nations Conference Centre, Addis Ababa, Ethiopia from September 12th to 18th, 2011, sponsored by USDA/APHIS in collaboration with Ohio State University. And RISE-AFNNET


5. Exploiting Natural Products from African Biodiversity in Pest Management: from Extraction of Plant chemicals to Expression in GMOs. In: The proceedings of a continuous professional development (CPD) workshop on, “Advances in pest management and the role of veterinarians” organized and held at the Department of Public Health, Pharmacology and Toxicology on 16/09/2011.


6. Toxicity of crude plant extracts and antitumour drugs in the Brine Shrimp Bioassay. In: The Proceedings of the Ist International Scientific Conference, College of Health Sciences, University of Nairobi, Kenya during June 15-17th, 2011. (Poster No. 42).


7.Natural products from plant biodiversity and malaria: In: The 12TH International Symposium on Natural Product Chemistry and Related Biological Sciences, International Centre for Chemical and Biological Sciences (ICCBS), University of Karachi, Pakistan during November 22-25, 2010.


8. Development of ethnomedicines for management of malaria in Msambweni district, Kenya: In: The Proceedings of a Workshop on Regional Networks in Africa, held on October 5-6th, 2010 at the Kopanong Hotel and Conference Centre in Benoni, South Africa, near Johannesburg.


9. Ethnodiagnostic Skills of the Digo Community for malaria: A lead to traditional bioprospecting?: In: The Proceedings of the Ist East and Central Africa Regional Symposium for the Carnegie-RISE Fellows held on September 15th, 2010 at Royale Imperial Hotel, Kampala-Uganda, East Africa.


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  • 15th October 2015.

  • Dr. Joseph Nguta uncovers antituberculosis plants, he talks about his research  into the antituberculosis properties of varous plants traditionally used in Ghana.Read More ....

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  • Dr. Irene Kamanja graduated on 29th August 2014 with PhD in Pharmocology and Toxicology  and Dr. Ronald O.Onzago and Dr. Zachary M. Rukenya Graduated on the same day with Msc in Natural Products and Bioprospecting.
  • Dr. Ronald O.Onzago and Dr. Zachary M. Rukenya  attended 48th Annual Scientific Conference on 23rd to 26th April 2014 at Boma Inn Hotel , Eldoret. The them of the conference is "Improving Veterinary Governance and Service Delivery in a Devolved system for Sustainable Development".
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  • Dr.Zachary  Rukenya Rise Afnnet fellow presented his paper on 'Current challanges and approaches to managment of antimicrobial drug resistance  at scientific veterinary symposium at Kampala Uganda on 13th December 2013.Read More.....
  • Dr.Johnson Nasimolo & Ms. Clare Njoki Rise Afnnet Fellows graduate in a colour ceremony at University of Nairobi on 6th December 2013.
  • Dr.Catherine Kaluwa, Dr. Dominic Ochwangi, Dr. James Kuria and Ms. Karambu Muriithi  attended the15th Symposium of the Natural Products Chemistry Research Network for Eastern and Central Africa (NAPRECA) from 3rd  -10th December, 2013  at Khartom Sudan.
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  • Dr.Catherine Kaluwa and Dr.Johnson Nasimolo attended the 19th International Scientific Conference  on Basic and Clinical Research for inproved Health on 11th-13th 2013 in Southern Sun,Mayfair,Nairobi,Kenya.

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  • Ms.Karambu Mureithi, a Rise Afnnet Fellow graduates with MSc. from University of Nairobi.

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  • Ms. Karambu Muriithi, RISE-AFNNET fellow presented her research paper at Indigenous Plant Forum 2013 Conference

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  • RISE AFNNET PostDoc Fellow, Dr. Joseph Nguta attends the 2nd International Conference on Pathogens at the Human-Animal Interphase, Brazil

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  • Dr. Johnson Nasimolo, RISE-AFNNET fellow at the 11th SONA International Conference  in Rabat Morocco.

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  • Dr Zachary Rukenya and Dr Ronald Okindo, RISE-AFNNET fellows attended and presented papers

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  • The RISE AFNNET Workshop Nairobi Node was successfully held at KCB Karen on 26th and 27th October 2012.

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