Acceptance speech – Langesse Wolde-Johannes

In this context it is very often overlooked that the solution to a poor man's health is close at hand.



Endod (Phytolacca dodecandra) is an indigenous perennial plant which has been used as a soap for washing clothes in Ethiopia for centuries.

The molluscicidal properties of Endod were discovered by Aklilu Lemma in 1964 in a small town called Adava in northern Ethiopia. It was in a small stream where people were washing their clothes with the berries of the plant that Aklilu was able to make his careful scientific observation of the death of the snails, the intermediate host of schistosoma parasites, downstream.

Interested in this observation, he later unequivocally confirmed the molluscicidal activity of the berries in his laboratory at the Institute of Pathobiology, Addis Ababa University.

Following this, a nation-wide survey and collection of different ecotypes was soon launched. A total of five hundred samples were brought to the laboratory. Sixty-five of these were selected for further study and only three were found to possess a high molluscicidal potency. These were accordingly catalogued and named as types 3, 17 and 44. Consequent studies concentrated on these three types.

The properties of this ‘Wonder plant’ soon attracted the attention of both local and expatriate scientists. Studies on the agrobotanical aspects of the plant were initiated in Ethiopia and its chemical characterization was determined in the United States with the financial support of ‘Office for Naval Research’ (ONR).

In the agrobotanical field, methods of propagation, selective pollination and identification of sites for the optimal growth of Endod were given due attention.

The chemical study put much emphasis on the identification of the active ingredients and development of different extraction protocols.

The methods of propagation used were the cutting including tissue culture approaches. Selective pollination of the types 3 and 17 with the type 44 were carried out. In an attempt to locate the habitats and environment for the optimal performance of the three identified types, experimental stations were established in different regions in Ethiopia representingthe main altitudinal zones of the country in this connection. Development and adaptation of appropriate harvesting and processing techniques went hand in hand with the different methods of propagation of the plant.

Furthermore, because the tropical environment provides suitable ideal conditions for the survival and propagation of several insect pests, studies in insect resistant types and other interconnected aspects were carried out in regions where the plant is most susceptible. Following such extensive and intensive studies, attempts were made to popularize the plant and its use for the ultimate goal of its large-scale commercial production, harvesting, processing and its application in regions badly threatened by the debilitating disease, schistosomiasis or bilharziasis.

Thus, a commendable work was done to adopt the plant in State Farms and also among private farmers in villages. Results were very encouraging. The intercropping trials now going on in State Farms with selected food crops are showing satisfactory results.

The forerunners in the chemical study of endod are Aklilu Lemma carried out both in Ethiopia and in United States and Robert Parkhurst of SRI-California in collaboration with Hostettman University of Lausanne – Switzerland and A.P. Simon of Carleton University-Canada. The principal Organic Chemist is Robert Parkhurst who identified the active ingredient as an Oleanolic acid glycosid and named it Lemmatoxin in honour of the discoverer of its molluscicidal property. They developed cheap and simple yet efficient extraction protocols of the active component. As with any bio-chemical active substance, the safety of Endod on its application to animals and environment has been thoroughly investigated both in Ethiopia and in United States. Here the works of Aklilu Lemma and Ephraim Mamo in Ethiopia and the joint support offered by ONR (USA), IDRC (Canada) and Addis Ababa University need mention for their untiring work and contribution towards the promotion of Endod.

After the two international work-shops on Endod, held in Lusaka Zambia in 1983 and Mbabone, Swaziland in 1986, collaborative efforts were encouraged more than ever before, particularly among African Countries in developing the Endod plant in the spirit of Technical Co-operation among Developing Countries (TCDC).

To facilitate this the Institute of Pathobiology, Addis Ababa University has been designated to co-ordinate the study as well as to provide Endod-5 for toxicological studies and clonal material from Endod type 44 growing in isogenic plots at our Institute. The third International Workshop is now being planned to take place in Ethiopia in May 1990.

Agrobotanical studies involving the production, processing and application of Endod-5 is in progress in Ethiopia, Zambia, Swaziland and Zimbabwe. We are dealing with a product which people have used to wash themselves and their clothing in Ethiopia for centuries and if there was a problem it should have manifested itself in some way by now. In this context it is very often overlooked that the solution to a poor man’s health is close at hand.

At long last, the prospects for Endod development and application are better now than ever before. We have a renewed dream and optimism for the widespread use of this plant for dual use as a molluscicide for the control of Schistosomiasis on a community self-help basis and as a locally producible detergent for improved hygiene, and as an additive for a foaming agent in light weight concrete-preparation. It is toward this goal that the National Chemical Corporation (NCC) of Ethiopia has taken deep interest and is now actively participating with the Institute of Pathobiology, Addis Ababa University. The results achieved in this area are very encouraging.

Endod is a natural product that has been selected by traditional Society through centuries of its use and safety for washing clothes.

The presentation of this Award will allow us to achieve our final goal more rapidly.

In conclusion, I would repeat my thanks and deep appreciation for this Award and know that all my collaborating colleagues would wish to join me in thanking the Society.

Thank you.

Dr Legesse Wolde-Yohannes
Assoc. Professor of Biology
Addis Ababa University
Aklilu Lemma Institute of PathobiologyAddis Ababa
P.O. Box 1176