In 1972, the Chinese isolated and characterized artemisinin, an antimalarial drug present in the Chinese herb Qinghao (Artemisia annua). This herb has been used for malaria therapy in China for over 1,000 years. In the developing countries of the world it has been estimated that in excess of 150 million cases of malaria exist. Alarmingly this fact is coupled with the apparent spread of strains of Plasmodium falciparum which are resistant to chloroquine as well as alternative drugs pyrimethamine/sulfonamide combinations. Studies have shown that artemisinin has a high level of schizonticidal activity against the chloroquine-resistant malaria and is non-toxic. However, artemisinin occurs at very low levels in A. annua. The objective of this Phase I proposal is to develop a monoclonal antibody to artemisinin. The antibody will then be used to select plants which are high yielders of artemisinin. This selction will lead to Phase II cultivation of these selected "high yielders" initially using plant tissue culture. This has immediate commercial application in the efforts against malaria, in that high yielding plants may be propagated providing a source significantly large enough to supply sufficient artemisinin for drug use. The monoclonal antibody could further be used in bioavailability, pharmakinetic and drug monitoring studies.