Non-destructive methods for estimation of Crop Growth Rate and Harvest Index of the oil plam (Elaeis guineensis JACQ.) are described . These methods were applied in a selection experiment, and the importance of considering Harvest Index, Leaf Area Index and planting density in selecting for increased yields is discussed .
Artemisinin is an endoperoxide sesquiterpene lactone isolated from the Chinese medicinal plant Artemisia annua L. It has been widely used in South-East Asia and Africa as an effective drug against sensitive and multidrug-resistant Plasmodium falciparum malaria. A monoclonal antibody (mAb), designated as 3H2, was generated with artesunate-bovine serum albumin conjugate as the immunogen. mAb 3H2 was used to develop a highly sensitive and specific indirect competitive enzyme-linked immunosorbent assay (icELISA) for artemisinin. The concentration of analyte producing 50% of inhibition (IC(50)) and the working range of the icELISA were 1.3 and 0.2-5.8 ng/mL, respectively. The mAb 3H2 recognized the artemisinin analogs artesunate, dihydroartemisinin, and artemether with cross-reactivity of 650%, 57%, and 3%, respectively, but negligibly recognized deoxyartemisinin and the artemisinin precursors arteannuin B and artemisinic acid. The average recoveries of artemisinin fortified in A. annua samples at concentrations from 156 to 5,000 microg/g determined by icELISA ranged from 91% to 98%. The icELISA was applied for the determination of artemisinin in different wild A. annua samples and the results were confirmed by high-performance liquid chromatography (HPLC) analysis. The correlation coefficient (R(2)) between the two assays was larger than 0.99, demonstrating a good agreement between the icELISA and HPLC results. This ELISA is suitable for quality assurance of A. annua L. materials.
BackgroundArtemisinin-based combination therapy (ACT) plays an indispensable role in malaria control and elimination. However, the circulation of counterfeit, substandard drugs has greatly threatened malaria elimination campaigns. Most methods for the analysis of artemisinin and its derivatives require expensive equipment and sophisticated instrumentation. A convenient, easy-to-use diagnostic device for rapid evaluation of the quality of artemisinin drugs at the point-of-care is still lacking. In this study a lateral flow dipstick immunoassay was developed for qualitative and semi-quantitative analysis of artesunate (ATS) and dihydroartemisinin (DHA) in anti-malarial drugs.MethodsThis assay was based on a monoclonal antibody (mAb) raised against ATS. ATS-bovine serum albumin and goat anti-mouse IgG, used as the test capture reagent and the control capture reagent, were coated on the nitrocellulose membrane to form the test line and control line, respectively. The conjugate pad was saturated with the gold-labelled anti-ATS mAb.ResultsThe indicator range of the dipsticks, defined as lowest concentration of the target analytes between which the test line was not visible, were 100-200 and 200-500 ng mL-1 for ATS and DHA, respectively. No competitive inhibition was observed up to 5,000 ng mL-1 of quinine, chloroquine diphosphate salt, primaquine phosphate, pyrimethamine, lumefantrine, amodiaquine, piperaquine tetraphosphate tetrahydrate or pyronaridine tetraphosphate. Semi-quantitative analysis of ATS and DHA in commercial drugs and raw drug materials with the dipsticks produced result agreeable with those determined by high performance liquid chromatography (HPLC). Storage test showed that the indicator range for artemisinins remained unchanged after a week at 37°C and increased four-folds after six months of storage at 4°C or ambient temperature.ConclusionsThe new selected mAb 3D82G7 with high avidity and broad cross reactivity for artemisinins was used to develop and optimize a dipstick immunoassay for qualitative and semi-quantitative analysis of ATS and DHA in anti-malarial drugs. The semi-quantitative analysis of ATS and DHA in commercial drugs and raw drug materials, and the specificity test of the artemisinin-related drugs both proved the accurate performance of the developed dipsticks for semi-quantitation of ACT samples. The dipstick may be used as a point-of-care device for identifying substandard and counterfeit ATS- and DHA-containing anti-malarial drugs.
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