HPLC separation and in vitro antimalarial studies of Artemisia annua plants from two different origins: Cameroon versus Luxembourg
Saleh Abu Lafi
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Background. Malaria is a devastating disease, particularly in Africa, due to development of resistance by Plasmodium falciparum against all known antimalarial drugs, including artemisinin. Therefore, the search for new antimalarial drugs is urgently needed, especially drugs that can impede the heme detoxification pathway in the malaria parasite, a crucial requirement for parasite survival in host erythrocytes. Materials and Methods. Water infusions of Artemisia annua plants from two different origins, Cameroon and Luxembourg, were used in this study. A semi-quantitative in vitro method, based on the inhibition of ferriprotoporphyrin IX (FP) biomineralisation developed by Deharo et al. , was used to reveal the differences in antimalarial activity of both plants. Reversed phase preparative liquid chromatography coupled to a photo diode array (PDA) detector was also used to test for differences in antimalarial activity. Results. Water extracts from the leaves of the Cameroon plant showed a higher potential antimalarial activity, represented by a higher ability to inhibit β-haematin formation in vitro than A. annua extracts from Luxembourg. Although extracts of the plants of both origins showed comparable efficiencies at high concentrations, the absorbance value at 405 nm of a 10% dilution of the Cameroon plant extract was 0.075, whereas it was 1.515 for the Luxembourg plant extract. The absorbance is inversely proportional to the antimalarial activity. According to the Prep-HPLC chromatogram of the Cameroon crude sample, seven major compounds at 325 nm were found. However, only four much less pronounced compounds appeared in the Luxembourg crude sample under the same chromatographic conditions and concentration. These were preliminarily identified as polyphenolic compounds. Conclusion. A. annua infusions are widely used by people who cannot afford other treatments. Depending on the cultivation locality different chemical profiles exist. This results in differences in hemozoin formation and will therefore also lead to alterations in antimalarial activity.