Effects of the angiotensin II Ala-scan analogs in erythrocytic cycle of Plasmodium falciparum (in vitro) and Plasmodium gallinaceum (ex vivo)

• DOI: 10.1016/j.exppara.2015.02.006
• Publication Date: 2015-02-24T01:00:28Z
• Authors: Adriana Farias Silva; Leandro de Souza ...; Flávio Lopes Alves; Marcelo Der Toros...; Ana Acacia de SáP...; Antonio Miranda; Margareth LaraCap...; Vani Xavier Oliveira
• Keywords: Plasmodium gallinaceum; Plasmodium (life cycle); Ex vivo

The anti-plasmodium activity of angiotensin II and its analogs have been described in different plasmodium species. Here we synthesized angiotensin II Ala-scan analogs to verify peptide-parasite invasion preservation with residue replacements. The analogs were synthesized by 9-fluorenylmethoxycarbonyl (Fmoc) and tert-butyloxycarbonyl (t-Boc) solid phase methods, purified by liquid chromatography and characterized by mass spectrometry. The results obtained in Plasmodium falciparum assays indicated that all analogs presented some influence in parasite invasion, except [Ala(4)]-Ang II (18% of anti-plasmodium activity) that was not statistically different from control. Although [Ala(8)]-Ang II presented a lower biological activity (20%), it was statistically different from control. The most relevant finding was that [Ala(5)]-Ang II preserved activity (45%) relative to Ang II (47%). In the results of Plasmodium gallinaceum assays all analogs were not statistically different from control, except [Ala(6)]-Ang II, which was able to reduce the parasitemia about 49%. This approach provides insight for understanding the importance of each amino acid on the native Ang II sequence and provides a new direction for the design of potential chemotherapeutic agents without pressor activity.