A Density Functional Study of 15N Chemical Shielding Tensors in Neocryptolepine Derivatives

Neocryptolepine, cryptolepine, and their analogous have shown in vitro activity against Plasmodium falciparum, the most dangerous among Plasmodium species and responsible for malaria infections in human. Malaria, the major parasitic infection in many tropical and subtropical regions is leading to more than one million deaths out of 400-500 million cases observy each year. A computational study was carried out to investigate the relationship between the 15N shielding tensors of indol and quinoline nitrogen’s and their antiplasmodial activity in neocryptolepine derivatives. The calculations were performed with the B3LYP method and 6–311++G** standard basis sets using the Gaussian 98 suite of programs. The results show the σ11 is highly influenced due to the substitution for both indol and nitrogen and may be used as a probe the activity of neocryptolepine antiplasmodial derivatives. Keywords: Malaria, Antiplasmodial activity, Drug, Neocryptolepine, NMR, DFT calculations.