Synthesis and in vitro antimalarial activity of alkyl esters of gallate as a growth inhibitor of plasmodium falciparum

This study is aimed to synthesize alkyl esters gallate and determine its in vitro antimalarial activity against parasite Plasmodium falciparum. Fourteen compounds of alkyl esters gallate were synthesized by esterification of the carboxyl group of gallic acid with a series of alkyl alcohols, as well as methoxylation of the hydroxy groups on the aromatic ring of gallic acid. Antimalarial activity of the synthesized alkyl esters gallate were expressed by IC50 value, with gallic acid as an original compound and artemisin as a positive control. Compared to gallic acid, eleven synthesized compounds of alkyl esters gallate, have a greater antimalarial activity against Plasmodium falciparum. On the other hand, three compounds, that are propyl gallate, butyl gallate and trimethoxy methyl gallate, showed a lower antimalarial activity. Moreover, compared to gallic acid (IC50: 194.86 mM) and artemisin (IC50: 0.5 mM), two synthesized compounds of alkyl gallates, namely methyl gallate and hexyl gallate exhibited the stronger antimalarial activity against Plasmodium falciparum, with IC50 value of 0.03 mM and 0.11 mM, respectively. Our result clearly demonstrated that methyl gallate and hexyl gallate as a promising candidate for the new antimalarial agents.