Natural compounds, mostly from plants, are a potential source of antimalarial
drugs due to presence of various secondary metabolites with variety of
structures and different biological activities. Amongst the secondary plant metabolites,
quassinoids, sesquiterpene lactone and alkaloids are the most important metabolites
with diverse bio-potencies. Therefore, due to the wide use of alkaloid derived drugs,
antimalarials can be grouped into two groups: alkaloidal antimalarials and nonalkaloidal
antimalarials. By virtue of their chemical structure, the alkaloidal
antimalarials are further classified into various classes (Bisbenzylisoquinolines,
azaanthracene alkaloids, protoberberine and aporphine-benzylisoquinolines, morphinan
alkaloids, naphthylisoquinolines, indoloquinolone alkaloids, indole alkaloids,
benzofenantridine, furoquinolines and acridone, tetrahydroquinolines etc.). Apart from
the bio-potency of the alkaloids, some other chemical entities (non-alkaloidal) show
marked antimalarial activity which includes tannins, quassinoids, sesquiterpene
lactones, limonoids, flavonoids, chromones, xanthones, quinones and other
miscellaneous phenolic compounds and related compounds. This compilation covers
most of recently published alkaloidal and non-alkaloidal antimalarial natural
compounds with antiplasmodial and antimalarial properties published over last two
decades. The structure, chemistry and evaluation of antimalarial activity of the
compounds by in vitro and in vivo assays have been highlighted. Several patents
published focusing on the phenyacetonitrile, bisquinoline, 4-amino quinoline, spiro and
dispiro-1,2,4- trioxolane, phenyl(thio)urea deoxythymidine moieties as potent
antimalarials have also been discussed in the current study. Besides, this review article
also compiles the promising antimalarial compounds patented during the last two
decades.
Keywords: Artemisinin, Alkaloids, Antimalarial, Flavonoids, Malaria, Quinine.
