Various Parts of Helianthus annuus Plants as New Sources of Antimalarial Drugs.

Each part of H. annuus plants is traditionally used as medicinal remedies for several diseases, including malaria. Antimalarial activity of the leaf and the seed has already been observed; however, there is no report about antimalarial activity of the other parts of H. annuus plants. In this study, we assess in vitro and in vivo antimalarial activity of each part of the plants and its mechanism as antimalarial agent against inhibition of heme detoxification.

To investigate the antimalarial activity of various parts of H. annuus.

Various parts of the H. annuus plant were tested for in vitro antimalarial activity against Plasmodium falciparum 3D7 strain (chloroquine-sensitive), in vivo antimalarial activity against P. berghei using Peters' 4-day suppressive test in BALB/c mice, curative and prophylaxis assay, and inhibition of heme detoxification by evaluating β-hematin level.

Ethanol extract of the roots showed the highest antimalarial activity, followed by ethanol extract of leaves, with IC₅₀ values of 2.3 ± 1.4 and 4.3 ± 2.2 μg/mL, respectively and the percentage inhibition of P. berghei of 63.6 ± 8.0 and 59.3 ± 13.2 at a dose of 100 mg/kg, respectively. Ethanol extract of roots produced an ED₅₀ value of 10.6 ± 0.2 mg/kg in the curative test and showed an inhibition of 79.2% at a dose of 400 mg/kg in the prophylactic assay. In inhibition of heme detoxification assay, root and leaf ethanol extracts yielded a lower IC₅₀ value than positive (chloroquine) control with a value of 0.4 ± 0.0 and 0.5 ± 0.0 mg/mL, respectively.

There were promising results of the ethanol extracts of root of H. annuus as a new source for the development of a new plant-based antimalarial agent.