The traditional medicine Spilanthes acmella, and the alkylamides spilanthol and undeca-2E-ene-8,10-diynoic acid isobutylamide, demonstrate in vitro and in vivo antimalarial activity.
Spilanthes spp. are used as traditional herbal medicines in Africa and India to treat malaria. Yet, to date, there are no data on the active constituents or the most effective extraction methods for this indication. The isolated alkylamides, spilanthol and undeca-2E-ene-8,10-diynoic acid isobutylamide, found in S. acmella Murr., were shown to have IC₅₀s of 16.5 μg/mL and 41.4 μg/mL on Plasmodium falciparum strain PFB and IC₅₀s of 5.8 μg/mL and 16.3 μg/mL for the chloroquine resistant P. falciparum K1 strain, respectively. Further investigations revealed that at relatively low concentrations, spilanthol and the water extract of S. acmella reduced the parasitemia 59% and 53% in mice infected with P. yoelii yoelii 17XNL at 5 mg/kg and 50 mg/kg, respectively. Unexpectedly, the 95% ethanol extract of S. acmella was less effective (36% reduction in parasitemia) at 50 mg/kg. These results provide the first evidence supporting S. acmella against malaria and demonstrating active constituents in S. acmella against P. falciparum.
Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Baltimore, MD 21224, USA. phytochemks@gmail.com
Kevin
K
Spelman
Delphine
D
Depoix
Megan
M
McCray
Elisabeth
E
Mouray
Philippe
P
Grellier
D000577:Amides / Q000494:pharmacology*; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D019659:Asteraceae / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D020128:Inhibitory Concentration 50; D008288:Malaria / Q000188:drug therapy; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects*; D010967:Plasmodium yoelii / Q000187:drug effects; D053284:Polyunsaturated Alkamides
D000577:Amides; D000962:Antimalarials; D005231:Fatty Acids, Unsaturated; C489347:N-isobutyl-2E-decenamide; D010936:Plant Extracts; D053284:Polyunsaturated Alkamides; C551647:undeca-2-ene-8,10-diynoic acid isobutylamide