Author:

Keywords:

Animals, Antimalarials, Antineoplastic Agents, Chloroquine, Chromatography, Thin Layer, Diterpenes, Drug Resistance, Microbial, Drug Screening Assays, Antitumor, Ergosterol, Fluorouracil, Humans, Inhibitory Concentration 50, Kenya, L-Lactate Dehydrogenase, Lamiaceae, Plants, Medicinal, Plasmodium falciparum, Skin Neoplasms, Tumor Cells, Cultured, Science & Technology, Life Sciences & Biomedicine, Plant Sciences, Chemistry, Medicinal, Pharmacology & Pharmacy, ANTIMALARIAL ACTIVITY, MALARIA, DERIVATIVES, ARTEMISININ, RESISTANCE, EXTRACTS, PLANTS, In Vitro Techniques, 03 Chemical Sciences, 06 Biological Sciences, 11 Medical and Health Sciences, Medicinal & Biomolecular Chemistry, 4208 Traditional, complementary and integrative medicine

Abstract:

Ajuga remota is the most frequently used medicinal herb for malaria treatment in Kenya. Its two known isolates ajugarin-1 (1) and ergosterol-5,8-endoperoxide (3) and a new isolate 8-O-acetylharpagide (2) were evaluated for their in vitro antiplasmodial activity. Ajugarin-1 was moderately active, with an IC(50) of 23.0 +/- 3.0 microM, as compared to chloroquine (IC(50) = 0.041 +/- 0.003 microM) against the chloroquine-sensitive (FCA 20/GHA) strain of Plasmodium falciparum. Ergosterol-5,8-endoperoxide was about 3x as potent (IC(50) = 8.2 +/- 1.1 microM), while 8-O-acetylharpagide, whose structure was established by spectroscopic evidence, was inactive. Both ajugarin-1 and ergosterol-5,8-endoperoxide did not exhibit cytotoxicity against A431 (skin carcinoma) cell line, but 8-O-acetylharpagide was significantly cytotoxic. This iridoid glucoside, which has been formerly isolated from Ajuga decumbens, was identified in A. remota for the first time.