Effective Antimalarial Activities of α-Hydroxy Diynes Isolated from Ongokea gore.

Three diynes, octadec-17-ene-9,11-diynoate ethyl (1: ), 8-hydroxy-octadeca-13,17-diene-9,11-diynoate ethyl (2: ), and 8-hydroxy-octadec-13-ene-9,11-diynoate ethyl (3: ), were isolated from Ongokea gore seed oil. The structure assignment of these three compounds was based according to chemical and spectroscopic data. They were screened against Plasmodium falciparum, the parasite that causes malaria. In vitro micro-test (Mark III, supported by the World Health Organization) was developed to assess the response of P. falciparum to the isolated three compounds, and statistical analysis were performed for determination of the concentration that inhibits 50% of the parasite maturation (IC50). Two of the three diynes (2: and 3: ) showed a very effective in vitro antimalarial activity with an IC50 of 4.5 and 1.7 µM, respectively. Compound 3: exhibited better activity than quinine (IC50 1.9 µM), the drug reference, while compound 1: had no antimalarial activity (IC50 > 125 µM). In the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity screening, all compounds showed no toxicity (mean IC50 of 90 µM for each compound).

Antisickling activity of butyl stearate isolated from Ocimum basilicum (Lamiaceae).

OBJECTIVE: To perform phytochemical analyses on the leaves of Ocimum basilicum L. (O. basilicum), to elucidate the structure of isolate and then perform the antisickling activity on the crude extract and on the isolate. METHODS: The Emmel test performed on the acidified methanolic extract of this plant was used to evaluate the antisickling activity. The structure characterization of the active compound was performed using chromatographic techniques for the separation and the spectroscopic ones for structure elucidation (1H-NMR, 13C-NMR, COSY, HMBC). RESULTS: The chemical screening on the crude extract revealed the presence of polyphenols (flavonoids, anthocyanins, leucoanthocyanins, tannins, quinones) alkaloids, saponins, triterpenoids and steroids. The obtained extract after evaporation yielded 34.50 g (11.5%) out of 300 g of powdered leaves of O. basilicum. The acidified methanolic extract and butyl stearate showed an interesting antisickling activity. CONCLUSIONS: The acidified methanolic extract and butyl stearate from O. basilicum displayed a good antisickling activity. To the best of our knowledge, this is the first time to report the antisickling activity of this compound in this plant. The synthesized compound presented the same spectroscopic characteristics than the natural one and the antisickling activities of its derivatives are understudying.