The objective of the present study was to evaluate the in vitro and in vivo anti-cancer effect of Nigella sativa L. seed extracts. The essential oil (IC 50 = 0.6%, v/v) and ethyl acetate (IC 50 = 0.75%) extracts were more cytotoxic against the P815 cell line than the butanol extract (IC 50 = 2%). Similar results were obtained with the Vero cell line. Although all extracts had a comparable cytotoxic effect against the ICO1 cell line, with IC 50 values ranging from 0.2 to 0.26% (v/v), tests on the BSR cell line revealed a high cytotoxic effect of the ethyl acetate extract (IC 50 = 0.2%) compared to the essential oil (IC 50 = 1.2%). These data show that the cytotoxicity of each extract depends on the tumor cell type. In vivo, using the DBA2/P815 (H 2 d ) mouse model, our results clearly showed that the injection of the essential oil into the tumor site significantly inhibited solid tumor development. Indeed, on the 30th day of treatment, the tumor volume of the control animals was 2.5 ± 0.6 cm 3 , whereas the tumor volumes of the essential oil-treated animals were 0.22 ± 0.1 and 0.16 ± 0.1 cm 3 when the animals were injected with 30 µL (28.5 mg)/mouse and 50 µL (47.5 mg)/mouse per 48 h (six times), respectively. Interestingly, the administration of the essential oil into the tumor site inhibited the incidence of liver metastasis development and improved mouse survival. CorrespondenceA. Zyad

Erythrocytes infected with Plasmodium falciparum or Plasmodium knowlesi efficiently incorporated radioactive serine into phosphatidylserine (PtdSer), phosphatidylethanolamine (PtdEtn) and phosphatidylcholine (PtdCho). Serine was also metabolized into ethanolamine (Etn) and phosphorylethanolamine (P-Etn) via direct serine decarboxylation ; this is a major phenomenon since together these metabolites represent 60 % of total radioactive water-soluble metabolites. They were identified by reverse-phase HPLC and two TLC-type analyses and confirmed by alkaline phosphatase treatment, which depleted the radioactive P-Etn peak completely with a concomitant increase in that of Etn. In the presence of 5 µM labelled serine, radioactivity appeared in Etn and P-Etn after a 25 min lag period, and isotopic equilibrium was reached at 40 and 95 min respectively. There was a similar lag period for PtdEtn formation, which accumulated steadily for at least 180 min. Incorporation of serine into phospholipids and water-soluble metabolites increased in the presence of up to 500 µM external serine. An apparent plateau was then reached for all metabolites except intracellular serine and Etn. Exogenous Etn (at 20 µM) induced a concomitant dramatic decrease in serine incorporation into P-Etn and all phospholipids, but not

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