OVER-PRODUCTION OF LIPID RICH IN gamma-LINOLENIC ACID BY BLUE GREEN ALGA Spirulina maxima AND ITS INHIBITORY EFFECT ON CARCINOMA CELLS

摘要

Spirulina maxima accumulated a large amounts of total lipids rich in the potential pharmaceutical valuable omega-6 polyunsaturated fatty acids ((0-6 PUFAs), in particular linoleic (C_(18:2) omega 6) and gamma linolenic (gamma GLA, C_(18:3) omega 6) acids. The lipid content and fatty acid composition varied with the concentration of nitrogen in the nutrient medium. Under nitrogen depletion (51 ppm N), S. maxima contained the relatively highest quantity of total lipids, with value a 26.45% on dry weight basis (d.w). This value was significantly decreased to 10.25% (of the d.w.) with increasing of N concentration up to 410 ppm N (optimal N level). The fatty acid profile of S maxima grown in N depletion medium was characterized by the presented relatively low percentage of C16 and high percentage of omega 6-C_(18:2) (24.67%) and omega 6-C_(18:3) (34.2%) form. Also, the profile of unsaponifiable matter was altered as a result of the nitrogen concentration in the growth medium. Thus, S. maximam could bebecame an excellent source for lipid production that rich in omega-6 PUFAs. S. maxima lipids extracts at 100 and 200 ppm displayed the highest anticarcinoma factors against viability of Ehr-lich ascites carcinoma cells (EACC). These extracts did not induce any DNA fragmentation, but significantly increased the enzyme activities of lactate dehydrogenase (LDH), glutathione-S-transferase (GST) and glutathione (GSH) content in treated EACC. Therefore, S. maxima lipids extract may reduce EACC viability through membrane lyasis mechanism, rather than apoptosis induction. Therefore, S. maxima lipids could be used as chemopre-ventive agents since they are relatively non-toxic.