FREE FATTY-ACID FUNCTIONS FROM SOME VEGETABLE-OILS EXHIBIT REDUCED SURVIVAL TIME-SHORTENING ACTIVITY IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

Previously, we demonstrated that several vegetable oils that included low-erucic rapeseed oil markedly shortened the survival time (by simil ar to 40%) of stroke-prone spontaneously hypertensive (SHRSP) rats as compared with perilla oil, soybean oil, and fish oil. We considered th at a factor other than fatty acids is toxic to SHRSP rats, because the survival time-shortening activity could not be accounted for by the f atty acid compositions of these oils. In fact, a free fatty acid (FFA) fraction derived from lipase-treated rapeseed oil was found to be ess entially devoid of such activity. A high-oleate safflower oil/safflowe r oil/perilla oil mixture exhibited a survival time-shortening activit y comparable to that of rapeseed oil, but the activity of this mixed o il was also reduced by lipase treatment. A partially hydrogenated soyb ean oil shortened the survival time by similar to 40%, but a FFA fract ion derived from lipase-treated partially hydrogenated soybean oil sho rtened it by 13% com pared with soybean oil. Fatty acid compositions o i the rapeseed oil and a FFA fraction derived from lipase-treated rape seed oil were similar, but those of hepatic phospholipids of rats fed the oil and FFA were slightly but significantly different. These re su its support the interpretation that the survival time-shortening activ ity exhibited by some vegetable oils is due to minor components other than fatty acids, and that an active component(s) were produced in or contaminated soybean oil during the partial hydrogenation processes.