The neurotoxic effect of palmyrah (Borassus flabellifer) flour re-visited.

The neurotoxic effect of palmyrah (Borassus flabellifer L.) shoot flour on Wistar rats has been reported previously by Arseculeratne and co-workers. A deficiency in previous studies was an inadequate description of the methodology, especially on the composition and consumption of test and control feed, and weight gain/losses. This study shows that feeds containing 100% and 70% palmyrah flour result in very little or no feed consumption, and deaths reported could have been interpreted as being due to starvation. A mixture of 50% palmyrah flour and 50% standard breeding feed results in the neurotoxic symptoms such as muscle in-coordination, spasms and immobility of hind limbs reported previously (Arseculeratne and coworkers). These neurotoxic symptoms can be eliminated by heating the palmyrah flour at 80 degrees C for 45 min; that is, detoxification. Attempts were made to reproduce the neurotoxic effect by administering two-fold palmyrah flour extractive compared with that contained in the same flour consumed by experimental rats per day. This did not produce a neurotoxic effects (as reported previously while using rats fed on standard breeding feed). It is interpreted that the nutritional status of the diet influences that manifestation of the neurotoxic effect; the effect being suppressed with a nutritious diet. Studies on the blood enzyme levels of rats showed that while alanine aminotransferase was not affected, aspartate aminotransferase was significantly affected by oral administration of organic solvent-free water and methanol:water (1:1) extractives (P = 0.023 and P = 0.0044), respectively. This study shows that while the reported hepatotoxin is not extracted by these solvent systems, there appears to be a tissue non-specific cellular damage reflected at a subclinical level.