Antioxidant effect of Tryptophan on biochemical parameters in the haemolymph and fat body of final instar larvae of silk insect, Bombyx mori

Abstract

Ageing is a natural life process whose manifestations are familiar and unambiguous. Oxidative modification of cellular molecules by reactive oxygen species and impaired antioxidant mechanism play unique role in a variety of age-associated degenerations. As a defence, cells have developed antioxidant defence system of a group of enzymes including catalases and peroxidase destroying toxic molecules. The natural antioxidant mechanism of an organism may be insufficient and external dietary administration of anti oxidant compounds play vital role in defence against ageing. In the present study, the antioxidant effects of reducing amino acid tryptophan in the final instar larvae of silkworm, Bombyx mori. The turnover of total protein, amino acid and glucose was evaluated. The total haemolymph protein of treated larvae showed 34-94% increase when compared to normal and the pattern of the changes in the levels of fat body protein was same but with a change of 12 fold. The total content of free amino acids in the haemolymph of normal and treated larvae increased gradually from the period of 0 h to 96 h with a peak value at 96 h and then decreased. The total content of free amino acids in the fat body is much less than that found in the haemolymph. The peak glucose levels in the total larval haemolymph were almost 28 times to that found at the early stage in normal larvae and approximately 12 times in tryptophan treated larvae. The fat body glucose level showed a consistent reduction in the treated larvae.