Effect of ultrasonic treatment on the degradation and inhibition cancer cell lines of polysaccharides from Porphyra yezoensis.

The exposure of polysaccharides solutions to high-energy ultrasound produces a permanent reduction in viscosity and change in activity. However, the exact mechanism which occurs in the process is still not clear. In this work, degradation of polysaccharides from Porphyra yezoensis (PP) was indirectly and directly judged by intrinsic viscosity and high performance gel permeation chromatography. The degradation process was established with dynamics and affirmed by theoretical derivation. Inhibition of cancer cell lines (SGC-7901, 95D) was also investigated by assays of tetrazolium colorimetric. The intrinsic viscosity of the degraded PP decreased exponentially with increase in ultrasonic time, and theoretical derivation was established and confirmed well. The distribution and new fraction of degraded polysaccharides was found. Ultrasound degraded preferentially large PP molecules and cleavage took place roughly at the centre of the molecules. During ultrasound degradation the molecular weight distribution was narrowed. The inhibition activities of SGC7901 with ultrasound degraded polysaccharides were increased.