Structure characterisation of polysaccharides in vegetable "okra" and evaluation of hypoglycemic activity.

Okra is a widely accepted vegetable in subtropical and tropical regions due to the good palatability. However, the polysaccharide compositions remain unclear. In this work, the water extract of okra pod was prepared and the leading polysaccharide fraction was purified. The precise structural characteristics were identified. It was a polysaccharide "rhamnogalacturonan" as shown below, and the structure was different to previously reported rhamnogalacturonans. The hypoglycemic effect of rhamnogalacturonan was determined in vivo. By comparing with streptozotocin-induced diabetic mice group, the high-dose group showed decreased blood glucose level and glucose tolerance. The body weight of all groups were not significantly different. The results indicated that the rhamnogalacturonan was responsible for the hypoglycemic effect of okra.