[Antitumor effect of polysaccharides from cactus pear fruit in S180-bearing mice]

Polysaccharide components of some traditional Chinese medicine have certain antitumor effects and can promote immune responses. Extractions from cactus pear fruit can inhibit the proliferation of cervical cancer, ovary cancer and bladder cancer cells, and suppress the growth of ovarian cancer in mice. This study was to observe the antitumor effect of polysaccharides extracted from cactus pear fruit in S180-bearing mice.

S180-bearing mice were established and divided into five groups: normal saline (NS) group, cyclophosphamide (CTX) group, high, middle and low dose of polysaccharide groups. Tumor inhibition rates, values of thymus index, spleen index, superoxide dismutase (SOD), maleic dialdehyde (MDA) and nitrogen monoxidum (NO) were recorded. Changes in ultra-structures of tumor cells under transmission electron microscopy were observed.

The tumor inhibition rates in CTX group, high, middle and low dose groups were 7.78%, 31.13%%, 49.70%, 61.07%, respectively. The thymus index was significantly higher in middle and high dose groups than in NS group [(2.61+/-0.43) mg x g(-1) and (2.65+/-0.73) mg x g(-1) vs. (2.22+/-0.24) mg x g(-1), P<0.05]. The spleen index of high dose group was higher than that of NS group [(6.45+/-0.97) mg x g(-1) vs. (5.42+/-1.13) mg x g(-1),P<0.05]. SOD of middle and high dose groups [(303.12+/-13.03) U/mL and (310.03+/-18.02) U/mL] were higher than that of NS group [(280.12+/-10.01) U/mL](P<0.05). MDA was lower in low, middle and high dose groups [(6.56+/-0.75) nmol/mL, (6.24+/-1.03) nmol/mL and (5.78+/-0.90) nmol/mL, respectively] than that in NS group [(7.39+/-0.51) nmol/mL] (P<0.05). NO was lower in low, middle and high dose groups [(56.12+/-8.60) micromol/L, (50.12+/-10.05) micromol/L, (48.06+/-8.45) micromol/L respectively] than in NS group [(64.14+/-1.25) micromol/L](P<0.05). Under electron microscopy, polysaccharide or CTX treated tumor cells showed typical morphology of early apoptosis with condensed chromatin at the margins of nuclei, disintegrated nucleolus and vacuoles in the cytoplasm.

Polysaccharides extracted from cactus pear fruit possess certain antitumor effects, which can induce apoptosis, increase antioxidation and promote immune responses.