RESUMO
Osteoporosis （OP） and osteoarthritis （OA） are common bone diseases in clinic. OP is a systemic skeletal disease， and OA is a chronic degenerative joint disease with high prevalence and disability rates. With the advent of the aging population， the incidence rate of OA and OP is increasing year by year， and they have become common diseases of the elderly. The quality of life and physical and mental health of patients are severely affected by the above two bone diseases. Chinese medicine has a long history of treating bone diseases， with a good clinical effect on preventing and treating OP， OA， and other bone diseases with few side effects. It is one of the commonly used methods to treat bone diseases. Polysaccharides， as one of the active substances of Chinese medicine， have various pharmacological activities and a wide range of sources with low toxicity， and their effect cannot be ignored. The role of polysaccharides in the treatment of bone diseases has been deeply studied. It has been found that the mechanism of Chinese medicine polysaccharides in treating OP and OA involves multiple levels， targets， and pathways. Through the analysis and summary of the relevant literature on the mechanism of Chinese medicine polysaccharides in treating OP and OA， it was found that Chinese medicine polysaccharides mainly treated OP by regulating the bone dynamic balance between osteoblasts and osteoclasts and affecting bone marrow mesenchymal stem cells and bone microstructure. The mechanism of Chinese medicine polysaccharides in the treatment of OA is related to the regulation of chondrocyte growth， the increase in the proteoglycan and collagen content in the cartilage matrix， and the reduction of oxygen free radical content and inflammatory mediator level. This study aimed to further explore the internal relationship among mechanisms of Chinese medicine polysaccharides in the treatment of bone diseases， to provide relevant ideas for the study of Chinese medicine polysaccharides in the treatment of bone diseases.
RESUMO
OBJECTIVE：To optim ize the water extraction-ethanol precipitation technology of polysaccharide from Litchi chinensis seed，and to evaluate its hypoglycemic activity in vitro . METHODS ：The content of polysaccharides was determined by phenol-sulfuric acid colorimetry ，and the extraction rate of polysaccharides was calculated. Single factor test and response surface methodology were used to optimize the water extraction technology with the ratio of material to liquid ，extraction times and extraction time as factors ，and the extraction rate of polysaccharide as index. Single factor test was used to screen the concentration volume fraction of water extract and ethanol precipitation Using acarbose as contro l，4-nitrophenol-α-D-glucopyranoside method was used to investigate in vitro inhibitory activity of polysaccharide from L. chinensis seed to α-glucosidase. RESULTS ：The optimal technology was the ratio of material to liquid 1∶19 （g/mL），decocting for 3 times，1 h for each time ，concentrating the water extract to 40％ of original volume ，and adding ethanol to 80％ volume fraction. After deproteinization by Sevage method ，the crude polysaccharide of L. chinensis seed was obtained. The results of 3 times of validation tests showed that ，extraction rates of polysaccharide were 7.61％，7.89％，7.99％，average extraction rate was 7.83％（RSD＝2.52％，n＝3）. The contents of polysaccharide were 55.57％，55.83％ and 56.66％，average content was 56.02％（RSD＝1.81％，n＝3）. The inhibitory activity of the polysaccharide from L. chinensis seed to α-glucosidase were increased as concentration ；its IC 50 was 0.056 mg/mL，which was lower than positive control acarbose （0.196 mg/mL）. CONCLUSIONS：The optimal water extraction-ethanol precipitation technology of polysaccharide from L. chinensis seed is stable and feasible. The polysaccharide from L. chinensis seed show significant in vitro inhibitory effect on α-glucosidase，which is better than that of acarbose.
