The Studies on the Biological Activity of Dioscoreae radix

• Main Authors: Hui-Chuan Huang, 黃慧娟
• Other Authors: Rong-Tsun Wu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/11852635361187085466

碩士 === 國立陽明大學 === 生物藥學研究所 === 91 === Abstract Dioscorea spp., a Dioscoreaceae herbal medicine, has been widely used as a remedy for anti-aging and health promotion. Recent researches indicated that the cell number and plasticity of stem cells had great contribution for aging and age-related disease. In addition, raised morbidity and mortality resulted from infection in the elderly is related with immunosenescence. Therefore, the present research tried to explore whether Dioscorea spp. adiminstration could serve as a immunomodulator and have on effect cell regeneration in order to find out the most important bioactivity of Dioscorea spp. In the aspect of immunomodulation, we examined whether polysaccharide isolated from Dioscorea spp. tubers could enhance protective immunity induced by oral Pneumovax ® 23 vaccine. We tried different adiminstration ways to examine whether Dioscorea polysaccharide could promote systemic and mucosal immunity, which induced Pneumovax ® 23 vaccine — specific serum IgG and mucosal IgA antibody response respectively. We have found that mice were vaccinated by gastric intubation with Pneumovax ® 23 vaccine and supplied with Dioscorea polysaccharides shortly in daily drink could enhance specific antibody response. Stem cells have long been regarded as undifferentiated cell capable of proliferation, self-renewal, production of a large number of differentiated progeny, and regeneration of tissue. Recent reports showing that stem cell fate specification can be controlled by their enviroment. Stem cells also exist in the adult tissues, including, brain, liver, bone marrow and other tissues. Adult stem cells hold great promise for regenerative medicine, tissue repair. This researchtried to examine whether methanol extract of tubers from Dioscorea spp. could enhance stem cells or progenitor cells proliferation, differentiation and regeneration of tissue. We found that, methanol extract of Dioscorea could enhance neuronal progenitor proliferation and differentiation in vitro. This bioactivity may be beneficial to neurogenesis or neuroregeneration. Bone is remodeled continuously during adulthood through the resorption of senescent bone by osteoclasts and the subsequent formation of new bone by osteoblasts. We proved that methanol extract of Dioscorea stimulated proliferation of osteoprogenitor cells and promoted alkaline phosphatase activity, which is a bone formation biological marker of osteoblast. Also, we developed an ovariectomized (OVX) in vivo model to demonstrate the action of methanol extract of Dioscorea in postmenopausal estrogen deficient osteoporosis. Then, The related genes for bone formation and bone resorption were analyed by RT-PCR and histomorphometry. The oral dose of 40 mg/kg/day methanol extracts of Dioscorea could enhance bone formation in ovariectomized mice. Recent papers reported that advanced glycation end - products (AGE) in the body were particularly related with age, diabetes and its complications such as nephropathy, nephropathy or vascular disease. We developed an animal model to demonstrate the action of methanol extrate isolated from Dioscorea in AGE- induced diabetic complications. The strategy was to promote degration and clearance of advanced glycation end - products. Our results showed that methanol extract of Dioscorea could decrease serum level of advanced glycation end - products and prevent kidney and liver from pathological changes. In this study, we demonstrated that Dioscorea polysaccharides did haveimmunomodulatory effects in both systemic and mucosal immunity induced by Pneumovax® 23 vaccine vaccination. Besides, the methanol extrate of Dioscorea not only enhanced bone formation in ovariectomized mice but also stimulated the proliferation and differentiation of progenitor cell in brain and bone marrow. It could also decrease AGE-induced diabetic complications. Our studies suggested that anti-ageing effects of methanol extrate isolated from Dioscorea may mediate by regulating the growth and differentiation of stem cells.