Studies On Active Components From Cornus Officinalis Sieb.et Zucc. In The Treatment Of Diabetes And Its Complications

Diabetes mellitus (DM) is a metabolic disorder in the endocrine system. The disease is found in all parts of the world and is rapidly increasing in most parts of the world. The population among adults is about3%and will reach to7.7%by2030in the word. Along with the development of DM, continuous high blood glucose can cause many serious complications and is the leading cause of death in patients with diabetes. Up to now, many kinds of anti-diabetic medicines have been developed for patients, but almost all are chemical or biochemical agents. Excepting high cost, many hypoglycemic agents have serious adverse effcts. The fact is that it has never been reported that someone had recovered totally from diabetes. The traditional Chinese medicine demonstrated a good practice and shows a bright future in the therapy of diabetes and its complications because of distinctive traditional medical theory and Chinese medicines. Cornus officinalis Sieb. et Zucc., a commonly used traditional Chinese medicine, as a food and medicine has been used for at least2,000years in China to exhibit several biological activities. In recent years, modern pharmacological studies have revealed that its extract and preparations exhibited many biological activities including hypoglycemic, antineoplastic, and antimicrobial effects, and to improve liver and kidney functions. The objective of this study are to explore the active components from edible Chinese herbal Cornus officinalis Sied.et Zucc. in the treatment of diabetes and its complications. Extraction and purification active components from Cornus officinalis according to the activities of antihyperglycemic and antioxidantion. The experiments based on HepG2cells, a-glycosidase and STZ-induced diabetic mice was carried out, in order to research and evaluate the effect in treating diabetes mellitus and its complications of Cornus officinalis The main content was summarized as follows: 1. Fractions with a different polarity from Cornus officinalis were prepared by solvent extraction and evaluated the anti-diabetic potentials by glucose uptake and reactive oxygen species generation in HepG2cells. Acetic ether fraction (Fr.2) and the n-buthanol fraction (Fr.3) had the highest ability to enhance glucose uptake and to inhibit ROS generation, Fr.3was further fractionated with D101macroporous resin column and then eluted with EtOH-H2O at0:100(Fr.3-1),30:70(Fr.3-2),60:40(Fr.3-3) and90:10(Fr.3-4). Sequentially, The Fr.2was subjected to column chromatography over silica gel eluted with CHCl3-MeOH (50:1to10:1) to get ursolic acid (UA). The Fr.3-2was subjected to a series of chromatographic silica gel column (CHCl3-CH3OH) and Sephadex LH-20column (CHCl3-CH3OH) chromagrafhy to yield loganin and morroniside.2. The α-glycosidase was used to analysis the inhibition of α-glycosidase activity. HepG2cells were used to evaluate the ability of fractions to enhance glucose uptake. In vitro α-glycosidase inhabitation test, the ethyl acetate extract (Fr.2) and n-butanol extract (Fr.3-2) showed weak activity and IC50(mg/ml) values were2.40±0.35and4.24±0.78respectively. Loganin, morroniside and ursolic acid (UA) showed no effect on α-glycosidase. As shown in test in HepG2cells, the glucose uptakes in HepG2cells mediated by Fr.2and Fr.3were obviously higher than other fractions, And then, the loganin and mrroniside that separated from Fr.3-2and the UA that isolated from Fr.2mediated a dramaticlly higher glucose uptake in HepG2cells than their startings, respectively.3. In vitro antioxidant activity test, cellular assay were carried out to evaluate antioxidant activity of different fractions. HepG2cells-based assay showed that the values of antioxidant activity boosted by UA, loganin and morroniside.4. In long-term therapy test (4weeks) in STZ-induced diabetic mice, Acetic ether fraction Fr.2and Fr.3-2had positive effect in treat STZ-induced diabetic mice. Compared with the diabetic control group, groups were given UA, loganin and morroniside to increase superoxide dismutase (SOD) activity and decrease malodialdehyde (MDA) level in mice plasma. Meanwhile, they inhibited aldose reductase (AR) and ameliorated kidney damage in diabetic mice. They had lower plasma glucose. Cornus officinalis, especially the ecetic ether fraction and Fr.3-2fraction showed the ability of treating diabetes and its complications by prevent the decrease in SOD activity and suppress the increase of MDA. Body weight, food and water intake, kidney/body weight were measured too.