Preventive Effects Of Ethanol Extract Of K. Candel On Rats Model With Insulin Resistance And Rats Model Of Type 2 Diabetes Mellitus

Kandelia candel is a mangrove plant habitating on the shallow salty beaches. It belongs to Genus Kandelia, Rhizophoraceae in taxonomy. And it is the only species of Genus Kandelia.Kandelia candel is about 2-3 meters in height, streches to a large area and forms a formation of Kandelia candel.Kandelia candel is widely distributed and common at the coast of Asian tropical and sub-tropical areas, such as India, Thailand, Vietnam, Malaysia, Japan, etc. In China, it is distributed in bays of Fujian, Guangxi, Guangdong, Hainan, Taiwan and Hongkong. Kandelia candel is used for medication by the folk people. Its bark has the blood-stopping and bacteriostasis effect. The alcohol extract from its roots can be used for the treatment of rheumatoid arthritis. In recently years, the quest for the chemical components and bio-activity of Kandelia candel has been a much-focused research orientation. In 1997, Lu Changyi reported that the seed of Kandelia candel contains organic acid like oxalic acid and malic acid. In 2001, Kimura Kenichiro discovered in the leaves of the Kandelia candel the saturated aliphatic acid, such as palmitic acid, stearic acid, etc and the unsaturated aliphatic acid, such as oleic acid, linoleic acid, etc. To date, from the seeds, leaves, branches and barks of the Kandelia candel, the isolated chemical constituents are mostly polysaccharide, sterols, triterpenoids, flavonoids, alkaloids and tannins.The above constituents have a variety of bio-activities. Take flavonoids for example. It is also called flavone with a multitude of bio-activities, such as bacteriostasis, antiphlogistic, anti-mutagenesis, reducing blood pressure, clearing heat-toxicity, sedative, diuretic, anti-oxidation, anti-tumor, tumor-preventive and lipase inhibiting effects. It is one of the significant natural products. Triterpenoids have the bio-activities of being antiphlogistic, bacteriostasis, anti-tumor, sedative,anti-virus, etc. Plant sterols have the bio-activities of being anti-oxidation, antiphlogistic, to prevent coronary atherosclerosis and to reduce the cholesterol. These chemical constituents are common in most medicinal plants, and are already extracted for the treatment of Cardiovascular System disease, tumor, inflammation and other related diseases. The pharmacological activity of Kandelia candel has been researched a lot in the recent years, the results of which indicate:1. Kandelia candel has the activity of anti-virus. The alcohol extract and water extract of Kandelia candel have the inhibiting effect on three plant fungi:fusarium oxysporum, heminthosporium sp. and semphyllium sp.;The alcohol and water extracts of its roots, leaves, fruits and branches have the bio-acitivity of being in-vitro bacteriostasis and bacteriacidal.2. Anti-gastric ulcer. The water extract of Kandelia candel has the action against waterimmersion - restraint stress and pyloric ligation gastric ulcer.3. The leaves of Kandelia candel have strong antioxidant activity of pigment from kandelia candel leaves.4. The alcohol extract from kandelia candel roots has anti-tumor acitivity. Howerev, nothing has been reported on the anti-diabetic activity of knadelia candel.The polysaccharide and flavonoids have the funciton of reduction of blood glucose. The polysaccharide has the activity of reduction blood glocose. The plants with multi-polysaccharide has the action of anti-diabetics. For example, the Ganoderma Lucidum polysaccharides can reduce the blood glucose in diabetic mice induced by alloxan. In addition, the polysaccharide in angelica sinensis, lycium, pumpkin, shangdang gensing, corn stigma, mulberry leaf and astragali all has the action of reducing blood glucose against experimental animal model of type 2 diabetes mellitus. Flavonoids are major components to reduce blood glucose. They can inhibit lipoperoxide, stabilize the biomembrane and protect the langerhans from being compromised through their anti-oxidation activity. The research shows that the anti-oxidation of quercetin can relieve the damages caused to the langerhan cells by streptozocin, induce the reproduction of langerhans and boost the release of insulin. Flavonoids also have the activity to inhibit a-glucosidase. Such activity may result in the slow digestion of carbohydrate and monosaccharide. So the blood glucose will not increase and achieve the results of blood glucose reduction. What's more, the flavonoids have the funcion of insulin simulation, which will generate the mechanisim of blood glucose reduction by insulin. Exccept polysaccharide, flavonoids, triterpenoids, sterols and tannins have been reported with the function of blood glucose reduction.The bark and leaves of knadelia candel contain rich sources of flavonoids, such as the catechin, rutin, flavan-3-ol, afzelin and epicatechin. The seeds contain pectin and polysaccharide. And the bark contains rich tannins. To explore the knadelia candel has the function of anti-diabetics, the present research extract the knadelia candel branches with alcohol, and establish rat model of type 2 diabetes mellitus by feeding high-fat diets in conjunction with the injection of small-volume of streptozocin. Intervene with preventive administration of alcohol extract of knadelia candel, observe the actions of knadelia candel against rat model of type 2 diabetes mellitus and provide reference for the treatment of diabetics.PartⅠAlcohol extract of knadelia candel branchMethod:The mangrove plant is identified to be knadelia candel. Take 35kg of knadelia candel branch, mill and flux with 95% alcohol and extract. Take the extraction solution and centrifuge. Reduce the pressure and condense, after lyophilization, obtain the dry powder of alcohol extract for the study.Results:The alcohol extraction of knadelia candel is successful. And 3.4kg dry powder of alcohol extract is obtained.PartⅡThe preventative effect of alcohol extract of knadelia candel against rat model resistant to insulin.Objective:Observe the insulin sensitivity, glucose tolerance and influence against blood fat of alcohol extract against rat resistant to insulinMethod:1) Take 72 healthy SD rats, randomly divide them to high dose group of alcohol extract of knadelia candel (2g/kg), intermediate dose group (1g/kg) and low dosage group (0.25g/kg), dimethyldiguanide group (200 mg/kg), model group and normal group. Feed the groups with high fat food for 8 consecutive weeks other than the normal group. From the fifth week on, intervene with gastric perfusion method once a day for 4 consecutive weeks. Administrate 1% sodium carboxyl methyl cellulose in the same amount to the normal group and model group. After four weeks drug intervention, fast for 12 hours and take blood from the venous plexus behind the eye ball. Determine FSG, FINS, compute and get the insulin sensitivity index (ISI) Determine the TC, TG, HDL-C, LDL-C and FFA. Take blood with empty stomach and administrate 25g/kg glucose and take blood after 2 hours for blood glucose level.Results:The high, intermediate and low doses of alcohol extract have significantly reduced FINS, improve glucose tolerance and increase ISI; reduce the levels of TC,TG,LDL-C,FFA. The intermediate dose is the most effective.Conclusion:The alcohol extract of knadelia candel has the function of improving high insulin symptom of rat resistant to insulin and impaired glucose tolerance and increase the insulin sensitivity.PartⅢThe effect of alcohol extract of knadelia candel on indexes for rat model of type 2 diabetes mellitus.Objectives:Observe the effect of alcohol extract of knadelia candel on blood glucose, insulin sensitivity, blood fat, pathology of the pancreas and the anti-oxidation of liver tissues of rat model of type 2 diabetes mellitus.Methods:The rats are fed with high fat food for eight weeks and the test group has been administrated for four weeks to intervene. Based on this, the rats are fast for 12 hours. Inject i.p.0.3%STZ30mg/kg to the rat in the model group and test group and establish rat model of type 2 diabetes mellitus.Inject i.p.0.1 mol/L citrate acid-citrate sodium buffer solution to normal group in the same volume.(2) Fast for 12 hours after 5 days and take blood from the venous plexus behind the eye ball. Determine the levels of FSG, FINS and ISI; Determine the levels of TC, TG, HDL-C, LDL-C, FFA; Kill the rats, and take pancreas out for pathology test; Take the whole liver, weigh and compute the liver index. Take some liver tissues for pathology test and weigh accurately0.2g liver tissue and make into 10%homogenized Liver. Determine the activity of SOD, DAT, GSH-PX and the content of MDA in the liver tissue.Results:The high, intermediate and low dose of alcohol extract of knadelia candel reduced FSG in different degrees and improved ISI; Lowered the level of TG, TC, LDL-C and FFA, and increased the level of HDL-C; Reduced the compromise of STZ toβ-cell and relieved the pancreas pathology change; Prevented the fatty pathological changes of liver tissues, and improve the activity of SOD, CAT, GSH-PX and reduce the content of MDA. The intermediate dose is most effective.Conclusion:The alcohol extract of knadelia candel has the function to reduce the blood glucose, blood fat and protectβ-cell. It may be associated with its ability to improve insulin resistance, and anti-oxidation of liver.