Extraction Of Fern Flavonoids And The Effects On Development Of Atherosclerosis In Cholesterol-fed Rabbits

At present, the most researches about P.aquilinum var.latiusculum focuse on the relationship between P.aquilinum var.latiusculum and ecological environment nutrition analysis,and how to improve the processing and packing technology. Little on Pharmacological activity of the fern flavonoids, rarely in the application of atherosclerosis disease.In this study, based on the single-factor experiment, the extraction technology of flavonoids from Pteridum aquilinum var.latiusculum by orthogonal test with FOSS SoxtecTM 2055 has been optimized, then compared with the direct reflux and Soxhlet reflux, the optimum extraction process has been determined ultimately.In the double-blind, randomized experiment, the model of atherosclerosis has been induced fed a high-cholesterol diet (1%), the effects of all flavonoids of P.aquilinum var.latiusculum has been investigated on the development of atherosclerosis.Eighty japanese rabbits are divided into five groups:normal group(fed a basial diet), AS control group(fed 1%cholesterol), flavonoids I group(fed a high-cholesterol diet with 20mg/kg.day all flavonoids from P.aquilinum var.latiusculum), flavonoids II group (fed a high-cholesterol diet with 40mg/kg.day all flavonoids from P.aquilinum var.latiusculum), simvastatin group(a high-cholesterol diet with 2.5mg/kg.day simvastatin). At the end of the experimental period, the biochemical indexes of serum in all groups have been determined,including TC,TQHDL-C,LDL-C,GLU,ATP,ALP,CK,NO,OX-LDL, and atherosclerosis index has been calculated. After sacrificing the rabbits, the weight of the organs have been weighed, and the aortic arches have been removed,some have been stained with Sudan III to evaluate the intimal lipid lesion quantitatively,others have been used for HE staining to examine the histopathological changes,as well as liver lesion,the thickening of intima and media are measured and the ratio between intima and media have been calculated.The results show that the yield obtained by FOSS SoxtecTM2055 is much higher than the direct reflux and Soxhlet reflux, is 2.78 times of the direct reflux and 2.25 times of Soxhlet reflux., therefore, the optimal extraction technology of total flavonoids from bracken fern is as follows:60% volume fraction of ethanol solution,2 h boiling time,1 h leaching time and 1:30 solid-liquid ratio, and the yield is 8.8%, under this condition. The weight of body and mental state in the treatment group of fern flavonoids are better than AS control group, and the levels of serum TC,TG,LDL-C,AI,ALT,OX-LDL are significantly lowered (P＜0.05),compared with AS control group, while the levels of NO,CK are significantly increased (P＜0.05) and no significant changes are found in glucose level (P>0.05). The atherosclerotic lesion of the treatment group of fern flavonoids is reduced significantly, furthermore the lesion area of the higher dose group reduced 53.3%, compared to AS control group. In the treatment group of fern flavonoids there is a more thickening of tunica intima compared to AS control group.Morphological changes of rabbit aorta is improved in the treatment group of fern flavonoids.Worth mentioning, the higher-dose group has the same effect as simvastatin.The results of the present study demonstrate the optimal extraction technology improves greatly the efficiency of the yield of all flavonoids from P.aquilinum var.latiusculum, furthermore, flavonoids of P.aquilinum var.latiusculum show a promising effect in its inhibition process of atherosclerosis, relevant to its lipid lowering activity and antioxidant activity.Thus, flavonoids of P.aquilinum var.latiusculum may be used effectively for the prevention and treatment of atherosclerosis.