| Rhododendron mariesii.is the dry leaf of Rhododendron dauricum L.It has antibacterial,cough relieving and antioxidant effects,and is often used in the treatment of acute and chronic bronchitis and bronchial asthma.Researchers have found that flavonoids hyperin,quercetin and farrerol have antibacterial and antitussive effects and can be used in the treatment of bronchitis.Bronchitis and bronchial asthma are nonspecific inflammation of tissues and mucosa around the trachea caused by Escherichia coli,Pseudomonas aeruginosa infection and tracheal smooth muscle spasm.In order to explore the optimal extraction conditions,antibacterial activity and tracheal smooth muscle relaxation mechanism of hyperin,quercetin and farrerol in Rhododendron mariesii.,the extraction process,antibacterial activity and tracheal smooth muscle relaxation activity of three main flavonoids(hyperin,quercetin and farrerol)in Rhododendron mariesii.were studied in this study.The main research contents are:1.The contents of hyperin,quercetin and farrerol were determined by high performance liquid chromatography(HPLC)and the methods were investigated.The HPLC method established in this study had good results,and the linear relationship between the three components was good in the range of 2.00-80.00 μg/m L.The average recoveries were 100.32% of hyperin(RSD = 2.63%),102.71% of quercetin(RSD = 2.89%)and 102.12% of farrerol(RSD = 2.36%).The method could be used for the determination of three components in Rhododendron mariesii.2.The flavonoids were extracted by ultrasonic cell crushing extraction method.The optimal extraction parameters were predicted by response surface optimization experiment design as extraction power of 90 k Hz,extraction time of 35 min and solid-liquid ratio of 1:25 g/m L.Three verification experiments were conducted under these conditions.The results showed that the extraction amounts of hyperin,quercetin and farrerol were 1.58 ± 0.11 mg/g,1.81 ± 0.15 mg/g and 1.77 ± 0.13 mg/g,respectively,which were not significantly different from the expected results in the model,indicating that the extraction process parameters were reliable and could be used for the extraction of three main components of Rhododendron mariesii..Compared with microwave-assisted extraction,ultrasonic cell crushing extraction method has the advantages of low extraction temperature,less energy consumption and high extraction rate.3.The bacteriostatic activities of the extracts of Rhododendron mariesii.,hyperin,quercetin and farrerol against Escherichia coli and Pseudomonas aeruginosa were studied.The results showed that the extract,quercetin and farrerol have good bacteriostatic ability.The MIC values against Escherichia coli were0.01,0.31 and 0.04 mg/m L,respectively.MIC values for Pseudomonas aeruginosa were 1.56,1.25 and 0.08mg/m L,and MBC values for Escherichia coli were 0.02,0.63 and 0.08 mg/m L,respectively.The MBC values of Pseudomonas aeruginosa were 3.10,2.50 and 0.16 mg/m L,respectively.The cell samples treated with Rhododendron mariesii.extract,quercetin and farrerol showed logarithmic delay and severe morphological damage.The inhibitory effect of hyperin on Escherichia coli and Pseudomonas aeruginosa was not obvious.4.The diastolic effect of the extract and its three main components on tracheal ring in rats was studied by in vitro gas tube perfusion.Preincubation was performed with chlorpheniramine,indomethacin(Indo),glibenclamide(Gli),L-nitroarginine methyl ester(L-NAME),nifedipine,and propranolol,and the changes of tracheal smooth muscle tension were observed and calculated.The results showed that the diastolic effects of the extracts of Rhododendron mariesii.and hyperin in the tissues incubated with chlorpheniramine,LNAME and nifedipine were significantly different from those in the unincubated tissues,and the diastolic effects were decreased,which may be achieved by inhibiting histamine H1 receptor,nitric oxide synthase pathway and calcium ion channel mediated calcium ion flow. |
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