Preliminary Study On Chemical Compositions Of Stephania Yunnanensis. Lo And Structrure-antiarrhythmic Activity Relationship Of Aporphine Type Alkaloids

Stephania yunnanensis. Lo is a plant of Stephanie Lour Subgen. Tuberiphania.Most species of this Subgen are medicinal plants which possess activities ofantipyretic, analgesic, anti-bacterial, anti-inflammatory, antiarrhythmic andantitumor, etc. In flora of China, Subgen. Tuberiphania was divided into twosections: Sect. Tanscostula Lo et Yang and Sect. Tuberiphania Lo et Yang. Speciesof Subgen. Tuberiphania contain abundant alkaloids, in which Aporphine andProtoberberine types were dominants groups.In order to explore the structrure-antiarrhythmic activity relationship ofaporphine type alkaloids and discovery antiarrhythmic lead compound, this thesisinvestigated the chemical composition of Stephania yunnanensis. Then lays outresearch on acute toxicity and antiarrhythmic activities of three aporphine typealkaloids attained (Crebanine; Dicentrine and Isocorydine) by experiments onarrhythmic rat caused by BaCl2. Finally, this thesis try to discuss thestructrure-antiarrhythmic activity relationship of acquired aporphine type alkaloidson the basis of the chemical and pharmacological research. The main contents are asfollows:1. Study on chemical compositions of S. yunnanensisAlkaloids from S. yunnanensis was extracted with95%ethanol under reflux.Extracts were dissolved in acid and extracted with chloroform. Then total alkaloidwas obtained by acid solution and alkali precipitation. By means of isolationmethods such as column chromatography, gel chromatography and analyticaltechniques including UV spectrum, MS, NMR, etc, totally seven compounds wereobtained and determined as: Aporphine type involved Crebanine, Dicentrine, Isocorydine and Stephanine; Morphine type involved Sinoacutine; Protoberberinetype involved Stepharanine and Jatrorrhizine.2. Comparision of acute toxicity and antiarrhythmic activities of threeaporphine type alkaloidsFive alkaloids attained including Crebanine, Dicentrine, Isocorydine,Stephanine and Sinoacutine were tested on ventricular fibrillation(VF) mice modelinduced by chloroform, and Crebanine, Dicentrine, Isocorydine and Sinoacutinewere found to exhibit significant activity to VF (P<0.05). Then acute toxicity tests ofCrebanine, Dicentrine and Isocorydine were conducted on mice to gain the dosagethat cause0%death (Dn) and100%death (Dm), LD50were calculated by Blissmethod to determine the safe dose accordingly. Result shoued that LD50ofCrebanine was9.382mg/kg; LD50of Dicentrine was26.802mg/kg; LD50ofIsocorydine was32.167mg/kg respectively. Crebanine toxicity is the largest.According to the LD50, the dosage of three aporphine type alkaloids wereconvered into three groups-high dosage, medium dosage and low dosage to conductantiarrhythmic tests on rat arrhythmic model induced by BaCl2. BL-organismfunction experiment system was adapted to observe and record the rats numbers andtimes of resuming normal sinus rhythm and numbers of rat that lasted sinus rhythmfor over20min after administration. The result showed that compared with the NSgroup, the rats numbers and times of resuming normal sinus rhythm of3dosesgroups of Crebanine-high dose(5mg/kg), medium dose(2.5mg/kg) and low dose(1.25mg/kg); three doses groups of Dicentrine and Isocorydine-high dose(10mg/kg), medium dose (5mg/kg) and low dose (2.5mg/kg) were obviouslyincreased (P<0.05or P<0.01). Numbers of rat that lasted sinus rhythm for over20min of three dosage groups of Isocorydine and high dosage of Crebanine andDicentrine were remarkably higher than that of the NS group (P<0.01)；Whichindicated that Crebanine, Dicentrine and Isocorydine all had significantantiarrhythmic activity. And the activity of Crebanine inclined to be higher thanDicentrine and Isocorydine.3. Discussion of the structure-antiarrhythmic activity relationship ofCrebanine, Dicentrine and IsocorydineThe planar structure, stereo structure, acute toxicities and antiarrhythmicactivities of three aporphine type alkaloids-Crebanine, Dicentrine and Isocorydine were analyzed and try to find, if possible, the functional groups that may haveinfluce on the toxicities and activities. Results suggested that in the three aporphinetype alkaloids, dioxymethyl on the C-1，C-2of A ring is the main cause for theiracute toxicities possiblly, while methoxyl on the C-8of D-ring could add to theiracute toxicities and activities than that on the C-10, which may be owed to theimpact of these functional groups on their polarity.