The Poisonous Components And Common Mechanism Of Detoxification Processing Of Araceae Herbal Medicine

This project was supported "Eleven-Five" national projects of technological supporting (No.2006BAI09B06-10) and national natural science foundation(No.30772785).Pinellia ternate(Thunb.)Breit.,Arisaema amurense Maxim.and Typhonium giganteum Engl., included in Chinese Pharmacopoeia(2005),are all belonged to Araceae family.And Pinellia pedatisecta Schott is widely used in china herbal market as a substitute for arisaematis.The property and flavor of the four Araceae plants is all documented to be 'acrid,warm and toxic'. That means these crude drugs have intensive acridity and toxicity,causing swelling of the lips, mouth and throat,aphonia,salivation,convulsion,convulsion,and even death from suffocation. So clinical medication is that they are all processed with Potash Alum through duplicating method.Whether the four plants have the same acridity component? Whether the same detoxification processing mechanism present in the common processing method? No report.At the base of our group work on the acridity factor and the processing detoxification mechanism of Pinellia ternate(Thunb.)Breit.,in this paper,we attempt to prove the conjecture.The work as follows:1 Common poisonous component in the four types of Araceae herbal medicine.Using different polarity solvent extraction and separation,different polar solvent extracts were obtained respectively from the four plants.At the same time,the seperation of the calcium oxalate raphides was achieved by centrifugalization.The common poisonous component of the four plants(Araceae) were identified through toxicity screening,rabbits' conjunctival irritation experiment as the animal model.The needle-like raphides of calcium oxalate were proved to be their common poisonous components,which were named as 'poisonous raphides'.2 The comparison of the irritant and toxic intensity of the four crude drugs and the dose-toxic response relationships of the poisonous raphides.The irritant and toxic intensity of the four crude drugs(Araceae) and the raphides inside of them was detected through mice acute toxicity experiment and the rabbits' eye irritation experiments,and the result showed the level as follows:Pinellia pedatisecta＞Pinellia ternate＞ Arisaema amurense＞Typhonium giganteum.The action mode of acrid raphides on mucous membranes was investigated through mice mesentery experiment,after intraperitoneal injection with the power pf the four crude drugs.The rusults showed that the poisonous raphids punctured into the cell of the mesenteric tissue directly.Futhur study about the toxic and irritant intensity and the dose-toxic response relationships of poisonous raphides indicated that toxicity enhanced with the increase in concentration of poisonous raphides.The toxicity presented linear doseresponse relationships during a range in concentration.The result further indicated that the raphides were their common poisonous factor.3 Analysis of poisonous raphides in the four types of Araceae herbal medicine.Through determination of raphides content in the four crude drugs,the content level showed as follows:Pinellia pedatisecta＞Pinellia ternate＞Arisaema amurense＞Typhonium giganteum. The raphides content level was in line with level of the toxic intensity of the four crude drugs. This consistency further indicated that the poisonous raphides were their common poisonous components.Their morphology was studied by light microscope and Scanning electron microscopy(SEM).The raphides of the four plants all have two types of raphides(long and short).SEM of the raphids showed pointed and blunt ends of a raphide,and a long groove and barbs on it.The result of X-ray diffraction,photoelectric spectra and infrared spectra showed the raphides consist of calcium oxalate monohydrate and-NH,-COOH and -S- functional groups. Results of identification and composition analysis showed that the four plants poisonous raphides all consist of calcium oxalate,proteins and small amount of Polysaccharide (Glycoprotein).SDS-gel electrophoresis separation of raphides proteins results indicated that the major protein bands are basically the same,showing the same bands of 26KD and 51KD The proteins isolated from raphides in the four plants had strong acridity,and allergenicity.Through determination,the content level of the protein in the raphides is as follows:Pinellia pedatisecta＞Pinellia ternate＞Arisaema amurense＞Typhonium giganteum.The content level was also in line with the level of intensity of the toxicity,which indicated that the toxicity derived from not only the blunt structure of the raphides but also from protein.4 Common mechanism of detoxification processing of the four types of Araceae herbal medicine.The common mechanism detoxification processing with Potash Alum was studied by analyzing the constituents of the raphides in alaum water solution system.Al³⁺ in alaum water solution have the combination ability with C₂O₄^2- which comes from calcium oxalate raphides, which made the raphides decompose.At the same time,the alaum water solution is acidic,and the raphides proteins were hydrolyzed,which completely destroyed the raphides structure and crystal form.Irritation and toxicity,decreased.The results as above showed that:the toxic components of the four types of herbal medicine (Araceae) belong to one class of toxic components.That is piosonous raphides,having a special crystal structure,needle-like crystal,with calcium oxalate,proteins as the main conponents.The toxicity mainly due to the dual effects of mechanical stimulation of special crystal form and chemical stimulation of protein allergens.The level of toxic and irritant intensity was in line with the level of the raphides concentration of the four crude drugs:Pinellia pedatisecta＞Pinellia ternate＞Arisaema amurense＞Typhonium giganteum.The common mechanism of detoxification processing with Potash Alum was that Al³⁺ in alaum water solution combined with C₂O₄^2-,which cause the decomposition of calcium oxalate,and the rigid support of crystal is damaged,while the alaum acidic water system also made proteins hydrolyzed,and the entire crystal structure was damaged.The toxicity disappearedTo sum up,the piosonous raphides were the common poisonous factor in Pinellia ternate(Thunb.)Breit,Pinellia pedatisecta Schott,Arisaema amurense Maxim and Typhonium giganteum Engl.The common detoxification mechanism present in the processing methods.