Research On The Technical Literature Of Decoction Of Traditional Chinese Medicine

With confirmed efficacy decoction is a dosage form that can best reflect the TCM holistic theory and the characteristics of TCM diagnostics and therapeutics.Today,this dosage form is still be used widely in TCM clinical practice.Concerning preparing decoctions used in traditional Chinese medicine(TCM),Xu Dachun,a famous TCM practitioner of Qing Dynasty,once said in his book Yixueyuanliulun(医学源流论),"Great attention must be paid to the method for preparing decoctions,because it determines the effectiveness of a decoction.”The thesis use the methods of literature,go through the ancient medical classics,typical classics,specialized classics,pharmacy classics and modern literature,summarize and analyze vessels for boiling decoction,soaking of decoction before boiling,amount of water used for boiling decoction,heat intensity for boiling decoction,amount of time for boiling decoction,number of time for boiling decoction and special procedures for preparing decoctions.In order to offer ideas on assuring the quality and curative effect of decoctions,improving the rationality of TCM drug administration in clinical practice and promoting the construction of TCM clinical pharmacology,the author of this master’s thesis made some suggestions on the standardization of the method used today for preparing decoctions.This master’s thesis consists of the following 7 sections.1 Vessels for Boiling Decoction IngredientsThe working efficiencies of various vessels for boiling decoction ingredients,such as marmite,porcelain pot,red stoneware pot,glassware,enamelware,stainless steel kettle,silverware,copper pot,iron pot,aluminum pot,stoneware,cheng-zi an ancient decoction-preparing instrument),diao-zi(铫子)an ancient decoction-preparing instrument),electric decoction-preparing pot and decoction-preparing machine,were assessed,and the influences of these vessels on the ingredients of a decoction were investigated.According to the results,the following vessels can be used for boiling:marmite,porcelain pot,red stoneware pot,enamelware,glassware,electric decocting pot and decoction-preparing machine.But some vessels,such as iron pot,aluminum pot,copper pot and aluminum pot,are not good for boiling decoction ingredients and cautions should be taken when using them.In addition,the author refer to ancient vessels—cheng-zi and diao-zi,the former is good for slowly heating decoction liquid and the latter works much like the marmite and shows a good effect for preserving heat.2 Soaking of Decoction Ingredients before BoilingConcerning soaking decoction ingredients,a reasonable soaking procedure consisting of the amount of water for soaking,manners of soaking and the amount of time for soaking was put forward by the author of the master’s thesis.As far as the amount of water for soaking is concerned,generally speaking,the surface of the water used for soaking should be over that of decoction ingredients for 2-3 cm in a decoction-preparing vessel.However,less water should be used for soaking the ingredients of hard texture,and more water,for the ingredients of loose texture.As far as the manners of soaking are concerned,the regular decoction ingredients should be soaked in water in a covered container,but those ingredients with the effect of dispersing pathogenic evils residing in between the interior and exterior of the body and of balancing cold and heat should be soaked in water in an uncovered container.Cold water(at room temperature)is used in the soaking procedure.As far as the soaking time is concerned,the ancients soaked drugs have half day,a night or three nights.Today,decoction ingredients should be soaked in water for about 30 min in spring and summer,and for about 1 h in autumn and winter according to the present practice.So the author suggests that decoction ingredients should be soaked in water for over 4 h in order to increase their utilization rate.On the contrary,It should be reminded that overtime soaking may decompose decoction ingredients.Soaking time should be considered with texture and season,generally speaking,flowers,stems and entire plants should be soaked shorter,roots,rootstalks,seeds and fruits should be soaked longer.In autumn and winter,herbs should be soaked longer,in spring and summer,herbs should be soaked shorter.3 Amount of Water Used for Boiling Decoction IngredientsOn the basis of the results of a study on the amounts of water used for boiling decoction ingredients recorded in several medical classics,such as Shanghanlun(伤寒论),Jinguiyaolue(金匮要略),Qianjinfang(千金方),Waikezhengzong(外科正宗)and(太平惠民和剂局方)and so on,the author of this master’s thesis suggests that the amount of water(mL)used for boiling decoction ingredients should be 6-8 times the amount of the ingredients(g),which can be adjusted according to the amount of drug,the extent of water absorption and amount of time for boiling.If there are more hydrophilic herbs,then more water should be used,if there are more hydrophobic herbs,then less water should be used.Besides,the amount of time for boiling drugs for relieving exterior syndrome is shorter but nourishing herb is longer,so less water can be used for former but more water for later.The author also studied the amounts of water used for boiling the surgical disease-treating decoction ingredients and the roughly-powdered decoction ingredients.And based on the results from this study,the author suggests that the amount of water used for boiling the former should be 13 times the amount of ingredients,and for the latter,20 times.The reason why larger amounts of water are used for boiling these two kinds of decoction ingredients is that the decoctions for treating surgical diseases need to be in a low concentration so as to exert an ascending effect and the roughly-powdered decoction ingredients are liable to stick to the vessel used for preparing the decoction.At present,in the field of pharmacy,it can be found that sometimes the amount of water used for boiling decoction ingredients is calculated by using 2 formulas,namely,A=γG+βt+αand B=βt+a,in which A=the amount of water used for the first boiling,B=the amount of water used for the second boiling,y=absorption-accumulation coefficient,G=weight of decoction ingredients,β=evaporation coefficient,t=boiling time,and α=expected amount of decoction liquid.The thesis show that the amounts of water used for boiling decoction ingredients is the conclusion of clinical experience,it should be attached importance.4 Heat Intensity for Boiling Decoction IngredientsThe author of the master’s thesis studied the heat intensity adopted in boiling decoction ingredients and found that at present,in most decoction-preparing practices,high heat is used to heat decoction ingredients to boiling at first and then,the heat is immediately adjusted to a low intensity for heating decoction ingredients slowly.Influences of low heat and high heat on the pharmacological properties of decoction ingredients were studied by the author of the master’s thesis and the decoction ingredients which should be boiled at low heat and those which should be boiled at high heat were summarized.The decoction ingredients which should be boiled at high heat include(1)those which are used for preparing a fast-concentrated decoction or a decoction for treating critical diseases;(2)those which contain volatile components,and those which contain components that can be extracted easily;(3)those which are used for treating upper-jiao diseases,and those which are expected to exert their ascending and outward effect.The decoction ingredients should be boiled at low heat include(1)those which exert tonifying effect.Such decoction ingredients should be heated by using high heat to boiling at first and then,to be heated by using low heat slowly in order to thoroughly extract their tonifying components;(2)those which are originated from minerals,animals and shellfish,those which contain the components that are difficult to be extracted;and(3)those which are used for treating lower-jiao diseases,lower limbs and purtenance.5 Amount of Time for Boiling Decoction IngredientsThe amount of time for boiling decoction ingredients can be expressed as absolute boiling time and relative boiling time.Measured by using hours or minutes,the value of the absolute boiling time can be different if the intensity of the heat used for boiling decoction ingredients is different,although the decoction ingredients are boiled in same amount of water and same time,so,absolute boiling time is easy to grasp but may affect the quality of decoction.Different from the absolute boiling time,the relative boiling time can be calculated by many methods,such as(1)water consumption method,(2)boiling frequency method,(3)indicator method and(4)odor emission method.The author of the master’s thesis holds that the water consumption method is scientific.It can be used to control the amount of time for boiling decoction ingredients by those patients who would like to have their decoctions prepared by themselves.An example of the water consumption method is the note on preparing Guizhi Decoction in the medical classic Shanghanlun(伤寒论),which goes like this:"Add 7 sheng of water into the pot and get 3 sheng of decoction liquid when the boiling is finished." It can be known from this example that the volume of decoction liquid is equivalent to about 43%of that of the water used for boiling the decoction ingredients.The author suggests that heating should be stopped when the volume of the decoction liquid is equivalent to 30%-50%of that of the water used for boiling most decoction ingredients.For boiling the decoction ingredients which possess a descending effect or those which are used for treating lower-jiao diseases or tonic medicine,heating should be stopped when the volume of the decoction liquid is equivalent to 10一29%of that of the water used for the boiling and,for boiling those which are used to treating upper-jiao diseases,disperse eczema,the decoction that use honey as solvent and divergent medicine heating should be stopped when the decoction liquid is equivalent to 51%-75%of that of the water for boiling.6 Number of Time for Boiling Decoction IngredientsThe author of the master’s thesis investigated the number of time for boiling decoction ingredients and the results show that the ingredients of a decoction under preparation is boiled mostly for only 1 time before the Song Dynasty.At present,however,the ingredients of a regular decoction are boiled for 2 times,and that of a tonifying decoction or hard texture,for 3 times.The author also made a summarization of the several supplementary means for preparing decoctions,such as(1)filtrating and concentrating,which is used for preparing decoctions with the effect of harmonizing the function and activity of the exterior-interior and the ascending-descending control centers of the human body;(2)separately boiling and concentrating together,which is used for preparing decoctions consisting of the ingredients which are very different in texture and pharmacological properties;and(3)boiling or hot water soaking,which is used to prepare decoctions for treating the syndrome of evil heat residing in the upper and evil cold residing in the lower.7 Special Procedures for Preparing DecoctionsThe special procedures for preparing decoctions include boiling beforehand,boiling afterwards,wrapping and boiling,melting in hot decoction liquid,boiling separately,mixing into hot decoction liquid,steeping in hot water or decoction liquid,boiling in decoction liquid,etc.The author of the master’s thesis analyzed the special procedures for preparing decoctions recorded in ancient recipes and modern literature,and made a chief summarization involving the practice of the procedures of boiling beforehand,boiling afterwards,and boiling in decoction liquid.The procedure of boiling beforehand is adopted to 3 types of decoction ingredients.Firstly,it is for boiling the ingredients originated from minerals and animals with shells,horns and carapace.These ingredients are of hard texture and their effective components are difficult to be extracted.In preparing a decoction these ingredients need to be broken to pieces and boiled beforehand for over 30 min.Secondly,it is for boiling the ingredients with known toxic effects.Because these ingredients contain toxicity,they need to be boiled beforehand for 60 min at first,or even for a longer time.Thirdly,in order to remove bias and make the efficacy of drug into middle and lower jiao.Besides,some ingredients originated from plants.such as Herba Ephedrae,Radix Puerariae Lobatae,Concretio Silicea Bambusae,Fructus Terminaliae Tomentellae Immaturus,Fructus Cannabis,Poria,Fructus et Semen Trichosanthis,and Herba Dendrobii Nobilis.Only if these ingredients are boiled beforehand for a certain time,can they exert their efficacy better.The procedure of boiling afterwards is adopted to boil the decoction ingredients which are rich in volatile components or contain the effective components liable to be devastated by a longer time of boiling or making efficacy of drug into upper jiao.In preparing a decoction these ingredients need to be added into the other ingredients for boiling together 5-15 min before the entire boiling are finished.Before being added into the other ingredients,these ingredients should be steeped in cold water for a certain time.And when it is the time for adding them,they are added into the other ingredients together with the steeping water.Being emphasized by the pharmacological predecessors in TCM,the procedure of boiling in decoction liquid is still worth attaching importance to at present.In the practice of this procedure,some ingredient is boiled at first and the decoction liquid this ingredient is then used as the water for boiling the rest of the ingredients in a decoction.There are 4 types of decoction ingredients which can be used for preparing the decoction liquid which is used later as the water for boiling the other ingredients in a decoction;(1)those which are mild and harmonious in nature and can be used as both herbs and food materials,such as sugarcane,Semen Benincasae,glutinous rice,abalone,and Semen Coicis,(2)those which can dominate the curative effect of a whole decoction,such as sugarcane,which can exert a dominating effect of clearing away heat and dryness in a decoction,and Flos Hemerocallis,which can dominate the effect of relieving depression of a decoction;(3)those which can lead the curative effect of a decoction into a focus of infection or an infected meridian,such as Semen Benincasae,which can lead the curative effect of a decoction into an edematous focus,and Ramulus Mori,which can lead the curative effect of a decoction into the liver meridian;and(4)those which are used in particularly large doses,such as Rhizoma Nelumbinis,which can be used in a dose as large as 3 liang,and Ramulus Mori,which can be used in a dose as large as 2 liang.In summary of the above discussion,6 key points are worthy of pointing out:(1)attention must be paid to the fact that the pharmacological properties of decoction ingredients can be influenced by the vessels used for boiling them;(2)the amount of time for soaking decoction ingredients adopted today may be properly prolonged because it used to be much longer;(3)both the amount of water used for boiling the regular decoction ingredients recorded in the literature published before the Tang Dynasty and that used for boiling the roughly-powdered decoction ingredients recorded in the literature published in the Song Dynasty,are worthy of being used as reference today;(4)as far as the time for boiling decoction ingredients is concerned,the relative boiling time is considered to be more rational than the absolute boiling time when being used for controlling the process of decoction preparation;(5)The thesis summarize the method of using water consumption to determine the decocting time through Jinguiyaolue(金匮要略),and divide into short time,middle time and long time decoction;and(6)both the procedures of boiling beforehand,boiling afterwards,and boiling in decoction liquid for preparing decoctions,and the examples of the experience in the administration of decoctions recorded in the ancient literature,have reference value to the present clinical administration of decoctions.This master’s thesis is of certain importance in advocating rational administration of decoctions,encouraging the establishment of the standards for preparing decoctions,and promoting the development of clinical TCM pharmacology and TCM pharmacy.