Review of Modern Research on Toxicity of Traditional Chinese Medicine Aconm Lateralis Radix Praeparaia

Lingyu DENG, Si LIN, Huizhen QIN, Hua ZHU

Guangxi University of Chinese Medicine, Nanning 530200, China

Abstract The traditional Chinese medicine Aconm Lateralis Radix Praeparaia (Fuzi) is pungent and sweet in taste, hot in nature, and has high toxicity. It governs the meridians of the heart, kidney and spleen. It has the functions of restoring yang to save from collapse, dispersing cold and removing dampness, and warming the middle to relieve pain. It is often used for the treatment of yang collapse, cold limbs, weak pulse, heart yang deficiency, heart pain due to chest impediment, abdominal cold-pain, kidney yang deficiency, impotence and cold in womb, and syndrome of exogenous disease due to yang deficiency, etc. Its great yang qi and strong medicinal properties often bring about toxic and adverse effects. However, after processing or combination with other medicinal materials, the effects of Aconm Lateralis Radix Praeparaia are quite different. Not only the toxicity is greatly reduced, but also the curative effects are strengthened. Through searching related literature, this paper reviewed the researches about the toxicity reduction and curative effect improvement of Aconm Lateralis Radix Praeparaia, in order to provide a certain theoretic reference for future further research of Aconm Lateralis Radix Praeparaia.

Key words Aconm Lateralis Radix Praeparaia, Toxicity reduction and curative effect improvement, Review

1 Introduction

Aconm Lateralis Radix Praeparaia (Fuzi) is processed roots ofAconitumcarmichaeliDebx, herbaceous plant in Ranunculaceae family. It is mainly produced in Sichuan, Hunan, and Hubei provinces, with Sichuan as the production area of Aconm Lateralis Radix Praeparaia authentic medicinal material. Aconm Lateralis Radix Praeparaia is pungent and sweet in taste, hot in nature, and has toxicity. It governs the meridians of the heart, kidney and spleen, and can move 12 meridians[1]. As initially recorded inShennong’sClassicofMateriaMedicacompiled in East Han Dynasty, Aconm Lateralis Radix Praeparaia is pungent in taste and warm in nature, mainly used for treating wind-cold, cough with dyspnea, pathogenic qi, can warm the middle, treat tetanus, blood conglomeration, paralysis due to cold dampness, muscular constriction, and inability to walk due to knee pain[2].

Zhang Jingyue, a well-known physician in the Ming Dynasty, included Aconm Lateralis Radix Praeparaia together with Ginseng Radix Et Rhizoma (Renshen), Rehmanniae Radix Praeparata (Shudihuang), and Rhei Radix Et Rhizoma (Dahuang) into the "four mostly essential traditional Chinese medicines", and Aconm Lateralis Radix Praeparaia is a toxic traditional Chinese medicines commonly used in clinical practice. Famous physician Lu Zhuzhi (1876-1963, well known as Jinshou the Elderly in his old age) once said that Aconm Lateralis Radix Praeparaia is highly pungent, warm, and toxic, strong but soft, could treat exterior and interior, upper and lower diseases, it is a hero of traditional Chinese medicines; using it to treat patients, patients would get recovered and healthy; using it to treat a country, the people in the country would be harmonious; using it to treat the world, the world would get peaceful and prosperous forever. Due to its functions of restoring yang to save from collapse, dispersing cold and removing dampness, and warming the middle to relieve pain, Aconm Lateralis Radix Praeparaia is often used for the treatment of yang collapse, cold limbs, weak pulse, heart yang deficiency, heart pain due to chest impediment, abdominal cold-pain, kidney yang deficiency, impotence and cold in womb, and syndrome of exogenous disease due to yang deficiency,etc.Aconm Lateralis Radix Praeparaia has advantages of many Chinese medicines and is reputed as the first drug for restoring yang to save from collapse and the essential medicine for many yang deficiency syndromes and cold congealing pain symptoms. Famous physician Zhang Zhongjing flexibly applied Aconm Lateralis Radix Praeparaia in the clinical practice, such as Ganjiang Fuzi Decoction, Shaoyao Gancao Fuzi Decoction, Fuzi Xiexin Decoction, Guizhi Fuzi Decoction, and Mahuang Xixin Fuzi Decoction in his workTreatiseonColdDamageDiseases. In later generations, many famous physicians developed a lot of excellent prescriptions of Aconm Lateralis Radix Praeparaia, such as Daxuming Decoction and Xiaoxuming Decoction inEssentialPrescriptionsWorthaThousandGoldforEmergenciesby Sun Simiao in the Tang Dynasty and Jijiu Huiyang Decoction inCorrectionofErrorsinMedicalClassicsby Wang Qingren in the Qing Dynasty.

2 Toxicity understanding in the research on materia medica

Shennong’sClassicofMateriaMedica[3]initially recorded Aconm Lateralis Radix Praeparaia and considered it as low grade drug. The toxicity of Aconm Lateralis Radix Praeparaia was recorded inWritingsofPrinceHuainan[4], Tianxiong (Chinese name of Aconm Lateralis Radix Praeparaia) was highly toxic. As for properties of Aconm Lateralis Radix Praeparaia,SupplementaryRecordsofFamousPhysiciansby Tao Hongjing stated that it is sweet in nature and has high heat and high toxicity[5].RevisedMateriaMedicaoftheKaibaoEraalso had similar descriptions[6].MateriaMedicaforDecoctions[7]stated that it is pungent in taste, has strong yang, big heat and high toxicity. It can be seen that the toxicity of Aconm Lateralis Radix Praeparaia has been recognized by most of physicians since ancient times.VariorumofShennongsClassicofMateriaMedica[8]pointed out the relationship between its properties and growth environment, and stated that its pungent flavor, sweet taste and high heat and toxicity are resulted from growth environment ofAconitumcarmichaelii. Regarding its clinical manifestations, Zhang Zhicong in the Qing Dynasty recorded inReverencefortheOriginoftheMateriaMedica, that "Taking Aconm Lateralis Radix Praeparaia will cause fever and carbuncle poisoning; taking it will rotten the five internal organs, taking it this year, it will get poisoned the next year"[9].

NewEditiononMateriaMedica[10]pointed out the relationship between the toxicity and efficacy of Aconm Lateralis Radix Praeparaia, "the key of Aconm Lateralis Radix Praeparaia is to take its toxicity..., and its yang toxicity is first rate. Using toxicity to combat poison, the toxicity will not remain. Thus, once the cold is dispelled, yang will be restored. The mechanism of Aconm Lateralis Radix Praeparaia is like this." However, the toxic reaction after taking Aconm Lateralis Radix Praeparaia varies with individual. As records inCompendiumofMateriaMedica[11], someone takes a little dosage of Aconm Lateralis Radix Praeparaia, the cold is removed and dryness occurs, while someone has taken it for a long time but the efficacy is not very satisfactory…, which are due to difference of endowments of internal organs and could not be generalized by common sense." "Aconm Lateralis Radix Praeparaia should not be used until the disease is critical." Therefore, materia medica in the past often warned clinical use with caution, improper use may lead to death. Some physicians clearly stated that the toxicity of Aconm Lateralis Radix Praeparaia is due to improper clinical application. For example,CompleteWorksofJingyue[12]stated that if using Aconm Lateralis Radix Praeparaia properly, it is not toxic." In history, many poisoning and even death incidents of Aconm Lateralis Radix Praeparaia were actually caused by the misuse. For example,FeaturesofMateriaMedicapointed out that if not the disease of cold dampness or yang deficiency and qi weakness, misuse of Aconm Lateralis Radix Praeparaia for yin deficiency and internal heat, the disaster will come soon." According to records ofMateriaMedicaofAppropriateCompatibility[13], patients with blood deficiency engendering heat and wind would die if taking Aconm Lateralis Radix Praeparaia.DosageofEssentialDrugs[14]stated that Aconm Lateralis Radix Praeparaia is prohibited for all yang syndromes, fire syndromes, heat syndromes, yin deficiency internal heat, and blood deficiency syndromes. These show that the special property of Aconm Lateralis Radix Praeparaia is its toxicity. The individual’s physical factors and the accuracy of syndrome differentiation are important conditions that lead to the transformation of the role of Aconm Lateralis Radix Praeparaia to "effective" or "toxic". According toYellowEmperor’sInnerCanon, when a person is sick, the disease bears the properties and toxicity of the drug and will not harm the human body. If you are sick, you will suffer. According to this guiding principle, it is required to set up the concept of syndrome and syndrome differentiation, strictly prohibitting to use Aconm Lateralis Radix Praeparaia for patients with yin deficiency and internal heat. In addition, according to records ofEnlighteningPrimerofMateriaMedica[15], pregnent women should not use decoction of Aconm Lateralis Radix Praeparaia, otherwise, it will lead to abortion.

3 Toxicity understanding in modern medicine

Modern medicine generally believes that Aconm Lateralis Radix Praeparaia is pungent and sweet in taste, hot in nature, and is toxic. Yang-support physicians who are good at using Aconm Lateralis Radix Praeparaia consider that its toxicity is related to growth environment ofA.carmichaelii, and Aconm Lateralis Radix Praeparaia produced from Jiangyou, Mianyang City of Sichuan Province has the strongest toxicity. According to clinical reports, the toxicity of Aconm Lateralis Radix Praeparaia poisoning is mainly manifested in the cardiovascular system, nervous system, and digestive system. Such as numbness of the lips, tongue and limbs, oppression in the chest, breathing difficulty, dizziness, palpitation, burning sensation in the throat, esophagus, stomach, nausea and vomiting, shock, arrhythmia, coma, and even death in severe cases[16]. These are similar to what was said in ancient times. Further, modern research has found that the toxic substance basis of Aconm Lateralis Radix Praeparaia is ester-soluble alkaloids, especially diester alkaloids, and water-soluble alkaloids are their poison control components[17].

3.1 Material basis of the efficacyXuetal.[18]summarized and analyzed relevant domestic and foreign literature about Aconm Lateralis Radix Praeparaia and found that the main components of aconite are alkaloids, of which the C-19 type diterpene alkaloids of the aconitine skeleton are the main ones, followed by C-20 type diterpene alkaloids with skeleton types such as haitigenine type, vertine type, nalpipeline type and delphinium type as the main parts; apart from alkaloids, it also contains flavonoids, saponins, and ceramides,etc.The biological activities of Aconm Lateralis Radix Praeparaia mainly include heart strengthening, anti-tumor, anti-inflammatory and analgesic, immune enhancement, and anti-aging effects. Using modern chromatographic techniques, modern scholars have separated and purified 26 compounds from Aconm Lateralis Radix Praeparaia. According to the physicochemical properties and spectral data of the compounds (1H. NMR, 13C-NMR, 1H-1HCOSY, HSQC, HMBC, MS, IR), the chemical structures of 21 compounds were identified, including 10 C-19 diterpene alkaloids and two C-20 type diterpene alkaloids, two ceramide compounds, one base compound, two steroid compounds, and four fatty acid compounds[19].

3.2 Pharmacological effects

3.2.1Cardiovascular system. Aconm Lateralis Radix Praeparaia has obvious toxicity and efficacy. Zhouetal.[20]found that its toxic component is diester-type diterpene alkaloid, C8 acetyl ester group and C14 aromatic ester group are toxic groups; the parts of Aconm Lateralis Radix Praeparaia with obvious physiological activity are water-soluble part, diterpene alkaloids and polysaccharides. In addition, diester type diterpene alkaloids have obvious effects of lowering blood pressure, inhibiting myocardial contractility and anti-arrhythmia. In contrast to its water-soluble components’ boosting and heart-toning effects and the arrhythmogenic effects of diester-type diterpene alkaloids, they form obvious two-way effects; both show obvious effects of dilating blood vessels and increasing blood flow.

3.2.2Anti-tumor effects. Through the predictive analysis tool BATMAN-TCM and a variety of biological databases, combined withinvivoandinvitroexperiments, Songetal.[21]predicted the possible mechanism of higenamine (norcoclaurine) in regulating the occurrence and development of tumors. They found that higenamine may directly regulate tumor cell proliferation and apoptosis, or indirectly affect tumor occurrence and development by affecting cardiac function; animal experiments have shown that higenamine can significantly reduce the volume of colon cancer subcutaneously transplanted tumors (P<0.05), promote tumor cell apoptosis in tumor tissues, and significantly increase the level of atrial natriuretic peptide (ANP) in nude mice of colon cancer model (P<0.01); however, cell experiments have shown that higenamine had no direct killing effect on tumor cells. Higenamine is a main active component of Aconiti Lateralis Radix Praeparaia, it can inhibit the growth of colon cancer subcutaneously transplanted tumors, induce their apoptosis, and thus play an anti-tumor effect. The mechanism may be related to the promotion of the release of the cardiac peptide hormone ANP.

3.2.3Anti-inflammatory and and analgesic effects. When observing the compatibility of different proportions of Aconiti Lateralis Radix Praeparaia and Glycyrrhizae Radix Et Rhizoma (Gancao) in combination with pharmacological experiments to explore the effects of the main active components on the dissolution rate, Lietal.[22]found that in the experiment of acetic acid writhing method for analgesia and xylene inflammation, the glycyrrhizae Radix Et Rhizoma compatibility group 1∶3 had the best effect. In the physical analgesic experiments with hot plate method, the Glycyrrhizae Radix Et Rhizoma and Aconiti Lateralis Radix Praeparaia compatibility group 3∶1 had the best effect. It has shown that with increase of liquiritin, the dissolution of aconitine tends to increase. Specifically, when the ratio of Glycyrrhizae Radix Et Rhizoma to Aconiti Lateralis Radix Praeparaia is 3∶1, the dissolution of aconitine in the decoction is the highest; when the ratio is 1∶3, the dissolution of liquiritin in the decoction is the highest. Besides, liquiritin may be the main component of antispasmodic, analgesic and anti-inflammatory; aconitine is the main component of inhibiting pain nerves and reducing pain.

3.2.4Immunomodulatory effect. In traditional Chinese medicines, Aconiti Lateralis Radix Praeparaia is widely used as an anti-tumor drug or an adjuvant drug for radiotherapy and chemotherapy. Some study explored the anti-tumor and immunomodulatory effects of Aconiti Lateralis Radix Praeparaia combined with radiotherapy on Lewis lung cancer (LLC) mice, and found that Aconiti Lateralis Radix Praeparaia combined with radiotherapy can significantly inhibit the growth of LLC, promote cancer cell apoptosis, and prolong the survival period of LLC mice. The mechanism is to reduce the proportion of Treg cells. After radiotherapy, the levels of serum interleukin (IL)-10 and transforming growth factor (TGF)-β in LLC mice are reduced, and the expression of programmed death ligand-1 is down-regulated. These indicate that Aconiti Lateralis Radix Praeparaia has an immunomodulatory effect and can be used as a radiosensitizer to improve the radiotherapy effect of lung cancer[23].

4 Research on toxicity reduction and efficacy improvement of Aconiti Lateralis Radix Praeparaia

4.1 Compatibility

4.1.1Compatibility of Aconiti Lateralis Radix Praeparaia with Glycyrrhizae Radix Et Rhizoma. Based on the previous research work, from the three levels, namely, ininvitroco-decoction process, the components of Glycyrrhizae Radix Et Rhizoma reducing the content of toxic components in Aconiti Lateralis Radix Praeparaia through hydrolysis, lipid exchange and formation of associations, active components of Glycyrrhizae Radix Et Rhizoma affecting the metabolism of toxic components in the body, as well as the direct biological antagonistic effect on the cardiotoxicity of Aconiti Lateralis Radix Praeparaia, Ma Linaetal.[24]found that Glycyrrhizae Radix Et Rhizoma exerts its unique antagonistic effect on the toxicity of Aconiti Lateralis Radix Praeparaia mainly through the following three ways: directly reducing the content of toxic components in their co-decoction; changing the metabolism process of the toxic components in the body; direct biological antagonistic effect. After Glycyrrhizae Radix Et Rhizoma is compatible with Aconiti Lateralis Radix Praeparaia, with the addition of acidic components in Glycyrrhizae Radix Et Rhizoma, it not only further promotes the hydrolysis and lipid exchange of the more toxic diester alkaloids, but it can also form associations with acidic components in Glycyrrhizae Radix Et Rhizoma to slowly release to achieve a slow and controlled release effect. In addition, Glycyrrhizae Radix Et Rhizoma also changes the metabolic parameters of the main components of Aconiti Lateralis Radix Praeparaia through its influence on liver drug enzymes, especially reducing the peak concentration and the area under the curve of plasma drug concentration.

4.1.2Compatibility of Aconiti Lateralis Radix Praeparaia with Rehmanniae Radix (Dihuang). Through measuring the enzyme activities of CYP1A2 and CYP3A4 in rat liver microsomes, Li Qiuhongetal.[25]clarified the effects of Aconiti Lateralis Radix Praeparaia and dried Rehmanniae Radix on CYP450 enzyme protein and gene expression from the protein and transcription level, and accordingly explored the molecular mechanism of Aconiti Lateralis Radix Praeparaia and dried Rehmanniae Radix reducing the toxicity of Aconiti Lateralis Radix Praeparaia. They found that, compared with the blank group, the CYP1A2 and CYP3A4 enzyme activities and mRNA expression in Aconiti Lateralis Radix Praeparaia and dried Rehmanniae Radix group were significantly increased (P<0.05); the CYP450 content of Aconiti Lateralis Radix Praeparaia group was significantly reduced (P<0.01); the CYP450 content of both the dried Rehmanniae Radix group and Aconiti Lateralis Radix Praeparaia and dried Rehmanniae Radix group were significantly increased (P<0.05). Therefore, the compatibility of Aconiti Lateralis Radix Praeparaia with Rehmanniae Radix can induce CYP1A2 and CYP3A4 enzyme activities, increase the CYP450 enzyme content, accelerate the metabolism of the toxic components of Aconiti Lateralis Radix Praeparaia, and achieve the toxicity reduction effect.

4.1.3Compatibility of Aconiti Lateralis Radix Praeparaia with Paeoniae Radix Alba (Shaoyao). Through establishing a Cocktail probe drug method and aninvitroliver microsome incubation system, Guo Yanlietal.[26]measured the activities of CYP1A2 and CYP3A4 enzymes in rat liver microsomes, and explained the effects of the compatibility of Aconiti Lateralis Radix Praeparaia and Paeoniae Radix Alba on the expression of CYP450 enzyme genes from the level of protein and transcription, so as to explain the toxicity reduction mechanism of the compatibility of Aconiti Lateralis Radix Praeparaia with Paeoniae Radix Alba. The results showed that compared with the blank group, the CYP1A2 enzyme activity of the Paeoniae Radix Alba group was significantly different (P<0.05), and the expression of CYP1A2 enzyme mRNA in the Paeoniae Radix Alba group was increased, and the difference was extremely significant (P<0.01); the Aconiti Lateralis Radix Praeparaia and Paeoniae Radix Alba group had an inducing effect on CYP1A2 enzyme, and the difference was extremely significant (P<0.01); the CYP1A2 enzyme mRNA expression in the Aconiti Lateralis Radix Praeparaia and Paeoniae Radix Alba group was increased, and the difference was significant (P<0.05). The compatibility of Aconiti Lateralis Radix Praeparaia with Paeoniae Radix Alba can induce CYP1A2 enzyme activity, increase the mRNA expression of CYP1A2 enzyme gene, accelerate the metabolic process of the toxic components of Aconiti Lateralis Radix Praeparaia, and then achieve the toxicity reduction effect.

4.1.4Compatibility of Aconiti Lateralis Radix Praeparaia with Pinelliae Rhizoma (Banxia). Some scholars introduced the discussion of Aconiti Lateralis Radix Praeparaia and Pinelliae Rhizoma by the master of traditional Chinese medicine, Professor Jin Shiyuan, summarized the relevant discourses and modern applications of the physicians in the past and combined Mr. Jin’s discussion on the preparation methods of Aconiti Lateralis Radix Praeparaia and Pinelliae Rhizoma. It was found that, clinically, appropriate processing methods could reduce the toxicity and improve the efficacy, syndrome differentiation of Aconiti Lateralis Radix Praeparaia and Pinelliae Rhizoma has excellent curative effect[27].

4.2 ProcessingAconiti Lateralis Radix Praeparaia is a medicine of strengthening the body resistance to eliminate pathogenic factors, and also a well-known toxic drug. In order to ensure the efficacy and safe use of medicines, it is mostly used after processing. Physicians in the past have recorded different methods of processing Aconiti Lateralis Radix Praeparaia. There are differences in the processing methods of Aconiti Lateralis Radix Praeparaia recorded in modern pharmacopoeia and ancient medical books. Studies have shown that with the evolution of dynasties, the processing and use methods of Aconiti Lateralis Radix Praeparaia have changed, and the ancient and modern processing methods are also different. Before the Tang Dynasty, Aconiti Lateralis Radix Praeparaia was mainly processed and soaked. During the Tang Dynasty and Ming Dynasty, it was mainly processed, soaked, or stir-heated. In the Qing Dynasty, it was mainly soaked and boiled. In modern days, it is mainly processed by water boiling and soaking[28].

4.2.1Process of using both water and fire. Some scholars have conducted acute toxicity testsinvivoby using rodent models and zebrafish models, and analyzed chemical components by high performance liquid chromatography (HPLC) and UPLC-MS. The results show that with the extension of the decoction time, the toxic aconitine component was hydrolyzed into benzoyl derivatives. But the aconitine component was not detected at 2 h after decoction of Aconiti Lateralis Radix Praeparaia, indicating that FZ-120 seems to be non-toxic. Different from non-decocted Aconiti Lateralis Radix Praeparaia (FZ-0) and 60 min decoction of Aconiti Lateralis Radix Praeparaia (FZ-60) which have lethal toxicity, FZ-120 did not cause any death or side effects on the body weight and biochemical indicators of mice at a dose of 130 g/kg[29]. This also proved that long-term decoction of Aconiti Lateralis Radix Praeparaia has the effect of reducing the toxicity.

Liuetal.[30]analyzed the alkaloid components of 5 kinds of Aconiti Lateralis Radix Praeparaia processed products by using acid dye colorimetry and high performance liquid chromatography and found that the quality of Aconiti Lateralis Radix Praeparaia produced in Jiangyou of Sichuan is the best, peeling can increase the relative content of its effective components; Heishunpian and Shufupian made with Danba can significantly reduce the content of diester alkaloids, which are toxic components, but at the same time, the active component monoester alkaloids and total alkaloids are lost seriously; cooking or frying without Danba can effectively remove the toxic components and retain the effective components, and the "detoxification and property retention" ability is better. Therefore, different processing methods can reduce the content of diester-type alkaloids, the toxic component of Aconiti Lateralis Radix Praeparaia, and increase the content of monoester-type alkaloids, the active components, to achieve the purpose of increasing the efficacy and reducing toxicity.

4.2.2Microwave processing. Through studying the influencing factors of microwave processing of Aconiti Lateralis Radix Praeparaia, Heetal.[31]found that at the same processing time, under microwave power of 550 W, the drying time and speed of microwave processing was the shortest and fastest, diester-type aconitine content was low, and total alkaloid content was high, but with the increase of the processing time, under the higher microwave power, Aconiti Lateralis Radix Praeparaia was easier to be processed brown. Therefore, suitable thickness, reconstitution rate, microwave power, and processing time are helpful for sufficiently reducing the toxicity and improving the processed quality of Aconiti Lateralis Radix Praeparaia.

4.2.3Processing with salt. Using Danba, magnesium chloride, sodium chloride, calcium chloride, potassium chloride as auxiliary materials to prepare raw Aconiti Lateralis Radix Praeparaia, combined with high performance liquid chromatography, Zhangetal.[32]determined the content of 6 kinds of ester alkaloids in the raw Aconiti Lateralis Radix Praeparaia and the above 5 kinds of salt processed products, compared the content of 6 kinds of ester alkaloids in the raw Aconiti Lateralis Radix Praeparaia and its 5 kinds of salt processed products. The results show that the processing method with the above 5 salt as auxiliary materials had different degrees of effects of "efficacy improvement and toxicity reduction". Specifically, magnesium chloride, potassium chloride, and calcium chloride had the best processing effect and can be used for the processing of Aconiti Lateralis Radix Praeparaia.

5 Conclusions

Materia Medica in the past believed that Aconiti Lateralis Radix Praeparaia is toxic, and the toxicity is closely related to its efficacy. The toxicity is related to the pathological state, and it can be detoxified by processing and compatibility. The modern understanding of toxicity of Aconiti Lateralis Radix Praeparaia not only inherits ancient theories, but also integrates with modern science on this basis, and develops it. However, there are certain different opinions in terms of dosage and processing methods. Therefore, it is necessary to study the relationship actively and deeply among diseases, syndromes, dosages, processed products, material basis, efficacy, safety,etc., and establish a more comprehensive, objective, efficient and practical toxicity control system, make Aconiti Lateralis Radix Praeparaia better serve the clinic.