Available online at www.sciencedirect.com Chinese Journal of Natural Medicines 2021, 19(7): 505-520 doi: 10.1016/S1875-5364(21)60050-X •Review• A systematic review of pharmacological activities, toxicological mechanisms and pharmacokinetic studies on Aconitum alkaloids MI LiΔ, LI Yu-ChenΔ, SUN Meng-Ru, ZHANG Pei-Lin, LI Yi*, YANG Hua* State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China Available online 20 Jul., 2021 [ABSTRACT] The tubers and roots of Aconitum (Ranunculaceae) are widely used as heart medicine or analgesic agents for the treat- ment of coronary heart disease, chronic heart failure, rheumatoid arthritis and neuropathic pain since ancient times. As a type of natur- al products mainly extracted from Aconitum plants, Aconitum alkaloids have complex chemical structures and exert remarkable biolo- gical activity, which are mainly responsible for significant effects of Aconitum plants. The present review is to summarize the progress of the pharmacological, toxicological, and pharmacokinetic studies of Aconitum alkaloids, so as to provide evidence for better clinical application. Research data concerning pharmacological, toxicological and pharmacokinetic studies of Aconitum alkaloids were collec- ted from different scientific databases (PubMed, CNKI, Google Scholar, Baidu Scholar, and Web of Science) using the phrase Acon- itum alkaloids, as well as generic synonyms. Aconitum alkaloids are both bioactive compounds and toxic ingredients in Aconitum plants. They produce a wide range of pharmacological activities, including protecting the cardiovascular system, nervous system, and immune system and anti-cancer effects. Notably, Aconitum alkaloids also exert strong cardiac toxicity, neurotoxicity and liver toxicity, which are supported by clinical studies. Finally, pharmacokinetic studies indicated that cytochrome P450 proteins (CYPs) and efflux transporters (ETs) are closely related to the low bioavailability of Aconitum alkaloids and play an important role in their metabolism and detoxification in vivo. [KEY WORDS] Aconitum alkaloids; Pharmacological activities; Toxicity; Pharmacokinetics [CLC Number] R284, R917 [Document code] A [Article ID] 2095-6975(2021)07-0505-16 sites in their structures, aconitines can be further classified in- Introduction to diester-diterpenoid alkaloids (DDAs), monoester-diterpen- Aconitum alkaloids are bioactive components with com- oid alkaloids (MDAs), and hydramine diterpenoid alkaloids [9-11] plex chemical structures that mostly exist in plants of the two (HDAs) . With the sequential hydrolysis of ester bonds at [12, 13] genera Aconitum and Delphinium [1, 2], including the charac- C8 and C14, their toxicity was substantially reduced . In contrast, C -diterpene alkaloids are the least distributed teristic active and toxic components of diterpene alkaloids. 18 Aconitum alkaloids, and classified into lappaconitines and According to their chemical skeletons, diterpene ranaconitines [14-16]. Compared with lappaconitines, the hydro- alkaloids can be divided into C -, C -, and C -diterpene al- 18 19 20 gen at C site of ranaconitines was substituted by oxygen- kaloids, and their chemical structures are presented in 7 containing groups. Furthermore, the chemical skeletons of Fig. 1. C19-Diterpene alkaloids, the main types of Aconitum C -type diterpene alkaloids are complex and diverse, with [3] [4] [5] 20 alkaloids, include aconitines , lycoctonines , pyro-types , the common structural types of hetisines [17, 18], hetidines [19], [6] [7] [8] rearranged-types , 7, 17-seco-types , and lactone types . atisines [20], denudatines [21], veatchines [22] and napellines [23]. Based on the esterification of hydroxyl groups at C8 and C14 For exmaple, songorine is a typical active napelline-type C20- diterpene alkaloid extracted from Aconitum carmichaeli [24]. [Received on] 23-Jan.-2021 A large number of studies have confirmed that Aconitum [Research funding] This work was supported by the National Natur- alkaloids are the characteristic bioactive components of al Science Foundation of China (No. 81673592). Aconitum species, which exhibit substantial analgesic, anti- * [ Corresponding author] E-mail: [email protected] (LI Yi); inflammatory, antioxidant and anti-tumor activities [25, 26]. Tel/Fax: 86-25-8327-1220, E-mail: [email protected] (YANG Hua) However, due to a narrow therapeutic window, they may ∆These authors contributed equally to this work. cause toxicity to the heart, liver, muscle tissues and nervous [27, 28] These authors have no conflict of interest to declare. system . Thus, the use of Aconitum in herbal prepara- – 505 – MI Li, et al. / Chin J Nat Med, 2021, 19(7): 505-520 13 12 13 16 12 16 12 14 11 13 17 17 20 16 14 10 17 1 10 1 1 9 14 2 9 8 2 9 11 2 15 R 11 15 R N 8 15 R N 10 N 8 3 3 4 4 3 4 7 5 5 7 5 6 7 6 6 19 18 19 18 R R 18 C18-diterpene alkaloids C19-diterpene alkaloids C20-diterpene alkaloids aconitine type napelline type OH H O O O O O O O OH R OH N 1 N OH OH R2 O O N O O O O H OH N O Lappaconitine Acotinine R1 = C2H5 R2 = OH Songorine Mesacotinine R1 = CH3 R2 = OH Hypacotinine R1 = CH3 R2 = H Fig. 1 Classification, general structures and numbering systems for C18-, C19- and C20-diterpenen alkaloids and chemical struc- tures of classical diterpene alkaloids tions is limited in Europe and the United States [29]. In recent kaloids, so as to provide evidence for further development years, to elucidate the absorption and metabolism character- and clinical application of Aconitum drugs. istics of active or toxic alkaloids in the body, pharmacokinet- Pharmacological Activities of Aconitum Alkaloids ic studies have been widely performed, which indicate that Aconitum alkaloids can be quickly absorbed and widely dis- Effects on the cardiovascular system tributed in the body [30]. But the bioavailability of Aconitum Aconitum plants have long been used for the treatment of [29, 34] alkaloids is extremely low, while highly toxic alkaloids can heart failure and poor circulation , and Aconitum alkal- be converted into less toxic metabolites and soluble derivat- oids are the main active ingredients for cardioprotective ef- ives [31, 32], playing an important role in their metabolism and fects (Table 1). For instance, Fuzi total alkaloid (FTA) signi- detoxification in vivo. ficantly decreased myocardial damage and infract size in rats Recently, many efforts have been devoted to reviewing with myocardial infraction, which stabilized the cardiomyo- the phytochemical characteristics of Aconitum and its active cyte membrane structure through improving myocardial en- ergy metabolic abnormalities, phospholipids levels and distri- components as well as related pharmacological activity and [35] [26] bution patterns . Moreover, fuziline and neoline showed analytical methods. For instance, Zhou et al. presented an pronounced activity against pentobarbital sodium induced investigation concerning the safety application of Aconitum damage in cardiomyocytes, which was characterized in re- by summarizing the phytochemical and pharmacological stored beating rhythm and improved cell vitality [36]. C - activity and toxicity of Aconitum. Furthermore, Elshazly M et 19 Diterpenoid alkaloids such as mesaconine, hypaconine and al. [33] focused on liquid chromatography/mass spectrometry beiwutinine showed remarkable cardiac effects on the isol- analysis of Aconitum and its Chinese herbal medicine. Wu et [32] ated bullfrog hearts. Notably, the protective effects of mesa- al. illuminated the application of Fuzi as personalized conine were achieved by improving the inotropic effect and medicine from the respect of pharmacokinetics. So far, there left ventricular diastolic function in rats with myocardial has been no comprehensive and systematic review of Acon- ischemia-reperfusion injury [37]. Higenamine, a benzyltetrahy- itum alkaloids. Therefore, in the current review, we summar- droisoquinoline alkaloid, showed inhibitory effects on both ize the up-dated, comprehensive, and systematic information human and rat platelet aggregation, which was achieved by about the pharmacological activity and toxicity of Aconitum increasing the recovery rate in a mouse model of acute throm- alkaloids in the cardiovascular system, nervous system, liver, bosis, and lowering the weight of thrombus in an arterio-ven- and other organs, as well as the absorption and metabolic ous shunt (AV-shunt) rat model[38]. Meanwhile, higenamine characteristics of Aconitum alkaloids, and discuss the toxicity- was proved to increase the fibrinogen level, decrease fibrino- efficacy relationship and pharmacokinetics of Aconitum al- gen/fibrin degradation product (FDP) level and prothrombin – 506 – MI Li, et al. / Chin J Nat Med, 2021, 19(7): 505-520 Table 1 Effects of Aconitum alkaloids on the cardiovascular system Component/Dose/Duration Cell type/Animal model Effects Mechanisms Ref. Improve myocardial energy metabolic Radix Aconiti Lateralis Preparata abnormalities, change phospholipids extract (RAE) and Fuzi total Rats with myocardial Anti-myocardial levels and distribution patterns, and [35] alkaloid (FTA) 1.6, 0.8, and 0.4 infarction infarction effect stabilize the structure of cardiomyocyte g·kg−1 for 14 d membrane Against pentobarbital Fuziline and neoline 10, 1, and Neonatal rat Recover beating rhythm and increase sodium induced damage [36] 0.1 μmol·L−1 for 24 h cardiomyocytes cell viability in cardiomyocytes Mesaconine and hypaconine 5 Optimal cardiac action