Study of Aconitine toxicity in rat embryos in vitro

An insight into current advances on pharmacology, pharmacokinetics, toxicity and detoxification of aconitine

Aconitine is a diterpenoid alkaloid, which mainly exists in the plants of Aconitum. In the last decade, a plethora of studies on the pharmacological activities of aconitine has been conducted and demonstrated that aconitine possessed an extensive range of pharmacological activities such as anti-tumor, anti-inflammatory, analgesic, local anesthesia, and immunomodulatory effects. Pharmacokinetic studies indicated that aconitine may have the characteristics of poor bioavailability, wide distribution, and slow elimination. However, studies have also found that aconitine has toxic effects on the heart, nerves, embryos, etc. Therefore, we believe that aconitine may not be suitable for heart patients and pregnant women to treat related diseases. It is important to note that all of these pharmacological effects require further high-quality studies to determine the clinical efficacy of aconitine. This review aims to summarize the advances in pharmacological, pharmacokinetics, toxicity, and detoxification of aconitine in the last decade with an emphasis on its anti-tumor and anti-inflammatory activities, to provide researchers with the latest information and point out the limitations of relevant research at the current stage and the aspects that should be strengthened in future research.

Validation, Optimization, and Application of the Zebrafish Developmental Toxicity Assay for Pharmaceuticals Under the ICH S5(R3) Guideline

The zebrafish as an alternative animal model for developmental toxicity testing has been extensively investigated, but its assay protocol was not harmonized yet. This study has validated and optimized the zebrafish developmental toxicity assay previously reported by multiple inter-laboratory studies in the United States and Europe. In this study, using this classical protocol, of 31 ICH-positive compounds, 23 compounds (74.2%) were teratogenic in zebrafish, five had false-negative results, and three were neither teratogenic nor non-teratogenic according to the protocol standard; of 14 ICH-negative compounds, 12 compounds (85.7%) were non-teratogenic in zebrafish and two had false-positive results. After we added an additional TI value in the zebrafish treated with testing compounds at 2 dpf along with the original 5 dpf, proposed a new category as the uncategorized compounds for those TI values smaller than the cutoff both at 2 dpf and 5 dpf but inducing toxic phenotypes, refined the testing concentration ranges, and optimized the TI cut-off value from ≥ 10 to ≥ 3 for compounds with refined testing concentrations, this optimized zebrafish developmental assay reached 90.3% sensitivity (28/31 positive compounds were teratogenic in zebrafish) and 88.9% (40/45) overall predictability. Our results from this study strongly support the use of zebrafish as an alternative in vivo method for screening and assessing the teratogenicity of candidate drugs for regulatory acceptance.

The toxicology and detoxification of Aconitum: traditional and modern views

Aconitum carmichaeli Debx.-derived herbal medicine has been used for anti-inflammation and anti-arrhythmia purpose for more than two thousand years. It is processed into Chuanwu (Radix Aconiti praeparata) and Fuzi (Radix Aconiti lateralis praeparata) in Traditional Chinese Medicine, which are two useful drugs but with toxic properties. There have been patients poisoned by accidental ingestion of Aconitum plants or misuse of the herbal drug, and this is of great concern to study in-depth. In this review, we provided the traditional and contemporary practice of using Aconitum herbs as medicine, from functions, processing methods to toxicity in ethnomedicine aspects to discuss the underlying connections of traditional and modern understanding on the toxicity of Aconitum plants. We summarized the functions and toxicology of the herbal drugs are analyzed from chemical and clinical aspects, with the help of traditional and modern knowledge of medicine. The medicinal doses and lethal doses determined by researches are summarized, and the usage and processing methods are updated and reviewed in the modern view. In addition, clinical management of poisoned cases using western medicine is discussed. This review provides insights and awareness of safety when using Aconitum-derived herbal medicine, and the application of modern scientific knowledge to optimize the detoxification processes. We suggest the possibility to renew the current standard processing method from the official Pharmacopoeia all over the world.

Assessment of reproductive toxicity and genotoxicity of Aconiti Lateralis Radix Praeparata and its processed products in male mice

ETHNOPHARMACOLOGICAL RELEVANCE

Aconiti Lateralis Radix Praeparata (Chinese name: Fuzi), the root of Aconitum carmichaelii Debx., is a representative medicine for restoring yang and rescuing patient from collapse. However, less studies had been reported on the reproductive toxicity and genotoxicity of Fuzi. According to the principle of reducing toxicity and preserving efficiency, only processed products of Fuzi are commonly applied in clinic, including Baifupian, Heishunpian and Danfupian. However, whether processing could alleviate the reproductive toxicity and genotoxicity of Fuzi had not been revealed.

AIM OF THE STUDY

To assess the effect and possible mechanism of Fuzi and its processed products on reproductive toxicity and genotoxicity in male mice.

MATERIALS AND METHODS

Aqueous extracts of Fuzi and its processed products (Baifupian, Heishunpian and Danfupian, 5.85 g/kg) were administrated by gavage once daily for fourteen consecutive days. The reproductive toxicity was evaluated by testis weight, testis ratio, testis histopathology, sperm count, sperm viability rate and sperm deformity rate. The genotoxicity was evaluated by comet assay and micronucleus test in sperm, peripheral blood cell and bone marrow cell. Possible mechanisms of attenuating toxicity by processing were analyzed by detecting the level of testosterone, superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA) and catalase (CAT).

RESULTS

Fuzi significantly caused different degrees of reproductive toxicity and genotoxicity, specifically reducing the weight and testicular coefficient of testis, causing obvious pathological changes in testicular tissue, reducing sperm count and sperm viability rate, increasing sperm deformity rate and DNA damage in sperm/peripheral blood cells/bone marrow cells. Moreover, Fuzi decreased the level of testosterone, SOD, GSH and CAT, while increased the level of MDA in serum. Notably, the reproductive toxicity and genotoxicity induced by the processed products, especially Heishunpian and Danfupian, were significantly lowered compared to Fuzi. Processing could increase the level of testosterone, SOD, GSH, CAT and decrease the level of MDA compared to Fuzi.

CONCLUSION

Fuzi and its processed products had reproductive toxicity and genotoxicity, but the toxicity of processed products was significantly weakened compared to Fuzi. The protective mechanism of processing to reduce the toxicity of Fuzi might be related to increasing the level of testosterone and decreasing oxidative stress.

Aconitine induces mitochondrial energy metabolism dysfunction through inhibition of AMPK signaling and interference with mitochondrial dynamics in SH-SY5Y cells

Aconitine, a highly toxic alkaloid derived from Aconitum L., affects the central nervous system and peripheral nervous system. However, the underlying mechanism of aconitine-induced neurotoxicity remains unclear. This study investigates the effects and mechanism of aconitine on mitochondrial energy metabolism in SH-SY5Y cells. Results demonstrated that aconitine exposure suppressed cell proliferation and led to an increase in reactive oxygen species (ROS) and excessive lactate dehydrogenase (LDH) release. Aconitine (400 μmol/L) induced abnormal mitochondrial energy metabolism that quantified by the significant decrease in ATP production, basal respiration, proton leak, maximal respiration, and succinate dehydrogenase (SDH) activity. Phosphorylation of AMPK was significantly reduced in aconitine-treated SH-SY5Y cells. The AMPK activator AIACR pretreatment effectively promoted ATP production to ameliorate mitochondrial energy metabolism disorder caused by aconitine. Mitochondrial biosynthesis was inhibited after treatment with 400 μmol/L aconitine, which was characterized by mitochondria number, TFAM expression, and mtDNA copy number. Moreover, aconitine prompted the down-regulation of mitochondrial fusion proteins OPA1, Mfn1 and Mfn2, and the up-regulation of mitochondrial fission proteins p-Drp1 and p-Mff. These results suggest that aconitine induces mitochondrial energy metabolism dysfunction in SH-SY5Y cells, which may involve the inhibition of AMPK signaling and abnormal mitochondrial dynamics.

Involvement of Nrf2-HO-1/JNK-Erk Signaling Pathways in Aconitine-Induced Developmental Toxicity, Oxidative Stress, and ROS-Mitochondrial Apoptosis in Zebrafish Embryos

Aconitine (AC), one of the bioactive diterpenoid alkaloids extracted from Aconitum plants, is widely used in traditional herbal medicine to treat various diseases. Emerging evidence indicates that AC has attracted great interest for its wide cardiotoxicity and neurotoxicity. However, the toxic effects of AC on embryonic development and its underlying mechanisms remain unclear. Here, a developmental toxicity assay of AC was performed on zebrafish embryos from 4 to 96 h post fertilization (hpf), and its underlying mechanisms were discussed. AC exposure impaired the cardiac, liver, and neurodevelopment. Especially, a high dose of AC (7.27 and 8.23 μM) exposure resulted in malformations at 72 and 96 hpf, including reduced body length, curved body shape, pericardial edema, yolk retention, swim bladder and brain developmental deficiency, and degeneration of dopaminergic neurons. High-concentration AC exposure caused a deficient cardiovascular system with cardiac dysfunctions, increased heart rates at 72 and 96 hpf, and reduced locomotor behavior at 120 hpf. AC treatment significantly increased the ROS level and triggered cell apoptosis in the heart and brain regions of embryos at 96 hpf in 7.27 and 8.23 μM AC treatment zebrafish. Oxidative stress was confirmed by reduced levels of T-SOD activity associated with accumulation of lipid peroxidation in larvae. The expression levels of oxidative stress-related genes (Nrf2, HO-1, Cat, and Sod-1) Erk1/2 and Bcl-2 were significantly downregulated at 96 hpf. The expression pattern of JNK and mitochondrial apoptosis-related genes (Bad, Bax, Cyto C, Casp-9, and Casp-3) was significantly upregulated. Taken together, all these parameters collectively provide the first evidence of AC-induced developmental toxicity in zebrafish embryo/larvae through ROS-medicated mitochondrial apoptosis involving Nrf2/HO-1 and JNK/Erk pathways.

Identification of key transporters mediating uptake of aconitum alkaloids into the liver and kidneys and the potential mechanism of detoxification by active ingredients of liquorice

Aconite as a commonly used herb has been extensively applied in the treatment of rheumatoid arthritis, as pain relief, as well as for its cardiotonic actions. Aconitum alkaloids have been shown to be the most potent ingredients in aconite, in terms of efficacy against disease, but they are also highly toxic. Apart from neurological and cardiovascular toxicity exposed, the damage to hepatocytes and nephrocytes with long-term use of aconitum alkaloids should also be carefully considered. This study attempted to investigate the critical role of uptake transporters mediating the transport of aconitum alkaloids into the liver and the kidneys. The resulting data revealed that hOATP1B1, 1B3, hOCT1 and hOAT3 were mainly involved in the uptake of aconitum alkaloids. Additionally, the inhibitory effects of bioactive ingredients of liquorice on uptake transporters were screened and further confirmed by determining the IC₅₀ values. The in vitro study suggested that liquorice might lower the toxicity of aconite by reducing its exposure in the liver and/or kidneys through inhibition of uptake transporters. Eventually, the in vivo study was indicative of detoxification of liquorice by decreasing the exposure of aconitine as representative compound in liver after co-administration, even though the exposure in kidney altered was less significant. In summary, hOATP1B1, 1B3, hOCT1 and hOCT3 were determined as the key uptake transporters mediating the transport process of aconitum alkaloids into the liver and/or kidneys, and liquorice may alleviate the toxicity caused by reduction of exposure through inhibition of those key uptake transporters.

Liquorice may alleviate the toxicity of bioactive ingredients of aconite by inhibiting transporters mediating uptake in the liver/kidneys.

Research progress of aconitine toxicity and forensic analysis of aconitine poisoning

Chinese herbal medicines have been extensively used in China and other countries for centuries. Aconitine, a diterpenoid alkaloid extracted from Aconitum plants, has anti-inflammatory and analgesic activities, but can also induce severe arrhythmia and neurotoxicity. Aconitine poisoning accidents caused by misuse, suicide, or homicide have been reported in recent years. In China, fatal aconitine poisoning can occasionally happen on account of accidental ingestion of some wild plants or consumption of herbal decoction made from the roots of Aconitum plants. However, it is rather difficult for forensic experts to find the specific results in present forensic autopsy of aconitine-induced death. To further clarify its potential risk following the widespread application of aconitine, toxicological characteristics and pharmacokinetics of aconitine are reviewed. Moreover, gastrointestinal, neurological, and cardiovascular symptoms were observed frequently in aconitine poisoning cases. In addition, the review also aims at providing some convincing evidences for forensic experts to identify unexplained death with postmortem examination.

NMR-based metabonomics study on the effect of Gancao in the attenuation of toxicity in rats induced by Fuzi

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzi, the processed lateral root of Aconitum carmichaelii Debeaux, is a traditional Chinese medicine used for its analgesic, antipyretic, anti-rheumatoid arthritis and anti-inflammation effects; however, it is also well known for its toxicity. Gancao, the root of Glycyrrhiza uralensis Fisch., is often used concurrently with Fuzi to alleviate its toxicity. However, the mechanism of detoxication is still not well clear.

AIM OF THE STUDY

In this study, the effect of Gancao on the metabolic changes induced by Fuzi was investigated by NMR-based metabonomic approaches.

MATERIALS AND METHODS

Fifty male Wistar rats were randomly divided into five groups (group A: control, group B: Fuzi decoction alone, group C: Gancao decoction alone, group D: Fuzi decoction and Gancao decoction simultaneously, group E: Fuzi decoction 5h after Gancao decoction) and urine samples were collected for NMR-based metabolic profiling analysis. Statistical analyses such as unsupervised PCA, t-test, hierarchical cluster, and pathway analysis were used to detect the effects of Gancao on the metabolic changes induced by Fuzi.

RESULTS

The behavioral and biochemical characteristics showed that Fuzi exhibited toxic effects on treated rats (group B) and statistical analyses showed that their metabolic profiles were in contrast to those in groups A and C. However, when Fuzi was administered with Gancao, the metabolic profiles became similar to controls, whereby Gancao reduced the levels of trimethylamine N-oxide, betaine, dimethylglycine, valine, acetoacetate, citrate, fumarate, 2-ketoglutarate and hippurate, and regulated the concentrations of taurine and 3-hydroxybutyrate, resulting in a decrease in toxicity. Furthermore, important pathways that are known to be involved in the effect of Gancao on Fuzi, including phenylalanine, tyrosine and tryptophan biosynthesis, the synthesis and degradation of ketone bodies, and the TCA cycle, were altered in co-treated rats.

CONCLUSIONS

Gancao treatment mitigated the metabolic changes altered by Fuzi administration in rats, demonstrating that dosing with Gancao could reduce the toxicity of Fuzi at the metabolic level. Fuzi and Gancao administered simultaneously resulted in improved toxicity reduction than when Gancao was administrated 5h prior to Fuzi. In summary, co-administration of Gancao with Fuzi reduces toxicity at the metabolic level.

Screening and verification of linearly dependent biomarkers with acute toxicity induced by Aconiti Radix based on liquid chromatography-mass spectrometry-based metabolite profiling

We built a method that has three parts: first is to screen the biomarkers with metabolic profiling analysis; second is to determine the linear dependence with acute toxicity biomarkers; third is to validate the biomarkers with different Aconiti Radix involved medicine.

Metabonomics study of the effects of pretreatment with glycyrrhetinic acid on mesaconitine-induced toxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aconitum carmichaelii Debx. (Fuzi), a commonly use traditional Chinese medicine (TCM), has often been used in combination with Rhizoma Glycyrrhizae (Gancao) to reduce its toxicity due to diester diterpenoid alkaloids aconitine, mesaconitine, and hypaconitine. However, the mechanism of detoxication is still unclear. Glycyrrhetinic acid (GA) is the metabolite of glycyrrhizinic acid (GL), the major component of Gancao. In present study, the effect of GA on the changes of metabolic profiles induced by mesaconitine was investigated using NMR-based metabolomic approaches.

MATERIALS AND METHODS

Fifteen male Wistar rats were divided into a control group, a group administered mesaconitine alone, and a group administered mesaconitine with one pretreatment with GA. Their urine samples were used for NMR spectroscopic metabolic profiling. Statistical analyses such as orthogonal projections to latent structures-discriminant analysis (OPLS-DA), t-test, hierarchical cluster, and pathway analysis were used to detect the effects of pretreatment with GA on mesaconitine-induced toxicity.

RESULTS

The OPLS-DA score plots showed the metabolic profiles of GA-pretreated rats apparently approach to those of normal rats compared to mesaconitine-induced rats. From the t-test and boxplot results, the concentrations of leucine/isoleucine, lactate, acetate, succinate, trimethylamine (TMA), dimethylglycine (DMG), 2-oxo-glutarate, creatinine/creatine, glycine, hippurate, tyrosine and benzoate were significantly changed in metabolic profiles of mesaconitine-induced rats. The disturbed metabolic pathways include amino acid biosynthesis and metabolism.

CONCLUSIONS

GA-pretreatment can mitigate the metabolic changes caused by mesaconitine-treatment on rats, indicating that prophylaxis with GA could reduce the toxicity of mesaconitine at the metabolic level.

In vitro and in vivo anticancer activity of aconitine on melanoma cell line B16

The anti-tumor effect of aconitine in melanoma cell line B16 has been studied in this paper. We found that B16 cells showed significantly reduced growth rates and increased apoptotic effects in the presence of aconitine. Furthermore, aconitine inhibited the PI3K/AKT and MAPK/ERK1/2 signaling pathways, thus regulating the levels of protein and mRNA of PCNA and apoptotic related signaling molecules. Above all, we found that aconitine showed an anti-melanoma effect in suppressing tumor growth in vivo. In conclusion, we show that aconitine may be a useful anticancer drug in the future.

Overview of developmental and reproductive toxicity research in China: history, funding mechanisms, and frontiers of the research

Reproductive and developmental toxicology (DART) is the discipline that deals with adverse effects on male and female resulting from exposures to harmful chemical and physical agents. DART research in China boasted a long history, but presently has fallen behind the western world in education and research. The funding mechanisms for DART research in China were similar to that for other toxicological disciplines, and the funding has come from research grants and fellowships provided by national, ministerial, and provincial institutions. Finally, the frontiers of DART research in China could be summarized as follows: (1) use of model animals such as the zebrafish and roundworm, and use of cutting-edge techniques such as stem cell culture, as well as transgenic, metabonomic, and virtual screening to study the mechanisms of developmental toxicity for some important toxicants in China; (2) use of model animals and other lower-level sentinel organisms to evaluate and monitor the developmental toxicogical risk of environmental chemicals or pollutants; (3) epidemiological studies of some important reproductive hazards; (4) in-depth studying of the reproductive and developmental toxicity of some important environmental chemicals; and (5) evaluation and study of the reproductive and developmental toxicity of traditional Chinese medicines.

Aconitum in traditional Chinese medicine: a valuable drug or an unpredictable risk?

Aconitum species have been used in China as an essential drug in Traditional Chinese Medicine (TCM) for 2000 years. Reviewing the clinical application of Aconitum, their pharmacological effects, toxicity and detoxifying measures, herb-herb interactions, clinical taboos, famous herbal formulas, traditional and current herbal processing methods based upon a wide range of literature investigations serve as a case study to explore the multidisciplinary implications of botanicals used in TCM. The toxicological risk of improper usage of Aconitum remains very high, especially in countries like China, India and Japan. The toxicity of Aconitum mainly derives from the diester diterpene alkaloids (DDAs) including aconitine (AC), mesaconitine (MA) and hypaconitine (HA). They can be decomposed into less or non-toxic derivatives through Chinese traditional processing methods (Paozhi), which play an essential role in detoxification. Using Paozhi, the three main forms of processed aconite -- yanfuzi, heishunpian and baifupian -- can be obtained (CPCommission, 2005). Moreover, some new processing techniques have been developed in China such as pressure-steaming. The current development of fingerprint assays, in particular HPLC, has set a good basis to conduct an appropriate quality control for TCM crude herbs and their ready-made products. Therefore, a stipulation for a maximum level of DDA content of Aconitum is highly desirable in order to guarantee the clinical safety and its low toxicity in decoctions. Newly developed HPLC methods have made the accurate and simultaneous determination and quantification of DDA content interesting.