Study on the potential nephrotoxicity and mutagenicity of aristolochic acid IVa and its mechanism

Discrimination of poisonous and medicinal plants with similar appearance (Asarum heterotropoides vs. Cynanchum paniculatum) via a fusion method of E-nose, E-tongue, LC-HR-Q-TOF-MS/MS, and electrochemical fingerprint spectra

Introduction

The similarity in appearance of poisonous and medicinal plants, such as Asarum heterotropoides (AH) and Cynanchum paniculatum (CP), poses safety risks due to frequent confusion. Since AH contains toxic ingredients, the traditional methods of olfactory and gustatory identification cannot be used to distinguish AH from CP.

Methods

To differentiate them systematically, we proposed a novel strategy based on dual electronic sensors (DES) and dual fingerprint spectra (DFS). The DES included two intelligent sensors, namely the E-nose and E-tongue, which differentiated AH and CP based on odor and taste, respectively. DFS comprised chemical fingerprint spectra obtained through LC-HR-Q-TOF-MS/MS and electrochemical fingerprint spectra derived from the Belousov-Zhabotinsky reaction, differentiating AH and CP by their specific and overall compositions, respectively. To our knowledge, this was the first time that the E-nose, E-tongue, LC-HR-Q-TOF-MS/MS, and the Belousov-Zhabotinsky reaction were combined to identify AH and CP.

Results and discussion

With the E-nose, we identified 25 major odor components in AH and 12 odor components in CP in a single run of 140 s. Using the E-tongue, bitterness and astringency were identified as their primary taste differences. Furthermore, 91 compounds in AH and 90 compounds in CP were identified through LC-HR-Q-TOF-MS/MS. Both AH and CP shared nitrogenous compounds, volatile oils, organic acids, and lignans. However, AH uniquely contained coumarins and flavonoids, while CP contained steroidal compounds and saccharides. Notably, AH also possessed distinct toxic components, specifically aristolactam I, aristolochic acid D, and safrole. Based on the Belousov-Zhabotinsky reaction, we obtained the electrochemical fingerprint spectra of AH and CP, thereby facilitating further distinction between these two herbs. Through the combination of electrochemical fingerprint spectra with principal component analysis (PCA) or orthogonal partial least squares-discriminant analysis (OPLS-DA), the accuracy of this method reached 100%. Through the fusion strategy, the odors, tastes, components, and electrochemical properties of AH and CP have been systematically analyzed.

A perspective review on factors that influence mutagenicity in medicinal plants and their health implications

Medicinal plants are products from natural sources that have found relevance in medicine for several decades. They are rich in bioactive compounds; thus, they are widely used to treat different ailments globally. Medicinal plants have provided hope for the healthcare industry as most are used to synthesize modern medicines currently used in the treatment of various diseases. However, there are still concerns with respect to the mutagenic properties of medicinal plants. Over the years, researchers have embarked on various studies aimed at investigating the mutagenicity of several medicinal plants found in different regions of the world. In this review, we discussed factors that may influence plant mutagenicity and the findings of in vitro and in vivo mutagenicity studies of several medicinal plants from across the globe. In addition, this review considers the potential health implications of mutagenic medicinal plants and safety measures that can be used to mitigate mutagenesis in medicinal plants. To achieve this, we searched for articles reporting on medicinal plants and mutagenesis on the PubMed, Scopus, and Web of Science databases. Several journal articles reported on the mutagenicity of some medicinal plants; however, it was observed that the majority of the articles reported the nonmutagenicity of medicinal plants. The findings from these studies imply that medicinal plants have good prospects in treating diseases and that they are clinically relevant. However, these reports will require further validation to determine their safety for human use as limited in vivo studies were conducted and there are no clinical safety reports for any of the plants discussed in this review.

Emerging role of PANoptosis in kidney diseases: molecular mechanisms and therapeutic opportunities

Kidney diseases represent a significant global public health challenge, characterized by complex pathogenesis, high incidence, low awareness, insufficient early screening, and substantial treatment disparities. Effective therapeutic options remain lacking. Programmed cell death (PCD), including apoptosis, pyroptosis, and necroptosis, play pivotal roles in the pathogenesis of various kidney diseases. In 2019, PANoptosis, a novel form of inflammatory cell death, was introduced, providing new insights into innate immunity and PCD research. Although research on PANoptosis in kidney diseases is still limited, identifying key molecules within PANoptosomes and understanding their regulatory roles is critical for disease prevention and management. This review summarizes the various forms of PCD implicated in kidney diseases, along with PANoptosomes activated by Z-DNA binding protein 1 (ZBP1), absent in melanoma 2 (AIM2), receptor-interacting protein kinase 1 (RIPK1), NOD-like receptor family CARD domain containing 12 (NLRP12), and NOD-like receptor family member C5 (NLRC5). It also reviews the advancements in PANoptosis research in the field of kidney diseases, particularly in renal tumors and acute kidney injuries (AKI). The goal is to establish a foundation for future research into the role of PANoptosis in kidney diseases.

Aristolochic acid IVa ameliorates arthritis in SKG Mice by regulating macrophage polarization and Th17/Treg balance

BACKGROUND

Aristolochic acids (AAs)-containing herbs have been used as medicinal remedies for thousands of years. However, exposure to AAI and AAII increases the risk of nephropathy and cancers. Our previous study identified AAIVa, an analogue without carcinogenicity or nephrotoxicity, exerted anti-inflammatory effects.

PURPOSE

To explore AAIVa's anti-inflammatory mechanisms and assess its therapeutic potential in arthritis.

METHODS AND RESULTS

In this study, we employed in vitro assays on RAW 264.7 cells and explored the underlying mechanisms of AAIVa's anti-inflammatory effect through transcriptome analysis, identifying macrophage polarization-associated genes, IL-17 signaling, and Rheumatoid Arthritis (RA) pathway. Also, we used BALB/cAnSmoc-Zap70em(W163C)Smoc (SKG) mice, a model that spontaneously develops chronic arthritis closely resembling human RA, and revealed AAIVa's therapeutic potential in arthritis. AAIVa-treatment (10 mg/kg, i.g.) for 4 weeks protected SKG mice from mannan-accelerated arthritis symptoms, reducing inflammation and improving bone microstructure. We further isolated bone marrow-derived macrophages (BMDMs) and spleen primary cells from SKG and BALB/c mice to evaluate the impact of AAIVa on macrophage polarization and T cell differentiation. We found that AAIVa induced M2 macrophage polarization in BMDMs, and mitigated lipopolysaccharide-stimulated inflammation by increasing Tregs and decreasing Th17 cells. Subsequently, the elevation of M2 macrophages, increased Tregs expression and decreased Th17 cells in the ankle joints of SKG mice supported our in vitro observation.

CONCLUSION

We provide first evidence that AAIVa exerts anti-arthritis effects, likely through modulation of macrophage polarization and restoration of the Th17/Treg balance. Our findings highlight AAIVa's mechanism of action and AAIVa's potential as a therapeutic candidate for autoimmune arthritis.

Long-term oral administration of Kelisha capsule does not cause hepatorenal toxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Kelisha capsules (KLS) are often used to treat acute diarrhoea, bacillary dysentery, heat stroke, and other diseases. One of its components, Asarum, contains aristolochic acid I which is both nephrotoxic and carcinogenic. However, the aristolochic acid (AA) content in KLS and its toxicity remain unclear.

AIM OF THE STUDY

The aims of this study were to quantitatively determine the contents of five aristolochic acid analogues (AAAs) in Asarum and KLS, and systematically evaluate the in vivo toxicity of KLS in rats.

MATERIALS AND METHODS

Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the content of the five AAAs in Asarum and KLS. Sprague-Dawley rats were administered KLS at 0, 0.75, 1.5, and 3.0 g/kg respectively, and then sacrificed after 4 weeks of administration or after an additional 2 weeks of recovery. The endpoints assessed included body weight measurements, serum biochemistry and haematology indices, and clinical and histopathological observations.

RESULTS

The AAAs content in Asarum sieboldii Miq. (HB-ESBJ) were much lower than those of the other Asarums. The contents of AA I, AA IVa, and aristolactam I in KLS were in the ranges of 0.03-0.06 μg/g, 1.89-2.16 μg/g, and 0.55-1.60 μg/g, respectively, whereas AA II and AA IIIa were not detected. None of the rats showed symptoms of toxic reactions and KLS was well tolerated throughout the study. Compared to the control group, the activated partial thromboplastin time values of rats in the 1.5 and 3.0 g/kg groups significantly reduced after administration (P < 0.05). In addition, the serum triglycerides of male rats in the 0.75 and 1.5 g/kg groups after administration, and the 0.75, 1.5, 3.0 g/kg groups after recovery were significantly decreased (P < 0.01 or P < 0.001). No significant drug-related toxicological changes were observed in other serum biochemical indices, haematology, or histopathology.

CONCLUSIONS

The AA I content in KLS met the limit requirements (<0.001%) of the Chinese Pharmacopoeia. Therefore, it is safe to use KLS in the short-term. However, for safety considerations, attention should be paid to the effects of long-term KLS administration on coagulation function and triglyceride metabolism.

Unveiling correlations between aristolochic acids and liver cancer: spatiotemporal heterogeneity phenomenon

Aristolochic acids are a class of naturally occurring compounds in Aristolochiaceae that have similar structural skeletons and chemical properties. Exposure to aristolochic acids is a risk factor for severe kidney disease and urinary system cancer. However, the carcinogenicity of aristolochic acids to the liver, which is the main site of aristolochic acid metabolism, is unclear. Although the characteristic fingerprint of aristolochic acid-induced mutations has been detected in the liver and aristolochic acids are known to be hepatotoxic, whether aristolochic acids can directly cause liver cancer is yet to be verified. This review summarizes the findings of long-term carcinogenicity studies of aristolochic acids in experimental animals. We propose that spatiotemporal heterogeneity in the carcinogenicity of these phytochemicals could explain why direct evidence of aristolochic acids causing liver cancer has never been found in adult individuals. We also summarized the reported approaches to mitigate aristolochic acid-induced hepatotoxicity to better address the associated global safety issue and provide directions and recommendations for future investigation.

Activation of LONP1 by 84-B10 alleviates aristolochic acid nephropathy via re-establishing mitochondrial and peroxisomal homeostasis

Pharmaceutical formulations derived from Aristolochiaceae herbs, which contain aristolochic acids (AAs), are widely used for medicinal purposes. However, exposure to these plants and isolated AAs is linked to renal toxicity, known as AA nephropathy (AAN). Currently, the mechanisms underlying AAN are not fully understood, leading to unsatisfactory treatment strategies. In this study, we explored the protective role of 84-B10 (5-[[2-(4-methoxyphenoxy)-5-(trifluoromethyl) phenyl] amino]-5-oxo-3-phenylpentanoic acid) against AAN. RNA-seq analysis revealed that the mitochondrion and peroxisome were the most affected cellular components following 84-B10 treatment in AAN mice. Consistently, 84-B10 treatment preserved mitochondrial ultrastructure, restored mitochondrial respiration, enhanced the expression of key transporters (carnitine palmitoyltransferase 2) and enzymes (acyl-Coenzyme A dehydrogenase, medium chain) involved in mitochondrial fatty acid β-oxidation, and reduced mitochondrial ROS generation in both aristolochic acid I (AAI)-challenged mice kidneys and cultured proximal tubular epithelial cells. Additionally, 84-B10 treatment increased the expression of key transporters (ATP binding cassette subfamily D) and rate-limiting enzymes (acyl-CoA oxidase 1) involved in peroxisomal fatty acid β-oxidation and restored peroxisomal redox balance. Knocking down LONP1 expression diminished the protective effects of 84-B10 against AAN, suggesting LONP1-dependent protection. In conclusion, our study provides evidence that AAN is associated with significant disturbances in both mitochondrial and peroxisomal functions. The LONP1 activator 84-B10 demonstrates therapeutic potential against AAN, likely by maintaining homeostasis in both mitochondria and peroxisomes.

Long-term toxicity evaluation of aristolochic acid-IIIa in mice

Aristolochic acid (AA)-IIIa is an AA analog present in Aristolochiaceae plants. To evaluate the chronic toxicity of AA-IIIa, mice were intragastrically administered with media control, 1 mg/kg AA-IIIa, and 10 mg/kg AA-IIIa, and designated as the control (CTL), AA-IIIa low dose (AA-IIIa-L), and AA-IIIa high dose (AA-IIIa-H) groups, respectively. AA-IIIa was administered three times a week, every other day, for 24 weeks (24-week time point). Thereafter, some mice were sacrificed immediately, while others were sacrificed 29 or 50 weeks after AA-IIIa withdrawal (53- or 74-week time point). Serum and organs were collected for biochemical and pathological analyses, respectively. Whole-genome sequencing was performed on the kidney, liver, and stomach tissues of AA-IIIa-treated mice for single-nucleotide polymorphism (SNP) detection. AA-IIIa-H mice died at 66 weeks, and the remaining mice showed moribund conditions at the 69 weeks. AA-IIIa induced minor kidney tubule injury, fibroblast hyperplasia, and forestomach carcinoma in mice. Bladder, intestine, liver, heart, spleen, lung, and testis tissues were not pathologically altered by AA-IIIa. In addition, AA-IIIa increased the C:G > A:T mutation in the kidney; however, no SNP mutation changes were observed in the liver and forestomach tissues of AA-IIIa-H mice at the 24-week time point compared with control mice. Therefore, we suspect that AA-IIIa is potentially mutagenic for mice after overdose and long-term administration. On the other hand, the forestomach is a unique organ in mice, but it does not exist in humans; thus, we hypothesize that the stomach toxicity induced by AA-IIIa is not a suitable reference for toxicological evaluation in humans. We recommend that Aristolochiaceae plants containing AA-IIIa should be properly supervised, and overdosing and long-term administration of drugs containing AA-IIIa should be avoided.

Human UDP-glucuronosyltransferase 1As catalyze aristolochic acid D O-glucuronidation to form a lesser nephrotoxic glucuronide

ETHNOPHARMACOLOGICAL RELEVANCE

Aristolochic acids (AAs) are naturally occurring nitro phenanthrene carboxylic acids primarily found in plants of the Aristolochiaceae family. Aristolochic acid D (AAD) is a major constituent in the roots and rhizomes of the Chinese herb Xixin (the roots and rhizomes of Asarum heterotropoides F. Schmidt), which is a key material for preparing a suite of marketed Chinese medicines. Structurally, AAD is nearly identical to the nephrotoxic aristolochic acid I (AAI), with an additional phenolic group at the C-6 site. Although the nephrotoxicity and metabolic pathways of AAI have been well-investigated, the metabolic pathway(s) of AAD in humans and the influence of AAD metabolism on its nephrotoxicity has not been investigated yet.

AIM OF THE STUDY

To identify the major metabolites of AAD in human tissues and to characterize AAD O-glucuronidation kinetics in different enzyme sources, as well as to explore the influence of AAD O-glucuronidation on its nephrotoxicity.

MATERIALS AND METHODS

The O-glucuronide of AAD was biosynthesized and its chemical structure was fully characterized by both 1H-NMR and 13C-NMR. Reaction phenotyping assays, chemical inhibition assays, and enzyme kinetics analyses were conducted to assess the crucial enzymes involved in AAD O-glucuronidation in humans. Docking simulations were performed to mimic the catalytic conformations of AAD in human UDP-glucuronosyltransferases (UGTs), while the predicted binding energies and distances between the deprotonated C-6 phenolic group of AAD and the glucuronyl moiety of UDPGA in each tested human UGT isoenzyme were measured. The mitochondrial membrane potentials (MMP) and reactive oxygen species (ROS) levels in HK-2 cells treated with either AAI, or AAD, or AAD O-glucuronide were tested, to elucidate the impact of O-glucuronidation on the nephrotoxicity of AAD.

RESULTS

AAD could be rapidly metabolized in human liver and intestinal microsomes (HLM and HIM, respectively) to form a mono-glucuronide, which was purified and fully characterized as AAD-6-O-β-D-glucuronide (AADG) by NMR. UGT1A1 was the predominant enzyme responsible for AAD-6-O-glucuronidation, while UGT1A9 contributed to a lesser extent. AAD-6-O-glucuronidation in HLM, HIM, UGT1A1 and UGT1A9 followed Michaelis-Menten kinetics, with the Km values of 4.27 μM, 9.05 μM, 3.87 μM, and 7.00 μM, respectively. Docking simulations suggested that AAD was accessible to the catalytic cavity of UGT1A1 or UGT1A9 and formed catalytic conformations. Further investigations showed that both AAI and AAD could trigger the elevated intracellular ROS levels and induce mitochondrial dysfunction and in HK-2 cells, but AADG was hardly to trigger ROS accumulation and mitochondrial dysfunction.

CONCLUSION

Collectively, UGT1A-catalyzed AAD 6-O-glucuronidation represents a crucial detoxification pathway of this naturally occurring AAI analogs in humans, which is very different from that of AAI.

Histone deacetylase-mediated silencing of PSTPIP2 expression contributes to aristolochic acid nephropathy-induced PANoptosis

BACKGROUND AND PURPOSE

Aristolochic acid nephropathy (AAN) is a progressive kidney disease caused by using herbal medicines. Currently, no therapies are available to treat or prevent aristolochic acid nephropathy. Histone deacetylase (HDAC) plays a crucial role in the development and progression of renal disease. We tested whether HDAC inhibitors could prevent aristolochic acid nephropathy and determined the underlying mechanism.

EXPERIMENTAL APPROACH

HDACs expression in the aristolochic acid nephropathy model was examined. The activation of PANoptosis of mouse kidney and renal tubular epithelial cell were assessed after exposure to HDAC1 and HDAC2 blockade. Kidney-specific knock-in of proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) mice were used to investigate whether PSTPIP2 affected the production of PANoptosome.

KEY RESULTS

Aristolochic acid upregulated the expression of HDAC1 and HDAC2 in the kidneys. Notably, the HDAC1 and HDAC2 specific inhibitor, romidepsin (FK228, depsipeptide), suppressed aristolochic acid-induced kidney injury, epithelial cell pyroptosis, apoptosis and necroptosis (PANoptosis). Moreover, romidepsin upregulated PSTPIP2 in renal tubular epithelial cells, which was enhanced by aristolochic acid treatment. Conditional knock-in of PSTPIP2 in the kidney protected against aristolochic acid nephropathy. In contrast, the knockdown of PSTPIP2 expression in PSTPIP2-knock-in mice restored kidney damage and PANoptosis. PSTPIP2 function was determined in vitro using PSTPIP2 knockdown or overexpression in mouse renal tubular epithelial cells (mTECs). Additionally, PSTPIP2 was found to regulate caspase 8 in aristolochic acid nephropathy.

CONCLUSION AND IMPLICATIONS

HDAC-mediated silencing of PSTPIP2 may contribute to aristolochic acid nephropathy. Hence, HDAC1 and HDAC2 specific inhibitors or PSTPIP2 could be valuable therapeutic agents for preventing aristolochic acid nephropathy.

Detection and Removal of Aristolochic Acid in Natural Plants, Pharmaceuticals, and Environmental and Biological Samples: A Review

Aristolochic acids (AAs) are a toxic substance present in certain natural plants. Direct human exposure to these plants containing AAs leads to a severe and irreversible condition known as aristolochic acid nephropathy (AAN). Additionally, AAs accumulation in the food chain through environmental mediators can trigger Balkan endemic nephropathy (BEN), an environmental variant of AAN. This paper presents a concise overview of the oncogenic pathways associated with AAs and explores the various routes of environmental exposure to AAs. The detection and removal of AAs in natural plants, drugs, and environmental and biological samples were classified and summarized, and the advantages and disadvantages of the various methods were analyzed. It is hoped that this review can provide effective insights into the detection and removal of AAs in the future.

Generation of a high-affinity DNA aptamer for on-site screening of toxic aristolochic acid I in herbal medicines and botanical products

Aristolochic Acid I (AAI) is an environmental and foodborne toxin found in the Aristolochia and Asarum species of plants that are widespread all over the world. Therefore, there is an urgent need to develop a sensitive and specific biosensor for identifying AAI. Aptamers as a powerful biorecognition element provide the most viable options for solving this problem. In this study, we used library-immobilized SELEX to isolate an AAI-specific aptamer with a K_D value of 86 ± 13 nM. To verify the practicability of the selected aptamer, a label-free colorimetric aptasensor was designed. This aptasensor exhibited a low detection limit of 225 nM. Besides, it had been further applied for the determination of AAI in real samples and the recoveries ranged from 97.9% to 102.4%. In the future, AAI aptamer will provide a promising tool for safety evaluation in various fields of agriculture, food, and medication.

Differences in p38-STAT3-S100A11 signaling after the administration of aristolochic acid I and IVa may account for the disparity in their nephrotoxicity

BACKGROUND

The safety of herbs containing aristolochic acids (AAs) has become a widespread concern. Previous reports indicate that AAs are highly nephrotoxic and carcinogenic, although there are more than 170 analogues of aristolochic acid. Not all AAs have the same degree of nephrotoxicity or carcinogenicity. Previous studies have found that aristolochic acid IVa (AA-IVa), the principal component of AAs within members of the Aristolochiaceae family, especially Asarum, a commonly used herb in China, has essentially no significant nephrotoxicity. However, several studies, including ours, have shown that aristolochic acid I (AA-I) is clearly nephrotoxic.

PURPOSE

The focus of the study was to elucidate the molecular mechanism responsible for the difference in nephrotoxicity between the AA-I and AA-IVa.

STUDY DESIGN/METHOD

Mice were administered with AA-I or AA-IVa for 22 weeks through the oral route, followed by a 50-week recovery time. The kidney tissues of mice were extracted at the end of 22 weeks. Pathological examination and proteomic detection (tandem mass tagging (TMT) and phosphorylated proteomics) were performed on the kidney tissue to investigate the key signaling pathways and targets of AAs-induced renal interstitial fibrosis (RIF). The key signaling pathways and targets were verified by Western blot (WB), siRNA transfection, and luciferase assays.

RESULTS

AA-I caused severe nephrotoxicity, high mortality, and extensive RIF. However, the same AA-IVa dosage exhibited almost no nephrotoxicity and does not trigger RIF. The activation of the p38-STAT3-S100A11 signaling pathway and upregulated expression of α smooth muscle actin (α-SMA) and Bcl2-associated agonist of cell death (Bad) proteins could be the molecular mechanism underlying AA-I-induced nephrotoxicity. On the other hand, AA-IVa did not regulate the activation of the p38-STAT3-S100A11 signaling pathway and had relatively little effect on the expression of α-SMA and Bad. Consequently, the difference in the regulation of p38-STAT3-S100A11 pathway, α-SMA, and Bad proteins between AA-I and AA-IVa may be responsible for the divergence in their level of nephrotoxicity.

CONCLUSION

This is the first study to reveal the molecular mechanism underlying the difference in nephrotoxicity between AA-I and AA-IVa. Whether STAT3 is activated or not may be the key factor leading to the difference in nephrotoxicity between AA-I and AA-IVa.

Study on the difference and correlation between the contents and toxicity of aristolochic acid analogues in Aristolochia plants

ETHNOPHARMACOLOGICAL RELEVANCE

The nephrotoxicity and carcinogenicity induced by traditional Chinese medicines (TCMs) containing aristolochic acids (AAs) and related compound preparations have greatly limited their clinical application. While the toxicity of AA-I and AA-II is relatively clear, there are marked differences in the toxic effects of different types of aristolochic acid analogues (AAAs). Thus, the toxicity of TCMs containing AAAs cannot be evaluated based on the toxicity of a single compound.

AIM OF THE STUDY

To systematically investigate the toxicity induced by Zhushalian (ZSL), Madouling (MDL) and Tianxianteng (TXT) as representative TCMs derived from Aristolochia.

MATERIALS AND METHODS

AAA contents in ZSL, MDL and TXT were determined using HPLC. Subsequently, mice were treated for 2 weeks with high (H) and low (L) dosages of TCMs containing total AAA contents of 3 mg/kg and 1.5 mg/kg, respectively. Toxicity was evaluated using biochemical and pathological examination and was based on organ indices. Correlations between AAA contents and induced toxicity were analysed using multiple methods.

RESULTS

Of the total AAA content, ZSL contained mainly AA-I and AA-II (>90%, of which AA-I accounted for 49.55%). AA-I accounted for 35.45% in MDL. TXT mainly contained AA-IVa (76.84%) and other AAAs accounted for <10%. Short-term toxicity tests indicated that ZSL and high-dose MDL induced obvious renal interstitial fibrosis and gastric injury, whereas TXT (high and low dosages) caused only slight toxicity. Correlation analysis suggested that AA-I might be the critical hazard factor for toxicity.

CONCLUSIONS

The toxicity of TCMs containing AAAs cannot be generalised. The toxicity of TXT is relatively low compared with those of ZSL and MDL. The toxicity of Aristolochia depends mainly on the AA-I content; therefore, control of AA-I levels in TCMs and related compound preparations is required to reduce the risk of toxicity associated with the use of Aristolochia herbs in clinical settings.

Long-term oral administration of Asarum heterotropoides f. mandshuricum (Maxim.) Kitag. decoction and its aristolochic acid analogs do not cause renal toxicity in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Asarum heterotropoides f. mandshuricum (Maxim.) Kitag. (AH) is widely used to treat influenza, COVID-19, allergic rhinitis, headache, toothache, rheumatoid arthritis, and peptic ulcer. However, its clinical use is controversial due to the concern of aristolochic acid nephropathy (AAN) caused by its component aristolochic acid analogs (AAs).

AIM OF THE STUDY

The chronic toxicity of AH decoction and its main components AA IVa (AA-IVa) and aristolactam I (AL-I) was evaluated in mice.

MATERIALS AND METHODS

AAs contents in AH were quantitated by liquid chromatography-mass spectrometry. A parallel design was employed to examine the potential chronic toxicity of AH decoction at doses equivalent to 0.5, 1.6, and 5.0 g/kg AH (approximately 10-100 times the clinical doses for humans) and its major AA components at doses equivalent to that in 5.0 g/kg AH to mice after consecutive daily oral administration for 12 and 24 weeks, and at 32 weeks after withdrawal for 8 weeks.

RESULTS

AH crude herb contained 2.18 μg/g of AA-I, 48.49 μg/g of AA-IVa, and 14.0 μg/g of AL-I. AH decoction contained 5.45 μg/g of AA-IVa and 2.71 μg/g of AL-I. None of AA-II and AA-IIIa were detected in AH. After long-term administration of AH decoction and its major components AA-IVa and AL-I, mice showed no signs of illness or body weight changes. In addition, biochemical and pathohistological examinations showed that long-term administration of AH decoction and its major components AA-IVa and AL-I did not alter 1) serum levels of glutamic-pyruvic transaminase, glutamic oxalacetic transaminase, alkaline phosphatase, creatinine, and urea nitrogen, 2) renal tissue mRNA expression of kidney injury molecule 1 and neutrophil gelatinase-associated lipocalin, and 3) pathological morphology in the mouse liver, kidney, stomach, and bladder.

CONCLUSIONS

AH has no obvious toxicity to mice and is relatively safe when it is used in the form of decoction. AA-IVa and AL-I, the two major AAs in AH, are not toxic to mice at the dose equivalent to that in the high dose of AH decoction. Considering the limited toxicological data on AH, we recommend that AH decoction medication should not overdose and the duration should not be too long.

Non-carcinogenic/non-nephrotoxic aristolochic acid IVa exhibited anti-inflammatory activities in mice

Aristolochic acid (AA)-containing herbs have been prescribed for thousands of years as anti-inflammatory drugs, despite the active pharmaceutical ingredients remaining unclear. However, exposure to AAI and AAII has been proven to be a significant risk factor for severe nephropathy and carcinogenicity. AAIVa, an analogue abundant in AA-containing herbs, showed neither carcinogenicity nor nephrotoxicity in our study and other reports, implying that the pharmacological effects of AAIVa on inflammation are worth studying. Herein, we employed RAW 264.7 cells, the ear edema mouse model, and the lipopolysaccharide (LPS)-induced systematic inflammation model in TNF-IRES-Luc mice (tracking TNFα luciferase activities in real-time) to evaluate the anti-inframammary effect of AAIVa. Our results showed that AAIVa could decrease pro-inflammatory cytokines (TNFα and IL-6) production in LPS-stimulated RAW 264.7 cells, indicating its anti-inflammatory effects in vitro. Furthermore, the application of AAIVa (400 and 600 μg/ear) could significantly inhibit phorbol 12-myristate 13-acetate-induced ear edema, suggesting its topical anti-inflammatory activity in vivo. Moreover, LPS-stimulated TNF-IRES-Luc mice were used to investigate the onset and duration of AAIVa on systematic inflammation. A single dosage of AAIVa (100 mg/kg, i.g.) could suppress LPS-triggered inflammation, by decreasing luciferase activities of TNFα at 3 h in TNF-IRES-Luc mice. In addition, the online pharmacological databases predicted that AAIVa might target the regulation of T cell activation-related protein (ADA, ADORA2A, ERBB2) to exhibit anti-inflammatory effect. In conclusion, we demonstrated that AAIVa had anti-inflammatory effect for the first time; our findings are constructive for further studies on pharmacological mechanism of AAIVa.