Characterization of two CYP80 enzymes provides insights into aporphine alkaloid skeleton formation in Aristolochia contorta.

Aporphine alkaloids are a large group of natural compounds with extensive pharmaceutical application prospects. The biosynthesis of aporphine alkaloids has been paid attentions in the past decades. Here, we determined the contents of four 1-benzylisoquinoline alkaloids and five aporphine alkaloids in root, stem, leaf, and flower of Aristolochia contorta Bunge, which belongs to magnoliids. Two CYP80 enzymes were identified and characterized from A. contorta. Both of them catalyze the unusual C-C phenol coupling reactions and directly form the aporphine alkaloid skeleton. AcCYP80G7 catalyzed the formation of hexacyclic aporphine corytuberine. AcCYP80Q8 catalyzed the formation of pentacyclic proaporphine glaziovine. Kingdom-wide phylogenetic analysis of the CYP80 family suggested that CYP80 first appeared in Nymphaeales. The functional divergence of hydroxylation and C-C (or C-O) phenol coupling preceded the divergence of magnoliids and eudicots. Probable crucial residues of AcCYP80Q8 were selected through sequence alignment and molecular docking. Site-directed mutagenesis revealed two crucial residues E284 and Y106 for the catalytic reaction. Identification and characterization of two aporphine skeleton-forming enzymes provide insights into the biosynthesis of aporphine alkaloids.

Aristolochia mimics stink bugs to repel vertebrate herbivores via TRPA1 activation.

Mimicry is the phenomenon in which one species (the mimic) closely resembles another (the model), enhancing its own fitness by deceiving a third party into interacting with it as if it were the model. In plants, mimicry is used primarily to gain fitness by withholding rewards from mutualists or deterring herbivores cost-effectively. While extensive work has been documented on putative defence mimicry, limited investigation has been conducted in the field of chemical mimicry. In this study, we used field experiments, chemical analyses, behavioural assays, and electrophysiology, to test the hypothesis that the birthwort Aristolochia delavayi employs chemical mimicry by releasing leaf scent that closely resembles stink bug defensive compounds and repels vertebrate herbivores. We show that A. delavayi leaf scent is chemically and functionally similar to the generalized defensive volatiles of stink bugs and that the scent effectively deters vertebrate herbivores, likely through the activation of TRPA1 channels via (E)-2-alkenal compounds. This study provides an unequivocal example of chemical mimicry in plants, revealing intricate dynamics between plants and vertebrate herbivores. Our study underscores the potency of chemical volatiles in countering vertebrate herbivory, urging further research to uncover their potentially underestimated importance.

The complete chloroplast genome of Aristolochia fangchi provided insights into the phylogeny and species identification of Aristolochia.

Aristolochia fangchi is an important species within the family Aristolochiaceae, most of which contain nephrotoxic aristolochic acid. The inadvertent use of Aristolochiaceae plants as raw ingredients in the manufacturing of patent medicine poses a significant risk warranting considerable attention. In this study, we assembled and analyzed the complete chloroplast genome of Aristolochia fangchi, which is a 159 867 bp long circular molecule. Functional annotation of the A. fangchi plastome unveiled a total of 113 genes, including 79 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Subsequently, a series of genome structure and characteristic evaluations were conducted against the A. fangchi plastome. Further phylogenetic analysis suggested that a plausible phylogenetic relationship among Aristolochiaceae derived from the concatenated sequences of shared conserved genes rather than from the entire chloroplast genome with one IR copy. Finally, a DNA polymorphism assessment against a dozen Aristolochia plastomes yielded multiple potential regions for biomarker designation. Six pairs of primers were generated and underwent both in silico and actual PCR validations. In conclusion, this study identified the unique characteristics of the A. fangchi plastome, providing invaluable insights for further investigations on species identification and the phylogeny evolution between A. fangchi and its related species.

Combustion-Derived Pollutants Linked with Kidney Disease in Low-Lying Flood-Affected Areas in the Balkans.

Tens of thousands of people in southern Europe suffer from Balkan endemic nephropathy (BEN), and four times as many are at risk. Incidental ingestion of aristolochic acids (AAs), stemming from the ubiquitousAristolochia clematitis(birthwort) weed in the region, leads to DNA adduct-induced toxicity in kidney cells, the primary cause of BEN. Numerous cofactors, including toxic organics and metals, have been investigated, but all have shown small contributions to the overall BEN relative to non-BEN village distribution gradients. Here, we reveal that combustion-derived pollutants from wood and coal burning in Serbia also contaminate arable soil and test as plausible causative factors of BEN. Using a GC-MS screening method, biomass-burning-derived furfural and coal-burning-derived medium-chain alkanes were detected in soil samples from BEN endemic areas levels at up to 63-times and 14-times higher, respectively, than in nonendemic areas. Significantly higher amounts were also detected in colocated wheat grains. Coexposure studies with cultured kidney cells showed that these pollutants enhance DNA adduct formation by AA, - the cause of AA nephrotoxicity and carcinogenicity. With the coincidence of birthwort-derived AAs and the widespread practice of biomass and coal burning for household cooking and heating purposes and agricultural burning in rural low-lying flood-affected areas in the Balkans, these results implicate combustion-derived pollutants in promoting the development of BEN.

Aristolochia bracteolata flower extract based phytosynthesis and characterization of AgNPs: Antimicrobial, antidiabetic, and antioxidant activities potential assessment.

The study was carried out to evaluate the effectiveness of the Aristolochia bracteolata water flower extract-mediated AgNPs synthesis and assess their antimicrobial potential. According to the experimental and analytical results, A. bracteolata flower extract can produce valuable AgNPs. The characteristic features of these AgNPs were assessed with UV-visible spectrophotometer, Fourier transform-infrared spectroscopy, Transmission Electron Microscope, Scanning Electron Microscopy, as well as. Under UV-vis. spectrum results, showed major peak at 430 nm and recorded essential functional groups responsible for reducing, capping, and stabilizing AgNPs by FT-IR analysis. In addition, the size and shape of the synthesized AgNPs were found as 21.11-25.17 nm and spherical/octahedral shape. The A. bracteolata fabricated NPs showed remarkable antimicrobial activity against fish bacterial pathogens (V. parahaemolytics, Serratia sp., B. subtilis, and E. coli) as well as common fungal pathogens (A. niger, C. albicans, A. flavus, and A. terreus) at the quantity of 100 µg mL-1 than positive controls. Nevertheless, it was not effective against human bacterial pathogens. It concludes that AgNPs synthesized from A. bracteolata aqueous flower extract have excellent antimicrobial activity and may have a variety of biomedical applications.

Genetic diversity assessment and biotechnological aspects in Aristolochia spp.

Aristolochia, belonging to the family Aristolochiaceae, has immense ecological significance due to its large size and huge geographic distribution. In the context of dealing with a genus with a huge number of species like Aristolochia, these markers come in handy to precisely identify a particular species and enumerate the genetic diversity. Also, certain species of Aristolochia are economically important due to the presence of secondary metabolites and vast use in traditional and modern medicine. But, the presence of profitable biochemical constituents in Aristolochia is very low and the breeding process of the plant is highly dependable on pollinators. Hence, identifying different biotechnological approaches to fasten the reproductive cycle of Aristolochia and increase the secondary metabolites is of great interest to the researchers. In this study, a comprehensive review has been established on different types of morphological/anatomical markers (starch grains with "Maltese cross"), phytochemical markers (aristolochic acid, triterpenoid, aristolactam etc.) and genetic markers (ISSR, SSR, DNA bar-coding) for various Aristolochia spp. We have also discussed the applications of different biotechnological tools in Aristolochia spp. which include discrete approaches to promote in vitro germination, in vitro shooting, root induction, somatic embryogenesis, synthetic seed production, acclimatization and hardening and sustainable production of secondary metabolites. In a nutshell, the present review is a first of kind approach to comprehensively demonstrate the genetic diversity studies and biotechnological aspects in Aristolochia spp. KEY POINTS: • Insights into the in vitro propagation of Aristolochia spp. • In vitro production and optimization of secondary metabolites. • Assessment of genetic diversity by molecular markers.

[Risk assessment, safe medication and scientific supervision of traditional Chinese medicine containing aristolochic acids--toxicity is different among aristolochic acids, and detection and control of aristolochic acid â /â ¡ is critical].

The safety problem of traditional Chinese medicine containing aristolochic acid is of great concern in China and abraod, which poses a challenge in clinical application and supervision. There are many types of aristolochic acid analogues(AAAs) and 178 have been reported. According to the structure, they are classified into aristolochic acids(AAs) and aristololactams(ALs). The toxi-city is remarkably different among AAAs of different types. For example, AA-Ⅰ has strong nephrotoxicity and carcinogenicity, and the toxicity of AA-Ⅱ is lower than that of AA-Ⅰ. Besides, AA-Ⅳa and AA-Ⅰa are considered to have no obvious nephrotoxicity and carcinogenicity. The types and content of AAAs are significantly different among traditional Chinese medicines derived from different Aristolochiaceae species. For example, Asari Radix et Rhizoma and Aristolochiae Herba mainly consist of AAAs without obvious toxicity(such as AA-Ⅳa). The content of AAAs in compound preparations is related to the proportions of the medicinals and the processing method. The content of AA-Ⅰ in some compound preparations is very low or below the detection limit. Therefore, the author concludes that AAAs of different types have different toxicity, but not all AAAs has nephrotoxicity and carcinogenicity. Moreover, the toxicity of traditional Chinese medicines containing AAAs should not be generalized and AA-Ⅰ and AA-Ⅱ should be emphasized. In this paper, it is suggested that traditional Chinese medicine containing AAAs should be used rationally and research, analysis, and toxicological study of AAAs species and content should be strengthened. In addition, limit standards of AA-Ⅰ and AA-Ⅱ should be formulated and science-based supervision should be performed.

Rapid characterization and pharmacokinetic study of aristolochic acid analogues using ion mobility mass spectrometry.

Aristolochic acid analogues (AAAs), naturally existing in herbal Aristolochia and Asarum genera, were once widely used in traditional pharmacopeias because of their anti-inflammatory properties, but lately they were identified as potential nephrotoxins and mutagens. A method for rapid characterization of AAAs in serum was developed using ion mobility spectrometry coupled with mass spectrometry (IMS-MS). Five AAAs, containing four aristolochic acids and one aristolactam, were separated and identified within milliseconds. AAAs were separated in gas phase based on the difference of their ion mobility (K0), and then identified based on their K0 values, m/z, and product ions from MS/MS. Quantitative analysis of AAAs was performed using an internal standard with a satisfactory sensitivity. Limits of detection (signal-to-noise = 3) and quantification (signal-to-noise = 10) were 1-5 ng/mL and 3-8 ng/mL, respectively. The method was validated and successfully applied to the pharmacokinetics study of AAAs in rats, offering a promising way for fast screening and evaluation of AAAs in biological samples.

Tolerance of Novel Toxins through Generalized Mechanisms: Simulating Gradual Host Shifts of Butterflies.

Organisms encounter a wide range of toxic compounds in their environments, from chemicals that serve anticonsumption or anticompetition functions to pollutants and pesticides. Although we understand many detoxification mechanisms that allow organisms to consume toxins typical of their diet, we know little about why organisms vary in their ability to tolerate entirely novel toxins. We tested whether variation in generalized stress responses, such as antioxidant pathways, may underlie variation in reactions to novel toxins and, if so, their associated costs. We used an artificial diet to present cabbage white butterfly caterpillars (Pieris rapae) with plant material containing toxins not experienced in their evolutionary history. Families that maintained high performance (e.g., high survival, fast development time, large body size) on diets containing one novel toxic plant also performed well when exposed to two other novel toxic plants, consistent with a generalized response. Variation in constitutive (but not induced) expression of genes involved in oxidative stress responses was positively related to performance on the novel diets. While we did not detect reproductive trade-offs of this generalized response, there was a tendency to have less melanin investment in the wings, consistent with the role of melanin in oxidative stress responses. Taken together, our results support the hypothesis that variation in generalized stress responses, such as genes involved in oxidative stress responses, may explain the variation in tolerance to entirely novel toxins and may facilitate colonization of novel hosts and environments.

Determination of Aristolochic Acids in Vegetables: Nephrotoxic and Carcinogenic Environmental Pollutants Contaminating a Broad Swath of the Food Supply and Driving Incidence of Balkan Endemic Nephropathy.

Balkan endemic nephropathy (BEN) is a slowly progressive interstitial fibrotic disease affecting numerous people living along the Danube River in the Balkan Peninsula, of which aristolochic acids (AAs) produced naturally in Aristolochia plants are key etiological agents. However, the exposure biology of the disease remains poorly understood. Initially, the high incidence of BEN in the Balkan Peninsula was thought to occur through ingestion of bread prepared from flour made with wheat grains comingled with the seeds of Aristolochia clematitis L., an AA-containing weed that grows abundantly in the wheat fields of the affected areas. In this study, by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, we show for the first time that vegetables, in particular root vegetables of endemic areas, are extensively contaminated with AAs taken up through root absorption from the AA-tainted soil. Furthermore, we found a pH dependence of the n-octanol/water partition coefficient (Kow) of AAs, which resulted in a dramatically higher hydrophobicity-driven plant uptake efficiency of AAs into food crops in endemic areas, characterized by higher acidity levels, compared to non-endemic areas. We believe the results of this study have significantly unraveled the mystery surrounding the uneven distribution of BEN incidence.

Liquid chromatography-tandem mass spectrometry analysis of aristolochic acids in soil samples collected from Serbia: Link to Balkan endemic nephropathy.

RATIONALE: Over the past six decades, residents of farming villages in multiple countries of the Balkan peninsula have been suffering from a unique type of chronic renal disease, Balkan endemic nephropathy (BEN). It was speculated that environmental pollution by aristolochic acids (AAs) produced naturally by Aristolochia clematitis L., a weed that grows in the area, was causing the disease. However, the human exposure pathway to this class of phytotoxin remains obscure. Knowledge of the sink and stability of AAs in the environment would assist in the formulation of policy reducing exposure risk. METHODS: Using our newly developed liquid chromatography/tandem mass spectrometry method of high sensitivity and selectivity, we analysed over 130 soil samples collected from cultivation fields in southern Serbia for the presence of AAs. The environmental stability of AAs was also investigated by incubating soil samples spiked with AAs at various temperatures. RESULTS: The analysis detected AA-I in over two-fifths of the tested samples at sub-µg/kg to µg/kg levels, with higher concentrations observed in more acidic farmland soil. Furthermore, analysis of soil samples incubated at various temperatures revealed half-lives of over 2 months, indicating that AAs are relatively resistant to degradation. CONCLUSIONS: Cultivation soil in southern Serbia is being extensively contaminated with AAs released from the decomposition of A. clematitis weeds. Since AAs are resistant to degradation, it is possible that AAs could have been taken up by root absorption and transported to the edible part of food crops. Prolonged exposure to AA-contaminated food grown from polluted soil could be one of the main aetiological mechanisms of BEN observed in the area.

Biotransformation and Toxicities of Aristolochic Acids.

Environmental and iatrogenic exposures contribute significantly to human diseases, including cancer. The list of known human carcinogens has recently been extended by the addition of aristolochic acids (AAs). AAs occur primarily in Aristolochia herbs, which are used extensively in folk medicines, including Traditional Chinese Medicine. Ingestion of AAs results in chronic renal disease and cancer. Despite importation bans imposed by certain countries, herbal remedies containing AAs are readily available for purchase through the internet. With recent advancements in mass spectrometry, next generation sequencing, and the development of integrated organs-on-chips, our knowledge of cancers associated with AA exposure, and of the mechanisms involved in AA toxicities, has significantly improved. DNA adduction plays a central role in AA-induced cancers; however, significant gaps remain in our knowledge as to how cellular enzymes promote activation of AAs and how the reactive species selectively bind to DNA and kidney proteins. In this review, I describe pathways for AAs biotransformation, adduction, and mutagenesis, emphasizing novel methods and ideas contributing to our present understanding of AA toxicities in humans.

Two New Aristolochic Acid Analogues from the Roots of Aristolochia contorta with Significant Cytotoxic Activity.

Twelve compounds, including two new aristolochic acid analogues with a formyloxy moiety (9-10) and 10 known aristolochic acid derivates (1-8 and 11-12), were obtained from the roots of Aristolochiacontorta. Their structures were elucidated using extensive spectroscopic methods. Their cytotoxic activity in human proximal tubular cells HK-2 was evaluated by the MTT method, which has been widely used to assess cell viability. Among these molecules, compounds 3 and 9 were found to be more cytotoxic. Furthermore, molecular modeling was used to evaluate, for the first time, the interactions of compounds 3 and 9 with the target protein organic anionic transporter 1 (OAT1) that plays a key role in mediating aristolochic acid nephropathy. Structure-activity relationships are briefly discussed.

Antinociceptive Effect of Hinokinin and Kaurenoic Acid Isolated from Aristolochia odoratissima L.

Aristolochia odoratissima L. is employed for the treatment of pain and as an antidote against the poison of venomous animals in traditional medicine. However, reports have not been found, to our knowledge, about the evaluation of the antinociceptive activity of extracts nor about the presence of compounds associated with this activity. Thus, the purpose of this work was to evaluate the antinociceptive activity of extracts and compounds isolated from the stems of Artistolochia odoratissima L. The extracts were obtained with solvents of increasing polarity and the compounds were isolated and characterized by column chromatography, HPLC, and NMR. The antinociceptive activity was carried out by the formalin test in mice. Ethyl acetate (AoEA) and methanolic (AoM) extracts decreased the paw licking in both phases of the formalin test. The isolated compounds (kaurenoic acid and hinokinin) from AoEA showed the highest antinociceptive activity in both phases of the formalin test. These results confirmed the analgesic effect of this specie described in traditional medicine and provided a base for a novel analgesic agent. They also allowed an approach for the development of standardized plant extracts with isolated metabolites.

Aristolochia Herbs and Iatrogenic Disease: The Case of Portland's Powders.

Aristolochia herbals have a 2500-year history of medicinal use. We focused this article on Portland's Powders, an 18th-century British gout medicine containing Aristolochia herbs. The powders constitute an 18th-century iteration of an herbal remedy, which was used, with variations, since at least the fifth century BCE. The use of Portland's Powders in Great Britain may appear to be an unusual choice for investigating a public health problem currently widespread in Asia. Yet it exemplifies long-term medicinal use of Aristolochia herbs, reflecting our argument that aristolochic acid nephropathy (AAN) is a historically persistent iatrogenic disease. Moreover, we provide compelling evidence that individuals taking Portland's Powders for gout would have ingested toxic quantities of aristolochic acid, which causes AAN and cancer. Several factors, including long history of use, latency of toxic effects, and lack of effective regulation, perpetuate usage of Aristolochia herbals to the present day.

Genome-wide transcriptional analysis of Aristolochia manshuriensis induced gastric carcinoma.

Context: Aristolochia manshuriensis Kom (Aristolochiaceae) (AMK) is known for toxicity and mutagenicity.Objective: The tumorigenic role of AMK has yet to be understood.Materials and methods: AMK extracts were extracted from root crude drug. SD (Sprague Dawley) rats underwent gavage with AMK (0.92 g/kg) every other day for 10 (AMK-10) or 20 (AMK-20) weeks. Stomach samples were gathered for histopathological evaluation, microarray and mRNA analysis.Results: The gastric weight to body weight ratio (GW/BW) is 1.7 in the AMK-10 cohort, and 1.8 in AMK-20 cohort compared to control (CTL) cohort. Liver function was damaged in AMK-10 and AMK-20 rats compared to CTL rats. There were no significant changes of CRE (creatinine) in AMK-10 and AMK-20 rats. Histopathological analysis revealed that rats developed dysplasia in the forestomach in AMK-10 rats, and became gastric carcinoma in AMK-20 rats. Genes including Mapk13, Nme1, Gsta4, Gstm1, Jun, Mgst2, Ggt6, Gpx2, Gpx8, Calml3, Rasgrp2, Cd44, Gsr, Dgkb, Rras, and Amt were found to be critical in AMK-10 and AMK-20 rats. Pik3cb, Plcb3, Tp53, Hras, Myc, Src, Akt1, Gnai3, and Fgfr3 worked in AMK-10 rats, and PDE2a and PDE3a played a pivotal role in AMK-20 rats.Discussion and conclusions: AMK induced benign or malignant gastric tumours depends on the period of AMK administration. Genes including Mapk13, Nme1, Gsta4, Gstm1, Jun, Mgst2, Ggt6, Gpx2, Gpx8, Calml3, Rasgrp2, Cd44, Gsr, Dgkb, Rras, Amt, Pik3cb, Plcb3, Tp53, Hras, Myc, Src, Akt1, Gnai3, Fgfr3, PDE2a, and PDE3a were found to be critical in aristolochic acid-induced gastric tumour process.

Quantitation of DNA Adducts in Target and Nontarget Organs of Aristolochic Acid I-Exposed Rats: Correlating DNA Adduct Levels with Organotropic Activities.

Chronic exposure to aristolochic acids (AAs) from Aristolochia plants is one of the major causes of nephropathy and cancer of the kidney and forestomach. However, the organotropic activities of AAs remain poorly understood. In this study, using LC-MS/MS coupled with a stable isotope-dilution method, we rigorously quantitated for the first time the organ-specific dosage- and time-dependent formation of DNA-AA adducts in the tumor target and nontarget organs of AA-I-treated rats. The results support the proposal that the DNA adduct level is a major contributor to the observed organotropic activities of AAs.

Isolation of aristolochic acid I from herbal plant using molecular imprinted polymer composited ionic liquid-based zeolitic imidazolate framework-67.

Aristolochic acid I is a toxic compound found in the genus of Aristolochia plants, which are commonly used as herbal cough treatment medicines. To remove the aristolochic acid I in extract efficiently and selectively, a molecularly imprinted polymer composed of ethylimidazole ionic liquid-based zeolitic imidazolate framework-67 was synthesized and used as the adsorbent. Under the conditions optimized by the software design expert, the sorbent showed highest adsorption amount of 34.25 mg/g in methanol/water (95:5, v/v) at 39°C for 138 min. The sorbent was then applied to solid phase extraction to isolate aristolochic acid I from the extract of the herbal plant Fibraurea Recisa Pierre. 0.043 mg/g of aristolochic acid I was obtained after the loading, washing, and elution processes. The limit of detection of 2.41 × 10-5  mg/mL and good recoveries provided evidence for the accuracy of this method.

Chemical Constituents and Pharmacology properties of Aristolochia triangularis: a south brazilian highly-consumed botanical with multiple bioactivities.

Aristolochia triangularis Cham., is one of the most frequently used medicinal plant in Southern Brazil. Preparations containing the leaves and/or stems are traditionally used as anti-inflammatory, diuretic, as well as antidote against snakebites. This study screened A. triangularis extracts, fractions and isolated compounds for different bioactivities. A weak antiproliferative activity against human lung cancer cell line (A549) was observed only for chloroform fraction obtained from stems (CFstems - CC50: 2.93 µg/mL). Also, a moderate antimicrobial activity against Staphylococcus aureus was detected just for chloroform fraction obtained from leaves (CFleaves -13-16 mm inhibition zone). Additionally, two semi-purified fractions (CFstems-4 and CFleaves-4) selectively inhibited HSV-1 replication (IC50 values of 0.40 and 2.61 µg/mL, respectively), while only CFleaves showed promising results against Leishmania amazonensis. Fractionation of extracts resulted in the isolation of one neolignan (-) cubebin and one lignan (+) galbacin. However, these compounds are not responsible for the in vitro bioactivities herein detected. The presence of aristolochic acid I and aristolochic acid II in the crude ethanol extract of stems (CEEstems) and leaves (CEEleaves) was also investigated. The HPLC analysis of these extracts did not display any peak with retention time or UV spectra comparable to aristolochic acids I and II.

(+)-Isobicyclogermacrenal and spathulenol from Aristolochia yunnanensis alleviate cardiac fibrosis by inhibiting transforming growth factor ß/small mother against decapentaplegic signaling pathway.

Cardiac fibrosis contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. Antifibrotic therapies are likely to be a crucial strategy in curbing many fibrosis-related cardiac diseases. In our previous study, an ethyl acetate extract of a traditional Chinese medicine Aristolochia yunnanensis Franch. was found to have a therapeutic effect on myocardial fibrosis in vitro and in vivo. However, the exact chemicals and their mechanisms responsible for the activity of the crude extract have not been illustrated yet. In the current study, 10 sesquiterpenoids (1-10) were isolated from the active extract, and their antifibrotic effects were systematically evaluated in transforming growth factor ß 1 (TGFß1)-stimulated cardiac fibroblasts and NIH3T3 fibrosis models. (+)-Isobicyclogermacrenal (1) and spathulenol (2) were identified as the main active components, being more potent than the well-known natural antifibrotic agent oxymatrine. Compounds 1 and 2 could inhibit the TGFß1-induced cardiac fibroblasts proliferation and suppress the expression of the fibrosis biomarkers fibronectin and α-smooth muscle actin via down-regulation of their mRNA levels. The mechanism study revealed that 1 and 2 could inhibit the phosphorylation of TGFß type I receptor, leading to the decrease of the phosphorylation levels of downstream Smad2/3, then consequently blocking the nuclear translocation of Smad2/3 in the TGFß/Smad signaling pathway. These findings suggest that 1 and 2 may serve as promising natural leads for the development of anticardiac fibrosis drugs.