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.

Chemotaxonomy of the ethnic antidote Aristolochia indica for aristolochic acid content: Implications of anti-phospholipase activity and genotoxicity study.

ETHNOPHARMACOLOGICAL RELEVANCE: Aristolochia indica L. (Aristolochiaceae) is a common medicinal plant described in many traditional medicine as well as in Ayurveda used against snakebites. Besides, the plant has also been reported traditionally against fever, rheumatic arthritis, madness, liver ailments, dyspepsia, oedema, leishmaniasis, leprosy, dysmenorrhoea, sexual diseases etc. The plant is known to contain its major bioactive constituent aristolochic acid (AA) known for its anti-snake venom, abortifacient, antimicrobial and antioxidant properties. MATERIALS AND METHODS: This present work describes a validated, fast and reproducible high performance thin layer chromatography (HPTLC) method to estimate AA from the roots of 20 chemotypes of A. indica procured from 20 diverse geographical locations from the state of West Bengal, India. Further, an evidence-based approach was adopted to investigate the reported anti-venom activity of the aqueous extracts of the A. indica roots by assessing its phospholipase A2 (PLA2) inhibitory properties since PLA2 is a major component of many snake-venoms. Finally, the cytotoxicity and genotoxicity of the aqueous root extract of the Purulia (AI 1) chemotype were assessed at various concentrations using Allium cepa root meristematic cells. RESULTS: The highest amount of AA (7643.67 µg/g) was determined in the roots of A. indica chemotype collected from Purulia district followed by the chemotypes collected from Murshidabad, Jalpaiguri and Birbhum districts (7398.34, 7345.09 and 6809.97 µg/g respectively). This study not only determines AA in the plants to select pharmacologically elite chemotypes of A. indica, but it also identifies high AA producing A. indica for further domestication and propagation of the plants for pharmacological and industrial applications. The method was validated via analyzing inter-day and intra-day precision, repeatability, reproducibility, instrumental precision, limit of detection (LOD) and limit of quantification (LOQ) and specificity. Chemotypes with high AA content exhibited superior anti-PLA2 activity by selectively inhibiting human-group PLA2. Moreover, A. indica root extract significantly inhibited mitosis in Allium cepa root tips as a potent clastogen. CONCLUSIONS: The present quick, reproducible and validated HPTLC method provides an easy tool to determine AA in natural A. indica plant populations as well as in food and dietary supplements, a potential antivenin at one hand and a possible cause of aristolochic acid nephropathy (AAN) at another. Besides, the cytotoxic and mitotoxic properties of the root extracts should be used with caution especially for oral administration.

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.

Aristolochic acid mutational signature defines the low-risk subtype in upper tract urothelial carcinoma.

Rationale: Dietary exposure to aristolochic acids and similar compounds (collectively, AA) is a significant risk factor for nephropathy and subsequent upper tract urothelial carcinoma (UTUC). East Asian populations, who have a high prevalence of UTUC, have an unusual genome-wide AA-induced mutational pattern (COSMIC signature 22). Integrating mutational signature analysis with clinicopathological information may demonstrate great potential for risk ranking this UTUC subtype. Methods: We performed whole-genome sequencing (WGS) on 90 UTUC Chinese patients to extract mutational signatures. Genome sequencing data for urinary cell-free DNA from 26 UTUC patients were utilized to noninvasively identify the mutational signatures. Genome sequencing for primary tumors on 8 out of 26 patients was also performed. Metastasis-free survival (MFS) and cancer-specific survival (CSS) were measured using Kaplan-Meier methods. Results: Data analysis showed that a substantial proportion of patients harbored the AA mutational signature and were associated with AA-containing herbal drug intake, female gender, poor renal function, and multifocality. Field cancerization was found to partially contribute to multifocality. Nevertheless, AA Sig subtype UTUC patients exhibited favorable outcomes of CSS and MFS compared to the No-AA Sig subtype. Additionally, AA Sig subtype patients showed a higher tumor mutation burden, higher numbers of predicted neoantigens, and infiltrating lymphocytes, suggesting the potential for immunotherapy. We also confirmed the AA signature in AA-treated human renal tubular HK-2 cells. Notably, the AA subtype could be ascertained using a clinically applicable sequencing strategy (low coverage) in both primary tumors and urinary cell-free DNA as a basis for therapy selection. Conclusion: The AA mutational signature as a screening tool defines low-risk UTUC with therapeutic relevance. The AA mutational signature, as a molecular prognostic marker using either ureteroscopy and/or urinary cell-free DNA, is especially useful for diagnostic uncertainty when kidney-sparing treatment and/or immune checkpoint inhibitor therapy were considered.

Aristolochic Acid Affects Upper Tract Urothelial Cancer Behavior through the MAPK Pathway.

The prevalence of upper tract urothelial carcinoma (UTUC) in Taiwan is relatively higher than thatin Western countries. Aristolochic acid (AA), which is widely used in traditional Chinese herbology, is now recognized to be one of the carcinogens for UTUC. Numerous UTUC patients have chronic kidney diseases or end-stage renal diseases; however, little literature hasreported on theoncogenic pathway of AA-related UTUC. The aim of our study was to identify the potential target treatment for AA-related UTUC. Here, we established an AA pre-exposure followed bya 3-methylcholanthrene (MCA) stimulus tumorigenic cell model. We not only demonstrated that AA pre-exposure MCA stimulus tumorigenic cells have more behaviors of cell migration and invasion by enhancing the metalloproteinases (MMP) activity, which is compatible with clinical findings of AA-related UTUC, but we also validated that AA pre-exposure MCA stimulus tumorigeniccells could be activated through the mitogen-activated protein kinases (MAPK) pathway. We further dissected the route of the MAPK pathway and found that the p38 and extracellular signal regulated kinases (ERK) sub-pathways might play essential roles in AA pre-exposure urothelial cancer cell lines. This consequence was also corroborated with a tissue study in AA-exposed patients.

Marcanine G, a new cytotoxic 1-azaanthraquinone from the stem bark of Goniothalamus marcanii Craib.

The ethanolic extract from the stem bark of Goniothalamus marcanii Craib was shown in preliminary brine shrimp lethality data having good cytotoxic activity. Further bioassay guided isolation was done by means of solvent partition, chromatography and precipitation to provide four isolated compounds: a novel compound 1 with the core structure of 1-azaanthraquinone moiety referred as marcanine G; as well as compounds 2-4 with known aristolactam structures namely, piperolactam C, cepharanone B and taliscanine. These compounds were characterised by spectroscopic techniques. The assessment of cytotoxicity was established on an SRB assay using doxorubicin as a positive control. Marcanine G (1) was considered the most active compound indicating the IC50 values of 14.87 and 15.18 µM against human lung cancer cells (A549) and human breast cancer cells (MCF7), respectively. However, 2 showed mild activity with the IC50 values of 83.72 and 82.32 µM against A549 and MCF7 cells, respectively.

Aristolochic Acid in the Etiology of Renal Cell Carcinoma.

BACKGROUND: Aristolochia species used in the practice of traditional herbal medicine contains aristolochic acid (AA), an established human carcinogen contributing to urothelial carcinomas of the upper urinary tract. AA binds covalently to genomic DNA, forming aristolactam (AL)-DNA adducts. Here we investigated whether AA is also an etiologic factor in clear cell renal cell carcinoma (ccRCC). METHODS: We conducted a population-based case-control study to investigate the linkage between Aristolochia prescription history, cumulative AA consumption, and ccRCC incidence in Taiwan (5,709 cases and 22,836 matched controls). The presence and level of mutagenic dA-AL-I adducts were determined in the kidney DNA of 51 Taiwanese ccRCC patients. The whole-exome sequences of ccRCC tumors from 10 Taiwanese ccRCC patients with prior exposure to AA were determined. RESULTS: Cumulative ingestion of more than 250 mg of AA increased risk of ccRCC (OR, 1.25), and we detected dA-AL-I adducts in 76% of Taiwanese ccRCC patients. Furthermore, the distinctive AA mutational signature was evident in six of 10 sequenced ccRCC exomes from Taiwanese patients. CONCLUSIONS: This study strongly suggests that AA contributes to the etiology of certain RCCs. IMPACT: The current study offers compelling evidence implicating AA in a significant fraction of the RCC arising in Taiwan and illustrates the power of integrating epidemiologic, molecular, and genetic data in the investigation of cancer etiology. Cancer Epidemiol Biomarkers Prev; 25(12); 1600-8. ©2016 AACR.

Discovery of Dual ETA/ETB Receptor Antagonists from Traditional Chinese Herbs through in Silico and in Vitro Screening.

Endothelin-1 receptors (ETAR and ETBR) act as a pivotal regulator in the biological effects of ET-1 and represent a potential drug target for the treatment of multiple cardiovascular diseases. The purpose of the study is to discover dual ETA/ETB receptor antagonists from traditional Chinese herbs. Ligand- and structure-based virtual screening was performed to screen an in-house database of traditional Chinese herbs, followed by a series of in vitro bioassay evaluation. Aristolochic acid A (AAA) was first confirmed to be a dual ETA/ETB receptor antagonist based intracellular calcium influx assay and impedance-based assay. Dose-response curves showed that AAA can block both ETAR and ETBR with IC50 of 7.91 and 7.40 µM, respectively. Target specificity and cytotoxicity bioassay proved that AAA is a selective dual ETA/ETB receptor antagonist and has no significant cytotoxicity on HEK293/ETAR and HEK293/ETBR cells within 24 h. It is a feasible and effective approach to discover bioactive compounds from traditional Chinese herbs using in silico screening combined with in vitro bioassay evaluation. The structural characteristic of AAA for its activity was especially interpreted, which could provide valuable reference for the further structural modification of AAA.

Aristolochic acid, a plant extract used in the treatment of pain and linked to Balkan endemic nephropathy, is a regulator of K2P channels.

BACKGROUND AND PURPOSE: Aristolochic acid (AristA) is found in plants used in traditional medicines to treat pain. We investigated the action of AristA on TREK and TRESK, potassium (K2P) channels, which are potential therapeutic targets in pain. Balkan endemic nephropathy (BEN) is a renal disease associated with AristA consumption. A mutation of TASK-2 (K2P 5.1) channels (T108P) is seen in some patients susceptible to BEN, so we investigated how both this mutation and AristA affected TASK-2 channels. EXPERIMENTAL APPROACH: Currents through wild-type and mutated human K2P channels expressed in tsA201 cells were measured using whole-cell patch-clamp recordings in the presence and absence of AristA. KEY RESULTS: TREK-1- and TREK-2-mediated currents were enhanced by AristA (100 µM), whereas TRESK was inhibited. Inhibition of TRESK did not depend on the phosphorylation of key intracellular serines but was completely blocked by mutation of bulky residues in the inner pore (F145A_F352A). The TASK-2_T108P mutation markedly reduced both current density and ion selectivity. A related mutation (T108C) had similar but less marked effects. External alkalization and application of flufenamic acid enhanced TASK-2 and TASK-2_T108C current but did not affect TASK-2_T108P current. AristA (300 µM) produced a modest enhancement of TASK-2 current. CONCLUSIONS AND IMPLICATIONS: Enhancement of TREK-1 and TREK-2 and inhibition of TRESK by AristA may contribute to therapeutically useful effects of this compound in pain. Whilst AristA is unlikely to interact directly with TASK-2 channels in BEN, loss of functional TASK-2 channels may indirectly increase susceptibility to AristA toxicity.

Differentiation between two "fang ji" herbal medicines, Stephania tetrandra and the nephrotoxic Aristolochia fangchi, using hyperspectral imaging.

Stephania tetrandra ("hang fang ji") and Aristolochia fangchi ("guang fang ji") are two different plant species used in Traditional Chinese Medicine (TCM). Both are commonly referred to as "fang ji" and S. tetrandra is mistakenly substituted and adulterated with the nephrotoxic A. fangchi as they have several morphological similarities. A. fangchi contains aristolochic acid, a carcinogen that causes urothelial carcinoma as well as aristolochic acid nephropathy (AAN). In Belgium, 128 cases of AAN was reported while in China, a further 116 cases with end-stage renal disease were noted. Toxicity issues associated with species substitution and adulteration necessitate the development of reliable methods for the quality assessment of herbal medicines. Hyperspectral imaging in combination with partial least squares discriminant analysis (PLS-DA) is suggested as an effective method to distinguish between S. tetrandra and A. fangchi root powder. Hyperspectral images were obtained in the wavelength region of 920-2514nm. Reduction of the dimensionality of the data was done by selecting the discrimination information range (964-1774nm). A discrimination model with a coefficient of determination (R(2)) of 0.9 and a root mean square error of prediction (RMSEP) of 0.23 was created. The constructed model successfully identified A. fangchi and S. tetrandra samples inserted into the model as an external validation set. In addition, adulteration detection was investigated by preparing incremental adulteration mixtures of S. tetrandra with A. fangchi (10-90%). Hyperspectral imaging showed the ability to accurately predict adulteration as low as 10%. It is evident that hyperspectral imaging has tremendous potential in the development of visual quality control methods which may prevent cases of aristolochic acid nephropathy in the future.

LC-MS- and (1)H NMR-Based Metabolomic Analysis and in Vitro Toxicological Assessment of 43 Aristolochia Species.

Species of Aristolochia are used as herbal medicines worldwide. They cause aristolochic acid nephropathy (AAN), a devastating disease associated with kidney failure and renal cancer. Aristolochic acids I and II (1 and 2) are considered to be responsible for these nephrotoxic and carcinogenic effects. A wide range of other aristolochic acid analogues (AAAs) exist, and their implication in AAN may have been overlooked. An LC-MS- and (1)H NMR-based metabolomic analysis was carried out on 43 medicinally used Aristolochia species. The cytotoxicity and genotoxicity of 28 Aristolochia extracts were measured in human kidney (HK-2) cells. Compounds 1 and 2 were found to be the most common AAAs. However, AA IV (3), aristolactam I (4), and aristolactam BI (5) were also widespread. No correlation was found between the amounts of 1 or 2 and extract cytotoxicity against HK-2 cells. The genotoxicity and cytotoxicity of the extracts could be linked to their contents of 5, AA D (8), and AA IIIa (10). These results undermine the assumption that 1 and 2 are exclusively responsible for the toxicity of Aristolochia species. Other analogues are likely to contribute to their toxicity and need to be considered as nephrotoxic agents. These findings facilitate understanding of the nephrotoxic mechanisms of Aristolochia and have significance for the regulation of herbal medicines.

Prediction and Characterisation of the System Effects of Aristolochic Acid: A Novel Joint Network Analysis towards Therapeutic and Toxicological Mechanisms.

Aristolochic acid (AA) is the major active component of medicinal plants from the Aristolochiaceae family of flowering plants widely utilized for medicinal purposes. However, the molecular mechanisms of AA systems effects remain poorly understood. Here, we employed a joint network analysis that combines network pharmacology, a protein-protein interaction (PPI) database, biological processes analysis and functional annotation analysis to explore system effects. Firstly, we selected 15 protein targets (14 genes) in the PubChem database as the potential target genes and used PPI knowledge to incorporate these genes into an AA-specific gene network that contains 129 genes. Secondly, we performed biological processes analysis for these AA-related targets using ClueGO, some of new targeted genes were randomly selected and experimentally verified by employing the Quantitative Real-Time PCR assay for targeting the systems effects of AA in HK-2 cells with observed dependency of concentration. Thirdly, the pathway-based functional enrichment analysis was manipulated using WebGestalt to identify the mostly significant pathways associated with AA. At last, we built an AA target pathway network of significant pathways to predict the system effects. Taken together, this joint network analysis revealed that the systematic regulatory effects of AA on multidimensional pathways involving both therapeutic action and toxicity.

Structural Basis for the Inhibition of a Phospholipase A2-Like Toxin by Caffeic and Aristolochic Acids.

One of the main challenges in toxicology today is to develop therapeutic alternatives for the treatment of snake venom injuries that are not efficiently neutralized by conventional serum therapy. Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability. This leads to economic and social problems, especially in developing countries. In this work, we performed structural and functional studies with Piratoxin-I, a Lys49-PLA2 from Bothropspirajai venom, complexed with two compounds present in several plants used in folk medicine against snakebites. These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane. Our results corroborate the previously proposed mechanism of action of PLA2s-like and provide insights for the design of structure-based inhibitors that could prevent the permanent injuries caused by these proteins in snakebite victims.

Metabolomic Responses of Human Hepatocytes to Emodin, Aristolochic Acid, and Triptolide: Chemicals Purified from Traditional Chinese Medicines.

The present study was undertaken to investigate the metabolic responses of human liver cells HL-7702 on chemicals purified from traditional Chinese medicine: emodin, triptolide, and aristolochic acid. Cytotoxicity tests demonstrated a dose-dependent toxic effect of emodin, triptolide, and aristolochic acid on HL7702 cells for 48 h. Emodin (14 µM), aristolochic acid (12 µg/mL), or triptolide (18 nM) was individually administrated to HL7702 and cell samples were collected after 48 h for metabolites extraction and analysis. Pattern recognition analysis reflected the significant difference in metabolic profiles between chemical-treated groups and the control group. Finally, eight metabolites including N1 -acetylspermidine, Glu Gly, N-undecanoylglycine, C16 sphinganine, sphinganine, glutathione, l-palmitoylcarnitine, and elaidic carnitine were detected as potential common biomarkers. Three pathways including sphinganine metabolism, fatty acid oxidation, and oxidative stress were identified. Our findings indicated that metabolomics would be an efficient approach to understand the molecular mechanism of hepatotoxicity induced by chemicals.

Non-aristolochic acid prescribed Chinese herbal medicines and the risk of mortality in patients with chronic kidney disease: results from a population-based follow-up study.

OBJECTIVES: To evaluate the relationship between the use of non-aristolochic acid (AA) prescribed Chinese herbal medicines (CHMs) and the risk of mortality in patients with chronic kidney disease (CKD). DESIGN: Nationwide population-based follow-up study. SETTING: Longitudinal health insurance database sampled from the Taiwan National Health Insurance Research Database. PARTICIPANTS: A total of 47 876 patients with CKD were identified. Participants who had ever used AA-containing CHMs, had cancer or HIV prior to the diagnosis of CKD, died within the first month of CKD diagnosis and who were not Taiwanese citizens were excluded. A total of 13 864 participants were eligible for final analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: All-cause mortality among patients with CKD between 2000 and 2008. RESULTS: After controlling for potential confounders, we found that participants who started to receive non-AA prescribed CHMs after the diagnosis of CKD had a lower risk of mortality as compared with non-users of non-AA prescribed CHMs (adjusted HR (aHR) 0.6; 95% CI 0.4 to 0.7, p<0.001). Moreover, participants who had used non-AA prescribed CHMs prior to and after the diagnosis of CKD also had a lower risk of mortality than non-users (aHR 0.6; 95% CI 0.5 to 0.8, p<0.001). In subgroup analyses, we found that such an inverse association was present only among patients who were not eligible to receive erythropoietin therapy (ie, serum creatinine ≦6 mg/dL and/or haematocrit value ≧28%). CONCLUSIONS: Patients who received non-AA prescribed CHMs after the diagnosis of CKD, yet before the start of erythropoietin therapy had a lower risk of mortality than those who did not.

A novel p53 mutant found in iatrogenic urothelial cancers is dysfunctional and can be rescued by a second-site global suppressor mutation.

Exposure to herbal remedies containing the carcinogen aristolochic acid (AA) has been widespread in some regions of the world. Rare A→T TP53 mutations were recently discovered in AA-associated urothelial cancers. The near absence of these mutations among all other sequenced human tumors suggests that they could be biologically silent. There are no cell banks with established lines derived from human tumors with which to explore the influence of the novel mutants on p53 function and cellular behavior. To investigate their impact, we generated isogenic mutant clones by integrase-mediated cassette exchange at the p53 locus of platform (null) murine embryonic fibroblasts and kidney epithelial cells. Common tumor mutants (R248W, R273C) were compared with the AA-associated mutants N131Y, R249W, and Q104L. Assays of cell proliferation, migration, growth in soft agar, apoptosis, senescence, and gene expression revealed contrasting outcomes on cellular behavior following introduction of N131Y or Q104L. The N131Y mutant demonstrated a phenotype akin to common tumor mutants, whereas Q104L clone behavior resembled that of cells with wild-type p53. Wild-type p53 responses were restored in double-mutant cells harboring N131Y and N239Y, a second-site rescue mutation, suggesting that pharmaceutical reactivation of p53 function in tumors expressing N131Y could have therapeutic benefit. N131Y is likely to contribute directly to tumor phenotype and is a promising candidate biomarker of AA exposure and disease. Rare mutations thus do not necessarily point to sites where amino acid exchanges are phenotypically neutral. Encounter with mutagenic insults targeting cryptic sites can reveal specific signature hotspots.

The safety of Homnawakod herbal formula containing Aristolochia tagala Cham. in Wistar rats.

BACKGROUND: A dried root of Aristolochia tagala Cham. (ATC) is often used in Thai traditional medicine as an antipyretic, anti-inflammatory agent, muscle relaxant, appetite-enhancing agent, and analeptic. Homnawakod, an important herbal recipe, originally contains ATC in its formula, however, some Aristolochia species have been reported to cause nephrotoxicity due to aristolochic acid (AA) and its derivatives, resulting in ATC removal from all formulae. Therefore, this study investigates the chemical profiles of ATC, the original (HNK+ATC) and the present Homnawakod Ayurved Siriraj Herbal Formulary™ (HNK), and investigates whether they could cause nephrotoxicity or aggravate LPS-induced organ injuries in vivo. METHODS: HPLC and LC/MS were used for chemical profile study. Male Wistar rats were randomly divided into groups in which the rats were intragastrically administered distilled water (2 groups), ATC (10 or 30 mg/kg), HNK+ATC (540 or 1,620 mg/kg), or HNK (1,590 mg/kg) for 21 days. A positive control group was administered with single dose 100 mg/kg standard AA-I intragastrically at day 1. Serum creatinine and urea were measured at baseline and at 7, 14 and 21 days of the treatment. On day 22, a model of lipopolysaccharide (LPS)-induced endotoxemia was used. One-way and two-way analyses of variance were performed and a P value of less than 0.05 was considered to be significant. RESULTS: The similarity of the HPLC chromatograms of HNK+ATC and HNK could suggest that the qualities of both formulae are nearly the same in terms of chemical profile. The amount of AA-I found in ATC is 0.24%w/w. All experimental groups exhibited similar levels of serum urea at baseline and 7 and 14 days of the treatment. At 21 days, rats received AA exhibited a significant increase in serum urea, whereas the others did not exhibit such toxicity. On day 22, there were no significant changes in LPS-induced renal and liver dysfunction, or LPS-induced mean arterial pressure (MAP) reduction upon administration of ATC, HNK+ATC, HNK or AA-I. CONCLUSIONS: These results suggest that ATC, HNK+ATC or HNK, at the animal dose equivalent to that used in human, do not cause the acute nephrotoxicity in rats and do not aggravate LPS-induced organ injuries even further.

Harpalycin 2 inhibits the enzymatic and platelet aggregation activities of PrTX-III, a D49 phospholipase A2 from Bothrops pirajai venom.

BACKGROUND: Harpalycin 2 (HP-2) is an isoflavone isolated from the leaves of Harpalyce brasiliana Benth., a snakeroot found in northeast region of Brazil and used in folk medicine to treat snakebite. Its leaves are said to be anti-inflammatory. Secretory phospholipases A2 are important toxins found in snake venom and are structurally related to those found in inflammatory conditions in mammals, as in arthritis and atherosclerosis, and for this reason can be valuable tools for searching new anti-phospholipase A2 drugs. METHODS: HP-2 and piratoxin-III (PrTX-III) were purified through chromatographic techniques. The effect of HP-2 in the enzymatic activity of PrTX-III was carried out using 4-nitro-3-octanoyloxy-benzoic acid as the substrate. PrTX-III induced platelet aggregation was inhibited by HP-2 when compared to aristolochic acid and p-bromophenacyl bromide (p-BPB). In an attempt to elucidate how HP-2 interacts with PrTX-III, mass spectrometry, circular dichroism and intrinsic fluorescence analysis were performed. Docking scores of the ligands (HP-2, aristolochic acid and p-BPB) using PrTX-III as target were also calculated. RESULTS: HP-2 inhibited the enzymatic activity of PrTX-III (IC50 11.34 ± 0.28 µg/mL) although it did not form a stable chemical complex in the active site, since mass spectrometry measurements showed no difference between native (13,837.34 Da) and HP-2 treated PrTX-III (13,856.12 Da). A structural analysis of PrTX-III after treatment with HP-2 showed a decrease in dimerization and a slight protein unfolding. In the platelet aggregation assay, HP-2 previously incubated with PrTX-III inhibited the aggregation when compared with untreated protein. PrTX-III chemical treated with aristolochic acid and p-BPB, two standard PLA2 inhibitors, showed low inhibitory effects when compared with the HP-2 treatment. Docking scores corroborated these results, showing higher affinity of HP-2 for the PrTX-III target (PDB code: 1GMZ) than aristolochic acid and p-BPB. HP-2 previous incubated with the platelets inhibits the aggregation induced by untreated PrTX-III as well as arachidonic acid. CONCLUSION: HP-2 changes the structure of PrTX-III, inhibiting the enzymatic activity of this enzyme. In addition, PrTX-III platelet aggregant activity was inhibited by treatment with HP-2, p-BPB and aristolochic acid, and these results were corroborated by docking scores.

A fluorescence-based analysis of aristolochic acid-derived DNA adducts.

Aristolochic acids (AAs), major components of plant extracts from Aristolochia species, form (after metabolic activation) pro-mutagenic DNA adducts in renal tissue. The DNA adducts can be used as biomarkers for studies of AA toxicity. Identification of these adducts is a complicated and time-consuming procedure. We present here a fast, nonisotopic, fluorescence-based assay for the detection of AA-DNA adducts in multiple samples. This approach allows analysis of AA adducts in synthetic DNA with known nucleotide composition and analysis of DNA adducts formed from chemically diverse AAs in vitro. The method can be applied to compare AA-DNA adduct formation in cells and tissues.

A new aristolactam-type alkaloid from the roots of Aristolochia fangchi.

Phytochemical investigation of 85% ethanol extracts from the roots of Aristolochia fangchi yielded a new aristolactam derivative named 6-methoxyl aristolactam I N-ß-glucoside (1), together with four known compounds, aristolactam IVa (2), aristolactam I-ß-D-glucoside (3), aristolactam I (4), and aristolactam-N-ß-D-glucoside (5). Their structures were elucidated by spectral analysis. The cytotoxicity of the isolated compounds was also determined.