Analysis of aristolochic acids in Houttuynia cordata by liquid chromatography-tandem mass spectrometry

Chemical profiling of principle active and toxic constituents in herbs containing aristolochic acids

Objective

To clear the amounts of the principal active/toxic components in herbs containing aristolochic acids (HCAAs), which are still used as medicine and/or seasoning in many ethnic minority areas of China.

Methods

In this study, six major active and toxic components in HCAAs were extracted with ultrasonic extraction. With 6-O-methyl guanosine as internal standard, the target compounds were analyzed qualitatively and quantitatively by using ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) with multiple reaction monitoring-information dependent acquisition-enhanced production ion scanning mode (MRM-IDA-EPI) combined with dynamic background subtraction (DBS) function.

Results

The method showed good linearity in the linear range of the six analytes. The limit range of detection was from 0.01 ng/mL to 0.27 ng/mL. All of the detection repeatability, extraction repeatability and accuracy of the method were good. After extraction, the samples remained stable at 15 °C within 24 h. Six analytes were all found in samples except aristolactam (AL) in sample 2, and the contents varied greatly. The contents of these compounds decreased in fruits, leaves and stems of Aristolochia delavayi successively.

Conclusion

This method has the advantages of less sample dosage, simple operation, short analysis cycle, high sensitivity, specificity and accuracy. It laid a good foundation for guiding the safety of HCAAs, the in-depth study of pharmacological and toxicological effects and the scientific and standardized processing and compatibility of HCAAs.

Rapid and selective removal of aristolochic acid I in natural products by vinylene-linked iCOF resins

Rapid, efficient, and selective removal of toxicants such as aristolochic acid I (AAI) from complex natural product systems is of great significance for the safe use of herbal medicines or medicine-food plants. Addressing this challenge, we develop a high-performance separation approach based on ionic covalent organic frameworks (iCOFs) to separate and remove AAI. Two vinylene-linked iCOFs (NKCOF-46-Br- and NKCOF-55-Br-) with high crystallinity are fabricated in a green and scalable fashion via a melt polymerization synthesis method. The resulting materials exhibit a uniform morphology, high stability, fast equilibrium time, and superior affinity and selectivity for AAI. Compared to conventional separation media, NKCOF-46-Br- and NKCOF-55-Br- achieve the record high adsorption capacities of 246.0 mg g-1 and 178.4 mg g-1, respectively. Various investigations reveal that the positively charged framework and favorable pore microenvironment of iCOFs contribute to their high selectivity and adsorption efficiency. Moreover, the iCOFs exhibit excellent biocompatibility by in vivo toxicity assays. This study paves a new avenue for the rapid, selective and efficient removal of toxicants from complex natural systems.

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.

Comparative Analysis of Aristolochic Acids in Aristolochia Medicinal Herbs and Evaluation of Their Toxicities

Aristolochic acids (AAs) are a group of nitrophenanthrene carboxylic acids present in many medicinal herbs of the Aristolochia genus that may cause irreversible hepatotoxicity, nephrotoxicity, genotoxicity and carcinogenicity. However, the specific profile of AAs and their toxicity in Aristolochia plants, except for AAs Ι and ΙΙ, still remain unclear. In this study, a total of 52 batches of three medicinal herbs belonging to the Aristolochia family were analyzed for their AA composition profiles and AA contents using the UPLC-QTOF-MS/MS approach. The studied herbs were A. mollissima Hance (AMH), A. debilis Sieb.etZucc (ADS), and A. cinnabaria C.Y.Cheng (ACY). Chemometrics methods, including PCA and OPLS-DA, were used for the evaluation of the Aristolochia medicinal herbs. Additionally, cytotoxicity and genotoxicity of the selected AAs and the extracts of AMH and ADS were evaluated in a HepG2 cell line using the MTT method and a Comet assay, respectively. A total of 44 AAs, including 23 aristolochic acids and 21 aristolactams (ALs), were detected in A. mollissima. Moreover, 41 AAs (23 AAs and 18 ALs) were identified from A. debilis Sieb, and 45 AAs (29 AAs and 16 ALs) were identified in A. cinnabaria. Chemometrics results showed that 16, 19, and 22 AAs identified in AMH, ADS, and ACY, respectively, had statistical significance for distinguishing the three medicinal herbs of different origins. In the cytotoxicity assay, compounds AL-BΙΙ, AAΙ and the extract of AMH exhibited significant cytotoxicities against the HepG2 cell line with the IC₅₀ values of 0.2, 9.7 and 50.2 μM, respectively. The results of the Comet assay showed that AAΙ caused relatively higher damage to cellular DNA (TDNA 40-95%) at 50 μM, while AAΙΙ, AMH and ADS extracts (ranged from 10 to 131 μM) caused relatively lower damage to cellular DNA (TDNA 5-20%).

Uptake, Translocation, and Fate of Carcinogenic Aristolochic Acid in Typical Vegetables in Soil-Plant Systems

When Aristolochia plants wilt and decay, aristolochic acids (AAs) are released into the soil, causing soil contamination. It has been demonstrated that aristolochic acid can be accumulated and enriched in crops through plant uptake. However, there is a lack of systematic studies on the migration and accumulation of AAs in a realistic simulated soil environment. In this study, Aristolochia herbal extracts were mixed with soil for growing three typical vegetables: lettuce, celery, and tomato. The contents of AAs in the above-mentioned plants were determined by an established highly sensitive LC-MS/MS method to study the migration and accumulation of AAs. We found that AAs in the soil can be transferred and accumulated in plants. AAs first entered the roots, which were more likely to accumulate AAs, and partially entered the above-ground parts. This further confirms that AAs can enter the food chain through plants and can have serious effects on human health. It was also shown that plants with vigorous growth and a large size absorbed AAs from the soil at a faster rate. The more AAs present in the soil, the more they accumulated in the plant.

The Traditional Chinese Medicine Houttuynia cordata Thunb decoction alters intestinal barrier function via an EGFR dependent MAPK (ERK1/2) signalling pathway

BACKGROUND

A traditionally prepared aqueous extract (= decoction) of Houttuynia cordata Thunb (Yu xing cao) (HC) is widely used in Traditional Chinese Medicine (TCM) to treat inflammatory disease. Previous chemical and biological studies on HC have mainly focused on organic extracts rather than the aqueous decoction, which is the traditional formulation.

PURPOSE

The study aimed to investigate whether the chemical composition of HC aqueous decoction (HCD) varies with geographical sourcing, to investigate the mechanism of action of HCD, and to determine if chemical variation impacts on HCDs anti-inflammatory activity.

METHOD

Sixteen samples of HC were purchased from Sichuan, Hubei and Anhui provinces in the People's Republic of China (PRC) and were prepared by the traditional decoction method to yield their corresponding HCDs. A Quality Control (QC) sample was prepared by combining individual HCD extracts. HCDs were analysed by Nuclear Magnetic Resonance (NMR) and High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS). The anti-inflammatory activities associated with intestinal barrier function of HCD were studied by tumor necrosis factor-α (TNF-α) activated Caco-2 monolayers in vitro and in vivo using Dextran Sulfate Sodium (DSS)-induced murine colitis. Proteins involved in inflammation, mRNA levels, disease severity scores, and histology involved in intestinal inflammation were analysed.

RESULTS

HCD samples exhibited different chemical fingerprints and three regional outliers were identified by Principal Component Analysis (PCA). Fifteen phytochemical metabolites were identified and quantified. HCD showed in vitro anti-inflammatory activity, enhancing zonula occludens-1 (ZO-1), occludin, interleukin (IL)-10 and decreasing IL-1β, IL-6 and epidermal growth factor receptor (EGFR) via an EGFR-dependent mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 1/2 (ERK 1/2) signaling pathway. This beneficial effect on intestinal inflammation was also seen in the in vivo colitis model at a molecular level in colonic tissues.

CONCLUSION

This study shows that the test HCDs were chemically different, resulting in different levels of activity on intestinal barrier function and inflammation. Moreover, a "Daodi" product showed the greatest biological activity in this study, thus validating the importance of the "Daodi" quality material in TCM and supporting the traditional used of HCD for the treatment of inflammation.

Antiosteoporosis Studies of 20 Medicine Food Homology Plants Containing Quercetin, Rutin, and Kaempferol: TCM Characteristics, In Vivo and In Vitro Activities, Potential Mechanisms, and Food Functions

Dietary nutraceutical compounds have been evidenced as backbone for bone health in recent years. It is reported that medicine food homology (MFH) plants have multiple nutraceutical compounds. Based on our literature research, 20 MFH plants caught our attention because they contain three popular antiosteoporosis compounds simultaneously: quercetin, rutin, and kaempferol. According to traditional Chinese medicine (TCM), their characteristics including natures, flavors, attributive to meridian tropism, and efficacies were listed. The relationships between TCM efficacies, such as “heat clearing,” “tonic,” and “the interior warming,” and antiosteoporosis pharmacological actions such as antioxidant and immune regulation were discussed. The in vivo antiosteoporosis effects of the 20 MFH plants were summarized. The in vitro antiosteoporosis activities and related mechanisms of the 20 plants and quercetin, rutin, kaempferol were detailed. The TGF-β-Smad signaling, fibroblast growth factor, and Wnt/β-catenin signaling on bone formation and the RANKL signaling, NF-κB signaling, and macrophage-colony-stimulating factor on bone resorption were identified. From food point, these 20 MFH plants could be classified as condiment, vegetable, fruit, tea and related products, beverage, etc. Based on the above discussion, these 20 MFH plants could be used as daily food supplements for the prevention and treatment against osteoporosis.

Study of the Contents of Analogues of Aristolochic Acid in Houttuynia cordata by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

In this study, a new and simple method was established for the simultaneous determination of analogues of aristolochic acids (aristolochic acid I, aristolochic acid II, aristolactam I and aristolactam AII) in Houttuynia cordata by ultra-high performance liquid chromatography–quadrupole/time-of-flight mass spectrometry (UHPLC–Q/TOF-MS). The samples were ultrasonically extracted with methanol, purified with HC-C18, and then separated on a C18 column (75 × 2.1 mm, 2.0 μm) at 35 °C. Under the optimized conditions, aristolochic acid I (AA-I), aristolochic acid II (AA-II), aristolactam I (AL-I) and aristolactam AII (AL-AII) all showed good linear regression (not less than 0.9987). The average recoveries of the four analytes were within the range of 72.3–105.5%, with the relative standard deviations (RSDs) being ≤7.6%. The proposed method was then applied to the determination of Houttuynia cordata samples collected from different regions in China. The results showed that none of the three carcinogenic substances (aristolochic acid I, aristolochic acid II and aristolactam I) were detected in any of the 22 samples collected from 22 different regions of China, while aristolactam AII, which has not been reported to have genotoxicity, was detected in all samples. This study provides a valuable reference for the further safety assessment of Houttuynia cordata.