Differentiation of herbs linked to “Chinese herb nephropathy” from the liquid chromatographic determination of aristolochic acids

Identification of serum metabolites associated with aristolochic acid nephropathy severity and insights into the underlying mechanism

Aristolochic acid nephropathy (AAN) is a rapidly progressive kidney disease caused by medical or environmental exposure to aristolochic acids (AAs). This study aimed to identify serum metabolites associated with the severity of acute AAN and investigate the underlying mechanisms. Male C57BL/6 mice were treated with vehicle and 3 doses of aristolochic acid I (AAI) (1.25, 2.5, and 5 mg/kg/d) for 5 days by intraperitoneal injection. The results showed that AAI dose-dependently increased blood urea nitrogen (BUN) and serum creatinine (Scr) levels and renal pathological damage. Non-targeted metabolomics revealed that differences in serum metabolite profiles from controls increased with increasing AAI doses. Compared with the control group, 56 differentially expressed metabolites (DEMs) that could be affected by all 3 doses of AAI were obtained. We further identified 13 DEMs whose abundance significantly correlated with Scr and BUN levels and had good predictive values for diagnosing AAI exposure. Among the 13 DEMs, lipids and lipid-like molecules constituted the majority. Western blotting found that AAI suppressed renal fatty acid oxidation (FAO)-related enzymes expression. In conclusion, these findings provided evidence for developing biomarkers for monitoring AAs exposure and AAN diagnosis and indicated activation of FAO as a potential direction for the treatment of AAN.

Aristolochic Acid Exposure via Dermal Contact or Inhalation of Herbal Powders: Evidence of Occupational Exposure in Herbalists with Urothelial Cancer

Emerging evidence showing urothelial cancer in herbalists is linked to aristolochic acid (AA) exposure; however, the exposure pathway remains unclear. Here, we show that dermal contact and inhalation of fine powders of AA-containing herbs are significant occupational AA exposure pathways for herbalists. We initiated the study by quantifying the amount of AA in the AA-containing powder deposited on gloves and face masks worn by the operators of an AA-containing herb grinding machine. Then, we measured the kinetics of dermal absorption and dissolution of AA from fine powders of AA-containing herbs into artificial sweat and surrogate lung fluid. Lastly, we quantified the mutagenic AA-DNA adduct levels formed in the kidneys of mice exposed to AA-containing fine powders through dermal contact. Our findings highlight an urgent occupational risk that should demand implementation of safety standards for herbalists exposed to AA-containing fine powders.

Multifunctional Eu(III)-modified HOFs: roxarsone and aristolochic acid carcinogen monitoring and latent fingerprint identification based on artificial intelligence

The exploration of multifunctional materials and intelligent technologies used for fluorescence sensing and latent fingerprint (LFP) identification is a research hotspot of material science. In this study, an emerging crystalline luminescent material, Eu3+-functionalized hydrogen-bonded organic framework (Eu@HOF-BTB, Eu@1), is fabricated successfully. Eu@1 can emit purple red fluorescence with a high photoluminescence quantum yield of 36.82%. Combined with artificial intelligence (AI) algorithms including support vector machine, principal component analysis, and hierarchical clustering analysis, Eu@1 as a sensor can concurrently distinguish two carcinogens, roxarsone and aristolochic acid, based on different mechanisms. The sensing process exhibits high selectivity, high efficiency, and excellent anti-interference. Meanwhile, Eu@1 is also an excellent eikonogen for LFP identification with high-resolution and high-contrast. Based on an automatic fingerprint identification system, the simultaneous differentiation of two fingerprint images is achieved. Moreover, a simulation experiment of criminal arrest is conducted. By virtue of the Alexnet-based fingerprint analysis platform of AI, unknown LFPs can be compared with a database to identify the criminal within one second with over 90% recognition accuracy. With AI technology, HOFs are applied for the first time in the LFP identification field, which provides a new material and solution for investigators to track criminal clues and handle cases efficiently.

Aristolochic acid-associated urinary tract cancers: an updated meta-analysis of risk and oncologic outcomes after surgery and systematic review of molecular alterations observed in human studies

BACKGROUND

The risk of primary aristolochic acid (AA)-associated urothelial carcinoma (AA-UC) has been summarized by a 2013-published meta-analysis. Given that additional evidence has been continuously reported by original studies, an updated meta-analysis is needed. Meanwhile, to complete the whole picture, a systematic review of molecular alterations observed in AA-urinary tract cancers (AA-UTC) was also performed.

METHODS

We searched PubMed, Embase and four Chinese databases up to October 2020. Observational studies comparing risk or oncologic outcomes of UTC between patients with and without AA exposure were eligible for systematic review and meta-analysis. Studies investigating molecular alterations in AA-UTC using human tissue samples were eligible for systematic review.

RESULTS

In total, 38 and 20 studies were included in the systematic review and meta-analysis, respectively. Exposure to AA led to an overall increased risks of primary UTC [UC and renal cell carcinoma (RCC)] (OR 6.085, 95% CI 3.045-12.160) and postoperatively recurrent UC (RR 1.831, 95% CI 1.528-2.194). Subgroup analysis of postoperative primary AA-upper tract UC (AA-UTUC) showed increased risks of bladder recurrence (adjusted RR 1.949, 95% CI 1.462-2.597) and contralateral UTUC recurrence (crude RR 3.760, 95% CI 2.225-6.353), worse overall survival (adjusted HR 2.025, 95% CI 1.432-2.865) and worse disease-specific survival (adjusted HR 3.061, 95% CI 1.190-7.872), but no effect on cancer-specific survival (adjusted HR 0.772, 95% CI 0.269-2.215). High mutation load with AA mutational signature presenting largely in the putative driver genes was observed in AA-UTUC. In contrast, AA mutational signature is rarely found in the mutated RCC driver genes and the mutation load in AA-RCC is low. Therefore, AA has different roles in the genesis of UTUC and RCC.

CONCLUSIONS

Implementing effective strategies to completely protect people from exposure to AA is urgently needed. Additionally, more effort should be made in identifying the precise carcinogenic mechanisms of AA to determine the future treatment strategies.

PLAIN LANGUAGE SUMMARY

Risk, recurrence and survival outcomes after surgery and molecular changes possibly involved in the genesis of aristolochic acid-associated urinary tract cancers Background: The association between aristolochic acid (AA) and primary urothelial carcinoma (UC) has been summarized by a 2013-published meta-analysis. Given that additional evidence has been reported in the past 7 years, an updated meta-analysis is needed. Meanwhile, to complete the whole picture, a systematic review of molecular changes possibly involved in AA-mediated urinary tract carcinogenesis was also performed. Methods: We searched PubMed, Embase and four Chinese databases for human studies up to October 2020. Studies comparing the risk of urinary tract cancer (UTC) between patients with and without AA exposure and studies investigating the molecular changes in AA-associated UTC (AA-UTC) using human tissue samples were eligible for inclusion. Thirty-eight studies were finally included. Results: The results showed that exposure to AA was associated with a 6-fold increased risk of primary UTC (UC and renal cell carcinoma, RCC) and a 1.8-fold increased risk of postoperatively recurrent UC. After studies reporting primary AA-upper tract UC (AA-UTUC) were analyzed, a 1.9-fold increased risk of bladder recurrence and a 3.8-fold increased risk of contralateral UTUC recurrence was observed. Additionally, exposure to AA worsened the postoperative survival of patients with UTUC by a 2-fold increased risk of overall death and a 3-fold increased risk of death from other diseases and recurrences. However, there was no effect on death due to cancer. Lastly, AA seemed to play different roles in the etiology of UTUC and RCC based on the observations of different mutation loads and different distributions of AA-induced mutations in AA-UTUC and AA-RCC samples. Conclusions: Implementing effective strategies to completely protect people from exposure to AA is urgently needed. Moreover, more effort should be made in identifying the precise carcinogenic mechanisms of AA-UTC to determine the future treatment strategies.

An Overview on Analytical Methods for Quantitative Determination of Aristolochic Acids

Background:

Aristolochic acids are chemically linked to nitrophenanthrene carboxylic acids which are found in aristolochia plants. These compounds are intrinsically carcinogenic, while they have been used in traditional medicine from a long time ago. Despite the beneficial effects of herbals for treating some diseases, they possess some side effects.

Methods:

Therefore, the development of a sensitive and selective procedure for the determination of these harmful components in various complicated samples is an important task for health systems and drug authorities. In the past years, ultra-pressure liquid chromatography, high performance liquid chromatography and capillary electrophoresis with different detection systems were used for determination of aristolochic acids in various samples.

Results:

In this review, different analytical methods have been discussed in brief and applications of them in diverse samples have been summarized.

Conclusion:

Different approaches are compared from point of sensitivity, selectivity, and extraction efficiency.

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.

Aristolochic Acids as Persistent Soil Pollutants: Determination of Risk for Human Exposure and Nephropathy from Plant Uptake

Exposure to aristolochic acids (AAs) from Aristolochia plants is one of the major global causes of nephropathy, including Balkan endemic nephropathy (BEN); renal failure; and urothelial cancer. The high incidence of BEN on the Balkan Peninsula is assumed to result from consumption of Aristolochia clematitis L. seeds coharvested with crops. Here, we show that AAs are long-lived soil contaminants that enter wheat and maize plants by root uptake with strong pH dependence. Soil and crops from Serbian farms in areas endemic for A. clematitis were found to be extensively contaminated with AAs, with contamination strongly correlated with local incidence of BEN. The persistence of AAs as soil contaminants suggests that weed control for A. clematitis plants is needed to reduce the incidence of BEN and aristolochic acid nephropathy, systematic surveys of soil and crop AA levels would identify high-risk regions, and it is imperative to research soil-remediation methods.

Medicinally Used Asarum Species: High-Resolution LC-MS Analysis of Aristolochic Acid Analogs and In vitro Toxicity Screening in HK-2 Cells

Species of Asarum are used in traditional Chinese medicine and, similar to members of the genus Aristolochia, they contain aristolochic acid analogs (AAAs). These compounds are known for their nephrotoxic and carcinogenic effects. So far, the phytochemistry and nephrotoxicity of species of Asarum is not well studied. A high-resolution LC-MS-based metabolomic approach was used to study the phytochemical variation in medicinally used Asarum species. The cytotoxicity of the samples was assessed using human kidney (HK-2) cells. The majority of samples contained potentially nephrotoxic AAAs, including 9-methoxy aristolactam (AL) IV, AL I, and AL IV. These compounds were present in methanol as well as water extracts. AAAs were detected in all parts of the plant. The majority of the extracts were not cytotoxic to HK-2 cells at the doses tested. However, other mechanisms relating to aristolochic acid nephropathy and cancer development, such as DNA adduct formation may occur. The results of this study provide a model for assessing lesser-known plant species for toxicity.

Interference-free spectrofluorometric quantification of aristolochic acid I and aristololactam I in five Chinese herbal medicines using chemical derivatization enhancement and second-order calibration methods

A rapid interference-free spectrofluorometric method combined with the excitation-emission matrix fluorescence and the second-order calibration methods based on the alternating penalty trilinear decomposition (APTLD) and the self-weighted alternating trilinear decomposition (SWATLD) algorithms, was proposed for the simultaneous determination of nephrotoxic aristolochic acid I (AA-I) and aristololactam I (AL-I) in five Chinese herbal medicines. The method was based on a chemical derivatization that converts the non-fluorescent AA-I to high-fluorescent AL-I, achieving a high sensitive and simultaneous quantification of the analytes. The variables of the derivatization reaction that conducted by using zinc powder in acetose methanol aqueous solution, were studied and optimized for best quantification results of AA-I and AL-I. The satisfactory results of AA-I and AL-I for the spiked recovery assay were achieved with average recoveries in the range of 100.4-103.8% and RMSEPs <0.78ngmL^-1, which validate the accuracy and reliability of the proposed method. The contents of AA-I and AL-I in five herbal medicines obtained from the proposed method were also in good accordance with those of the validated LC-MS/MS method. In light of high sensitive fluorescence detection, the limits of detection (LODs) of AA-I and AL-I for the proposed method compare favorably with that of the LC-MS/MS method, with the LODs <0.35 and 0.29ngmL^-1, respectively. The proposed strategy based on the APTLD and SWATLD algorithms by virtue of the "second-order advantage", can be considered as an attractive and green alternative for the quantification of AA-I and AL-I in complex herbal medicine matrices without any prior separations and clear-up processes.

New Approaches for Biomonitoring Exposure to the Human Carcinogen Aristolochic Acid

Aristolochic acids (AA) are found in all Aristolochia herbaceous plants, many of which have been used worldwide for medicinal purposes for centuries. AA are causal agents of the chronic kidney disease entity termed aristolochic acid nephropathy (AAN) and potent upper urinary tract carcinogens in humans. AAN and upper urinary tract cancers are endemic in rural areas of Croatia and other Balkan countries where exposure to AA occurs through the ingestion of home-baked bread contaminated with Aristolochia seeds. In Asia, exposure to AA occurs through usage of traditional Chinese medicinal herbs containing Aristolochia. Despite warnings from regulatory agencies, traditional Chinese herbs containing AA continue to be used world-wide. In this review, we highlight novel approaches to quantify exposure to AA, by analysis of aristolactam (AL) DNA adducts, employing ultraperformance liquid chromatography-electrospray ionization/multistage mass spectrometry (UPLC-ESI/MSⁿ). DNA adducts are a measure of internal exposure to AA and serve as an important end point for cross-species extrapolation of toxicity data and human risk assessment. The level of sensitivity of UPLC-ESI/MSⁿ surpasses the limits of detection of AL-DNA adducts obtained by ³²P-postlabeling techniques, the most widely employed methods for detecting putative DNA adducts in humans. AL-DNA adducts can be measured by UPLC-ESI/MS³, not only in fresh frozen renal tissue, but also in formalin-fixed, paraffin-embedded (FFPE) samples, an underutilized biospecimen for assessing chemical exposures, and in exfoliated urinary cells, a non-invasive approach. The frequent detection of AL DNA adducts in renal tissues, combined with the characteristic mutational spectrum induced by AA in TP53 and other genes provides compelling data for a role of AA in upper urothelial tract cancer.

Determination of aristolochic acids by high-performance liquid chromatography with fluorescence detection

Nephrotoxic and carcinogenic aristolochic acids (AAs) are naturally occurring nitrophenanthrene carboxylic acids in the herbal genus Aristolochia. The misuse of AA-containing herbs in preparing slimming drugs has caused hundred of cases of kidney disease in Belgium women in a slimming regime in the early 1990s. Accumulating evidence also suggested that prolong dietary intake of AA-contaminated food is one of the major causes to the Balkan endemic nephropathy that was first observed in the late 1950s. Therefore, analytical methods of high sensitivity are extremely important for safeguarding human exposure to AA-containing herbal medicines, herbal remedies, and food composites. In this paper, we describe the development of a new high-performance liquid chromatography coupled fluorescence detector (HPLC-FLD) method for the sensitive determination of AAs. The method makes use of a novel cysteine-induced denitration reaction that "turns on" the fluorescence of AAs for fluorometric detections. Our results showed that the combination of cysteine-induced denitration and HPLC-FLD analysis allows for sensitive quantification of AA-I and AA-II at detection limits of 27.1 and 25.4 ng/g, respectively. The method was validated and has been successfully applied in quantifying AAs in Chinese herbal medicines.

Risk assessment of upper tract urothelial carcinoma related to aristolochic acid

BACKGROUND

Aristolochic acid is a toxin found in plants of the genus Aristolochia, to which humans can be exposed either through certain Chinese herbal medicines or through inadvertent commingling with food crops. Our objective was to estimate cumulative exposures of aristolochic acid associated with increased risk of end-stage renal disease (ESRD), and to conduct a systematic review and meta-analysis on aristolochic acid-induced upper tract urothelial carcinoma (UUC).

METHODS

Using epidemiologic studies on aristolochic acid-related disease from multiple different regions of the world, a systematic review was conducted in which relative risks (RR), HRs, and ORs were derived or extracted directly, and a meta-analysis was conducted. One study was used to estimate a benchmark dose lower confidence limit (BMDL) for aristolochic acid-related ESRD.

RESULTS

Mean values for risk ratios, ORs, RRs, or HRs, of UUC caused by aristolochic acid ranged from 1 to 49. A meta-analysis of these studies resulted in a pooled OR of 5.97 [95% confidence interval (CI), 2.78-12.84] for this aristolochic acid-related cancer. The obtained BMDL for aristolochic acid-related ESRD was 0.42 g cumulative aristolochic acid exposure.

CONCLUSIONS

Aristolochic acid exposure is significantly associated with an increased risk of UUC, and there is a dose-dependent relationship between cumulative aristolochic acid exposure and ESRD risk.

IMPACT

Individuals who use certain Chinese herbal medicines may significantly increase their risk of developing UUC and/or ESRD, as would individuals who are inadvertently exposed to aristolochic acid through commingling of Aristolochia plants with harvested food crops.

Biomonitoring of aristolactam-DNA adducts in human tissues using ultra-performance liquid chromatography/ion-trap mass spectrometry

Aristolochic acids (AAs) are a structurally related family of nephrotoxic and carcinogenic nitrophenanthrene compounds found in Aristolochia herbaceous plants, many of which have been used worldwide for medicinal purposes. AAs have been implicated in the etiology of so-called Chinese herbs nephropathy and of Balkan endemic nephropathy. Both of these disease syndromes are associated with carcinomas of the upper urinary tract (UUC). 8-Methoxy-6-nitrophenanthro-[3,4-d]-1,3-dioxolo-5-carboxylic acid (AA-I) is a principal component of Aristolochia herbs. Following metabolic activation, AA-I reacts with DNA to form aristolactam (AL-I)-DNA adducts. We have developed a sensitive analytical method, using ultraperformance liquid chromatography-electrospray ionization/multistage mass spectrometry (UPLC-ESI/MS(n)) with a linear quadrupole ion-trap mass spectrometer, to measure 7-(deoxyadenosin-N(6)-yl) aristolactam I (dA-AL-I) and 7-(deoxyguanosin-N(2)-yl) aristolactam I (dG-AL-I) adducts. Using 10 μg of DNA for measurements, the lower limits of quantitation of dA-AL-I and dG-AL-I are, respectively, 0.3 and 1.0 adducts per 10(8) DNA bases. We have used UPLC-ESI/MS(n) to quantify AL-DNA adducts in tissues of rodents exposed to AA and in the renal cortex of patients with UUC who reside in Taiwan, where the incidence of this uncommon cancer is the highest reported for any country in the world. In human tissues, dA-AL-I was detected at levels ranging from 9 to 338 adducts per 10(8) DNA bases, whereas dG-AL-I was not found. We conclude that UPLC-ESI/MS(n) is a highly sensitive, specific and robust analytical method, positioned to supplant (32)P-postlabeling techniques currently used for biomonitoring of DNA adducts in human tissues. Importantly, UPLC-ESI/MS(n) could be used to document exposure to AA, the toxicant responsible for AA nephropathy and its associated UUC.

Comparative study of the contents of analogues of aristolochic acid in two kinds of Aristolochiae Fructus by high-performance liquid chromatography

Aristolochiae Fructus ("Madouling") is derived from the fruits of Aristolochia contorta and A. debilis (Aristolochiaceae). These two species contain potentially nephrotoxic constituents, but are officially used in China. Distinction of constituents and toxicity between these two species remains unclear. A high-performance liquid chromatography method was developed and validated for the simultaneous determination of seven analogues of aristolochic acid (aristolochic acids I, II, IIIa, IVa and VIIa), as well as aristololactams I and II in Aristolochiae Fructus. Chromatographic separation was achieved on a Zorbax SB-C(18) column with a gradient mobile phase comprising acetonitrile and 1 % acetic acid-30 mM triethylamine (20:1, v/v) buffer. Analytes were detected with a diode array detector at 250 and 260 nm. The contents of seven constituents in samples (11 batches of A. contorta fruits, 15 batches of A. debilis fruits and 33 commercial samples of Madouling) were determined. The content of aristolochic acid IVa was higher than that of aristolochic acid VIIa in A. contorta fruits, whereas the opposite was true in A. debilis fruits. This feature can be used to distinguish the two species from each other and identify the resource plant of Madouling. Through a morphological method and a newly found principle based on the ratio AA-IVa/AA-VIIa, we found that the 33 commercial samples collected from 12 provinces in China were all derived from the fruits of A. contorta.

Assessment of Chinese medicinal herb metabolite profiles by UPLC-MS-based methodology for the detection of aristolochic acids

In this study, aristolochic acid in different herbal medicines containing a mixture of varying herb species was identified through fingerprint pattern similarities. Aristolochic acid I and II are nephrotoxic compounds naturally present in the Aristolochia plant species that are commonly used in Chinese herbal medicines. Twenty-four commercially available herbal formulations were extracted into an aqueous solution and injected into a UPLC-MS system. All the samples were analysed by multiple reaction monitoring (MRM) to check for the presence of aristolochic acids I and II. The same samples were then fingerprinted using two different gradient methods and the chromatograms deconvoluted into retention time (RT) and masses for the chemicals present taking concentration into account. Statistical analysis of this data revealed that samples were highly heterogeneous, and that the main differences between the preparations were concentrations of polar compounds. A model was constructed where the samples could be separated into two groups differentiated by the presence of the two forms of aristolochic acid.

Characterization and determination of six aristolochic acids and three aristololactams in medicinal plants and their preparations by high-performance liquid chromatography-photodiode array detection/electrospray ionization mass spectrometry

Aristolochic acid derivatives (AAs) and aristolactam derivatives (ALs) have been characterized by electrospray ionization mass spectrometry, and their fragmentation pathways are proposed. ALs exhibit a single ionization product [M+H]+, whereas AAs show multiple ionization products. By optimizing the chromatographic separation and mass spectrometric parameters, the precursor ions of the derivatives with the best responses were found, and the sensitivities in the determination of the nine derivatives were improved. Based on the investigation of ionization behaviour, a HPLC-DAD/ESI-MS (high-performance liquid chromatography-photodiode array detection/electrospray ionization mass spectrometry) method has been developed for simultaneous analysis of nine derivatives, i.e., AA I, AA II, AA C, AA D, 7-OH AA I, aristolic acid I, AL AII, AL IIIa and AL IVa, in nine medicinal herbs and two preparations. The method appears to be suitable for safety assurance and quality control of commercially available samples with good selectivity and suitable sensitivity.

Determination of glucosinolates in traditional Chinese herbs by high-performance liquid chromatography and electrospray ionization mass spectrometry

A reversed-phase HPLC method has been developed for determination of twelve intact glucosinolates--glucoiberin, glucocheirolin, progoitrin, sinigrin, epiprogoitrin, glucoraphenin, sinalbin, gluconapin, glucosibarin, glucotropaeolin, glucoerucin, and gluconasturtiin--in ten traditional Chinese plants. The samples were extracted with methanol and the extracts were cleaned on an activated Florisil column. A mobile phase gradient prepared from methanol and 30 mmol L(-1) ammonium acetate at pH 5.0 enabled baseline separation of the glucosinolates. Glucosinolate detection was confirmed by quadrupole time-of-flight tandem mass spectrometric analysis in negative-ionization mode. Detection limits ranged from 0.06 to 0.36 microg g(-1) when 5 g of dried plant was analyzed. Recoveries of the glucosinolates were better than 85% and precision (relative standard derivation, n = 3) ranged from 5.3 to 14.6%. Analysis of the glucosinolates provided scientific evidence enabling differentiation of three pairs of easily confused plants.