Biochemistry and toxicology of the diterpenoid glycoside atractyloside

Direct and indirect targets of carboxyatractyloside, including overlooked toxicity toward nucleoside diphosphate kinase (NDPK) and mitochondrial H+ leak

CONTEXT

The toxicity of atractyloside/carboxyatractyloside is generally well recognized and commonly ascribed to the inhibition of mitochondrial ADP/ATP carriers, which are pivotal for oxidative phosphorylation. However, these glycosides may 'paralyze' additional target proteins.

OBJECTIVE

This review presents many facts about atractyloside/carboxyatractyloside and their plant producers, such as Xanthium spp. (Asteraceae), named cockleburs.

METHODS

Published studies and other information were obtained from databases, such as 'CABI - Invasive Species Compendium', 'PubMed', and 'The World Checklist of Vascular Plants', from 1957 to December 2022. The following major keywords were used: 'carboxyatractyloside', 'cockleburs', 'hepatotoxicity', 'mitochondria', 'nephrotoxicity', and 'Xanthium'.

RESULTS

In the third decade of the twenty first century, public awareness of the severe toxicity of cockleburs is still limited. Such toxicity is often only perceived by specialists in Europe and other continents. Interestingly, cocklebur is among the most widely distributed invasive plants worldwide, and the recognition of new European stands of Xanthium spp. is provided here. The findings arising from field and laboratory research conducted by the author revealed that (i) some livestock populations may instinctively avoid eating cocklebur while grazing, (ii) carboxyatractyloside inhibits ADP/GDP metabolism, and (iii) the direct/indirect target proteins of carboxyatractyloside are ambiguous.

CONCLUSIONS

Many aspects of the Xanthium genus still require substantial investigation/revision in the future, such as the unification of the Latin nomenclature of currently distinguished species, bur morphology status, true fruit (achene) description and biogeography of cockleburs, and a detailed description of the physiological roles of atractyloside/carboxyatractyloside and the toxicity of these glycosides, mainly toward mammals. Therefore, a more careful interpretation of atractyloside/carboxyatractyloside data, including laboratory tests using Xanthium-derived extracts and purified toxins, is needed.

Multiorgan failure caused by Chinese herbal medicine Xanthii Fructus poisoning: a case report

BACKGROUND

Xanthii Fructus was used in the treatment of rhinitis and related nasal disease. It is the most commonly used chemically active component in compounds formulated for the treatment of rhinitis. However, poisoning, resulting in serious consequences, can easily occur owing to cocklebur overdose, improper processing, or usage without processing.

CASE PRESENTATION

We reported on a 55-year-old man who experienced allergic rhinitis for 2.5 years. He ingested unprocessed Xanthii Fructus for 2 months as treatment. However, he developed anorexia; nausea; abdominal pain; general weakness; hiccups; oliguria and anuria; significantly elevated serum alanine aminotransferase, aspartate aminotransferase, and creatinine levels; and abnormalities in blood coagulation series. Nutritional support; daily drugs for liver protection, gastric protection, inflammation reduction; fresh plasma; and cryoprecipitate infusion were administered. Continuous venovenous hemodialysis (Prismaflex ST100) was also administered. However, the patient's multiple organ failure gradually worsened, ultimately leading to death.

CONCLUSION

Xanthii Fructus poisoning affects multiple systems, and its clinical manifestations are complex. Therefore, it is easily misdiagnosed and missed. Along with careful inquiry of medical and medication history, early diagnosis and intervention are vital for a successful treatment. It is also important to educate people and create awareness about this poisoning. Therefore, this intractable case has great clinical significance.

A case of carboxyatractyloside intoxication by ingestion of the cocklebur (Xanthium strumarium) in a Korean native cow

A 19-month-old Korean native cow died the following day after consuming new silage. Grossly, the liver showed enlargement, redness, and haemorrhages in all the lobes. Additionally, many of the bur-shaped fruits of the cocklebur (Xanthium strumarium) were found in the gastric contents. The histological evaluation confirmed centrilobular hepatic necrosis. Additionally, carboxyatractyloside (CATR), a material fatal to animals found in the cocklebur, was detected in the gastric contents using high-performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF-MS). Based on the pathological findings and analytical confirmation, CATR intoxication was diagnosed. Therefore, careful feeding and elimination of the cocklebur is essential for minimising economic loss.

Puerarin mitigates oxidative injuries, opening of mitochondrial permeability transition pores and pathological damage associated with liver and kidney in Xanthium strumarium-intoxicated rats

In this study, the therapeutic effects of puerarin on Xanthium strumarium toxicity, which can develop in many species and does not have a specific antidote, were investigated. A single dose of 100 g/kg X. strumarium seeds was administered by gavage to female Sprague-Dawley rats, 6 h following which 200 mg/kg puerarin was administered by the same route, with puerarin administration being repeated daily at the same time. After completing the application, the blood, liver and kidney tissues of the rats were examined. Further, the biochemical parameters, glucose, MDA, GSH, SOD, mitochondrial Ca²⁺ and mitochondrial permeability transition pore (mPTP) opening levels, apoptotic factors (TUNEL, Bax and Bcl-2), ATP synthase and histopathological changes of the experimental rats were examined. The results revealed that while the administration of X. strumarium resulted in increased blood AST, ALT, ALP, LDH, CK, BUN and creatinine levels, it decreased glucose levels. In addition, it increased the MDA levels in the tissues and significantly increased the oxidative stress levels by decreasing the GSH levels and SOD activity. X. strumarium caused an increase in the mitochondrial Ca²⁺ and mPTP opening levels. Moreover, it increased the immunohistochemically determined ATP synthase expression and histopathologically identified necrotic liver cell death rates. Owing to its antioxidant properties and inhibitory effects on mPTP opening, puerarin administered for therapeutic purposes decreased the oxidative damage caused by X. strumarium toxicity, blood biochemical parameter levels, mitochondrial Ca²⁺ levels, mPTP opening, ATP synthase expression and the percentage of necrotic cells. Hence, the reduction in the liver and kidney damage in X. strumarium toxicity by puerarin indicates its potential use as an antidote for X. strumarium poisoning.

Reproductive toxicity of Carlina gummifera L. incense inhalation in adult male wistar rats

Background:

Burning incense of Carlina gummifera L. is a traditional practice in North African countries for religious or ritual intentions.

Aim:

The aim of this study was to investigate the effects of smoke incense of this plant on the reproductive function in adult male rats.

Setting and Design:

This study was conducted in the Integrated Physiology Laboratory.

Materials and Methods:

Plant roots were collected, dried and finely ground in powder form. Adult Wistar rats were randomly assigned to treated groups exposed daily during 60 min for 15 consecutive days to smoke incense at 2, 4 and 6 g and a control group was subjected to the same conditions in the absence of smoke.

Statistical Analysis Used:

Statistical analysis was performed using one-way analysis of variance followed by Tukey's multiple comparison as the post hoc test.

Results:

Exposure to the incense of Carlina gummifera L. seriously affected dose dependently the reproductive function in male rats. It was found that in treated groups, the testicle relative weight decreased, while those of seminal vesicles and prostate increased when compared to the untreated group. Carlina gummifera L. incense inhalation reduced the total number, viability and mobility of epididymis spermatozoa compared to control. Furthermore, incense exposure induced various histological changes in the testes, prostate and seminal vesicles, including in particular a decrease in the number of gametes in the seminiferous tubes, the reduction of prostatic secretions and the macrophagic resorption of the seminal secretions. The effect of Carlina incense on the antioxidant system was evaluated by assaying the two antioxidant enzyme activities catalase and superoxide dismutase as well as thiol group levels in the testicles. Our results showed that fumigation affected these parameters, suggesting that the morphological and functional modifications in the male reproductive system induced by Carlina gummifera L. incense may be related, in part, to the alteration of the oxidative balance in the testicle.

Conclusion:

Smoke incense of Carlina gummifera L. caused marked reproductive toxicity in adult male rats associated with induced oxidative stress.

Coffee Leaves: An Upcoming Novel Food?

Unlike those of coffee beans, the healthy properties of coffee leaves have been overlooked for a long time, even if they are consumed as a beverage by local communities of several African countries. Due to the presence of xanthines, diterpenes, xanthones, and several other polyphenol derivatives as main secondary metabolites, coffee leaves might be useful to prevent many daily disorders. At the same time, as for all bioactive molecules, careless use of coffee leaf infusions may be unsafe due to their adverse effects, such as the excessive stimulant effects on the central nervous system or their interactions with other concomitantly administered drugs. Moreover, the presence of some toxic diterpene derivatives requires careful analytical controls on manufactured products made with coffee leaves. Accordingly, knowledge about the properties of coffee leaves needs to be increased to know if they might be considered a good source for producing new supplements. The purpose of the present review is to highlight the biosynthesis, metabolism, and distribution of the 4 main classes of secondary metabolites present in coffee leaves, their main pharmacological and toxicological aspects, and their main roles in planta. Differences in coffee leaf chemical composition depending on the coffee species will also be carefully considered.

The Detection of Toxic Compounds in Extracts of Callilepis laureola (Oxeye Daisy) and Senecio latifolius (Ragwort) by Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS)

Methods used for the detection of toxic components of Callilepis laureola and Senecio latifolius have ranged from the use of thin-layer chromatography, spectrophotometry, and immunoassay to gas chromatography with mass spectrometry. However, each of these techniques has a number of drawbacks. In this chapter, we will describe a solid-phase extraction technique, which allows for the detection and quantitation of the toxins atractyloside and retrorsine in each plant extract using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). This methodology offers high specificity and sensitivity and the ability to identify a broad range of analytes.

Ethnoveterinary for food-producing animals and related food safety issues: A comprehensive overview about terpenes

Alternatives to the use of conventional veterinary drugs in food-producing animals have gained attention, such as the use of natural products (NPs), mainly to soften the risks to the animal, the environment, and consumer's health. Although NPs have consistent advantages over conventional drugs, they cannot be considered risk free under food safety matters. In this way, this document presents a comprehensive overview of the importance of considering both the pharmacological and toxicological properties of the constituents of a NP from plants intending the standardization and regulation of its use in food-producing animals. Terpenes are the most diverse class of natural substances present in NP of vegetal origin with a broad range of biological activities that can be explored in veterinary science; however, certain plants and terpenes also have significant toxic effects, a fact that can harm the health of animals and consequently generate economic losses and risks for humans. In this context, this review gathered scientific data of vegetal species of importance to ethnoveterinary for food-producing animals, which produce terpenes, its biological effects, and their implications on food safety issues for consumers. For this, more than 300 documents were selected from different online scientific databases. The present data and discussion may contribute to the rational commercial exploration of this class of NPs in veterinary medicine.

Atractyloside targets cancer-associated fibroblasts and inhibits the metastasis of colon cancer

Background

Several evidences have proved that cancer-associated fibroblasts (CAFs) play a crucial role in tumor progression. In fact, CAFs form a major component of tumor microenvironment (TME). Therefore, the development and metastasis of tumors can be effectively inhibited by small molecular compounds that target CAFs.

Methods

In this study, we mainly analyzed the expression profile of colon cancer (CC). We determined the intensity of CAFs in CC tissues by using the immune cell infiltration score. Gene enrichment analysis and the screening of differentially expressed genes were performed on the basis of the intensity of CAFs in CC tissues. We screened the small molecular compounds that were converted from differentially expressed genes. The results indicated that atractyloside was a small molecular compound related to CAFs in CC tissues. We identified the relationship between atractylosides and CAFs through target protein analysis and network analysis, and verified the inhibition effect of atractylosides on CC cells (CCC) by migration assay and scratch wound-healing assays.

Results

We found that many target proteins of atractyloside, such as the matrix metalloproteinase family and integrin proteins, were related to the biological function of CAFs. By performing network analysis, we found that the target proteins FGF1, ITGB1, and EDNRA were closely related to tumor angiogenesis, while the target proteins MMP9 and ITGAV were correlated to an extracellular matrix (ECM) and cell motility. These findings which further confirmed the relationship between atractylosides and CAFs. In addition, transwell cell migration and scratch wound-healing assays proved that atractylosides could significantly inhibit the migration of CCCs.

Conclusions

The atractyloside might be a small molecular compound that potentially targets CAFs and inhibits the development as well as metastasis of CC by changing the TME.

Potential Hepatotoxins Found in Herbal Medicinal Products: A Systematic Review

The risk of liver injury associated with the use of herbal medicinal products (HMPs) is well known among physicians caring for patients under a HMP therapy, as documented in case reports or case series and evidenced by using the Roussel Uclaf Causality Assessment Method (RUCAM) to verify a causal relationship. In many cases, however, the quality of HMPs has rarely been considered regarding potential culprits such as contaminants and toxins possibly incriminated as causes for the liver injury. This review aims to comprehensively assemble details of tentative hepatotoxic contaminants and toxins found in HMPs. Based on the origin, harmful agents may be divided according two main sources, namely the phyto-hepatotoxin and the nonphyto-hepatotoxin groups. More specifically, phyto-hepatotoxins are phytochemicals or their metabolites naturally produced by plants or internally in response to plant stress conditions. In contrast, nonphyto-hepatotoxic elements may include contaminants or adulterants occurring during collection, processing and production, are the result of accumulation of toxic heavy metals by the plant itself due to soil pollutions, or represent mycotoxins, herbicidal and pesticidal residues. The phyto-hepatotoxins detected in HMPs are classified into eight major groups consisting of volatile compounds, phytotoxic proteins, glycosides, terpenoid lactones, terpenoids, alkaloids, anthraquinones, and phenolic acids. Nonphyto-hepatotoxins including metals, mycotoxins, and pesticidal and herbicidal residues and tentative mechanisms of toxicity are discussed. In conclusion, although a variety of potential toxic substances may enter the human body through HMP use, the ability of these toxins to trigger human liver injury remains largely unclear.

Phytochemical investigation, in vitro and in vivo antioxidant properties of aqueous and organic extracts of toxic plant: Atractylis gummifera L

ETHNOPHARMACOLOGICAL RELEVANCE

Atractylis gummifera is a toxic plant widely used in Mediterranean traditional medicine against colds, dizziness, and headaches, as an antisyphilitic, against boils, as a purgative, emetic and deworming. All studies reported on this plant have been carried out either on the plant and its traditional uses, or on cases of poisoning by this plant. However, few pharmacological studies have readjusted the traditional uses of this plant.

AIM OF THE STUDY

The purpose of this article is to carry out a preliminary phytochemical study of Atractylis gummifera and to evaluate in vitro and in vivo antioxidant activity of its aqueous and organic extracts and to provide a complementary analysis of the mechanisms of action of the different antioxidant activity tests studied.

METHODS

The phytochemical study consisted of the hot and cold preparation of aqueous extracts: (decocted, infused, macerated), organic extracts: (methanolic, methanolic macerated, chloroformic, ethyl acetate, petroleum ether) and the determination of the secondary metabolites of these extracts. In addition, the biological study consisted of evaluating antioxidant activity in vitro by five different methods (H₂O₂ radical reduction, DPPH, ABTS, FRAP and RP) and in vivo by SOD and MDA assays.

RESULTS

The methanolic macerated is the richest in total polyphenols (102 ± 1.38 mg EAG/gE), tannins (144.09 ± 3.96 mg EC/gE) and flavonoids (17.25 ± 0.06 mg ER/gE). The same extract has the highest percentage to inhibit hydrogen peroxide (19.24 ± 1.10%) and the most potent reducing power of the ABTS radical (122.6 ± 0.63 mg ET/gE). We also noted that aqueous macerated has the most potent anti-radical activity of DPPH with an IC50 of 2.78 ± 1.03 μg/mL, the strongest reducing power of iron 96.15 ± 1.12 mg EAA/gE and which was confirmed by the FRAP test (102.5 ± 1.66 mg ET/gE). These results are in agreement with the in vivo study which showed an increase in SOD secretion in diabetic mice treated with aqueous macerated extract (904.26 ± 29.10 units/g liver and 714.16 ± 24.83 units/g kidney) and methanol macerated extract (813.61 ± 24.03 units/g liver and 719.46 ± 42.10 units/g kidney) with a statistically insignificant difference between these two extracts. Furthermore, we observed a return to normal MDA levels in mice treated with aqueous macerated extract (128.61 ± 15.76 nM/g liver and 103.18 ± 12.67 nM/g kidney) and methanol macerated extract (130.73 ± 10.73 nM/g liver and 34.28 ± 5.73 nM/g kidney).

CONCLUSION

The aqueous and organic extracts more particularly those prepared by aqueous and methanolic macerations are rich in polyphenols, flavonoids and tannins, and they represent a rich source of natural antioxidants, also they prevent lipid peroxidation and stimulate the secretion of the enzymatic antioxidant SOD.

Simultaneous quantification of atractyloside and carboxyatractyloside in rat plasma by LC-MS/MS: Application to a pharmacokinetic study after oral administration of Xanthii Fructus extract

Xanthii Fructus is extensively used as an herbal medicine. Ingestion of this herb is associated with severe hepatotoxicity and nephrotoxicity. Atractyloside and carboxyatractyloside are two dominative toxic constituents in Xanthii Fructus. However, their pharmacokinetic study is lacking. In this study, a novel high-performance liquid chromatography-tandem mass spectrometry method was developed to simultaneously quantify the rat plasma concentrations of atractyloside and carboxyatractyloside. After protein precipitation, the analytes were chromatographic separated on a ZORBAX Eclipse Plus column (2.1 × 150 mm id, 5 µm) under gradient elute. In the negative electrospray ionization mode, the transitions at m/z 725.3→645.4 for atractyloside, m/z 769.3→689.4 for carboxyatractyloside, and m/z 479.2→121.1 for paeoniflorin (the internal standard) were acquired by multiple reaction monitoring. This analytical method showed good linearity over 1-500 ng/mL for atractyloside and 2-500 ng/mL for carboxyatractyloside with acceptable precision and accuracy. No matrix effect, instability and carryover occurred in the analysis procedure. The extraction recoveries were greater than 85.0%. This method was applied to a preliminary pharmacokinetic study by orally administering Xanthii Fructus extract (9 g/kg) to rats, which was useful to evaluate the role of these two compounds in Xanthii Fructus-induced toxicity.

Ectopic adenine nucleotide translocase activity controls extracellular ADP levels and regulates the F1-ATPase-mediated HDL endocytosis pathway on hepatocytes

Ecto-F₁-ATPase is a complex related to mitochondrial ATP synthase which has been identified as a plasma membrane receptor for apolipoprotein A-I (apoA-I), the major protein of high-density lipoprotein (HDL), and has been shown to contribute to HDL endocytosis in several cell types. On hepatocytes, apoA-I binding to ecto-F₁-ATPase stimulates extracellular ATP hydrolysis into ADP, which subsequently activates a P2Y₁₃-mediated HDL endocytosis pathway. Interestingly, other mitochondrial proteins have been found to be expressed at the plasma membrane of several cell types. Among these, adenine nucleotide translocase (ANT) is an ADP/ATP carrier but its role in controlling extracellular ADP levels and F₁-ATPase-mediated HDL endocytosis has never been investigated. Here we confirmed the presence of ANT at the plasma membrane of human hepatocytes. We then showed that ecto-ANT activity increases or reduces extracellular ADP level, depending on the extracellular ADP/ATP ratio. Interestingly, ecto-ANT co-localized with ecto-F₁-ATPase at the hepatocyte plasma membrane and pharmacological inhibition of ecto-ANT activity increased extracellular ADP level when ecto-F₁-ATPase was activated by apoA-I. This increase in the bioavailability of extracellular ADP accordingly translated into an increase of HDL endocytosis on human hepatocytes. This study thus uncovered a new location and function of ANT for which activity at the cell surface of hepatocytes modulates the concentration of extracellular ADP and regulates HDL endocytosis.

Effects of Oridonin on growth performance and oxidative stress in broilers challenged with lipopolysaccharide

This study was conducted to investigate the effects of oridonin (ORI) on growth performance and antioxidant capacity in broiler chickens that were repeatedly challenged with lipopolysaccharide (LPS). A total of 384 one-day-old male Arbor Acre broiler chickens were randomly assigned to 8 treatments with 6 replicate cages per treatment and 8 birds per replicate. There were 4 dietary treatments: the control group (birds fed the basal diet), the ORI 50 group, the ORI 80 group, and the ORI 100 group (the basal diet supplemented with 50, 80, and 100 mg/kg oridonin, respectively). Broilers were intraperitoneally injected with either 250 μg/kg BW LPS or an equivalent amount of sterile saline at 16, 18, and 20 d of age. LPS decreased the average daily weight gain (ADG), the average daily feed intake (ADFI), and the feed conversion ratio (FCR) of broiler chickens (P < 0.05); oridonin supplementation had no effects on performance whether before or after LPS injection (P > 0.05). LPS stimulation increased the relative weight of the spleen and bursa (P < 0.05); oridonin inclusion markedly attenuated the increased spleen index (P < 0.05). Additionally, the LPS-induced increases in the concentrations of malondialdehyde (MDA) and decreases in activities of total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT) were dramatically attenuated by oridonin in both the serum and liver (P < 0.05). Furthermore, LPS down-regulated the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx1), and CAT in the liver (P < 0.05), However, oridonin inclusion increased the liver mRNA expression levels of Nrf2, Cu/Zn-SOD, Mn-SOD, CAT, and GPx1 (P < 0.05). It was concluded that the dietary oridonin supplementation at an optimum dose of 100 mg/kg improves the antioxidant capacity in broilers, as evidenced by the decrease in MDA and the increase in total SOD activities and mRNA expression levels of the liver antioxidant genes, although the effects on growth performance was negligible.

Comparison of the toxicities, activities and chemical profiles of raw and processed Xanthii Fructus

BACKGROUND

Although toxic, the Chinese medicinal herb Xanthii Fructus (XF) is commonly used to treat traditional Chinese medicine (TCM) symptoms that resemble cold, sinusitis and arthritis. According to TCM theory, stir-baking (a processing method) can reduce the toxicity and enhance the efficacy of XF.

METHODS

Cytotoxicities of raw XF and processed XF (stir-baked XF, SBXF) were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in normal liver derived MIHA cells. Nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) mRNA expression were measured by the Griess reagent and quantitative real-time PCR, respectively. The chemical profiles of XF and SBXF were compared using an established ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method.

RESULTS

SBXF was less toxic than XF in MIHA cells. Both XF and SBXF had anti-inflammatory effects as demonstrated by their abilities to reduce nitric oxide production as well as inducible nitric oxide synthase mRNA expression in lipopolysaccharide-stimulated RAW 264.7 macrophages. Interestingly, the anti-inflammatory effects of SBXF were more potent than that of XF. By comparing the chemical profiles, we found that seven peaks were lower, while nine other peaks were higher in SBXF than in XF. Eleven compounds including carboxyatractyloside, atractyloside and chlorogenic acid corresponding to eleven individual changed peaks were tentatively identified by matching with empirical molecular formulae and mass fragments, as well as literature data.

CONCLUSION

Our study showed that stir-baking significantly reduced the cytotoxicity and enhanced the anti-inflammatory effects of XF; moreover, with a developed ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry method we differentiated XF and SBXF by their chemical profiles. Further studies are warranted to establish the relationship between the alteration of chemical profiles and the changes of medicinal properties caused by stir-baking.

Identification of new highly selective inhibitors of the human ADP/ATP carriers by molecular docking and in vitro transport assays

Mitochondrial carriers are proteins that shuttle a variety of metabolites, nucleotides and coenzymes across the inner mitochondrial membrane. The mitochondrial ADP/ATP carriers (AACs) specifically translocate the ATP synthesized within mitochondria to the cytosol in exchange for the cytosolic ADP, playing a key role in energy production, in promoting cell viability and regulating mitochondrial permeability transition pore opening. In Homo sapiens four genes code for AACs with different tissue distribution and expression patterns. Since AACs are dysregulated in several cancer types, the employment of known and new AAC inhibitors might be crucial for inducing mitochondrial-mediated apoptosis in cancer cells. Albeit carboxyatractyloside (CATR) and bongkrekic acid (BKA) are known to be powerful and highly selective AAC inhibitors, able to induce mitochondrial dysfunction at molecular level and poisoning at physiological level, we estimated here for the first time their affinity for the human recombinant AAC2 by in vitro transport assays. We found that the inhibition constants of CATR and BKA are 4 nM and 2.0 μM, respectively. For finding new AAC inhibitors we also performed a docking-based virtual screening of an in-house developed chemical library and we identified about 100 ligands showing high affinity for the AAC2 binding region. By testing 13 commercially available molecules, out of the 100 predicted candidates, we found that 2 of them, namely suramin and chebulinic acid, are competitive AAC2 inhibitors with inhibition constants 0.3 μM and 2.1 μM, respectively. We also demonstrated that chebulinic acid and suramin are "highly selective" AAC2 inhibitors, since they poorly inhibit other human mitochondrial carriers (namely ORC1, APC1 and AGC1).

Chinese Herbal Medicine-induced Liver Injury

The widespread use of Chinese herbal medicine (CHM) and the associated adverse reactions has attracted the attention of researchers and physicians. Reports have shown that several types of CHM can cause liver injury, with increasing numbers of cases reported every year. The difficulty in characterizing CHM-induced liver injury stems from clinical manifestations, diagnosis and pathogenesis. The clinical manifestations are varied, but gastrointestinal symptoms are the majority. The Council for International Organizations of Medical Sciences scale is currently the most commonly used method for assessing causality in cases of medicine-induced liver injury with excellent sensitivity, specificity and predictive validity. However, the pathogenesis of CHM-induced liver injury is not well understood. The classic view encompasses a contribution from "toxic metabolites" that either elicit an immune response or directly affect cellular biochemical processes or functions. In addition, poor quality and inappropriate clinical use of CHMs contribute to safety concerns. To ensure the safe use of CHMs and decrease the number of hepatotoxic cases, clinicians, researchers and pharmaceutical companies should share responsibility by regulating clinical use, strengthening basic toxicology research and establishing a strict quality control system.

A validated method for quantifying atractyloside and carboxyatractyloside in blood by HPLC-HRMS/MS, a non-fatal case of intoxication with Atractylis gummifera L

Atractyloside (ATR) and carboxyatractyloside (CATR) are diterpene glycosides that are responsible for the toxicity of several Asteraceae plants around the world. Mediterranean gum thistle (Atractylis gummifera L.) and Zulu impila (Callilepis laureola DC.), in particular, are notoriously poisonous and the cause of many accidental deaths, some suicides and even some murders. There is no current method for measuring the two toxins in biological samples that meet the criteria of specificity required in forensic medicine. We have endeavored to fill this analytical gap. Analysis was carried out using a solid-phase extraction and a high-performance liquid chromatography coupled with high-resolution tandem mass spectrometry detection. The method was validated in the whole blood with quantification limits of 0.17 and 0.15 µg/L for ATR and CATR, respectively. The method was applied to a non-fatal case of intoxication with A. gummifera. To the best of the authors' knowledge, this is the first time that a concentration of ATR and CATR in blood (883.1 and 119.0 µg/L, respectively) and urine (230.4 and 140.3 µg/L, respectively) is reported. ATR and CATR were quantified in A. gummifera roots by the standard method addition (3.7 and 5.4 mg/g, respectively).

New biomarkers of coffee consumption identified by the non-targeted metabolomic profiling of cohort study subjects

Coffee contains various bioactives implicated with human health and disease risk. To accurately assess the effects of overall consumption upon health and disease, individual intake must be measured in large epidemiological studies. Metabolomics has emerged as a powerful approach to discover biomarkers of intake for a large range of foods. Here we report the profiling of the urinary metabolome of cohort study subjects to search for new biomarkers of coffee intake. Using repeated 24-hour dietary records and a food frequency questionnaire, 20 high coffee consumers (183–540 mL/d) and 19 low consumers were selected from the French SU.VI.MAX2 cohort. Morning spot urine samples from each subject were profiled by high-resolution mass spectrometry. Partial least-square discriminant analysis of multidimensional liquid chromatography-mass spectrometry data clearly distinguished high consumers from low via 132 significant (p-value<0.05) discriminating features. Ion clusters whose intensities were most elevated in the high consumers were annotated using online and in-house databases and their identities checked using commercial standards and MS-MS fragmentation. The best discriminants, and thus potential markers of coffee consumption, were the glucuronide of the diterpenoid atractyligenin, the diketopiperazine cyclo(isoleucyl-prolyl), and the alkaloid trigonelline. Some caffeine metabolites, such as 1-methylxanthine, were also among the discriminants, however caffeine may be consumed from other sources and its metabolism is subject to inter-individual variation. Receiver operating characteristics curve analysis showed that the biomarkers identified could be used effectively in combination for increased sensitivity and specificity. Once validated in other cohorts or intervention studies, these specific single or combined biomarkers will become a valuable alternative to assessment of coffee intake by dietary survey and finally lead to a better understanding of the health implications of coffee consumption.

Toxicology of some important medicinal plants in southern Africa

Africa is home to two major floral kingdoms: the Paleotropical kingdom of central Africa and the Capensis kingdom of the Western Cape province of South Africa, the latter of which consists of approximately 10,000 species, representing about 20% of Africa's floral 'gold mine', better known as the Cape herbal medicine. Needless to say, such rich flora comes with numerous plants with a potential to cause poisoning to humans. This review document reports important toxic medicinal plants and their toxic ingredients for plant species resident in the southern African region. These include important medicinal uses and pharmacological properties ranging from antimicrobial, antiviral, anticancer, anti-inflammatory as well as those that are used as aphrodisiacs and for maternal health care.

2-O-β-D-Glucopyranosyl-carboxyatractyligenin from Coffea L. inhibits adenine nucleotide translocase in isolated mitochondria but is quantitatively degraded during coffee roasting

Atractyloside (1) and carboxyatractyloside (2) are well-known inhibitors of the adenine nucleotide translocase (ANT) in mitochondria, thus effectively blocking oxidative phosphorylation. Structurally related derivatives atractyligenin (3), 2-O-β-D-glucopyranosyl-atractyligenin (4), 3'-O-β-D-glucopyranosyl-2'-O-isovaleryl-2β-(2-desoxy-atractyligenin)-β-D-glucopyranoside (5), and 2-O-β-D-glucopyranosyl-carboxyatractyligenin (6) were isolated from raw beans of Coffea L. and the impact of 1-6 on ANT activity was evaluated in isolated mitochondria. Among the coffee components, 6 significantly inhibited ANT activity leading to reduced respiration. Quantitative analysis in commercial coffees, experimental roastings of coffee, and model experiments using purified compound 6 consistently revealed a complete degradation during thermal treatment. In comparison, raw coffee extracts were found to contain high levels of 6, which are therefore expected to be present in food products enriched with raw coffee extracts. This implies the necessity of analytically controlling the levels of 6 in raw coffee extracts when used as additives for food products.

Carboxyatractyloside poisoning in humans

OBJECTIVE

Cocklebur (Xanthium strumarium) is an herbaceous annual plant with worldwide distribution. The seeds contain the glycoside carboxyatractyloside, which is highly toxic to animals. We describe nine cases of carboxyatractyloside poisoning in humans which, to our knowledge, has not previously been reported. The clinical, laboratory and histopathological findings and our therapeutic approach are also discussed.

SUBJECTS AND METHODS

The patients presented with acute onset abdominal pain, nausea and vomiting, drowsiness, palpitations, sweating and dyspnoea. Three of them developed convulsions followed by loss of consciousness and death.

RESULTS

Laboratory findings showed raised liver enzymes, indicating severe hepatocellular damage. BUN and creatinine levels were raised, especially in the fatal cases who also displayed findings of consumption coagulopathy. CPK-MB values indicative of myocardial injury were also raised, especially in the fatal cases. Three of the patients died within 48 hours of ingesting carboxyatractyloside. Post-mortem histopathology of the liver confirmed centrilobular hepatic necrosis and renal proximal tubular necrosis, secondary changes owing to increased permeability and microvascular haemorrhage in the cerebrum and cerebellum, and leucocytic infiltrates in the muscles and various organs including pancreas, lungs and myocardium.

CONCLUSIONS

Carboxyatractyloside poisoning causes multiple organ dysfunction and can be fatal. Coagulation abnormalities, hyponatraemia, marked hypoglycaemia, icterus and hepatic and renal failure are signs of a poor prognosis. No antidote is available and supportive therapy is the mainstay of treatment.

The degradation mechanism of toxic atractyloside in herbal medicines by decoction

Atractyloside (ATR) is found in many Asteraceae plants that are commonly used as medicinal herbs in China and other eastern Asian countries. ATR binds specifically to the adenine nucleotide translocator in the inner mitochondrial membrane and competitively inhibits ADP and ATP transport. The toxicity of ATR in medical herbs can be reduced by hydrothermal processing, but the mechanisms of ATR degradation are not well understood. In this study, GC-MS coupled with SPE and TMS derivatisation was used to detect ATR levels in traditional Chinese medicinal herbs. Our results suggest that ATR molecules were disrupted by decomposition, hydrolysis and saponification after heating with water (decoction) for a long period of time. Hydrothermal processing could decompose the endogenous toxic compounds and also facilitate the detoxification of raw materials used in the Chinese medicine industry.

Mortality of a captive axis deer (Axis axis) and a llama (Lama glama) due to ingestion of Wedelia glauca

The current study describes a naturally occurring cluster of cases of Wedelia glauca intoxication. Seven of 14 axis deer (Axis axis) and 1 of 8 llamas (Lama glama) in a zoo of Buenos Aires province, Argentina, died suddenly after ingestion of a new batch of alfalfa (Medicago sativa) hay bales contaminated with the hepatotoxic plant W. glauca. Necropsies of 1 deer and 1 llama were performed. Pathological findings in both animals included severe diffuse acute centrilobular hepatocellular necrosis and hemorrhage, and clear yellowish translucent gelatinous edema on the wall of the gall bladder and the serosa of the choledochoduodenal junction. Fragments of W. glauca plants were identified in the hay based on the botanical characteristics of the leaves. Samples of gastric contents were examined by microhistological analysis, which identified epidermal fragments of W. glauca based on the presence of characteristic uniseriate glandular hairs (trichomes), confirming recent ingestion of W. glauca in both cases. The fragments were quantified and represented 5% of all examined vegetal fragments in the deer and 10% in the llama.

In vivo and in vitro genotoxicity studies of aqueous extract of Xanthium spinosum

The use of plants as a source of palliative or cure for pathological conditions is quite common worldwide. Xanthium spinosum (Asteraceae), popularly known in Brazil as 'espinho de carneiro', is an annual weed from South America, which has been used by empiric medicine to treat neoplasias. Owing to the extensive use of the above-mentioned plant and to the lack of reports about the real effects of its infusion, current study evaluated the genotoxic potential of its aqueous extract at concentrations 0.02 g L-1, 0.1 g L-1 and 0.2 g L-1 by fish micronucleus test and by comet human leukocytes assay. The micronucleus test featured at least 50 cells with micronuclei to every 2,000 cells scored, as a mutagenic parameter. The comet assay was used as a parameter for assessing the level of cell damage and the damage index. Since no significant changes in strain cells exposed to the aqueous extract in the comet and micronucleus assays were reported, it seems that no genotoxicity evidence is extant at the concentrations and in the assays performed.

[Study of four cases of poisoning by Atractylis gummifera L. in Morocco]

Atractylis gummifera L., a poisonous thistle responsible for frequent and sometimes mortal poisonings is known in Mediterranean region and in occident as this plant is used in alternative medicine. The clinical and biological data of four cases of poisoning in Morocco by Atractylis gummifera L. reported and discussed in this study will have to help to review this poisoning in order to inform better and to take care of the poisoned persons. Also this study may contribute to prevent the use of this plant in traditional medicine.

The study on the chromatographic fingerprint of Fructus xanthii by microwave assisted extraction coupled with GC–MS

The chromatographic fingerprint of Fructus xanthii, a kind of Traditional Chinese Medicines (TCMs), was studied by microwave assisted extraction (MAE) coupled with gas chromatography-mass spectrometry (GC-MS). The optimized conditions of MAE were examined. The method of MAE was evaluated in contrast to heat reflux extraction (HRE) method and by the validation tests of precision and repeatability. The relative standard deviations (RSDs) of retention time and peak area of each component were less than 0.2% and 6%, respectively. Twenty-five different batches of samples collected from different producing areas and the toasting process of F. xanthii were studied. The characteristic differences in the producing areas and the chemical variances in the toasting process were obtained and studied by principal components analysis (PCA) and similarity analysis. The trends of main varying components were attempted to be described in order to specify the related pharmacology and toxicology in crude and toasted samples. The results suggest that the chromatographic fingerprint developed by MAE coupled with GC-MS provides useful information to reveal the quality of F. xanthii and evaluate the quality changes in the producing process.

Intoxication par le chardon à glu chez une femme enceinte

BACKGROUND

Atractylis gummifera is poisonous and its ingestion causes illness, characterized principally by hepatorenal injury, often fatal. The toxicity of this plant to the fetus is not known. We report a case of poisoning during pregnancy.

CASE REPORT

A 28 year-old woman was admitted to our intensive care unit for Atractylis gummifera poisoning during her 24th week of pregnancy. She showed gastrointestinal symptoms, impaired consciousness, hypoglycemia, hepatic cytolysis and decreased factor V blood levels. The mother recovered after symptomatic treatment. A healthy boy was delivered vaginally at 39 weeks and his clinical findings and laboratory results were normal at birth and a week later.

DISCUSSION

Poisoning by Atractylis gummifera has not previously been reported during pregnancy. The favorable course of our patient and her infant do not rule out possible fetal damage from which he recovered, as his mother did.

The effects of oridonin on cell growth, cell cycle, cell migration and differentiation in melanoma cells

Oridonin, a diterpenoid isolated from Rabdosia rubescens (Hemsl.) Hara, is currently one of the most important traditional Chinese herbal medicines. We investigated the anti-proliferation effect of oridonin on the cultured murine melanoma cell line K1735M2. The growth inhibition activity of oridonin for K1735M2 cells occurred in a time- and dose-dependent manner (IC50 was 7.4+/-0.6 microM). Further studies showed that these inhibition effects were associated with dose-dependent G2/M phase arrest and differentiation induction. Detection of morphological observation showed that oridonin could induce K1735M2 cells to produce dendrite-like structures. The results of the migration indicated that oridonin affected motility of K1735M2 cells in a dose-dependent manner. These results suggested that oridonin is a potential candidate for melanoma cancer therapy.

Identification of atractyloside by LC-ESI-MS in alleged herbal poisonings

An LC-MS screening method was developed to detect the presence of atractyloside (ATR), the toxic principle of a commonly used medicinal plant in South Africa, Callilepis laureola, in biological matrices such as body fluids and human viscera.

Nephrotoxicity associated with exposure to plant toxins, with particular reference to Africa

Acute renal failure is a frequent cause of morbidity and mortality in the hospitalized population worldwide. In Africa, apart from hemodynamic causes and infections, herbal remedies contribute to both morbidity and mortality, although these causes often go unrecognized. This paper reviews reports of herbal remedies that have been shown to result in nephrotoxicity. The indications for use of the remedies, signs and symptoms in poisoned patients, and the methods used to detect toxic compounds in plant specimens or in biological fluids are covered.

Atractylis gummifera L. poisoning: an ethnopharmacological review

Atractylis gummifera L. (Asteraceae) is a thistle located in the Mediterranean regions. Despite the plant's well-known toxicity, its ingestion continues to be a common cause of poisoning. The toxicity of Atractylis gummifera resides in atractyloside and carboxyatractyloside, two diterpenoid glucosides capable of inhibiting mitochondrial oxidative phosphorylation. Both constituents interact with a mitochondrial protein, the adenine nucleotide translocator, responsible for the ATP/ADP antiport and involved in mitochondrial membrane permeabilization. Poisoned patients manifest characteristic symptoms such as nausea, vomiting, epigastric and abdominal pain, diarrhoea, anxiety, headache and convulsions, often followed by coma. No specific pharmacological treatment for Atractylis gummifera intoxication is yet available and all the current therapeutic approaches are only symptomatic. In vitro experiments showed that some compounds such as verapamil, or dithiothreitol could protect against the toxic effects of atractyloside, but only if administered before atractyloside exposure. New therapeutic approaches could come from immunotherapy research: some studies have already tried to produce polyclonal Fab fragments against the toxic components of Atractylis gummifera.

IFN-beta induces caspase-mediated apoptosis by disrupting mitochondria in human advanced stage colon cancer cell lines

Various human colon cancer cell lines tested in vitro differed significantly in susceptibility to growth inhibition of recombinant human interferon-beta (rHuIFN-beta). Two p53-mutant lines, COH and CC-M2, derived from high-grade colon adenocarcinoma, showed signs of apoptosis after treatment with 250 IU/ml of HuIFN- beta in the culture medium. The similarly p53-mutated HT-29 line from a grade I adenocarcinoma showed no apoptosis, however, and only cell cycle G1/G0 or S phase retardation with 1000 IU/ml HuIFN-beta. After HuIFN-beta exposure, COH and CC-M2 cells showed increased levels of Fas and FasL proteins, alteration of mitochondrial membrane potential, and activation of caspase-9, caspase-8, and caspase-3 in a time-dependent manner. Treatment of COH and CC-M2 cells with anti-FasL antibodies or rFas/Fc fusion protein, however, could not prevent the apoptosis induced by HuIFN-beta. In contrast, cell-permeable specific inhibitors of the three caspases could inhibit the DNA fragmentation and cell death but not the mitochondrial membrane potential changes. Treatment with mitochondria-stabilizing reagents could significantly abrogate the apoptosis and caspase activation induced by HuIFN-beta. These results suggest that in COH and CC-M2 colon cancer cell lines, HuIFN-beta induces apoptosis mainly through mitochondrial membrane alteration and subsequent activation of the caspase cascade pathway, but not by the Fas/FasL interaction or the p53-dependent apoptotic mechanism.

Mechanism of Impila (Callilepis laureola)-induced cytotoxicity in Hep G2 cells

OBJECTIVES

To determine the mechanism(s) of Impila (Callilepis laureola)-induced toxicity in human hepatoblastoma Hep G2 cells in vitro and the possible prevention of this toxicity by N-acetylcysteine (NAC).

DESIGN AND METHODS

Cells were treated with an aqueous extract of Impila (10 mg/mL) for up to 24 h. NAC (5 mM) was administered either concomitantly with Impila or one hour post Impila treatment. Cytotoxicity was quantitated spectrophotometrically by the metabolism of the tetrazolium dye MTT. Total glutathione (GSH) was measured using the Tietze assay.

RESULTS

Impila produced cytotoxicity and depleted GSH in a concentration- and time-dependent manner. A significant depletion in GSH was observed after 15 min (p < 0.0001 vs. control), whereas significant cytotoxicity was only observed after at least 3 h (p < 0.0001 vs. control). Both concomitant and posttreatment with NAC prevented Impila-induced GSH depletion and resulted in a significant decrease in Impila-induced cytotoxicity (p < 0.001 vs. NAC-untreated cells).

CONCLUSION

Our results suggest the mechanism of Impila-induced cytotoxicity in Hep G2 cells in vitro involves depletion of cellular GSH. Preventing GSH depletion by supplementing cells with NAC reduces cytotoxicity.

Effects of the calcium channel blocker verapamil and sulphydryl reducing agent dithiothreitol on atractyloside toxicity in precision-cut rat renal cortical and liver slices

The effects of dithiothreitol (DTT), a sulfhydryl-containing agent and verapamil (VRP), a calcium channel blocker as possible cytoprotectants against the atractyloside-induced toxicity were characterized in rat kidney and liver slices in vitro using multiple markers of toxicity. Precision-cut slices (200 microM thick) were either incubated with atractyloside (2 mM) or initially preincubated with either DTT (5 mM) or VRP (100 microM) for 30 min followed by exposure to atractyloside (2 mM) for 3 h at 37 degrees C on a rocker platform rotated at approximately 3 rpm. All of the toxicity parameters were sensitive to exposure to atractyloside, but treatment with DTT or VRP alone did not provide any indication of damage to the tissues. Preincubation of slices containing either DTT or VRP for 30 min provided total protection against atractyloside-induced increase in LDH leakage in both kidney and liver slices. Increased induction of lipid peroxidation by atractyloside in liver slices was completely abolished by DTT and VRP. Both DTT and VRP provided partial protection against atractyloside-induced inhibition of gluconeogenesis in both kidney and liver slices. Atractyloside-induced ATP depletion in both kidney and liver slices was partially abolished by VRP but not DTT. The significant depletion of GSH in the kidney slices by atractyloside was completely reversed by DTT only, while VRP alone reversed the same process in liver slices. Decreased MTT reductive capacity and significant increase in ALT leakage caused by atractyloside in liver slices was partially reversed. Complete protection was achieved with both DTT and VRP against atractyloside-induced inhibition of PAH uptake in kidney slices. These findings suggest that both DTT and VRP exert cytoprotective effects in atractyloside-induced biochemical perturbation, effects that differ in liver and kidney. The effect of these agents on atractyloside has provided us with a further understanding of the molecular mechanism of its action.

The toxicity of Callilepis laureola, a South African traditional herbal medicine

OBJECTIVES

To review the literature on the toxicity of Callilepis laureola, and to assess the cytotoxicity of C. laureola in human hepatoblastoma Hep G2 cells in vitro.

DESIGN AND METHODS

Cells were incubated for up to 48 h in the presence of increasing concentrations of an aqueous extract of C. laureola (0.3-13.3 mg/mL). Cytotoxicity was quantitated spectrophotometrically by the metabolism of the tetrazolium dye MTT. Cytoviability of the control cells was considered to be 100%.

RESULTS

C. laureola produced cytotoxicity in a concentration-dependent manner. Cytotoxicity was significant at all concentrations tested (0.3-2.5 mg/mL, p < 0.05 vs. controls and 3.3-13.3 mg/mL, p < 0.0001 vs. controls). After 6 h, 100% toxicity was observed at a concentration of 6.7 mg/mL.

CONCLUSION

C. laureola causes significant cytotoxicity in Hep G2 cells in vitro. These findings are in accordance with the observed hepatotoxicity in clinical cases of C. laureola poisoning.

The biochemistry and toxicity of atractyloside: a review

Atractyloside poisoning is an infrequent but often fatal form of herbal poisoning, which occurs worldwide but especially in Africa and the Mediterranean regions. The primary mechanism of atractyloside poisoning is known to be inhibition of the mitochondrial ADP transporter. Poisoning in humans may present with either acute hepatic or renal pathology and it is possible that there is a second, different mechanism of toxicity to the hepatocyte. Atractyloside in large amounts gives rise to massive necrosis, but in vitro studies have shown that at lower doses cells progress to apoptosis. Simple methods for the detection of atractyloside poisoning are at present restricted to thin-layer chromatography in urine and are useful only in the case of severe poisoning. Immunoassays, high-performance liquid chromatography, nuclear magnetic resonance, and a recently developed high-performance liquid chromatography/mass spectrometry method have yet to be applied to clinical diagnoses. There is at present no treatment, but a fuller understanding of the mechanisms of toxicity may lead to the application of a number of compounds that are effective in vitro.

The anti-oxidant ebselen antagonizes the release of the apoptogenic factor cytochrome c induced by Fe2+/citrate in rat liver mitochondria

We studied the effects of ebselen (a seleno-organic anti-oxidant), on the release of the apoptogenic factor, cytochrome c, in two different experimental situations damaging mitochondria: (1) Fe(2+)/citrate, known to induce lipid peroxidation consecutively to an oxidative stress; and (2) atractyloside, a ligand of the adenine nucleotide translocator. The effects of ebselen were compared to those of butylated hydroxytoluene (BHT, an inhibitor of lipid peroxidation), and cyclosporine A (CsA, a classical pore antagonist). Ebselen, like BHT, inhibited Fe(2+)/citrate-induced release of cytochrome c, whereas CsA was inactive. On the contrary, neither ebselen nor BHT inhibited atractyloside-induced release of cytochrome c, whereas CsA was potently active. The antioxidant properties of ebselen may protect mitochondria from the consequences of the release of cytochrome c. Thus, it is suggested that the neuroprotective effect of ebselen previously demonstrated in humans and in animals may be due, at least in part, to a mitochondrial protection.