Influence of Processing on the Content of Toxic Carboxyatractyloside and Atractyloside and the Microbiological Status of Xanthium sibiricum Fruits (Cang'erzi).

The dried ripe fruits of Xanthium sibiricum (Cang'erzi) are used in traditional Chinese medicine for the treatment of nasal congestion, nasal discharge, allergic rhinitis, sinusitis, and wind-cold headaches. Carboxyatractyloside and atractyloside are important constituents of the fruits because these diterpenoid glycosides are responsible for their toxicity. In order to evaluate procedures for reducing the amount of the more toxic carboxyatractyloside, the fruits were dried and heated with different methods. Carboxyatractyloside and atractyloside were analysed by a new reversed-phase high-performance liquid chromatographic method using liquid chromatography-diode array detector-tandem mass spectrometry analysis. The results revealed that temperature and drying methods have a strong influence on the content of carboxyatractyloside and atractyloside. Fruits which were treated at higher temperatures showed a lower content of carboxyatractyloside and an increased content of atractyloside, which is 50 times less toxic. This indicates that the roasting process can reduce toxicity effectively. The microbiological colonisation of Xanthium fruits is also reduced by roasting and by drying above 100 °C. For the safe use of Cang'erzi, the effect of processing should be monitored and analysis of carboxyatractyloside and atractyloside should be obligatory in quality control.

2-O-ß-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-ß-D-glucopyranosyl-atractyligenin (4), 3'-O-ß-D-glucopyranosyl-2'-O-isovaleryl-2ß-(2-desoxy-atractyligenin)-ß-D-glucopyranoside (5), and 2-O-ß-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.

[Determination of carboxyatractyloside and atractyloside in Xanthii Fructus by HPLC].

OBJECTIVE: To determine carboxyatractyloside and atractyloside in Xanthii Fructus by HPLC. METHOD: By HPLC, Agilent ZORBAX SB-phenyl (4.6 mm x 250 mm, 5 microm) column was adopted, with acetonitrile-0.01 mol x L(-1) NaH2PO4 (pH 6) as the mobile phase for gradient elution at the flow rate of 1.0 mL x min(-1). The detection wavelength was 203 nm, and the temperature was set at 35 degrees C. RESULT: Carboxyatractyloside showed a good linearity within the range of 0.0972-1.944 microg and atractyloside showed a good linearity within the range of 0.1030-2.060 microg. The recovery rate of carboxyatractyloside was 100. 3% and that of atractyloside was 102.5%. The RSD were 0.67% and 1.4% (n=6). CONCLUSION: This method is so simple, practical and highly repeatable that is can be used for quality control of Xanthii Fructus.

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.

Diterpene glycosides from Iphiona aucheri.

Iphiona aucheri is responsible for poisoning racing camels (Camelus dromedarius) in the United Arab Emirates U. A. E. Terpenoids, a non-toxic pyrrolizidine alkaloid and two diterpene glycosides, atractyloside and carboxyatractyloside, were isolated and their structures determined by spectroscopic methods. Atractyloside and carboxyatractyloside were identified as the toxic principle of the plant.

The isolation of a storage organelle of atractyloside in Callilepis laureola.

A method has been developed for the preparation of protoplasts from both the leaves and tubers of Callilepis laureola, a plant used extensively as a medicament by black people in South Africa. The cellular vacuoles from these protoplasts were isolated and tested for the presence of the nephrotoxic substance, atractyloside, by thin layer chromatography and immunoassay. Both methods indicate that the vacuole of C. laureola is the primary site of storage for atractyloside in the cells of the tuber.

Toxicity of Callilepis laureola.

Callilepis laureola, which has been found to cause fatal liver necrosis in the Black population of Natal, is widely used as a herbal medicine. Chemical extraction has yielded a product, identified as atractyloside, which is responsible for the nephrotoxic and hypoglycaemic effects of Callilepis laureola. The hepatotoxic principle has not yet been isolated.

The binding of atractylate and carboxy-atractylate to mitochondria.

35S-labelled atractylate and carboxy-atractylate are produced biosynthetically and used for studying the binding of these specific ligands to the ADP, ATP carrier in beef heart mitochondria. The following results are obtained. 1. Inhibition of translocation activity goes parallel to the increase of binding by [35S]atractylate. No additional binding is observed after full inhibition of translocation is reached giving evidence that atractylate binds exclusively to the carrier. 2. The maximum number of binding sites of both atractylates is about 1.6 mumol/g protein in beef heart mitochondria and decreases on treatment of the membrane by Pi, freezing, ageing, etc. The dissociation constants of the binding are approximately for atractylate Kd = 5-10(-8) M and for carboxy-atractylate Kd = 10(-8) M. The mass action plots of the concentration dependence for the binding are nonlinear-convex in particular with carboxy-atractylate and more linear with atractylate. Nonlinearity appears to be caused by some retardation of equilibration in the case of very high affinity binding. 3. The binding of atractylate and carboxy-atractylate is relatively fast in intact mitochondria and slower in aged membranes. There is a slower and a faster binding portion. 4. The atractylates remove ADP in a nearly 1:1 stoichiometry from untreated mitochondria. In aged and Pi-treated membranes the ratio deltaADP/deltaatractylate approaches 0. Obviously binding of carrier sites to ADP is more sensitive to alterations than that of the atractylates. The assumption is maintained that the binding site for atractylate is identical with that for ADP and ATP. 5. Bongkrekate prevents binding of both atractylates. However, when added after, it only removes atractylate but not the carboxy compound because of its different tight binding. The removal of atractylate depends on the synergistic effect of bongkrekate with ADP. 6. The binding studies with [35S]atractylate and in particular the interaction with bongkrekate support the reorienting carrier model in which atractylate as an impermeable ligand fixes the binding site of the carrier outside while with bongkrekate the carrier site is turned to the inside.