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At least 19 recordsLinked to original sources
PubMed2002

Reverse-phase HPLC separation of D-amygdalin and neoamygdalin and optimum conditions for inhibition of racemization of amygdalin.

In boiling aqueous solution, D-amygdalin usually begins to convert into neoamygdalin in 3 min and more than 30% of the initial D-amygdalin is found as neoamygdalin after 30 min. In this report, we establish methods for simple HPLC analysis and the inhibition of D-amygdalin conversion. D-Amygdalin and its conversion product, neoamygdalin, were clearly separated on reverse-phase column chromatography by an optimized eluent of 10 mM sodium phosphate buffer (pH 3.8) containing 6% acetonitrile. Linearity for analyzing D-amygdalin and neoamygdalin was observed in the range from 0.05 to 0.5 mM. The detection limits for D-amygdalin and neoamygdalin were ca. 5 microM per injected amount. We found that D-amygdalin conversion was completely inhibited by adding 0.05% citric acid to the aqueous solution before boiling. To prevent the loss of pharmaceutical potency of Tonin, we applied this method to measure the conversion rate of D-amygdalin. We confirmed that D-amygdalin conversion in Tonin is effectively inhibited by acidic boiling solution with 0.1% citric acid.

Amygdalin↗
PubMed1985

On the metabolism of amygdalin. 2. The distribution of beta-glucosidase activity and orally administered amygdalin in rats.

The organs of 15-day-old rats had the highest capability to hydrolyze amygdalin and prunasin, and most of this activity is concentrated in the tissues of the small and large intestines. The activity decreased with age. In adult rats, the ability of the organs to hydrolyze prunasin is higher than that of amygdalin and is concentrated in the spleen, large intestine, and kidney (35.0, 15.0, and 8.9 micrograms prunasin hydrolyzed . h-1 . g tissue-1). Minced tissues of the liver, spleen, kidney, and stomach contain more hydrolytic capability than the homogenate of these organs, while the reverse is the case with the small and large intestines. When 30 mg amygdalin was orally administered to adult rats, its distribution after the 1st h was as follows: stomach (0.89 mg), small intestine (0.78 mg), spleen (0.36 mg), large intestine (0.30 mg), kidney (0.19 mg), liver (0.10 mg), and serum (5.6 micrograms/mL). At the end of the 2nd h, the highest amygdalin content was found in the large intestine (0.79 mg).

Administration, Oral↗
PubMed1994

Tissue Level Compartmentation of (R)-Amygdalin and Amygdalin Hydrolase Prevents Large-Scale Cyanogenesis in Undamaged Prunus Seeds.

Plum (Prunus domestica) seeds, which contain the cyanogenic diglucoside (R)-amygdalin and lesser amounts of the corresponding monoglucoside (R)-prunasin, release the respiratory toxin HCN upon tissue disruption. Amygdalin hydrolase (AH) and prunasin hydrolase (PH), two specific [beta]-glucosidases responsible for hydrolysis of these glucosides, were purified to near homogeneity by concanavalin A-Sepharose 4B and carboxymethyl-cellulose chromatography. Both proteins appear as polypeptides with molecular masses of 60 kD upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but they exhibit different isoelectric points (PH, 5.6-6.0; AH, 7.8-8.2). AH and PH were localized within mature plum seeds by tissue printing, histochemistry, and silver-enhanced immunogold labeling. As was previously shown in black cherry (Prunus serotina) seeds (E.Swain, C.P. Li, J.E. Poulton [1992] Plant Physiol 100: 291-300), AH and PH are restricted to protein bodies of specific procambial cells and are absent from the cotyledonary parenchyma, bundle sheath, and endosperm cells. In contrast, the cyanogenic glycosides in both plum and black cherry seeds, which were detected by tissue printing, occur solely in the cotyledonary parenchyma and are absent from the procambium and endosperm. It is concluded that tissue level compartmentation prevents large-scale cyanoglycoside hydrolysis in intact Prunus seeds.

Journal Article↗
PubMed2005

[Protective effects of amygdalin on hyperoxia-exposed type II alveolar epithelial cells isolated from premature rat lungs in vitro].

OBJECTIVE: To analyze the effect of hyperoxia on the proliferation and surfactant associated protein messenger RNA levels of type II alveolar epithelial cells (AECIIs) of premature rat, and to investigate the effect of amygdalin on the change resulted from hyperoxia in AECIIs isolated from premature rat lung in vitro. METHODS: The lung tissue of 20-day fetal rat was digested by trypsin and collagenase. AECIIs and lung fibroblasts (LFs) were isolated and purified at different centrifugal force and different adherence, then cultured. The nature of the cultures was identified by cytokeratin staining, vimentin staining and transmission electron micrography. For establishing hyperoxia-exposed cell model, purified AECIIs were cultured for 24 hours after culture flasks were filled with 95% oxygen-5% CO2 at 3 L/min for 10 min, and then sealed. Oxygen concentrations were tested in CYS-1 digital oxygen monitor after 24 hours of exposure. A sample was discarded if its oxygen concentration was < 90%. Cell proliferating vitality was examined by MTT assay after treatment with amygdalin at various concentrations. DNA content, protein expression of proliferating cell nuclear antigen (PCNA) and mRNA levels of SPs of AECIIs were analyzed with flow cytometric assay, Western blot and reverse transcription polymerase chain reaction (RT-PCR) respectively after 24 hours of air or hyperoxia exposure in the presence or absence of 200 micromol/L amygdalin. RESULTS: Excellent yields of highly purified, culturable AECIIs could be obtained from 20-day fetal lungs. The expression of cytokeratin in AECIIs was positive and that of vimentin negative by immunocytochemistry. Those, however, in LFs were just opposite. Lamellar bodies in purified AECIIs were revealed by transmission electron micrography. The established hyperoxia-exposed cell model assured the oxygen concentrations of culture flasks more than 90%. Amygdalin at the concentration range from 50 micromol/L to 200 micromol/L stimulated the proliferation of AECIIs in a dose-dependent manner; however, at the concentration of 400 micromol/L inhibited the proliferation of AECII. Flow cytometric analysis showed that the apoptosis rate and G0/G1 phase percentage increased significantly (P < 0.01), S phase and G2/M phase percentage decreased significantly (P < 0.01), in hyperoxia group compared with that of air group. The apoptosis rate of air plus 200 micromol/L amygdalin group, compared with air group, was not significantly different (P > 0.05); however, G0/G1 phase percentage decreased markedly, S phase percentage increased significantly, G2/M phase percentage did not significantly change (P > 0.05). The apoptosis rate of hyperoxia plus 200 micromol/L amygdalin group was not significantly different (P > 0.05) from that of hyperoxia group, S phase and G2/M phase percentage increased significantly (P < 0.01), G0/G1 phase percentage decreased significantly (P < 0.01). Western blot analysis showed that the protein expression levels of PCNA in all group was significantly different, in turn, hyperoxia group < hyperoxia plus 200 micromol/L amygdalin < air group < air puls 200 micromol/L amygdalin (P < 0.01). SPs mRNA levels were significantly decreased in hyperoxia group, as compared with air group (P < 0.01). After amygdalin was added, SPs mRNA levels were elevated in air plus amygdalin group and hyperoxia plus amygdalin group, as compared with hyperoxia group (P < 0.01, P < 0.05, respectively), but compared with air group, SP mRNA levels were not significantly elevated (P > 0.05). CONCLUSION: AECIIs of premature rats were isolated, purified and cultured successfully. Hyperoxia-exposed cell model was established in AECIIs of premature rat in this experiment. Amygdalin promotes the proliferation of premature rat AECII exposed to air or hyperoxia, the concentration of amygdalin with the best effect was 200 micromol/L. Hyperoxia inhibited the proliferation and decreased SPs mRNAs levels in AECIIs in vitro, which may contribute to hyperoxia-induced lung injury in premature rats. Amygdalin could inhibit the changes of SPs mRNAs levels and cell proliferation of AECIIs resulted from hyperoxia and may play partial protective role in hyperoxia-induced premature lung injury.

Amygdalin↗
PubMed2000

Micellar electrokinetic chromatography for the analysis of D-amygdalin and its epimer in apricot kernel.

We have developed a simple, rapid and reproducible method for the determination of D-amygdalin and its epimer by using micellar electrokinetic chromatography (MEKC). Separation of D-amygdalin was performed in a 20 mM sodium borate buffer (pH 8.5) containing 300 mM sodium dodecyl sulfate using a bare fused-silica capillary. The eluates were monitored by the absorbance at 210 nm. The applied electric field was 278 V/cm, and the time needed for the separation of D-amygdalin did not exceed 6 min. The calibration curve for D-amygdalin showed excellent linearity in the concentration range of 5-500 microg/ml. The migration time and the corrected peak area show relative standard deviations (n=6) of 0.86% and 1.48%, respectively. The limit of detection (S/N=3) for D-amygdalin was 2 microg/ml. Under acidic and neutral conditions, amygdalin exists only as the D-form; however, under basic conditions, it shows both the D- and L-forms with a concentration ratio of 1:1.3 (D-amygdalin/L-amygdalin). Results of HPLC, UV-Vis spectrophotometry, and mass spectrometry reconfirmed the identification of D-amygdalin and its epimer. The number of theoretical plates of D-amygdalin is about 100,000 in MEKC, which is significantly higher than approximately 8,000 of HPLC. This method has been successfully applied to the determination of amygdalin epimers in various apricot kernel extracts and pharmaceutical products.

Amygdalin↗
PubMed1998

In vitro cytotoxicity following specific activation of amygdalin by beta-glucosidase conjugated to a bladder cancer-associated monoclonal antibody.

We describe a novel version of antibody-directed enzyme prodrug therapy (ADEPT), with the use of amygdalin as prodrug. Amygdalin is a naturally occurring cyanogenic glycoside, which can be cleaved by sweet almond beta-glucosidase to yield free cyanide. If amygdalin could be activated specifically at the tumour site, then malignant cells would be killed without the systemic toxicity usually associated with chemotherapy. To this end, we have conjugated beta-glucosidase to a tumour-associated monoclonal antibody (MAb) (HMFG1) and the conjugate has been tested in vitro for specificity and cytotoxicity subsequent to activation of amygdalin. Amygdalin was cytotoxic to HT1376 bladder cancer cells only at high concentrations, whereas the combination of amygdalin with HMFG1-beta-glucosidase enhanced the cytotoxic effect of amygdalin by 36-fold. When 2 concentrations of HMFG1-beta-glucosidase were compared, the toxic effect was dose dependent. The cytotoxicity of amygdalin was also enhanced by the MAb-enzyme conjugate even when the unbound conjugate was removed from the medium prior to exposure to amygdalin and the cells were washed. In addition to the cytotoxic effect, we also demonstrated specificity, using a MAb-enzyme conjugate that does not recognise the HT1376 bladder cancer cells. Finally, we studied the cytotoxic effect of the conjugate in co-culture of HMFG1-positive and-negative cell lines (HT 1376 and U87MG cells). We demonstrated that the rate of surviving cells corresponds well to the percentage of U87MG (HMFG1-negative) cells in the flask. Our findings indicate that ADEPT is more effective than non-directed enzyme activation of a prodrug and can result in a non-toxic cancer therapy.

Amygdalin↗
PubMedDate not supplied

Amygdalin metabolism and effect on reproduction of rats fed apricot kernels.

Diets containing 10% ground apricot kernels were fed to young and breeding male and female Sprague-Dawley rats. The kernels werE obtained from 35 specific apricot cultivars and divided into groups containing low amygdalin (less than 50 mg cyanide per 100 g), moderate amygdalin (100-200 mg cyanide per 100 g), or high amygdalin (more than 200 mg cyanide per 100 g). Growth of young male rats was greatest in the low- or moderate-amygdalin group which may indicate only that they were more sensitive to the bitter taste of the kernels with high amygdalin contents. In female rats, but not males, liver rhodanese activity and thiocyanate (SCN) blood levels were increased with the high-amygdalin diet, but both male and females efficiently excreted thiocyanate, indicating efficient detoxication and clearance of cyanide hydrolyzed from the dietary amygdalin. No changes in blood chemistry were observed. Although parturition and 3-d survival indices were poor in pups from dams fed a basal semisynthetic diet, offspring of breeding rats fed the high-amygdalin diet for 18 wk had lower 3-d survival indices, lactation indices, and weaning weights than those in the low-amygdalin group. This may indicate that the cyanide present in the milk may not be efficiently detoxified to SCN and excreted by neonates.

Amygdalin↗
PubMed1986

Intestinal first pass metabolism of amygdalin in the rat in vitro.

The intestinal first pass metabolism of amygdalin has been investigated in rat small intestine in vitro. The results show that amygdalin is hydrolyzed to prunasin, essentially in the wall of the proximal jejunum. This specific beta(1-6)hydrolytic cleavage of the terminal glucose residue is pH-dependent and can be inhibited by glucono-delta-lactone, a potent inhibitor of the lysosomal beta-glucosidase of the rat intestine. No substrate competition between phloridzin and lactose vs amygdalin was noted. None of the more common soluble beta- or alpha-enzymatic activities of mammalian intestine (alpha-glucosidase, alpha-amylase) or mammalian liver (beta-galactosidase, beta-glucuronidase) were capable of catalyzing the hydrolysis of the terminal glucose from amygdalin at pH's 5.0, 7.0 or 9.0. Furthermore, no metabolic activity of isolated rat livers toward amygdalin and prunasin was observed within two hours of recirculating perfusion. However, cecal contents of conventional rats, exhibited both amygdalin- and prunasin-hydrolyzing activities. The resulting mandelonitrile dissociates spontaneously into cyanide and benzaldehyde. Therefore, our findings indicate that metabolism of amygdalin to prunasin occurring in the proximal part of jejunum is apparently mediated by enzymatic beta(1-6)glucosidase activity of the gut wall. In contrast, the toxicity of amygdalin due to the release of cyanide obviously requires microbiological activities of the gut flora.

Amygdalin↗
PubMed1985

On the metabolism of amygdalin. 1. The LD50 and biochemical changes in rats.

The mean lethal dose (LD50) of amygdalin in rats was found to be 880 mg/kg body weight (BW) by oral administration. However, when 600 mg/kg BW was administered orally with beta-glucosidase, all the rats died. Total and Mg ATPase activities of the heart decreased with increasing levels of administered amygdalin. When 200 mg/kg BW amygdalin was administered 2.3 mg (11.7% of the dose) was excreted intact over 48 h. Amygdalin, 7.4 mg (18.5% of the dose) was excreted when the dose was 400 mg/kg BW, while 7.5 mg (12.4% of the dose) was excreted as intact amygdalin when the dosage was increased to 600 mg/kg BW. Thiocyanate excreted within the same 48-h period was 7.0, 9.1, and 9.5 mumol representing 18, 11.2, and 7.8% of the 200, 400, and 600 mg/kg BW oral dosage, respectively. With 300 mg/kg BW amygdalin administered intraperitoneally, 4.1 mg amygdalin and 3.9 mumol thiocyanate representing 13.7 and 6.5% of the dose, respectively, was excreted. Excretion of intact amygdalin and thiocyanate was uniform when the dose was low (200 mg), but with higher doses over 70% of the excreted products were detected in the urine during the first 24 h.

Adenosine Triphosphatases↗
PubMedDate not supplied

Blood cyanide levels in mice after administration of amygdalin.

Oral doses of amygdalin and intraperitoneal (i.p.) doses of potassium cyanide (KCN) in the near-lethal range were administered to CD2F1 female mice. Blood cyanide levels were then measured as a function of time. The maximum cyanide level after amygdalin administration was reached at about 11/2 to 2 h and was within the range of values seen after KCN administration. Behaviour of mice correlated with the time of maximum blood cyanide level. Acute distress was observed at times when the cyanide level was highest. There was great variability in the nature and magnitude of the response in individual mice. The ability of the contents of various regions of the gastrointestinal tract and of tumour tissue to release cyanide from amygdalin was assessed. Stomach and upper intestine had little activity while the lower end and the faeces released large amounts. Again, there was a large variation between mice. These results are interpreted to mean that enteric contents are primarily responsible for the release of cyanide from ingested amygdalin. Freshly minced tumour tissue released negligible amounts of cyanide. Ten-fold higher doses of amygdalin administered i.p. produced very small increases in blood cyanide levels and no toxic behaviour. The doses used are comparable to doses which might be ingested by patients receiving oral amygdalin or Laetrile and indicate that oral amygdalin is potentially extremely dangerous.

Administration, Oral↗
PubMed1981

Pharmacology of amygdalin (laetrile) in cancer patients.

Plasma and urine concentrations of amygdalin, whole-blood concentrations of cyanide, and thiocyanate concentrations in serum and urine were determined in cancer patients following intravenous (4.5 g/m2) and oral (500-mg tablet) administration of amygdalin. To measure low plasma concentrations of amygdalin following oral administration a GC/MS assay was developed. Following intravenous administration, concentrations of parent drug as high as 1,401 microgram/ml were observed, with no increase in plasma concentrations of cyanide or serum concentrations of thiocyanate. Plasma elimination of amygdalin was best described by a two-compartment open model with a mean distributive phase half-life of 6.2 min, mean elimination phase half-life of 120.3 min, and mean clearance of 99.3 ml/min. Following oral administration of amygdalin, plasma concentrations were much lower, with peak values of less than 525 ng/ml. Cyanide concentrations increased to values as high as 2.1 microgram/ml whole blood. Thiocyanate concentrations did not increase for several days, plateauing at values as high as 38 microgram/ml serum. Ingestion of almonds by two patients taking oral amygdalin increased cyanide concentrations compared with values obtained after oral amygdalin alone.

Administration, Oral↗
PubMed1982

The pharmacokinetics of amygdalin.

Amygdalin (D-mandelonitrile-beta-D-gentiobioside) is a cyanogenic glycoside claimed to show anti-cancer activity, sold under the incorrect name "Laetrile". For a sensible discussion of its alleged activity and its established toxicity it is necessary that its fate in the organism is known. The pharmacokinetics of amygdalin have been investigated in the Beagle dog after both intravenous and oral administration. The excretion of amygdalin has also been studied in the rat. Amygdalin concentrations were determined by high performance liquid chromatography in plasma ultrafiltrate and urine. The pharmacokinetics of amygdalin after intravenous administration were compared with those of diatrizoate, a model substance for extracellular volume and glomerular filtration. The amygdalin clearance is significantly larger than that of diatrizoate. The volumes of distribution of both substance are the same. After oral administration only a few percents of the amygdalin dose are systemically available. A part of the oral dose is recovered from the urine as prunasin (D-mandelonitrile-beta-D-glucoside).

Administration, Oral↗
PubMed2004

Effect of amygdalin on the proliferation of hyperoxia-exposed type II alveolar epithelial cells isolated from premature rat.

The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in A-EC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 micromol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 micromol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 micromol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.

Amygdalin↗
PubMed1986

Comparative metabolism of linamarin and amygdalin in hamsters.

Rates of cyanide liberation resulting from hydrolysis of the cyanogenic glycosides linamarin, amygdalin and prunasin by a crude beta-glucosidase prepared from hamster caecum were studied in vitro. In addition, hamster blood cyanide and thiocyanate concentrations were determined at 0.5, 1, 2, 3 and 4 hr after an oral dose of 0.44 mmol linamarin or amygdalin/kg body weight. Plots of cyanide liberated v. time for linamarin and prunasin yielded straight lines. A similar plot for amygdalin was curvilinear, with the rate of cyanide release increasing with time. At 10(-3) M substrate concentrations, the average rates of hydrolysis of prunasin, amygdalin and linamarin were 1.39, 0.57 and 0.13 nmol/min/mg protein, respectively. Lineweaver-Burk plots yielded apparent Km and Vmax values of 3.63 X 10(-5) M and 0.35 nmol/min/mg protein, respectively, for amygdalin, and 7.33 X 10(-3) M and 1.04 nmol/min/mg protein, respectively, for linamarin. Blood cyanide concentrations following amygdalin treatment reached their highest level (130 nmol/ml) 1 hr after dosing and remained elevated until 3 hr after treatment. Blood cyanide concentrations following linamarin treatment reached their highest level (116 nmol/ml) after 3 hr and then declined immediately. Area under the blood cyanide concentration-time curve was 395 nmol-hr/ml for amygdalin and 318 nmol-hr/ml for linamarin. The results suggest a faster rate of enzymatic hydrolysis and cyanide absorption for amygdalin than for linamarin.

Amygdalin↗
PubMed2002

Development of quantitative extraction method of amygdalin without enzymatic hydrolysis from tonin(Persicae Semen) by high performance liquid chromatography.

Tonin(Persicae Semen) is the herb medicine that contains amygdalin as a major ingredient. Amygdalin in water is decomposed into benzaldehyde, HCN, and glucose by emulsin, a hydrolysis enzyme in tonin. A useful and practical method for the optimum extraction condition of amygdalin without enzymatic hydrolysis is required. The extraction yield of amygdalin of natural formula tonin was 0.1% from crude powders, 1.4% from small pieces, 3.5% from half pieces and 2.4% from whole pieces. The extraction yield of amygdalin of outer shell-eliminated tonin was 0.3% from crude powders, 1.4% from small pieces, and 3.5% from half pieces and whole pieces respectively. The extraction yield of amygdalin was most high when using the size larger than half.

Amygdalin↗
PubMed2005

Quantitative determination of amygdalin epimers from armeniacae semen by liquid chromatography.

D-amygdalin and its conversion product, neoamygdalin, were quantitatively analyzed on reverse-phase, high-performance liquid chromatography with an optimized eluent of 10 mM sodium phosphate buffer (pH 3.1) containing 8.5% acetonitrile. Linearity between concentrations and detector responses was obtained in the range from 0.05 to 0.5 mM. The detection limits for D-amygdalin and neoamygdalin were approximately 5 microM per injected amount. Armeniacae semen contains not only amygdalin but also emlusin, which is an enzyme that hydrolyzes amygdalin. When extracting amygdalin from a whole piece of armeniacae semen in boiling water, there was almost no influence of emulsin; which increased the extraction efficiency. However, conversion of d-amygdalin into neoamygdalin at high temperature was found. In this report, we solved this problem by using 4% citric acid as an extractant. This solution also prevented the extraction process from being affected by emulsin. In addition, the extraction efficiency remained the same as that when methanol was used as an extractant, regardless of the cutting size.

Amygdalin↗
PubMed1984

Preparative and analytical separation of amygdalin and related compounds in injectables and tablets by reversed-phase HPLC and the effect of temperature on the separation.

Previous HPLC procedures for amygdalin and related compounds in injectables and tablets were either time consuming or produced inadequate separations of D-amygdalin and its epimer. A study of the effects of temperature on the separation resulted in development of an HPLC method for amygdalin and some related compounds, using water as the mobile phase at 15 degrees C. Multimilligram quantities of amygdalin and related compounds were separated by this preparative procedure. The aqueous mobile phase allows the compounds to be recovered by simple lyophilization of the sample after elution. This permitted the carbon-13 NMR spectrum of the isolated aglyconic epimer of amygdalin to be reported for the first time. D-amygdalin, its L-mandelonitrile epimer (D-epiamygdalin), their hydrolysis products (the epimeric amides and epimeric acids), and the sugar gentiobiose were separated by the method.

Amygdalin↗