Rapid HPLC screening method for contaminants found in implicated L-tryptophan associated with eosinophilia myalgia syndrome and adulterated rapeseed oil associated with toxic oil syndrome

Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA₁-343) and linear (AAA₂-343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA₁-343 and AAA₂-343. We structurally characterized eight new AAA₁-XXX/AAA₂-XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA₁-315; n-octanoic acid (n-C8:0) for AAA₂-315; 6-methyloctanoic acid (anteiso-C9:0) for AAA₁-329; n-nonanoic acid (n-C9:0) for AAA₂-329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA₁-385; n-tridecanoic acid (n-C13:0) for AAA₂-385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA₁-399; and n-tetradecanoic acid (n-C14:0) for AAA₂-399. The concentration levels for these contaminants were estimated to be 0.1-7.9 μg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed.

Does 5-hydroxytryptophan cause acute and chronic toxic perturbations in rats?

In 1989, an epidemic of eosinophilia-myalgia syndrome (EMS) occurred in the United States that was attributed to contaminated l-tryptophan (LT). Features of tryptophan-induced EMS included debilitating myalgia and marked peripheral eosinophilia. Although the contaminant(s) was found only in the product produced by a single manufacturer (Showa Denko), all LT was withdrawn from the market and replaced by 5 hydroxytryptophan (5HTP). The belief was that the latter should not contain the implicated contaminant(s), because it was manufactured by a process entirely different from the banished LT. Nevertheless, in 1994 a case diagnosed as EMS appeared. Although the exact causative factor(s) in LT and the possible 5-HTP-induced EMS are uncertain, many reported finding "Peak E" in contaminated LT and the presence of "Peak X" in the 5-HTP of the 1994 case. The latter finding led some to assume that Peak X was a potential pathological agent in 5-HTP that might cause future cases of EMS. To determine whether 5-HTP could cause EMS, we followed 120 male Sprague-Dawley rats, 7 to 8 weeks of age (body weight 200-250 g), for 1 year. They were divided into three groups of 40. One group acted as control, drinking only water; a second group received a low dose of 5-HTP in their drinking water (87.5 mg/dL); and the last group drank a high dose of 5-HTP, 875 mg/dL. No significant differences in the body weights of these three groups of animals were observed over the year. After 2 months, systolic blood pressures (SBP) in the 5-HTP groups were significantly lower for the duration of the study. At the end of 12 months, SBP of the control group averaged 140 mm Hg, the low-dose 5-HTP group averaged 133 mm Hg, and the high-dose group averaged 125 mm Hg. Even though enough 5-HTP was given to cause a physiological response, no significant differences were found in the hematological values, including eosinophil count. Also, no significant differences were found in hepatic and renal values. In the histological studies, no treatment-related changes were noted in the hearts, livers, pancreases, leg striated muscles, and small intestines. In particular, there was no evidence of eosinophilic infiltration and fascial/perimysial inflammation. Accordingly, no significant evidence of EMS was seen in rats receiving high-dose 5-HTP for 1 year.

Mood effects of the amino acids tryptophan and tyrosine: 'Food for Thought' III

OBJECTIVE

Reflecting increased scientific interest in any nutritional contribution to the onset and treatment of mood disorders, we overview research into two neurotransmitter precursors - the amino acids tryptophan and tyrosine - particularly examining whether any deficiency increases risk to depression and whether those amino acids have any antidepressant properties.

METHOD

The theoretical relevance of the two amino acids was overviewed by considering published risk and intervention studies, technical papers and reviews.

RESULTS

There is some limited evidence, suggesting that depressed patients, especially those with a melancholic depression, have decreased tryptophan levels. Whether such findings reflect a causal contribution or are a consequence of a depressed state remains an open question. There is a small database supporting tryptophan preparations as benefitting depressed mood states. There is no clear evidence as to whether tyrosine deficiency contributes to depression, while the only randomized double-blind study examining tyrosine supplementation did not show antidepressant benefit.

CONCLUSION

Acute tryptophan depletion continues to provide a research tool for investigating the relevance of serotonin to depression onset. There is limited evidence that tryptophan loading is effective as a treatment for depression through its action of increasing serotonin production. Most clinical studies are dated, involve small sample sizes and/or were not placebo controlled. The development of the new serotonin reuptake inhibitor drugs seemingly signalled an end to pursuing such means of promoting increased serotonin as a treatment for depression. The evidence for tyrosine loading promoting catecholamine production as a possible treatment for depression appears even less promising, and depletion studies less informative.

Dietary supplements and herbal medicine toxicities-when to anticipate them and how to manage them

BACKGROUND

Dietary supplements and herbal medicines are gaining popularity in many developed countries.

AIMS

Although most can be used without any problem, serious toxicities do occur.

METHODS

Problems can be anticipated when they are used for non-traditional indications, at excessive dose, for prolonged duration, or by patients who are also on multiple modern pharmaceuticals. Problems should also be anticipated when these products claim to be able to relieve symptoms rapidly or when herbs with pronounced pharmacological effects or toxic components are used.

RESULTS

Resuscitation, symptomatic and supportive care are the most important aspects of management of toxicities from these products.

CONCLUSION

This article reviews when problems with these products can be anticipated and outlines a practical approach to management.

The effects of tryptophan depletion on mood and psychiatric symptoms

BACKGROUND

The number of studies using tryptophan depletion (TD) challenge has increased markedly in the past few years. Recently, a number of negative results have been published, implicating that the effect of TD on mood may be less consistent than previously thought.

METHODS

The literature on the mood effects of TD in psychiatric patients and healthy volunteers was reviewed.

RESULTS

TD has a mood-lowering effect in subgroups of recovered depressed patients, patients with seasonal affective disorder and vulnerable healthy subjects. The mood effect in former patients is of a different quality, however, than the effect in healthy subjects. Some recent negative studies in depression might be explained by insufficient lowering of plasma tryptophan levels. Preliminary evidence exists for an effect of TD on bulimia nervosa, autism, aggression and substance dependence.

CONCLUSIONS

The effects of TD on mood may be more consistent than suggested by a number of recent negative studies. Response to TD in recovered depressed patients is associated with prior treatment. However, even in SSRI-treated patients the relapse rates are not higher than 50-60%, which needs to be explained. The clinical usefulness of the response to TD in recovered patients (prediction of relapse after treatment discontinuation) and in symptomatic patients (prediction of treatment refractoriness) deserves more research attention. Further suggestions for future research include the cognitive effects of TD in recovered depressed patients and the effect of dietary habits on response to TD.

Structural characterization of case-associated contaminants peak C and FF in L-tryptophan implicated in eosinophilia-myalgia syndrome

We have characterized the structures of two case-associated contaminants of the Showa Denko L-tryptophan known to cause eosinophilia-myalgia syndrome (EMS). A combination of on-line accurate mass HPLC-electrospray ionization-mass spectrometry (LC-MS), HPLC-tandem mass spectrometry (LC-MS-MS) and HPLC-in source collision induced dissociation-MS-MS (LC-sCID-MS-MS) allowed the structure determination of both Peak C and FF. Peak C is identified as 3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo-[2-3b]-indole-2-carboxyl ic acid, whereas Peak FF is characterized as 2-(2-hydroxy-indoline)-tryptophan. Both contaminants contain indoline rings, and the significance of this finding is discussed.

On-line HPLC-tandem mass spectrometry structural characterization of case-associated contaminants of L-tryptophan implicated with the onset of eosinophilia myalgia syndrome

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA in 1989 was caused by the intake of L-tryptophan (Trp) produced from one manufacturer, Showa Denko K.K. of Japan. Six compounds present in the Trp were reported to be case-associated contaminants. However, three of these compounds, Peaks C, FF and AAA have remained unidentified. Here, we successfully employ on-line HPLC-electrospray ionization multistage mass spectrometry to structurally characterize Peak C and Peak FF. Peak C was determined by accurate mass-LC-MS to have a protonated molecular ion MH+ = 221.0919 with an empirical formula of C11H13N2O3. By comparing the LC-MS-MS spectra with authentic 5-OHTrp and other structurally similar compounds, as well as considering the chemical reactivity of the indole ring, the structure of Peak C was consistent with 3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo-[2,3-b]-indole-2-carboxy lic acid. Peak FF was also subjected to accurate mass-LC-MS and shown to have MH+ = 338.1524, corresponding to an empirical formula of C19H20N3O3. Comparison of the LC-MS-MS and LC-sCID-MS-MS of spectra derived from Peak FF with a previously characterized contaminant of Trp, namely P31, was consistent with Peak FF being 2-(2-hydroxy indoline)-Trp. Unlike the majority of the contaminants identified in EMS implicated tryptophan, both Peaks C and FF possess an indoline ring. This is significant since a case-associated contaminant found in 5-hydroxy-Trp also contains an indoline ring, and the chemical reactivity of this ring system may possibly play a role in the etiology of EMS.