Authenticity control of pine sylvestris essential oil by chiral gas chromatographic analysis of α-pinene.

Numerous terpenes present in essential oils (EOs) display one or more chiral centers. Within the same genus the enantiomeric ratio of these compounds can be different. Thus, the determination of enantiomers is a valuable tool to evaluate authenticity and quality of EOs. In here, the terpene profile of primary and commercial pine EOs was analyzed by conventional and chiral gas chromatography coupled to a flame ionization detector. The enantiomeric excess of ( ±)-α-pinene was determined and significant differences between primary and commercially available EOs were observed. Primary EOs of Pinus sylvestris L. showed a positive enantiomeric excess of (+)-α-pinene whereas commercial EOs labeled as P. sylvestris L. exhibited an enantiomeric excess of (-)-α-pinene. Thus, chiral analysis provides useful information on the authenticity of pine EOs and allows to uncover possible mislabeling, the use of the wrong herbal substance and sources of adulteration in pine oil.

α-Pinene: A never-ending story.

α-Pinene represents a member of the monoterpene class and is highly distributed in higher plants like conifers, Juniper ssp. and Cannabis ssp. α-Pinene has been used to treat respiratory tract infections for centuries. Furthermore, it plays a crucial role in the fragrance and flavor industry. In vitro assays have shown an enantioselective profile of (+)- and (-)-α-pinene for antibacterial and insecticidal activity, respectively. Recent research has used pre-validated biological structures to synthesize new chemical entities with pharmacological and herbicidal activities. In summary, this review focuses on recent literature covering synthetic pathways of flavor compounds and scaffold hopping based on the α-pinene core domaine, as well as the (enantioselective) activities of α-pinene. Recent approaches for authenticity control of essential oils based on their enantiomeric profile are also presented.

Verification of Chromatographic Profile of Primary Essential Oil of Pinus sylvestris L. Combined with Chemometric Analysis.

Chromatographic profiles of primary essential oils (EO) deliver valuable authentic information about composition and compound pattern. Primary EOs obtained from Pinus sylvestris L. (PS) from different global origins were analyzed using gas chromatography coupled to a flame ionization detector (GC-FID) and identified by GC hyphenated to mass spectrometer (GC-MS). A primary EO of PS was characterized by a distinct sesquiterpene pattern followed by a diterpene profile containing diterpenoids of the labdane, pimarane or abietane type. Based on their sesquiterpene compound patterns, primary EOs of PS were separated into their geographical origin using component analysis. Furthermore, differentiation of closely related pine EOs by partial least square discriminant analysis proved the existence of a primary EO of PS. The developed and validated PLS-DA model is suitable as a screening tool to assess the correct chemotaxonomic identification of a primary pine EOs as it classified all pine EOs correctly.

Derivatization-free determination of short-chain volatile amines in human plasma and urine by headspace gas chromatography-mass spectrometry.

BACKGROUND: Short-chain volatile amines (SCVA) are an interesting compound class playing crucial roles in physiological and toxicological human settings. Dimethylamine (DMA), trimethylamine (TMA), diethylamine (DEA), and triethylamine (TEA) were investigated in detail. METHODS: Headspace gas chromatography coupled to mass spectrometry (HS-GC-MS) was used for the simultaneous qualitative and quantitative determination of four SCVA in different human body fluids. Four hundred microliters of Li-heparin plasma and urine were analyzed after liberation of volatile amines under heated conditions in an aqueous alkaline and saline environment. Target analytes were separated on a volatile amine column and detected on a Thermo DSQ II mass spectrometer scheduled in single ion monitoring mode. RESULTS: Chromatographic separation of selected SCVA was done within 7.5 minutes. The method was developed and validated with respect to accuracy, precision, recovery and stability. Accuracy and precision criteria were below 12% for all target analytes at low and high levels. The selected extraction procedure provided recoveries of more than 92% from both matrices for TMA, DEA and TEA. The recovery of DMA from Li-heparin plasma was lower but still in the acceptable range (>75%). The newly validated method was successfully applied to plasma and urine samples from healthy volunteers. Detected concentrations of endogenous metabolites DMA and TMA are comparable to already known reference ranges. CONCLUSION: Herein, we describe the successful development and validation of a reliable and broadly applicable HS-GC-MS procedure for the simultaneous and quantitative determination of SCVA in human plasma and urine without relying on derivatization chemistry.

Quantification of hydrolyzed peptides and proteins by amino acid fluorescence.

Reliable quantification of peptides and proteins is essential for drug discovery. We report the successful development and validation of an accurate and broadly applicable high performance liquid chromatography hyphenated to fluorescence detector procedure for the quantitative determination of the aromatic amino acids tyrosine, phenylalanine, and tryptophan, without relying on derivatization chemistry. Using ion-pair chromatography, fluorescent amino acids were clearly separated within 10 minutes. The hydrolysis of peptides was performed under acidic and heated conditions to yield the monomeric building blocks. Various protecting agents were tested to ensure tryptophan stability. The presented analytical method accurately (>95%) quantifies all fluorescent residues. The power of the method was confirmed by correct quantification of protein reference standard to 98.6% over all fluorescence traces. The method allowed us to identify pre-analytical differences between the nominal and actual concentrations of 12 peptide solutions. Salt formation, weighing errors, and other pre-analytical pitfalls resulted in noteworthy differences of up to 85% between the indicated and actual concentration of peptide solutions, subsequently leading to false positive or negative interpretation of activity data. Finally, only one solution is needed to perform quantification as well as UV-purity tests and can further be used as stock solution for activity testing.

Plasma Concentrations of Trimethylamine-N-oxide Are Directly Associated with Dairy Food Consumption and Low-Grade Inflammation in a German Adult Population.

BACKGROUND: Trimethylamine-N-oxide (TMAO) is a metabolite of carnitine, choline, and phosphatidylcholine, which is inversely associated with survival of cardiovascular disease (CVD) patients. OBJECTIVE: We examined the associations of diet with plasma concentrations of TMAO, choline, and betaine and the associations of TMAO with plasma concentrations of various cytokines. METHODS: Plasma TMAO, choline, and betaine concentrations were measured using LC-high resolution mass spectrometry in 271 participants, ≥18 y old, of the Second Bavarian Food Consumption Survey, conducted in 2002 and 2003. Food consumption was assessed using at least two 24-h dietary recalls. Cytokines were measured in plasma with enzyme-linked immunosorbent assays. Geometric mean concentrations of TMAO, choline, and betaine by categories of meat, dairy food, egg, and fish consumption were computed, adjusted for sex, age, and BMI. Multivariable-adjusted geometric mean concentrations of cytokines [tumor necrosis factor-α (TNF-α), soluble TNF receptors (sTNF-R) p55, sTNF-R p75, interleukin-6 (IL-6), and C-reactive protein (CRP)] were computed by quartiles of TMAO concentration using general linear models. RESULTS: Meat, egg, or fish consumption was not associated with TMAO, choline, or betaine concentrations (all P-trend ≥ 0.05). With increases in milk and other dairy food consumption, the plasma TMAO concentration increased [geometric mean bottom quartile of milk consumption: 2.08 µM (95% CI: 1.69, 2.57 µM); compared with top quartile: 3.13 µM (95% CI: 2.56, 3.84 µM); P-trend = 0.008]. Participants in the top TMAO quartile had higher plasma concentrations of TNF-α, sTNF-R p55, and sTNF-R p75 than participants in the bottom quartile (percentage difference ranging between 14.4% and 17.3%; all P-trend < 0.05), but there were no differences in plasma concentrations of CRP and IL-6 (all P-trend ≥ 0.05). CONCLUSIONS: Results of this study conducted among healthy adults from the general population do not indicate a strong effect of diet on plasma concentrations of TMAO, choline, or betaine, with the exception of a positive association between dairy food consumption and plasma TMAO concentrations. Also, plasma TMAO concentrations were positively associated with inflammation. Whether habitual diet is strongly linked to the plasma TMAO concentration, a potential marker of CVD risk, needs to be determined in further studies.

Plasma levels of trimethylamine-N-oxide are confounded by impaired kidney function and poor metabolic control.

BACKGROUND: After ingestion of phosphatidylcholine, l-carnitine or betaine, trimethylamine-N-oxide (TMAO) is formed by gut microbiota and liver enzymes. Elevated TMAO plasma levels were associated with increased cardiovascular risk and other diseases. Also betaine and choline itself were recently associated with increased cardiovascular risk. METHODS: A newly developed LC-HRMS method was applied to measure the plasma concentrations of TMAO, betaine and choline in a cohort of 339 patients undergoing coronary angiography for the evaluation of suspected coronary artery disease. RESULTS: Betaine concentrations in males were significantly higher than in females (42.0 vs. 35.9 µmol/L; p < 0.001). Plasma concentrations of TMAO but not of betaine or choline were higher in patients with diabetes compared to euglycemic patients (2.39 vs. 0.980 µmol/L; p = 0.001) as well as in patients with metabolic syndrome as compared to patients without metabolic syndrome (2.37 vs. 1.43 µmol/L; p = 0.002). Plasma concentrations of TMAO or choline increased significantly with decreasing renal function (Spearman's rho: -0.281; p < 0.001). However, plasma levels of TMAO or betaine were associated with neither a history of myocardial infarction nor the angiographically assessed presence of coronary heart disease, nor incident cardiovascular events during 8 years of follow-up. Plasma levels of choline were significantly lower in patients with a history of acute myocardial infarction as compared to those without such history (10.0 vs. 10.8 µmol/L; p = 0.045). CONCLUSIONS: Plasma levels of TMAO are confounded by impaired kidney function and poor metabolic control but are not associated with the history, presence or incidence of symptoms or events of coronary heart disease.