Carbon isotope ratio of endogenous urinary steroids of the Cuban population of athletes studied for doping purposes.

The aim of this work was to validate the gas chromatography/combustion/isotope ratio mass spectrometry method in Havana Antidoping Laboratory and verify its implementation with a study of the Cuban population. The method was precise and accurate inside the linear working range; the limit of quantification and the uncertainty were compliant with TD2019IRMS. The study of the Cuban population showed no differences in δ13 C values between females and males. Only three values of Δδ13 C showed significant differences between sexes (PD-T, OHA-T, and 11-keto-Et-T). The values of δ13 C between -17.8‰ and -21.2‰ (upper and lower limits based on normal distribution) were consistent with other populations where C4 plant derivatives prevail in the diet.

"Application of the ultra micro analytical system (SUMA) technology for the detection of urinary hCG in antidoping control".

The Ultra Micro Analytical System (SUMA) is an ELISA-based analytical platform, developed andmanufactured by the Cuban Immunoassay Center (IC), which is primarily used in clinical medicine applications. In this article, we describe the validation of the UMELISA HCG kits, which are based on SUMA, as a pre-screening procedure for the detection of human Chorionic Gonadotrophin (hCG) in urine for anti-doping purposes. Validation of assay performance parameters showed satisfactory results, in accordance with the criteria established by the World Anti-Doping Agency (WADA): intra-assay repeatability (6.7-9.7%), inter-assay reproducibility (7.8-10.5%), accuracy (91-98%), limit of detection (2.7 IU/L), and linearity. Relative sensitivity and specificity and Predictive Positive and Negative Values were used to evaluate the Efficacy showing a value of 97.6%. A Kappa Index analysis was applied to check agreement with the commercially available, reference assay COBASe411 (Roche), which is often applied in WADA-accredited anti-doping laboratories for measurement of intact (heterodimeric) hCG in urine. UMELISA HCG kits are considered as fit for anti-doping control purposes.

Chemical profile and anti-leishmanial activity of three Ecuadorian propolis samples from Quito, Guayaquil and Cotacachi regions.

Three propolis samples were collected from different regions of Ecuador (Quito, Guayaquil and Cotacachi) and their methanolic extracts were prepared. Preliminary information supplied by TLC and NMR data, allowed us to define two main types of propolis: Cotacachi propoli sample (CPS), rich in flavonoids and Quito and Guayaquil samples (QPS and GPS) containing triterpenic alcohols and acetyl triterpenes as the main constituents. Two different approaches based on RP-HPLC preparative procedure and NMR structural determination (CPS) and GC-MS analysis (QPS and GPS) were successfully used for the chemical characterization of their major compounds. All three propolis extracts were able to inhibit Leishmania amazonensis growth but propolis sample rich in flavonoids was the most active (IC50=17.1±1.7µg/mL). In the literature this is the first study on propolis from Ecuador.

Validación de un método por CLAR para la cuantificación de L-prolina en la tintura al 20 por ciento de Murraya paniculata L. Jack / Validation of a high performance liquid chromatography method for quantitation of L-proline in 20 percent tincture from Murraya paniculata L. Jack

INTRODUCCIÓN: la búsqueda de técnicas analíticas para el control de la calidad de los medicamentos constituye un aspecto de gran interés en el campo farmacéutico, más si van dirigidas al estudio del o los marcadores químicos de las plantas medicinales, sus extractos y fitomedicamentos. OBJETIVO: validar un método de cromatografía líquida de alta resolución (CLAR) para la determinación cuantitativa del aminoácido L-prolina como sustancia marcador en la tintura de Murraya paniculata L. Jack. MÉTODOS: en el método por CLAR, la separación se realizó en una columna C-18 (UP5ODB-150/046), se utilizó como fase móvil una mezcla de solución buffer fosfato, pH ajustado a 2,4 y acetonitrilo (70:30 v/v), con una velocidad de flujo de 0,6 mL/min, modo isocrático, con detección ultravioleta a 440 nm. El volumen de inyección de la muestra fue de 20 µL. El método fue validado según la categoría I, siguiendo las exigencias internacionales. RESULTADOS: la curva de calibración fue lineal en el rango de concentraciones ensayadas (30 a 375 µg/mL), se observó una buena precisión con coeficientes de variación menores del 2 por ciento. Los valores de recobrado estuvieron dentro de los límites establecidos para los métodos cromatográficos (98-102 por ciento). Se demostró la especificidad del método, al no presentarse interferencias de picos adicionales en la zona de elusión del compuesto de interés (L-prolina). CONCLUSIONES: el método analítico por CLAR, validado para la cuantificación del aminoácido L-prolina en la tintura de M. paniculata, demostró ser lineal, preciso, exacto y específico bajo las condiciones de estudio(AU)

INTRODUCTION: the search for analytical methods that may monitor the quality of drugs is an issue of great interest in the pharmaceutical field, even more if they are directed to studying chemical markers of medicinal plants, their extracts and phytomedicines. OBJECTIVE: to validate a high-resolution liquid chromatography (HPLC) method for the quantitative determination of the L-proline amino acid as a marker substance in Murraya paniculata L. Jack tincture. METHODS: in the HPLC, the separation was performed on a C-18 (UP5ODB-150/046) column, with a mixture of phosphate buffer solution, pH adjusted to 2.4 and acetonitrile (70:30 v/v) used as mobile phase, the flow rate was 0.6 mL/min, isocratic mode with UV detection set at 440 nm. The injection volume of the sample was 20 µL. The method was validated according to category I, following international requirements. RESULTS: the calibration curve was linear over the concentration range tested (30-375 mg/mL), good precision was observed with a variation coefficient less than 2 percent. Recovery values were within the limits for chromatographic methods (98-102 percent). The method was specific since there was no-interference by additional peaks in the elution zone of the compound in question (L-proline). CONCLUSIONS: the HPLC analytical method, validated for the quantification of L-proline amino acid in M. paniculata tincture, proved to be linear, precise, accurate and specific under the study conditions(AU)

Caracterización química por cromatografía de gases/espectrometría de masas de dos extractos obtenidos de Phyllanthus orbicularis HBK / Chemical characterization using gas chromatography/mass spectrometry of two extracts from Phyllanthus orbicularis HBK

El objetivo del presente trabajo consistió en la caracterización química por cromatografía de gases/espectrometría de masas de 2 extractos obtenidos de Phyllanthus orbicularis HBK, para lo cual se llevó a cabo un método de extracción por maceración con n-hexano y acetato de etilo, a fin de obtener los extractos correspondientes. El estudio del extracto hexánico permitió identificar 17 componentes y resultaron predominantes estructuras del tipo hidrocarbonada, entre ellas, el ciclooctacosano como componente mayoritario. En el extracto de acetato de etilo se identificaron 19 compuestos y constituyeron los terpenoides las estructuras mayoritarias, aunque el más abundante resultó ser el esterol ã-sitosterol. Los compuestos identificados se informan por primera vez para la especie

The objective of this paper was the chemical characterization of two extracts from Phyllanthus orbicularis HBK through gas chromatography/mass spectrometry. To this end, maceration with N-hexane and ethyl acetate was used to obtain the respective extracts. The study of the hexane extract identified 17 components in which hydrocarbonate structures prevailed, mainly cyclooctacosane. In the ethyl acetate extract, 19 compounds were detected, being the terpenoids the predominant, although the most abundant was sterol ã-sitosterol. For the first time, the identified compounds are reported for this species

Studies on the constituents of yellow Cuban propolis: GC-MS determination of triterpenoids and flavonoids.

In this study, on the basis of the information supplied by NMR and HPLC-PDA data, we reported a quali-quantitative GC-MS study of 19 yellow Cuban propolis (YCP) samples collected in different regions of Cuba. The profiles of YCP samples allowed us to define two main types of YCP directly related to their secondary metabolite classes: type A, rich in triterpenic alcohols and with the presence of polymethoxylated flavonoids as minor constituents, and type B, containing acetyl triterpenes as the main constituents. For the first time, triterpenoids belonging to oleanane, lupane, ursane, and lanostane skeletons were reported as major compounds in propolis. Also, the presence of polymethoxylated flavones or flavanones was found for the first time in propolis.

GC-MS determination of isoflavonoids in seven red Cuban propolis samples.

In the present study, the phenolic composition analysis of seven red varieties of propolis, collected in different regions of Cuba, was evaluated by gas chromatography/mass spectrometry (GC-MS). Seventeen compounds were identified in all samples by the interpretation of their mass spectra. This appears to be the first report on the GC-MS analysis of isoflavonoids in the propolis. The results confirmed the presence of the main isoflavonoids isolated previously and suggested the general structure for the other five isoflavonoids. Vestitol, 7-O-methylvestitol, and medicarpin were present in high amounts in all propolis samples analyzed. This result indicates that propolis samples rich in isoflavonoids are not exclusively found in Pinar del Rio province and proves that GC-MS technique is a useful and alternative tool for the chemical analysis of tropical red propolis.