A Colorimetric Method for the Rapid Estimation of the Total Cannabinoid Content in Cannabis Samples.

A colorimetric method for the estimation of the total content of cannabinoids in cannabis samples is proposed. The assay is based on the reaction of these compounds with the reagent Fast Blue B (FBB), which has been immobilized into polydimethylsiloxane (PDMS). The reaction and detection conditions have been established according to the results obtained for the individual cannabinoids Δ9-tetrahydrocannabidiol (THC), cannabidiol (CBD), and cannabinol (CBN), as well as for ethanolic extracts obtained from cannabis samples after ultrasonication. In contact with the extract and under basic conditions, the reagent diffuses from the PDMS device, producing a red-brown solution. The absorbances measured at 500 nm after only 1 min of exposure to the FBB/PDMS composites led to responses proportional to the amounts of the cannabinoids in the reaction media. Those absorbances have been then transformed in total cannabinoid content using CBD as a reference compound. The potential utility of the proposed conditions has been tested by analyzing different cannabis samples. The selectivity towards other plants and drugs has been also evaluated. The present method is proposed as a simple and rapid alternative to chromatographic methods for the estimation of the total content of cannabinoids.

The Application of Voltammetric Analysis of Δ(9) -THC for the Reduction of False Positive Results in the Analysis of Suspected Marijuana Plant Matter.

The development of methodologies using inexpensive, fast, and reliable instrumention is desirable in illicit drug analysis. The purpose of this study was based on cyclic voltammetry technique to differentiate the electrochemical behavior of ∆(9) -THC, the psychoactive substance in marijuana, and five different extract plants to yield false positive results after analysis protocol for cannabinoids using thin-layer chromatography and Fast Blue B salt. After applying a deposition potential of -0.5 V in a glassy carbon working electrode, the results indicated an anodic peak current at 0.0 V versus Ag/AgCl after addition of ∆(9) -THC solution in the electrochemical cell, and limits of detection and quantification were 1.0 ng mL(-1) and 3.5 ng mL(-1) , respectively. Other interfering plants showed distinct amperometric responses. This methodology was useful to detect ∆(9) -THC even in the presence of the Fast Blue B salt, which avoided false positive results for all the studied extract plants.

The Uncontrolled Sialylation is Related to Chemoresistant Metastatic Breast Cancer.

Among the scientific communities, there is a convergence of results supporting a direct relationship between dysregulated sialylation and poor prognosis in many human cancers. For this reason, we have retrospectively investigated 169 cases of invasive ductal carcinoma of the breast, coming from female patients aged between 31 and 76 years old. The whole series was subdivided into two prognostic groups: the first group consisted of 138 patients, who showed a post-treatment survival time more than 5 years, while the second group was made up by 31 patients, died within 5 years despite of chemotherapy. All the surgical specimens were fixed in 10 % neutral buffered formalin, paraffin embedded and, then, submitted to routinely haematoxylin/eosin staining and to a further histochemical (Alcian Blue, DDD-Fast Blue B, Mercury Orange), immunohistochemical (ST3GAL5 sialyltransferase, Ki67, c-erbB2, ER, PR) and chemico-elemental characterization. In the 31 cases of breast cancer belonging to the second group, an overexpression of sialomucins and sialyltransferases has been detected. Our results lead us to support that in aggressive chemoresistant breast cancers, the altered expression of sialic acid, due to an uncontrolled sialylation, creates an excessive negative charge on cell membranes, which stimulates repulsion between neoplastic cells and their subsequent access into the blood stream. This event implies an early metastatization and a rapid disease progression with fatal outcome. The early application of Alcian Blue stain on diagnostic biopsies of breast cancer is able to cheaply reveal the sialomucin accumulations, providing for the disease course.

Development and validation of a micromethod for fast quantification of 5-n-alkylresorcinols in grains and whole grain products.

A 96-well plate micromethod was developed to measure 5-n-alkylresorcinols (5nARs) in cereal grains and food derived products. The 5nARs reacted in alkaline alcoholic medium with Fast Blue RR ½ZnCl2 salt to yield coloured azo-derivatives. The highest sensitivity for 5nARs was obtained at 490 nm with 0.025% ethanolic Fast Blue RR and 5% K2CO3. This reaction showed good linearity for olivetol (0.05-0.20 µg). Contents of 5nARs determined in cereal grains and derived products by the new Fast Blue RR micromethod were highly correlated (R(2)=0.9944) with those obtained by a Fast Blue B method currently used. A Bland-Altman analysis indicated a small positive bias near to zero (R(2)=0.0401), suggesting that the methods can be interchangeably used. The new reaction is completed in 15 min and the coloured products are read within the 15 min after completion. The micromethod offers a fast analysis of 5nARs in cereal grains and derived products with low consumption of reagents and solvents.