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Salvia divinorum (Lamiaceae) is a herb native to Mexico where it is used by Mazatec shamans for spiritual and divination purposes. S. divinorum products are easily available to consumers and are used worldwide as legal highs because of the hallucinogenic effects caused mainly by salvinorin A. Highly popular videos and websites on the internet depicting the use of S. divinorum products have contributed to an increase in their consumption. Recent reports have highlighted the potential of these products to induce psychosis in consumers. In Mexico, dried leaf extracts of S. divinorum are sold in different strengths, claiming to correlate with increasing amounts of salvinorin A. In order to determine the variability of salvinorin A content between brands and to investigate possible correlation between brand strengths, this study sought to quantify salvinorin A in commercial products available in Mexico using an HPLC method. The HPLC analytical method showed a correlation coefficient R(2)>0.99, with LOD of 0.44 μg/mL and LOQ of 1.34 μg/mL. The retention time for salvinorin A was 23.09±0.95 min and the measured concentrations ranged between 8.32±0.65 and 56.52±3.77 mg/g dried leaf. The results for brand c did not show an agreement between the declared and the calculated amount of salvinorin A. Additionally, the emergence in Mexico of high strength salvia products (100×), the lack of regulation and the observed variability of salvinorin A content between brands of commercial legal highs products of S. divinorum could result in a health problem for consumers.

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Our work confirms the value of Ternstroemia sylvatica as an important anti-inflammatory and analgesic plant, whose mechanism seems to be associated to its antioxidant effects, and supports its uses in the Mexican traditional medicine.

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Since their introduction by E. L. Eliel nearly four decades ago, derivatives of 1,3-dioxane have proved useful in conformational analysis. Examples are discussed, where 5-polar substituents permit the evaluation of fundamental phenomena such as attractive and repulsive gauche effects, electrostatic interactions, and stereoelectronic effects. By the same token, 2-substituted 1,3-dioxanes, 1,3-dithianes, and 1,3-oxathianes are useful frameworks for the study of the anomeric effect and the associated structural and spectroscopic manifestations, such as the so-called Perlin effects. In view of the varied and essential involvement of metal ions and inorganic salts in biological processes, 5-substituted 1,3-dioxanes are presently being examined in the presence of Li + , Na + , K + , Ag + , Mg 2+ , Ca 2+ , Ba 2+ , and other cations, with the aim to increase the understanding of biomolecular properties in vivo. 1,3-DIOXANES AS MODEL SYSTEMS IN CONFORMATIONAL ANALYSISInterestingly, H. Sachse's proposal of a strain-free, chair-shaped cyclohexane [1a] was published in 1890, the same year A. Baeyer advanced the idea that cyclohexane was planar (and thus strained) [1b]. Baeyer's model was favored during several decades, owing to the fact that rapid-ring inversion prevented isolation of the axial and equatorial isomers that should originate in monosubstituted cyclohexane derivatives (Scheme 1).

The varied and essential involvement of metal ions and inorganic salts in biological and chemical processes motivated the present study where 5-carboxy- and 5-hydroxy-1,3-dioxanes are used as model frameworks for the evaluation of the conformational behavior of oxygen-containing receptors in the presence of Li(+), Na(+), K(+), Ag(+), Mg(2+), Ca(2+), Ba(2+), and Zn(2+). Thus, the position of equilibria, established by means of BF(3), between diastereomeric cis- and trans-5-substituted-2-phenyl-1,3-dioxanes, in solvent THF and in the presence of 0, 1, and 5 equiv of salt, has been determined. The observed Delta G(o) degrees values for the conformational equilibria of 5-carboxy-1,3-dioxane show that Ag(+), Li(+), and Ca(2+) complexation leads to increased stability of the axial isomer. In the case of the 5-hydroxy-1,3-dioxane, Mg(2+), Ag(+), and Zn(2+) are the metal ions that stabilize the axial conformer of the heterocycle upon association. Interpretation of the experimental observations was based on DFT molecular modeling studies at the Becke3LYP/6-31G* and Becke3LYP/6-31+G** levels of theory. Although gas-phase calculations give Delta E values that are too large when modeling equilibria involving ionic species in polar solution, the computational results confirm the structural and energetic consequences of metal cation coordination to the oxygen atom in carbonyls or ethers. The results derived from the present study contribute to our understanding of the chemical processes involved in molecular recognition and physiological events.

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