The dimerization of -tetrahydrocannabinolic acid A (THCA-A)

The renewed interest in dimeric salicylates as broad-spectrum anti-inflammatory and anti-diabetic agents provided a rationale to investigate the dimerization of the substituted salicylate -tetrahydrocannabinolic acid (THCA-A, ) as a strategy to solve its instability to decarboxylation and to generate analogues and/or pro-drugs of this native pre-cannabinoid. Activation of the carboxylic group with the DCC-HOBt-DMAP protocol afforded a high yield of the OBt ester , that was next converted into the highly crystalline di-depsidic dimer upon treatment with DMAP. The mono-depsidic dimer was also formed when the reaction was carried out with partially decarboxylated THCA-A samples. The structure of the depsidic dimers was established by spectroscopic methods and by aminolysis of into the pre-cannabinoid amide . Both dimers showed excellent shelf stability and did not generate significant amounts of -THC upon heating. However, only the didepsidic dimer activated PPAR-, the major target of pre-cannabinoids, but strong binding to serum proteins abolished this activity, also shielding it from the action of esterases.

The reaction of cinnamaldehyde and cinnam(o)yl derivatives with thiols

Spurred by the alleged relevance of the thia-Michael reaction in the bioactivity of various classes of cinnam(o)yl natural products and by the development of a quick NMR assay to study this reaction, we have carried out a systematic study of the "native" reactivity of these compounds with dodecanethiol and cysteamine as models, respectively, of simple thiols and reactive protein thiols that can benefit from iminium ion catalysis in Michael reactions. Cinnamoyl esters and amides, as well as cinnamyl ketones and oximes, did not show any reactivity with the two probe thiols, while cinnamaldehyde () reacted with cysteamine to afford a mixture of a thiazoline derivative and compounds of multiple addition, and with aliphatic thiols to give a single bis-dithioacetal (). Chalchones and their vinylogous C5-curcuminoid derivatives were the only cinnamoyl derivatives that gave a thia-Michael reaction. From a mechanistic standpoint, loss of conjugation in the adduct might underlie the lack of a native Michael reactivity. This property is restored by the presence of another conjugating group on the carbonyl, as in chalcones and C5-curcuminoids. A critical mechanistic revision of the chemical and biomedical literature on cinnamaldehyde and related compounds seems therefore required.

Bilberry Products: Modern Characterization of Commercial Extracts / 日本補完代替医療学会誌

Wild north European bilberry (Vaccinium myrtillus) is one of the richest botanical sources of anthocyanins, a class of molecules responsible for the color of fruits and characterized by a strong antioxidant activity.From a biological point of view, anthocyanins are endowed with several diverse activities and high quality bilberry extracts have been clinically studied in conditions like chronic venous insufficiency and diabetic retinopathy.Given the complexity of the industrial bilberries supply chain and thereof the high cost of their anthocyanins rich extracts, the dietary supplements market is facing a dramatic presence of adulterated extracts, either due to the use of anthocyanins from cheaper sources not related to bilberry or of chemical dyes.Although the current landscape is quite challenging, methods to detect the adulterations are at hand and need to be routinely implemented along the supply chain up to the finished product on the shelf.This review summarizes the market situation and gives a picture of the most recent analytical techniques available to the industry in order to spot these counterfeits and guarantee to the consumers a better quality and consistence of the products.