Synthesis and cannabinoid receptor activity of ketoalkenes from Echinacea pallida and nonnatural analogues

Cannabinoids: Revealing their complexity and role in central networks of fear and anxiety

The first aim of the present review is to provide an in-depth description of the cannabinoids and their known effects at various neuronal receptors. It reveals that cannabinoids are highly diverse, and recent work has highlighted that their effects on the central nervous system (CNS) are surprisingly more complex than previously recognized. Cannabinoid-sensitive receptors are widely distributed throughout the CNS where they act as primary modulators of neurotransmission. Secondly, we examine the role of cannabinoid receptors at key brain sites in the control of fear and anxiety. While our understanding of how cannabinoids specifically modulate these networks is mired by their complex interactions and diversity, a plausible framework(s) for their effects is proposed. Finally, we highlight some important knowledge gaps in our understanding of the mechanism(s) responsible for their effects on fear and anxiety in animal models and their use as therapeutic targets in humans. This is particularly important for our understanding of the phytocannabinoids used as novel clinical interventions.

Copper-Catalyzed Regioselective and Stereoselective Coupling of Grignard Reagents with Pent-1-en-4-yn-3-yl Benzoates: A Shortcut to ( Z) -1,5-Disubstituted Pent-3-en-1-ynes from Accessible Starting Materials

Copper-catalyzed coupling of Grignard reagents with pent-1-en-4-yn-3-yl benzoates occurs regioselectively at the terminal alkenyl carbon rather than the alkynyl site, leading to the stereoselective formation of unexpected ( Z) -1,5-disubstituted pent-3-en-1-ynes without generation of the initially expected alkenyl allene products. By using easily accessible starting materials, this reaction can provide direct access to thermodynamically unfavorable Z-configured enynes, which widely exist in many bioactive natural products, such as the anti-inflammatory components in henna.

Rabbit dietary supplementation with pale purple coneflower. 1. Effects on the reproductive performance and immune parameters of does

Echinacea pallida (EPAL), also known as pale purple coneflower, is a herbaceous flowering plant with immune-enhancement and antioxidative properties. The effect of EPAL on the reproductive performance, serum biochemistry and haematological parameters of rabbit does has been studied here. A total of 100, 21-week-old Grimaud rabbit does, were randomly assigned to two groups. One group was fed a basal diet supplemented with 3 g EPAL/kg diet (Echinacea group, E), while the other was fed the basal diet without the supplementation (control group, C). The reproductive performance of the does was not affected by the treatment (P>0.05). The haematological parameters of pregnant rabbits showed that there was no interaction between gestation day and treatment. The EPAL supplementation induced a reduction (-47.3%) in the basophil cell rate (0.55% and 0.29%, for the control and treatment groups, respectively; P=0.049). The gestation day significantly affected most of the haematological parameters (P<0.05). The white blood cell counts declined progressively after day 14. The mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, red cell distribution width, mean platelet volume and eosinophils increased steadily throughout the study, and reached a maximum value on day 28. The red blood cells, haemoglobin, haematocrit, mean corpuscular volume and neutrophils increased slightly up to day 14, and then subsequently decreased progressively until day 28. The lymphocytes and platelet distribution width decreased until day 14, and then increased to a maximum value on day 28. No significant effect of gestation day or treatment was observed on the blood serum chemistry. As far as the immune parameters are concerned, no significant differences were observed between groups, while a significant effect of gestation day was observed for lysozymes (6.02 v. 7.99 v. 1.91; for 0, 14 and 28 days, respectively; P=0.014). In conclusion, a lack of effect of EPAL has been observed. In fact, no impacts of EPAL have been observed on the reproductive or haematological parameters of the does. The effects of dietary supplementation with EPAL on the performances, bacterial community, blood parameters and immunity in growing rabbits are reported in the second part of this study.

Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development

The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2) which have been explored as potential therapeutic targets for drug discovery and development. Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ(9)-tetrahydrocannabinol mediates its action through CB1/CB2 receptors. However, these synthetic based Cannabis derived compounds are known to exert adverse psychiatric effect and have also been exploited for drug abuse. This encourages us to find out an alternative and safe drug with the least psychiatric adverse effects. In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems. Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative. The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics.

Enrichment of Echinacea angustifolia with Bauer alkylamide 11 and Bauer ketone 23 increased anti-inflammatory potential through interference with cox-2 enzyme activity

Bauer alkylamide 11 and Bauer ketone 23 were previously found to be partially responsible for Echinacea angustifolia anti-inflammatory properties. This study further tested their importance using the inhibition of prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production by RAW264.7 mouse macrophages in the absence and presence of lipopolysaccharide (LPS) and E. angustifolia extracts, phytochemical enriched fractions, or pure synthesized standards. Molecular targets were probed using microarray, qRT-PCR, Western blot, and enzyme assays. Fractions with these phytochemicals were more potent inhibitors of LPS-induced PGE(2) production than E. angustifolia extracts. Microarray did not detect changes in transcripts with phytochemical treatments; however, qRT-PCR showed a decrease in TNF-alpha and an increase of iNOS transcripts. LPS-induced COX-2 protein was increased by an E. angustifolia fraction containing Bauer ketone 23 and by pure phytochemical. COX-2 activity was decreased with all treatments. The phytochemical inhibition of PGE(2) production by Echinacea may be due to the direct targeting of COX-2 enzyme.

An examination of anthocyanins' and anthocyanidins' affinity for cannabinoid receptors

A growing body of evidence suggests that anthocyanins and anthocyanidins may possess analgesic properties in addition to neuroprotective and anti-inflammatory activities. These functionalities suggest a role for the cannabinoid receptor (CB) in mediating biological effects. Competitive radioligand binding assays identified cyanidin (K(i) = 16.2 microM) and delphinidin (K(i) = 21.3 microM) as ligands with moderate affinity to human CB1. For CB2, similar affinities were achieved by cyanidin (K(i) = 33.5 microM), delphinidin (K(i) = 34.3 microM), and peonidin (K(i) = 46.4 microM). Inhibition constants >50 microM were obtained for pelargonidin, malvidin, cyanidin-3,5-di-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, and cyanidin-3-O-rutinoside for both CB subtypes.

Falcarinol is a covalent cannabinoid CB1 receptor antagonist and induces pro-allergic effects in skin

The skin irritant polyyne falcarinol (panaxynol, carotatoxin) is found in carrots, parsley, celery, and in the medicinal plant Panax ginseng. In our ongoing search for new cannabinoid (CB) receptor ligands we have isolated falcarinol from the endemic Sardinian plant Seseli praecox. We show that falcarinol exhibits binding affinity to both human CB receptors but selectively alkylates the anandamide binding site in the CB(1) receptor (K(i)=594nM), acting as covalent inverse agonist in CB(1) receptor-transfected CHO cells. Given the inherent instability of purified falcarinol we repeatedly isolated this compound for biological characterization and one new polyyne was characterized. In human HaCaT keratinocytes falcarinol increased the expression of the pro-allergic chemokines IL-8 and CCL2/MCP-1 in a CB(1) receptor-dependent manner. Moreover, falcarinol inhibited the effects of anandamide on TNF-alpha stimulated keratinocytes. In vivo, falcarinol strongly aggravated histamine-induced oedema reactions in skin prick tests. Both effects were also obtained with the CB(1) receptor inverse agonist rimonabant, thus indicating the potential role of the CB(1) receptor in skin immunopharmacology. Our data suggest anti-allergic effects of anandamide and that falcarinol-associated dermatitis is due to antagonism of the CB(1) receptor in keratinocytes, leading to increased chemokine expression and aggravation of histamine action.