Improving endothelial health with food-derived H2S donors: an in vitro study with S-allyl cysteine and with a black-garlic extract enriched in sulfur-containing compounds.

A healthy vascular endothelium plays an essential role in modulating vascular tone by producing and releasing vasoactive factors such as nitric oxide (NO). Endothelial dysfunction (ED), the loss of the endothelium physiological functions, results in the inability to properly regulate vascular tone, leading to hypertension and other cardiovascular risk factors. Alongside NO, the gasotransmitter hydrogen sulfide (H2S) has emerged as a key molecule with vasodilatory and antioxidant activities. Since a reduction in H2S bioavailability is related to ED pathogenesis, natural H2S donors are very attractive. In particular, we focused on the sulfur-containing amino acid S-allyl cysteine (SAC), a bioactive metabolite, of which black garlic is particularly rich, with antioxidant activity and, among others, anti-diabetic and anti-hypertensive properties. In this study, we analyzed the protective effect of SAC against ED by evaluating reactive oxygen species level, H2S release, eNOS phosphorylation, and NO production (by fluorescence imaging and western blot analysis) in Bovine Aortic Endothelial cells (BAE-1). Furthermore, we chemically characterized a Black Garlic Extract (BGE) for its content in SAC and other sulfur-containing amino acids. BGE was used to carry out an analysis on H2S release on BAE-1 cells. Our results show that both SAC and BGE significantly increase H2S release. Moreover, SAC reduces ROS production and enhances eNOS phosphorylation and the consequent NO release in our cellular model. In this scenario, a natural extract enriched in SAC could represent a novel therapeutic approach to prevent the onset of ED-related diseases.

Plant-Derived Trans-ß-Caryophyllene Boosts Glucose Metabolism and ATP Synthesis in Skeletal Muscle Cells through Cannabinoid Type 2 Receptor Stimulation.

Skeletal muscle plays a pivotal role in whole-body glucose metabolism, accounting for the highest percentage of glucose uptake and utilization in healthy subjects. Impairment of these key functions occurs in several conditions including sedentary lifestyle and aging, driving toward hyperglycemia and metabolic chronic diseases. Therefore, strategies pointed to improve metabolic health by targeting skeletal muscle biochemical pathways are extremely attractive. Among them, we focused on the natural sesquiterpene and cannabinoid type 2 (CB2) receptor agonist Trans-ß-caryophyllene (BCP) by analyzing its role in enhancing glucose metabolism in skeletal muscle cells. Experiments were performed on C2C12 myotubes. CB2 receptor membrane localization in myotubes was assessed by immunofluorescence. Within glucose metabolism, we evaluated glucose uptake (by the fluorescent glucose analog 2-NBDG), key enzymes of both glycolytic and oxidative pathways (by spectrophotometric assays and metabolic radiolabeling) and ATP production (by chemiluminescence-based assays). In all experiments, CB2 receptor involvement was tested with the CB2 antagonists AM630 and SR144528. Our results show that in myotubes, BCP significantly enhances glucose uptake, glycolytic and oxidative pathways, and ATP synthesis through a CB2-dependent mechanism. Giving these outcomes, CB2 receptor stimulation by BCP could represent an appealing tool to improve skeletal muscle glucose metabolism, both in physiological and pathological conditions.

Protective Effects of (E)-ß-Caryophyllene (BCP) in Chronic Inflammation.

(E)-ß-caryophyllene (BCP) is a bicyclic sesquiterpene widely distributed in the plant kingdom, where it contributes a unique aroma to essential oils and has a pivotal role in the survival and evolution of higher plants. Recent studies provided evidence for protective roles of BCP in animal cells, highlighting its possible use as a novel therapeutic tool. Experimental results show the ability of BCP to reduce pro-inflammatory mediators such as tumor necrosis factor-alfa (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), thus ameliorating chronic pathologies characterized by inflammation and oxidative stress, in particular metabolic and neurological diseases. Through the binding to CB2 cannabinoid receptors and the interaction with members of the family of peroxisome proliferator-activated receptors (PPARs), BCP shows beneficial effects on obesity, non-alcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH) liver diseases, diabetes, cardiovascular diseases, pain and other nervous system disorders. This review describes the current knowledge on the biosynthesis and natural sources of BCP, and reviews its role and mechanisms of action in different inflammation-related metabolic and neurologic disorders.

PipeNig®-FL, a Fluid Extract of Black Pepper (Piper Nigrum L.) with a High Standardized Content of Trans-ß-Caryophyllene, Reduces Lipid Accumulation in 3T3-L1 Preadipocytes and Improves Glucose Uptake in C2C12 Myotubes.

Trans-ß-caryophyllene (BCP) is a natural sesquiterpene hydrocarbon with several important pharmacological activities, including antioxidant, anti-inflammatory, anticancer, and cardioprotective functions. These properties are mainly due to its selective interaction with the peripherally expressed cannabinoid receptor 2. In addition, BCP activates peroxisome proliferated activator receptors α and γ and inhibits the Toll-like receptor signaling pathway. Given the growing scientific interest in BCP, the aim of our study was to investigate the metabolic effects of a black pepper extract (PipeNig®-FL), containing a high standardized content of BCP. In particular our interest was focused on its potential activity on lipid accumulation and glucose uptake. The extract PipeNig®-FL was chemically characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame-ionization detection (GC-FID), confirming a high content (814 mg/g) of BCP. Experiments were performed on 3T3-L1 preadipocytes and on C2C12 myotubes. Lipid content following 3T3-L1 adipogenic differentiation was quantified with AdipoRed fluorescence staining. Glucose uptake and GLUT4 membrane translocation were studied in C2C12 myotubes with the fluorescent glucose analog 2-NBDG and by immunofluorescence analysis. Here we show that PipeNig®-FL reduces 3T3-L1 adipocyte differentiation and lipid accumulation. Moreover, acute exposure of C2C12 myotubes to PipeNig®-FL improves glucose uptake activity and GLUT4 migration. Taken together, these results reveal interesting and novel properties of BCP, suggesting potential applications in the prevention of lipid accumulation and in the improvement of glucose uptake.