Regulation of lipid metabolism by strawberry extracts through AMP-activated protein kinase (AMPK) activation in HepG2 and 3T3-L1 cells

La regolazione del metabolismo lipidico è essenziale per il trattamento e la prevenzione delle malattie cardiovascolari, che risultano essere la principale causa di morte nel mondo. L’obiettivo principale del presente lavoro è stato quello di valutare gli effetti della fragole sull’AMP-activated protein kinase (AMPK), uno dei principali regolatori delle vie metaboliche coinvolte nella produzione di ATP e nel mantenimento dell’omeostasi nelle cellule di mammiferi e, quindi, nel metabolismo lipidico. Con questo scopo, due modelli cellulari sono stati utilizzati: human hepatocellular carcinoma cells (HepG2) e 3T3-L1 mouse embryo fibroblasts (3T3-L1), trattati con diversi estratti di fragola. Per la caratterizzazione del frutto, sono stati determinati i composti fenolici i flavonoidi totali e la vitamina C, così come la capacità antiossidante totale e l’attività di scavenger radicalico. È stata inoltre effettuata una identificazione e quantificazione all’HPLC degli antociani e dei folati. Per escludere il potenziale effetto citotossico degli estratti di fragola, si è valutata la vitalità cellulare, il tasso di apoptosi e di produzione di ROS intracellulari. In un secondo momento, sono stati confermati gli effetti ipolipemizzanti tramite la determinazione del contenuto di colesterolo totale, trigliceridi e colesterolo-LDL nei lisati cellulari, ed è stata anche determinata tramite western blot l’espressione di proteine legate alla cascata dell’AMPK. I risultati ottenuti dimostrano che gli estratti di fragola stimolano l'AMPK in maniera dipendente dall'LKB1, portando alla fosforilazione e alla conseguente inattivazione dell'acetil coenzyme A carbossilasi (ACC) e all'inibizione dell'idrossimetil-CoA reduttasi (HMGCR), rispettivamente i principali regolatori della sintesi degli acidi grassi e del colesterolo. Il trattamento con la fragola, inoltre, stimola il recettore LDL, la SIRT1 e la PGC1α, queste ultime due implicate nel bilancio ossido-riduttivo cellulare e nella biogenesi mitocondriale. Al contrario, la fragola riduce la sterol regulatory element-binding protein (SREBP) e la differenziazione dei pre-adipociti. Inoltre, gli estratti di fragola migliorano lo stato ossido-riduttivo delle cellule modulando la produzione di MDA, l’attività degli enzimi antiossidanti e la produzione di ROS. I risultati osservati vengono contrastati dal trattamento con il composto C, un inibitore farmacologico dell'AMPK, indicando come i numerosi effetti della fragola sul metabolismo lipidico siano mediati dall'attivazione di questa proteina.Regulation of lipid metabolism is essential for treatment and prevention of cardiovascular diseases, which are responsible for the most deaths worldwide. The main objective of the present work was to evaluate the in vitro effect of strawberry (cv. Romina) extracts on AMP-activated protein kinase (AMPK) and its possible repercussion on lipid metabolism. For such purpose two cell models were used: human hepatocellular carcinoma cells (HepG2) and 3T3-L1 mouse embryo fibroblasts (3T3-L1), which had been treated with different strawberry extracts. For strawberry characterization total phenolic compounds, flavonoids and vitamin C content, as well as, total antioxidant capacity and radical scavenging activity were determined. The identification and quantification of strawberry anthocyanins and folates by HPLC analysis were also conducted. In order to rule out the potential cytotoxic effects of strawberry extracts, cell viability, apoptosis rate and intracellular ROS production were performed. In a second step, the lipid-lowering effects of strawberry were confirmed through the determination of total cholesterol, triglycerides and LDL-cholesterol contents on cells lysates and the expression of proteins metabolically related to AMPK was determined by western blotting. The results demonstrated that strawberry extracts stimulated the LKB1/AMPK pathway leading to the phosphorylation and consequently inactivation of acetyl coenzyme A carboxylase (ACC) and inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the major regulators of fatty acids and cholesterol synthesis, respectively. Strawberry treatment also stimulated LDL receptor, SIRT1 and PGC1α; the last two are implicated in the cellular redox balance and the mitochondrial biogenesis. On the contrary, it decreased the sterol regulatory element-binding protein (SREBP) and the pre-adipocytes differentiation. Additionally, strawberry extracts improved the redox state of cells by modulating MDA production, antioxidant enzyme activity and ROS generation. The observed results were counteracted by treatment with compound C, an AMPK pharmacological inhibitor, suggesting that multiple effects of strawberry on lipid metabolism are mediated by the activation of this protein

Potential health benefit of garlic based on human intervention studies: a brief Overview

Garlic is a polyphenolic and organosulfur enriched nutraceutical spice consumed since ancient times. Garlic and its secondary metabolites have shown excellent health-promoting and disease-preventing effects on many human common diseases, such as cancer, cardiovascular and metabolic disorders, blood pressure, and diabetes, through its antioxidant, anti-inflammatory, and lipid-lowering properties, as demonstrated in several in vitro, in vivo, and clinical studies. The present review aims to provide a comprehensive overview on the consumption of garlic, garlic preparation, garlic extract, and garlic extract-derived bioactive constituents on oxidative stress, inflammation, cancer, cardiovascular and metabolic disorders, skin, bone, and other common diseases. Among the 83 human interventional trials considered, the consumption of garlic has been reported to modulate multiple biomarkers of different diseases; in addition, its combination with drugs or other food matrices has been shown to be safe and to prolong their therapeutic effects. The rapid metabolism and poor bioavailability that have limited the therapeutic use of garlic in the last years are also discussed

Nutrition and rheumatoid arthritis in the ‘Omics’ era

Modern high-throughput ‘omics’ science tools (including genomics, transcriptomics, proteomics, metabolomics and microbiomics) are currently being applied to nutritional sciences to unravel the fundamental processes of health effects ascribed to particular nutrients in humans and to contribute to more precise nutritional advice. Diet and food components are key environmental factors that interact with the genome, transcriptome, proteome, metabolome and the microbiota, and this life-long interplay defines health and diseases state of the individual. Rheumatoid arthritis (RA) is a chronic autoimmune disease featured by a systemic immune-inflammatory response, in genetically susceptible individuals exposed to environmental triggers, including diet. In recent years increasing evidences suggested that nutritional factors and gut microbiome have a central role in RA risk and progression. The aim of this review is to summarize the main and most recent applications of ‘omics’ technologies in human nutrition and in RA research, examining the possible influences of some nutrients and nutritional patterns on RA pathogenesis, following a nutrigenomics approach. The opportunities and challenges of novel ‘omics technologies’ in the exploration of new avenues in RA and nutritional research to prevent and manage RA will be also discussed

A pilot study of the photoprotective effects of strawberry-based cosmetic formulations on human dermal fibroblasts

Strawberry polyphenols have been extensively studied over the last two decades for their beneficial properties. Recently, their possible use in ameliorating skin conditions has also been proposed; however, their role in preventing UVA-induced damage in cosmetic formulation has not yet been investigated. Skin is constantly exposed to several environmental stressors, such as UVA radiation, that induce oxidative stress, inflammation and cell death via the production of reactive oxygen species (ROS). In the present study, we assessed the potential photoprotective capacity of different strawberry-based formulations, enriched with nanoparticles of Coenzyme Q10 and with sun protection factor 10 (SPF10), in human dermal fibroblasts (HuDe) exposed to UVA radiation. We confirmed that strawberries are a very rich source of polyphenols, anthocyanins and vitamins, and possess high total antioxidant capacity. We also showed that strawberry extracts (25 μg/mL-1 mg/mL) exert a noticeable photoprotection in HuDe, increasing cell viability in a dose-dependent way, and that these effects are potentiated by the presence of CoQ10red (100 μg/mL). We have demonstrated for the first time that the topical use of strawberry extract may provide good photoprotection, even if more in-depth studies are strongly encouraged in order to evaluate the cellular and molecular effects of strawberry protection