Dietary strawberry powder reduces blood glucose concentrations in obese and lean C57BL/6 mice, and selectively lowers plasma C-reactive protein in lean mice

The roles of strawberry and honey phytochemicals on human health: A possible clue on the molecular mechanisms involved in the prevention of oxidative stress and inflammation

BACKGROUND

Oxidative stress and inflammation contribute to the etiopathogenesis of several human chronic diseases, such as cancer, diabetes, cardiovascular diseases and metabolic syndrome. Besides classic stimuli, such as reactive oxidant species, endotoxins (i.e., bacteria lipopolysaccharide), cytokines or carcinogens, oxidative stress and inflammation can be triggered by a poor diet and an excess of body fat and energy intake. Strawberry and honey are common rich sources of nutrients and bioactive compounds, widely studied for their roles exerted in health maintenance and disease prevention.

PURPOSE

This review aims to summarize and update the effects of strawberry and honey against oxidative stress and inflammation, with emphasis on metabolism and on the main molecular mechanisms involved in these effects.

METHODS

A wide range of literature, published in the last 10 years, elucidating the effects of strawberry and honey in preventing oxidative stress and inflammation both in vitro (whole matrix and digested fractions) and in vivo was collected from online electronic databases (PubMed, Scopus and Web of Science) and reviewed.

RESULTS

Strawberry and honey polyphenols may potentially prevent the chronic diseases related to oxidative stress and inflammation. Several in vitro and in vivo studies reported the effects of these foods in suppressing the oxidative stress, by decreasing ROS production and oxidative biomarkers, restoring the antioxidant enzyme activities, ameliorating the mitochondrial antioxidant status and functionality, among others, and the inflammatory process, by modulating the mediators of acute and chronic inflammation essential for the onset of several human diseases. These beneficial properties are mediated in part through their ability to target multiple signaling pathways, such as p38 MAPK, AMPK, PI3K/Akt, NF-κB and Nrf2.

CONCLUSIONS

Available scientific literature show that strawberry and honey may be effective in preventing oxidative stress and inflammation. The deep evaluation of the factors that affect their metabolism as well as the assessment of the main molecular mechanisms involved are of extreme importance for the possible therapeutic and preventive benefit against the most common human diseases. However, published literature is still scarce so that deeper studies should be performed in order to evaluate the bioavailability of these food matrices and their effects after digestion.

Ellagitannins from Rosa roxburghii suppress poly(I:C)-induced IL-8 production in human keratinocytes

The anti-inflammatory effects of a 50% aqueous extract of Rosa roxburghii fruit (RRFE) and two ellagitannins (strictinin and casuarictin) isolated from the RRFE were evaluated in a cell model of skin inflammation induced by self-RNA released from epidermal cells damaged by UV ray (UVR) irradiation. The RRFE inhibited interleukin-8 (IL-8) mRNA expression in normal human epidermal keratinocytes (NHEKs) stimulated with polyinosinic:polycytidylic acid (poly(I:C)), a ligand of toll-like receptor-3 (TLR-3). The plant-derived anti-inflammatory agents, dipotassium glycyrrhizinate (GK2) and allantoin, had no influence on the IL-8 expression. The purified compounds, strictinin and casuarictin, inhibited the IL-8 mRNA expression and IL-8 release induced in NHEKs by poly(I:C). These ellagitannins were thus found to be responsible for the biological activity exhibited by the RRFE. This study demonstrates that RRFE and isolated RRFE compounds show promise as ingredients for products formulated to improve skin disorders induced by UVR irradiation.

Berries as a Treatment for Obesity-Induced Inflammation: Evidence from Preclinical Models

Inflammation that accompanies obesity is associated with the infiltration of metabolically active tissues by inflammatory immune cells. This propagates a chronic low-grade inflammation associated with increased signaling of common inflammatory pathways such as NF-κB and Toll-like receptor 4 (TLR4). Obesity-associated inflammation is linked to an increased risk of chronic diseases, including type 2 diabetes, cardiovascular disease, and cancer. Preclinical rodent and cell culture studies provide robust evidence that berries and their bioactive components have beneficial effects not only on inflammation, but also on biomarkers of many of these chronic diseases. Berries contain an abundance of bioactive compounds that have been shown to inhibit inflammation and to reduce reactive oxygen species. Therefore, berries represent an intriguing possibility for the treatment of obesity-induced inflammation and associated comorbidities. This review summarizes the anti-inflammatory properties of blackberries, blueberries, strawberries, and raspberries. This review highlights the anti-inflammatory mechanisms of berries and their bioactive components that have been elucidated through the use of preclinical models. The primary mechanisms mediating the anti-inflammatory effects of berries include a reduction in NF-κB signaling that may be secondary to reduced oxidative stress, a down-regulation of TLR4 signaling, and an increase in Nrf2.

Berry Phenolic and Volatile Extracts Inhibit Pro-Inflammatory Cytokine Secretion in LPS-Stimulated RAW264.7 Cells through Suppression of NF-κB Signaling Pathway

Berries are a rich source of phytochemicals, especially phenolics well known for protective activity against many chronic diseases. Berries also contain a complex mixture of volatile compounds that are responsible for the unique aromas of berries. However, there is very limited information on the composition and potential health benefits of berry volatiles. In this study, we isolated phenolic and volatile fractions from six common berries and characterized them by HPLC/HPLC-MS and GC/GC-MS, respectively. Berry phenolic and volatile fractions were evaluated for an anti-inflammatory effect using lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells by measuring levels of pro-inflammatory cytokines and the nuclear factor-kappa B (NF-κB) signaling pathway. Results showed that LPS-induced excessive production of nitric oxide (NO), prostaglandin E₂ (PGE₂), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which were inhibited by berry phenolic and volatile extracts. Moreover, berry phenolic and volatile extracts reduced the nuclear translocation of NF-κB by blocking the phosphorylation of p65 and degradation of IκBα. These findings showed that berry volatiles from six berries had comparable anti-inflammatory effects to berry phenolics through the suppression of pro-inflammatory mediators and cytokines expression via NF-κB down-regulation, despite being present in the fruit at a lower concentration.

Select Polyphenol-Rich Berry Consumption to Defer or Deter Diabetes and Diabetes-Related Complications

Berries are considered "promising functional fruits" due to their distinct and ubiquitous therapeutic contents of anthocyanins, proanthocyanidins, phenolic acids, flavonoids, flavanols, alkaloids, polysaccharides, hydroxycinnamic, ellagic acid derivatives, and organic acids. These polyphenols are part of berries and the human diet, and evidence suggests that their intake is associated with a reduced risk or the reversal of metabolic pathophysiologies related to diabetes, obesity, oxidative stress, inflammation, and hypertension. This work reviewed and summarized both clinical and non-clinical findings that the consumption of berries, berry extracts, purified compounds, juices, jams, jellies, and other berry byproducts aided in the prevention and or otherwise management of type 2 diabetes mellitus (T2DM) and related complications. The integration of berries and berries-derived byproducts into high-carbohydrate (HCD) and high-fat (HFD) diets, also reversed/reduced the HCD/HFD-induced alterations in glucose metabolism-related pathways, and markers of oxidative stress, inflammation, and lipid oxidation in healthy/obese/diabetic subjects. The berry polyphenols also modulate the intestinal microflora ecology by opposing the diabetic and obesity rendered symbolic reduction of Bacteroidetes/Firmicutes ratio, intestinal mucosal barrier dysfunction-restoring bacteria, short-chain fatty acids, and organic acid producing microflora. All studies proposed a number of potential mechanisms of action of respective berry bioactive compounds, although further mechanistic and molecular studies are warranted. The metabolic profiling of each berry is also included to provide up-to-date information regarding the potential anti-oxidative/antidiabetic constituents of each berry.

A Review of the Potential Benefits of Plants Producing Berries in Skin Disorders

During the last 30 years, berries have gained great attention as functional food against several risk factors in chronic diseases. The number of related publications on Pubmed rose from 1000 items in 1990 to more than 11,000 in 2019. Despite the fact that a common and clear definition of "berries" is not shared among different scientific areas, the phytochemical pattern of these fruits is mainly characterized by anthocyanins, flavanols, flavonols, and tannins, which showed antioxidant and anti-inflammatory properties in humans. Skin insults, like wounds, UV rays, and excessive inflammatory responses, may lead to chronic dermatological disorders, conditions often characterized by long-term treatments. The application of berries for skin protection is sustained by long traditional use, but many observations still require a clear pharmacological validation. This review summarizes the scientific evidence, published on EMBASE, MEDLINE, and Scholar, to identify extraction methods, way of administration, dose, and mechanism of action of berries for potential dermatological treatments. Promising in vitro and in vivo evidence of Punica granatum L. and Vitis vinifera L. supports wound healing and photoprotection, while Schisandra chinensis (Turcz.) Baill. and Vaccinium spp. showed clear immunomodulatory effects. Oral or topical administrations of these berries justify the evaluation of new translational studies to validate their efficacy in humans.

Comparing the Potential of Near- and Mid-Infrared Spectroscopy in Determining the Freshness of Strawberry Powder from Freshly Available and Stored Strawberry

The quality of strawberry powder depends on the freshness of the fruit that produces the powder. Therefore, identifying whether the strawberry powder is made from freshly available, short-term stored, or long-term stored strawberries is important to provide consumers with quality-assured strawberry powder. Nevertheless, such identification is difficult by naked eyes, as the powder colours are very close. In this work, based on the measurement of near-infrared (NIR) spectroscopy and mid-infrared (MIR) spectra of strawberry powered, good classification results of 100.00% correct rates to distinguish whether the strawberry powder was made from freshly available or stored fruit was obtained. Furthermore, partial least squares regression and least squares support vector machines (LS-SVM) models were established based on NIR, MIR, and combination of NIR and MIR data with full variables or optimal variables of strawberry powder to predict the storage days of strawberries that produced the powder. Optimal variables were selected by successive projections algorithm (SPA), uninformation variable elimination, and competitive adaptive reweighted sampling, respectively. The best model was determined as the SPA-LS-SVM model based on MIR spectra, which had the residual prediction deviation (RPD) value of 11.198 and the absolute difference between root-mean-square error of calibration and prediction (AB_RMSE) value of 0.505. The results of this work confirmed the feasibility of using NIR and MIR spectroscopic techniques for rapid identification of strawberry powder made from freshly available and stored strawberry.

Impact of daily strawberry consumption on blood pressure and arterial stiffness in pre- and stage 1-hypertensive postmenopausal women: a randomized controlled trial

Growing evidence indicates that strawberries are cardioprotective. We conducted an eight-week randomized, double-blind, placebo-controlled, parallel arm clinical trial to investigate the effects of daily consumption of freeze-dried strawberry powder (FDSP) on blood pressure (BP) and arterial stiffness in pre- and stage 1-hypertensive postmenopausal women. Sixty postmenopausal women were randomly assigned to one of three groups: (1) control, (2) 25 g FDSP and (3) 50 g FDSP (n = 20 per group). Assessments of body weight, BP, arterial stiffness as measured by pulse wave velocity (PWV), and collection of blood samples for analyses of vasoactive and antioxidant molecules were performed at baseline, four and eight weeks. After eight weeks, systolic BP, as well as brachial- and femoral-ankle PWV were lower than baseline in the 25 g FDSP group (141 ± 3 to 135 ± 3 mmHg, P = 0.02; 15.5 ± 0.5 to 14.8 ± 0.4 m s^-1, P = 0.03, and 11.0 ± 0.2 to 10.4 ± 0.2 m s^-1, P = 0.02, respectively), whereas no statistically significant changes were observed in the control or 50 g FDSP groups. Plasma nitric oxide metabolite levels increased at four and eight weeks in the 50 g FDSP group compared to baseline (8.5 ± 1.2 to 13.6 ± 1.3 and 13.3 ± 1.5, respectively, P = 0.01), whereas no significant changes were observed in the control or 25 g FDSP groups. Serum levels of superoxide dismutase increased at four weeks returning to baseline levels at eight weeks in all three groups. Significant differences among groups were not detected for any of the parameters. Although BP and arterial stiffness improved in the 25 g FDSP group over time, a treatment effect was not observed. Thus, it would be premature to affirm that daily consumption of FDSP improves BP or vascular function in pre- and stage 1-hypertensive postmenopausal women. This trial was registered at as NCT02099578.

Circulating metabolites of strawberry mediate reductions in vascular inflammation and endothelial dysfunction in db/db mice

BACKGROUND

Cardiovascular disease is 2-4-fold more prevalent in patients with diabetes. Human studies support the cardiovascular benefits of strawberry consumption but the effects of strawberry on diabetic vasculature are unknown. We tested the hypothesis that dietary strawberry supplementation attenuates vascular inflammation and dysfunction in diabetic mice.

METHODS

Seven-week-old diabetic db/db mice that consumed standard diet (db/db) or diet supplemented with 2.35% freeze-dried strawberry (db/db + SB) for ten weeks were compared to non-diabetic control mice (db/+). Indices of vascular inflammation and dysfunction were measured. Endothelial cells (ECs) were isolated from the vasculature to determine the influence of strawberry on them. The effect of metabolites of strawberry on endothelial inflammation was determined by incubating mouse aortic ECs (MAECs) with ±5% serum, obtained from strawberry fed mice (metabolites serum) or standard diet fed mice (control serum) ± 25 mM glucose and 100 μM palmitate.

RESULTS

db/db mice exhibited an increased monocyte binding to vessel, elevated blood pressure, and reduced endothelial-dependent vasorelaxation compared with db/+ mice but each defect was attenuated in db/db + SB mice. The elevation of inflammatory molecules, NOX2 and inhibitor-κB kinase observed in ECs from db/db vs. db/+ mice was suppressed in db/db + SB mice. Glucose and palmitate increased endothelial inflammation in MAECs but were normalized by co-incubation with metabolites serum.

CONCLUSIONS

Dietary supplementation of strawberry attenuates indices of vascular inflammation and dysfunction in diabetic db/db mice. The effect of strawberry on vasculature is endothelial-dependent and possibly mediated through their circulating metabolites. Strawberry might complement conventional therapies to improve vascular complications in diabetics.

Lipid Accumulation in HepG2 Cells Is Attenuated by Strawberry Extract through AMPK Activation

Regulation of lipid metabolism is essential for treatment and prevention of several chronic diseases such as obesity, diabetes, and cardiovascular diseases, which are responsible for most deaths worldwide. It has been demonstrated that the AMP-activated protein kinase (AMPK) has a direct impact on lipid metabolism by modulating several downstream-signaling components. The main objective of the present work was to evaluate the in vitro effect of a methanolic strawberry extract on AMPK and its possible repercussion on lipid metabolism in human hepatocellular carcinoma cells (HepG2). For such purpose, the lipid profile and the expression of proteins metabolically related to AMPK were determined on cells lysates. The results demonstrated that strawberry methanolic extract decreased total cholesterol, low-density lipoprotein (LDL)-cholesterol, and triglycerides levels (up to 0.50-, 0.30-, and 0.40-fold, respectively) while it stimulated the p-AMPK/AMPK expression (up to 3.06-fold), compared to the control. AMPK stimulation led to the phosphorylation and consequent 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 entailed a 4.34-, 2.37-, and 2.47-fold overexpression of LDL receptor, sirtuin 1 (Sirt1), and the peroxisome proliferator activated receptor gamma coactivator 1-alpha (PGC-1α), respectively, compared to control. The observed results were counteracted by treatment with compound C, an AMPK pharmacological inhibitor, confirming that multiple effects of strawberries on lipid metabolism are mediated by the activation of this protein.

The Healthy Effects of Strawberry Polyphenols: Which Strategy behind Antioxidant Capacity?

Current evidence indicates that the consumption of strawberries, a natural source of a wide range of nutritive and bioactive compounds, is associated with the prevention and improvement of chronic-degenerative diseases. Studies involving cells and animals provide evidence on the anti-inflammatory, anticarcinogenic and antiproliferative activity of the strawberry. Epidemiological and clinical studies demonstrate that its acute consumption increases plasma antioxidant capacity, improves circulating inflammatory markers and ameliorates postprandial glycemic response. At the same time, a protracted intake reduces chronic inflammation and improves plasma lipid profile, supporting cardiovascular health, especially in individuals with increased risk for metabolic syndrome. To explain these beneficial effects, much attention has been paid in the past to the antioxidant properties of strawberry polyphenols. However, recent research has shown that their biological and functional activities are related not only to the antioxidant capacity but also to the modulation of many cellular pathways involved in metabolism, survival, proliferation, and antioxidant defenses. The aim of this review is to update and discuss the molecular and cellular mechanisms proposed in recent studies to elucidate the healthy effects of strawberry polyphenols against the most common chronic diseases, such as cancer, cardiovascular diseases, metabolic syndrome, and inflammation.

Freeze-dried strawberry and blueberry attenuates diet-induced obesity and insulin resistance in rats by inhibiting adipogenesis and lipogenesis

Freeze-dried strawberry/blueberry powder might be useful for treatment/prevention of obesity-related diseases as it improves weight, fat and glucose-related biomarkers.

Strawberry tannins inhibit IL-8 secretion in a cell model of gastric inflammation

In the present study we chemically profiled tannin-enriched extracts from strawberries and tested their biological properties in a cell model of gastric inflammation. The chemical and biological features of strawberry tannins after in vitro simulated gastric digestion were investigated as well. The anti-inflammatory activities of pure strawberry tannins were assayed to get mechanistic insights. Tannin-enriched extracts from strawberries inhibit IL-8 secretion in TNFα-treated human gastric epithelial cells by dampening the NF-κB signaling. In vitro simulated gastric digestion slightly affected the chemical composition and the biological properties of strawberry tannins. By using pure compounds, we found that casuarictin may act as a pure NF-κB inhibitor while agrimoniin inhibits IL-8 secretion also acting on other biological targets; in our system procyanidin B1 prevents the TNFα-induced effects without interfering with the NF-κB pathway. We conclude that strawberry tannins, even after in vitro simulated gastric digestion, exert anti-inflammatory activities at nutritionally relevant concentrations.

The Protective Effect of Antioxidants Consumption on Diabetes and Vascular Complications

Obesity and diabetes is generally accompanied by a chronic state of oxidative stress, disequilibrium in the redox balance, implicated in the development and progression of complications such as micro- and macro-angiopathies. Disorders in the inner layer of blood vessels, the endothelium, play an early and critical role in the development of these complications. Blunted endothelium-dependent relaxation and/or contractions are quietly associated to oxidative stress. Thus, preserving endothelial function and oxidative stress seems to be an optimization strategy in the prevention of vascular complications associated with diabetes. Diet is a major lifestyle factor that can greatly influence the incidence and the progression of type 2 diabetes and cardiovascular complications. The notion that foods not only provide basic nutrition but can also prevent diseases and ensure good health and longevity is now attained greater prominence. Some dietary and lifestyle modifications associated to antioxidative supply could be an effective prophylactic means to fight against oxidative stress in diabesity and complications. A significant benefit of phytochemicals (polyphenols in wine, grape, teas), vitamins (ascorbate, tocopherol), minerals (selenium, magnesium), and fruits and vegetables in foods is thought to be capable of scavenging free radicals, lowering the incidence of chronic diseases. In this review, we discuss the role of oxidative stress in diabetes and complications, highlight the endothelial dysfunction, and examine the impact of antioxidant foods, plants, fruits, and vegetables, currently used medication with antioxidant properties, in relation to the development and progression of diabetes and cardiovascular complications.

Promising Health Benefits of the Strawberry: A Focus on Clinical Studies

The potential health benefits associated with dietary intake of fruits have attracted increasing interest. Among berries, the strawberry is a rich source of several nutritive and non-nutritive bioactive compounds, which are implicated in various health-promoting and disease preventive effects. A plethora of studies have examined the benefits of strawberry consumption, such as prevention of inflammation disorders and oxidative stress, reduction of obesity related disorders and heart disease risk, and protection against various types of cancer. This review provides an overview of their nutritional and non-nutritional bioactive compounds and which factors affect their content in strawberries. In addition, the bioavailability and metabolism of major strawberry phytochemicals as well as their actions in combating many pathologies, including cancer, metabolic syndrome, cardiovascular disease, obesity, diabetes, neurodegeneration, along with microbial pathogenesis have been reviewed, with a particular attention to human studies.

Strawberry as a health promoter: an evidence based review

The health effects of strawberry bioactive compounds depend on the activation and modulation of several genetic and molecular mechanisms.

Berries: anti-inflammatory effects in humans

A sustained pro-inflammatory state is a major contributing factor in chronic disease development, progression, and complication, including the most commonly known diseases: cardiovascular disease, Alzheimer's, and type 2 diabetes. Fruits, such as berries, contain polyphenol compounds purported to have anti-inflammatory activity in humans. Among the most notable polyphenols in berries are anthocyanins, responsible for their distinctive colors of red, blue, and purple. Berries have been studied widely for their antioxidant properties; however, preclinical data suggest important effects on inflammatory pathways. Correspondingly, the effects of berries, including extracts and purified anthocyanins, have been the subject of a number of human trials. This review aims to evaluate the current state of the human science on berry (products) as a source of dietary polyphenols, particularly anthocyanins, to modulate inflammatory status. Identifying dietary strategies that manage the modern-day inflammatory burden has important implications for chronic disease risk reduction and informing dietary guidelines aimed at achieving and maintaining health.

Ellagic acid identified through metabolomic analysis is an active metabolite in strawberry ('Seolhyang') regulating lipopolysaccharide-induced inflammation

This study employed the metabolomic approach to identify the key constituent exerting anti-inflammatory activity in murine macrophage RAW 264.7 cells. Among the six different fractions (SF1-SF6) of the strawberry 'Seolhyang', SF4 showed more significant inhibition on iNOS expression than SF3, and ellagic acid was determined as the most significant different component between SF4 and SF3 using orthogonal partial least-squares discriminant analysis. Ellagic acid (0.3 and 1.0 μM) and SF4 (100 μg/mL) were found to regulate the same inflammatory mediators, inhibitory κB (IκB) and mitogen-activated protein kinases (MAPKs), which led to the reduction of tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and iNOS expressions. These results demonstrate that ellagic acid from strawberry 'Seolhyang' is the major component playing a crucial role in inflammation, suggesting the possible application of metabolomic analysis to determining the key ingredients having biological functions in the complicated food matrix.

Modulation of Strawberry/Cranberry Phenolic Compounds Glucuronidation by Co-Supplementation with Onion: Characterization of Phenolic Metabolites in Rat Plasma Using an Optimized μSPE-UHPLC-MS/MS Method

Plant phenolic compounds are suggested to exert pharmacological activities in regards to obesity and type-2 diabetes, but their mode of action is poorly understood due to a lack of information about their bioavailability. This work aimed to study the bioavailability of GlucoPhenol phenolic compounds, a strawberry-cranberry extracts blend, by characterizing plasma phenolic profile in obese rats. A comparison was performed by co-supplementation with an onion extract. Using an optimized μSPE-UHPLC-MS/MS method, 21 phenolic metabolites were characterized, mostly conjugated metabolites and microbial degradation products of the native phenolic compounds. Their kinetic profiles revealed either an intestinal or hepatic formation. Among identified metabolites, isorhamnetin glucuronide sulfate was found in greater amount in plasma. Three glucuronidated conjugates of strawberry-cranberry phenolic compounds, p-hydroxybenzoic acid glucuronide, catechins glucuronide, and methyl catechins glucuronide were found in higher quantities when GlucoPhenol was ingested together with onion extract (+252%, +279%, and +118% respectively), suggesting a possible induction of glucuronidation processes by quercetin. This work allowed the characterization of actual phenolic metabolites generated in vivo following a phenolic intake, the analysis of their kinetics and suggested a possible synergistic activity of phenolic compounds for improving bioavailability.

Effects of freeze-dried strawberry supplementation on metabolic biomarkers of atherosclerosis in subjects with type 2 diabetes: a randomized double-blind controlled trial

BACKGROUND

To our knowledge there has been no study investigating the impact of freeze-dried strawberry (FDS) supplementation on metabolic biomarkers of atherosclerosis in subjects with type 2 diabetes (T2D).

OBJECTIVE

This study was carried out to determine the effects of FDS supplementation on glycemic control, biomarkers of oxidative stress, inflammation and serum total antioxidant status in subjects with T2D compared to matched control subjects.

METHODS

Thirty-six subjects with T2D (23 females; mean body mass index 27.90 ± 3.7; mean age 51.57 ± 10 years) were randomly divided into two groups. The treatment group consumed 2 cups of FDS beverage (50 g of FDS is equivalent to 500 g of fresh strawberries) or macronutrient matched placebo powder with strawberry flavor daily for 6 weeks in a randomized double-blind controlled trial. Anthropometric measurements, dietary intakes, hemoglobin (Hb)A1c, antioxidant status, C-reactive protein and malondialdehyde (MDA) levels were assessed at baseline and 6 weeks post-intervention.

RESULTS

FDS supplementation significantly decreased C-reactive protein levels as a biomarker of inflammation (2.5 vs. 2.04 mg/l, p < 0.05) and lipid peroxidation in the form of MDA (3.36 vs. 2.7 nmol/ml, p < 0.05) at 6 weeks compared to the baseline. Moreover, supplementation led to a decreasing trend in HbA1c (-5.7%, p < 0.05) and significant increase in total antioxidant status in the FDS group (1.44 vs. 1.26 mmol/l, p < 0.01) compared to the placebo group. No significant changes were observed in serum glucose concentrations and anthropometric indices.

CONCLUSIONS

FDS improved glycemic control and antioxidant status, and reduced lipid peroxidation and inflammatory response in patients with T2D. Supplementation with freeze-dried berry products, as natural sources of antioxidants with low glycemic index, could be considered as an adjunctive therapy in ameliorating metabolic complications of T2D.

Inhibitory effect of a Cirsium setidens extract on hepatic fat accumulation in mice fed a high-fat diet via the induction of fatty acid β-oxidation

Cirsium setidens is a perennial medicinal herb that is rich in flavonoids. We investigated in this study the effect of a C. setidens ethanol extract (CSE) on the development of nonalcoholic fatty liver in mice fed a high-fat diet (HF). C57BL/6J mice were fed either a control diet (CON) or HF for 8 weeks, and then fed CON, HF, or HF with 100 mg/kg of BW CSE (HF+CSE) for an additional 7 weeks. The final body weight and adipose tissue weight of the mice in the HF+CSE group were significantly lower than those in the HF group. CSE also markedly diminished both the lipid droplets in the liver tissues and decreased the hepatic and serum triglycerides (TG) concentrations. CSE strongly increased the hepatic mRNA levels of carnitine palmitoyltransferase (CPT1) and medium-chain acyl-CoA dehydrogenase (MCAD), the fatty acid β-oxidation enzymes. The hepatic levels of phosphorylated-AMP-activated protein kinase (AMPK) were significantly higher in the HF+CSF group than in the HF group. These results suggest that CSE inhibited hepatic fat accumulation by up-regulating the expression of the fatty acid β-oxidation genes.