Association between non-tea flavonoid intake and risk of type 2 diabetes: the Australian diabetes, obesity and lifestyle study

Total flavonoids of Hippophae rhamnoides L. improves type 2 diabetes symptoms in rats through down-regulating of the DAG/PRKCA/MAPK10/p65/TNF-α signalling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Dry mature fruits of Hippophae rhamnoides L. (HRL), Elaeagnaceae, have traditional functions of invigorating spleen and improving spleen insufficiency. Traditional Chinese medicine (TCM) clinics have been proved that HRL is in favor of diabetes treatment. Modern pharmacological studies demonstrated that total flavones of Hippophae rhamnoides (TFH) are the main substance for HRL to develop anti-inflammation and anti-diabetes functions. However, chemical features, active ingredients and anti-diabetes pharmacological mechanism of HRL still remain unclear.

AIM OF THE STUDY

Key targets and metabolites in anti-type-II diabetes mellitus (T2DM) of TFH have been explored based on AGE-RAGE signaling pathway in diabetic complications. The anti-T2DM mechanism of TFH has been elaborated from comprehensive perspectives, including target prediction, metabolites, potential metabolic pathways, and so on.

MATERIALS AND METHODS

In this study, a qualitative test of chemical composition of HRL was carried out based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The anti-T2DM targets and pathways of HRL were predicted through network pharmacological approach. The T2DM rat model was induced by high-fat and high-glucose diet combined with streptozotocin (STZ). The T2DM model was evaluated through fasting blood glucose level, body weight, serum biochemical indicators, insulin levels and homeostatic model assessment of insulin resistance. The key metabolic pathways were screened through the correlation between metabolites and key targets. Finally, the quantitative analysis of key targets and metabolites was verified through experiments.

RESULTS

After TFH intervention, the fasting blood-glucose level of T2DM rats induced by high-fat and high-glucose diet combined with streptozotocin (STZ) was downregulated significantly, while body weight, serum liquid level, insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) were improved. According to ELISA, Western blotting (WB) and reverse transcriptase polymerase chain reaction (RT-PCR), TFH significantly downregulates expression levels of diglyceride (DAG)-activated protein kinase C (PRKCA), mitogen activated protein kinase 10 (MAPK10), human nuclear factor κB subunit p65 (NF-κB p65) and tumor necrosis factor-α (TNF-α) in pancreas of STZ-induced rats.

CONCLUSIONS

TFH downregulates expressions of PRKCA, MAPK10 and p65 TNF-α as well as level of the key metabolite DA in the DAG/PRKCA/MAPK10/TNF-α/p65 pathways, improves lipid metabolism disorder, inhibits inflammatory response and thereby relieves symptoms of T2DM.

Higher Habitual Dietary Intakes of Flavanols and Anthocyanins Differentially Associate with Lower Incidence of Ischemic Stroke Subtypes-A Follow-Up Analysis

BACKGROUND

We previously reported that habitual consumption of dietary flavanol oligomers + polymers and anthocyanins is associated with a lower risk of ischemic stroke. However, no studies have investigated their relationship with ischemic stroke subtypes.

OBJECTIVES

In this follow-up analysis, we aimed to examine the association of flavanol oligomers + polymers and anthocyanin intake with ischemic stroke subtypes, including the following: 1) large-artery atherosclerosis, 2) cardioembolism, 3) small-vessel occlusion, 4) other determined etiology, and 5) undetermined etiology.

METHODS

Participants (n = 55,094) from the Danish Diet, Cancer, and Health Study were followed up for <16 y for first-time ischemic stroke events, which were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Intakes of flavanol oligomers + polymers and anthocyanins were calculated from food frequency questionnaires using the Phenol-Explorer database, and their relationships with ischemic stroke subtypes were investigated using restricted cubic splines within Cox proportional hazards models. After multivariable adjustment, higher habitual intakes (quintile 5 compared with quintile 1) of flavanol oligomers + polymers and anthocyanins were associated with a lower risk of specific ischemic stroke subtypes, including large-artery atherosclerosis [flavanol oligomers + polymers, hazard ratio {HR} (95% confidence interval {CI}): 0.64 (0.47, 0.87)], cardioembolism [anthocyanins, HR (95% CI): 0.45 (0.25, 0.82)], and small-vessel occlusion [flavanol oligomers + polymers, HR (95% CI): 0.65 (0.54, 0.80); anthocyanins, HR (95% CI): 0.79 (0.64, 0.97)], but not stroke of other determined or undetermined etiology.

CONCLUSIONS

Higher habitual intakes of flavanols and anthocyanins are differentially associated with a lower risk of ischemic stroke from atherosclerosis and/or cardioembolism but not with other subtypes.

Performance of Urinary Phenyl-γ-Valerolactones as Biomarkers of Dietary Flavan-3-ol Exposure

BACKGROUND

Phenyl-γ-valerolactones (PVLs) have been identified as biomarkers of dietary flavan-3-ol exposure, although their utility requires further characterization.

OBJECTIVES

We investigated the performance of a range of PVLs as biomarkers indicative of flavan-3-ol intake.

METHODS

We report the results of 2 companion studies: a 5-way randomized crossover trial (RCT) and an observational cross-sectional study. In the RCT (World Health Organization, Universal Trial Number: U1111-1236-7988), 16 healthy participants consumed flavan-3-ol-rich interventions (of apple, cocoa, black tea, green tea, or water [control]) for 1 d each. First morning void samples and 24-h urine samples were collected with diet standardized throughout. For each participant, 1 intervention period was extended (to 2 d) to monitor PVL kinetics after repeat exposure. In the cross-sectional study, 86 healthy participants collected 24-h urine samples, and concurrent weighed food diaries from which flavan-3-ol consumption was estimated using Phenol-Explorer. A panel of 10 urinary PVLs was quantified using liquid chromatography tandem mass spectrometry.

RESULTS

In both studies, 2 urinary PVLs [5-(3'-hydroxyphenyl)-γ-valerolactone-4'-sulfate and putatively identified 5-(4'-hydroxyphenyl)-γ-valerolactone-3'-glucuronide] were the principal compounds excreted (>75%). In the RCT, the sum of these PVLs was significantly higher than the water (control) after each intervention; individually, there was a shift from sulfation toward glucuronidation as the total excretion of PVLs increased across the different interventions. In the extended RCT intervention period, no accumulation of these PVLs was observed after consecutive days of treatment, and after withdrawal of treatment on the third day, there was a return toward negligible PVL excretion. All results were consistent, whether compounds were measured in 24-h urine or first morning void samples. In the observational study, the sum of the principal PVLs correlated dose dependently (Rs = 0.37; P = 0.0004) with dietary flavan-3-ol intake, with similar associations for each individually.

CONCLUSIONS

Urinary 5-(3'-hydroxyphenyl)-γ-valerolactone-4'-sulfate and putatively identified 5-(4'-hydroxyphenyl)-γ-valerolactone-3'-glucuronide are recommended biomarkers for dietary flavan-3-ol exposure.

The Association between Coffee and Tea Consumption at Midlife and Risk of Dementia Later in Life: The HUNT Study

BACKGROUND

Studies exploring the possible protective effect of coffee and tea consumption on dementia have shown inconsistent results so far. We aimed to investigate whether consumption of tea and different types of coffee at midlife are associated with dementia later in life and whether sex or ApoE4 influence such association.

METHODS

We included 7381 participants from the Norwegian HUNT Study. Self-reported questionnaires assessed daily consumption of coffee and tea at baseline. After 22 years, individuals 70 years or older were screened for cognitive impairment.

RESULTS

General coffee consumption and tea consumption was not associated with dementia risk. Compared to daily consumption of 0-1 cups of coffee, daily consumption of ≥8 cups of boiled coffee was associated with increased dementia risk in women (OR: 1.83, 95% CI: 1.10-3.04, p-value for trend = 0.03) and daily consumption of 4-5 cups of other types of coffee was associated with a decrease in dementia risk in men (OR: 0.48, 95% CI: 0.32-0.72, p-value for trend = 0.05). Furthermore, the association between boiled coffee and increased dementia risk was only found in ApoE4 non-carriers. Differences by sex or ApoE4 carrier status were not supported by strong statistical evidence for interaction. Tea consumption was not associated with dementia risk.

CONCLUSION

type of coffee may play a role in the direction of the association between coffee-drinking habits and dementia later in life.

Separation of flavonoids with significant biological activity from Acacia mearnsii leaves

Acacia mearnsii leaves, which are a rich source of flavonoids, were used to separate and purify myricitrin (W3) and myricetin-3-O-glucoside (W1). Further, the antioxidant and hypoglycemic activities of the two purified flavonoids were evaluated. The flavonoids were separated using solvent partition, macroporous adsorbent resin column, and Sephadex column chromatography, and purified using preparative reverse-phase high-performance liquid chromatography (HPLC). The purified flavonoids were characterized using HPLC, mass spectrometry, and nuclear magnetic resonance methods. A high yield (7.3 mg g-1 of crude extract) of W3 was obtained, with a high purity of 98.4%. Furthermore, the purity of W1 was over 95%. W1 and W3 showed strong antioxidant activity and significantly inhibited α-glucosidase. W3 also demonstrated substantial α-amylase inhibitory capacity. This study indicated that A. mearnsii leaves, which are discarded in significant amounts, can be used as a source of myricitrin, thus providing more adequate material for the production of antioxidants and type II diabetes inhibitors. Hence, A. mearnsii leaves have the potential to create great market economic value and environmental benefits.

The protective effects of flavonoids and carotenoids against diabetic complications-A review of in vivo evidence

Diabetes mellitus is a chronic metabolic disorder caused either by inadequate insulin secretion, impaired insulin function, or both. Uncontrolled diabetes is characterized by hyperglycemia which over time leads to fatal damage to both macro-and microvascular systems, causing complications such as cardiovascular diseases, retinopathy and nephropathy. Diabetes management is conventionally delivered through modifications of diet and lifestyle and pharmacological treatment, using antidiabetic drugs, and ultimately insulin injections. However, the side effects and financial cost of medications often reduce patient compliance to treatment, negatively affecting their health outcomes. Natural phytochemicals from edible plants such as fruits and vegetables (F&V) and medicinal herbs have drawn a growing interest as potential therapeutic agents for treating diabetes and preventing the onset and progression of diabetic complications. Flavonoids, the most abundant polyphenols in the human diet, have shown antidiabetic effects in numerous in vitro and preclinical studies. The underlying mechanisms have been linked to their antioxidant, anti-inflammatory and immunomodulatory activities. Carotenoids, another major group of dietary phytochemicals, have also shown antidiabetic potential in recent in vitro and in vivo experimental models, possibly through a mechanism of action similar to that of flavonoids. However, scientific evidence on the efficacy of these phytochemicals in treating diabetes or preventing the onset and progression of its complications in clinical settings is scarce, which delays the translation of animal study evidence to human applications and also limits the knowledge on their modes of actions in diabetes management. This review is aimed to highlight the potential roles of flavonoids and carotenoids in preventing or ameliorating diabetes-related complications based on in vivo study evidence, i.e., an array of preclinical animal studies and human intervention trials. The current general consensus of the underlying mechanisms of action exerted by both groups of phytochemicals is that their anti-inflammatory action is key. However, other potential mechanisms of action are considered. In total, 50 in vivo studies were selected for a review after a comprehensive database search via PubMed and ScienceDirect from January 2002 to August 2022. The key words used for analysis are type-2 diabetes (T2DM), diabetic complications, flavonoids, carotenoids, antioxidant, anti-inflammatory, mechanisms of prevention and amelioration, animal studies and human interventions.

Metabolic outcomes in patients with type 2 diabetes mellitus after metabolic management center

The Chinese Medical Doctor Association has initiated metabolic management center (MMC) program for 6 years since 2016 nationwide. It is worth investigating the level of control metabolic outcomes in patients with type2 diabetes (T2DM) after MMC model in Yan'an, northwest China. Patients with T2DM was admitted to MMC in Yan'an University Affiliated Hospital from November 2018 to July 2021. They were asked to revisit hospital every 3 months. Blood glucose, blood pressure and blood lipids at baseline were compared to its counterparts after 1 year MMC management. Glycosylated hemoglobin and low density lipoprotein cholesterol (LDL-C) level in T2DM patients after 1 year management were lower than their baseline level (glycosylated hemoglobin 7.74 ± 1.94% vs 8.63 ± 2.26%, P < .001; LDL-C 1.81 ± 0.73mmol/L vs 2.18 ± 1.49mmol/L, P < .001). Mean HOMA-β increased after management (65.89 ± 90.81% vs 128.38 ± 293.93%, P < .05). After 1 year of management, patients in high school or above group achieved higher control rate of body mass index than those in middle school or below group (71.82% vs 28.18%, P = .043). high density lipoprotein cholesterol control rate was higher in high income group (42.86% vs 34.97%, 16.28%, P = .012), while LDL-C control rate was higher in low-income group (97.67% vs 78.57%, 84.51%, P = .018). fasting plasma glucose control rate in new diagnosis group was higher than that of the middle and long course groups (71.43% vs 52.38%, 42.44%, P = .002). The comprehensive control rate increased from 9.83% at baseline to 26.15% after 1 year MMC management. The metabolic outcomes and their control rate in T2DM patients were improved after 1 year MMC management. It indicated that patients may achieve more benefits with MMC management.