Effects of anthocyanidins on the conformational transition of Aβ(1-42) peptide: Insights from molecular docking and molecular dynamics simulations

Recent evidence from in vitro and in vivo studies has shown that anthocyanins and anthocyanidins can reduce and inhibit the amyloid beta (Aβ) species, one of the hallmarks of Alzheimer's disease (AD). However, their inhibition mechanisms on Aβ species at molecular details remain elusive. Therefore, in the present study, molecular modelling methods were employed to investigate their inhibitory mechanisms on Aβ(1-42) peptide. The results highlighted that anthocyanidins effectively inhibited the conformational transitions of helices into beta-sheet (β-sheet) conformation within Aβ(1-42) peptide by two different mechanisms: 1) the obstruction of two terminals from coming into contact due to the binding of anthocyanidins with residues of N- and second hydrophobic core (SHC)-C-terminals, and 2) the prevention of the folding process due to the binding of anthocyanidin with the central polar (Asp23 and Lys28) and native helix (Asp23, Lys28, and Leu34) residues. These new findings on the inhibition of β-sheet formation by targeting both N- and SHC-C-terminals, and the long-established target, D23-K28 salt bridge residues, not with the conventional central hydrophobic core (CHC) as reported in the literature, might aid in designing more potent inhibitors for AD treatment.

Association of dietary flavonoid intakes with prevalence of chronic respiratory diseases in adults

BACKGROUND AND AIMS

Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults.

METHODS AND RESULTS

The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 and 2017-2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75-0.98), 0.84 (0.72-0.97), 0.80(0.69-0.92), and 0.85(0.73-0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82-0.95], P < 0.01), and the largest effect was mainly from flavanones (weight = 0.41). In addition, we found that flavonoid intake was negatively linked with inflammatory markers, and systemic inflammation significantly mediated the associations of flavonoids with CRDs, with a mediation rate of 12.64% for CRP (P < 0.01).

CONCLUSION

Higher flavonoid intake was related with a lower prevalence of CRDs in adults, and this relationship may be mediated through systemic inflammation.

The relationship of dietary flavonoids and periodontitis in US population: a cross-sectional NHANES analysis

OBJECTIVES

We investigated the association between dietary flavonoids intake and periodontitis.

MATERIALS AND METHODS

This cross-sectional study analyzed data from the US National Health and Nutrition Examination Survey 2009-2010 on 3025 participants aged between 30 and 80 years who had full-mouth periodontal examination and dietary flavonoids intake data. This study used periodontal pocket depth (PPD) and clinical attachment loss (CAL) as periodontitis markers. Data were analyzed using multivariate linear regression.

RESULTS

After adjusting confounders, the middle tertile of total dietary flavonoids was associated with decreased mean PPD (0.06 mm, P = 0.016) and mean CAL (0.13 mm, P = 0.001) and the top tertile of total dietary flavonoids was significantly associated with decreases in mean PPD (0.05 mm, P = 0.029) and mean CAL (0.11 mm, P = 0.010). Both the middle and top tertiles of total flavonoids intake were significantly related with decreased mean CAL in females, those flossing 0 days/week, overweight and non-diabetic population but not in males, smokers, those flossing 1-6 days/week and diabetic population. Higher anthocyanidins, flavones and flavonols intake was significantly associated with decreased mean PPD and mean CAL while higher flavanones intake was only significantly associated with decreased mean CAL. Higher anthocyanidins intake was particularly related with greatest decreases in mean CAL (top tertile: 0.22 mm, middle tertile: 0.17 mm, both P < 0.010). However, no significant associations were found between isoflavones and flavan_3_ols intake and mean CAL.

CONCLUSIONS

Higher dietary flavonoids intake may be beneficial for periodontal health.

CLINICAL RELEVANCE

Additional anthocyanidins, flavanones, flavones and flavonols intake was associated with improved periodontal health.

Five similar anthocyanidin molecules display distinct disruptive effects and mechanisms of action on Aβ1-42 protofibril: A molecular dynamic simulation study

Alzheimer's disease (AD) is associated with the deposition of amyloid-β (Aβ) fibrillary aggregates. Disaggregation of Aβ fibrils is considered as one of the promising AD treatments. Recent experimental studies showed that anthocyanidins, one type of flavonoids abundant in fruits/vegetables, can disaggregate Aβ fibrillary aggregates. However, their relative disruptive capacities and underlying mechanisms are largely unknown. Herein, we investigated the detailed interactions between five most common anthocyanidins (cyanidin, aurantinidin, peonidin, delphinidin, and pelargonidin) and Aβ protofibril (an intermediate of Aβ fibrillization) by performing microsecond molecular dynamic simulations. We found that all five anthocyanidins can destroy F4-L34-V36 hydrophobic core and K28-A42 salt bridge, leading to Aβ protofibril destabilization. Aurantinidin exhibits the strongest damage to Aβ protofibril (with the most severe disruption on K28-A42 salt bridges), followed by cyanidin (with the most destructive effect on F4-L34-V36 core). Detailed analyses reveal that the protofibril-destruction capacities of anthocyanidins are subtly modulated by the interplay of anthocyanidin-protofibril hydrogen bonding, hydrophobic, aromatic stacking interactions, which are dictated by the number or location of hydroxyl/methyl groups of anthocyanidins. These findings provide important mechanistic insights into Aβ protofibril disaggregation by anthocyanidins, and suggest that aurantinidin/cyanidin may serve as promising starting-points for the development of new drug candidates against AD.

Whole-genome resequencing and transcriptome analyses of four generation mutants to reveal spur-type and skin-color related genes in apple (Malus domestica Borkh. Cv. Red delicious)

BACKGROUND

Bud sport is a kind of somatic mutation that usually occurred in apple. 'Red Delicious' is considered to be a special plant material of bud sport, whereas the genetic basis of plant mutants is still unknown. In this study, we used whole-genome resequencing and transcriptome sequencing to identify genes related to spur-type and skin-color in the 'Red Delicious' (G0) and its four generation mutants including 'Starking Red' (G1), 'Starkrimson' (G2), 'Campbell Redchief' (G3) and 'Vallee Spur' (G4).

RESULTS

The number of single nucleotide polymorphisms (SNPs), insertions and deletions (InDels) and structural variations (SVs) were decreased in four generation mutants compared to G0, and the number of unique SNPs and InDels were over 9-fold and 4-fold higher in G1 versus (vs.) G2 and G2 vs. G3, respectively. Chromosomes 2, 5, 11 and 15 carried the most SNPs, InDels and SVs, while chromosomes 1 and 6 carried the least. Meanwhile, we identified 4,356 variation genes by whole-genome resequencing and transcriptome, and obtained 13 and 16 differentially expressed genes (DEGs) related to spur-type and skin-color by gene expression levels. Among them, DELLA and 4CL7 were the potential genes that regulate the difference of spur-type and skin-color characters, respectively.

CONCLUSIONS

Our study identified potential genes associated with spur-type and skin-color differences in 'Red Delicious' and its four generation mutants, which provides a theoretical foundation for the mechanism of the apple bud sport.

Heavy metal levels and flavonoid intakes are associated with chronic obstructive pulmonary disease: an NHANES analysis (2007-2010 to 2017-2018)

BACKGROUND

The association between exposure to environmental metals and chronic obstructive pulmonary disease (COPD) is preventing chronic lung diseases. However, little is currently known about the interaction between heavy metals and flavonoids in relation to the risk of COPD. This study aims to bridge this knowledge gap by leveraging The National Health and Nutrition Examination Survey (NHANES) database to evaluate thecorrelation between blood levels of heavy metals (cadmium, lead, mercury) and the intake of various flavonoid compounds (isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, flavonols, total flavonoids). Additionally, appropriate dietary recommendations are provided based on the study findings.

MATERIALS AND METHODS

Cross-sectional analysis was conducted using the 2007-2010 and 2017-2018 NHANES data. Specialized weighted complex survey design analysis software was used for data analysis. Multivariate logistic regression models and restricted cubic splines (RCS) were used to evaluate the relationship between blood heavy metal levels, flavonoids intake, and COPD incidence in all participants, and to explore the effect of different levels of flavonoids intake on COPD caused by heavy metal exposure.

RESULTS

A total of 7,265 adults aged ≥ 40 years were analyzed. Higher levels of blood cadmium (Cd), blood lead and Anthocyanidin (AC) intake were independently associated with an increased risk of COPD (Cd highest quantile vs. lowest: OR = 1.73, 95% CI, 1.25-2.3; Lead highest quantile vs. lowest quantile: OR = 1.44, 95% CI, 1.11-1.86; AC highest quantile vs. lowest: OR = 0.73, 95% CI, 0.54-0.99). When AC intake exceeded 11.56 mg/d, the effect of Cd exposure on COPD incidence decreased by 27%, and this finding was more significant in smokers.

CONCLUSION

Higher levels of Cd (≥ 0.45ug/L) and lead (≥ 0.172 ug/L) were positively correlated with the risk of COPD among participants aged 40 years and above, while AC intake (≥ 11.56 mg/d) could reduce the risk related to blood Cd.

Association between dietary anthocyanidins intake and depression among US adults: a cross-sectional study (NHANES, 2007-2010 and 2017-2018)

BACKGROUND

Anthocyanidins encompass a diverse array of compounds that possess notable anti-inflammatory and antioxidant properties with pharmacological activity. However, the correlation between the consumption of anthocyanidins through diet and its impact on depression has yet to be investigated.

METHODS

This study utilized the Food and Nutrient Database for Dietary Studies (FNDDS) expanded flavonoid intake database, as well as data from the National Health and Nutrition Examination Survey (NHANES) from the years 2007 to 2010 and 2017 to 2018. The analysis of the collected data was conducted in R, following the guidelines outlined in the official NHANES user guide "Stratified Multi-stage Probability Sampling". Three different models were developed using logistic regression to assess the protective effects of T3 (representing the highest intake of anthocyanidins) against depression. Additionally, the study aimed to investigate whether there existed a non-linear relationship between the dietary intake of anthocyanidins and the prevalence of depression by employing restricted cubic spline (RCS) analysis.

RESULTS

A total of 6,845 eligible participants were included in this cross-sectional study, with their data appropriately weighted to represent a population of 89.8 million people in the United States of America. The results demonstrated that individuals diagnosed with depression had a significantly lower dietary intake of anthocyanidins compared to those without depression (P < 0.0001). Moreover, significant differences were observed among different participant groups regarding socioeconomic status and the presence of chronic physical illnesses (such as hypertension, glucose status, and chronic kidney disease risk, etc.) (P < 0.05). After adjustment for covariates, participants with the highest intake of anthocyanins (T3) demonstrated a significantly reduced risk of depression [OR_T3 = 0.67, 95%CI: (0.48-0.95), (P_trend= 0.02]. Furthermore, the RCS analysis revealed a significant linear relationship between dietary anthocyanidin intake and depression (P for non-linear = 0.5876).

CONCLUSION

Our findings reveal a negative association between dietary anthocyanidin intake and depression.

Coordinated encapsulation by β-cyclodextrin and chitosan derivatives improves the stability of anthocyanins

To improve the stability of anthocyanins (ACNs), ACNs were loaded into dual-encapsulated nanocomposite particles by self-assembly using β-cyclodextrin (β-CD) and two different water-soluble chitosan derivatives, namely, chitosan hydrochloride (CHC) and carboxymethyl chitosan (CMC). The ACN-loaded β-CD-CHC/CMC nanocomplexes with small diameters (333.86 nm) and had a desirable zeta potential (+45.97 mV). Transmission electron microscopy (TEM) showed that the ACN-loaded β-CD-CHC/CMC nanocomplexes had a spherical structure. Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (¹H NMR) and X-ray diffraction (XRD) confirmed that the ACNs in the dual nanocomplexes were encapsulated in the cavity of the β-CD and that the CHC/CMC covered the outer layer of β-CD through noncovalent hydrogen bonding. The ACNs from the dual-encapsulated nanocomplexes improved stability of ACNs under adverse environmental conditions or in a simulated gastrointestinal environment. Further, the nanocomplexes exhibited good storage stability and thermal stability over a wide pH range when added into simulated electrolyte drinks (pH = 3.5) and milk tea (pH = 6.8). This study provides a new option for the preparation of stable ACNs nanocomplexes and expands the applications for ACNs in functional foods.

Identification and characterisation of MdUGT78T2 as a galactosyltransferase with dual activity on flavonol and anthocyanidin substrates in red-skinned apple fruit (Malus domestica L.)

Anthocyanidin and flavonol glycosides have been linked to the health-promoting effects associated with apple consumption. However, very few enzymes involved in flavonoid glycosylation have been characterised to date. Here, we present the identification and phylogenetic analysis of 234 putative glycosyltransferases involved in flavonoid biosynthesis, and detail the biochemical and structural characterisation of MdUGT78T2 as a strict galactosyltransferase involved in the formation of quercetin-3-O-galactoside and cyanidin-3-O-galactoside, the major glycoconjugates of flavonoids in apple. The enzyme is also active on other flavonoids but with a lower catalytic efficiency. Our data, complemented with gene expression analysis suggest that MdUGT78T2 synthesises the glycoconjugates at both the early and late stages of fruit development. This newly discovered type of catalytic activity can potentially be exploited for in vitro modification of flavonoids to increase their stability in food products and to modify apple fruits and other commercial crops through breeding approaches to enhance their health benefits.

Resonance structure contributions, flexibility, and frontier molecular orbitals (HOMO-LUMO) of pelargonidin, cyanidin, and delphinidin throughout the conformational space: application to antioxidant and antimutagenic activities

This research refers to the study and understanding of the conformational space of the positive-charged anthocyanidin structures in relation with the known chemical reactivities and bioactivities of these compounds. Therefore, the planar (P) and nonplanar (Z) conformers of the three hydroxylated anthocyanidins pelargonidin, cyanidin, and delphinidin were analyzed throughout the conformational space at the B3LYP/6-311 ++ G** level of theory. The outcome displayed eleven new conformers for pelargonidin, fifty-four for cyanidin, and thirty-one for delphinidin. Positive-charged quinoidal structures showed a significant statistical weight in the conformational space, thus coexisting simultaneously with other resonance structures, such that under certain reaction conditions, the anthocyanidins behave as positive-charged quinoidal structures instead of oxonium salts. The calculations of the permanent dipole moment and the polarizability showed relationships with the quantity and arrangement of hydroxyls in the structure. In addition, theoretical calculations were used to analyze the frontier molecular orbitals (HOMO-LUMO) of the three anthocyanidins. The novel conception of this work lies in the fact that dipole moment, polarizability, and HOMO-LUMO values were related to the reactivity/bioactivity of these three anthocyanidins. HOMO-LUMO energy gaps were useful to explain the antioxidant activity, while the percent atom contributions to HOMO were appropriate to demonstrate the antimutagenic activity as enzyme inhibitors, as well as the steric and electrostatic requirements to form the pharmacophore. Delphinidin was the strongest antioxidant anthocyanidin, and pelargonidin the best anthocyanidin with antimutagenic activity.

Biochemical changes and quality characterization of cold-stored 'Sahebi' grape in response to postharvest application of GABA

In this study, the effect of γ-aminobutyric acid (GABA) at 0 (control), 20 and 40 mM on maintaining postharvest quality, chilling tolerance and fungal decay of 'Sahebi' grapevine (Vitis vinifera L.) was investigated during 60 days storage at 1 °C. GABA-treated fruits especially at 40 mM showed less weight loss (35%), rachis browning (30%) and decay incident (63%) compared to the control. GABA-induced abscisic acid was linked to lower membrane electrolyte leakage (13%) in treated grapes. Moreover, at the end of 60 days, GABA treatment at 40 mM resulted in higher activities of antioxidant enzymes including superoxide dismutase (50%), catalase (35%), guaiacol peroxidase (65%), and ascorbate peroxidase (47%) and lower malondialdehyde (21%) compared to control samples. The highest soluble sugars and organic acids were related to 40 mM GABA-treated grape clusters. Phenolic compounds (phenolic acids, stilbenes, flavonoids and anthocyanidins) and antioxidant capacity increased in 40 mM GABA-treated grape due to lower polyphenol oxidase activity. Therefore, GABA is recommended for maintaining internal quality and reduction in fungal decay and chilling injury of grapes during postharvest storage.

Flavonoids as an effective sensitizer for anti-cancer therapy: insights into multi-faceted mechanisms and applicability towards individualized patient profiles

Cost-efficacy of currently applied treatments is an issue in overall cancer management challenging healthcare and causing tremendous economic burden to societies around the world. Consequently, complex treatment models presenting concepts of predictive diagnostics followed by targeted prevention and treatments tailored to the personal patient profiles earn global appreciation as benefiting the patient, healthcare economy, and the society at large. In this context, application of flavonoids as a spectrum of compounds and their nano-technologically created derivatives is extensively under consideration, due to their multi-faceted anti-cancer effects applicable to the overall cost-effective cancer management, primary, secondary, and even tertiary prevention. This article analyzes most recently updated data focused on the potent capacity of flavonoids to promote anti-cancer therapeutic effects and interprets all the collected research achievements in the frame-work of predictive, preventive, and personalized (3P) medicine. Main pillars considered are: - Predictable anti-neoplastic, immune-modulating, drug-sensitizing effects; - Targeted molecular pathways to improve therapeutic outcomes by increasing sensitivity of cancer cells and reversing their resistance towards currently applied therapeutic modalities.

Functional characterization of two chalcone isomerase (CHI) revealing their responsibility for anthocyanins accumulation in mulberry

Mulberry (Morus sp., Moraceae) is an important economic crop plant and mulberry fruits are rich in anthocyanidins. Chalcone isomerase (CHI) catalyzes the conversion of chalcones to flavanones providing precursors for biosynthesis of anthocyanidins. In this study, bona fide CHIs were cloned and characterized from different Morus species with differently colored fruits (Morus multicaulis, Mm and Morus alba variety LvShenZi, LSZ). Enzymatic assay of MmCHI1 and MmCHI2 showed that they can utilize naringenin chalcone as substrate. The catalytic efficiency of MmCHI2 and LSZCHI2 are approximately 200 and 120-fold greater than that of MmCHI1 respectively. Phylogenetic analysis showed the two mulberry CHIs belonged to different sub-clade of Type I CHI1 named type IA (CHI2) and type IB (CHI1). Type IB CHIs are mulberry specific. MmCHI1 and MmCHI2 had similar expression profiles and showed preferred expression in fruits. In addition, both mulberry CHI1 and CHI2 played roles in the response to excess zinc stress and sclerotiniose pathogen infection. Both MmCHI1 and MmCHI2 expression levels showed positive close relationship with anthocyanins content during fruit ripening process. The co-expression of MmCHI1 and MmCHI2 was observed during fruit ripening process and in transgenic mulberry. VIGS (virus induced gene silence) targeting on MmCHI1 and MmCHI2 showed significant down-regulation of MmCHI2 instead of MmCHI1 would result in significant (about 50%) decrease in anthocyanins content. MmCHI2 is the dominant CHI for anthocyanins accumulation in mulberry. The results presented in this work provided insight on bona fide CHIs in mulberry and reveal their roles in anthocyanins accumulation.

Dietary flavonoid intake and risk of esophageal squamous cell carcinoma: A population-based case-control study

OBJECTIVES

The aim of this population-based case-control study was to investigate the association between dietary consumption of the total flavonoids, subclasses, and specific flavonoids and the risk of esophageal squamous cell carcinoma (ESCC) among adults in a high-risk area of China.

METHODS

We recruited 820 ESCC participants and 863 control participants from Yanting County. Dietary flavonoids were assessed using a validated 76-item food frequency questionnaire. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic regression after considering potential confounders.

RESULTS

Comparing the highest and lowest intake quartiles, we observed a negative association of ESCC risk with consumption of isoflavones (OR = 0.34, 95% CI = 0.23-0.50, P for trend < 0.001), daidzein (OR = 0.31, 95% CI = 0.21-0.45, P for trend < 0.001), genistein (OR = 0.34, 95% CI = 0.23-0.50, P for trend < 0.001), and glycitein (OR = 0.32, 95% CI = 0.22-0.48, P for trend < 0.001) after adjustment for potential confounders. A more pronounced negative association was observed when comparing the third quartile, rather than the fourth, with the lowest quartile for consumption of anthocyanidins (OR = 0.58, 95% CI = 0.42-0.80, P for trend = 0.004), delphinidin (OR = 0.57, 95% CI = 0.41-0.78, P for trend = 0.004), and cyanidin (OR = 0.48, 95% CI = 0.35-0.66, P for trend = 0.003) after considering potential confounders. Consumption of total flavonoids, flavones, flavonols, and six other specific flavonoids (quercetin, myricetin, kaempferol, luteolin, apigenin, and peonidin) was not associated with ESCC risk.

CONCLUSIONS

The results suggest that increased dietary intake of isoflavones and moderate consumption of anthocyanidins were associated with a decreased risk of ESCC. Future nutritional guidelines may emphasize foods or supplements rich in specific isoflavones and anthocyanidins for ESCC chemoprevention.

Transcriptome analysis reveals the mechanism of anthocyanidins biosynthesis during grains development in purple corn (Zea mays L.)

Anthocyanidins are important pigments that cause plant tissues to develop colors. They have attracted much attention due to their crucial regulatory roles in plant growth as well as their health benefits. In order to reveal the molecular mechanism of anthocyanidin synthesis and regulation in purple corn (Zea mays L.) in this study, purple corn 963 was used to compare differences in gene expression during three stages of grain development by transcriptome analysis. A total of 17,168 differentially expressed genes (DEGs) (7564 up-regulated and 9604 down-regulated DGEs) were identified. The DEGs were significantly enriched in "Phenylpropanoid biosynthesis", "Biosynthesis of secondary metabolites", and "Plant hormone signal transduction". In addition, 72 % of the structural genes that regulate anthocyanidin synthesis were up-regulated, and the transcription factors related to the accumulation of anthocyanidins were enriched during grain development. Moreover, the differential expression of phytohormone genes might also be an important factor in anthocyanidin accumulation. Transcriptomic analysis presents a molecular basis for the study of grain color changes in the three stages of grain development, and provides information for further research on the mechanism of anthocyanidin synthesis.

The effects of bioactive compounds from blueberry and blackcurrant powders on the inhibitory activities of oat bran pastes against α-amylase and α-glucosidase linked to type 2 diabetes

The α-amylase and α-glucosidase inhibitory activities by extracts of oat bran, blueberry and blackcurrant powders, as well as oat bran pastes supplemented 25% of blueberry and blackcurrant powder, were studied by measuring their half inhibitory (IC50) concentrations. Addition of blueberry or blackcurrant powder into oat bran paste increased α-amylase and α-glucosidase inhibitory activities with a decrease in IC50 values. The main anthocyanidin content was measured by pH differential method and the potential inhibitory mechanisms of these extracts were also investigated by detailed inhibition kinetics and docking simulations. The results showed that: (1) cyanidin and delphinidin were the main anthocyanidin profiles in extracts; (2) only blackcurrant powder was a competitive inhibitor, while other extracts were all mixed-type inhibitors against α-amylase; (3) both blueberry- and blackcurrant-enriched pastes were competitive inhibitors, while other extracts were all mixed-type inhibitors towards α-glucosidase; (4) the α-amylase and α-glucosidase inhibitory activities by extracts were potentially driven by hydrogen bonding, cyanidin-3-glucoside and delphinidin-3-glucoside had stronger binding affinity compared to malvidin-3-glucoside and cyanidin-3-rutinside. This study suggested supplementary of blueberry and blackcurrant with oat bran might be a potential source of bioactive products for antidiabetic activity.

Not-from-concentrate pilot plant 'Wonderful' cultivar pomegranate juice changes: Quality

Colorful fruits conveying astringent beverages providing well documented health-benefits may present clarification, turbidity and sedimentation problems. Hydraulic pressing whole 'Wonderful' pomegranates and ultrafiltration followed by high temperature short-time pasteurization was used to mimic the dominant U.S. commercial juicing protocol, delivering not-from-concentrate juices, stored at 4 and 25 °C for 3 months. A goal was to avoid expensive and complicated clarification and fining steps. Data were subjected to an analysis of variance and principal components analysis. Changes in quality attributes, organic acids and anthocyanidins are presented. Hydraulic pressing, ultrafiltration and initial pasteurization had minor effects on color parameters, organic acids and anthocyanidins. There were no significant temperature, time or factorial effects for all color parameters during storage of the not-from-concentrate pasteurized juices. However, there were significant time- and temperature-effect decreases in organic acids and anthocyanidins. This is the first report on quality attributes in ultrafiltered, pasteurized and stored not-from-concentrate 'Wonderful' pomegranate juice.

Inverse association of total polyphenols and flavonoids intake and the intake from fruits with the risk of gestational diabetes mellitus: A prospective cohort study

BACKGROUND & AIMS

Emerging evidence has shown the inverse association between dietary polyphenols intake and type 2 diabetes mellitus risk, however, few studies focus on the prospective effects of polyphenols on gestational diabetes mellitus (GDM). Thus, the aim was to evaluate whether higher polyphenols intake and the intake from fruits and vegetables was correlated to a lower risk of GDM.

METHODS

Dietary intake of polyphenols of women with a singleton pregnancy and without any history of diabetes were obtained by a validated food frequency questionnaire from Tongji Maternal and Child Health Cohort study. Oral glucose tolerance tests were conducted at 24-28 weeks to screen for GDM. Logistic regression models were used to evaluate the association between dietary intake of polyphenols, and the results were presented as odds ratios (ORs) with 95% confidence interval (CIs). Generalized linear models were adopted to determine the association of polyphenols intake with blood glucose concentrations, and the results were presented as coefficients (β) with 95% CIs.

RESULTS

185 (8.3%) of 2231 pregnant women were diagnosed with GDM. The intake of total polyphenols was 319.9 (217.8-427.0) mg/d, and the intake from fruits and vegetables was 201.6 (115.3-281.8) mg/d and 63.2 (41.1-92.7) mg/d, respectively. Compared with the lowest quartile, the adjusted ORs (95% CIs) of GDM risk for women with the highest quartile of total polyphenols and flavonoids intake was 0.55 (0.30, 0.99), and 0.57 (0.32, 0.99). The adjusted ORs (95% CIs) of GDM risk was 0.55 0.51 (0.30, 0.87) (P_{for trend} = 0.017) for polyphenols from fruits, 0.58 (0.34, 0.99) (P_{for trend} = 0.038) for flavonoids from fruits, and 0.62 (0.38, 1.00) (P_{for trend} = 0.065) for anthocyanidins from fruits comparing the highest versus lowest quartile. In addition, each 100 mg increase of total polyphenols and polyphenols from fruits was associated with 0.054 (0.008, 0.096) (P = 0.021) and 0.061 (0.012, 0.109) (P = 0.015) decrease in 2-h post-load blood glucose. No significant association was found between total polyphenols from vegetables intake and the risk of GDM.

CONCLUSIONS

Higher dietary intake of total polyphenols and flavonoids and the intake from fruits was associated with lower GDM risk. This study was registered at clinicaltrials.gov as NCT03099837.

Chemical compositions and α-glucosidase inhibitory effects of anthocyanidins from blueberry, blackcurrant and blue honeysuckle fruits

The chemical compositions and α-glucosidase inhibitory activities of anthocyanins extracted from blueberry, blackcurrant and blue honeysuckle fruits and their acid hydrolysates (anthocyanidins) were analysed. Those anthocyanins were glycosidic anthocyanins that converted to anthocyanidins during acid hydrolysis, leading to increases in their α-glucosidase inhibitory activities (expressed as IC₅₀ values) from 0.232, 0.152 and 0.188 to 0.113 to 0.005 and 0.025 mg/mL. The potential inhibitory mechanism of these anthocyanidins was then investigated through inhibition kinetics, fluorescence quenching and docking simulations. The results showed the following: 1) all anthocyanidins were mixed-type inhibitors of α-glucosidase and they bind more tightly to free α-glucosidase as compared to the α-glucosidase-substrate complex; 2) anthocyanidin inhibition of α-glucosidase was a static procedure, presumably driven by hydrophobic associations and hydrogen bonding; and 3) all anthocyanidins were inserted into the active site of α-glucosidase and avoided the entrance of p-nitrophenyl-a-D-glucopyranoside. This study is valuable for anthocyanidins as potential α-glucosidase inhibitors.

Effects of malvidin, cyanidin and delphinidin on human adipose mesenchymal stem cell differentiation into adipocytes, chondrocytes and osteocytes

BACKGROUND

Anthocyanidins are plant phytochemicals found at high concentrations in berries, vegetables and flowers. Anthocyanidins have been extensively investigated due to their antioxidative, antidiabetic and anti-inflammatory effects. Few studies show that anthocyanidins decrease obesity and improve bone density. However, the effects of anthocyanidins on tissue regeneration have not been sufficiently clarified. Human mesenchymal stem cells (MSCs) are multipotent adult stem cells responsible for the regeneration of fat, bone and cartilage. Although MSCs are often used for screening of biologically active compounds, so far, the effect of anthocyanidins on MSC differentiation has not been addressed.

PURPOSE

The aim of this study was to analyse the effect of anthocyanidins malvidin, cyanidin and delphinidin on adipose tissue-derived MSC differentiation into adipocytes, osteocytes and chondrocytes.

STUDY DESIGN AND METHODS

Differentiation into adipocytes, osteocytes and chondrocytes was carried out in the defined cell culture conditions in the presence or absence of malvidin, cyanidin and delphinidin. The differentiation was confirmed by cytochemical staining and tissue-specific gene and protein expression. Antiobesity and anti-diabetes drug liraglutide was used as a reference drug in this study.

RESULTS

Delphinidin inhibited MSC adipogenesis and downregulated FABP4 and adiponectin genes. Malvidin induced a significantly higher accumulation of calcium deposits in MSCs comparing to untreated MSCs, as well as upregulated the osteocyte-specific gene BMP-2 and Runx-2 expression and induced BMP-2 secretion. Cyanidin and delphinidin demonstrated a chondrogenesis stimulating effect by upregulation of Col2a1 and aggrecan.

CONCLUSION

Altogether, our data show that anthocyanidins malvidin, cyanidin and delphinidin exert favourable effects on MSC osteogenesis and chondrogenesis whereas delphinidin inhibits adipogenesis. These results suggest that anthocyanidin effects on tissue regeneration could be further analysed in depth in vivo.

Energetic and electronic computation of the two-hydrogen atom donation process in catecholic and non-catecholic anthocyanidins

Antioxidant activity of anthocyanidins is greatly affected by the 3-hydroxyl group and/or a catecholic moiety. The two-hydrogen atom donation process is frequently used to explain the high antioxidant activity of polyphenolic compounds leading to the formation of stable diketones e.g. 1,2-quinones. Thermodynamic parameters, HOMO and spin density were computed to identify the favoured path, either through the 3-hydroxyl group or through the catecholic moiety in a series of catecholic and non-catecholic 3-oxy- (and deoxy)-anthocyanidins. DFT calculations showed that the donation process in non-catecholic anthocyanidins depended on the substituents on ring B. Anthocyanidins with 3',5'-diOMe groups showed donation through 3,4'-OH or, otherwise, through 3,5-OH groups. Catecholic 3-oxyanthocyanidins, on the other hand, showed donation through the 3,4'-OH path rather than the catecholic path (4',3'-path). The 3,4'-path was favoured by the formation of planar 3-radicals in the first step and the stabilization of 4'-radicals in the second step by H-bonding with the 3'-OH group.

Exosomal formulation of anthocyanidins against multiple cancer types

Over the last two decades, berries and berry bioactives, particularly anthocyanins and their aglycones anthocyanidins (Anthos) have demonstrated excellent anti-oxidant, anti-proliferative, apoptotic and anti-inflammatory properties. However, their physicochemical and pharmacokinetic limitations such as, low permeability, and poor oral bioavailability are considered as unfavorable properties for development as drugs. Therefore there is a need to develop systems for efficient systemic delivery and robust bioavailability. In this study we prepared nano-formulation of bilberry-derived Anthos using exosomes harvested from raw bovine milk. Exosomal formulation of Anthos enhanced antiproliferative and anti-inflammatory effects compared with the free Anthos against various cancer cells in vitro. Our data also showed significantly enhanced therapeutic response of exosomal-Anthos formulation compared with the free Anthos against lung cancer tumor xenograft in nude mice. The Anthos showed no signs of gross or systemic toxicity in wild-type mice. Thus, exosomes provide an effective alternative for oral delivery of Anthos that is efficacious, cost-effective, and safe, and this regimen can be developed as a non-toxic, widely applicable therapeutic agent.

Flavonoid intake from vegetables and fruits is inversely associated with colorectal cancer risk: a case-control study in China

Flavonoids may play an important role in the protective effects of vegetables, fruits and tea against colorectal cancer. However, associations between flavonoids and colorectal cancer risk are inconsistent, and a few studies have evaluated the effect of flavonoids from different dietary sources separately. This study aimed to evaluate associations of flavonoids intake from different dietary sources with colorectal cancer risk in a Chinese population. From July 2010 to December 2015, 1632 eligible colorectal cancer cases and 1632 frequency-matched controls (age and sex) completed in-person interviews. A validated FFQ was used to estimate dietary flavonoids intake. Multivariate logistical regression models were used to calculate the OR and 95 % CI of colorectal cancer risk after adjusting for various confounders. No significant association was found between total flavonoids and colorectal cancer risk, with an adjusted OR of 1·06 (95 % CI 0·85, 1·32) comparing the highest with the lowest quartile. Anthocyanidins, flavanones and flavones intakes from total diet were found to be inversely associated with colorectal cancer risk. Compared with the lowest quartile, the adjusted OR for the highest quartile were 0·80 (95 % CI 0·64, 1·00) for anthocyanidins, 0·28 (95 % CI 0·22, 0·36) for flavanones and 0·54 (95 % CI 0·43, 0·67) for flavones. All subclasses of flavonoids from vegetables and fruits were inversely associated with colorectal cancer. However, no significant association was found between tea flavonoids and colorectal cancer risk. These data indicate that specific flavonoids, specifically flavonoids from vegetables and fruits, may be linked with the reduced risk of colorectal cancer.

Suppression of β-catenin Signaling Pathway in Human Prostate Cancer PC3 Cells by Delphinidin

Delphinidin possesses strong anti-oxidant, anti-inflammatory, and anti-cancer properties. Suppression of the Wnt/β-catenin signaling pathway is a potential strategy for chemoprevention and therapy. As aberrant activation of the β-catenin signaling pathway contributes to prostate cancer progression, we evaluated the effect of delphinidin on this pathway in human PC3 prostate cancer cells. An MTT assay showed that treatment with delphinidin (15–180 μM, 72 hours) resulted in a dose-dependent growth inhibition of cells. Treatment with delphinidin increased the phosphorylation of serine or threonine residues on β-catenin and decreased the levels of cytoplasmic β-catenin. Moreover, treatment with delphinidin inhibited the nuclear translocation of β-catenin and the expression of β-catenin target genes such as cyclin D1, c-myc, Axin-2, and T cell factor-1. Delphinidin also induced the phosphorylation of glycogen synthase kinase 3β and the expression of adenomatous polyposis coli and Axin proteins. Our results indicate that inhibition of cell growth by delphinidin is mediated, at least in part, through modulation of the β-catenin signaling pathway. We suggest that delphinidin is a potent inhibitor of Wnt/β-catenin signaling in prostate cancer cells.

Development and validation of a liquid chromatography method for anthocyanins in strawberry (Fragaria spp.) and complementary studies on stability, kinetics and antioxidant power

A RPLC-DAD method for the analysis of eight anthocyanins was developed, validated and applied to strawberry extracts. The chromatographic method was conducted under gradient elution in acidulated water-methanol mobile phase and octadecyl-silica columns. An ultrasound extraction procedure was optimized by a 3(2) factorial design (%HCl in methanol, temperature, and time) and response surface methodology. Method validation was performed according to the following parameters: linearity (R(2)>0.99, p-value<10(-4), F>725), LOD (3-7 μmol L(-1)) and LOQ (9-22 μmol L(-1)), selectivity/specificity (baseline separation of all analytes and peak purity), instrumental precision (<6.4%CV), repeatability (<6.3%CV) and intermediate precision (<9.9%CV), recovery (83-99%), robustness (mobile phase pH, column temperature and flow rate) and stability (high temperatures and storage; 1st order kinetics). The antioxidant power of anthocyanins was measured on-line (ABTS(+) reaction; Trolox as reference). Ten strawberry extracts were quantified (average values: 24.2 μg/g for cyanidin-3-glucoside and 49.1 μg/g for pelargonidin-3-glucoside).

Surface-enhanced Raman scattering (SERS) study of anthocyanidins

Anthocyanins are an important class of natural compounds responsible for the red, purple and blue colors in a large number of flowers, fruits and cereal grains. They are polyhydroxy- and polymethoxy-derivatives of 2-phenylbenzopyrylium (flavylium) salts, which are present in nature as glycosylated molecules. The aim of the present study is to assess the identification of anthocyanidins, i.e. anthocyanins without the glycosidic moiety, by means of surface-enhanced Raman spectroscopy (SERS), a very chemically-specific technique which is moreover sensitive to subtle changes in molecular structures. These features can lead to elect SERS, among the spectroscopic tools currently at disposal of scientists, as a technique of choice for the identification of anthocyanidins, since: (1) anthocyanidins structurally present the same benzopyrylium moiety and differentiate only for the substitution pattern on their phenyl ring, (2) different species are present in aqueous solution depending on the pH. It will be demonstrated that, while resonance Raman spectra of anthocyanidins are very similar to one another, SER spectra show greater differences, leading to a further step in the identification of such important compounds in diluted solutions by means of vibrational spectroscopy. Moreover, the dependence on the pH of the six most common anthocyanidins, i.e. cyanidin, delphinidin, pelargonidin, peonidin, malvidin and petunidin, is studied. To the best of the authors' knowledge, a complete SERS study of such important molecules is reported in the present work for the first time.

Antidepressant-like activity of anthocyanidins from Hibiscus rosa-sinensis flowers in tail suspension test and forced swim test

Aim:

Flowers of Hibiscus rosa-sinensis Linn (Malvaceae) popularly known as “China-rose flowers” contain flavonoids. Flavonoids have been found to have antidepressant activity. The aim of the present study is to evaluate the antidepressant activity of flavonoids in H. rosa-sinensis flowers with possible involvement of monoamines.

Materials and Methods:

Anti-depressant activity of methanol extract containing anthocyanins (MHR) (30 and 100 mg/kg) and anthocyanidins (AHR) (30 and 100 mg/ kg) of H. rosa-sinensis flowers were evaluated in mice using behavioral tests such as tail suspension test (TST) and forced swim test (FST). The mechanism of action involved in antidepressant activity was investigated by observing the effect of extract after pre-treatment with low dose haloperidol, prazosin and para-chlorophenylalanine (p-CPA).

Results:

Present study exhibited significant decrease in immobility time in TST and FST, similar to that of imipramine (10 mg/kg, i.p.) which served as a positive control. The extract significantly attenuated the duration of immobility induced by Haloperidol (50 μg/ kg, i.p., a classical D₂-like dopamine receptor antagonist), Prazosin (62.5 μg/kg, i.p., an α₁-adrenoceptor antagonist) and p-chlorophenylalanine (100 mg/kg, i.p., × 3 days; an inhibitor of serotonin synthesis) in both TST and FST.

Conclusion:

It can be concluded that MHR and AHR possess potential antidepressant activity (through dopaminergic, noradrenergic and serotonergic mechanisms) and has therapeutic potential in the treatment of CNS disorders and provides evidence at least at preclinical levels.

Difficulty for consumers in choosing commercial bilberry supplements by relying only on product label information

Background:

Various kinds of bilberry supplements have recently become available on the market. However, it is doubtful whether consumers receive accurate information to be able to compare different supplements.

Objective:

We aimed to investigate whether consumers can obtain the expected benefits by relying only on the information printed on the product labels of commercial bilberry supplements.

Materials and Methods:

The quality of 20 supplements was investigated by the spectrophotometric method and ultra high performance liquid chromatography (UHPLC). Each peak was identified by liquid chromatography–mass spectrometry and quantified using an external standard. The percentage of the actual measured value relative to the indicated value on the product label was determined using the spectrophotometric method. The daily dosage was calculated from the total amount of anthocyanins quantified by UHPLC and information on the product label.

Results:

In 14 of 20 supplements, the total anthocyanin content expressed as delphinidin equivalents was within 20% of the labeled value. However, the extent of degradation could not be determined by the spectrophotometric method. In fresh bilberry fruit, anthocyanidins were barely detected. In 8 of 20 supplements, the anthocyanidin content was >1.0%. The daily dosage of anthocyanins varied by about 66-fold among supplements, and the dosage of 6 supplements was less than the recommended level in Japan.

Conclusions:

Consumers cannot always obtain the expected benefits by relying only on product label information. Therefore, new rules concerning product label information are required to make it possible for consumers to take the equivalent amounts of anthocyanins for whichever bilberry supplement they choose.

Dietary flavonoid intake and risk of stomach and colorectal cancer

Stomach and colorectal cancers are common cancers and leading causes of cancer deaths. Because the alimentary tract can interact directly with dietary components, stomach and colorectal cancer may be closely related to dietary intake. We systematically searched published literature written in English via PubMed by searching for terms related to stomach and colorectal cancer risk and dietary flavonoids up to June 30, 2012. Twenty-three studies out of 209 identified articles were finally selected for the analysis. Log point effect estimates and the corresponding standard errors were calculated using covariate-adjusted point effect estimates and 95%CIs from the selected studies. Total dietary flavonoid intake was not associated with a reduced risk of colorectal or stomach cancer [odds ratio (OR) (95%CI) = 1.00 (0.90-1.11) and 1.07 (0.70-1.61), respectively]. Among flavonoid subclasses, the intake of flavonols, flavan-3-ols, anthocyanidins, and proanthocyanidins showed a significant inverse association with colorectal cancer risk [OR (95%CI) = 0.71 (0.63-0.81), 0.88 (0.79-0.97), 0.68 (0.56-0.82), and 0.72 (0.61-0.85), respectively]. A significant association was found only between flavonols and stomach cancer risk based on a limited number of selected studies [OR (95%CI) = 0.68 (0.46-0.99)]. In the summary estimates from case-control studies, all flavonoid subclasses except flavones and flavanones were inversely associated with colorectal cancer risk, whereas neither total flavonoids nor any subclasses of flavonoids were associated with colorectal cancer risk in the summary estimates based on the cohort studies. The significant association between flavonoid subclasses and cancer risk might be closely related to bias derived from the case-control design. There was no clear evidence that dietary flavonoids are associated with reduced risk of stomach and colorectal cancer.