Flavonoids: a review of probable mechanisms of action and potential applications

Orientin, a Bio-Flavonoid from Trigonella hamosa L., Regulates COX-2/PGE-2 in A549 Cell Lines via miR-26b and miR-146a

Cancer is a severe health condition and considered one of the major healthcare issues and is in need of innovative strategy for a cure. The current study aimed to investigate the chemical profile of Trigonella hamosa L. and a potential molecular approach to explain its regulation in cancer progression through an inflammatory mediator (COX-2) in A549 non-small lung cancer cell lines via in silico, mechanistic and molecular aspects. T. hamosa was extracted and then subjected to a CCK-8 cell viability assay in different cancer cell lines including MDA-MB-231, A549 and HCT-116. Total extract was subjected to several chromatographic techniques to yield orientin (OT); the structure was elucidated by inspection of NMR spectroscopic data. To achieve anticancer effects of OT, a cell viability assay using a CCK-8 kit, immunoprecipitation by Western blot, cell migration using a wound healing assay, cell invasion using a Matrigel-Transwell assay, apoptosis by AO/EB dual staining, flow cytometric analysis and DAPI staining, a silenced COX-2 model to determine PGE-2 production and real-time PCR and Western blot of BCL-2, CYP-1A1, iNOS and COX-2 markers were carried out. The results demonstrated that OT decreased the cell proliferation and controlled cell migration and invasive properties. OT destabilized the COX-2 mRNA and downregulated its expression in A549 cell lines. Virtual binding showed interaction (binding energy −10.43) between OT and COX-2 protein compared to the selective COX-2 inhibitor celecoxib (CLX) (binding energy −9.4). The OT-CLX combination showed a superior anticancer effect. The synergistic effect of OT-CLX combination was noticed in controlling the migration and invasion of A549 cell lines. OT-CLX downregulated the expression of BCL-2, iNOS and COX-2 and activated the proapoptotic gene CYP-1A1. OT mitigated the COX-2 expression via upregulation of miR-26b and miR-146a. Interestingly, COX-2-silenced transfected A549 cells exhibited reduced expression of miR-26b and miR-146a. The findings confirmed the direct interaction of OT with COX-2 protein. PGE-2 expression was quantified in both naïve and COX-2-silenced A549 cells. OT downregulated the release of PGE-2 in both tested conditions. These results confirmed the regulatory effect of OT on A549 cell growth in a COX-2-dependent manner. OT activated apoptosis via activation of CYP-1A1 expression in an independent manner. These results revealed that the OT-CLX combination could serve as a potential synergistic treatment for effective inflammatory-mediated anticancer strategies.

Qualitative and Quantitative Analysis of Phenolic Compounds in Spray-Dried Olive Mill Wastewater

The processing of olives for oil production generates the most abundant agro-industrial by-products in the Mediterranean area. The three-phase olive oil extraction process requires the addition of a large amount of water to the system, which is difficult to dispose of for its load of toxic pollutants. On the other hand, olive mill wastewater is a rich source of bioactive substances with various biological properties that can be used as ingredients in the food industry for obtaining functional and nutraceutical foods as well as in the pharmaceutical industry. In this study, we present the results relative to the phenolic compounds detected in dried olive mill wastewaters obtained using a spray dryer. Qualitative and quantitative analyses were obtained by high-pressure liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). In particular, the compounds here discussed are: apigenin (9.55 mg/kg dry weight), caffeic acid (2.89 mg/kg dry weight), catecol (6.12 mg/kg dry weight), p-cumaric acid (5.01 mg/kg dry weight), diosmetin (3.58 mg/kg dry weight), hydroxytyrosol (1.481 mg/kg dry weight), hydroxytyrosyl oleate (564 mg/kg dry weight), luteolin (62.38 mg/kg dry weight), luteolin-7-O-glucoside (88.55 mg/kg dry weight), luteolin-4-O-glucoside (11.48 mg/kg dry weight), oleuropein (103 mg/kg dry weight), rutin (48.52 mg/kg dry weight), tyrosol (2043 mg/kg dry weight), vanillin (27.70 mg/kg dry weight), and verbascoside (700 mg/kg dry weight). The results obtained highlighted that the use of dehumidified air as a drying medium, with the addition of maltodextrin, appears to be an effective way to produce a phenol-rich powder to be included in food formulations as well as in pharmaceutical preparations having different biological properties.

A Flavonoid-Rich Extract of Sambucus nigra L. Reduced Lipid Peroxidation in a Rat Experimental Model of Gentamicin Nephrotoxicity

The use of gentamicin (GM) is limited due to its nephrotoxicity mediated by oxidative stress. This study aimed to evaluate the capacity of a flavonoid-rich extract of Sambucus nigra L. elderflower (SN) to inhibit lipoperoxidation in GM-induced nephrotoxicity. The HPLC analysis of the SN extract recorded high contents of rutin (463.2 ± 0.0 mg mL−1), epicatechin (9.0 ± 1.1 µg mL−1), and ferulic (1.5 ± 0.3 µg mL−1) and caffeic acid (3.6 ± 0.1 µg mL−1). Thirty-two Wistar male rats were randomized into four groups: a control group (C) (no treatment), GM group (100 mg kg−1 bw day−1 GM), GM+SN group (100 mg kg−1 bw day−1 GM and 1 mL SN extract day−1), and SN group (1 mL SN extract day−1). Lipid peroxidation, evaluated by malondialdehyde (MDA), and antioxidant enzymes activity—superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX)—were recorded in renal tissue after ten days of experimental treatment. The MDA level was significantly higher in the GM group compared to the control group (p < 0.0001), and was significantly reduced by SN in the GM+SN group compared to the GM group (p = 0.021). SN extract failed to improve SOD, CAT, and GPX activity in the GM+SN group compared to the GM group (p > 0.05), and its action was most probably due to the ability of flavonoids (rutin, epicatechin) and ferulic and caffeic acids to inhibit synthesis and neutralize reactive species, to reduce the redox-active iron pool, and to inhibit lipid peroxidation. In this study, we propose an innovative method for counteracting GM nephrotoxicity with a high efficiency and low cost, but with the disadvantage of the multifactorial environmental variability of the content of SN extracts.

Comparative Evaluation of the Potential Antitumor of Helleborus purpurascens in Skin and Breast Cancer

In the field of oncology, the plant kingdom has an inexhaustible supply of bioactive compounds. Phytochemical compounds isolated from Helleborus species have been found to be useful in various chronic diseases. This has brought Helleborus to the attention of medical researchers. H. purpurascens is a plant characteristic of the Carpathian area, known since ancient times for its beneficial effects. The aim of the study was to evaluate the flavonoids composition of a hydroalcoholic extract of H. purpurascens, as well as to assess its antioxidant activity and antitumor potential at the level of two healthy cell lines and four tumor cell lines. In addition, the expression of the genes involved in the apoptotic process (Bcl-2, Bad, and Bax) were evaluated. The results indicated that the extract has a high concentration of flavonoids, such as epicatechin, quercetin, and kaempferol. The extract has an increased antioxidant activity, very similar to that of the standard, ascorbic acid and cytotoxic effects predominantly in the breast cancer cell line, being free of cytotoxic effects in healthy cell lines. Underlying the cytotoxic effect is the induction of the process of apoptosis, which in the present study was highlighted by decreasing the expression of anti-apoptotic genes (Bcl-2) and increasing the expression of pro-apoptotic genes (Bad and Bax). In conclusion, the hydroalcoholic extract of H. purpurascens can be considered an important source for future medical applications in cancer therapy.

Polarity Directed Appraisal of Pharmacological Potential and HPLC-DAD Based Phytochemical Profiling of Polygonum glabrum Willd

The present study was designed to evaluate polarity-dependent extraction efficiency and pharmacological profiling of Polygonum glabrum Willd. Crude extracts of leaves, roots, stems, and seeds, prepared from solvents of varying polarities, were subjected to phytochemical, antioxidant, antibacterial, antifungal, antidiabetic, and cytotoxicity assays. Maximum extraction yield (20.0% w/w) was observed in the case of an acetone:methanol (AC:M) root extract. Distilled water:methanol (W:M) leaves extract showed maximum phenolic contents. Maximum flavonoid content and free radical scavenging potential were found in methanolic (M) seed extract. HPLC-DAD quantification displayed the manifestation of substantial quantities of quercetin, rutin, gallic acid, quercetin, catechin, and kaempferol in various extracts. The highest ascorbic acid equivalent total antioxidant capacity and reducing power potential was found in distilled water roots and W:M leaf extracts, respectively. Chloroform (C) seeds extract produced a maximum zone of inhibition against Salmonella typhimurium. Promising protein kinase inhibition and antifungal activity against Mucor sp. were demonstrated by C leaf extract. AC:M leaves extract exhibited significant cytotoxic capability against brine shrimp larvae and α-amylase inhibition. Present results suggest that the nature of pharmacological responses depends upon the polarity of extraction solvents and parts of the plant used. P. glabrum can be considered as a potential candidate for the isolation of bioactive compounds with profound therapeutic importance.

Effect of Hydroxyl Groups Esterification with Fatty Acids on the Cytotoxicity and Antioxidant Activity of Flavones

Flavonoids and polyunsaturated fatty acids due to low cytotoxicity in vitro studies are suggested as potential substances in the prevention of diseases associated with oxidative stress. We examined novel 6-hydroxy-flavanone and 7-hydroxy-flavone conjugates with selected fatty acids (FA) of different length and saturation and examined their cytotoxic and antioxidant potential. Our findings indicate that the conjugation with FA affects the biological activity of both the original flavonoids. The conjugation of 6-hydroxy-flavanone increased its cytotoxicity towards prostate cancer PC3 cells. The most noticeable effect was found for oleate conjugate. A similar trend was observed for 7-hydroxy-flavone conjugates with the most evident effect for oleate and stearate. The cytotoxic potential of all tested conjugates was not specific towards PC3 because the viability of human keratinocytes HaCaT cells decreased after exposure to all conjugates. Additionally, we showed that esterification of the two flavonoids decreased their antioxidant activity compared to that of the original compounds. Of all the tested compounds, only 6-sorbic flavanone showed a slight increase in antioxidant potential compared to that of the original compound. Our data show that conjugated flavonoids are better absorbed and enhance cytotoxic effects, but the presence of FA lowered the antioxidant potential.

Biomedical applications of tannic acid

Tannic Acid (TA) is a naturally occurring antioxidant polyphenol that has gained popularity over the past decade in the field of biomedical research for its unique biochemical properties. Tannic acid, typically extracted from oak tree galls, has been used in many important historical applications. TA is a key component in vegetable tanning of leather, iron gall ink, red wines, and as a traditional medicine to treat a variety of maladies. The basis of TA utility is derived from its many hydroxyl groups and its affinity for forming hydrogen bonds with proteins and other biomolecules. Today, the study of TA has led to the development of many new pharmaceutical and biomedical applications. TA has been shown to reduce inflammation as an antioxidant, act as an antibiotic in common pathogenic bacterium, and induce apoptosis in several cancer types. TA has also displayed antiviral and antifungal activity. At certain concentrations, TA can be used to treat gastrointestinal disorders such as hemorrhoids and diarrhea, severe burns, and protect against neurodegenerative diseases. TA has also been utilized in biomaterials research as a natural crosslinking agent to improve mechanical properties of natural and synthetic hydrogels and polymers, while also imparting anti-inflammatory, antibacterial, and anticancer activity to the materials. TA has also been used to develop thin film coatings and nanoparticles for drug delivery. In all, TA is fascinating molecule with a wide variety of potential uses in pharmaceuticals, biomaterials applications, and drug delivery strategies.

Reactive oxygen species: Key players in the anticancer effects of apigenin?

Reactive oxygen species (ROS) exhibit a double-edged sword in cancer-hence their modulation has been an attractive strategy in cancer prevention and therapy. The abundance of scientific information on the pro-oxidant effects of apigenin in cancer cells suggests the crucial role of ROS in its mechanisms of action. Although apigenin is known to enhance the cellular ROS levels to cytotoxic degrees in cancer cells in vitro, it remains to be determined if these pro-oxidant effects prevail or are relevant in experimental tumor models and clinical trials. Here, we critically examine the pro-oxidant and antioxidant effects of apigenin in cancer to provide insightful perspectives on the association between its ROS-modulating action and anticancer potential. We also discussed these effects in a cell/tissue type-specific context to highlight the factors influencing the switch between antioxidant and pro-oxidant effects. Finally, we raised some questions that need addressing for the potential translation of these studies into clinical applications. Further research into this duality in oxidant actions of apigenin, especially in vivo, may enable better exploitation of its anticancer potential. PRACTICAL APPLICATION: Apigenin is a naturally occurring compound found in chamomile flowers, parsley, celery, peppermint, and citrus fruits. Many human trials of dietary interventions with apigenin-containing herbs and flavonoid mixture on oxidative stress markers, for instance, point to their antioxidant effects and health benefits in many diseases. Preclinical studies suggest that apigenin alone or its combination with chemotherapeutics has a strong anti-neoplastic effect and can induce ROS-mediated cytotoxicity at concentrations in the micromolar (μM) range, which may not be feasible with dietary interventions. Enhancing the in vivo pharmacokinetic properties of apigenin may be indispensable for its potential cancer-specific pro-oxidant therapy and may provide relevant information for clinical studies of apigenin either as a single agent or an adjuvant to chemotherapeutics.

The role of polyphenols in overcoming cancer drug resistance: a comprehensive review

Chemotherapeutic drugs are used to treat advanced stages of cancer or following surgery. However, cancers often develop resistance against drugs, leading to failure of treatment and recurrence of the disease. Polyphenols are a family of organic compounds with more than 10,000 members which have a three-membered flavan ring system in common. These natural compounds are known for their beneficial properties, such as free radical scavenging, decreasing oxidative stress, and modulating inflammation. Herein, we discuss the role of polyphenols (mainly curcumin, resveratrol, and epigallocatechin gallate [EGCG]) in different aspects of cancer drug resistance. Increasing drug uptake by tumor cells, decreasing drug metabolism by enzymes (e.g. cytochromes and glutathione-S-transferases), and reducing drug efflux are some of the mechanisms by which polyphenols increase the sensitivity of cancer cells to chemotherapeutic agents. Polyphenols also affect other targets for overcoming chemoresistance in cancer cells, including cell death (i.e. autophagy and apoptosis), EMT, ROS, DNA repair processes, cancer stem cells, and epigenetics (e.g. miRNAs).

Natural products as a therapy to combat against SARS-CoV-2 virus infection

The novel coronavirus infection (COVID-19) first reported in December 2019, has become serious global life-threatening disease that has created huge health care crises. Despite huge number of clinical trials for drug and vaccine, only few successful candidates are in market, which led to problem of demand and supply. The low- and middle-income countries faces major health crisis due to financial issues. Studies to search plant originated natural bioactive molecules for prophylactic and therapeutic of COVID-19 infection has gained considerable attention, due to their low-cost, easy availability and lesser side effects. Natural products and herbal medicine have long been known for their role in treating respiratory infections and many of them have been approved/under trial as drugs or over-the-counter food additives to lessen the symptoms. It is undisputable fact that herbal/natural molecules’ medicine is still a promising resource and used as precursor for drug discovery to search prospective prophylactic candidate against COVID-19. These bioactive compounds bind with potential therapeutic target of SARS-COV-2 such as ACE II, Spike protein, TMPRESS, RdRp, Main proteases and endoribonuclease and may prevent or at least slow down the SARS-CoV-2 infection. Therefore, several numbers of clinical trials have registered to investigate the potentials of natural product to halt disease progression. The main aim of present chapter is to discuss the potential role of natural molecules which can be used as therapeutic drugs for treatment of COVID-19 and thus helpful to curb down the mortality rate.

AgMYB12, a novel R2R3-MYB transcription factor, regulates apigenin biosynthesis by interacting with the AgFNS gene in celery

Overexpression of AgMYB12 in celery improved the accumulation of apigenin by interacting with the AgFNS gene. Celery is a common vegetable, and its essential characteristic is medicine food homology. A natural flavonoid and a major pharmacological component in celery, apigenin plays an important role in human health. In this study, we isolated a novel R2R3-MYB transcription factor that regulates apigenin accumulation from the celery cultivar 'Jinnan Shiqin' through yeast one-hybrid screening and designated it as AgMYB12. The AgMYB12 protein was located in the nucleus. It showed transcriptional activation activity and bound specifically to the promoter of AgFNS, a gene involved in apigenin biosynthesis. Phylogenetic tree analysis demonstrated that AgMYB12 belongs to the flavonoid branch. It contains two flavonoid-related motifs, SG7 and SG7-2, and shared a highly conserved R2R3 domain with flavonoid-related MYBs. The homologous overexpression of AgMYB12 induced the up-regulation of AgFNS gene expression and accumulation of apigenin and luteolin in celery. Additionally, the expression levels of apigenin biosynthesis-related genes, including AgPAL, AgCHI, AgCHS, Ag4CL, and AgC4H, increased in transgenic celery plants. These results indicated that AgMYB12 acted as a positive regulator of apigenin biosynthesis and activated the expression of AgFNS gene. The current study provides new information about the regulation mechanism of apigenin metabolism in celery and offers a strategy for cultivating the plants with high apigenin content.

A Novel Pathway of Flavonoids Protecting against Inflammatory Bowel Disease: Modulating Enteroendocrine System

Inflammatory bowel disease (IBD) is a comprehensive term for chronic or relapsing inflammatory diseases occurring in the intestinal tract, generally including Crohn's disease (CD) and ulcerative colitis (UC). Presently, the pathogenesis of IBD is unknown, yet multiple factors have been reported to be related with the development of IBD. Flavonoids are phytochemicals with biological activity, which are ubiquitously distributed in edible plants, such as fruits and vegetables. Recent studies have demonstrated impressively that flavonoids have anti-IBD effects through multiple mechanisms. These include anti-inflammatory and antioxidant actions; the preservation of the epithelial barrier integrity, the intestinal immunomodulatory property, and the shaping microbiota composition and function. In addition, a few studies have shown the impact of flavonoids on enterohormones release; nonetheless, there is hardly any work showing the link between flavonoids, enterohormones release and IBD. So far, the interaction between flavonoids, enterohormones and IBD is elucidated for the first time in this review. Furthermore, the inference can be drawn that flavonoids may protect against IBD through modulating enterohormones, such as glucagon-like peptide 1 (GLP-1), GLP-2, dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors), ghrelin and cholecystokinin (CCK). In conclusion, this manuscript explores a possible mechanism of flavonoids protecting against IBD.

In Vitro Antineoplastic and Antiviral Activity and In Vivo Toxicity of Geum urbanum L. Extracts

This study evaluated the in vitro antineoplastic and antiviral potential and in vivo toxicity of twelve extracts with different polarity obtained from the herbaceous perennial plant Geum urbanum L. (Rosaceae). In vitro cytotoxicity was determined by ISO 10993-5/2009 on bladder cancer, (T-24 and BC-3C), liver carcinoma (HEP-G2) and normal embryonic kidney (HEK-293) cell lines. The antineoplastic activity was elucidated through assays of cell clonogenicity, apoptosis induction, nuclear factor kappa B p65 (NFκB p65) activation and total glutathione levels. Neutral red uptake study was applied for antiviral activity. The most promising G. urbanum extract was analyzed by UHPLC–HRMS. The acute in vivo toxicity analysis was carried out following OEDC 423. The ethyl acetate extract of aerial parts (EtOAc-AP) exhibited the strongest antineoplastic activity on bladder cancer cell lines (IC₅₀ = 21.33–25.28 µg/mL) by inducing apoptosis and inhibiting NFκB p65 and cell clonogenicity. EtOAc and n-butanol extracts showed moderate antiviral activity against human adenovirus type 5 and human simplex virus type I. Seventy four secondary metabolites (gallic and ellagic acid derivatives, phenolic acids, flavonoids, etc.) were identified in EtOAc-AP by UHPLC–HRMS. This extract induced no signs of acute toxicity in liver and kidney specimens of H-albino mice in doses up to 210 mg/kg. In conclusion, our study contributes substantially to the detailed pharmacological characterization of G. urbanum, thus helping the development of health-promoting phytopreparations.

Flavonoids containing Vitex negundo extract displayed calcium channels blocking property underlying its anti-diarrheal and anti-spasmodic activities

Diarrhea is a major health problem and despite of interventions, it remains a substantial cause of mortality and morbidity. In this study, a flavonoids-rich Vitex negundo extract was mechanistically evaluated for its effectiveness in diarrheal diseases. The Vitex negundo ethanolic extract was subjected to extraction for isolation of total flavonoids and qualitative phytochemical analysis. The acute toxicity of flavonoids-extract was done in mice to assess its safety and tolerability. The anti-diarrhoeal activity was determined using the castor oil induced diarrhea mouse model at doses of 10, 30 and 100 mg/kg in relation to loperamide (10 mg/kg, oral). The antispasmodic profile was determined by using cut pieces of rabbit’s jejunum in Tyrode’s solutions, employing acetylcholine (0.03μM) as a tissue stabilizer and verapamil, as a calcium channel blocker. The preliminary qualitative analysis of extract revealed different phytochemicals, in addition to flavonoids. The acute toxicity profile showed that the flavonoids-extract is safe and tolerable (LD50 = 1678 mg/kg). In the tissue experiments, the total flavonoids exhibited an EC50 of 1.52 mg/mL and showed maximum relaxation of spontaneous contractions at 5.0 mg/mL and against high-K + induced contractions at 3 mg/mL (EC50 = 0.43 mg/mL). The spasmolytic activity of total flavonoids was comparable to verapamil which suggests that the activity might be due to the blockade of calcium channels. The flavonoids extract (0.1, 0.3 and 1.0 mg/mL) produced an adequate right shift in the calcium concentration response curve as compared to the control (EC50 value = –2.67 mg/mL), which confirmed that the extract has calcium channel blocking activity.

Extraction, purification, structural character and biological properties of propolis flavonoids: A review

Propolis is an aromatic substance which is collected by bees and mixed with bee saliva. The plant sources of propolis are mainly consisted with plant exudates from bark, buds and etc. Flavonoids are secondary metabolites widely found in natural plants, which have a variety of health care functions and are the main active ingredients of propolis. This article summarized the types, active ingredients, pharmacological effects, extraction methods and applications of propolis flavonoids, the aim was to provide the theoretical basis for further research and development of propolis flavonoids.

Enhancing the stability of zein/fucoidan composite nanoparticles with calcium ions for quercetin delivery

In this study, zein and fucoidan-based composite nanoparticles were prepared by the antisolvent precipitation method. The effects of different calcium ion (Ca²⁺, 0-3.0 mM) concentrations on the stability of the composite nanosystems loaded with quercetin were studied under different conditions (pH, temperature, salt concentration, and ultraviolet light irradiation), and the composite nanoparticles were characterized. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions are the main forces underlying the formation of composite nanoparticles. The addition of Ca²⁺ led to improved release of the active substances from the composite nanoparticles in simulated digestive solutions (especially when the Ca²⁺ concentration was 1.5 mM). The composite nanosystems based on alcohol-soluble proteins and anionic polysaccharides with added Ca²⁺ can be potentially applied for the delivery of active substances.

Polyphenols inhibiting MAPK signalling pathway mediated oxidative stress and inflammation in depression

Depression is one of the most debilitating psychiatric disorders affecting people of all ages worldwide. Despite significant heterogeneity between studies, increased inflammation and oxidative stress have been found in depression. Oxidative stress and inflammation are involved in the pathogenesis of depression. In the current review, we discussed the markers of oxidative stress and inflammation in depressive disorder and the association between these markers and the antidepressant treatment. The role of natural polyphenols in regulating various cell signaling pathways related to oxidative stress and inflammation has also been reviewed. The inhibitory effect of polyphenols on several cell signaling pathways reveals the vital role of polyphenols in the prevention and treatment of depressive disorder. Understanding the mechanism of polyphenols implicated in the regulation of cell signaling pathways is essential for the identification of lead compounds and the development of novel effective compounds for the prevention and treatment of depressive disorder.

Oroxin B Attenuates Ovariectomy-Induced Bone Loss by Suppressing Osteoclast Formation and Activity

Background

Osteoclasts are the major players in bone resorption and have always been studied in the prevention and treatment of osteoporosis. Previous studies have confirmed that a variety of flavonoids inhibit osteoporosis and improve bone health mainly through inhibiting osteoclastogenesis. Oroxin B (OB) is a flavonoid compound extracted from traditional Chinese herbal medicine Oroxylum indicum (L.) Vent, exerts potent antitumor and anti-inflammation effect, but its effect on osteoclastogensis remains unknown.

Methods

We comprehensively evaluated the effect of OB on the formation and function of osteoclasts and the underling mechanism by bone marrow-derived macrophage in vitro. In vivo, we used mice ovariectomized model to verify the protective effect of OB.

Results

OB was found to inhibit osteoclast formation and bone resorption function in vitro, in a dose-dependent manner and the increased osteoclastic-related genes induced by RANKL (NFATc1, c-fos, cathepsin K, RANK, MMP9 and TRAP) were also attenuated following OB treatment. Mechanistical investigation showed OB abrogated the increased phosphorylation level of MAPK and NF-κB pathway, and diminished the expression of the vital transcription factors for osteoclastogenesis. OB also prevented ovariectomy (OVX)-induced bone loss by inhibiting osteoclast formation and activity in mice.

Conclusion

Our study demonstrated that OB may act as an anti-osteoporosis agent by inhibiting osteoclast maturation and attenuating bone resorption.

Neuroprotective Potential of Tamarillo (Cyphomandra betacea) Epicarp Extracts Obtained by Sustainable Extraction Process

Tamarillo (Cyphomandra betacea (Cav.) Sendt.), or tree tomato, is a tropical fruit from the Andean region of South America; it is highly rich in vitamins, minerals, and polyphenolic compounds. In this study, extracts from tamarillo epicarp (TE) were obtained by pressurized liquid extraction (PLE), and their in-vitro neuroprotective potential was assessed. A central composite design with response surface methodology was performed to optimize PLE as a function of solvent composition and temperature. Selected response variables were extraction yield, total phenolic content (TPC), total flavonoid content (TFC), total carotenoid content (TCC), antioxidant (ABTS), and anti-inflammatory (LOX) activities, and anti-acetylcholinesterase (AChE) inhibitory capacity. According to the desirability function, the optimal conditions were 100% ethanol and 180°C with a 0.87 desirability value. Next, the anti-butyrylcholinesterase enzyme (BChE), reactive oxygen species (ROS), and reactive nitrogen species (RNS) inhibition as well as cytotoxicity in HK-2, THP-1 monocytes, and SH-5YSY neuroblastoma cell lines were studied for the TE extract obtained under optimized conditions. The optimum TE extract provided the following results: extraction yield (36.25%), TPC (92.09 mg GAE/g extract), TFC (4.4 mg QE/g extract), TCC (107.15 mg CE/g extract), antioxidant capacity (ABTS, IC₅₀ = 6.33 mg/ml extract), LOX (IC₅₀ = 48.3 mg/ml extract), and AChE (IC₅₀ = 97.46 mg/ml extract), and showed no toxicity at concentration up to 120 μg/ml extract for all the tested cell lines. Finally, chemical characterization by liquid chromatography-tandem mass spectrometry (UHPLC-q-TOF-MS/MS) of the optimum TE extract exhibited an important presence of hydroxycinnamic acid derivatives and other phenolic acids as well as quercetin hexoside and rutin, as main metabolites responsible for the observed biological properties. All these results suggested that TE, which represents between 8 and 15% of the total fruit, could become a promising natural by-product with a potential "multitarget" activity against Alzheimer's disease.

Protective effect of green tea and epigallocatechin-3-gallate in a LPS-induced systemic inflammation model

Inflammation causes severe dysregulation of organ functions, via the development of oxidative stress and inflammation damage. Polyphenol compounds found in green tea (GTE), including the most important component epigallocatechin-3-gallate (EGCG), have a great therapeutic potential. Here, protective properties of GTE and EGCG against lipopolysaccharide (LPS)-induced inflammation are explored. To this end, the effects of GTE and EGCG were studied on LPS challenged macrophages. Mice received GTE (250 mg/kg/d/p.o) or EGCG (25 mg/kg/d/i.p.) for 7 d, before the inflammation shock was provoked with a single intraperitoneal injection of LPS. The frequencies of lymphocytes CD4⁺, CD8⁺, NK1-1⁺ and CD4⁺CD25^highFOXP3⁺ (Treg), macrophages CD11b⁺F480⁺, monocytes CD11b⁺Ly6C^low/high, neutrophils CD11b⁺Ly6G⁺, MDSCs CD11b⁺Gr-1^high, M2/N2-like phenotype CD206⁺ and M1-like phenotype CD86⁺ in spleen, bone marrow and peripheral blood were determined. In vitro studies revealed that GTE and EGCG significantly attenuated LPS-induced CD80 expression and increased the CD163 expression, showing a potential to reduce the macrophage inflammatory phenotype. In vivo, GTE and EGCG inhibited the inflammation, mainly by reducing M1-macrophages and increasing Treg cells in the bone marrow. In addition, GTE and EGCG increase M2-macrophages, N2-neutrophils and Tregs in the spleen and blood and block the migration of monocytes from the bone marrow to the peripheral blood. These findings indicate that EGCG and GTE prevent LPS-induced inflammatory damage contributing to restoring the immune system homeostasis.

Emerging Role of Flavonoids as the Treatment of Depression

Depression is one of the most frequently observed psychological disorders, affecting thoughts, feelings, behavior and a sense of well-being in person. As per the WHO, it is projected to be the primitive cause of various other diseases by 2030. Clinically, depression is treated by various types of synthetic medicines that have several limitations such as side-effects, slow-onset action, poor remission and response rates due to complicated pathophysiology involved with depression. Further, clinically, patients cannot be given the treatment unless it affects adversely the job or family. In addition, synthetic drugs are usually single targeted drugs. Unlike synthetic medicaments, there are many plants that have flavonoids and producing action on multiple molecular targets and exhibit anti-depressant action by affecting multiple neuronal transmissions or pathways such as noradrenergic, serotonergic, GABAnergic and dopaminergic; inhibition of monoamine oxidase and tropomyosin receptor kinase B; simultaneous increase in nerve growth and brain-derived neurotrophic factors. Such herbal drugs with flavonoids are likely to be useful in patients with sub-clinical depression. This review is an attempt to analyze pre-clinical studies, structural activity relationship and characteristics of reported isolated flavonoids, which may be considered for clinical trials for the development of therapeutically useful antidepressant.

Biochemical Characterization of a Novel Prenyltransferase from Streptomyces sp. NT11 and Development of a Recombinant Strain for the Production of 6-Prenylnaringenin

Prenyl groups increase the lipophilicity of flavonoids, endowing them with a special activity, selectivity, and pharmacological properties by prenylation. Herein, a novel prenyltransferase (ShFPT) gene from Streptomyces sp. NT11 was expressed in Escherichia coli, and its biochemical characteristics were determined. ShFPT exhibited high selectivity to prenylate naringenin at C-6 to generate 6-prenylnaringenin. The optimal activity was observed at pH 6.0 and 55 °C. The K_cat and K_m for naringenin were 0.0095 s^-1 and 0.20 mM, respectively. Several promiscuous kinase and isopentenyl phosphate kinase genes were screened to develop the most efficient dimethylallyl diphosphate (DMAPP) synthesis pathway for 6-prenylnaringenin synthesis in E. coli. The 6-prenylnaringenin production was improved by changing the induction strategies and optimizing the bioconversion conditions. Finally, 6-prenylnaringenin production reached the highest yield of 69.9 mg/L with average productivity of 4.0 mg/L/h after 16 h incubation, which is the highest yield for any prenylated flavonoid reported to date in E. coli. Therefore, this study provides an efficient method for 6-prenylnaringenin production and reveals the DMAPP synthesis pathway.

Sorghum halepense (L.) Pers rhizomes inhibitory potential against diabetes and free radicals

Background

Owing to the side effects of synthetic medicine and less effectiveness against different syndromes, the researchers have focused on phytotherapy to overcome these problems. The purpose of this project was to study the in vitro phytochemical, cytotoxic, total phenolic, antioxidant and antidiabetic activities of the methanol extract of the rhizome of Sorghum halepense (L.) Pers and its n-hexane, chloroform and aqueous fractions. Thereafter, to conduct in vivo evaluation of the effective extract for its antidiabetic and antioxidant characteristics.

Methods

Cytotoxic, total phenolic content and antidiabetic properties were ascertained by brine shrimps lethality, Folin- Ciocalteu reagent and alpha-amylase inhibition assays respectively while antioxidant activities were investigated through DPPH, ABTS and H2O2 assays. The methanolic extract was assessed in vivo for its antidiabetic and antioxidant activities by using Wistar albino rats.

Results

The phytochemical investigation of the methanolic extract and its unlike fractions revealed the availability of alkaloids, cardiac glycosides, flavonoids, terpenes, steroids, carbohydrate and proteins while lack of saponins and gums in methanolic extract. Steroids and carbohydrates were only present in aqueous and chloroform fraction respectively while both fractions contained proteins and alkaloids. Cardiac glycosides and flavonoids were absent in aqueous and chloroform fractions respectively. The highest brine shrimps lethality (70.5 ± 1.2), total phenolic content (28.30 ± 1.3 mg GAE/g), free radicals scavenging potential i.e. DPPH (40.02%), ABTS (40.48%) and H2O2 (50.85%) and alpha amylase inhibition (61.87%) was shown by the methanolic extract. The in vivo results did not disclose any sign of acute toxicity. The diabetic control showed a noteworthy (P < 0.05) decline in weight, HDL and glutathione and a raised level of bilirubin, blood glucose, urea, creatinine, triglyceride, LDL, VLDL, ALT, ALP, AST, SOD, catalase. The mentioned alterations were restored considerably (P < 0.05) by treatment of diabetic rats with methanolic extract of Sorghum halepense (L.) Pers (150 and 300 mg/kg b.w.).

Conclusion

It is concluded that the extract of rhizomes of Sorghum halepense (L.) Pers is an effective fount of antioxidant and anti-diabetic compounds. Further analysis is needed to sharpen its pharmacological activities.

Nut intake and hyperuricemia risk in young adults

OBJECTIVE

The relationship between dietary nut intake and hyperuricemia risk remains unclear. The aim of this study was to investigate the relationship between different nut intake and hyperuricemia risk with a cross-sectional study.

DESIGN

A semi-quantitative FFQ was adopted to collect dietary information. Biochemical and anthropometric parameters were measured by standard methods. Multivariate-adjusted logistic regression models were implemented to analyse the relationship between individual nut intake and hyperuricemia risk.

SETTING

Qingdao University in Shandong Province, China.

PARTICIPANTS

During 2018-2019, a total of 14 056 undergraduates (6862 males and 7194 females) aged 15-25 years participated in the study.

RESULTS

After adjusting for multiple confounding factors, compared with the lowest quartile, the highest quartile intakes of pine nut (95 % CI (0·51, 0·98)) was significantly associated with 29 % reduction in hyperuricemia risk, the highest quartile intake of walnut (OR = 0·78; 95 % CI (0·58, 1·05)) was marginally negatively associated with hyperuricemia risk.

CONCLUSIONS

The present study showed that the relationships between intakes of different nuts and hyperuricemia risk were different. Increased dietary intakes of walnut and pine nut are negatively associated with the hyperuricemia.

Sauropus brevipes ethanol extract negatively regulates inflammatory responses in vivo and in vitro by targeting Src, Syk and IRAK1

CONTEXT

Sauropus brevipes Müll. Arg. (Phyllanthaceae) has been used as an effective ingredient in a decoction for the treatment of diarrhoea. However, there was no report on its modulatory role in inflammation.

OBJECTIVE

This study investigates anti-inflammatory effect of S. brevipes in various inflammation models.

MATERIALS AND METHODS

The aerial part of S. brevipes was extracted with 95% ethanol to produce Sb-EE. RAW264.7 cells pre-treated with Sb-EE were stimulated by lipopolysaccharide (LPS), and Griess assay and PCR were performed. High-performance liquid chromatography (HPLC) analysis, luciferase assay, Western blotting and kinase assay were employed. C57BL/6 mice (10 mice/group) were orally administered with Sb-EE (200 mg/kg) once a day for five days, and peritonitis was induced by an intraperitoneal injection of LPS (10 mg/kg). ICR mice (four mice/group) were orally administered with Sb-EE (20 or 200 mg/kg) or ranitidine (positive control) twice a day for two days, and EtOH/HCl was orally injected to induce gastritis.

RESULTS

Sb-EE suppressed nitric oxide (NO) release (IC₅₀=34 µg/mL) without cytotoxicity and contained flavonoids (quercetin, luteolin and kaempferol). Sb-EE (200 µg/mL) reduced the mRNA expression of inducible NO synthase (iNOS). Sb-EE blocked the activities of Syk and Src, while inhibiting interleukin-1 receptor associated kinases (IRAK1) by 68%. Similarly, orally administered Sb-EE (200 mg/kg) suppressed NO production by 78% and phosphorylation of Src and Syk in peritonitis mice. Sb-EE also decreased inflammatory lesions in gastritis mice.

DISCUSSION AND CONCLUSIONS

This study demonstrates the inhibitory effect of Sb-EE on the inflammatory response, suggesting that Sb-EE can be developed as a potential anti-inflammatory agent.

Investigating Structural Property Relationships to Enable Repurposing of Pharmaceuticals as Zinc Ionophores

The importance of zinc in biology has gained greater recognition in recent years due to its essential contributions to the function of many endogenous enzymes. Disruption of zinc homeostasis may be useful in treating pathological conditions, such as Alzheimer's, and for antiviral purposes. Despite the growth of knowledge and increased interest in zinc, little is known about the structure and function of zinc ionophores. In this study we analyse the Cambridge Structural Database and solution complexation studies found in the literature to identify key functional groups which may confer zinc ionophorism. Pharmaceuticals, nutraceuticals and amino acids with these functionalities were selected to enable us to explore the translatability of ionophoric activity from in vitro assays to cellular systems. We find that although certain species may complex to zinc in the solid and solution states, and may carry ions across simple membrane systems, this does not necessarily translate into ionophoric activity. We propose that the CSD can help refine key functionalities but that ionophoric activity must be confirmed in cellular systems.

The Effectiveness of Sechium edule Jacq. Swartz Extract Changes in the Histopathology of Aspirin-Induced Rat Gastritis Model

BACKGROUND: Gastritis is one of the most common diseases found in internal medicine clinics and daily life. AIM: The purpose of this study was to determine the histopathological changes of gastric rat model of aspirin-induced gastritis. MATERIALS AND METHODS: Group K(−) is a negative control (normal) not given any treatment, Group K(+) is a positive control induced by aspirin 200 mg/kgBW, Group 1 (P1) is a treatment group induced by aspirin 200 mg/kgBW with ethanol extract of chayote 100 mg/kgBW, po, Group 2 (P2) was the treatment group induced by aspirin 200 mg/kgBW with ethanol extract of chayote 200 mg/kgBW, po, Group 3 (P3) was the treatment group induced by aspirin 200 mg/kgBW with ethyl acetate fraction chayote 100 mg/kgBW, PO, Group 4 (P4) was the treatment group induced by aspirin 200 mg/kgBW with ethyl acetate fraction chayote 200 mg/kgBW, PO, and Group 5 (P5) was the treatment group induced by aspirin 200 mg/kgBW with omeprazole 20 mg. RESULTS: Analysis of the results of inflammatory infiltration in gastric histopathology in Groups P1, P2, P3, and P4 showed mild inflammatory infiltration compared to Groups P(5) and K(+). The description of the acinar glands on gastric histopathology showed that the P2 group gave a better picture of the acinar gland repair than the K(+), P2, P3, P4, and P5 groups. CONCLUSION: This study showed that ethanol extracts of squash 200 mg/KgBW own effectiveness as an anti-inflammatory on the improvement of infiltration of inflammatory and picture histopathological gastric mice compared with the ethanol extract of squash 100 mg/kg, the fraction of ethyl acetate chayote 100 mg/KgBW and 200 mg/KgBW and omeprazole 20 mg.

Baicalein suppresses lipopolysaccharide-induced acute lung injury by regulating Drp1-dependent mitochondrial fission of macrophages

Acute lung injury (ALI) and its serious form, the acute respiratory distress syndrome (ARDS) are devastating diseases without effective chemotherapy. Exuberant or uncontrolled proinflammation responses in the lung, also known as "cytokine storms", is one of the main culprits in the pathogenesis of organ failure, and anti-inflammatory therapy is essential to alleviate ALI/ARDS-associated injuries. Emerging evidence suggests that baicalein has potent anti-inflammatory and antioxidant properties. However, the underlined mechanism of baicalein to mitigate inflammation in ALI remains unclear. Herein, we demonstrated a critical role for baicalein in suppressing the inflammatory response of LPS-activated macrophages. We found that mitochondria function was restored in the condition of baicalein. Interestingly, results showed that mitochondrial dysfunction positively correlates with inflammatory cytokine generation at each corresponding baicalein concentration. Further mRNA analysis revealed that baicalein mitigates mitochondrial defects via attenuation of dynamin-related protein 1 (Drp1) expression. These reprogrammed mitochondria prevent their function shift from the ATP synthesis to reactive oxygen species (ROS) production after the LPS challenge, thereby dampening NF-κB-dependent inflammatory cytokine transcription. Baicalein reduces the production of inflammatory mediators TNF-α, MIP-1, IL-6, and diminishes neutrophil influx and severity of endotoxin-mediated ALI. Taken together, our results show that baicalein may serve as a new clinical therapeutic strategy in ALI by modulating Drp1-induced mitochondrial impairment, restraining inflammatory responses, and reducing the severity of lung injury.

Morus alba L. Leaves - Integration of Their Transcriptome and Metabolomics Dataset: Investigating Potential Genes Involved in Flavonoid Biosynthesis at Different Harvest Times

The mulberry leaf is a classic herb commonly used in traditional Chinese medicine. It has also been used as animal feed for livestock and its fruits have been made into a variety of food products. Traditionally, mulberry (Morus alba L.) leaf harvesting after frost is thought to have better medicinal properties, but the underlying mechanism remains largely unsolved. To elucidate the biological basis of mulberry leaves after frost, we first explored the content changes of various compounds in mulberry leaves at different harvest times. Significant enrichment of flavonoids was observed with a total of 224 differential metabolites after frost. Subsequently, we analyzed the transcriptomic data of mulberry leaves collected at different harvest times and successfully annotated 22,939 unigenes containing 1,695 new genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed 26, 20, and 59 unigenes related to flavonoids synthesis in three different groups harvested at different times. We found that the expression levels of flavonoid biosynthesis-related unigenes also increased when harvested at a delayed time, which was consistent with the flavonoid accumulation discovered by the metabolomic analysis. The results indicated that low temperature may be a key trigger in flavonoid biosynthesis of mulberry leaves by increasing the expression of flavonoid biosynthesis-related genes. This study also provided a theoretical basis for the optimal harvest time of mulberry leaves.

Pharmacological validation of Solanum mammosum L. as an anti-infective agent: Role of solamargine

ETHNOPHARMACOLOGICAL RELEVANCE

Fungal and bacterial infections remain a major problem worldwide, requiring the development of effective therapeutic strategies. Solanum mammosum L. (Solanaceae) ("teta de vaca") is used in traditional medicine in Peru to treat fungal infections and respiratory disorders via topical application. However, the mechanism of action remains unknown, particularly in light of its chemical composition.

MATERIALS AND METHODS

The antifungal activity of TDV was determined against Trichophyton mentagrophytes and Candida albicans using bioautography-TLC-HRMS to rapidly identify the active compounds. Then, the minimum inhibitory concentration (MIC) of the fruit crude extract and the active compound was determined to precisely evaluate the antifungal activity. Additionally, the effects of the most active compound on the formation of Pseudomonas aeruginosa biofilms and pyocyanin production were evaluated. Finally, a LC-HRMS profile and a molecular network of TDV extract were created to characterize the metabolites in the fruits' ethanolic extract.

RESULTS

Bioautography-TLC-HRMS followed by isolation and confirmation of the structure of the active compound by 1D and 2D NMR allowed the identification solamargine as the main compound responsible for the anti-Trichophyton mentagrophytes (MIC = 64 μg mL^-1) and anti-Candida albicans (MIC = 64 μg mL^-1) activities. In addition, solamargine led to a significant reduction of about 20% of the Pseudomonas aeruginosa biofilm formation. This effect was observed at a very low concentration (1.6 μg mL^-1) and remained fairly consistent regardless of the concentration. In addition, solamargine reduced pyocyanin production by about 20% at concentrations of 12.5 and 50 μg mL^-1. Furthermore, the LC-HRMS profiling of TDV allowed us to annotate seven known compounds that were analyzed through a molecular network.

CONCLUSIONS

Solamargine has been shown to be the most active compound against T. mentoagrophytes and C. albicans in vitro. In addition, our data show that this compound affects significantly P. aeruginosa pyocyanin production and biofilm formation in our conditions. Altogether, these results might explain the traditional use of S. mammosum fruits to treat a variety of fungal infections and respiratory disorders.

Transcriptomics and Metabolomics Changes Triggered by Inflorescence Removal in Panax notoginseng (Burk.)

The root of Panax notoginseng (Burk.), in which saponins are the major active components, is a famous traditional Chinese medicine used to stop bleeding and to decrease inflammation and heart disease. Inflorescence removal increases the yield and quality of P. notoginseng, but the underlying molecular mechanisms are unknown. Here, the differences between inflorescence-removal treatment and control groups of P. notoginseng were compared using transcriptomics and metabolomics analyses. Illumina sequencing of cDNA libraries prepared from the rhizomes, leaves and roots of the two groups independently identified 6,464, 4,584, and 7,220 differentially expressed genes (DEG), respectively. In total, 345 differentially expressed transcription factors (TFs), including MYB and WRKY family members, were induced by the inflorescence-removal treatment. Additionally, 215 DEGs involved in saponin terpenoid backbone biosynthetic pathways were identified. Most genes involved in the mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways were activated by inflorescence removal. The co-expression analysis showed that the low expression levels of flavonoid biosynthesis-related genes (e.g., C4H and F3H) decreased the biosynthesis and accumulation of some flavonoids after inflorescence removal. The results not only provide new insights into the fundamental mechanisms underlying the poorly studied inflorescence-removal process in P. notoginseng and other rhizome crops, but they also represent an important resource for future research on gene functions during inflorescence-removal treatments and the reproductive stage.

Transcriptome sequencing and metabolomics analyses provide insights into the flavonoid biosynthesis in Torreya grandis kernels

The kernel of Torreya grandis (T. grandis) is a rare nut with a variety of bioactive compounds. Flavonoids are a very important class of bioactive compounds with high antioxidant activity in T. grandis kernels. However, the flavonoid compositions which mainly contribute to antioxidant capacity and the molecular basis of flavonoid biosynthesis in T. grandis remain unclear. Here, transcriptome sequencing and metabolomics analysis for kernels were performed. In total, 124 flavonoids were identified. Among them, 9 flavonoids were highly correlated with antioxidant activity. Furthermore, unigenes encoding CHS, DFR and ANS showed significant correlation with the 9 flavonoids. Transient overexpression of TgDFR1 in tobacco leaves resulted in increased antioxidant activity. Moreover, several transcription factors from MYB, bHLH and bZIP families were identified by co-expression assay, suggesting that they may regulate flavonoid biosynthesis. Our findings provide a molecular basis and new insights into the flavonoid biosynthesis in T. grandis kernels.

The effect of grape seed extract supplementation on oxidative stress and inflammation: A systematic review and meta-analysis of controlled trials

BACKGROUND

Grape seed extract (GSE) seems to have antioxidant and anti-inflammatory properties due to its high polyphenolic content. Nevertheless, the scientific literature in this field is controversial and inconclusive. Therefore, we aimed to conduct a systematic review and meta-analysis of controlled trials to evaluate the effect of supplementation with GSE on biomarkers of oxidative stress and inflammation.

METHODS

Medline, Scopus, Cochrane Library, Google Scholar and Web of Science databases were searched up to 10 September 2020 using appropriate keywords without restrictions. In the systematic review phase, all biomarkers of oxidative stress and inflammation were considered as outcomes. In the meta-analysis phase, six biomarkers were selected as outcomes, and weighted mean difference (WMD) or standardised mean difference (SMD) with 95% confidence interval (CI) was calculated for them using a random-effects model.

RESULTS

Twenty-three studies were included in the systematic review, and 19 studies were included in the meta-analysis. GSE supplementation caused a significant decrease in malondialdehyde (SMD: -1.04, 95% CI: -1.65, -0.42), oxidised low-density lipoprotein (SMD: -0.44, 95% CI: -0.75, -0.13) and high-sensitivity C-reactive protein (WMD: -0.48 mg/L, 95% CI: -0.94, -0.03) and a marginally significant increase in total antioxidant capacity (SMD: 0.49, 95% CI: -0.05, 1.04) but did not significantly influence C-reactive protein (WMD: -0.36 mg/L, 95% CI: -1.02, 0.30) and white blood cell count (WMD: 0.12 × 10⁹ /L, 95% CI: -0.25, 0.48).

CONCLUSION

It appears that GSE supplementation can remarkably modulate the body's redox system, particularly through the inhibition of lipid peroxidation, but has neutral or mildly beneficial effects on inflammatory responses.

Fructose in the kidney: from physiology to pathology

The Warburg effect is a unique property of cancer cells, in which glycolysis is activated instead of mitochondrial respiration despite oxygen availability. However, recent studies found that the Warburg effect also mediates non-cancer disorders, including kidney disease. Currently, diabetes or glucose has been postulated to mediate the Warburg effect in the kidney, but it is of importance that the Warburg effect can be induced under nondiabetic conditions. Fructose is endogenously produced in several organs, including the kidney, under both physiological and pathological conditions. In the kidney, fructose is predominantly metabolized in the proximal tubules; under normal physiologic conditions, fructose is utilized as a substrate for gluconeogenesis and contributes to maintain systemic glucose concentration under starvation conditions. However, when present in excess, fructose likely becomes deleterious, possibly due in part to excessive uric acid, which is a by-product of fructose metabolism. A potential mechanism is that uric acid suppresses aconitase in the Krebs cycle and therefore reduces mitochondrial oxidation. Consequently, fructose favors glycolysis over mitochondrial respiration, a process that is similar to the Warburg effect in cancer cells. Activation of glycolysis also links to several side pathways, including the pentose phosphate pathway, hexosamine pathway, and lipid synthesis, to provide biosynthetic precursors as fuel for renal inflammation and fibrosis. We now hypothesize that fructose could be the mediator for the Warburg effect in the kidney and a potential mechanism for chronic kidney disease.

Investigation of the interaction between Chrysoeriol and xanthine oxidase using computational and in vitro approaches

Xanthine oxidase (XO) plays a vital role in inducing hyperuricemia and increasing the level of superoxide free radicals in blood, and is proved as an important target for gout. Chrysoeriol (CHE) is a natural flavone with potent XO inhibitory activity (IC₅₀ = 2.487 ± 0.213 μM), however, the mechanism of interaction is still unclear. Therefore, a comprehensive analysis of the interaction between CHE and XO was accomplished by enzyme kinetics, isothermal titration calorimetry (ITC), multi-spectroscopic methods, molecular simulation and ADMET. The results showed that CHE acted as a rapid reversible and competitive-type XO inhibitor and its binding to XO was driven by hydrogen bonding and hydrophobic interaction. Moreover, CHE exhibited a strong fluorescence quenching effect through a static quenching procedure and induced conformational changes of XO. Its binding pattern with XO was revealed by docking study and the binding affinity to XO was enhanced by the interactions with key amino acid residues in the active pocket of XO. Further, CHE showed good stability and pharmacokinetic behavior properties in molecule dynamic simulation and ADMET prediction. Overall, this study shed some light on the mechanism of interaction between CHE and XO, also provided some valuable information concerning the future therapeutic application of CHE as natural XO inhibitor.

A comprehensive review: Biological activity, modification and synthetic methodologies of prenylated flavonoids

Prenylated flavonoids, a unique class of flavonoids which combine a flavonoid skeleton and a lipophilic prenyl side-chain, possess great potential biological activities including cytotoxicity, anti-inflammation, anti-Alzheimer, anti-microbial, anti-oxidant, anti-diabetes, estrogenic, vasorelaxant and enzyme inhibition. Recently, prenylated flavonoids have become an indispensable anchor for the development of new therapeutic agents, and have received increasing from medicinal chemists. The prenylated flavonoids have been outstanding developed through isolation, semi or fully synthesis in a very short period of time, which proves the great value in medicinal chemistry researches. In this review, research progress of prenylated flavonoids including natural prenylated flavonoids, structural modification, synthetic methodologies and pharmacological activities was summarized comprehensively. Furthermore, the structure-activity relationships (SARs) of prenylated flavonoids were summarized which provided a basis for the selective design and optimization of multifunctional prenylated flavonoid derivatives for the treatment of multi-factorial diseases in clinic.

Polyphenols Targeting MAPK Mediated Oxidative Stress and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune disorder, predominantly symmetric, which causes joint inflammation, cartilage degeneration and bone erosion, resulting in deformity and the loss of physical function. Although the management of RA has steadily improved, the pathophysiological mechanism is incompletely elucidated, and therapeutic options are still limited. Due to shortcomings in the efficacy or safety profiles of conventional RA therapies, therapeutic alternatives have been considered. Therefore, natural extracts containing polyphenolic compounds can become promising adjuvant agents for RA global management, due to their antioxidant, anti-inflammatory and apoptotic properties. Polyphenols can regulate intracellular signaling pathways in RA and can generate different immune responses through some key factors (i.e., MAPK, interleukins (ILs 1 and 6), tumor necrosis factor (TNF), nuclear factor light k chain promoter of activated receptor (NF-κB), and c-Jun N-terminal kinases (JNK)). The critical function of the Toll like-receptor (TLR)-dependent mitogen-activating protein kinase (MAPK) signaling pathway in mediating the pathogenic characteristics of RA has been briefly discussed. Oxidative stress can trigger a change in transcription factors, which leads to the different expression of some genes involved in the inflammatory process. This review aims to provide a comprehensive perspective on the efficacy of polyphenols in mitigating RA by inhibiting signaling pathways, suggesting future research perspectives in order to validate their use.

Role of Polyphenols in the Metabolism of the Skeletal System in Humans and Animals – A Review

Polyphenols are a group of compounds arousing enormous interest due to their multiple effects on both human and animal health and omnipresence in plants. A number of in vitro and animal model studies have shown that all polyphenols exhibit anti-inflammatory and antioxidant activities, and play a significant role against oxidative stress-related pathologies. They also exert gut promotory effects and prevent chronic degenerative diseases. However, less attention has been paid to the potential influence of polyphenols on bone properties and metabolism. It is well known that proper growth and functioning of the organism depend largely on bone growth and health. Therefore, understanding the action of substances (including polyphenols) that may improve the health and functioning of the skeletal system and bone metabolism is extremely important for the health of the present and future generations of both humans and farm animals. This review provides a comprehensive summary of literature related to causes of bone loss during ageing of the organism (in both humans and animals) and possible effects of dietary polyphenols preventing bone loss and diseases. In particular, the underlying cellular and molecular mechanisms that can modulate skeletal homeostasis and influence the bone modeling and remodeling processes are presented.

Chemoenzymatic Stereoselective Synthesis of trans-Flavan-4-ols via Lipase-Catalyzed Kinetic Resolutions

Flavan-4-ols are a subclass of flavonoids that are present in complex molecules with application in the industrial sector as pigments, antioxidants, or antimitotics, among many others. The most traditional way to achieve their synthesis is from naturally abundant flavanones, asymmetric transfer hydrogenation reactions or bioreduction being well known strategies, while their preparation from racemic flavan-4-ols has been less explored. In this article, we have focused on the synthesis of a series of trans-flavan-4-ols bearing different substitution patterns in the aromatic ring to explore later the potential of lipases as biocatalysts for stereoselective acylation reactions. Therefore, a series of flavanones have been chemically prepared, starting from the corresponding benzaldehydes by aldol condensation with 2′-hydroxyacetophenone in a strongly basic medium, and later transformed into the corresponding racemic trans-flavan-4-ols following a carbonyl reduction, Mitsunobu reaction, and ester deprotection sequence. A screening of lipases and optimization of the reaction conditions for the stereoselective acylation of racemic 2-phenylchroman-4-ol were performed before expanding the best reaction conditions to the kinetic resolution of other 2-arylchroman-4-ols. Interestingly, the combination of AK lipase from Pseudomonas fluorescens as enzyme and vinyl acetate as both acyl donor and solvent allowed the performance of highly asymmetric transformations (E > 200, 50–99% eeS and >99% eeP) under mild reaction conditions (30 °C and 250 rpm).

Fungicide Difenoconazole Induced Biochemical and Developmental Toxicity in Wheat (Triticum aestivum L.)

Difenoconazole is one of the most commonly used fungicides to prevent and treat plant diseases caused by certain fungi. Due to increasing usage, more difenoconazole has been released into the environment and caused environment pollution. However, the potential impact of difenoconazole on plant growth and development and its involved mechanism are unclear. In this study, we discovered that difenoconazole exposure significantly inhibited plant growth, evidenced by the decrease in root dry weight, total root length, and surface area by 20-70%, 43-73%, and 26-66%, respectively, under different regimes of treatment concentrations and periods. Difenoconazole exposure also significantly inhibited shoot growth and development by decreasing 33-61% of the shoot dry weight and 50-65% of the leaf area. Difenoconazole exposure induced plant leaf cells to generate more ROS (O₂^•- and H₂O₂) and MDA, which resulted in a decreased chlorophyll content and then inhibited leaf photosynthesis. Difenoconazole exposure also induced the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POD), and ascorbate peroxidase (APX) in the roots and leaves of the wheat seedlings. SOD and APX activities were higher and more stable in the roots than those in the leaves. Based on our study, plant roots exhibited a more pronounced superoxide radical scavenging ability than plant leaves. In summary, difenoconazole exposure caused oxidative stress, reduced chlorophyll biosynthesis and functions, and then inhibited wheat plant growth and development.

Variation of bitter components of the asparagus juices during lactic acid bacteria fermentation

To investigate the bitterness status of asparagus juices during lactic acid fermentation, Limosilactobacillus fermentum Xd, Lacticaseibacillus paracasei Yd, Lactiplantibacillus plantarum 5-7-3, and their various combinations were used for single and mixed fermentation of asparagus juices. The fermentation characteristics and variation of the main bitter substances were studied. For the single and cofermented samples, the viable counts, pH value, and acidity were ranged from 8.33-8.65 lg CFU/mL, 3.58-3.86, and 6.29-6.52 g/kg, respectively. By sensory evaluation, the bitterness of every fermented sample was continuously reduced by at least 77% during fermentation, and the corresponding content of total saponins, flavonoids, and 9 bitter amino acids showed varying degrees of declination. These results suggested that it was feasible to develop novel low-bitter asparagus juices fermented by the lactic acid bacteria used in this study.

Potential Mechanisms of Plant-Derived Natural Products in the Treatment of Cervical Cancer

Cervical cancer is the second most common gynecological malignancy globally; it seriously endangers women’s health because of its high morbidity and mortality. Conventional treatments are prone to drug resistance, recurrence and metastasis. Therefore, there is an urgent need to develop new drugs with high efficacy and low side effects to prevent and treat cervical cancer. In recent years, plant-derived natural products have been evaluated as potential anticancer drugs that preferentially kill tumor cells without severe adverse effects. A growing number of studies have shown that natural products can achieve practical anti-cervical-cancer effects through multiple mechanisms, including inhibition of tumor-cell proliferation, induction of apoptosis, suppression of angiogenesis and telomerase activity, enhancement of immunity and reversal of multidrug resistance. This paper reviews the therapeutic effects and mechanisms of plant-derived natural products on cervical cancer and provides references for developing anti-cervical-cancer drugs with high efficacy and low side effects.

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

Simple Summary

The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer.

Abstract

Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations.

Citrus flavonoids as potential therapeutic agents: A review

The plants Rutaceae family are known to have contributed a lot toward food and medicine. The most important metabolites of the family are flavonoids. A systematic review was conducted to collect chemical and pharmacological information of flavonoids isolated from family Rutaceae till 2018. A plethora of flavonoids have been isolated and studied systematically for various bioactivities, including anticancer, antibacterial, antiviral, analgesic, antioxidant, antidiabetic, antiinflammatory, in bronchitis, ulcers, and so on. The important groups of flavonoids isolated are naringin, poncirin, rhoifolin, marmesin, hesperidin, tangeretin, nobiletin, glychalcone, glyflavanone, lemairone, acacetin 3,6-di-C-glucoside, vicenin-2, lucenin-2 4'-methyl ether, narirutin 4'-O-glucoside, apigenin 8-C-neohesperidoside, phloretin 3',5'-di-C-glucoside, rutin, rhamnetin, dihydrokaempferol, dihydrokaempferol 3-O-rhamnoside (engeletin) and kaempferol, excavaside A and B, myricetin 3-O-β-D-rutinoside, myricetin 3,3'-di-α-l-rhamnopyranoside, myricetin 3'-α-l-rhamnopyranoside, and others. The flavonoids isolated from the citrus family need to be considered from a nutraceutical, therapeutic, and pharmaceutical point of view for future medicine.

The effect of 24-week continuous intake of quercetin-rich onion on age-related cognitive decline in healthy elderly people: a randomized, double-blind, placebo-controlled, parallel-group comparative clinical trial

Quercetin, a type of flavonoid, is believed to reduce age-related cognitive decline. To elucidate its potential function, we carried out a randomized, double-blind, placebo-controlled, parallel-group comparative clinical trial involving 24-week continuous intake of quercetin-rich onion compared to quercetin-free onion as a placebo. Seventy healthy Japanese individuals (aged 60 to 79 years old) were enrolled in this study. We examined the effect of quercetin-rich onion (the active test food) on cognitive function using the Mini-Mental State Examination, Cognitive Assessment for Dementia iPad version, and Neuropsychiatric Inventory Nursing Home version. The Mini-Mental State Examination scores were significantly improved in the active test food group (daily quercetin intake, 50 mg as aglycone equivalent) compared to the placebo food group after 24 weeks. On the Cognitive Assessment for Dementia iPad version for emotional function evaluation, we found that the scores of the active test food group were significantly improved, suggesting that quercetin prevents cognitive decline by improving depressive symptoms and elevating motivation. On the Neuropsychiatric Inventory Nursing Home version, we found significant effects on reducing the burden on study partners. Taking all the data together, we concluded that 24-week continuous intake of quercetin-rich onion reduces age-related cognitive decline, possibly by improving emotional conditions. Clinical trial register and their clinical registration number: This study was registered with UMIN (approval number UMIN000036276, 5 April 2019).

Potential therapeutic interventions of plant-derived isoflavones against acute lung injury

Acute lung injury (ALI) is a life-threatening syndrome that possibly leads to high morbidity and mortality as no therapy exists. Several natural ingredients with negligible adverse effects have recently been investigated to possibly inhibit the inflammatory pathways associated with ALI at the molecular level. Isoflavones, as phytoestrogenic compounds, are naturally occurring bioactive compounds that represent the most abundant category of plant polyphenols (Leguminosae family). A broad range of therapeutic activities of isoflavones, including antioxidants, chemopreventive, anti-inflammatory, antiallergic and antibacterial potentials, have been extensively documented in the literature. Our review exclusively focuses on the possible anti-inflammatory, antioxidant role of botanicals'-derived isoflavones against ALI and their immunomodulatory effect in experimentally induced ALI. Despite the limited scope covering their molecular mechanisms, isoflavones substantially contributed to protecting from ALI via inhibiting toll-like receptor 4 (TLR4)/Myd88/NF-κB pathway and subsequent cytokines, chemokines, and adherent proteins. Nonetheless, future research is suggested to fill the gap in elucidating the protective roles of isoflavones to alleviate ALI concerning antioxidant potentials, inhibition of the inflammatory pathways, and associated molecular mechanisms.

Antimicrobial Effect of Tea Polyphenols against Foodborne Pathogens: A Review

ABSTRACT

Food contamination by foodborne pathogens is still widespread in many countries around the world, and food safety is a major global public health issue. Therefore, novel preservatives that can guarantee safer food are in high demand. Contrary to artificial food preservatives, tea polyphenols (TPs) are getting wide attention as food additives for being "green," "safe," and "healthy." TPs come from many sources, and the purification technology is sophisticated. Compared with other natural antibacterial agents, the antibacterial effect of TPs is more stable, making them excellent natural antibacterial agents. This review includes a systematic summary of the important chemical components of TPs and the antibacterial mechanisms of TPs against various foodborne pathogens. The potential applications of TPs are also discussed. These data provide a theoretical basis for the in-depth study of TPs.

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