Recent discoveries of anticancer flavonoids

Optimization of Enzyme-Assisted Extraction and Purification of Flavonoids from Pinus koraiensis Nut-Coated Film and Antioxidant Activity Evaluation

Pinus koraiensis nut-coated film is a kind of by-product of nut processing, which has been shown to contain flavonoids, polyphenols, and other substances that can be used to produce natural antioxidant extracts. In this study, response surface methodology (RSM) was used to optimize the extraction process of flavonoids of P. koraiensis nut-coated film (PNF), and macroporous resin HPD600 was used to purify PNF (P-PNF). Its antioxidant activity was examined by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacity, oxygen free radical absorption capacity (ORAC), total oxygen radical capture (TRAP), and iron ion reduction capacity. Under the ideal extraction conditions comprising a cellulase dosage of 90 U/g, a material/liquid ratio of 1:20 (g/mL), and an extraction time of 2 h, the PNF yield was 3.37%. Purification conditions were sample concentration of 2.0 mg/mL, pH of 5, water washing volume of 3 bed volume (BV), eluent ethanol concentration of 50%, and volume of 2 BV. The P-PNF recovery was 84.32%, and purity increased from 33.80% to 61.70%. Additionally, P-PNF showed increased antioxidant activity compared to PNF. Cumulatively, this study obtained the optimal values for the process parameters in order to achieve the maximum rates of extraction of PNF for economically optimal production at an industrial scale.

Nanonutraceuticals: The New Frontier of Supplementary Food

In the last few decades, the combination between nanotechnology and nutraceutics has gained the attention of several research groups. Nutraceuticals are considered as active compounds, abundant in natural products, showing beneficial effects on human health. Unfortunately, the uses, and consequently the health benefits, of many nutraceutical products are limited by their unsuitable chemico-physical features. For example, many nutraceuticals are characterized by low water solubility, low stability and high susceptibility to light and oxygen, poor absorption and potential chemical modifications after their administration. Based on the potential efficacy of nutraceuticals and on their limiting features, nanotechnology could be considered a revolutionary innovation in empowering the beneficial properties of nutraceuticals on human health, thus enhancing their efficacy in several diseases. For this reason, nanotechnology could represent a new frontier in supplementary food. In this review, the most recent nanotechnological approaches are discussed, focusing on their ability to improve the bioavailability of the most common nutraceuticals, providing an overview regarding both the advantages and the possible limitations of the use of several nanodelivery systems. In fact, although the efficacy of smart nanocarriers in improving health benefits deriving from nutraceuticals has been widely demonstrated, the conflicting opinions on the mechanism of action of some nanosystems still reduce their applicability in the therapeutic field.

Antigenotoxic, antiproliferative and antimetastatic properties of a combination of native medicinal plants from Argentina

ETHNOPHARMACOLOGICAL RELEVANCE

Jarilla is the common name of an appreciated group of native plants from the semi-arid region in Argentina (Larrea cuneifolia Cav., Larrea divaricata Cav. and Zuccagnia punctata Cav.) that have been historically consumed to heal respiratory, musculoskeletal and skin ailments, as well as recommended for weakness/tiredness, hypertension, diabetes and cancer treatment. It was previously reported that some biological properties could be improved when these plants are used jointly. Infusions of a defined mixture, composed by three Jarilla species, L. cuneifolia: L. divaricata: Z. punctata (0.5:0.25:0.25) (HM2) showed synergistic and additive effect on antioxidant activity even after passing through the gastro-duodenal tract.

AIM OF THE STUDY

The main purpose of this work was to evaluate antigenotoxic, antitumor, and anti-metastatic properties of the Jarilla species that grow in the Northwest of Argentina and a herbal combination of them.

MATERIAL AND METHODS

Infusions of Jarilla mixture (HM2), and of each single plant species were prepared. Phenolic profiles of infusions were analyzed by HPLC-ESI-MS/MS and two relevant chemical markers were quantified. The antigenotoxic activity was evaluated by using the Ames test and the Cytokinesis-Block Micronucleus (CBMN) assay against direct mutagens. Evaluations of both cytotoxicity and antiproliferative effects were conducted on tumor and non-tumor cell lines. Both in vivo tumoral growth and metastasis inhibition were evaluated by using a carcinoma model on Balb/c mice.

RESULTS

HM2 mix could suppress genetic and chromosome mutations induced by 4-nitro-o-phenylendiamine (4-NPD) and doxorubicin. Herbal mixture and single plant infusions showed cytotoxic effect against mammary, uterus, and brain tumoral cells without a selective action vs normal human cell line. HM2 mix was able to reduce mammary tumor mass on the Balb/c mice model and showed a significant reduction in the number of metastatic nodules in the lungs.

CONCLUSIONS

Our results suggest that the combinations of three Jarilla species from northwest Argentina would be a promising alternative to treat or slow down the development of chronic diseases, such as cancer.

In Vitro Comparison of the Anti-Proliferative Effects of Galenia africana on Human Skin Cell Lines

Malignant melanoma is the major cause of skin cancer-related deaths. Surgery in combination with radiotherapy, immunotherapy or chemotherapy is used to eradicate cancer cells, however, this treatment option is limited by the tolerance of the surrounding healthy tissue. The extracts from Galenia africana have been shown to possess anti-cancer flavonoid compounds and can be a safer and cost-effective alternative treatment. The study aimed to compare the anti-proliferative effects of G. africana on human skin cells (HaCaT) and human malignant melanoma cells (A375). The cells were exposed to various concentrations of the G. africana extract at different times. In vitro assays were employed to determine cell viability and cytotoxicity. Hoechst 33342 staining was performed to observe the nuclear changes, including apoptosis. G. africana significantly reduced the cell viability of the A375 cells in a dose and time-dependent manner, while having no effect on the HaCaT cells. The A375 cells displayed nuclear condensation, brightly stained nuclei and nuclear fragmentation indicative of apoptosis. This suggests a clinical rationale for the use of G. africana as a potential anti-melanoma agent offering efficacy and low toxicity. This study provides new insights for future work on investigating the utilization of G. africana in malignant melanoma treatment.

Hitting the sweet spot: A systematic review of the bioactivity and health benefits of phenolic glycosides from medicinally used plants

Phenolic acid and flavonoid glycosides form a varied class of naturally occurring compounds, characterised by high polarity-resulting from the glycone moiety-and the presence of multiple phenol functionalities, which often leads to strong antioxidant activity. Phenolic glycosides, and in particular flavonoid glycosides, may possess strong bioactive properties with broad spectrum activity. This systematic literature review provides a detailed overview of 28 studies examining the biological activity of phenolic and flavonoid glycosides from plant sources, highlighting the potential of these compounds as therapeutic agents. The activity of glycosides depends upon the biological activity type, identity of the aglycone and the identity and specific location of the glycone moiety. From studies reporting the activity of both glycosides and their respective aglycones, phenolic glycosides appear to generally be a storage/reserve pool of precursors of more bioactive compounds. The glycosylated compounds are likely to be more bioavailable compared to their aglycone forms, due to the presence of the sugar moieties. Hydrolysis of the glycoside in the in vivo environment would release the free aglycone, potentiating their biological activity. However, further high-quality studies are needed to firmly establish the clinical efficacy of glycosides from many of the plant species studied.

Recent Applications of Heteropolyacids and Related Compounds in Heterocycle Synthesis. Contributions between 2010 and 2020

Over the past two decades, polyoxometalates (POM) have received considerable attention as solid catalysts, due to their unique physicochemical characteristics, since, first, they have very strong Bronsted acidity, approaching the region of a superacid, and second, they are efficient oxidizers that exhibit rapid redox transformations under fairly mild conditions. Their structural mobility is also highlighted, since they are complex molecules that can be modified by changing their structure or the elements that compose them to model their size, charge density, redox potentials, acidity, and solubility. Finally, they can be used in substoichiometric amounts and reused without an appreciable loss of catalytic activity, all of which postulate them as versatile, economic and ecological catalysts. Therefore, in 2009, we wrote a review article highlighting the great variety of organic reactions, mainly in the area of the synthesis of bioactive heterocycles in which they can be used, and this new review completes that article with the contributions made in the same area for the period 2010 to 2020. The synthesized heterocycles to be covered include pyrimidines, pyridines, pyrroles, indoles, chromenes, xanthenes, pyrans, azlactones, azoles, diazines, azepines, flavones, and formylchromones, among others.

Phenolic Acid Derivatives, Flavonoids and Other Bioactive Compounds from the Leaves of Cardiocrinum cordatum (Thunb.) Makino (Liliaceae)

Cardiocrinum cordatum (Thunb.) Makino (Family: Liliaceae), commonly known as ‘Ubayuri’, is native to Japan and some islands in the Russian Far East. It has high value as food, medicinal, and ornamental species. The aim of this study was to isolate and characterize the main chemical constituents of the leaves of C. cordatum. A total of 19 compounds, namely caffeic acid (1), caffeic acid methyl ester (2), caffeic acid β-glucopyranosyl ester (3), caffeic acid 4-O-β-glucopyranoside (4), ferulic acid (5), isoferulic acid (6), protocatechuic acid (7), syringic acid (8), 2,6-dimethoxy-p-hydroquinone 1-O-β-glucopyranoside (9), esculetin (10), taxifolin (11), quercetin 3-O-(6-O-α-rhamnopyranosyl)β-glucopyranoside-7-O-β-rhamnopyranoside (12), 2,7-dimethyl-2,4-diene-deca-α,ω-diacid β-glucopyranoside (13), 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (14), (3Z)-3-hexenyl β-glucopyranoside (15), tryptophan (16), adenine (17), adenosine (18), and 2-deoxyadenosine (19) were isolated using various chromatographic methods. The structures of isolated compounds were elucidated on the basis of their NMR spectroscopic data. All these compounds were isolated for the first time from the genus Cardiocrinum. Phenolic acid derivatives and flavonoids can be considered as chemotaxonomic markers in the leaves of Cardiocrinum species.

Synthesis, characterization and cytotoxicity studies of Co(III)-flavonolato complexes

Hypoxia activated Co(III) complexes as prodrugs may provide with a selective delivery of cytotoxic or antibacterial compounds. Whithin this field sixteen novel Co(III) ternary complexes with the general formula [Co(4N)(flav)](ClO₄)₂, where 4N = tris(2-aminoethyl)amine (tren) or tris(2-pyridylmethyl)amine (tpa) and flav = deprotonated form of differently substituted flavonols have been synthesized, characterized, and their cytotoxicity assayed under both normoxic and hypoxic conditions. Molecular structures of two free flavonols and seven complexes are also reported. In all the complexes the bioligands exhibited the expected (O,O) coordination mode and the complexes showed a slightly distorted octahedral geometry. Cyclic voltammetric studies revealed that both the substituents of the flavonoles and the type of 4N donor ligands had an impact on the reduction potential of the complex. The ones containing tren demonstrated significantly higher stability than the tpa analogues, making these former compounds promising candidates for the development of hypoxia-activated prodrug complexes. Tpa complexes showed higher activity against both selected human cancer cell lines (A549, A431) than their free ligand flavonols, indicating that the anticancer activity of the bioligand can be enhanced upon complexation. However, slight hypoxia-selectivity was found only for a tren complex (11) with moderate cytotoxicity.

An HPLC-DAD Method to Quantify Flavonoids in Sonchus arvensis and Able to Classify the Plant Parts and Their Geographical Area through Principal Component Analysis

A simple and efficient method has been developed for the simultaneous determination of eight flavonoids (orientin, hyperoside, rutin, myricetin, luteolin, quercetin, kaempferol, and apigenin) in Sonchus arvensis by high-performance liquid chromatography diode array detector (HPLC-DAD). This method was utilized to differentiate S. arvensis samples based on the plant parts (leaves, stems, and roots) and the plant’s geographical origin. The chromatographic separation was carried out on a reverse-phase C18 column by eluting at a flow rate of 1 mL/min using a gradient with methanol and 0.2% aqueous formic acid. In the optimum conditions, the developed method’s system suitability has met the criteria of good separation. The calibration curve shows a linear relationship between the peak area and analyte concentration with a correlation coefficient (r2) > 0.9990. The ranges for the analytes’ limits of detection and quantitation were 0.006–0.015 and 0.020–0.052 µg/mL, respectively. Intra-day and inter-day precision expressed in terms of RSD values were <2%, and the accuracy range based on recovery was 97–105%. The stability of all analytes within 48 h was about 2%. By combining HPLC-DAD fingerprint analysis with chemometrics, the developed method can classify S. arvensis samples based on the plant parts and geographical origin.

An environmentally friendly and novel amine-based liquid phase microextraction of quercetin in food samples prior to its determination by UV-vis spectrophotometry

A novel and environmentally-friendly method, which includes determination of trace amounts of quercetin in samples by using UV-vis spectrophotometry after enrichment with amine-based liquid phase microextraction (LPME), has been developed. As extraction solvent, N,N-dimethyl-n-octylamine has been used and the quercetin concentration in extraction phase was determined by UV-vis spectrophotometry at 382.5 nm. Important analytical parameters such as pH, extraction solvent type and volume, sample volume, extraction time were optimized by the method. Quercetin in the sample solution was extracted to 200 μL of N,N-dimethyl-n-octylamine phase at pH 4.0. The detection limit (LOD) and the quantitation limit (LOQ) values for quercetin were calculated as 0.07 μg·mL^-1 and 0.24 μg·mL^-1, respectively. Accuracy studies for the food samples was carried out by addition and recovery experiments. The developed method has been successfully applied to different food samples including spinach, green pepper, red onion and dill weed.

The Flavonol Isoquercitrin Promotes Mitochondrial-Dependent Apoptosis in SK-Mel-2 Melanoma Cell via the PI3K/AKT/mTOR Pathway

Isoquercitrin (IQ), a major flavonol present in Prunus mume fruit, has gained much attention in recent studies because of its superior bioavailability and physiological effects. In this study, the anti-cancer mechanism of IQ against human melanoma, particularly its effect on the mitochondria-mediated apoptosis, was investigated. Treatment with IQ at 25 μM concentration effectively inhibited the proliferation of SK-MEL-2 skin cancer cells while the same concentration did not exhibit cytotoxicity against human keratinocytes HaCaT. Morphological analysis and clonogenic assay also showed that IQ can alter the growth and long-term survival of SK-MEL-2 cells. IQ also induced apoptosis in the melanoma cells as manifested in the nuclear morphology changes, DNA fragmentation, increase in the apoptosis rate (17.69% at 25 μM) and accumulation of sub-G1 cell cycle phase population (19.55% at 25 μM). Western blot analysis revealed the involvement of the mitochondrial apoptosis signaling pathway in the anti-cancer property of IQ. Treatment with IQ resulted in the decrease in the levels of procaspase-8 and -9, and Bcl-2 protein, and an increase in the expression of cleaved PARP and Bax. Moreover, AIF and Endo G protein expression increased, indicating a caspase-independent mitochondrial-mediated apoptosis. The anti-proliferative activity of IQ against SK-MEL-2 can also be attributed to the downregulation of the PI3K/AktmTOR signaling pathway. These findings showed that IQ can be developed into a chemopreventive therapeutic agent against the melanoma cells.

Flavonoids as Multi-Target Compounds: A Special Emphasis on their Potential as Chemo-adjuvants in Cancer Therapy

Flavonoids are low molecular weight, polyphenolic phytochemicals, obtained from secondary metabolism of various plant compounds. They have a spectrum of pharmacological efficacies, including potential anticancer efficacy. Natural flavonoids are present in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. Flavonoids can attenuate or inhibit the initiation, promotion and progression of cancer by modulating various enzymes and receptors in diverse pathways that involve cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis. Furthermore, in vitro, flavonoids have been shown to reverse multidrug resistance when used as chemo-adjuvants. Flavonoids (both natural and synthetic analogues) interact with several oncogenic targets through dependent and independent mechanisms to mediate their anticancer efficacy in different types of cancer cells.

Food chemoprevention and air pollution: the health comes with eating

Ambient air pollution is known to be an important causative agent of many non-communicable diseases, mainly due to fine particulate matter (PM_2.5). According to Global Burden Disease study in 2015, the estimated premature deaths caused by PM_2.5 were 4.2 million. Besides deaths, airborne pollution's effect on human health also has dramatic economic and social costs, contributing greatly to disability-adjusted life-year (DALY). To reduce the health impact is necessary a double approach, which includes the improvement of air quality and food chemoprevention, aimed at enhancing the homeostatic abilities of exposed subjects. The scavenging, antioxidant, and anti-inflammatory properties of nutraceuticals effectively counteract the pathogenic mechanisms common in almost all non-communicable diseases associated with air pollutants. Moreover, several bioactive compounds of food modulate, by epigenetic mechanisms, the metabolism of xenobiotics, favouring conjugation reactions and promoting excretion. This narrative review summarize the numerous pieces of evidence collected in the last decades by observational and experimental studies which underline the chemopreventive role of flavonoids, contained in several fruits and consumer beverages (wine, tea, etc.), and isothiocyanate sulforaphane, contained in the cruciferous vegetables belonging to the genus Brassica. These bioactive compounds, enhancing the individual homeostatic abilities, reduce the harmful effects of airborne pollution.

Plant-Derived Natural Products in Cancer Research: Extraction, Mechanism of Action, and Drug Formulation

Cancer is one of the main causes of death globally and considered as a major challenge for the public health system. The high toxicity and the lack of selectivity of conventional anticancer therapies make the search for alternative treatments a priority. In this review, we describe the main plant-derived natural products used as anticancer agents. Natural sources, extraction methods, anticancer mechanisms, clinical studies, and pharmaceutical formulation are discussed in this review. Studies covered by this review should provide a solid foundation for researchers and physicians to enhance basic and clinical research on developing alternative anticancer therapies.

Adsorption of Anthocyanins by Cation and Anion Exchange Resins with Aromatic and Aliphatic Polymer Matrices

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2-4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8-2.5 compared to the adsorption caused by the π-π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.

Antiangiogenic Activity of Flavonoids: A Systematic Review and Meta-Analysis

Abstract: An imbalance of angiogenesis contributes to many pathologies such as cancer, arthritis and retinopathy, hence molecules that can modulate angiogenesis are of considerable therapeutic importance. Despite many reports on the promising antiangiogenic properties of naturally occurring flavonoids, no flavonoids have progressed to the clinic for this application. This systematic review and meta-analysis therefore evaluates the antiangiogenic activities of a wide range of flavonoids and is presented in two sections. The first part of the study (Systematic overview) included 402 articles identified by searching articles published before May 2020 using ScienceDirect, PubMed and Web of Science databases. From this initial search, different classes of flavonoids with antiangiogenic activities, related pathologies and use of in vitro and/or in/ex vivo angiogenesis assays were identified. In the second part (Meta-analysis), 25 studies concerning the antiangiogenic evaluation of flavonoids using the in vivo chick chorioallantoic membrane (CAM) assay were included, following a targeted search on articles published prior to June 2020. Meta-analysis of 15 out of the 25 eligible studies showed concentration dependent antiangiogenic activity of six compared subclasses of flavonoids with isoflavones, flavonols and flavones being the most active (64 to 80% reduction of blood vessels at 100 µM). Furthermore, the key structural features required for the antiangiogenic activity of flavonoids were derived from the pooled data in a structure activity relationship (SAR) study. All in all, flavonoids are promising candidates for the development of antiangiogenic agents, however further investigations are needed to determine the key structural features responsible for their activity.

Preventative and Therapeutic Potential of Flavonoids in Peptic Ulcers

Peptic ulcer disease is a common gastrointestinal tract disorder that affects up to 20% of the population of the world. Treatment of peptic ulcer remains challenging due to the limited effectiveness and severe side effects of the currently available drugs. Hence, natural compounds, owing to their medicinal, ecological, and other safe properties, are becoming popular potential candidates in preventing and treating peptic ulcers. Flavonoids, the most abundant polyphenols in plants, exhibit gastroprotective effects against peptic ulcer both in vivo and in vitro. In this review, we summarized the anti-ulcer functions and mechanisms, and also the bioavailability, efficacy, and safety, of flavonoid monomers in the gastrointestinal tract. Flavonoids exerted cytoprotective and rehabilitative effects by not only strengthening defense factors, such as mucus and prostaglandins, but also protecting against potentially harmful factors via their antioxidative, anti-inflammatory, and antibacterial activities. Although controlled clinical studies are limited at present, flavonoids have shown a promising preventable and therapeutic potential in peptic ulcers.

Sulfated Metabolites of Luteolin, Myricetin, and Ampelopsin: Chemoenzymatic Preparation and Biophysical Properties

Authentic standards of food flavonoids are important for human metabolic studies. Their isolation from biological materials is impracticable; however, they can be prepared in vitro. Twelve sulfated metabolites of luteolin, myricetin, and ampelopsin were obtained with arylsulfotransferase from Desulfitobacterium hafniense and fully characterized by high-performance liquid chromatography, MS, and NMR. The compounds were tested for their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), and N,N-dimethyl-p-phenylenediamine radicals, to reduce ferric ions and Folin-Ciocalteu reagent, and to inhibit tert-butyl hydroperoxide-induced lipid peroxidation of rat liver microsomes. The activity differed considerably even between monosulfate isomers. The parent compounds and myricetin-3'-O-sulfate were the most active while other compounds displayed significantly lower activity, particularly luteolin sulfates. No mutagenic activity of the parent compounds and their main metabolites was observed; only myricetin showed minor pro-mutagenicity. The prepared sulfated metabolites are now available as authentic standards for future in vitro and in vivo metabolic studies.

Entomopathogenic Filamentous Fungi as Biocatalysts in Glycosylation of Methylflavonoids

Flavonoids are known for their numerous biological activities; however, their pharmacological application is limited by poor bioavailability. Glycosides are usually more stable and more soluble in water and in this form, flavonoids are present in nature. Likewise, the presence of the methyl group in the flavonoid skeleton results in facilitated absorption and greater bioavailability. Entomopathogenic filamentous fungi are effective in the biotransformation of flavonoids; they are known especially for efficient glycosylation. In the current study we used strains of Beauveria bassiana KCH J1.5 and Isaria fumosorosea KCH J2 to biotransform flavonoids with a single methyl group. 2′-Hydroxy-5′-methylchalcone was biotransformed by both strains into 2′-hydroxy-5′-methylchalcone 3-O-β-D-(4″-O-methyl)-glucopyranoside. In the culture of B. bassiana KCH J1.5 four products were obtained from 6-methylflavanone: 4′-hydroxy-6-methylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside; 4′-hydroxyflavanone 6-methylene-O-β-D-(4″-O-methyl)-glucopyranoside; 6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside and 4′-hydroxy-6-hydroxymethylflavanone 3′-O-β-D-(4″-O-methyl)-glucopyranoside. Biotransformation with I. fumosorosea KCH J2 as a biocatalyst resulted in the formation of 6-methylflavanone 4′-O-β-D-(4″-O-methyl)-glucopyranoside and 2-phenyl-6-methylchromane 4-O-β-D-(4″-O-methyl)-glucopyranoside. All of these flavonoids can be used in biological activity tests and can be useful in studies concerning structure—bioactivity relationships.

The evaluation of hepatoprotective effects of flavonoids from Scorzonera austriaca Wild against CCl4-induced acute liver injury in vitro and in vivo

Scorzonera austriaca Wild is a traditional herbal medicine; however, little is known with regard to the effect of flavonoids from S. austriaca (FSA) on liver injury induced by Carbon tetrachloride (CCl₄), especially the mechanism remains unknown. Therefore, our paper was designed to investigate the hepatoprotective effect of FSA against CCl₄-induced acute liver injury in vitro and in vivo, with focus on its potential mechanism. The purity of FSA prepared by using polyporous resin column chromatography could reach 94.5%, and seven flavonoid compounds in FSA were identified by using LC-ESI-MS analysis. In vivo results showed that FSA markedly decreased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and malonaldehyde (MDA) and increased the contents of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Furthermore, in vivo and in vitro results confirmed that FSA could inhibit inflammatory response, as evidenced by decreasing the levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) through inactivating toll-like receptor-4/nuclear factor-κB (TLR4/NF-κB) signaling pathway. FSA activated autophagy by increasing the ratio of LC3B-II/I and decreasing the protein level of p62 so as to exert its hepatoprotective effect. In general, these evidences suggested that FSA is likely to serve as a potential material for the drugs against chemical hepatic injury.

The Citrus Flavanone Hesperetin Induces Apoptosis in CTCL Cells via STAT3/Notch1/NFκB-Mediated Signaling Axis

Background:

Hesperetin is a natural compound known for its cholesterol-lowering effect and a wide range of pharmacological activities.

Objectives:

Investigating the potential anticancer activities of Hesperetin in malignant hematolymphoid cell lines HuT78 and MJ, derived from patients with Cutaneous T-Cell Lymphomas (CTCL).

Methods:

The cytotoxic effect of Hesperetin on two different CTCL cell lines, HuT78 and MJ, was assessed by MTS-based colorimetric assay. Apoptosis, cell cycle, ROS (Reactive Oxygen Species) and molecular analysis were performed using flow-cytometry and immunoblotting.

Results:

Hesperetin-treated CTCL cells were arrested at the sub-G1 phase of cell cycle with the concomitant decrease in the expression of the cell cycle regulator protein cyclin B. In addition, the study found that the cellular treatment with Hesperetin caused an induction of apoptosis, which was independent of ROS generation. Hesperetin caused a significant decrease in the expression level of anti-apoptotic protein Bcl-xL and an increase in cleaved caspase-3 and PARP proteins in CTCL cells. Furthermore, Hesperetin treatment in CTCL cells down-regulated the expression of Notch1 and phosphorylation of STAT3 (Tyr705) and inhibited NFκBp65.

Conclusion:

This study highlights the anticancer properties of Hesperetin. Which induces apoptosis in CTCL cells via STAT3/Notch1/NFκB mediated signaling pathway, suggesting that further development of this novel class of flavonoid may contribute to new drug discovery for certain hematolymphoid malignancies.

Asiaticoside Antagonizes Proliferation and Chemotherapeutic Drug Resistance in Hepatocellular Carcinoma (HCC) Cells

Background

Hepatocellular carcinoma (HCC) is the fifth most prevalent malignant tumor in China after lung cancer, gastric cancer, esophageal cancer, and breast cancer, and has a high mortality rate. Though there are a series of therapeutic strategies is now available for HCC in clinical practice, the 5-year survival rate after surgery is still low. In addition, multi-drug resistance (MDR) is one of the most important factors responsible for the low survival rate and poor therapy response in HCC. Hence, novel treatment strategies and molecules for HCC need to be developed.

Material/Methods

We assessed the effect of asiaticoside, a natural product derived from Centella asiatica (L.) Urban, on HCC cell proliferation and drug resistance.

Results

Our data indicated that asiaticoside significantly inhibited the proliferation of HCC cell lines QGY-7703 and Bel-7402 in a dose- and time-dependent manner. Moreover, asiaticoside significantly induced apoptosis in QGY-7703 and Bel-7402 cells. Treatment with asiaticoside also caused G1 cell cycle arrest in QGY-7703 and Bel-7402 cells. Western blot assay results indicated that the mechanism underlying the effects of asiaticoside involves inhibiting the activity of the PI3K/Akt and MAPK/ERK pathways. Furthermore, asiaticoside significantly antagonized P-gp-mediated MDR in HCC cells.

Conclusions

Our results suggest that asiaticoside has the potential to be applied in the treatment of HCC patients, but further evidence is needed to confirm our results, particularly in vivo efficacy.

Evaluation of General Synthesis Procedures for Bioflavonoid-Metal Complexes in Air-Saturated Alkaline Solutions

The general synthesis methods of bioflavonoid-metal complexes are considered to be unreliable due to the instability of flavonoids in air-saturated alkaline solutions. In this study, dihydromyricetin (DHM), as a representative bioflavonoid, was selected for complexation with various transition metal ions in an air-saturated alkaline solution to form DHM-metal(II) complexes, following the general synthetic procedure. After characterization, the metal complexes were hydrolyzed to observe the stability of DHM under acidic conditions via HPLC. The effects of synthetic conditions (metal ion, alkalinity, and reflux time) on DHM stability were then investigated by UV-vis spectroscopy and HPLC. Finally, using electron paramagnetic resonance, DHM and its analogs were observed with DMPO (5,5-dimethyl-1-pyrroline-N-oxide) to form a relatively stable free radical adduct. Multiple peaks corresponding to unknown compounds appeared in the LC spectra of the DHM-metal(II) complexes after hydrolysis, indicating that some DHM reacted during synthesis. Subsequently, the transition metal ion and solution alkalinity were found to have notable effects on the stability of free DHM. Furthermore, DHM and several of its analogs generated the superoxide-anion radical in air-saturated alkaline solutions. Their capacities for generating the superoxide anion seemed to correspond to the number and/or location of hydroxyl groups or their configurations. Interestingly, DHM can react with the superoxide anion to transform into myricetin, which involves the abstraction of a C3-H atom from DHM by O₂ ^-. Therefore, the general synthetic procedure for bioflavonoid-metal complexes in air-saturated alkaline solutions should be improved.

Results in Chemistry of Natural Organic Compounds. Synthesis of New Anticancer Vinca Alkaloids and Flavone Alkaloids

The antitumor indole–indoline alkaloids of the evergreen Catharanthus roseus—namely vinblastine and vincristine—are widely used in chemotherapy of cancer. Many efforts were made to synthesize more efficient derivatives with less side-effect. The 14,15-cyclopropane derivative of vinblastine was synthesized successfully by a five-step procedure starting from vindoline. Vincristine, vinorelbine and several derivatives condensed with a cyclopropane ring were synthesized. Various hybrid molecules were prepared by the coupling reaction of vindoline and methyl ester of tryptophan, which were conjugated by carrier peptides of octaarginine. Studying the halogenation reactions of vindoline and catharanthine some fluorine derivatives were obtained which showed promising antitumor activity on various tumor types. The synthesis of the Aspidospermane alkaloid bannucine and 5′-epibannucine were carried out using N-acyliminium intermediates. The same intermediate was also applied in the first synthesis of sessiline. The research group have synthesized of flavonoid alkaloids: dracocephins A and B. Further three flavonoid alkaloids, namely 8-(2”-pyrrolidinon-5′′-yl)quercetin, 6-(2′′-pyrrolidinon-5′′-yl)-(−)- and 8-(2′′-pyrrolidinon-5′′-yl)-(−)-epicatechin were prepared by acid-catalyzed regioselective Mannich reaction starting from the corresponding flavonoid precursor. Vindoline was also coupled to synthetic pharmacophores, such as triphenylphosphine and various N-heterocycles. Some of these hybrid molecules showed significant antitumor activity. Furthermore, 7-OH and 7-NH modified flavonoid derivatives were synthesized by a regioselective alkylation followed by Smiles rearrangement and hydrolysis.

Associations between serum concentration of flavonoids and breast cancer risk among Chinese women

PURPOSE

In vitro and in vivo studies suggested that flavonols, flavones, flavanones and flavan-3-ols have preventive effects on breast carcinogenesis. Epidemiological evidence about the associations between these flavonoid biomarkers and breast cancer risk is limited. This study aimed to investigate the association between serum concentration of these flavonoids and breast cancer risk among Chinese women.

METHODS

This hospital-based case-control study recruited 792 breast cancer cases and 813 age frequency-matched (5-year interval) controls who provided eligible blood samples in Guangdong Province, China. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure flavonoids. Unconditional logistic regression was used to estimate the odds ratio (OR) and 95% confidence internal (CI).

RESULTS

Higher concentrations of serum flavonols, isorhamnetin, kaempferol, flavanones and naringenin were significantly associated with lower breast cancer risk, with adjusted ORs (95% CIs) for the highest versus the lowest group of 0.66 (0.49-0.89) for flavonols, 0.52 (0.38-0.70) for isorhamnetin, 0.60 (0.45-0.80) for kaempferol, 0.65 (0.49-0.87) for flavanones and 0.45 (0.34-0.60) for naringenin, respectively. Significant positive associations were observed between serum flavan-3-ols, epigallocatechin, epigallocatechin-3-gallate and breast cancer risk. No significant associations were observed for serum quercetin, flavones, apigenin, luteolin, hesperetin, catechin, epicatechin and epicatechin-3-gallate with overall breast cancer risk.

CONCLUSIONS

This study suggested that serum flavonols and flavanones were inversely associated with breast cancer risk and serum flavan-3-ols were positively associated with breast cancer risk. Serum flavones were not associated with overall breast cancer risk. These findings warrant further confirmation in prospective studies.

Chemical Fingerprinting, Isolation and Characterization of Polyphenol Compounds from Heliotropium taltalense (Phil.) I.M. Johnst and Its Endothelium-Dependent Vascular Relaxation Effect in Rat Aorta

Heliotropium taltalense is an endemic species of the northern coast of Chile and is used as folk medicine. The polyphenolic composition of the methanolic and aqueous extract of the endemic Chilean species was investigated using Ultrahigh-Performance Liquid Chromatography, Heated Electrospray Ionization and Mass Spectrometry (UHPLC-Orbitrap-HESI-MS). Fifty-three compounds were detected, mainly derivatives of benzoic acid, flavonoids, and some phenolic acids. Furthermore, five major compounds were isolated by column chromatography from the extract, including four flavonoids and one geranyl benzoic acid derivative, which showed vascular relaxation and were in part responsible for the activity of the extracts. Since aqueous extract of H. taltalense (83% ± 9%, 100 μg/mL) produced vascular relaxation through an endothelium-dependent mechanism in rat aorta, and the compounds rhamnocitrin (89% ± 7%; 10⁻⁴ M) and sakuranetin (80% ± 6%; 10⁻⁴ M) also caused vascular relaxation similar to the extracts of H. taltalense, these pure compounds are, to some extent, responsible for the vascular relaxation.

FB-15 inhibits MGC-803 cells growth by regulating energy metabolism

In this study, we scrutinized the anticancer effects of FB-15 on human gastric carcinoma MGC-803 cells in vitro and vivo, and its preliminary effect on tubulin and HIF-1α. We confirmed that FB-15 not only inhibited the proliferation of a large number of cells in a concentration and time-dependent manner but also inhibited proliferation of a single cell to form clones. FB-15 manifested little cytotoxicity for normal stomach cells GES-1. The flow cytometry analysis displayed that FB-15 induced apoptosis MGC-803 cells and mainly arrested cells in the S phase in a concentration-dependent manner. The results of the wound healing assay indicated that FB-15 suppressed cell migration. Furthermore, the western blotting showed that FB-15 down-regulated the expression of β3-tubulin and HIF-1α, consistent with Immunohistochemical assay. The binding modes of FB-15 with tubulin were clarified by molecular docking. FB-15 significantly suppressed the growth of MGC-803 gastric cancer tumors. The inhibitory effect of FB-15 on tumor growth was superior to 5-Fu. Taken together, these results provided evidence for FB-15 to be used as an effective anticancer drug candidate for gastric cancer.

In Silico Identification of Type III PKS Chalcone and Stilbene Synthase Homologs in Marine Photosynthetic Organisms

Marine microalgae are photosynthetic microorganisms at the base of the marine food webs. They are characterized by huge taxonomic and metabolic diversity and several species have been shown to have bioactivities useful for the treatment of human pathologies. However, the compounds and the metabolic pathways responsible for bioactive compound synthesis are often still unknown. In this study, we aimed at analysing the microalgal transcriptomes available in the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP) database for an in silico search of polyketide synthase type III homologs and, in particular, chalcone synthase (CHS) and stilbene synthase (STS), which are often referred to as the CHS/STS family. These enzymes were selected because they are known to produce compounds with biological properties useful for human health, such as cancer chemopreventive, anti-inflammatory, antioxidant, anti-angiogenic, anti-viral and anti-diabetic. In addition, we also searched for 4-Coumarate: CoA ligase, an upstream enzyme in the synthesis of chalcones and stilbenes. This study reports for the first time the occurrence of these enzymes in specific microalgal taxa, confirming the importance for microalgae of these pathways and giving new insights into microalgal physiology and possible biotechnological applications for the production of bioactive compounds.

Apigetrin induces extrinsic apoptosis, autophagy and G2/M phase cell cycle arrest through PI3K/AKT/mTOR pathway in AGS human gastric cancer cell

Apigetrin is a flavonoid glycoside phytonutrient derived from fruits and vegetables that is well known for a variety of biological activities such as antioxidant and anti-inflammatory activities. In the current study, we determined the effect of apigetrin on AGS gastric cancer cell. Apigetrin reduced cancer cell proliferation and induced G2/M phase cell cycle arrest by regulating cyclin B1, cdc25c and cdk1 protein expression in AGS cell. Apigetrin treatment caused apoptotic cell death in AGS cells, characterized by the accumulation of apoptosis portion, cleavage of caspase-3 and poly ADP-ribose polymerase (PARP). Apigetrin-treated cells increased the expression of extrinsic apoptosis pathway proteins and mRNA. However, intrinsic apoptosis pathway related proteins were not altered. In addition, AGS cells treated with apigetrin increased autophagic cell death, featured by the formation of autophagic vacuole and acidic vesicular organelles. Autophagy marker proteins, such as LC3B-II and beclin-1, were increased, and p62, an autophagy flux marker protein, was also increased by endoplasmic reticulum stress. Also, the phosphorylation of PI3K/AKT/mTOR pathway proteins and its downstream targets in apigetrin-treated AGS cells was identified to be decreased. Taken together, these data suggest that apigetrin-treated AGS cells induced G2/M phase cell cycle arrest, extrinsic apoptosis and autophagic cell death through PI3K/AKT/mTOR pathway, which can lead to the inhibition of gastric cancer development. Thus, our findings strongly indicate that apigetrin is a basic natural derived compound that could be used as a nutrient source with potential anticancer activities against gastric cancer.

Involvement of heme oxygenase-1 in suppression of T cell activation by quercetin

AIM

Acute rejection is still a major problem in transplantation and one of the most important causes of late graft loss. Cyclosporine and tacrolimus are widely used for suppression of T cell function to avoid graft rejection, but long-term use of these compounds is associated with serious toxicities. Quercetin, a flavonoid found in fruits and vegetables, has been demonstrated to exhibit cytoprotective effects through the induction of heme oxygenase (HO) -1, an enzyme involved in heme catabolism. We hypothesized that quercetin induces HO-1 in T cells and suppresses T cell function via HO-1. In the present study, we showed that quercetin suppressed the A23187-mediated expression of interleukin (IL) -2 in T cells.

METHODS

Mouse splenocytes, enriched T cells, and EL4 cells, a mouse T cell line, were treated with quercetin, and then stimulated with A23187, a calcium ionophore, concanavalin A, or anti-CD3ε and anti-CD28 antibodies. Cell proliferation, expression of IL-2, calcium mobilization, apoptosis, cell cycle, and phosphorylation of extracellular signal-regulated kinase (ERK) were investigated.

RESULTS

Quercetin induced HO-1, and this induction of HO-1 was implicated in the suppression of IL-2 production. Furthermore, the induction of HO-1 by quercetin suppressed the influx of calcium ions, a known trigger of IL-2 production. Additionally, quercetin suppressed T cell proliferation through promotion of cell cycle arrest via HO-1 induction, but quercetin did not induce apoptosis. To investigate the role of the signal transduction pathway in quercetin's effect on cell proliferation, we evaluated the phosphorylation of ERK in T cells. Quercetin suppressed the A23187-mediated stimulation of ERK, an effect that was mediated through HO-1. These results suggested that HO-1 is involved in the suppressive effects of quercetin on T cell activation and proliferation.

CONCLUSION

Our findings indicate that the quercetin may be a promising candidate for inducing HO-1 in T cells, thereby facilitating immunosuppressive effects.

ASTILBIN: A PROMISING UNEXPLORED COMPOUND WITH MULTIDIMENSIONAL MEDICINAL AND HEALTH BENEFITS

BACKGROUND

Many flavonoids have various beneficial actions like anti-inflammatory, anti-carcinogenic properties and many other clinical conditions. Astilbin is one such flavanoid compound having many physiological as well as pharmacological actions.

PURPOSE

To summarize the important findings from the research conducted using astilbin having significance to its physiological and pharmacological activities as well as the patents filed using astilbin.

STUDY DESIGN

Systematic review and compilation of the collected literature.

METHOD

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct and Google Scholar etc. All the article available in the English language that used our compound of interest i.e. astilbin, on the basis of inclusion criteria decided were retrieved from these databases, thoroughly reviewed and were summarized.

RESULT

It has been established that astilbin can play a vital in the management of diseases associated with immune system. It also possesses antibacterial, anti-oxidative and hepatoprotective activity.

CONCLUSION

These researches provide evidence that astilbin possesses great potential and thus can be utilized in the management of various disorders, thus establishing itself as a potential candidate for novel drug development. Also, there is still room for research on astilbin like it can be evaluated for anticancer potential, protective effect in various diabetic complications and many more. Overall observations from data suggested that astilbin is a promising compound and proved its efficacy in every preclinical study which is conducted till date. Some of the pharmacological activity is still unexplored. After successful preclinical trials, astilbin can go for further clinical trials.

Polymethoxyflavones from Gardenia oudiepe (Rubiaceae) induce cytoskeleton disruption-mediated apoptosis and sensitize BRAF-mutated melanoma cells to chemotherapy

A series of 10 natural and semisynthetic flavonoids (1 to 10) were obtained from Gardenia oudiepe (Rubiaceae), an endemic plant from New Caledonia. Most of them were polymethoxylated flavones (PMFs) of rare occurrence. After a cell viability screening test, PMFs 2 and 3 showed significant cytotoxic activity against A2058 human melanoma cells (IC₅₀ = 3.92 and 8.18 μM, respectively) and were selected for in-depth pharmacological assays. Both compounds inhibited cell migration and induced apoptosis and cell cycle arrest after 72h of treatment. Immunofluorescence assays indicated that these outcomes were possibly related to the induction of cytoskeleton disruption associated to actin and tubulin depolymerization. These data were confirmed by molecular docking studies, which showed a good interaction between PMFs 2 and 3 and tubulin, particularly at the colchicine binding site. As A2058 are considered as chemoresistant to conventional chemotherapy, compounds 2 and 3 (½IC₅₀) were associated to clinically-used antimelanoma drugs (vemurafenib and dacarbazine) and combined therapies efficacy was assessed by the MTT assay. PMFs 2 restored the sensitivity of A2058 cells to dacarbazine treatment (IC₅₀ = 49.38 μM vs. >100 μM). Taken together, these data suggest that PMFs from G. oudiepe could be potential leaders for the design of new antimelanoma drugs.

Investigation of the interactions between flavonoids and human organic anion transporting polypeptide 1B1 using fluorescent substrate and 3D-QSAR analysis

Organic anion transporting polypeptide 1B1 (OATP1B1) is a key hepatic uptake transporter whose inhibition could lead to adverse drug-drug and drug-food interactions. Flavonoids are widely distributed in food and beverages and thus our bodies are frequently exposed to them. Therefore, investigation of the interactions between OATP1B1 and flavonoids could be of great significance. In the present study, 25 common flavonoids were investigated for their interactions with OATP1B1 using the fluorescent substrate 2',7'-dichlorofluorescein (DCF) and three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis. Kinetic study showed that OATP1B1-mediated DCF uptake exhibited a monophasic saturation kinetics with a K_m value of 9.7 ± 2.4 μM. Inhibition assay for flavonoids on OATP1B1-mediated DCF uptake was performed and their IC₅₀ values were determined upon which reliable and predictive CoMFA (q² = 0.604, r² = 0.841) and CoMSIA (q² = 0.534, r² = 0.807) models were developed. Our experimental and computational results showed that flavonoid aglycones interacted with OATP1B1 much stronger than their glycosides such as 3-O- and 7-O-glycosides as bulky hydrophilic and hydrogen-bond forming substituents at C-3 and C-7 positions on rings A and C were unfavorable for their binding. On the other hand, the presence of hydrogen-bond forming groups on ring B was beneficial as long as the number of hydroxyl groups was not >2. Our results also indicated that flavones usually interacted with OATP1B1 much stronger than their 3-hydroxyflavone counterparts (flavonols). The obtained information and 3D-QSAR models could be useful for elucidating and predicting the interactions between flavonoids and human OATP1B1.

Synthesis and antiproliferative activities of polymethoxyflavones aminoalkyl and amino acid derivatives

Twelve novel aminoalkyl derivatives 3a-3f, 4a-4f and four novel amino acid derivatives 5a, 5b, 6a and 6b of polymethoxyflavones 1 and 2 were synthesized through regioselective demethylation, etherification, amination, EDCl-mediated amide condensation and alkaline hydrolysis, using tangeretin and nobiletin as starting materials. Their antiproliferative activities against four different human cancer cell lines (Aspc-1, SUN5, HepG-2 and HCT116) were evaluated by in vitro CCK-8 assay. The results show that the majority of the synthetic compounds exhibited moderate to good antiproliferative activity. In particular, the antiproliferative activity of compound 5b against HepG-2 cells (IC50 0.057 μM) was equal to the positive control drug Staurosporine (IC50 0.0575 μM).

Evaluation of apoptotic effects of mPEG-b-PLGA coated iron oxide nanoparticles as a eupatorin carrier on DU-145 and LNCaP human prostate cancer cell lines

Many studies have so far confirmed the efficiency of phytochemicals in the treatment of prostate cancer. Eupatorin, a flavonoid with a wide range of phytomedical activities, suppresses proliferation of and induces apoptosis of multiple cancer cell lines. However, low solubility, poor bioavailability, and rapid degradation limit its efficacy. The aim of our study was to evaluate whether the use of mPEG-b-poly (lactic-co-glycolic) acid (PLGA) coated iron oxide nanoparticles as a carrier could enhance the therapeutic efficacy of eupatorin in DU-145 and LNcaP human prostate cancer cell lines. Nanoparticles were prepared by the co-precipitation method and were fully characterized for morphology, surface charge, particle size, drug loading, encapsulation efficiency and in vitro drug-release profile. The inhibitory effect of nanoparticles on cell viability was evaluated by MTT test. Apoptosis was then determined by Hoechest staining, cell cycle analysis, NO production, annexin/propidium iodide (PI) assay, and Western blotting. The results indicated that eupatorin was successfully entrapped in Fe₃O₄@mPEG-b-PLGA nanoparticles with an efficacy of (90.99 ± 2.1)%. The nanoparticle’s size was around (58.5 ± 4) nm with a negative surface charge [(−34.16 ± 1.3) mV]. In vitro release investigation showed a 30% initial burst release of eupatorin in 24 h, followed by sustained release over 200 h. The MTT assay indicated that eupatorin-loaded Fe₃O₄@mPEG-b-PLGA nanoparticles exhibited a significant decrease in the growth rate of DU-145 and LNcaP cells and their IC50 concentrations were 100 μM and 75 μM, respectively. Next, apoptosis was confirmed by nuclear condensation, enhancement of cell population in the sub-G1 phase and increased NO level. Annexin/PI analysis demonstrated that eupatorin-loaded Fe₃O₄@mPEG-b-PLGA nanoparticles could increase apoptosis and decrease necrosis frequency. Finally, Western blotting analysis confirmed these results and showed that Bax/Bcl-2 ratio and the cleaved caspase-3 level were up-regulated by the designing nanoparticles. Encapsulation of eupatorin in Fe₃O₄@mPEG-b-PLGA nanoparticles increased its anticancer effects in prostate cancer cell lines as compared to free eupatorin. Based on these results, this formulation can provide a sustained eupatorin-delivery system for cancer treatment with the drug remaining active at a significantly lower dose, making it a suitable candidate for pharmacological uses.

•

In the current study, Eupatorin was efficiently encapsulated in mPEG-b-PLGA coated iron oxide nanoparticles.

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The nanoparticles bypass the limitations and provide a sustained release of Eupatorin into the human prostate cancer cell.

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The designed nanoparticles can be more effective in inhibiting cancer cell growth as compared to free form.

Synthesis, Biological Investigation and Docking Study of Novel Chromen Derivatives as Anti-Cancer Agents

BACKGROUND

According to the latest global cancer data, cancer burden rises to 18.1 million new cases and 9.6 million cancer deaths in 2018. Among that female breast cancer ranks as the fifth leading cause of death (627000 deaths, 6.6%). The main causative factor involved in breast cancer development and progression is the Estrogen Receptor (ER) which is the essential target for anti-cancer drug discovery. Since millennia ER-α has been considered as an oncology mark for the treatment of breast cancer.

METHODS

A series of novel 6-methyl-3-(3-oxo-1-phenyl-3-(4-(2-(piperidin-1-yl)ethoxy)phenyl)propyl)-2Hchromen- 2-one was designed, synthesized and screened for their anti-breast cancer activity against estrogen receptor-positive MCF-7, ZR-75-1 and negative MDA-MB-435 human breast cancer cell lines. Estrogen level of all the potent cytotoxic compounds were measured on day 30 of intoxication was compared with the control and N-methyl-N-nitrosourea (MNU) group. The docking study was performed to predict binding orientation towards the estrogen receptor-α.

RESULTS

Among the synthesized compounds C-3, C-5 and C-15 were showing potent cytotoxicity against estrogen receptor-positive MCF-7. The potent cytotoxic compounds C-3, C-5 and C-15 were further evaluated for in vivo anti-cancer activity by MNU induced mammary carcinoma in female sprague-dawley rats. The in vivo anticancer activity result shows that the compound C-5 has protuberant affinity towards estrogen receptor as standard TAM (Tamoxifen). The docking of the synthesized chromen derivatives showed interaction modes comparable to that of the co-crystallized ligands.

CONCLUSION

The designed class has very promising starting point for the development and further improvement in anti-breast cancer class of drugs.

An in vitro study of the effect of carob (Ceratonia siliqua L.) leaf extracts on gilthead seabream (Sparus aurata L.) leucocyte activities. Antioxidant, cytotoxic and bactericidal properties

Carob leaves, the main residues of the carob tree, were investigated as a renewable and abundant source of bioactive compounds for fish aquaculture. Aqueous and ethanolic extracts obtained from carob leaves were characterized in terms of biochemical composition, antiradical and cytotoxic effects and immunostimulant and antibacterial activities. The ethanolic extract showed higher levels of total phenolics, flavonoids and condensed tannins and higher antioxidant activity than the aqueous extract. No significant immunostimulant effects were observed on gilthead seabream (Sparus aurata) head kidney leucocytes (viability, phagocytosis and respiratory burst activities and peroxidase content) after incubation for 24 h with different extracts. Furthermore, the ethanolic extracts used at 0.5, 0.75 and 1 mg mL^-1 and aqueous extracts at 1 g mL^-1 had a cytotoxic effect on PLHC-1 cells. When the bactericidal activity was tested against three fish pathogenic bacteria (Vibrio harveyi, Vibrio anguillarum and Photobacterium damselae) notable activity of the different extracts was detected against P. damselae at all three concentrations. A similar effect was demonstrated against V. haryeri when ethanolic extracts were used in the same range of concentrations. This work demonstrates interesting in vitro effects of carob leaf extracts and suggests it could be used as an alternative to chemical compounds with farmed fish. The concentration and nature of the extracts were very important in terms of any positive results.

DNA-BINDING and DNA-protecting activities of small natural organic molecules and food extracts

The review summarizes literature data on the DNA-binding, DNA-protecting and DNA-damaging activities of a range of natural human endogenous and exogenous compounds. Small natural organic molecules bind DNA in a site-specific mode, by arranging tight touch with the structure of the major and minor grooves, as well as individual bases in the local duplex DNA. Polyphenols are the best-studied exogenous compounds from this point of view. Many of them demonstrate hormetic effects, producing both beneficial and damaging effects. An attempt to establish the dependence of DNA damage or DNA protection on the concentration of the compound turned out to be successful for some polyphenols, daidzein, genistein and resveratrol, which were DNA protecting in low concentrations and DNA damaging in high concentrations. There was no evident dependence on concentration for quercetin and kaempferol. Probably, the DNA-protecting effect is associated with the affinity to DNA. Caffeine and theophylline are DNA binders; at the same time, they favor DNA repair. Although most alkaloids damage DNA, berberine can protect DNA against damage. Among the endogenous compounds, hormones belonging to the amine class, thyroid and steroid hormones appear to bind DNA and produce some DNA damage. Thus, natural compounds continue to reveal beneficial or adverse effects on genome integrity and provide a promising source of therapeutic activities.

Development of a classification model for the antigenotoxic activity of flavonoids

Genotoxic agents are capable of causing damage to genetic material and the cumulative DNA damage causes mutations, involved in the development of various pathological conditions, including cancer. Antigenotoxic agents possess the potential to counteract these detrimental cellular modifications and may aid in preventing, delaying, or decreasing the severity of these pathological conditions. An important class of natural products for which promising antigenotoxic activities have already been shown, are the flavonoids. In this research, we investigated the quantitative structure-activity relationship (QSAR) of flavonoids and their antigenotoxic activity against benzo[a]pyrene (B[a]P) and its mutagenic metabolite B[a]P-7,8-diol-9,10-epoxide-2. Random Forest classification models were developed, which could be useful as a preliminary in silico evaluation tool, before performing in vitro or in vivo experiments. The descriptors G2S and R8s. were the most significant for predicting the antigenotoxic potential.

Engineering Saccharomyces cerevisiae Coculture Platform for the Production of Flavonoids

Flavonoids are valuable natural products widely used in human health and nutrition applications. Engineering microbial consortia to express complex flavonoid biosynthetic pathways is a promising approach for flavonoid production. In this study, the entire flavonoid biosynthetic pathway was split into two independent pathways, each of which was contained in separate Saccharomyces cerevisiae cells. The first cell type, sNAR5, which was genetically engineered to express the naringenin biosynthetic pathway, produced 144.1 mg/L naringenin. The second cell type was genetically modified with the heterologous naringenin-to-delphinidin pathway. A coculture produced a delphinidin titer, significantly higher than that produced in a monoculture of strain sDPD2, harboring the entire pathway. Furthermore, we successfully employed this coculture platform for the production of 3 flavonols and 2 anthocyanidins in flask-scale culture. This coculture platform paves the way for the development of an economical and efficient process for microbial flavonoid production.