Isoflavonoids of the leguminosae

Deracemization of C(sp3)-H Arylated Carbonyl Compounds via Asymmetric Ion-Pairing Photoredox Catalysis

Deracemization of C(sp3)-H arylated carbonyl compounds faces limitations in terms of substrate scope. Through the photoactivation of the aryl group and the stereocontrol of the generated arene radical cation via asymmetric ion-pairing catalysis, we are able to achieve deracemization of carbonyl compounds arylated at both enolizable and unenolizable stereocenters. A diverse range of α-, β-, and γ-aryl ketones and esters, including natural products and medicinal derivatives, can be effectively converted into their enantiomers with high enantioselectivity. Mechanistic investigations through combined experimental and computational studies suggest that the reaction involves single-electron oxidation of electron-rich aryl groups, followed by a kinetic resolution of the resulting radical cation intermediates by the chiral phosphate anion. Deprotonation is identified as the stereodetermining step, while stereoselective back electron transfer and triplet-state quenching of 3 Mes-Acr1+* may also affect the enantioselectivity at the photostationary state.

Target Isolation of Prenylated Isoflavonoids and Pterocarpans from Acosmium diffusissimum Using LC-MS/MS-Based Molecular Networking

This is the report of the HPLC-MSn-guided isolation of new anti-inflammatory prenylated isoflavonoids and pterocarpans from the stems of Acosmium diffusissimum using GNPS molecular networking as the main tool. Cluster analysis guided the isolation of five new prenylated isoflavonoids, diffusiflavone A-E (1-4 and 9), two prenylated pterocarpans, diffusicarpan A and B (5 and 6), and two known compounds 6-prenylorobol (7) and 3-O-methylquercetin (8). The in vitro anti-inflammatory potential of compounds 1-6 and 9 was assessed in macrophages induced with lipopolysaccharide (LPS). Compounds 2, 3, 5, and 9 were observed to have a reduction in NO levels in at least one of the concentrations tested (1.25, 2.5, 5, 10, and 20 μg/mL) and also reduced IL-1β and IL-6 cytokines, especially diffusicarpan A which reduced cytokine levels in all the concentrations tested.

N-Heterocyclic Carbene Organocatalysis Enabled Modular Synthesis of Fluorinated Isoflavonoids to Suppress Proliferation and Migration in Breast Cancer Cells

Isoflavonoids represent a privileged scaffold among various bioactive natural products, rendering their structural diversification through green synthesis and subsequent biological evaluations a compelling research area. In this study, an NHC organocatalytic radical acylalkylation of 1,3-enynes using salicylaldehydes is presented, followed by a cascade intramolecular annulation, yielding a series of fluorinated isoflavone derivatives with substantial yields under environmental-friendly conditions. This approach, distinguished by its excellent modularity and high functional group tolerance, represents an unprecedented organocatalytic 1,3,4-trifunctionalization of 1,3-enynes designed for the green synthesis of bioactive isoflavones in a single step. Furthermore, it is demonstrated that these synthesized fluorinated isoflavonoids effectively suppress proliferation in breast cancer cells, with the most potent compound 8 also inhibiting migration in MDA-MB-231 cells.

Total synthesis of isoflavonoids

Covering: 2012 to 2024Isoflavonoids are phenolic compounds with wide structural diversity and a plethora of biological activities. Owing to their structural variation and potential health-promoting and other benefits, they have been targeted for synthesis. Herein, we review the synthesis of natural isoflavonoids belonging to different classes that include isoflavones, isoflavanones, isoflavans, isoflavenes, pterocarpans, rotenoids, coumaronochromones, and coumestans. The synthetic methodologies employed and advancements in synthetic strategies are highlighted.

Daidzein's potential in halting neurodegeneration: unveiling mechanistic insights

Neurological conditions encompassing a wide range of disorders pose significant challenges globally. The complex interactions among signaling pathways and molecular elements play pivotal roles in the initiation and progression of neurodegenerative diseases. Isoflavones have emerged as a promising candidate to fight against neurodegenerative diseases. Daidzein, a 7-hydroxy-3-(4-hydroxyphenyl)-chromen-4-one, belongs to the isoflavone class and exhibits a diverse pharmacological profile. It is found primarily in soybeans and soy products, as well as in some other legumes and herbs. Investigations into daidzein have revealed that it confers neuroprotection by inhibiting oxidative stress, inflammation, and apoptosis, which are key contributors to neuronal damage and degeneration. Activating pathways like PI3K/Akt/mTOR and promoting neurotrophic factors like BDNF by daidzein underscore its potential in supporting neuronal function and combating neurodegeneration. Daidzein's effects on dopamine provide further avenues for intervention in conditions like Parkinson's disease. Additionally, the modulation of inflammatory and NRF-2-antioxidant signaling by daidzein reinforces its neuroprotective role. Moreover, daidzein's interaction with receptors and cellular processes like ER-β, GPR30, MAO, VEGF, and GnRH highlights its multifaceted effects across multiple pathways involved in neuroprotection and neuronal function. This review article delves into the mechanistic interplay of various mediators in mediating the neuroprotective effects of daidzein. The review article consolidates and analyzes research published over nearly two decades (2005-2024) from various databases, including PubMed, Scopus, ScienceDirect, and Web of Science, to provide a comprehensive understanding of daidzein's effects and mechanisms in neuroprotection.

Prenylation of aromatic amino acids and plant phenolics by an aromatic prenyltransferase from Rasamsonia emersonii

Dimethylallyl tryptophan synthases (DMATSs) are aromatic prenyltransferases that catalyze the transfer of a prenyl moiety from a donor to an aromatic acceptor during the biosynthesis of microbial secondary metabolites. Due to their broad substrate scope, DMATSs are anticipated as biotechnological tools for producing bioactive prenylated aromatic compounds. Our study explored the substrate scope and product profile of a recombinant RePT, a novel DMATS from the thermophilic fungus Rasamsonia emersonii. Among a variety of aromatic substrates, RePT showed the highest substrate conversion for L-tryptophan and L-tyrosine (> 90%), yielding two mono-prenylated products in both cases. Nine phenolics from diverse phenolic subclasses were notably converted (> 10%), of which the stilbenes oxyresveratrol, piceatannol, pinostilbene, and resveratrol were the best acceptors (37-55% conversion). The position of prenylation was determined using NMR spectroscopy or annotated using MS2 fragmentation patterns, demonstrating that RePT mainly catalyzed mono-O-prenylation on the hydroxylated aromatic substrates. On L-tryptophan, a non-hydroxylated substrate, it preferentially catalyzed C7 prenylation with reverse N1 prenylation as a secondary reaction. Moreover, RePT also possessed substrate-dependent organic solvent tolerance in the presence of 20% (v/v) methanol or DMSO, where a significant conversion (> 90%) was maintained. Our study demonstrates the potential of RePT as a biocatalyst for the production of bioactive prenylated aromatic amino acids, stilbenes, and various phenolic compounds. KEY POINTS: • RePT catalyzes prenylation of diverse aromatic substrates. • RePT enables O-prenylation of phenolics, especially stilbenes. • The novel RePT remains active in 20% methanol or DMSO.

Isoflavonoid metabolism in leguminous plants: an update and perspectives

Isoflavonoids constitute a well-investigated category of phenylpropanoid-derived specialized metabolites primarily found in leguminous plants. They play a crucial role in legume development and interactions with the environment. Isoflavonoids usually function as phytoalexins, acting against pathogenic microbes in nature. Additionally, they serve as signaling molecules in rhizobial symbiosis. Notably, owing to their molecular structure resembling human estrogen, they are recognized as phytoestrogens, imparting positive effects on human health. This review comprehensively outlines recent advancements in research pertaining to isoflavonoid biosynthesis, transcriptional regulation, transport, and physiological functions, with a particular emphasis on soybean plants. Additionally, we pose several questions to encourage exploration into novel contributors to isoflavonoid metabolism and their potential roles in plant-microbe interactions.

Chemical Analysis and Biological Activities of Extracts Isolated from Symbiotic L. japonicus Plants

Plants produce a wide variety of secondary metabolites, including compounds with biological activities that could be used for the treatment of human diseases. In the present study, we examined the putative production of bioactive molecules in the legume plant Lotus japonicus, which engages into symbiotic relationships with beneficial soil microorganisms. To monitor the production of secondary metabolites when the plant develops beneficial symbiotic relationships, we performed single and double inoculations with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing Rhizobium bacteria. Plant extracts from non-inoculated and inoculated plants were chemically characterized and tested for anti-proliferative, apoptotic, and anti-inflammatory effects on human HEK-293 cells. Both shoot and root extracts from non-inoculated and inoculated plants significantly reduced the HEK-293 cell viability; however, a stronger effect was observed when the root extracts were tested. Shoot and root extracts from Rhizobium-inoculated plants and shoot extracts from AMF-inoculated plants showed apoptotic effects on human cells. Moreover, both shoot and root extracts from AMF-inoculated plants significantly reduced TNFα-induced NF-κB transcriptional activity, denoting anti-inflammatory activity. These results suggest that symbiotic L. japonicus plants are enriched with metabolites that have interesting biological activities and could be further explored for putative future use in the pharmaceutical sector.

RefMetaPlant: a reference metabolome database for plants across five major phyla

Plants are unique with tremendous chemical diversity and metabolic complexity, which is highlighted by estimates that green plants collectively produce metabolites numbering in the millions. Plant metabolites play crucial roles in all aspects of plant biology, like growth, development, stress responses, etc. However, the lack of a reference metabolome for plants, and paucity of high-quality standard compound spectral libraries and related analytical tools, have hindered the discovery and functional study of phytochemicals in plants. Here, by leveraging an advanced LC-MS platform, we generated untargeted mass spectral data from >150 plant species collected across the five major phyla. Using a self-developed computation protocol, we constructed reference metabolome for 153 plant species. A 'Reference Metabolome Database for Plants' (RefMetaPlant) was built to encompass the reference metabolome, integrated standard compound mass spectral libraries for annotation, and related query and analytical tools like 'LC-MS/MS Query', 'RefMetaBlast' and 'CompoundLibBlast' for searches and profiling of plant metabolome and metabolite identification. Analogous to a reference genome in genomic research, RefMetaPlant provides a powerful platform to support plant genome-scale metabolite analysis to promote knowledge/data sharing and collaboration in the field of metabolomics. RefMetaPlant is freely available at https://www.biosino.org/RefMetaDB/.

Neuroprotective potential of formononetin, a naturally occurring isoflavone phytoestrogen

The increased prevalence of neurological illnesses is a burgeoning challenge to the public healthcare system and presents greater financial pressure. Formononetin, an O-methylated isoflavone, has gained a lot of attention due to its neuroprotective potential explored in several investigations. Formononetin is widely found in legumes and several types of clovers including Trifolium pratense L., Astragalus membranaceus, Sophora tomentosa, etc. Formononetin modulates various endogenous mediators to confer neuroprotection. It prevents RAGE activation that results in the inhibition of neuronal damage via downregulating the level of ROS and proinflammatory cytokines. Furthermore, formononetin also increases the expression of ADAM-10, which affects the pathology of neurodegenerative disease by lowering tau phosphorylation, maintaining synaptic plasticity, and boosting hippocampus neurogenesis. Besides these, formononetin also increases the expression of antioxidants, Nrf-2, PI3K, ApoJ, and LRP1. Whereas, reduces the expression of p65-NF-κB and proinflammatory cytokines. It also inhibits the deposition of Aβ and MAO-B activity. An inhibition of Aβ/RAGE-induced activation of MAPK and NOX governs the protection elicited by formononetin against inflammatory and oxidative stress-induced neuronal damage. Besides this, PI3K/Akt and ER-α-mediated activation of ADAM10, ApoJ/LRP1-mediated clearance of Aβ, and MAO-B inhibition-mediated preservation of dopaminergic neurons integrity are the major modulations produced by formononetin. This review covers the biosynthesis of formononetin and key molecular pathways modulated by formononetin to confer neuroprotection.

Insights into the missing apiosylation step in flavonoid apiosides biosynthesis of Leguminosae plants

Apiose is a natural pentose containing an unusual branched-chain structure. Apiosides are bioactive natural products widely present in the plant kingdom. However, little is known on the key apiosylation reaction in the biosynthetic pathways of apiosides. In this work, we discover an apiosyltransferase GuApiGT from Glycyrrhiza uralensis. GuApiGT could efficiently catalyze 2″-O-apiosylation of flavonoid glycosides, and exhibits strict selectivity towards UDP-apiose. We further solve the crystal structure of GuApiGT, determine a key sugar-binding motif (RLGSDH) through structural analysis and theoretical calculations, and obtain mutants with altered sugar selectivity through protein engineering. Moreover, we discover 121 candidate apiosyltransferase genes from Leguminosae plants, and identify the functions of 4 enzymes. Finally, we introduce GuApiGT and its upstream genes into Nicotiana benthamiana, and complete de novo biosynthesis of a series of flavonoid apiosides. This work reports an efficient phenolic apiosyltransferase, and reveals mechanisms for its sugar donor selectivity.

Primary and Secondary Metabolites in Lotus japonicus

Lotus japonicus is a leguminous model plant used to gain insight into plant physiology, stress response, and especially symbiotic plant-microbe interactions, such as root nodule symbiosis or arbuscular mycorrhiza. Responses to changing environmental conditions, stress, microbes, or insect pests are generally accompanied by changes in primary and secondary metabolism to account for physiological needs or to produce defensive or signaling compounds. Here we provide an overview of the primary and secondary metabolites identified in L. japonicus to date. Identification of the metabolites is mainly based on mass spectral tags (MSTs) obtained by gas chromatography linked with tandem mass spectrometry (GC-MS/MS) or liquid chromatography-MS/MS (LC-MS/MS). These MSTs contain retention index and mass spectral information, which are compared to databases with MSTs of authentic standards. More than 600 metabolites are grouped into compound classes such as polyphenols, carbohydrates, organic acids and phosphates, lipids, amino acids, nitrogenous compounds, phytohormones, and additional defense compounds. Their physiological effects are briefly discussed, and the detection methods are explained. This review of the exisiting literature on L. japonicus metabolites provides a valuable basis for future metabolomics studies.

Advances in the study of the function and mechanism of the action of flavonoids in plants under environmental stresses

MAIN CONCLUSION

This review summarizes the anti-stress effects of flavonoids in plants and highlights its role in the regulation of polar auxin transport and free radical scavenging mechanism. As secondary metabolites widely present in plants, flavonoids play a vital function in plant growth, but also in resistance to stresses. This review introduces the classification, structure and synthetic pathways of flavonoids. The effects of flavonoids in plant stress resistance were enumerated, and the mechanism of flavonoids in plant stress resistance was discussed in detail. It is clarified that plants under stress accumulate flavonoids by regulating the expression of flavonoid synthase genes. It was also determined that the synthesized flavonoids are transported in plants through three pathways: membrane transport proteins, vesicles, and bound to glutathione S-transferase (GST). At the same time, the paper explores that flavonoids regulate polar auxin transport (PAT) by acting on the auxin export carrier PIN-FORMED (PIN) in the form of ATP-binding cassette subfamily B/P-glycoprotein (ABCB/PGP) transporter, which can help plants to respond in a more dominant form to stress. We have demonstrated that the number and location of hydroxyl groups in the structure of flavonoids can determine their free radical scavenging ability and also elucidated the mechanism by which flavonoids exert free radical removal in cells. We also identified flavonoids as signaling molecules to promote rhizobial nodulation and colonization of arbuscular mycorrhizal fungi (AMF) to enhance plant-microbial symbiosis in defense to stresses. Given all this knowledge, we can foresee that the in-depth study of flavonoids will be an essential way to reveal plant tolerance and enhance plant stress resistance.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

The Suzuki-Miyaura Cross-Coupling-Claisen Rearrangement-Cross-Metathesis Approach to Prenylated Isoflavones

Isoflavones were synthesized via Suzuki-Miyaura coupling of 3-iodochromones and para-methoxybenzene- and para-phenolboronic acid. In our hands, conditions commonly used for similar cross couplings turned out to be unsuccessful or difficult to reproduce, for example, due to the unplanned partial cleavage of MOM-protecting groups. Using Pd(dba)₂ as a precatalyst and tricyclohexylphosphine as an activating ligand, reliable cross-coupling conditions were identified. In all cases, notably higher yields of isoflavones were obtained with para-phenolboronic acid than with para-methoxybenzene boronic acid. This observation and the commercial availability of para-phenolboronic acid suggest that for the synthesis of the important 3'-prenyl- or 3',5'-diprenylisoflavone substitution pattern a synthetic route that introduces the prenyl substituents after the Pd-catalyzed cross-coupling step, thereby avoiding laborious and protecting-group-intensive multistep syntheses of C-prenylated arene boronic acids, is advantageous.

The Role of Isoflavones in the Prevention of Breast Cancer and Prostate Cancer

This narrative review summarizes epidemiological studies on breast cancer and prostate cancer with an overview of their global incidence distribution to investigate the relationship between these diseases and diet. The biological properties, mechanisms of action, and available data supporting the potential role of isoflavones in the prevention of breast cancer and prostate cancer are discussed. Studies evaluating the effects of isoflavones in tissue cultures of normal and malignant breast and prostate cells, as well as the current body of research regarding the effects of isoflavones attained through multiple modifications of cellular molecular signaling pathways and control of oxidative stress, are summarized. Furthermore, this review compiles literature sources reporting on the following: (1) levels of estrogen in breast and prostate tissue; (2) levels of isoflavones in the normal and malignant tissue of these organs in European and Asian populations; (3) average concentrations of isoflavones in the secretion of these organs (milk and semen). Finally, particular emphasis is placed on studies investigating the effect of isoflavones on tissues via estrogen receptors (ER).

Phytochemical Analysis and Antiproliferative Activity of Ulex gallii Planch. (Fabaceae), a Medicinal Plant from Galicia (Spain)

The genus Ulex comprises thirteen accepted species of perennial shrubs in the family Fabaceae. In Galicia (Spain) many of these are considered spontaneous colonizing species, which are easy to establish and maintain. Among them, Ulex gallii Planch. is used in traditional medicine for the same anti-infective, hypotensive and diuretic purposes as Ulex europaeus L., which is the most studied species. Likewise, some studies have described the antitumoral properties of several species. However, there are few scientific studies that justify the use of Ulex gallii Planch. and nothing has been reported about its composition to date. In our study, the entire plant was extracted with methanol and the crude extract was subjected to liquid phase extraction with distinct solvents, yielding three fractions: hexane (H), dichloromethane (D) and methanol (M), which were subsequently fractionated. The dichloromethane (D5, D7 and D8) and methanol (M4) sub-fractions showed antiproliferative activity on A549 (lung cancer) and AGS (stomach cancer) cell lines, and caspase 3/7 activity assessment and DNA quantification were also performed. Targeted analysis via UHPLC-QToF, in combination with untargeted analysis via MS-Dial, MS-Finder and Global Natural Products Social Molecular Networking (GNPS), allowed us to tentatively identify different metabolites in these sub-fractions, mostly flavonoids, that might be involved in their antiproliferative activity.

Metabolic profiling and transcriptome analysis provide insights into the accumulation of flavonoids in chayote fruit during storage

Chayote (Sechium edulel) fruits are rich in flavonoids, folate, and low-calorie food. However, studies about the flavonoids and the corresponding regulatory mechanism of flavonoid synthesis in chayote fruits was still unclear. In present study, an integrated transcriptome and metabolite analysis of chayote fruits at three different storage stages were conducted to explore the flavonoid compositions and gene expression associated with flavonoid synthesis. Through the UPLC-MS/MS analysis, a total of 57 flavonoid compounds were detected. Of these, 42 flavonoid glycosides were significantly differential accumulation in chayote fruits at three different storage stages. Many genes associated with flavonoid synthesis were differentially expressed in chayote fruits at three different storage stages through RNA-seq analysis, including structural genes and some TFs. There was a high correlation between RNA-seq analysis and metabolite profiling, and the expression level of candidate genes in the flavonoid synthesis pathway were consistent with the dynamic changes of flavonoids. In addition, one R2R3-MYB transcription factor, FSG0057100, was defined as the critical regulatory gene of flavonoid synthesis. Furthermore, exogenous application of phenylalanine increased the total content of flavonoids and promoted some flavonoid biosynthesis-related gene expression in chayote fruits. The above results not only make us better understand the molecular mechanism of flavonoid synthesis in chayote fruits, but also contribute to the promotion and application of chayote products.

Guaiacol oxidation: theoretical insight into thermochemistry of radical processes involving methoxy group demethylation

Guaiacol (2-methoxyphenol) is naturally occurring phenolic compound essential in various research areas. Oxidative transformation of guaiacol can lead to the formation of various products, including 1,3-benzodioxole or ortho-quinone. Therefore, this study is focused on the investigation of the reaction enthalpies of experimentally observed guaiacol oxidation pathways in gas-phase, as well as in non-polar environment and aqueous solution. Corresponding Density Functional Theory (DFT) calculations were carried out using two hybrid functionals (M06-2X and B3LYP-D3). All reaction enthalpies, as well as Gibbs free energies, were also calculated using composite ab initio G4 method. M06-2X and G4 results show mutual agreement and the best accordance with available experimentally determined reaction enthalpies. Obtained Gibbs free reaction energies indicate that formation of ortho-quinone is thermodynamically preferred to formation of 1,3-benzodioxole at 298 K in studied environments. Moreover, all computational methods confirm that the reaction enthalpy of methoxy group demethylation, i.e. O-C bond dissociation enthalpy (BDE), is substantially lower in comparison to the enthalpy of hydrogen atom transfer from phenolic OH group. In the case of phenoxide anion of guaiacol, which can be formed in ionization supporting solvents, O-C BDE shows further significant decrease, exceeding 50 kJ mol^-1, in comparison to parent molecule.HIGHLIGHTSReaction enthalpies and Gibbs free energies of individual steps of guaiacol transformation to 1,3-benzodioxole or ortho-quinone are studied in three environments.M06-2X functional and composite ab initio G4 methods provide reliable O-H and O-C bond dissociation enthalpies.Dissociation enthalpy of methoxy group O-C bond is lower by ca. 100 kJ mol^-1 in comparison to phenolic O-H bond.Phenoxide anion of guaiacol shows substantially lower O-C BDE than parent molecule.

Synthesis of 7,2'-Dihydroxy-4',5'-Dimethoxyisoflavanone, a Phytoestrogen with Derma Papilla Cell Proliferative Activity

This paper reports a concise and scalable method for the synthesis of the phytoestrogen 7,2′-dihydroxy-4′,5′-dimethoxyisoflavanone 1 via an optimized synthetic route. Compound 1 was readily obtained in 11 steps and 11% overall yield on a gram scale from commercially available 3,4-dimethoxyphenol. The key features of the synthesis include the construction of the deoxybenzoin unit through a sequence of Claisen rearrangement, oxidative cleavage, and aryllithium addition and the efficient synthesis of the isoflavanone architecture from highly functionalized 2-hydroxyketone.

Therapeutic Potential and Mechanisms of Novel Simple O-Substituted Isoflavones against Cerebral Ischemia Reperfusion

Isoflavones have been widely studied and have attracted extensive attention in fields ranging from chemotaxonomy and plant physiology to human nutrition and medicine. Isoflavones are often divided into three subgroups: simple O-substituted derivatives, prenylated derivatives, and glycosides. Simple O-substituted isoflavones and their glycosides, such as daidzein (daidzin), genistein (genistin), glycitein (glycitin), biochanin A (astroside), and formononetin (ononin), are the most common ingredients in legumes and are considered as phytoestrogens for daily dietary hormone replacement therapy due to their structural similarity to 17-β-estradiol. On the basis of the known estrogen-like potency, these above isoflavones possess multiple pharmacological activities such as antioxidant, anti-inflammatory, anticancer, anti-angiogenetic, hepatoprotective, antidiabetic, antilipidemic, anti-osteoporotic, and neuroprotective activities. However, there are very few review studies on the protective effects of these novel isoflavones and their related compounds in cerebral ischemia reperfusion. This review primarily focuses on the biosynthesis, metabolism, and neuroprotective mechanism of these aforementioned novel isoflavones in cerebral ischemia reperfusion. From these published works in in vitro and in vivo studies, simple O-substituted isoflavones could serve as promising therapeutic compounds for the prevention and treatment of cerebral ischemia reperfusion via their estrogenic receptor properties and neuron-modulatory, antioxidant, anti-inflammatory, and anti-apoptotic effects. The detailed mechanism of the protective effects of simple O-substituted isoflavones against cerebral ischemia reperfusion might be related to the PI3K/AKT/ERK/mTOR or GSK-3β pathway, eNOS/Keap1/Nrf-2/HO-1 pathway, TLRs/TIRAP/MyD88/NFκ-B pathway, and Bcl-2-regulated anti-apoptotic pathway. However, clinical trials are needed to verify their potential on cerebral ischemia reperfusion because past studies were conducted with rodents and prophylactic administration.

Bioactive pterocarpans from the root of Astragalus membranaceus var. mongholicus

Eleven undescribed and three known pterocarpans were isolated and identified from the traditional Chinese medicine "Huang-qi", Astragali Radix (the root of Astragalus membranaceus var. mongholicus (Bunge) P.K.Hsiao). The structures of these pterocarpans were determined using spectroscopic, X-ray crystallographic, quantum chemical calculation, and chemical methods. Pterocarpans, almost exclusively distributed in the family of Leguminosae, are the second largest subgroup of isoflavanoids. However, pterocarpan glycoside number is limited, most of which are glucosides, and only one pterocarpan apioside was isolated from nature. Notably, nine rare apiosyl-containing pterocarpan glycosides were isolated and identified. The hypoglycemic activities of all these compounds were evaluated using α-glucosidase and DPP-IV inhibitory assays respectively, and some isolates displayed the α-glucosidase inhibitory function. The antioxidant activities of all compounds were evaluated using the ORAC and DPPH radical scavenging assays, respectively. All compounds exhibited varying degrees of oxygen radical absorbance capacity, and some compounds displayed DPPH radical scavenging ability.

Extraction and Identification of Effective Compounds from Natural Plants

Most botanical species contain various types of bioactive compounds. This study focusses on the extraction and identification of bioactive compounds from Calicotome spinosa (Gorse), including flavones, α-linolenic acid and sugar. During the investigation of gorse flowers, leaves and bark, flavones were isolated from the bark and leaves. Calicotome spinosa showed a total isoflavonoid content of 1.5% from the bark of gorse and 1.3% from the leaves. To find the best conditions for flavone extraction, samples of Calicotome spinosa were extracted with different solvents (methanol, water and acetonitrile). Methanol was found to be a suitable solvent to selectively extract flavone. An unsaturated cis fatty acid (α-linolenic acid, C18:3 ∆9, 12, 15) was identified as the principal component of the triacylglycerol fraction from the flowers. Hydrolyses process conditions were used to study Gorse wood. The results indicated that the wood of gorse is not a suitable substance for making paper. The extracted bioactive compounds were analysed using NMR, GCMS, UV, TLC and Fibre Analyser techniques. The extracted compounds offered uses as antioxidants and agricultural chemicals in addition to other benefits.

Thermochemistry of antioxidant action of isoflavones and their deprotonated forms in aqueous solution: hydrogen or electron transfer?

Isoflavones possessing several weak acidic hydroxyl groups can undergo successive deprotonations in aqueous solutions. Therefore, their antioxidant properties cannot be ascribed only to the neutral forms but also to corresponding phenoxide anions. It was already confirmed that isoflavones prefer the formation of dianions in aqueous solution. For eight isoflavones and their preferred (poly)deprotonated forms, thermochemistry of hydrogen atom transfer and electron abstraction was studied in terms of corresponding reaction enthalpies, i.e., O—H bond dissociation enthalpies and ionization potentials. Our results clearly indicate that the increase in negative charge causes significant drop in ionization potential and bond dissociation enthalpy. On the other hand, proton affinities show the opposite trend. Thus, it is unfeasible to find a generally valid trend for dianions — corresponding reaction enthalpies strongly depend on the structure of isoflavone, especially on the number/positions of OH groups.

Fabaceae: a significant flavonoid source for plant and human health

The Fabaceae is recognized as the third largest and one of the most influential families among the flowering plants. Furthermore, its name is linked to “Legumes”, which represent a vast group of angiosperms in the continents utilized as crops, forages, and green manures. It is recognized for diverse constituents, covering both primary metabolites include lectins, chitinases, various proteases, and α-amylase inhibitors, as well as secondary metabolites include flavonoids, alkaloids, terpenoids, tannins, and phenolics. Fabaceae flavonoid plays an important role in the legumes’ adaptability to biological surroundings as defensive agents (phytoalexins) and as chemical signals in a symbiotic relationship with a bacterial species known as rhizobia. Considering their important role in plant defense and benefits to human healthiness, a number of studies on the Fabaceae plant have been performed, namely isolation and screening of the purified compounds and their biological activity. This study outlines specified issues on the chemical structure, biosynthesis, biological activities, and medicinal uses of Fabaceae compounds.

In-depth phytochemical and biological studies on potential AChE inhibitors in red and zigzag clover dry extracts using reversed-phase liquid chromatography (RP-LC) coupled with photodiode array (PDA) and electron spray ionization-quadrupole/time of flight-mass spectrometric (ESI-QToF/MS-MS) detection and thin-layer chromatography-bioautography

In the study, Trifolium medium L. and T. pratense L. were used to obtain lyophilisates which were named as TML and TPL, respectively. The former clover taxon represents a little explored species, while the latter one is often found in dietary supplements and functional foods due to the content of isoflavones that alleviate various menopausal symptoms. Detailed phytochemical profiles of both lyophilisates were examined and compared using coupled chromatographic (RP-LC) and spectroscopic PDA/ESI-QToF/MS-MS methods. A total of 54 and 55 compounds were identified in TML and TPL, respectively. Close chemotaxonomic similarities were confirmed for both clover taxa examined, especially in terms of the most abundant isoflavones and hydroxycinnamates. For the first time, neurotropic polyphenols (AChE inhibitors) were identified in clover extracts using TLC-bioautography. In this group, caffeoylmalic acid exhibited significant AChE inhibitory effect confirming the potential of TPL and TML to support physiological functions of the endocrine and nervous systems.

Amphimas pterocarpoides harms.: An Evaluation of flavonoid and phenolic contents, wound healing, anthelmintic and antioxidant activities of the leaves and stem bark

The present study evaluated the wound healing, anthelmintic and antioxidant potentials of crude methanol extracts and fractions (petroleum ether, ethyl acetate and methanol) of the leaves and stem bark of Amphimas pterocarpoides. Wound healing activity was determined by the dermal excision model in rats; anthelmintic activity was evaluated by the adult worm motility test using the adult Indian worm, Pheretima postuma. Total flavonoid, phenolic content and antioxidant activity were assessed by the aluminum chloride colorimetric, Folin Ciocalteu, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and total antioxidant capacity (TAC) assays respectively. HPLC/UV fingerprints were developed for quality control. The maximum amount of phenolics and flavonoids were detected in the methanol fractions of the stem bark (225.0 ± 20.0 mg/g gallic acid equivalent (GAE) and 201.0 ± 1.41 mg/g quercetin equivalent (QCE) respectively) and leaves (84.54 ± 1.36 mg/g GAE and 130.7 ± 1.71 mg/g QCE, respectively). Both leaf and bark displayed remarkable free radical scavenging and TAC with the highest effect given by the methanol fractions. Significant (p < 0.05) wound contraction was achieved by topical application of the leaf (APL) and stem bark (APS) ointments (5-15%) with >90 % wound surface closure for 1% silver sulphadiazine, APS 15% and APL 10% treated groups by day 15. APL and APS demonstrated a concentration- and time-dependent paralysis and mortality of the P. posthuma with APL (6.25 mg/mL) causing worm paralysis at 82.60 min and death at 93 min, better than 10 mg/mL albendazole (paralysis at 76.30 min; death at 117 min). Tannins, triterpenoids, phytosterols, flavonoids, saponins and coumarins were detected in the leaves and bark. The results have proven the potential of A. pterocarpoides as a wound healing and anthelmintic agent, giving scientific credence to its use in traditional medicine.

From Microns to Meters: Exploring Advances in Legume Microbiome Diversity for Agroecosystem Benefits

Legumes are of primary importance for agroecosystems because they provide protein-rich foods and enhance soil fertility through fixed atmospheric nitrogen. The legume-rhizobia symbiosis that makes this possible has been extensively studied, from basic research on biochemical signaling to practical applications in cropping systems. While rhizobia are the most-studied group of associated microorganisms, the functional benefit they confer to their legume hosts by fixing nitrogen is not performed in isolation. Indeed, non-rhizobia members of the rhizosphere and nodule microbiome are now understood to contribute in multiple ways to nodule formation, legume fitness, and other agroecosystem services. In this review, we summarize advances contributing to our understanding of the diversity and composition of bacterial members of the belowground legume microbiome. We also highlight applied work in legume food and forage crops that link microbial community composition with plant functional benefits. Ultimately, further research will assist in the development of multi-species microbial inoculants and cropping systems that maximize plant nutrient benefits, while reducing sources of agricultural pollution.

How diverse is the chemistry and plant origin of Brazilian propolis?

Propolis is a honey bee product containing chiefly beeswax and resins originated from plant buds or exudates. Propolis resin exerts a diversity of biological activities, such as antitumoral, anti-inflammatory, antimicrobial, and defense of the hive against pathogens. Chemical standardization and identification of botanical sources is crucial for characterization of propolis. Types of Brazilian propolis are characteristic of geographical regions and respective biomes, such as savannas (Cerrado), mangroves, dry forest (Caatinga), rain forests (Amazon, Atlantic, and Interior forests), altitudinal fields ("Campos Rupestres"), Pantanal, and Araucaria forests. Despite the wide diversity of Brazilian biomes and flora, relatively few types of Brazilian propolis and corresponding resin plant sources have been reported. Factors accounting for the restricted number of known types of Brazilian propolis and plant sources are tentatively pointed out. Among them, the paper discusses constraints that honey bees must overcome to collect plant exudates, including the characteristics of the lapping-chewing mouthpart of honey bee, which limit their possibilities to cut and chew plant tissues, as well as chemical requirements that plant resins must fulfil, involving antimicrobial activity of its constituents and innocuity to the insects. Although much still needs to be done toward a more comprehensive picture of Brazilian propolis types and corresponding plant origins, the prospects indicate that the actual diversity of plant sources of honey bee propolis will remain relatively low.

Scope and Applications of 2,3-Oxidative Aryl Rearrangements for the Synthesis of Isoflavone Natural Products

The reaction of flavanones with hypervalent iodine reagents was investigated with a view to the synthesis of naturally occurring isoflavones. In contrast to several previous reports in the literature, we did not observe the formation of any benzofurans via a ring contraction pathway, but could isolate only isoflavones, resulting from an oxidative 2,3-aryl rearrangement, and flavones, resulting from an oxidation of the flavanones. Although the 2,3-oxidative rearrangement allows a synthetically useful approach toward some isoflavone natural products due to the convenient accessibility of the required starting materials, the overall synthetic utility and generality of the reaction appear to be more limited than previous literature reports suggest.

Recent Advances in Heterologous Synthesis Paving Way for Future Green-Modular Bioindustries: A Review With Special Reference to Isoflavonoids

Isoflavonoids are well-known plant secondary metabolites that have gained importance in recent time due to their multiple nutraceutical and pharmaceutical applications. In plants, isoflavonoids play a role in plant defense and can confer the host plant a competitive advantage to survive and flourish under environmental challenges. In animals, isoflavonoids have been found to interact with multiple signaling pathways and have demonstrated estrogenic, antioxidant and anti-oncologic activities in vivo. The activity of isoflavonoids in the estrogen pathways is such that the class has also been collectively called phytoestrogens. Over 2,400 isoflavonoids, predominantly from legumes, have been identified so far. The biosynthetic pathways of several key isoflavonoids have been established, and the genes and regulatory components involved in the biosynthesis have been characterized. The biosynthesis and accumulation of isoflavonoids in plants are regulated by multiple complex environmental and genetic factors and interactions. Due to this complexity of secondary metabolism regulation, the export and engineering of isoflavonoid biosynthetic pathways into non-endogenous plants are difficult, and instead, the microorganisms Saccharomyces cerevisiae and Escherichia coli have been adapted and engineered for heterologous isoflavonoid synthesis. However, the current ex-planta production approaches have been limited due to slow enzyme kinetics and traditionally laborious genetic engineering methods and require further optimization and development to address the required titers, reaction rates and yield for commercial application. With recent progress in metabolic engineering and the availability of advanced synthetic biology tools, it is envisaged that highly efficient heterologous hosts will soon be engineered to fulfill the growing market demand.

In Vitro Antiplasmodial and Cytotoxic Activities of Compounds from the Roots of Eriosema montanum Baker f. (Fabaceae)

Malaria remains one of the leading causes of death in sub-Saharan Africa, ranked in the top three infectious diseases in the world. Plants of the Eriosema genus have been reported to be used for the treatment of this disease, but scientific evidence is still missing for some of them. In the present study, the in vitro antiplasmodial activity of the crude extract and compounds from Eriosema montanum Baker f. roots were tested against the 3D7 strain of Plasmodium falciparum and revealed using the SYBR Green, a DNA intercalating compound. The cytotoxicity effect of the compounds on a human cancer cell line (THP-1) was assessed to determine their selectivity index. It was found that the crude extract of the plant displayed a significant antiplasmodial activity with an IC₅₀ (µg/mL) = 17.68 ± 4.030 and a cytotoxic activity with a CC₅₀ (µg/mL) = 101.5 ± 12.6, corresponding to a selective antiplasmodial activity of 5.7. Bioactivity-guided isolation of the major compounds of the roots' crude extract afforded seven compounds, including genistein, genistin and eucomic acid. Under our experimental conditions, using Artemisinin as a positive control, eucomic acid showed the best inhibitory activity against the P. falciparum 3D7, a well-known chloroquine-sensitive strain. The present results provide a referential basis to support the traditional use of Eriosema species in the treatment of malaria.

Temperature- and Reagent-Controlled Complementary Syn- and Anti-Selective Enolboration-Aldolization of Substituted Phenylacetates

In contrast to methyl phenylacetates, methyl arylacetates do not provide syn-aldols in the dicyclohexylboron triflate/triethylamine (Chx₂BOTf/Et₃N)-mediated enolboration-aldolization reaction. However, a combination of a less bulky boron reagent (dibutylboron triflate, n-Bu₂BOTf), a bulky amine (i-Pr₂NEt), and ambient temperature is required to obtain syn-aldols from methyl arylacetates. The corresponding anti-aldol products have been synthesized by the enolboration-aldolization of methyl arylacetates in the presence of Chx₂BOTf/Et₃N at a lower temperature. We report the first example of a complementary syn- and anti-selective enolboration-aldolization of arylacetates.

Three new monocyclic monoterpenoid O-glycosides from the roots of Glycyrrhiza uralensis

Three new monocyclic monoterpenoid containing β-D-apiofuranosyl-(1→2)-O-β-D-glucopyranosyl moieties, together with three other known monocyclic monoterpenoid O-glycosides, were obtained from the roots of Glycyrrhiza uralensis for the first time. Their structures were determined by UV, IR, HRESIMS, and 1D and 2D NMR data.[Formula: see text].

Chemosystematic and evolutionary trends of the genistoid clade sensu stricto (Papilionoideae, Fabaceae)

The Papilionoideae, which comprises 503 genera and approximately 14,000 species, is the largest and most diverse subfamily of the Fabaceae family. In this subfamily, the Crotalarieae, Genisteae, Podalyrieae, Thermopsideae, Sophoreae and Euchresteae tribes are closely related by micro and macromolecular features, thus forming the genistoid clade. This group combines well-known genera, whereas other genera lack phytochemical and chemotaxonomic studies. Thus, this work aimed to characterize the special metabolites in these genera in order to define the chemical profile, the micromolecular markers and the chemical diversity, as well as to evaluate the group evolutionary trends. Flavonoids and alkaloids were identified as chemosystematic markers for the studied tribes due to high occurrence number and structural diversity. Among flavonoids, the flavones and isoflavones predominated. Low protection indexes of flavonoid hydroxyls by O-glycosylation or O-methylation were observed, whereas C-prenylation and C-glycosylation were frequent, mainly at C-6 and C-8 positions. The flavone/flavonol ratio shows the predominance of the flavones. Quinolizidine and piperidine alkaloids were present in most genera. Pyrrolizidine alkaloids were found in a few genera from Thermopsideae, Genisteae and Crotalarieae, which suggests a mechanism of adaptive convergence. Cluster analysis allowed separation of genera for each tribe by chemical similarities. The micromolecular trends of protection of flavonoid hydroxyls and alkaloid oxidation indicate the genistoid clade is through evolutionary transition, which is consistent with its phylogenetic position in the Papilionoideae subfamily.

Total Syntheses of Prenylated Isoflavones from Erythrina sacleuxii and Their Antibacterial Activity: 5-Deoxy-3'-prenylbiochanin A and Erysubin F

The prenylated isoflavones 5-deoxyprenylbiochanin A (7-hydroxy-4'-methoxy-3'-prenylisoflavone) and erysubin F (7,4'-dihydroxy-8,3'-diprenylisoflavone) were synthesized for the first time, starting from mono- or di-O-allylated chalcones, and the structure of 5-deoxy-3'-prenylbiochanin A was corroborated by single-crystal X-ray diffraction analysis. Flavanones are key intermediates in the synthesis. Their reaction with hypervalent iodine reagents affords isoflavones via a 2,3-oxidative rearrangement and the corresponding flavone isomers via 2,3-dehydrogenation. This enabled a synthesis of 7,4'-dihydroxy-8,3'-diprenylflavone, a non-natural regioisomer of erysubin F. Erysubin F (8), 7,4'-dihydroxy-8,3'-diprenylflavone (27), and 5-deoxy-3'-prenylbiochanin A (7) were tested against three bacterial strains and one fungal pathogen. All three compounds are inactive against Salmonella enterica subsp. enterica (NCTC 13349), Escherichia coli (ATCC 25922), and Candida albicans (ATCC 90028), with MIC values greater than 80.0 μM. The diprenylated natural product erysubin F (8) and its flavone isomer 7,4'-dihydroxy-8,3'-diprenylflavone (27) show in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300) at MIC values of 15.4 and 20.5 μM, respectively. In contrast, the monoprenylated 5-deoxy-3'-prenylbiochanin A (7) is inactive against this MRSA strain.

Flavonoids and Isoflavonoids Biosynthesis in the Model Legume Lotus japonicus; Connections to Nitrogen Metabolism and Photorespiration

Phenylpropanoid metabolism represents an important metabolic pathway from which originates a wide number of secondary metabolites derived from phenylalanine or tyrosine, such as flavonoids and isoflavonoids, crucial molecules in plants implicated in a large number of biological processes. Therefore, various types of interconnection exist between different aspects of nitrogen metabolism and the biosynthesis of these compounds. For legumes, flavonoids and isoflavonoids are postulated to play pivotal roles in adaptation to their biological environments, both as defensive compounds (phytoalexins) and as chemical signals in symbiotic nitrogen fixation with rhizobia. In this paper, we summarize the recent progress made in the characterization of flavonoid and isoflavonoid biosynthetic pathways in the model legume Lotus japonicus (Regel) Larsen under different abiotic stress situations, such as drought, the impairment of photorespiration and UV-B irradiation. Emphasis is placed on results obtained using photorespiratory mutants deficient in glutamine synthetase. The results provide different types of evidence showing that an enhancement of isoflavonoid compared to standard flavonol metabolism frequently occurs in Lotus under abiotic stress conditions. The advance produced in the analysis of isoflavonoid regulatory proteins by the use of co-expression networks, particularly MYB transcription factors, is also described. The results obtained in Lotus japonicus plants can be also extrapolated to other cultivated legume species, such as soybean, of extraordinary agronomic importance with a high impact in feeding, oil production and human health.

Preliminary screening of the aqueous extracts of twenty-three different seaweed species in Sri Lanka with in-vitro and in-vivo assays

Background

Seaweeds are an important source of bioactive compounds which are applied in various aspects of medicinal investigations. The present study was conducted to investigate cytoxicity (in-vitro and in-vivo) and wound healing activity of different seaweed species in Sri Lanka.

Methods

Twenty-three seaweed samples, belonging to Phaeophyta (Brown), Chlorophyta (Green) and Rhodophyta (Red) were used for the experiments. Samples were collected from the inter-tidal and the sub-tidal habitats around Sri Lankan coast (Southern, Northern and North-western). Aqueous seaweed extracts were tested for cytotoxic and wound healing activity; in-vitro and in-vivo. To determine toxicity of aqueous seaweed extracts, brine shrimp lethality assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay on mouse fibroblasts (L929) cell line were performed. Cell migration induction of seaweed extracts was assessed by scratch wound healing assay using L929 cell line. Based on the our previous experiments S.ilicifolium (SW23) was selected for the in vivo study to confirm our hypothesis. Albino mice (BALB/c) were divided into three groups (12 in each) and a circular area (44.07 ± 02.51 mm²) of full skin was excised to create a wound in mice group II and III. Group III received aqueous extract of Sargasum illicifolium (400 mg/kg BW/day for 12 days, orally), Group II received distilled water for 12 days whereas Group I was used as the control group and it was tested without forming wounds and without providing any treatment. Further, the expression level of Tumor Necrosis Factor (TNF-α) and Transforming Growth Factor-β (TGF-β) via RT-PCR were measured every three days until the end of the experiment.

Results

Phytochemical tests showed positive results to flavonoids in all the selected green seaweeds and alkaloids were observed in red seaweeds. In the toxicity assay, red seaweed, Acanthophora spicifera (SW17) was found to be highly effective on nauplii of brine shrimp (LC₅₀ = 0.072 μg/μl). LC₅₀ value of green seaweed species, Caulerpa racemosa (SW02 and SW08) and Caulerpa sertularioides (SW10) was not found within the tested concentration series. The highest cytotoxic effect on L929 cell line was exhibited by aqueous extracts of red seaweed; Jania adhaereus with 50.70 ± 7.304% cell viability compared with control group. The highest cell migration activity was observed in L929 cell line group treated with extracts of green seaweed namely; Halimeda opuntin (SW07) and extracts of brown seaweed namely; Stoechospermum polypodioides (SW11). Extracts of S. illicifolium (SW23) exhibited a significantly enhanced wound healing activity in mice group III within three days (P < 0.05) with an open wound area of 17.35 ± 1.94 mm² compared with control group (26.29 ± 2.42 mm²). TGF-β gene expression peaked on 6^th day of post-wound and subsequently decreased on 9^th day of post-wound in mice group III. TNF-α expression was suppressed in mice group III whereas it was elevated in group II. TGF-β expression is enhanced in the treatment group compared to the control group.

Conclusions

Aqueous extracts of selected seaweeds are a significant source of potential compounds with wound healing properties, which might be helpful in the healing of various wounds. This also infers that many species of brown and red seaweeds have the potential of wound healing, specifically, Sargasum illicifolium and Jania adhaereus could be a potential candidate for in-vivo studies related to wound healing and cancer therapy in the near future.

Effects of Isolated Isoflavones Intake on Health

BACKGROUND

Isoflavones are naturally occurring flavonoids, commonly found in the food consumed for centuries in the East-Asian population, characterized by a structure able to exert nonsteroidal estrogen-like activity on human cells. They have attracted researcher interest all around the word, following the results obtained in epidemiological and clinical studies. The involvement of isoflavones and their metabolites in various biological processes suggests that they can influence several metabolic pathways and can influence the gene expression at epigenetic level, involving effects that probably are due to early life exposure. They show positive health effects on several diseases, especially in the prevention of coronary heart and neurological diseases, hormone-related cancers, osteoporosis, and postmenopausal symptoms.

METHODS

We have performed a critical evaluation of available literature trough a structured search of bibliographic databases about isoflavones health promoting properties, risk assessment and mechanisms of action. In addition, we supplied useful information on their biochemical properties, sources and bioavailability.

RESULTS

Although these molecules have been the subjects of numerous researches, their role for the wellness of the human organism remains controversial. Moreover, there are substantial inconsistencies between the results obtained by epidemiologic studies conducted on Eastern population, which found high health promoting properties, and Western clinical trials, which found much less positive effects.

CONCLUSION

Further epidemiologic studies and well-designed prospective human studies are to determine the beneficial effects of isoflavones exposure, as well as establishing its safe therapeutic.

Synthesis of Isoflavones by Tandem Demethylation and Ring-Opening/Cyclization of Methoxybenzoylbenzofurans

The unexpected conversion of benzoylbenzofurans into isoflavones through an intramolecular cascade that involves deprotection and ring-opening/cyclization is described. This was discovered in an investigation of the possible transformation of benzoylbenzofurans into coumaronochromones. This route affords isoflavones in two major steps from acetophenones and benzoquinones. The transformation was validated by synthesizing differently substituted isoflavone derivatives and further applied to a concise synthesis of a potential anticancer lead compound, glaziovianin A (1).

Cytotoxic polyphenolic compounds from Lespedeza bicolor stem bark

Four new pterocarpans (6aR,11aR)-6a,11a-dihydrolespedezol A₂ (2), (6aR,11aR)-2-isoprenyl-6a,11a-dihydrolespedezol A₂ (3), (6aR,11aR,3'R)-6a,11a-dihydrolespedezol A₃ (4), (6aR,11aR,3'S)-6a,11a-dihydrolespedezol A₃ (5) and one new stilbenoid with 1,2-diketone fragment named bicoloketone (6) along with one previously known pterocarpen lespedezol A₂ (1) have been isolated from Lespedeza bicolor stem bark using multistage column chromatography on polyamide and silica gel. The structures of the isolated polyphenolic compounds were determined by spectroscopic methods. The absolute configurations of 4 and 5 were determined by comparison of their electronic circular dichroism (ECD) spectra obtained experimentally and the spectra calculated using time-dependent density functional theory (TDDFT). The isolated compounds exhibited a moderate DPPH scavenging effect and ferric reducing power compared to the reference antioxidant quercetin. The cytotoxicity of compounds against three human cancer cell lines, HTB-19, Kyse-30, and HEPG-2, and two normal cell lines, RPE-1 and HEK-293, was tested using the MTT assay. Compound 3 showed the strongest cytotoxic activity against all cell lines (IC₅₀ 6.0-19.1 μM) compared with the positive control cisplatin. The other tested compounds possessed moderate cytotoxic activity against cancer cells.

Palladium-catalyzed coupling reactions on functionalized 2-trifluoromethyl-4-chromenone scaffolds. Synthesis of highly functionalized trifluoromethyl-heterocycles

The chromenone core is a ubiquitous group in biologically-active natural products and has been extensively used in organic synthesis. Fluorine derived compounds, including those with a trifluoromethyl group (-CF3), have shown enhanced biological activities in numerous pharmaceuticals compared with their non-fluorinated analogs. We have found that 2-trifluoromethyl chromenones can be readily functionalized in the 8- and 7-positions, providing chromenones cores of high structural complexity which are excellent precursors for numerous trifluoromethyl-heterocycles.

Isolation of naturally occurring novel isoflavonoids: an update

This review covers the literature concerning the isolation and identification of new naturally occurring isoflavonoids from Leguminosae and non-Leguminous species between 2012–2017.