Improved in vitro assays of superoxide anion and 1,1-diphenyl- 2-picrylhydrazyl (DPPH) radical-scavenging activity of isoflavones and isoflavone metabolites

Feature-Based Molecular Network-Assisted Cannabinoid and Flavonoid Profiling of Cannabis sativa Leaves and Their Antioxidant Properties

Cannabis sativa (C. sativa) leaves are rich in cannabinoids and flavonoids, which play important antioxidant roles. Since the environmental factors may influence the accumulation of antioxidants in herbal medicines, which affects their activity, this study aimed to investigate the correlation between the chemical composition of C. sativa leaves and their geographical origin and antioxidant activity. Firstly, a high-resolution mass spectrometry method assisted by semi-quantitative feature-based molecular networking (SQFBMN) was established for the characterization and quantitative analysis of C. sativa leaves from various regions. Subsequently, antioxidant activity analysis was conducted on 73 batches of C. sativa leaves, and a partial least squares regression (PLS) model was employed to assess the correlation between the content of cannabinoids and flavonoids in the leaves and their antioxidant activity. A total of 16 cannabinoids and 57 flavonoids were annotated from C. sativa, showing a significant regular geographical distribution. The content of flavonoid-C glycosides in Sichuan leaves is relatively high, and their antioxidant activity is also correspondingly high. However, the leaves in Shaanxi and Xinjiang were primarily composed of flavonoid-O glycosides, and exhibited slightly lower antioxidant activity. A significant positive correlation (p < 0.001) was found between the total flavonoids and cannabinoids and the antioxidant activity of the leaves, and two flavonoids and one cannabinoid were identified as significant contributors.

Gut microbial metabolites of dietary polyphenols and their potential role in human health and diseases

Polyphenols contribute as one of the largest groups of compounds among all the phytochemicals. Common sources of dietary polyphenols are vegetables, fruits, berries, cereals, whole grains, etc. Owing to their original form, they are difficult to get absorbed. Dietary polyphenols after undergoing gut microbial metabolism form bioaccessible and effective metabolites. Polyphenols and derived metabolites are all together a diversified group of compounds exhibiting pharmacological activities against cardiovascular, cancer, oxidative stress, inflammatory, and bacterial diseases. The formed metabolites are sometimes even more bioavailable and efficacious than the parent polyphenols. Studies on gut microbial metabolism of dietary polyphenols have introduced new approach for the use of polyphenol-rich food in the form of supplementary diet. This review provides insights on various aspects including classification of polyphenols, gut microbiota-mediated metabolism of polyphenols, chemistry of polyphenol metabolism, and pharmacological actions of gut microbial metabolites of polyphenols. It also suggests the use of polyphenols from marine source for the microbial metabolism studies. Till date, gut microbial metabolism of polyphenols from terrestrial sources is extensively studied as compared to marine polyphenols. Marine ecosystem is a profound but partially explored source of phytoconstituents. Among them, edible seaweeds contain high concentration of polyphenols, especially phlorotannins. Hence, microbial metabolism studies of seaweeds can unravel the pharmacological potential of marine polyphenol-derived metabolites.

The antioxidant and antidiabetic potentials of polyphenolic-rich extracts of Cyperus rotundus (Linn.)

In this study, the rhizome of Cyperus rotundus L was investigated for its antioxidant and antidiabetic effects using in vitro and in silico experimental models. Its crude extracts (ethyl acetate, ethanol and aqueous) were screened in vitro for their antioxidant activity using ferric-reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH), as well as their inhibitory effect on α-glucosidase enzyme. Subsequently, the extracts were subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis to elucidate their possible bioactive compounds. Furthermore, computational molecular docking of selected phenolic compounds was conducted to determine their mode of α-glucosidase inhibitory activity. The aqueous extract displayed the highest level of total phenolic content and significantly higher scavenging activity in both FRAP and DPPH assays compared to ethyl acetate and ethanol extracts. In FRAP and DPPH assays, IC₅₀ values of aqueous extract were 448.626 µg/mL and 418.74 µg/mL, respectively. Aqueous extract further presented higher α-glucosidase inhibitory activity with an IC₅₀ value of 383.75 µg/mL. GC-MS analysis revealed the presence of the following phenolic compounds: 4-methyl-2-(2,4,4-trimethylpentan-2-yl) phenol, Phenol,2-methyl-4-(1,1,3,3-tetramethylbutyl)- and 1-ethoxy-2-isopropylbenzene. Molecular docking study revealed 1-ethoxy-2-isopropylbenzene formed two hydrogen bonds with the interacting residues in the active site of α-glucosidase enzyme. Furthermore, 4-methyl-2-(2,4,4-trimethylpentan-2-yl) phenol had the lowest binding energy inferring the best affinity for α-glucosidase active site. These results suggest the possible antioxidant and antidiabetic potential of Cyperus rotundus.Communicated by Ramaswamy H. Sarma.

Daidzein supplementation improved fecundity in sows via modulation of ovarian oxidative stress and inflammation

Adequate ovarian hormones secretion is essential for pregnancy success. Oxidative damage and following inflammation can destroy the ovarian normal function in mammals. Daidzein (DAI) is a classical isoflavonic phytoestrogen with specific oestrogenic activity. This study aimed to explore the effects of daidzein supplementation on fertility and ovarian characteristics of sows through biochemical analysis and RNA-seq technology. Twelve multiparous Yorkshire × Landrace sows were randomly divided into CON and DAI groups. We found that DAI increased total number of embryos as well as P4 and E2 levels of serum. DAI not only elevated the activities of T-AOC and GSH-Px, but also tended to decrease the content of MDA and IL-6 in the serum. In ovary, RNA-Seq identified 237 differentially expressed genes (DEGs), and GO analysis showed that these DEGs were linked to functions associated with immune dysfunction. Moreover, STRING analysis demonstrated that most interacting nodes were TLR-4, LCP2, and CD86. Furthermore, DAI decreased the content of MDA, IL-1β, IL-6, and TNF-α, and increased the activities of T-AOC and CAT in ovarian tissue. Interestingly, a partial mantel correlation showed that T-AOC was the strongest correlation between the ovarian dataset and selected DEGs. Additionally, DAI supplementation not only increased the protein expressions of Nrf2, HO-1, and NQO1, but also decreased the protein expressions of TLR-4, p-NFκB, p-AKT, and p-IκBα. Altogether, our results indicated that DAI could ameliorate ovarian oxidative stress and inflammation in sows, which might be mediated by suppressing the TLR4/NF-κB signaling pathway and activating the Nrf2/HO-1 signaling pathway.

Fermentation of soymilk by Lactobacillus acidipiscis isolated from Chinese stinky tofu capable of efficiently biotransforming isoflavone glucosides to dihydrodaidzein and dihydrogenistein

BACKGROUND

The soy isoflavone microbial metabolites dihydrodaidzein (DHD), dihydrogenistein (DHG), equol and 5-hydroxy-equol are generally more biologically active than their precursors daidzein and genistein. Bacteria responsible for isoflavone metabolism have been isolated and identified. Fermented soymilk is a potential functional food; however, there are few lactic acid bacteria capable of metabolizing soy isoflavones.

RESULTS

A newly isolated Gram-positive facultative anaerobic bacterium, which was named Lactobacillus acidipiscis HAU-FR7, was isolated from the traditional Chinese fermented soy product 'stinky tofu'. Bacterium strain HAU-FR7 can grow under aerobic conditions and can also convert most of the daidzin and genistin in soymilk into DHD and DHG, respectively. The concentrations of DHD and DHG produced were 183 and 134 μmol L^-1 , respectively, after fermentation for 24 h. Strain HAU-FR7 does not produce the biogenic amines cadaverine, putrescine, histamine or tyramine, and an antibiotic susceptibility test showed that HAU-FR7 is sensitive to nine of the ten tested antibiotics, except for vancomycin. Moreover, the 1,1-diphenyl-2- picrylhydrazyl free radical scavenging capacity of soymilk fermented with HAU-FR7 was significantly higher than that of unfermented soymilk.

CONCLUSION

A facultative anaerobic lactic acid bacterium, designated Lactobacillus acidipiscis HAU-FR7, is capable of reducing the soy isoflavone glucosides daidzin and genistin in soymilk to DHD and DHG efficiently, even in the presence of atmospheric oxygen. The biotransformation activity of HAU-FR7 grown in soymilk is higher than that in de Man-Rogosa-Sharpe liquid culture medium. © 2022 Society of Chemical Industry.

Production of indole and hydrogen sulfide by the oxygen-tolerant mutant strain Clostridium sp. Aeroto-AUH-JLC108 contributes to form a hypoxic microenvironment

In this study, the oxygen-tolerant mutant strain Clostridium sp. Aeroto-AUH-JLC108 was found to produce indole when grown aerobically. The tnaA gene coding for tryptophanase responsible for the production of indole was cloned. The tnaA gene from Aeroto-AUH-JLC108 is 1677 bp and has one point mutation (C36G) compared to the original anaerobic strain AUH-JLC108. Phylogenetic analyses based on the amino acid sequence showed significant homology to that of TnaA from Flavonifractor. Furthermore, we found that the tnaA gene also exhibited cysteine desulfhydrase activity. The production of hydrogen sulfide (H₂S) was accompanied by decrease in the amount of the dissolved oxygen in the culture medium. Similarly, the amount of indole produced by strain Aeroto-AUH-JLC108 obviously decreased the oxidation-reduction potential (ORP) in BHI liquid medium. The results demonstrated that production of indole and H₂S helped to form a hypoxic microenvironment for strain Aeroto-AUH-JLC108 when grown aerobically.

Extraction Optimization, UHPLC-Triple-TOF-MS/MS Analysis and Antioxidant Activity of Ceramides from Sea Red Rice Bran

As a new type of salt-tolerant rice, sea red rice contains more minerals, proteins, and lipid compounds, and, in particular, its by-product rice bran may be used to replace other commercial rice brans as the main source of ceramides (Cers). However, the extraction rate of Cers is generally low, and it is crucial to seek an efficient extraction method. This study optimized the ultrasonic-assisted extraction of Cers from sea red rice bran using response surface methodology (RSM) and obtained a Cers yield of 12.54% under optimal conditions involving an extraction temperature of 46 °C, an extraction time of 46 min, and a material–to-liquid ratio of 5 g/mL. The Cers content in sea red rice bran was preliminarily analyzed using thin-layer chromatography, and the Cers content was determined via UHPLC-Triple-TOF-MS/MS after purification and separation using silica column chromatography. Forty-six different types of Cers were identified in sea red rice bran, of which Cer 18:0/24:0 (2OH), Cer 18:0/26:0, Cer 18:0/26:0 (2OH), and Cer 18:0/24:0 accounted for 23.66%, 17.54%, 14.91%, and 11.96%. Most of the Cers structures were mainly composed of sphingadienine. A biological activity assay indicated that Cers extracted from sea red rice bran had significant antioxidant and anti-aging properties. These findings indicate that the extracted Cers show great potential for applications in the cosmetic and pharmaceutical industries.

Synthesis and biological evaluation of 3-arylbenzofuranone derivatives as potential anti-Alzheimer's disease agents

Multi-target drugs can better address the cascade of events involved in oxidative stress and the reduction in cholinergic transmission that occur in Alzheimer’s disease than cholinesterase inhibitors alone. We synthesised a series of 3-arylbenzofuranone derivatives and evaluated their antioxidant activity, cholinesterase inhibitory activity, and monoamine oxidase inhibitory activity. 3-Arylbenzofuranone compounds exhibit good antioxidant activity as well as selective acetylcholinesterase inhibitory activity. The IC₅₀ value of anti-acetylcholinesterase inhibition of Compound 20 (0.089 ± 0.01 μM) is similar to the positive drug donepezil (0.059 ± 0.003 μM). According to the experimental results, Compounds 7, 13 show a certain effect in the in vitro evaluation performed and have the potential as drug candidates for the treatment of Alzheimer’s disease.

Selenium-Nanoparticles-Loaded Chitosan/Chitooligosaccharide Microparticles and Their Antioxidant Potential: A Chemical and In Vivo Investigation

Selenium nanoparticles (SeNPs) have attracted attention due to their favorable properties, unique bioactivities, and potential for use in nutritional supplements and nanomedicine applications. However, the application of SeNPs in the clinic has been greatly hindered by their poor stability, and their potential to protect against alcohol-induced oxidative stress has not been fully investigated. Herein, SeNPs were synthesized in the presence of chitosan (CS) or chitooligosaccharide (COS), and a mixture of SeNPs, CS, and COS was spray-dried to prepare selenium-nanoparticles-loaded chitosan/chitooligosaccharide microparticles (SeNPs-CS/COS-Ms). Their physicochemical properties, including morphology, elemental state, size distribution, surface potential, and characteristic structure, were investigated. The release of SeNPs from the vehicle and the free radical scavenging ability of SeNPs-CS/COS-Ms were also studied. Furthermore, the safety of SeNPs-CS/COS-Ms and their antioxidant activity against alcohol were evaluated in mice. The results indicate that SeNPs-CS/COS-Ms, with a novel structure characterized by their smooth or wrinkled surface, hollow core, and COS body filled with SeNPs-CS nanobeads, were able to release SeNPs and scavenge DPPH and superoxide anion radicals. SeNPs-CS/COS-Ms were found to be much safer than selenite, and they might protect mice from ethanol-induced oxidative stress by reducing lipid and protein oxidation and by boosting glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT). In conclusion, SeNPs-CS/COS-Ms offer a new way to develop stable SeNPs with higher efficacy and better biosafety, and the antioxidant potential of SeNPs-CS/COS-Ms against ethanol deserves further development.

Profiling the metabolites of astrapterocarpan in rat hepatic 9000g supernatant

Astrapterocarpan (AP) is a bioactive constituent of Astragali Radix and was selected as a model compound for investigating the in vitro metabolism of pterocarpans in this study. Its in vitro metabolism was conducted by incubation with rat hepatic 9000g supernatant (S9) in the presence of an NADPH-generating system. At first, four compounds were isolated and their structures were elucidated as 6a-hydroxy-AP (M1), astrametabolin I [M2, 1a-hydroxy-9, 10-dimethoxy-pterocarp-1(2), 4-diene-3-one], 9-demethyl-AP (M3, nissolin) and 4-methoxy-astraisoflavan (M4, 7, 2'dihydroxy-4, 3', 4'-trimethoxy-isoflavan) on the basis of NMR data, respectively. Among them, M1, M2 and M4 were new compounds. Next, the metabolite profile of AP in rat hepatic S9 was obtained via HPLC-DAD-ESI-IT-TOF-MSⁿ, and 40 new metabolites were tentatively identified. These newly identified metabolites included 9 monohydroxylated metabolites, 1 demethylated metabolite, 7 demethylated and monohydroxylated metabolites, 4 dihydroxylated metabolites, 1 hydration metabolite, 1 didemethylated metabolite, 2 glucosylated metabolites, 1 monohydroxylated and dehydrogenated metabolite, 2 monohydroxylated and demethylated and dehydrogenated metabolites, 2 dimerized metabolites, 3 dimerized and monohydroxylated metabolites, 2 dimerized and didemethylated metabolites, and 5 dimerized and demethylated metabolites. Finally, the major metabolic reactions of AP in rat hepatic S9 were summarized and found to be hydroxylation, demethylation, dimerization, hydration, and dehydrogenation. More importantly, the biotransformation from AP to M2 and the dimerization of AP by incubation with hepatic S9 were reported for the first time. In conclusion, this is the first report on the metabolism of a pure pterocarpan in animal tissues, and these findings will provide a solid basis for further studies on the metabolism of other pterocarpans.

Isolation and identification of an isoflavone reducing bacterium from feces from a pregnant horse

The aim of this research was to isolate bacteria capable of biotransforming daidzein from fresh feces from pregnant horses. A Hungate anaerobic roller tube was used for anaerobic culture. Single colonies were picked at random and incubated with daidzein. High performance liquid chromatography was used to detect whether the isolated bacteria were able to biotransform the substrate. A strain capable of reducing daidzein was selected and characterized using sequence analysis of 16S rDNA, and a phylogenetic tree was constructed. The morphological physiological and biochemical characteristics of the strain were investigated. A facultative anaerobic, Gram-positive bacterium capable of converting daidzein to dihydrodaidzein was isolated and named HXBM408 (MF992210). A BLAST search of HXBM408's 16S rDNA sequence against the GenBank database suggested that the strain has 99% similarity with Pediococcus acidilactici strain DSM (NR042057). The morphological, physiological, and biochemical characteristics of HXBM408 are very similar to those of Pediococcus. Based on these characteristics, the strain was identified as Pediococcus acidilactici. The bacterial strain HXBM408 isolated from the feces of pregnant horses was able to reduce the isoflavone daidzein to dihydrodaidzein.

S-equol glucuronidation in liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice

S-equol, an active metabolite of the soy isoflavone daidzein, is mainly metabolized into glucuronide(s) by UDP-glucuronosyltransferase (UGT) enzymes in mammals. In the present study, S-equol glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis. CL_int values for 7- and 4'-glucuronidation by liver microsomes were higher than those by intestinal microsomes in all species. CL_int values for total glucuronidation (sum of 7- and 4'-glucuronidation) were rats (7.6) > monkeys (5.8) > mice (4.9) > dogs (2.8) > humans (1.0) for liver microsomes, and rats (9.6) > mice (2.8) > dogs (1.3) ≥ monkeys (1.2) > humans (1.0) for intestinal microsomes, respectively. Regarding regioselective glucuronidation by liver and intestinal microsomes, CL_int values were 7-glucuronidation > 4'-glucuronidation for humans, monkeys, dogs, and mice, and 4'-glucuronidation > 7-glucuronidation for rats. These results suggest that the metabolic abilities of UGT enzymes toward S-equol in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice.

Integrating chemical similarity and bioequivalence: A pilot study on quality consistency evaluation of dispensing granule and traditional decoction of Scutellariae Radix by a totality-of-the-evidence approach

There is an increasing focus on the quality consistency evaluation of dispensing granule in traditional Chinese medicines (TCMs). According to the guideline from Chinese Pharmacopoeia Commission, the substantial equivalence of dispensing granule and traditional decoction should be determined, and the chromatographic fingerprint has been recommended as a comprehensive qualitative approach to assess the quality consistency between dispensing granule and traditional decoction. However, a high-degree chemical similarity does not equal a bioequivalence. Attempting to realize the quality evaluation by integrating chemical consistency and bioequivalence, we herein proposed a totality-of-the-evidence approach based on clustering analysis and equivalence evaluation taking the dispensing granule and traditional decoction of Scutellariae Radix (SR) as a typical case. Chemical fingerprints were developed by high performance liquid chromatography coupled with photodiode array detector and quadrupole time-of-flight mass spectrometry (HPLC-PDA/QTOF-MS). Subsequently, a feature selection strategy, integrated linear and nonlinear correlation analysis, was carried out to assess the correlation between chemical profiles and biological activities. Finally, quality consistency between the dispensing granule and the traditional decoction was determined by bioactive marker-guided hierarchical clustering analysis (HCA), k-means clustering method and bioequivalence evaluation. The available evidence suggested that not all the dispensing granule of SR were sufficiently similar to the traditional decoction. This study provides an applicable methodology for quality consistency evaluation of dispensing granule and traditional decoction in TCMs.

Bioactivity of dietary polyphenols: The role of metabolites

A polyphenol-rich diet protects against chronic pathologies by modulating numerous physiological processes, such as cellular redox potential, enzymatic activity, cell proliferation and signaling transduction pathways. However, polyphenols have a low oral bioavailability mainly due to an extensive biotransformation mediated by phase I and phase II reactions in enterocytes and liver but also by gut microbiota. Despite low oral bioavailability, most polyphenols proved significant biological effects which brought into attention the low bioavailability/high bioactivity paradox. In recent years, polyphenol metabolites have attracted great interest as many of them showed similar or higher intrinsic biological effects in comparison to the parent compounds. There is a huge body of literature reporting on the biological functions of polyphenol metabolites generated by phase I and phase II metabolic reactions and gut microbiota-mediated biotransformation. In this respect, the review highlights the pharmacokinetic fate of the major dietary polyphenols (resveratrol, curcumin, quercetin, rutin, genistein, daidzein, ellagitannins, proanthocyanidins) in order to further address the efficacy of biometabolites as compared to parent molecules. The present work strongly supports the contribution of metabolites to the health benefits of polyphenols, thus offering a better perspective in understanding the role played by dietary polyphenols in human health.

Isolation and Characterization of a Human Intestinal Bacterium Eggerthella sp. AUH-JLD49s for the Conversion of (-)-3'-Desmethylarctigenin

Arctiin is the most abundant bioactive compound contained in the Arctium lappa plant. In our previous study, we isolated one single bacterium capable of bioconverting arctigenin, an aglycone of arctiin, to 3'-desmethylarctigenin (3'-DMAG) solely. However, to date, a specific bacterium capable of producing other arctiin metabolites has not been reported. In this study, we isolated one single bacterium, which we named Eggerthella sp. AUH-JLD49s, capable of bioconverting 3'-DMAG under anaerobic conditions. The metabolite of 3'-DMAG by strain AUH-JLD49s was identified as 3'-desmethyl-4'-dehydroxyarctigenin (DMDH-AG) based on electrospray ionization mass spectrometry (ESI-MS) and ¹H and ¹³C nuclear magnetic resonance spectroscopy. The bioconversion kinetics and bioconversion capacity of strain AUH-JLD49s were investigated. In addition, the metabolite DMDH-AG showed an inhibitory effect on cell growth of human colon cancer cell line HCT116 and human breast cancer cell line MDA-MB-231.

Dietary phytoestrogens, intestinal microflora and human health

With the growth of age, the amount of estrogens produced by the human body will get less and less. Studies have shown that estrogen deficiency may cause many kinds of diseases, such as cardiovascular diseases, osteoporosis, and syndrome of menopause. Estrogens are also distributed extensively in numerous types of plants. Since there is a trace amount of natural estrogen in plants, our body can achieve continuous phytoestrogen supplementation while our health will not be influenced or damaged by the absorbed phytoestrogens in diets. After being absorbed, the phytoestrogens in diets may be converted by intestinal microflora to different metabolites with higher estrogenic activity. This review summarizes the types and distributions of phytoestrogens in diets, their metabolism, metabolites and bioactivities, with an aim to provide some guidelines for further study and utilization of microbial biotransforming metabolites of phytoestrogens.

Comparison of chemical profiling and antioxidant activities of fruits, leaves, branches, and flowers of Citrus grandis 'Tomentosa'

Citrus grandis 'Tomentosa' (CGT) is particularly cultivated in China and widely used in health foods. In this study, the chemical profiles of different parts of CGT were comprehensively compared by rapid resolution liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry method. A total of 22 compounds were identified and two C-glucosyl flavones were found for the first time in CGT. Four main constituents (rhiofolin, naringin, meranzin hydrate, and isoimperatorin) in different parts of CGT were simultaneously determined. Overall, the contents of the four main compounds decreased with the ripening process. In parallel, the antioxidant activities of their extracts were also evaluated by three assays (2,2'-azinobis(3-ethylbenzthiazolinesulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power), and the results indicated a similar tendency: small fruit > flower ∼ medium fruit > large fruit > leaf ∼ branch. The results obtained in the present work may provide useful information for future utilization of CGT.

Study on human intestinal bacterium Blautia sp. AUH-JLD56 for the conversion of arctigenin to (-)-3'-desmethylarctigenin

Arctium lappa L. (A. lappa) is a popularly used vegetable as well as herbal medicine. Human intestinal microflora was reported to convert arctiin, the lignan compound with highest content in the dried fruits of Arctium lappa, to a series of metabolites. However, the specific bacterium responsible for the formation of 3'-desmethylarctigenin (3'-DMAG), the most predominant metabolite of arctiin by rat or human intestinal microflora, has not been isolated yet. In the present study, we isolated one single bacterium, which we named Blautia sp. AUH-JLD56, capable of solely biotransforming arctiin or arctigenin to (-)-3'-DMAG. The structure of the metabolite 3'-DMAG was elucidated by electrospray ionization mass spectrometry (ESI-MS) and (1)H and (13)C nuclear magnetic resonance spectroscopy. The biotransforming kinetics and maximum biotransforming capacity of strain AUH-JLD56 was investigated. In addition, the metabolite 3'-DMAG showed significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity than that of the substrate arctigenin at the concentrations tested.

Transport mechanisms for soy isoflavones and microbial metabolites dihydrogenistein and dihydrodaidzein across monolayers and membranes

Isoflavone data concerning the metabolism and permeability on intestinal epithelial cells are scarce, particularly for microbial isoflavone metabolites. This study evaluates the absorption mechanisms for the isoflavones, genistein and daidzein, and their microbial metabolites, dihydrogenistein (DHG) and dihydrodaidzein (DHD). The permeability characteristics of isoflavones were compared by using the Caco-2 human colon adenocarcinoma cell line for a parallel artificial membrane permeability assay, and comparing their physicochemical properties. The data suggest that genistein, DHG and DHD were efficiently transported by passive diffusion according to the pH-partition hypothesis. Genistein was conjugated by phase II metabolizing enzymes and acted as a substrate of the breast cancer resistance protein (BCRP). Daidzein was not conjugated but did act as a substrate for BCRP, multidrug resistance-associated proteins, and P-glycoprotein. In contrast, DHG and DHD were markedly more permeable than their parent isoflavones; they were therefore difficult to transport by the efflux effect, and glucuronidation/sulfation was limited by the flux time.

Synthesis, anticonvulsant, antioxidant and binding interaction of novel N-substituted methylquinazoline-2,4(1H,3H)-dione derivatives to bovine serum albumin: a structure-activity relationship study

A novel class of N-substituted glycosmicine derivatives was synthesized, and their anticonvulsant, antioxidant activity and interaction with bovine serum albumin (BSA) were evaluated. The synthesized compounds 4a-j were examined for anticonvulsant activity by maximal electroshock induced seizures (MESs) test and their neurotoxic effects were determined by rotorod test in mice. The structure-activity relationships (SARs) of these compounds were also investigated. Compounds 4d, 4g, 4i and 4j were found to have good protective effect from seizure. The in vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assay. The interaction between novel N-substituted methylquinazoline-2,4(1H,3H)-dione (NMQ) and BSA was analyzed by fluorescence and ultraviolet spectroscopy at 304K under simulative physiological conditions. BSA fluorescence quenched by NMQ is discussed according to the Stern-Volmer equation. The binding constant and binding sites of NMQ with BSA were calculated. According to Forster non-radiation energy transfer theory, the binding distance (r) between NMQ and BSA was calculated.

A new daidzein derivative from endophytic Streptomyces sp. YIM 65408

A new daidzein derivative, 1″-O-methyl-8-hydroxymethyl-daidzein (1) was isolated from Streptomyces sp. YIM 65408 in soybean powder containing medium. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HR-ESI-MS spectroscopic analyses. The radical-scavenging activity and cytotoxicity of compound 1 were also investigated, and 1 was found to be more active than daidzein in the 2,2-diphenyl-1-picrylhydrazyl method with IC50 at 0.60 mmol/L, but no cytotoxicity of 1 against HL-60, SMMC-7721, A-549, MCF-7 and SW480 cell lines was shown. The possible biosynthesis pathway from daidzein (2) to compound 1 was proposed.

Evaluation of biological activities of a groundnut (Apios americana Medik) extract containing a novel isoflavone

Groundnut (Apios americana Medik) contains a novel isoflavone, genistein-7-O-gentiobioside. In the present study, we examined the biological activities of an alcohol extract of groundnut containing genistein-7-O-gentiobioside as the main component. Although the groundnut extract by itself did not show antioxidative activity, it drove the antioxidative system in cells. Pretreatment of human breast carcinoma MCF-7 cells for 24 h with the groundnut extract and soybean isoflavone increased gene expression of heme oxygenase-1 (HO-1), a major antioxidative stress enzyme. These groundnut extract-treated cells showed antioxidative activity against free radicals derived from a radical initiator. Pretreatment of cells with 100 μg/mL groundnut extract prevented the depletion of glutathione by the radical initiator; however, treatment with 100 μg/mL of soybean isoflavone injured the cell membrane, indicating that glutathione might be released to the extracellular environment. These results suggest that the groundnut extract had isoflavone-like activity. Like soybean, groundnuts are a good source of isoflavones.

O-desmethylangolensin: the importance of equol's lesser known cousin to human health

The objective for this paper was to review human studies of O-desmethylangolensin (O-DMA) concentrations and of O-DMA producers compared with nonproducers in the context of results from in vitro studies. O-DMA is an intestinal bacterial metabolite of daidzein, an isoflavone compound observed to have phytoestrogenic properties. Not all individuals harbor bacteria capable of metabolizing daidzein to O-DMA, and individuals can be classified as O-DMA producers and nonproducers. O-DMA is less structurally similar to 17β-estradiol than its parent compound, daidzein; thus, it may exhibit different biological actions than daidzein. Evidence from in vitro studies suggests that O-DMA has several cancer-related biological actions. However, results from human metabolic studies and observational studies of disease risk suggest that these actions may not be physiologically relevant in vivo due to the amount and form (primarily glucuronide) of circulating O-DMA. Apart from circulating O-DMA concentrations, the underlying bacteria may have a distinct physiological role. Urinary excretion of O-DMA in humans is a marker of harboring intestinal bacteria capable of C-ring cleavage. Bacterial C-ring cleavage reactions are relevant to other phytochemicals that may exert biological actions in vivo that are stronger than the actions of O-DMA; thus, the role of the phenotype may extend beyond daidzein metabolism. There are a limited number of studies that have evaluated disease risk factors in relation to being an O-DMA producer, with mixed results. Further research evaluating disease risk in relation to the O-DMA-producer phenotype from the perspective of intestinal microbial composition is recommended.