Analysis of the metabolites of isorhamnetin 3-O-glucoside produced by human intestinal flora in vitro by applying ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry

Neurite Outgrowth-Promoting Compounds from the Petals of Paeonia lactiflora in PC12 Cells

Isorhamnetin-3-O-glucoside and astragalin, flavonol glucosides, were isolated from the petals of Paeonia lactiflora as neurite outgrowth-promoting compounds. Isoquercitrin, formed by demethylating the B ring of isorhamnetin-3-O-glucoside or by adding a hydroxyl group to the B ring of astragalin, was evaluated for neurite outgrowth-promoting activity and was compared with the activities of isorhamnetin-3-O-glucoside and astragalin. The activities of isorhamnetin, kaempferol, and quercetin, aglycones corresponding to isorhamnetin-3-O-glucoside, astragalin, and isoquercitrin, respectively, were also evaluated. Isorhamnetin-3-O-glucoside and astragalin showed much stronger neurite outgrowth-promoting activities than the activities of the other tested flavonoids. They exhibited relatively weak anti-oxidant activities and moderate AChE inhibitory activities compared to the activities of the other tested flavonoids. Isorhamnetin-3-O-glucoside and astragalin promoted morphological neurite outgrowth and the expression of neurofilaments induced by NGF in PC12 cells. Isorhamnetin-3-O-glucoside and astragalin might be candidate compounds as neural differentiation agents in peripheral nerves and functional food ingredients preventing cognitive decline.

Antibacterial Activity from Momordica charantia L. Leaves and Flavones Enriched Phase

Momordica charantia L. (Cucurbitaceae) is a plant known in Brazil as "melão de São Caetano", which has been related to many therapeutic applications in folk medicine. Herein, we describe antibacterial activities and related metabolites for an extract and fractions obtained from the leaves of that species. An ethanolic extract and its three fractions were used to perform in vitro antibacterial assays. In addition, liquid chromatography coupled to mass spectrometry and the molecular networking approach were used for the metabolite annotation process. Overall, 25 compounds were annotated in the ethanolic extract from M. charantia leaves, including flavones, terpenes, organic acids, and inositol pyrophosphate derivatives. The ethanolic extract exhibited low activity against Proteus mirabilis (MIC 312.5 µg·mL-1) and Klebsiella pneumoniae (MIC 625 µg·mL-1). The ethyl acetate phase showed interesting antibacterial activity (MIC 156.2 µg·mL-1) against Klebsiella pneumoniae, and it was well justified by the high content of glycosylated flavones. Therefore, based on the ethyl acetate phase antibacterial result, we suggest that M. charantia leaves could be considered as an alternative antibacterial source against K. pneumoniae and can serve as a pillar for future studies as well as pharmacological application against the bacteria.

Reducing the intestinal side effects of acarbose by baicalein through the regulation of gut microbiota: An in vitro study

Combination of dietary flavonoid-baicalein and acarbose reduces the risk that prediabetes will develop into type 2 diabetes mellitus; however, the mechanism underlying this effect has not been clarified. In this study, the in vitro culture conditions of intestinal microorganisms from prediabetic mice were optimized to increase over 30% similarity between in vitro cultured and fecal samples. Baicalein and acarbose alone and in combination, and their corresponding starch hydrolysate were assayed by the in vitro model. The results indicated that the combination of baicalein with acarbose decreased gas production by reducing the residual starch ratio in starch hydrolysate and decreasing the dosage of acarbose, and that reducing the relative abundance of gut bacteria correlated with gas production is the main mechanism. This study provided a theoretical foundation for the development of flavonoid dietary supplements to enhance the efficacy of oral hypoglycemic agents with fewer side effects and higher efficacy.

Tentatively Identified (UPLC/T-TOF-MS/MS) Compounds in the Extract of Saussurea costus Roots Exhibit In Vivo Hepatoprotection via Modulation of HNF-1α, Sirtuin-1, C/ebpα, miRNA-34a and miRNA-223

Saussurea costus is a plant traditionally used for the treatment of several ailments. Our study accomplished the UPLC/T-TOF-MS/MS analysis of a methanol extract of Saussurea costus roots (MESC), in addition to lipoidal matter determination and assessment of its in vivo hepatoprotective activity. In this study, we were able to identify the major metabolites in MESC rather than the previously known isolated compounds, improving our knowledge of its chemical constituents. The flavones apigenin, acacetin, baicalein, luteolin, and diosmetin, and the flavonol aglycones quercetin, kaempferol, isorhamnetin, gossypetin, and myricetin and/or their glycosides and glucuronic derivatives were the major identified compounds. The hepatoprotective activity of MESC was evaluated by measuring catalase activity using UV spectrophotometry, inflammatory cytokines and apoptotic markers using ELISA techniques, and genetic markers using PCR. Paracetamol toxicity caused a significant increase in plasma caspase 2, cytokeratin 18 (CK18), liver tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), miRNA-34a, and miRNA-223, as well as a significant decrease in liver catalase (CAT) activity and in the levels of liver nuclear factor 1α (HNF-1α), sirtuin-1, and C/ebpα. Oral pretreatment with MESC (200 mg/kg) showed a significant decrease in caspase 2, CK18, TNF-α, IL-6 and a significant increase in liver CAT activity. MESC decreased the levels of liver miRNA-34a and miRNA-223 and induced HNF-1α, sirtuin-1, and C/ebpα gene expression. The histological examination showed a significant normalization in rats pretreated with MESC. Our findings showed that Saussurea costus may exert a potent hepatoprotective activity through the modulation of the expression of cellular cytokines, miRNA-34a, and miRNA-223.

Revealing the Mechanism of Huazhi Rougan Granule in the Treatment of Nonalcoholic Fatty Liver Through Intestinal Flora Based on 16S rRNA, Metagenomic Sequencing and Network Pharmacology

Background: The incidence of Nonalcoholic Fatty Liver (NAFL) is increasing year by year, growing evidence suggests that the intestinal flora plays a causative role in NAFL. Huazhi Rougan Granule (HRG) is commonly used in the clinical treatment of NAFL. It is reported that it can reduce lipids and protect the liver, but no research has confirmed whether the drug's effect is related to the intestinal flora. Therefore, we investigated whether the effect of HRG is related to the regulation of intestinal flora to further explore the mechanism of HRG in the treatment of NAFL through intestinal flora. Methods: In this study, C57BL/6J mice were fed a high-fat diet for 8 weeks, and the high-fat diet plus HRG or polyene phosphatidylcholine capsules were each administered by gavage for 4 weeks. High-throughput sequencing, network pharmacology, and molecular docking were used to explore the mechanism of HRG in the treatment of NAFL through intestinal flora. Results: HRG treatment can reduce body weight gain, lipid accumulation in liver and lipogenesis and reduce serum biochemical indexes in high-fat-fed mice. Analysis of intestinal flora showed that HRG changed the composition of intestinal flora, which was characterized by a decrease in the Firmicutes/Bacteroidetes ratio. Moreover, the species distribution was significantly correlated with AKP, HDL-C, and TG. Metagenetic analysis showed that HRG altered the functional composition and functional diversity of microorganisms, which was mainly characterized by an increase in the abundance of metabolic pathways. The network pharmacology results show that the mechanism of HRG in the treatment of NAFL through intestinal flora is mainly reflected in the biological process of gene function and related to infectious diseases, immune systems, and signal transduction pathways, such as cytokine-cytokine receptor interaction, Chagas disease, IL-17 signaling pathway and other signaling pathways. Conclusion: These results strongly suggest that HRG may alleviate NAFL by preventing IFD.

Novel Catabolic Pathway of Quercetin-3-O-Rutinose-7-O-α-L-Rhamnoside by Lactobacillus plantarum GDMCC 1.140: The Direct Fission of C-Ring

Lychee pulp phenolics (LPP) is mainly catabolized in the host colon, increasing the abundances of Bacteroides and Lactobacillus. Herein, five selected gut microbial strains (Bacteroides uniformis, B. thetaiotaomicron, Lactobacillus rhamnosus, L. plantarum, and L. acidophilus) were separately incubated with LPP to ascertain the specific strains participating in phenolic metabolism and the corresponding metabolites. The results indicated that B. uniformis, L. rhamnosus, and L. plantarum were involved in LPP utilization, contributing to 52.37, 28.33, and 45.11% of LPP degradation after 48 h fermentation, respectively. Unprecedentedly, the metabolic pathway of the major phenolic compound quercetin-3-O-rutinose-7-O-α-L-rhamnoside by L. plantarum, appeared to be the direct fission of C-ring at C2–O1 and C3–C4 bonds, which was proved from the occurrence of two substances with the deprotonated molecule [M–H]⁻ ion at m/z 299 and 459, respectively. Meanwhile, it was fully confirmed that B. uniformis participated in the catabolism of isorhamnetin glycoside and procyanidin B2. In the B. uniformis culture, kaempferol was synthesized through dehydroxylation of quercetin which could be catabolized into alphitonin by L. rhamnosus. Furthermore, LPP metabolites exerted higher antioxidant activity than their precursors and gave clues to understand the interindividual differences for phenolic metabolism by gut microbiota.

The anti-hyperuricemic effects of green alga Enteromorpha prolifera polysaccharide via regulation of the uric acid transporters in vivo

A novel polysaccharide obtained from Enteromorpha prolifera (EPP) was purified through diethylaminoethyl cellulose-52 and Sephadex G-75 chromatography. Fourier transform infrared spectroscopy, high-performance liquid chromatography, and nuclear magnetic resonance (NMR) spectroscopy were employed to analyse the structure of EPP. It mainly comprised rhamnose, glucuronic acid, galactose, arabinose, and xylose at a molar ratio of 20.45:12.74:10.99:5.84:1.95, and its average molecular weight was 46.56 kDa. The seven major glycosidic residues identified by NMR were as follows: →2)-α-L-Araf-(1→, →2)-α-L-Rhap-(1→, →4)-α-L-Rhap-(1→, →2,6)-β-D-Galp-(1→, →4)-β-D-GlcpA-(1→, →3,4)-β-D-GlcpA-(1→, and →4)-β-Xylp-(1→. The effect of EPP on hyperuricemic mice was determined by analysing correlative general physical parameters, renal histopathology, renal gene expressions, and gut microbiome. EPP significantly reduced serum uric acid (UA), serum blood urea nitrogen, serum xanthine oxidase (XOD), and hepatic XOD as well as improved histological parameters in hyperuricemic mice. Furthermore, mRNA and protein expression analyses showed the upregulation of UA excretion genes such as ABCG2, OAT1, and NPT1 and downregulation of UA resorption gene URAT1. Moreover, EPP maintained the stability of the intestinal flora and confirmed that Parasutterella is closely related to the regulation of hyperuricemia. This study is the first to demonstrate the anti-hyperuricemic activity of EPP and highlight its therapeutic potential for hyperuricemia-related diseases.

Chemical profiling and multicomponents quantitative analysis of Panzerina lanata by ultra-fast liquid chromatography with tandem mass spectrometry

Panzerina lanata is a Chinese medicine with the bioactivity of detumescence and detoxification. In this study, novel qualitative and quantitative methods were established by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry and ultra-high-performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry, respectively. As a result, 20 compounds were identified or tentatively characterized including flavonoids, organic acids, alkaloids, and lignans, five of which were identified for the first time based on the reference standards. The quantitative approach exhibited good linearity (R²  > 0.995), precision (RSDs < 4.97%), stability (RSDs < 4.77%), and recovery (96.04-104.14%). Afterward, this method was implemented to determine 11 flavonoids in four batches of P. lanata. Among them, seven compounds were quantified for the first time. Narcissin was abundant in each batch of P. lanata (average of 10.890-14.230 mg/g) with the highest quantities. The results provide valuable information for quality evaluation.

In Vitro Studies to Assess the α-Glucosidase Inhibitory Activity and Insulin Secretion Effect of Isorhamnetin 3-O-Glucoside and Quercetin 3-O-Glucoside Isolated from Salicornia herbacea

In this study, we examined the effect of ethanolic extract of Salicornia herbacea (ESH), isorhamnetin 3-O-glucoside (I3G), quercetin 3-O-glucoside (Q3G), quercetin, and isorhamnetin on α-glucosidase activity and glucose-stimulated insulin secretion (GSIS) in insulin-secreting rat insulinoma (INS-1) cells. A portion of the ethyl acetate fraction of ESH was chromatographed on a silica gel by a gradient elution with chloroform and methanol to provide Q3G and I3G. ESH, Q3G, and quercetin inhibited α-glucosidase activity, and quercetin (IC50 value was 29.47 ± 3.36 μM) inhibited the activity more effectively than Q3G. We further demonstrated that ESH, Q3G, quercetin, I3G, and isorhamnetin promote GSIS in INS-1 pancreatic β-cells without inducing cytotoxicity. Among them, I3G was the most effective in enhancing GSIS. I3G enhanced the phosphorylation of total extracellular signal-regulated kinase (ERK), insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, and activated pancreatic and duodenal homeobox-1 (PDX-1), which are associated with insulin secretion and β-cell function. As components of ESH, Q3G has the potential to regulate blood glucose by inhibiting α-glucosidase activity, and I3G enhances the insulin secretion, but its bioavailability should be considered in determining biological importance.

Health promoting properties and sensory characteristics of phytochemicals in berries and leaves of sea buckthorn (Hippophaë rhamnoides)

Sea buckthorn (Hippophaë rhamnoides L., SB), as a multi-functional plant, is widely grown in Asia, Europe and Canada. The berries and leaves of SB contain a diverse array of health-supporting phytochemicals, which are also related to the sensory qualities of berry and berry products. This review summarizes the biologically active key-compounds of the berries and leaves of SB, their health-promoting effects, as well as the contributions to the sensory quality of the berries. The target compounds consist of sugars, sugar derivatives, organic acids, phenolic compounds and lipophilic compounds (mainly carotenoids and tocopherols), which play an important role in anti-inflammatory and antioxidant functions, as well as in metabolic health. In addition, these compounds contribute to the orosensory qualities of SB berries, which are closely related to consumer acceptance and preference of the products. Studies regarding the bioavailability of the compounds and the influence of the processing conditions are also part of this review. Finally, the role of the sensory properties is emphasized in the development of SB products to increase utilization of the berry as a common meal component and to obtain value-added products to support human health.

Microbial Phenolic Metabolites: Which Molecules Actually Have an Effect on Human Health?

The role of gut microbiota in human health has been investigated extensively in recent years. The association of dysbiosis, detrimental changes in the colonic population, with several health conditions has led to the development of pro-, pre- and symbiotic foods. If not absorbed in the small intestine or secreted in bile, polyphenols and other food components can reach the large intestine where they are susceptible to modification by the microbial population, resulting in molecules with potentially beneficial health effects. This review provides an overview of studies that have detected and/or quantified microbial phenolic metabolites using high-performance liquid chromatography as the separation technique, followed by detection through mass spectrometry. Both in vitro experimental studies and human clinical trials are covered. Although many of the microbial phenolic metabolites (MPM) reported in in vitro studies were identified in human samples, further research is needed to associate them with clinical health outcomes.

Ophiopogon Polysaccharide Promotes the In Vitro Metabolism of Ophiopogonins by Human Gut Microbiota

Gut microbiota play an important role in metabolism of intake saponins, and parallelly, the polysaccharides deriving from herbal products possess effects on gut microbiota. Ophiopogonis Radix is a common Chinese herb that is popularly used as functional food in China. Polysaccharide and steroidal saponin, e.g., ophiopogonin, mainly ophiopogonin D (Oph-D) and ophiopogonin D' (Oph-D'), are the major constituents in this herb. In order to reveal the role of gut microbiota in metabolizing ophiopogonin, an in vitro metabolism of Oph-D and Oph-D' by human gut microbiota, in combination with or without Ophiopogon polysaccharide, was conducted. A sensitive and reliable UPLC-MS/MS method was developed to simultaneously quantify Oph-D, Oph-D' and their final metabolites, i.e., ruscogenin and diosgenin in the broth of microbiota. An elimination of Oph-D and Oph-D' was revealed in a time-dependent manner, as well as the recognition of a parallel increase of ruscogenin and diosgenin. Ophiopogon polysaccharide was shown to stimulate the gut microbiota-induced metabolism of ophiopogonins. This promoting effect was further verified by increased activities of β-D-glucosidase, β-D-xylosidase, α-L-rhamnosidase and β-D-fucosidase in the broth. This study can be extended to investigate the metabolism of steroidal saponins by gut microbiota when combined with other herbal products, especially those herbs enriched with polysaccharides.

UHPLC-Q-TOF-MS/MS method based on four-step strategy for metabolites of hinokiflavone in vivo and in vitro

Hinokiflavone (HF), belonging to biflavonoids, possesses excellent pharmacological activities, including anti-inflammatory, antioxidant and antitumor activity. Nevertheless, its metabolism in vivo (rats) and in vitro (rat liver microsomes and intestinal flora) is presently not characterized. In this study, ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) based on four-step strategy was a rapid method for the detection of HF metabolites. A total of 41 metabolites in vivo, 49 metabolites in vitro were characterized. It also verified that intestinal tract exceeds the liver in the biotransformation of HF. More significant, the main metabolic pathways for HF were mainly bio-transformed to various mono-flavone resulting from the rupture of connective CO bonds, which exhibited a large distinction with other biflavones. Noteworthily, glutamine conjugation and glycine conjugation were considered as unique metabolic pathways of HF. The information obtained from this study contributes to better understanding of pharmacological mechanism of HF.

Antibiotics may increase triazine herbicide exposure risk via disturbing gut microbiota

BACKGROUND

Antibiotics are commonly used worldwide, and pesticide is a kind of xenobiotic to which humans are frequently exposed. The interactive impact of antibiotics on pesticides has rarely been studied. We aim to investigate the effects of antibiotics on the pesticide exposure risk and whether gut microbiota altered by antibiotics has an influence on pesticide bioavailability. Furthermore, we explored the mechanisms of gut microbiota affecting the fate of pesticides in the host.

RESULTS

The oral bioavailability of triazine herbicides significantly increased in the rats treated with ampicillin or antibiotic cocktails. The antibiotic-altered gut microbiota directly influenced the increased pesticide bioavailability through downregulating hepatic metabolic enzyme gene expression and upregulating intestinal absorption-related proteins.

CONCLUSIONS

Antibiotics could increase the pesticide bioavailability and thereby may increase the pesticide exposure risk. The antibiotic-altered gut microbiota that could alter the hepatic metabolic enzyme gene expression and intestinal absorption-related proteome was a critical cause of the increased bioavailability. This study revealed an undiscovered potential health impact of antibiotics and reminded people to consider the co-exposed xenobiotics when taking antibiotics.

Degradation Kinetics of 6‴-p-Coumaroylspinosin and Identification of Its Metabolites by Rat Intestinal Flora

6‴-p-Coumaroylspinosin (P-CS), a bioactive flavonoid, is typically extracted from Semen Ziziphi Spinosae (SZS). In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to determine P-CS for investigating the degradation characteristics of P-CS incubated with rat feces. The results showed that P-CS degraded rapidly and the degradation speeds varied depending upon the P-CS concentrations (3, 15, and 30 μg/mL). The degradation of P-CS processes follow first-order kinetics. On the basis of the mass spectrometry (MS) spectrum mode of the product ions, two main metabolites of P-CS were identified. Swertisin was the main metabolite at 3 and 15 μg/mL, while spinosin was produced when the P-CS concentration was 30 μg/mL. Spinosin and swertisin could improve mRNA transcription levels of glutamate receptor K1, K2, and K3 (GluK1, GluK2, and GluK3) subunits in rat hippocampal neurons. In addition, they showed an obvious synergistic effect in this respect. Collectively, the results can be used to explain the metabolic and pharmacological mechanisms of P-CS.

Flavonoid Metabolites in Human Urine during Blueberry Anthocyanin Intake

The human health benefits of anthocyanins (Anc) and other flavonoids are widely recognized. However, the flavonoid-based urinary metabolites arising in vivo after Anc intake are not well described. Human (n = 17) urine was collected while blueberry juice (BJ) was consumed daily for 28 days and once after a 7 day washout. MS/MS scanning of 664 urine samples for 18 parent Anc (PAnc) and 42 predicted Anc metabolites (AncM) yielded 371 products (i.e., MS/MS × retention time (RT)). Flavonoid-based AncM, which were likely underestimated, were almost 20 times more abundant than PAnc. Together, PAnc and AncM accounted for about 1% of the daily Anc dose. Aglycone forms were >94% of the total. Cluster analysis of the 371 Anc identified about 55 major Anc that contributed about 80% to the total Anc. The abundance of flavonoid-based Anc-derived products in the gastrointestinal tract could contribute to the health benefits of Anc-rich berries.

Investigation of the interactions between Chrysanthemum morifolium flowers extract and intestinal bacteria from human and rat

Flos Chrysanthemi, dried flower of Chrysanthemum morifolium Ramat, has drawn much attention recently owing to its potential beneficial health effects for human. Flos Chrysanthemi products are usually taken orally and metabolized by intestinal microflora. However, there has been no investigation of the comprehensive metabolic profile of the Flos Chrysanthemi extract by intestinal flora owing to its chemical complexity and the limitations of analytical methods. In this paper, a rapid, sensitive and automated analysis method, ultra-performance liquid chromatography/quadrupole time of flight mass spectrometry including MS^E technology and automated data processing Metabolynx™ software, was developed and successfully applied for the biotransformation and metabolic profile of flavonoids in the Flos Chrysanthemi extract by intestinal flora from human and rat. A total of 32 metabolites were detected and tentatively identified in human and rat intestinal bacterial samples. These metabolites indicated that hydrolysis, hydroxylation, acetylation, methylation, hydrogenation and deoxygenation were the major conversion pathways of flavonoids in the Flos Chrysanthemi extract in vitro. Furthermore, the effects of the Flos Chrysanthemi extract on the growth of different intestinal bacteria were detected using an Emax precision microplate reader. Certain pathogenic bacteria such as Enterobacter, Enterococcus, Clostridium and Bacteroides were significantly inhibited by Flos Chrysanthemi, while commensal probiotics such as Lactobacillus and Bifidobacterium were moderately promoted. Our observation provided further evidence for the importance of intestinal bacteria in the metabolism and potential activity of the Flos Chrysanthemi extract. The results will also be helpful for the further pharmacokinetic study of Flos Chrysanthemi and to unravel how it works in vivo.