Anti-inflammatory and antiviral activities of flavone C-glycosides of Lophatherum gracile for COVID-19.

Lophatherum gracile (L. gracile) has long been used as a functional food and herbal medicine. Previous studies have demonstrated that extracts of L. gracile attenuate inflammatory response and inhibit SARS-CoV-2 replication; however, the underlying active constituents have yet to be identified. This study investigated the bioactive components of L. gracile. Flavone C-glycosides of L. gracile were found to dominate both anti-inflammatory and antiviral effects. A simple chromatography-based method was developed to obtain flavone C-glycoside-enriched extract (FlavoLG) from L. gracile. FlavoLG and its major flavone C-glycoside isoorientin were shown to restrict respiratory bursts and the formation of neutrophil extracellular traps in activated human neutrophils. FlavoLG and isoorientin were also shown to inhibit SARS-CoV-2 pseudovirus infection by interfering with the binding of the SARS-CoV-2 spike on ACE2. These results provide scientific evidence indicating the efficacy of L. gracile as a potential supplement for treating neutrophil-associated COVID-19.

Analysis on Components Absorbed into Blood of Citri Reticulatae Pericarpium in Rats Based on Sequential Metabolism and UPLC-HRMS / 中国实验方剂学杂志

ObjectiveTo study the metabolism of chemical components from Citri Reticulatae Pericarpium（CRP）in different parts of rats by sequential metabolism and ultra performance liquid chromatography-high resolution mass spectrometry（UPLC-HRMS）. MethodSD male rats were employed as experimental subjects， and blood samples of intestinal metabolism and hepatic metabolism were prepared after administration of CRP ethanol extract by in situ intestinal perfusion， and comprehensive metabolic samples were collected after intragastric administration. UPLC-HRMS was used to analyze the samples with acetonitrile（A）-0.1% formic acid aqueous solution（B）as the mobile phase for gradient elution（0-10 min， 10%-30%A； 10-30 min， 30%-95%A； 30-31 min， 95%-10%A； 31-35 min， 10%A）at a flow rate of 0.35 mL·min-1， using a heated electrospray ionization with positive and negative ion mode scanning in the range of m/z 100-1 500. Under these conditions， the differences in the profiles of CRP ethanol extract， blank plasma and drug-containing plasma under different treatment groups were compared， and the chemical components of each sample were analyzed and identified based on the retention time， accurate relative molecular mass， primary and secondary ion fragments， and the information of reference substances. ResultA total of 44 chemical components were identified in the CRP ethanol extract， including flavone-O-glycosides， flavone-C-glycosides and polymethoxyflavonoids， etc. The results of sequential metabolism showed that 22 chemical components in CRP were detected in the intestinal metabolic sample， 18 chemical components were detected in the hepatic metabolic sample， and 9 identical chemical components（narirutin， hesperidin， meranzin， 5，7，8，3ʹ，4ʹ，5ʹ-hexamethoxy-flavone， isosinensetin， sinensetin， 3，5，6，7，8，3ʹ，4ʹ-heptamethoxyflavone， nobiletin and tangeretin）could be detected in all three metabolic samples， with a total of 22 compounds entering the blood in prototype form. ConclusionThe identified 21 components with well-defined structures entering the blood as prototypes may be potential active components of CRP， and differences in the components at different metabolic parts can provide an experimental basis for elucidating the in vivo biotransformation process of the metabolic components of CRP.

Isolation and identification of Enterococcus gallinarum P581a, a strain of intestinal bacteria deglycosylating flavone C-glycosides.

Flavone C-glycosides are not easily degraded because of their strong C-C bond between sugar moieties and aglycones. However, some bacteria such as intestinal species can produce specific enzymes to degrade them. In this study, a bacterial strain P581a, which is capable of deglycosylating flavone C-glycosides, was isolated from human intestinal bacteria and was identified as Enterococcus gallinarum by morphological examination, physiological and biochemical analysis and 16S rRNA gene sequencing. This strain may produce a specific flavonoside glycosidase. The activity of the enzyme in the culture medium containing different quantity of carbon sources was also studied, and it was found that the content of carbon sources is negatively correlated with the deglycosylation efficiency of this strain.

Cytotoxic activity of standardized extracts, a fraction, and individual secondary metabolites from fenugreek seeds against SKOV-3, HeLa and MOLT-4 cell lines.

CONTEXT: Trigonella foenum-graecum L. (Fabaceae) has many therapeutic properties and anticancer potential. OBJECTIVE: The cytotoxic activities of standardized extracts and a fraction from fenugreek seeds and their compounds (sapogenins, flavone C-glycosides, alkaloid trigonelline) against human cancer SKOV-3, HeLa and MOLT-4 cells were evaluated. MATERIALS AND METHODS: Fenugreek seeds were extracted with 70% methanol (A) or water (B). Furthermore, the seeds were purified with petroleum ether and chloroform and next extracted with methanol to obtain fraction (C). The quantitative analysis of saponins and flavonoids in the extracts was done with HPLC methods. The extracts (5-120 µg/mL) and compounds (1-50 µg/mL) were tested on the cells by MTT assay and RTCA system. The effect of a fraction on ROS production, mitochondrial membrane potential and caspase-3/7 activity in HeLa and SKOV-3 cells was also evaluated by flow cytometry. RESULTS: The strongest cytotoxic activity on cancer cells showed the fraction C (IC50 was 3.91 ± 0.03 for HeLa, 3.97 ± 0.07 for SKOV-3, and 7.75 ± 0.37 for MOLT-4) with the highest content of steroidal saponins (163.18 ± 11.03 µg/mg) and flavone C-glycosides (820.18 ± 0.05 µg/mg). The fraction significantly increased ROS production (up to four times higher than in keratinocytes as control) and caspases activity in the cells. The examined flavonoids did not exhibit the cytotoxic activity in contrast to yamogenin, tigogenin, and diosgenin. CONCLUSIONS: The obtained results complement the data on the cytotoxic activity of Foenugraeci Semen and synergistic effect of flavonoids and saponins complex contained in the plant.

Analysis of Chemical Constituents in Microctis Folium by UPLC-Q-TOF-MS/MS / 中国实验方剂学杂志

Objective:To analyze the chemical constituents in Microctis Folium by ultra performance liquid chromatography-quadrupole-time-of-flight high resolution mass spectrometry （UPLC-Q-TOF-MS/MS）. Method:Waters CORTECS UPLC C₁₈ column （2.1 mm×150 mm， 1.6 μm） was used for chromatographic separation with the mobile phase of methanol （A） -0.1% formic acid solution （B） for gradient elution （0-4 min， 14%-30%A； 4-16 min， 30%-58%A； 16-25 min， 58%-78%A； 25-25.1 min， 78%-98%A； 25.1-29 min， 98%A）， the flow rate was 0.25 mL· min^-1， the injection volume was 1 μL. The electrospray ionization （ESI） was adopted for determining the chromatographic effluent under positive and negative ion modes， the main chromatographic peaks were assigned and distinguished by Q-TOF， and the scanning range was <italic>m</italic>/<italic>z</italic> 100-1 500. Result:A total of 31 chemical constituents in Microctis Folium were identified by confirmation of reference substances， literature comparison and high resolution mass spectrometry data analysis. The chemical constituent cluster was composed of 28 flavonoids （9 flavone C-glycosides， 10 flavonols and their glycosides， 8 proanthocyanidins， 1 xanthone） and 3 organic acids （caffeic acid， <italic>p</italic>-coumaric acid， ferulic acid）. Conclusion:UPLC-Q-TOF-MS/MS technique provides a simple， rapid and accurate method for the identification of chemical constituents in Microctis Folium. Flavone C-glycosides， flavonol oxyglycosides and proanthocyanidins are the main chemical constituents. The 7 proanthocyanidins are reported for the first time in this herb. In conclusion， the chemical profile of Microctis Folium is characterized and the findings are meaningful for the in-depth quality assessment and material basis clarification of Microctis Folium.

Flavonoids are indispensable for complete male fertility in rice.

Flavonoids are essential for male fertility in some but not all plant species. In rice (Oryza sativa), the chalcone synthase mutant oschs1 produces flavonoid-depleted pollen and is male sterile. The mutant pollen grains are viable with normal structure, but they display reduced germination rate and pollen-tube length. Analysis of oschs1/+ heterozygous lines shows that pollen flavonoid deposition is a paternal effect and fertility is independent of the haploid genotypes (OsCHS1 or oschs1). To understand which classes of flavonoids are involved in male fertility, we conducted detailed analysis of rice mutants for branch-point enzymes of the downstream flavonoid pathways, including flavanone 3-hydroxylase (OsF3H; flavonol pathway entry enzyme), flavone synthase II (CYP93G1; flavone pathway entry enzyme), and flavanone 2-hydroxylase (CYP93G2; flavone C-glycoside pathway entry enzyme). Rice osf3h and cyp93g1 cyp93g2 CRISPR/Cas9 mutants, and cyp93g1 and cyp93g2 T-DNA insertion mutants showed altered flavonoid profiles in anthers, but only the osf3h and cyp93g1 cyp93g2 mutants displayed reduction in seed yield. Our findings indicate that flavonoids are essential for complete male fertility in rice and a combination of different classes (flavanones, flavonols, flavones, and flavone C-glycosides) appears to be important, as opposed to the essential role played primarily by flavonols that has been previously reported in several plant species.

[Effects and active substances of ethanol extract from Dendrobium officinale on metabolic hypertensive rats induced by comprehensive dietary].

Previous studies of Dendrobium officinale on anti-hypertension effect always focused only on the blood pressure,while polysaccharides of D. officinale( DOP) have been traditionally considered as one of the main effective substances. This study aimed to evaluate the effect of ethanol extract from D. officinale( DOE) on blood pressure,Glu and lipid profile in metabolic hypertensive rats induced by comprehensive dietary factors,and elucidate the composition of effective fractions from DOE. A metabolic hypertension model of rat induced by high-sugar,high-fat diet and alcohol drinking was adopted to evaluate the effect of DOE on hypertension and other metabolic disorders. Blood pressure,Glu and lipid profile were detected to find the features and differences of DOE and DOP on metabolic hypertension. Furthermore,DOE was separated with three different common solvents according to the polarity. Along with blood pressure,Glu,UA and lipid profile,hemorheology,oxidative index and aortas structure changes were adopted to evaluate the comprehensive effects of the most effective fractions on metabolic hypertension. Finally,HPLC-DAD-MS was adopted to identify the components of the most effective fraction. The SBP and Glu of models were decreased significantly after administration of DOE and DOP for 6 weeks,while TG in DOE groups also reduced dramatically. The DOE was separated with ether,n-butanol respectively and named NAF,NBF and NCF. SBP,TG,Glu,UA of model rats were decreased significantly after 4 weeks administration with NBF. The level of MDA in serum was down-regulated,while GSH-Px and T-AOC were up-regulated obviously after 12 weeks.And the blood viscosity also obviously decreased,with less collagen deposition of aortas by Masson's trichrome staining. NBF was mainly composed of phenols and flavone C-glycosides,whose aglycone was apigenin,and monosaccharide was connected to C-6 and C-8. Ethanol extract from D.officinale has an positive effect in alleviating hypertension and metabolic disorders in metabolic hypertension. Medium polarity fraction was the effective fraction of alcohol extraction from D. officinale,and mainly composed of phenols and flavone C-glycosides.

Phytochemical Profile and Antidepressant Effect of Ormosia henryi Prain Leaf Ethanol Extract.

The Ormosia henryi Prain leaf (OHPL) is a new bioactive resource with potential antidepressant activity, but few reports have confirmed its chemical composition or antidepressant effect. To investigate the phytochemical profile of OHPL ethanol extract (OHPLE), six flavone C-glycosides and two flavone O-glycosides were purified by high-speed counter-current chromatography combined with preparative high-performance liquid chromatography (HSCCC-prep-HPLC). The eight isolated compounds were identified by NMR and MS. Forty-six flavonoids, including flavones, flavone C-glycosides, flavone O-glycosides, isoflavones, isoflavone O-glycosides, prenylflavones and polymethoxyflavones were definitively or tentatively identified from OHPLE using ultra-performance liquid chromatography/ electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS/MS) on the basis of fragment ions that are characteristic of these isolated compounds. The results of the antidepressant assay suggest that OHPLE significantly improved depression-related behaviors of chronic unpredictable mild stress (CUMS) mice. The observed changes in these mice after OHPLE treatment were an increased sucrose preference index, reduced feeding latency, prolonged tail suspension time, and upregulated expression of brain-derived neurotrophic factor (BDNF). The details of the phytochemicals and the antidepressant effect of OHPLE are reported here for the first time. This study indicates that the OHPL, enriched in flavone C-glycosides, is a new resource that might be potentially applied in the field of nutraceuticals (or functional additives) with depression-regulating functions.

A newly isolated human intestinal bacterium strain capable of deglycosylating flavone C-glycosides and its functional properties.

BACKGROUND: Flavone C-glycosides are difficult to be deglycosylated using traditional chemical methods due to their solid carbon-carbon bond between sugar moieties and aglycones; however, some bacteria may easily cleave this bond because they generate various specific enzymes. RESULTS: A bacterial strain, named W12-1, capable of deglycosylating orientin, vitexin, and isovitexin to their aglycones, was isolated from human intestinal bacteria in this study and identified as Enterococcus faecalis based on morphological examination, physiological and biochemical identification, and 16S rDNA sequencing. The strain was shown to preferentially deglycosylate the flavone C-glycosides on condition that the culture medium was short of carbon nutrition sources such as glucose and starch, and its deglycosylation efficiency was negatively correlated with the content of the latter two substances. CONCLUSION: This study provided a new bacterial resource for the cleavage of C-glycosidic bond of flavone C-glycosides and reported the carbon nutrition sources reduction induced deglycosylation for the first time.

Preparation of flavone di-C-glycoside isomers from Jian-Gu injection (Premna fulva Craib.) using recycling counter-current chromatography.

Jian-Gu Injection (JGI, Premna fulva Craib) has been demonstrated to be effective in the clinical treatment of bone hyperplasia. However, an effective purification method of the JGI flavone C-glycosides as reference materials is not available. The present work developed a recycling counter-current chromatography approach to prepare these materials in high quality. An optimized biphasic solvent system composed of ethyl acetate/n-butanol/water (1:9:10, v/v/v) was employed to purify the five congeneric flavone C-glycosides, identified as apigenin 6,8-di-C-ß-d-glucopyranoside (vicenin 2), apigenin 6-C-ß-d-xylopyranosyl-8-C-ß-d-glucopyranoside (vicenin 1), apigenin 6-C-ß-d-xylopyranosyl-8-C-ß-d-galactopyranoside, apigenin 6-C-ß-d-glucopyranosyl-8-C-ß-d-xylopyranoside (vicenin 3), and apigenin 6-C-ß-d-galactopyranosyl-8-C-ß-d-xylopyranoside, by means of UHPLC-PDA-ESI-IT-ToF-MSn and NMR spectroscopy.

Recruitment of specific flavonoid B-ring hydroxylases for two independent biosynthesis pathways of flavone-derived metabolites in grasses.

In rice (Oryza sativa), OsF2H and OsFNSII direct flavanones to independent pathways that form soluble flavone C-glycosides and tricin-type metabolites (both soluble and lignin-bound), respectively. Production of soluble tricin metabolites requires CYP75B4 as a chrysoeriol 5'-hydroxylase. Meanwhile, the close homologue CYP75B3 is a canonical flavonoid 3'-hydroxylase (F3'H). However, their precise roles in the biosynthesis of soluble flavone C-glycosides and tricin-lignins in cell walls remain unknown. We examined CYP75B3 and CYP75B4 expression in vegetative tissues, analyzed extractable flavonoid profiles, cell wall structure and digestibility of their mutants, and investigated catalytic activities of CYP75B4 orthologues in grasses. CYP75B3 and CYP75B4 showed co-expression patterns with OsF2H and OsFNSII, respectively. CYP75B3 is the sole F3'H in flavone C-glycosides biosynthesis, whereas CYP75B4 alone provides sufficient 3',5'-hydroxylation for tricin-lignin deposition. CYP75B4 mutation results in production of apigenin-incorporated lignin and enhancement of cell wall digestibility. Moreover, tricin pathway-specific 3',5'-hydroxylation activities are conserved in sorghum CYP75B97 and switchgrass CYP75B11. CYP75B3 and CYP75B4 represent two different pathway-specific enzymes recruited together with OsF2H and OsFNSII, respectively. Interestingly, the OsF2H-CYP75B3 and OsFNSII-CYP75B4 pairs appear to be conserved in grasses. Finally, manipulation of tricin biosynthesis through CYP75B4 orthologues can be a promising strategy to improve digestibility of grass biomass for biofuel and biomaterial production.

Effects and active substances of ethanol extract from Dendrobium officinale on metabolic hypertensive rats induced by comprehensive dietary / 中国中药杂志

Previous studies of Dendrobium officinale on anti-hypertension effect always focused only on the blood pressure,while polysaccharides of D. officinale( DOP) have been traditionally considered as one of the main effective substances. This study aimed to evaluate the effect of ethanol extract from D. officinale( DOE) on blood pressure,Glu and lipid profile in metabolic hypertensive rats induced by comprehensive dietary factors,and elucidate the composition of effective fractions from DOE. A metabolic hypertension model of rat induced by high-sugar,high-fat diet and alcohol drinking was adopted to evaluate the effect of DOE on hypertension and other metabolic disorders. Blood pressure,Glu and lipid profile were detected to find the features and differences of DOE and DOP on metabolic hypertension. Furthermore,DOE was separated with three different common solvents according to the polarity. Along with blood pressure,Glu,UA and lipid profile,hemorheology,oxidative index and aortas structure changes were adopted to evaluate the comprehensive effects of the most effective fractions on metabolic hypertension. Finally,HPLC-DAD-MS was adopted to identify the components of the most effective fraction. The SBP and Glu of models were decreased significantly after administration of DOE and DOP for 6 weeks,while TG in DOE groups also reduced dramatically. The DOE was separated with ether,n-butanol respectively and named NAF,NBF and NCF. SBP,TG,Glu,UA of model rats were decreased significantly after 4 weeks administration with NBF. The level of MDA in serum was down-regulated,while GSH-Px and T-AOC were up-regulated obviously after 12 weeks.And the blood viscosity also obviously decreased,with less collagen deposition of aortas by Masson's trichrome staining. NBF was mainly composed of phenols and flavone C-glycosides,whose aglycone was apigenin,and monosaccharide was connected to C-6 and C-8. Ethanol extract from D.officinale has an positive effect in alleviating hypertension and metabolic disorders in metabolic hypertension. Medium polarity fraction was the effective fraction of alcohol extraction from D. officinale,and mainly composed of phenols and flavone C-glycosides.

Two flavone C-glycosides as quality control markers for the manufacturing process of ephedrine alkaloids-free Ephedra Herb extract (EFE) as a crude drug preparation.

As part of our continuing study of ephedrine alkaloids-free Ephedra Herb extract (EFE) in pursuit of its approval as a crude drug preparation, we identified two quantitative markers for the quality control of the manufacturing process of EFE and sought to establish cost-effective and simple methods for quantitative analyses. We analysed Ephedra Herb extracts grown in different habitats and collection years by liquid chromatography/high-resolution mass spectrometry (LC/HRMS) and detected two notable peaks common to each extract. These peaks were identified as vicenin-2 (1) and isovitexin 2″-O-rhamnoside (2). Quantitative analyses using the isocratic condition of LC/MS showed that the content percentages of 1 and 2 in EFE were 0.140-0.146% and 0.350-0.411%, respectively. We concluded that 1 and 2 were adequate quality control markers for quantitative analysis of EFE. Furthermore, we quantitatively analysed apigenin (3), an aglycon common to 1 and 2, and found that the conversion factors of 1 to 3 and 2 to 3 were 1.3 and 1.5, respectively. Therefore, we concluded that 3 was a secondary standard for quantifying the contents of 1 and 2 in EFE. A series of results obtained from this study will be valuable for the quality control of EFE.

Cloning, bioinformatics, and expression analysis of MpF2H gene in Microcos paniculata / 中草药

Objective To obtain the key enzyme gene involved in flavone C-glycosides biosynthesis pathway, a flavanone 2-hydroxylase (F2H) gene was cloned from Microcos paniculata, and its bioinformatics analysis and gene expression pattern were also performed. Methods The specific primers were designed according to Unigene in F2H annotated in the transcriptome data of M. paniculata. The open reading frame (ORF) of MpF2H gene was amplified by PCR. Then the PCR product was purified and ligated to pET30a, and finally a prokaryotic expression vector pET30a-MpF2H was constructed. The bioinformation of F2H gene cDNA sequences was analyzed by some online tools. Using RT-qPCR with suitable primers, the quantitative expression analysis of MpF2H gene in different tissues, namely, buds, leaves, twigs, flowers and fruits was carried out. Results The length of MpF2H gene ORF was 1 557 bp (GenBank accession number KY652921), which encoded a protein with 518 amino acid residues, relative molecular weight of 54 500, theory isoelectric point of 5.49. In which was no transmembrane domain. It was hypothesized that this protein located in chloroplast. MpF2H gene was expressed in different tissues, with the highest expression in leaves and the lowest expression in twigs and flowers. Conclusion The expression of MpF2H gene varied widely in different tissues. The MpF2H gene was cloned from M. paniculata based on pET30a-MpF2H expression vector. This study will provide the fundamental information for the further preparation and functional research of MpF2H protein in flavone C-glycosides biosynthesis pathway.

Molecular targets of vitexin and isovitexin in cancer therapy: a critical review.

Cancer is a primary public health problem and the second leading cause of death worldwide. It causes life-threatening malignancies and results in high financial costs for both patients and the healthcare system. Hence, it is important to develop effective long-term strategies pertaining to prevention and control of cancers. Plant-derived secondary metabolites have been shown to have positive roles against various cancers. A number of plant extracts have been evaluated for possible use in the treatment of cancer; some have provided direction for new strategies for the research and development of antitumor agents. Here, we provide comprehensive data on various cancers, potential molecular mechanisms, and therapeutic implications of just two plant-derived compounds, vitexin and isovitexin. Information on the chemotherapeutic potential of vitexin and isovitexin was collected from a library database and through electronic searches (ScienceDirect, Pubmed, and Google Scholar). Both in vitro and in vivo studies suggest that vitexin and isovitexin are chemopreventive compounds with activity against various cancers through proapoptotic processes and/or autophagy.

Antiplasmodial, anti-complement and anti-inflammatory in vitro effects of Biophytum umbraculum Welw. traditionally used against cerebral malaria in Mali.

ETHNOPHARMACOLOGICAL RELEVANCE: Biophytum umbraculum Welw. (Oxalidaceae) is a highly valued African medicinal plant used for treatment of cerebral malaria, a critical complication of falciparum malaria. AIM OF THE STUDY: To provide additional information about traditional use of B. umbraculum and to test plant extracts and isolated compounds for in vitro activities related to cerebral malaria. MATERIALS AND METHODS: The traditional practitioners were questioned about indication, mode of processing/application, dosage and local name of B. umbraculum. Organic extracts and some main constituents of the plant were investigated for anti-malaria, anti-complement activity and inhibition of NO secretion in a RAW 264.7 cell line. RESULTS: Treatment of cerebral malaria was the main use of B. umbraculum (fidelity level 56%). The ethyl acetate extract showed anti-complement activity (ICH50 5.7±1.6µg/ml), inhibition of macrophage activation (IC50 16.4±1.3µg/ml) and in vitro antiplasmodial activity (IC50 K1 5.6±0.13µg/ml, IC50 NF54 6.7±0.03µg/ml). The main constituents (flavone C-glycosides) did not contribute to the activity of the extract. CONCLUSION: Inhibition of complement activation and anti-inflammatory activity of B. umbraculum observed in this study might be possible targets for adjunctive therapy in cerebral malaria together with its antiplasmodial activity. However, clinical trials are necessary to evaluate the activity due to the complex pathogenesis of cerebral malaria.

Indoleacetic acid derivatives from the seeds of Ziziphus jujuba var. spinosa.

A pair of diastereoisomers, the N-glycosylated derivatives of dioxindole-3-hydroxy-3-acetic acid 1-2, and their conjugates with flavonoids 3-8, was isolated from the seeds of Ziziphus jujuba var. spinosa. Their structures were elucidated by NMR spectroscopic analyses, and the absolute configurations were determined by circular dichroism method. Compounds 3-10 were evaluated for the antioxidant capacity, using the radical absorbance capacity (ORAC) assay.

Cytoprotective and antioxidant effects of phenolic compounds from Haberlea rhodopensis Friv. (Gesneriaceae).

BACKGROUND: Haberlea rhodopensis Friv. (Gesneriaceae) is a rare poikilohydric endemic and preglacial relict growing in Balkan Peninsula. Previous investigations demonstrated strong antioxidant, antimicrobial and antimutagenic potential of alcoholic extract from the plant. OBJECTIVE: The isolation of known caffeoyl phenylethanoid glucoside - myconoside and flavone-C-glycosides hispidulin 8-C-(2-O-syringoyl-ß-glucopyranoside), hispidulin 8-C-(6-O-acetyl-2-O-syringoyl-ß-glucopyranoside), and hispidulin 8-C-(6-O-acetyl-ß-glucopyranoside) from the leaves of H. rhodopensis was carried out. The aim of this study was to investigate cyto-protective and antioxidant effects of isolated compounds. MATERIALS AND METHODS: Antioxidant activity of isolated substances was examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals; ferric reducing antioxidant power (FRAP) assay and inhibition of lipid peroxidation (LPO) in linoleic acid system by ferric thyocianate method. The compounds were investigated for their possible protective and antioxidant effects against tert-butyl hydroperoxide-induced oxidative stress in isolated rat hepatocytes. The levels of thiobarbituric acid reactive substances were assayed as an index of LPO. Lactate dehydrogenase leakage, cell viability, and reduced glutathione depletion were used as signs of cytotoxicity. RESULTS: Myconoside demonstrated the highest DPPH radical scavenging, ABTS, FRAP, and antioxidant activity in linoleic acid system as well as the highest and statistically most significant protection and antioxidant activity against the toxic agent. CONCLUSION: Phenolic compounds isolated from H. rhodopensis demonstrated significant cytoprotective, radical scavenging potential, and inhibit lipid peroxidation, moreover, myconoside was found to be a new powerful natural antioxidant.

Study on HPLC fingerprints of flavone C-glycosides in Dendrobium officinale leaves and determination of index component / 中国药学杂志

OBJECTIVE: To establish the HPLC fingerprints of flavone C-glycosides in Dendrobium officinale leaves and determine the content of apigenin-6-C-α-L-arabinoside-8-C-β-D-xyloside for the quality control. METHODS: The compounds were separated by using XB C18(4.6 mm × 250 mm, 5 μm) analytical column. The mobile phase consisted of methanol and water containing 0.4% formic acid. Gradient elution program was used. The detection wavelength was 335 nm. In total 14 batches of Dendrobium officinale leaves and 3 batches of different species from Dendrobium were analyzed. Similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (2004AB) and principal component analysis(PCA) were used in data analysis. RESULTS: The HPLC fingerprint of flavone C-glycosides of Dendrobium officinale leaves was established. In total 9 peaks were selected as the characteristic common peaks and 8 of them were identified. There were significant differences in the fingerprint chromatograms between Dendrobium officinale leaves and different species from Dendrobium. Principal component analysis showed that apigenin-6-C-α-L-arabinoside-8-C-β-D-xyloside among the flavone di-C-glycosides was the most important component. CONCLUSION The HPLC fingerprint and content of major component can be applied for identification and quality control of Dendrobium officinale leaves.

Study on eight flavone C-glycosides in dendrobium officinale leaves and their fragmentation pattern by HPLC-DAD-ESI-MSn / 中国药学杂志

OBJECTIVE: To identify flavone C-glycosides in Dendrobium officinale leaves by high performance liquid chromatography with DAD and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MSn). METHODS: The chromatographic separation was carried out at 30°C on a XB C18 column (4.6 mm × 250 mm, 5 μm) eluted with gradient program. The mobile phase consisted of methanol and water containing 0.4% formic acid. The detection wavelength was 335 nm and the on-line UV spectra was recorded in the range of 190-400 nm. The mass spectra was obtained by Agilent ion trap mass spectrometer in the negative ion mode with capillary voltage 4 500 V, dry gas temperature 350°C, dry gas flow 12.0 L · min-1, nebulizer pressure 241 kPa; mass range recorded m/z 50-600. RESULTS: Eight flavone di-C-glycosides from D. officinale leaves, whose aglycone was apigenin and monosaccharide was connected with C-6 and C-8, were identified by HPLC-DAD-ESI-MSn for the first time. The study further proved the characteristics of fragmentation pattern of flavone C-glycosides in ESI-MSn. CONCLUSION: The method is simple and rapid for the identification of D. officinale leaves. The characteristics of fragmentation pattern of ESI-MSn in flavone di-C-glycosides provide a reference for rapid detection and identification of flavone C-glycosides.