Antioxidant,Antibacterial and Dyeing Potential of Crude Pigment Extract of Gonatophragmium triuniae and Its Chemical Characterization

Filamentous fungi synthesize natural products as an ecological function. In this study, an interesting indigenous fungus producing orange pigment exogenously was investigated in detail as it possesses additional attributes along with colouring properties. An interesting fungus was isolated from a dicot plant, Maytenus rothiana. After a detailed study, the fungal isolate turned out to be a species of Gonatophragmium belonging to the family Acrospermaceae. Based on the morphological, cultural, and sequence-based phylogenetic analysis, the identity of this fungus was confirmed as Gonatophragmium triuniae. Although this fungus grows moderately, it produces good amounts of pigment on an agar medium. The fermented crude extract isolated from G. triuniae has shown antioxidant activity with an IC₅₀ value of 0.99 mg/mL and antibacterial activity against Gram-positive bacteria (with MIC of 3.91 μg/mL against Bacillus subtilis, and 15.6 μg/mL and 31.25 μg/mL for Staphylococcus aureus and Micrococcus luteus, respectively). Dyeing of cotton fabric mordanted with FeSO₄ using crude pigment was found to be satisfactory based on visual observation, suggesting its possible use in the textile industry. The orange pigment was purified from the crude extract by preparative HP-TLC. In addition, UV-Vis, FTIR, HRMS and NMR (¹H NMR, ¹³C NMR), COSY, and DEPT analyses revealed the orange pigment to be “1,2-dimethoxy-3H-phenoxazin-3-one” (C₁₄H₁₁NO₄, m/z 257). To our understanding, the present study is the first comprehensive report on Gonatophragmium triuniae as a potential pigment producer, reporting “1,2-dimethoxy-3H-phenoxazin-3-one” as the main pigment from the crude hexane extract. Moreover, this is the first study reporting antioxidant, antibacterial, and dyeing potential of crude extract of G. triuniae, suggesting possible potential applications of pigments and other bioactive secondary metabolites of the G. triuniae in textile and pharmaceutical industry.     

Towards the Optimization of Microwave-Assisted Extraction and the Assessment of Chemical Profile,Antioxidant and Antimicrobial Activity of Wine Lees Extracts

Wine lees, a sub-exploited byproduct of vinification, is considered a rich source of bioactive compounds, such as (poly)phenols, anthocyanins and tannins. Thus, the effective and rapid recovery of these biomolecules and the assessment of the bioactive properties of wine lees extracts is of utmost importance. Towards this direction, microwave-assisted extraction (MAE) factors (i.e., extraction time, microwave power and solvent/material ratio) were optimized using experimental design models in order to maximize the (poly)phenolic yield of the extracts. After optimizing the MAE process, the total phenolic content (TPC) as well as the antiradical, antioxidant and antimicrobial activity of the extracts were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed to investigate the chemical profile of wine lees extracts. Red varieties exhibited higher biological activity than white varieties. The geographical origin and fermentation stage were also considered as critical factors. The white variety Moschofilero presented the highest antioxidant, antiradical and antimicrobial activity, while Merlot and Agiorgitiko samples showed noteworthy activities among red varieties. Moreover, IR spectra confirmed the presence of sugars, amino acids, organic acids and aromatic compounds. Thus, an efficient, rapid and eco-friendly process was proposed for further valorization of wine lees extracts.     

The Profile of Polyphenolic Compounds,Contents of Total Phenolics and Flavonoids,and Antioxidant and Antimicrobial Properties of Bee Products

This study aimed to characterize bee products (bee bread, bee pollen, beeswax, and multiflorous honey) with the profile of phenolic compounds, total phenolic (TPC) and flavonoid (TFC) contents, and antioxidant and microbiological properties. The TP and TF contents could be ordered as follows: bee pollen > bee bread > beeswax > honey. The UPLC−PDA−MS/MS analysis allowed identifying 20 polyphenols. Sinapic acid dominated in bee pollen, gallic acid in the bee bread and honey, while pinobanksin was the major compound of beeswax. The data showed that bee pollen and bee bread had a stronger antioxidant potential than honey and beeswax. Moreover, the antibacterial activity of the bee products was studied using 14 bacterial strains. Bee bread’s and bee pollen’s antimicrobial activity was higher towards Gram-negative strains. In comparison, honey was more potent in inhibiting Gram-positive bacteria. Our study indicates that bee products may represent valuable sources of bioactive compounds offering functional properties.     

Characterization of Citrus nobilis Peel Methanolic Extract for Antioxidant,Antimicrobial, and Anti-Inflammatory Activity

Currently, the potential utilization of fruits and vegetable waste as a source of micronutrients and antioxidants has increased. The present study, therefore, aimed to determine the antimicrobial and anti-inflammatory activities of Citrus nobilis peel extract. A modified solvent evaporation technique was employed for peel extract preparation. For effective utilization of the natural product, quantitative analysis of phenolic compounds was carried out using liquid chromatography and mass spectroscopy technique. Phenolic and flavonoids were present in high amounts, while β-carotene and lycopene were present in vestigial amounts. The antimicrobial efficiency of peel extract was evaluated against four bacterial strains including Staphylococcus aureus (MTCC 3160), Klebsiella pneumoniae (MTCC 3384), Pseudomonas aeruginosa (MTCC 2295), and Salmonella typhimurium (MTCC 1254), and one fungal strain Candida albicans (MTCC 183), and zone of inhibition was comparable to the positive control streptomycin and amphotericin B, respectively. The extract of Citrus nobilis peels showed effective anti-inflammatory activity during human red blood cell membrane stabilization (HRBC) and albumin denaturation assay. The extracts also exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity ranging from 53.46 to 81.13%. Therefore, the obtained results suggest that Citrus nobilis peel could be used as an excellent source of polyphenols and transformed into value-added products.     

超临界流体色谱法测定银杏叶提取物中的黄酮类化合物

采用超临界流体色谱法分离测定了银杏叶提取物水解后的三个甙元－－槲皮素、山奈酚、异鼠李素的含量。以苯基柱为固定相,二氧化碳－乙醇－磷酸９０：９．９８：０．０２Ｖ／Ｖ）为流动相,三个黄酮甙元获得良好的分离,利用各甙元的转换因子计算了黄酮化合物的总黄酮的含量,这种方法定量结果准确,重现性好。     

竹叶黄酮提取工艺及体外抗氧化性研究综合实验

设计一个将中药有效成分提取、含量测定、抗氧化性能研究等集于一体,针对中药特色专业开设的综合实验。该实验以毛竹竹叶为原料,对竹叶总黄酮提取工艺参数进行考察。最佳工艺参数为：乙醇浓度为70%,料液比为1∶25,提取时间为2.0 h,提取温度为80℃时,总黄酮提取率可达2.24 mg/g,并进一步研究了竹叶黄酮的抗氧化性能。本实验涉及无机化学、有机化学中的提取理论知识,分析化学中数据处理方法及仪器分析中紫外分光光度计的使用。在锻炼了学生动手操作能力的基础上,又提高了学生对实验结果进行分析、评价的综合能力。     

Pouteria lucuma Pulp and Skin: In Depth Chemical Profile and Evaluation of Antioxidant Activity

Pouteria lucuma Ruiz and Pav., known as the ‘Gold of the Incas’ or ‘lucuma’, is a subtropical fruit belonging to the Sapotaceae family, with a very sweet flavor, used to prepare cakes, ice creams as well as in the baking and dairy industries. To date, the content of primary metabolites is known, but little information is reported about the composition in specialized metabolites. Moreover, no study is reported on skin which represent an important agricultural waste due to the high demand for lucuma. In order to have a preliminary metabolite profile of Pouteria lucuma, the extracts of pulp and skin have been analyzed by LC-ESI/LTQOrbitrap/MS/MS in negative ion mode. The careful analysis of the accurate masses, of the molecular formulas and of the ESI/MS spectra allowed to identify specialized metabolites belonging to phenolic, flavonoid and polar lipid classes. The LC-MS/MS analysis guided the isolation of compounds occurring in the pulp extract whose structures have been characterized by spectroscopic methods including 1D- and 2D-NMR experiments and ESI-MS analysis. Furthermore, the phenolic content of the extracts along with the antioxidant activity of extracts and isolated compounds was evaluated.     

Investigation and Biological Assessment of Rumex vesicarius L. Extract: Characterization of the Chemical Components and Antioxidant,Antimicrobial, Cytotoxic,and Anti-Dengue Vector Activity

The objective of this study was to assess the biological potency and chemical composition of Rumex vesicarius aboveground parts using GC–MS. In this approach, 44 components were investigated, comprising 99.99% of the total volatile compounds. The major components were classified as fatty acids and lipids (51.36%), oxygenated hydrocarbons (33.59%), amines (7.35%), carbohydrates (6.06%), steroids (1.21%), and alkaloids (0.42%). The major components were interpreted as 1,3-dihydroxypropan-2-yl oleate (oxygenated hydrocarbons, 18.96%), ethyl 2-hydroxycyclohexane-1-carboxylate (ester of fatty acid, 17.56%), and 2-propyltetrahydro-2H-pyran-3-ol (oxygenated hydrocarbons, 11.18%). The DPPH antioxidant activity of the extracted components of R. vesicarius verified that the shoot extract was the most potent with IC₅₀ = 28.89 mg/L, with the percentages of radical scavenging activity at 74.28% ± 3.51%. The extracted plant, on the other hand, showed substantial antibacterial activity against the diverse bacterial species, namely, Salmonella typhi (23.46 ± 1.69), Bacillus cereus (22.91 ± 0.96), E. coli (21.07 ± 0.80), and Staphylococcus aureus (17.83 ± 0.67). In addition, the extracted plant was in vitro assessed as a considerable anticancer agent on HepG2 cells, in which MTT, cell proliferation cycle, and DNA fragmentation assessments were applied on culture and treated cells. The larvicidal efficacy of the extracted plant was also evaluated against Aedes aegypti, the dengue disease vector. As a result, we may infer that R. vesicarius extract increased cytocompatibility and cell migratory capabilities, and that it may be effective in mosquito control without causing harm.     

In Vitro Human Skin Penetration,Antioxidant and Antimicrobial Activity of Ethanol-Water Extract of Fireweed (Epilobium angustifolium L.)

Epilobium angustifolium L. is applied as an antiseptic agent in the treatment of skin diseases. However, there is a lack of information on human skin penetration of active ingredients with antioxidative potential. It seems crucial because bacterial infections of skin and subcutaneous tissue are common and partly depend on oxidative stress. Therefore, we evaluated in vitro human skin penetration of fireweed ethanol-water extracts (FEEs) by determining antioxidant activity of these extracts before and after penetration study using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and Folin–Ciocalteu methods. Microbiological tests of extracts were done. The qualitative and quantitative evaluation was performed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC-UV) methods. The in vitro human skin penetration using the Franz diffusion chamber was assessed. The high antioxidant activity of FEEs was found. Gallic acid (GA), chlorogenic acid (ChA), 3,4-dihydroxybenzoic acid (3,4-DHB), 4-hydroxybenzoic acid (4-HB), and caffeic acid (CA) were identified in the extracts. The antibacterial activities were found against Serratia lutea, S. marcescens, Bacillus subtilis, B. pseudomycoides, and B. thuringiensis and next Enterococcus faecalis, E. faecium, Streptococcus pneumoniae, Pseudomonas aeruginosa, and P. fluorescens strains. In vitro penetration studies showed the penetration of some phenolic acids and their accumulation in the skin. Our results confirm the importance of skin penetration studies to guarantee the efficacy of formulations containing E. angustifolium extracts.     

High-Resolution Mass Spectrometry Identification and Characterization of Flavonoids from Fridericia chica Leaves Extract with Anti-Arbovirus Activity

Plant extracts are complex mixtures that are difficult to characterize, and mass spectrometry is one of the main techniques currently used in dereplication processes. Fridericia chica is a species with medicinal uses in Latin American countries, used in the treatment of inflammatory and infectious diseases. Extracts of this plant species are characterized by the presence of anthocyanidins. In this study, using high-resolution mass spectrometry coupled with liquid chromatography, it was possible to determine the molecular formula of thirty-nine flavonoids. Fragmentation analysis, ultraviolet spectrum and nuclear magnetic resonance data allowed the partial characterization of the structures of these compounds. The spectral dataset allowed the identification of a series of flavones in addition to the desoxyanthocyanidins common in extracts of the species. The occurrence of some of the proposed structures is uncommon in extracts of species of the Bignoniaceae family, and they are reported for the first time in the extract of this species. Quantitative analyses of total flavonoids confirmed the high content of these constituents in the species, with 4.09 ± 0.34 mg/g of dry plant material. The extract under study showed low in vitro cytotoxicity with CC₅₀ ≥ 296.7 ± 1.4 µg/mL for Vero, LLC-MK2 and MRC-5 cell lines. In antiviral activity assays, inhibition of the cytopathic effects of Dengue, Zika and Mayaro viruses was observed, with EC₅₀ values ranging between 30.1 and 40.9 µg/mL. The best result was observed against the Mayaro virus, with an EC₅₀ of 30.1 µg/mL.     

Antibiofilm and Anti-Quorum Sensing Potential of Cycloartane-Type Triterpene Acids from Cameroonian Grassland Propolis: Phenolic Profile and Antioxidant Activity of Crude Extract

Propolis is very popular for its beneficial health properties, such as antimicrobial activity and antioxidant effects. It is one of the most long-serving traditional medicines to mankind due to its interesting chemical diversity and therapeutic properties. The detailed chemical information of propolis samples is very necessary to guarantee its safety and for it to be accepted into health care systems. The phenolic profile of the hydroethanolic extract was determined using HPLC-DAD, and the antioxidant was evaluated using five complementary methods. Triterpenoids were isolated using column chromatography and characterized using ¹H NMR and ¹³C NMR. The effects of the extract and the isolated compounds on quorum sensing mediated processes and biofilm formation in bacteria were evaluated. Protocatechic acid (40.76 ± 0.82 µg/g), 4-hydroxybenzoic acid (24.04 ± 0.21 µg/g), vanillic acid (29.90 ± 1.05 µg/g), quercetin (43.53 ± 1.10 µg/g), and luteolin (4.44 ± 0.48 µg/g) were identified and quantified. The extract showed good antioxidant activity in the DPPH^•, ABTS^•+, CUPRAC, and metal chelating assays, and this antioxidant effect was confirmed by cyclic voltammetry. 27-Hydroxymangiferonic acid (1), Ambolic acid (2), and Mangiferonic acid (3) were isolated from anti-quorum sensing activity at MIC, and it was indicated that the most active sample was the extract with inhibition diameter zone of 18.0 ± 1.0 mm, while compounds 1, 2, and 3 had inhibition zones of 12.0 ± 0.5 mm, 9.0 ± 1.0 mm, and 12.3 ± 1.0 mm, respectively. The samples inhibited the P. aeruginosa PA01 swarming motility at the three tested concentrations (50, 75, and 100 μg/mL) in a dose-dependent manner. The propolis extract was able to inhibit biofilm formation by S. aureus, E. coli, P. aeruginosa, C. albicans, and C. tropicalis at MIC concentration. Compound 1 proved biofilm inhibition on S. aureus, L. monocytogenes, E. faecalis, E. coli, and C. tropicalis at MIC and MIC/2; compound 2 inhibited the formation of biofilm at MIC on S. aureus, E. faecalis, E. coli, S. typhi, C. albicans, and C. tropicalis; and compound 3 inhibited biofilm formation on E. faecalis, E. coli, C. albicans, and C. tropicalis and further biofilm inhibition on E. coli at MIC/4 and MIC/8. The studied propolis sample showed important amounts of cycloartane-type triterpene acids, and this indicates that there can be significant intra-regional variation probably due to specific flora within the vicinity. The results indicate that propolis and its compounds can reduce virulence factors of pathogenic bacteria.     

Antioxidant and Anti-Inflammatory Activity of Filipendula glaberrima Nakai Ethanolic Extract and Its Chemical Composition

Many countries are endeavoring to strengthen the competitiveness of their biological resources by exploring and developing wild endemic plants. This study examined the effects of Filipendula glaberrima Nakai (FG) on the antioxidant and anti-inflammatory activity using an in vitro system. The bioactive components were also examined using chromatographic techniques. The ethanol extract of Filipendula glaberrima Nakai (FGE) exerted antioxidant activities in the radical scavenging and reducing power assays and had high amounts of total polyphenolic compounds. The qRT-PCR results suggested that FGE significantly downregulated the levels cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) 2, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in LPS-stimulated RAW 264.7 cells. The FGE treatment also decreased the production of nitric oxide, TNF-α, and IL-6 significantly in a dose-dependent manner. In addition, FGE downregulated phosphorylation of MAPK and NF-κB signaling pathway-related proteins. The chromatographic and mass spectrometry results showed that FGE contained bioactive flavonoids such as (+)-catechin, miquelianin, quercitrin, and afzelin, which may be active compounds with antioxidant and anti-inflammatory activities. This study provides fundamental data on the anti-inflammatory activity of the FG and can serve as a good starting point for developing a novel natural anti-inflammatory agent using FGE-containing bioactive flavonoids.     

Phytochemical Composition,Antioxidant Activity, α-Glucosidase and Acetylcholinesterase Inhibitory Activity of Quinoa Extract and Its Fractions

This study is aimed to evaluate the chemical compositions and biological activities of quinoa, a novel and excellent food crop. Quinoa extract and its fractions were prepared by ethanol extraction and liquid-liquid extraction, including ethanol crude extract, and petroleum ether, chloroform, ethyl acetate (EAF), and n-butanol and water fractions. The total phenolic and flavonoid contents, antioxidant activities, α-glucosidase and acetylcholinesterase inhibitory abilities of the extract and fractions were further determined. Based on these foundations, the chemical composition of the EAF fraction exhibiting the strongest functional activity was analyzed by ultra-performance liquid chromatography-mass spectrometry. The results showed the EAF fraction had the highest phenolic and flavonoid contents, and the highest antioxidant activities, as well as the strongest α-glucosidase and acetylcholinesterase inhibitory abilities, which is even better than the positive control. The phytochemical composition of the EAF fraction indicated that 661 and 243 metabolites were identified in positive and negative ion modes, which were classified into superclass, class and subclass levels, respectively. Phenolic acids and flavonoids were the major bioactive compounds in the EAF fraction. This study found that quinoa, especially its ethyl acetate fraction, had the potential for the development of natural antioxidants, acetylcholinesterase inhibitors, and hypoglycemic agents.     

Antioxidant and Antiproliferative Activity of the Ethanolic Extract of Equisetum myriochaetum and Molecular Docking of Its Main Metabolites (Apigenin,Kaempferol, and Quercetin) on β-Tubulin

Equisetum myriochaetum is a semi-aquatic plant found on riverbanks that is commonly used in traditional medicine as a diuretic agent. Additionally, the genus Equisetum stands out for its content of the flavonoid kaempferol, a well-known antiproliferative agent. Therefore, in this study, E. myriochaetum ethanolic extract was tested in vitro against a cervical cancer cell line (SiHa). Additionally, the antioxidative activity was evaluated through a 2,2-diphenyl-1-picrilhidrazil (DPPH) assay. Finally, a molecular docking analysis of apigenin, kaempferol, and quercetin on the active site of β-tubulin was performed to investigate their potential mechanism of action. All fractions of E. myriochaetum ethanolic extract showed antioxidative activity. Fraction 14 displayed an antiproliferative capacity with a half maximal inhibitory concentration (IC₅₀) value of 6.78 μg/mL against SiHa cells.     

GC/MS Analysis,Antioxidant Activity,and Antimicrobial Effect of Pelargonium peltatum (Geraniaceae)

In recent years, the increase in antibiotic resistance demands searching for new compounds with antimicrobial activity. Phytochemicals found in plants offer an alternative to this problem. The genus Pelargonium contains several species; some have commercial use in traditional medicine such as P. sinoides, and others such as P. peltatum are little studied but have promising potential for various applications such as phytopharmaceuticals. In this work, we characterized the freeze-dried extracts (FDEs) of five tissues (root, stem, leaf, and two types of flowers) and the ethyl acetate fractions from leaf (Lf-EtOAc) and flower (Fwr-EtOAc) of P. peltatum through the analysis by thin-layer chromatography (T.L.C.), gas chromatography coupled to mass spectrometry (GC-MS), phytochemicals quantification, antioxidant capacity, and antimicrobial activity. After the first round of analysis, it was observed that the FDE-Leaf and FDE-Flower showed higher antioxidant and antimicrobial activities compared to the other FDEs, for which FDE-Leaf and FDE-Flower were fractionated and analyzed in a second round. The antioxidant activity determined by ABTS showed that Lf-EtOAc and Fwr-EtOAc had the lowest IC₅₀ values with 27.15 ± 1.04 and 28.11 ± 1.3 µg/mL, respectively. The content of total polyphenols was 264.57 ± 7.73 for Lf-EtOAc and 105.39 ± 4.04 mg G.A./g FDE for Fwr-EtOAc. Regarding the content of flavonoid, Lf-EtOAc and Fw-EtOAc had the highest concentration with 34.4 ± 1.06 and 29.45 ± 1.09 mg Q.E./g FDE. In addition, the minimum inhibitory concentration (M.I.C.) of antimicrobial activity was evaluated: Lf-EtOAc and Fwr-EtOAc were effective at 31.2 µg/mL for Staphylococcus aureus and 62.5 µg/mL for Salmonella enterica, while for the Enterococcus feacalis strain, Fwr-EtOAc presented 31.2 µg/mL of M.I.C. According to the GC-MS analysis, the main compounds were 1,2,3-Benzenetriol (Pyrogallol), with 77.38% of relative abundance in the Lf-EtOAc and 71.24% in the Fwr-EtOAc, followed by ethyl gallate (13.10%) in the Fwr-EtOAc and (Z)-9-Octadecenamide (13.63% and 6.75%) in both Lf-EtOAc and Fwr-EtOAc, respectively.     

Chemical Profile,Antioxidant Properties and Antimicrobial Activities of Malaysian Heterotrigona itama Bee Bread

The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC₅₀ 1.914 µg/mL), followed by E. coli (MIC₅₀ 1.923 µg/mL), Shigella (MIC₅₀ 1.813 µg/mL) and Salmonella typhi (MIC₅₀ 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases.     

Identification of Iridoids,Flavonoids and Triterpenes from the Methanolic Extract of Melampyrum bihariense A. Kern. and the Antioxidant Activity of the Extract

Melampyrum bihariense A. Kern. (Scrophulariaceae), a plant species used in traditional medicine for the treatment of rheumatic disorders and skin infections, was investigated with regard to its antioxidant activity and identification of its bioactive chemical constituents. The crude methanolic extract of the aerial parts of M. bihariense was examined by the spectrophotometric DPPH (1,1-diphenyl-2-picrylhydrazyl) and ferric reducing antioxidant power methods. The free radical scavenging capacity (SC₅₀) of the extract was found by the DPPH method to be 27.10 mg mL⁻¹, and the ferric reducing ability equivalent to ascorbic acid at 50 mg mL⁻¹ was 0.709 μg mL⁻¹. The chemical composition of this highly effective in the methanolic extract was analysed, and the main compounds were isolated through solvent–solvent partition, and multiple chromatographic separations, including column chromatography, vacuum liquid chromatography, centrifugal planar chromatography and preparative thin-layer chromatography. The structures were established by one- and two-dimensional NMR and liquid chromatography-mass spectrometry. The iridoids aucubin (1), 8-epi-loganin (2) and mussaenoside (3), the flavones apigenin and luteolin and the triterpene acids ursolic acid and oleanolic acid were identified; components 2, 3, ursolic acid and oleanolic acid for the first time in this species. The present study reveals that M. bihariense exerts antioxidant activity, and the iridoids, flavonoids and triterpene acids may be the main bioactive constituents of its methanolic extract.

     

Effects of Extraction Technique on the Content and Antioxidant Activity of Flavonoids from Gossypium Hirsutum linn. Flowers

Cotton is one of the Uyghur medical materials in China and is rich in flavonoids. Flavonoids have important pharmacological effects. The yield of flavonoids in traditional extraction methods is low, which affects the development of flavonoids. Therefore, it is urgent to optimize the extraction techniques. The yield of flavonoids in cotton flowers was effectively improved by response surface methodology, and the highest yield of flavonoids reached 5.66%, and the optimal extraction process conditions were obtained. The DPPH free radical scavenging rate, hydroxyl free radical scavenging rate, superoxide anion free radical scavenging rate, and reducing ability were tested to reflect the antioxidant capacity of flavonoids. The flavonoids had an excellent antioxidant effect. Cell experiments suggested that the flavonoids had the effect of protecting glutamate-induced damage to HT-22 cells. The results of this study provide a theoretical basis for the extraction of cotton flowers flavonoids and the comprehensive evaluation of antioxidant products, as well as the extraction of other plant flavonoids.     

Chemical Composition,Antioxidant and Antimicrobial Activity of Some Types of Honey from Banat Region,Romania

Honey is a natural product with multiple health benefits. The paper presents the chemical characterization and the antioxidant and antimicrobial potential of ten types of honey (knotweed, linden, wild cherry, acacia, honeydew, oilseed rape, sunflower, phacelia, plain polyflora and hill polyflora) from the Banat region, Romania. We studied the water content, dry matter, impurities, acidity and pH of honey. We also determined the content of reducing sugar, minerals and flavonoids and the total phenolic content. All honey samples analysed showed good nutritional characteristics according to the standard codex for honey. From the analysis of the mineral content of the honey samples, we observed a variability in the macro and microminerals, influenced by the botanical origin, ranging between 0.25% (wild cherry honey) and 0.54% (honeydew). The toxic metals’ (Cd and Pb) levels met the standard for almost all samples analysed except for knotweed. The flavonoid content of the samples ranged from 9.29 mg QE/100 g for wild cherry honey to 263.86 mg QE/100 g for linden honey, and for polyphenols between 177.6 mgGAE/100 g for acacia honey and 1159.3 mgGAE/100 g for honeydew. The best antioxidant capacity was registered in the case of linden honey (79.89%) and honeydew (79.20%) and the weakest in acacia (41.88%) and wild cherries (50.4%). All studied honey samples showed antimicrobial activity, depending on the type of honey, concentration and strain analysed. The novelty of this study is given by the complex approach of the study of honey quality, both from the perspective of chemical attributes and the evaluation of the antimicrobial potential on specific strains in correlation with the botanical and geographical origin of the analyzed area.     

Identification of Iridoids,Flavonoids and Triterpenes from the Methanolic Extract of Melampyrum bihariense A. Kern. and the Antioxidant Activity of the Extract

Melampyrum bihariense A. Kern. (Scrophulariaceae), a plant species used in traditional medicine for the treatment of rheumatic disorders and skin infections, was investigated with regard to its antioxidant activity and identification of its bioactive chemical constituents. The crude methanolic extract of the aerial parts of M. bihariense was examined by the spectrophotometric DPPH (1,1-diphenyl-2-picrylhydrazyl) and ferric reducing antioxidant power methods. The free radical scavenging capacity (SC₅₀) of the extract was found by the DPPH method to be 27.10 mg mL^?1, and the ferric reducing ability equivalent to ascorbic acid at 50 mg mL^?1 was 0.709 μg mL^?1. The chemical composition of this highly effective in the methanolic extract was analysed, and the main compounds were isolated through solvent–solvent partition, and multiple chromatographic separations, including column chromatography, vacuum liquid chromatography, centrifugal planar chromatography and preparative thin-layer chromatography. The structures were established by one- and two-dimensional NMR and liquid chromatography-mass spectrometry. The iridoids aucubin (1), 8-epi-loganin (2) and mussaenoside (3), the flavones apigenin and luteolin and the triterpene acids ursolic acid and oleanolic acid were identified; components 2, 3, ursolic acid and oleanolic acid for the first time in this species. The present study reveals that M. bihariense exerts antioxidant activity, and the iridoids, flavonoids and triterpene acids may be the main bioactive constituents of its methanolic extract.