Evaluation of antioxidant,antibacterial and anti-tyrosinase activities of four Macaranga species

The methanolic fresh leaf extracts of Macaranga gigantea, Macaranga pruinosa, Macaranga tanarius and Macaranga triloba were screened for their antioxidant properties (AOP), tyrosinase inhibition and antibacterial activities. Total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferric-ion reducing power (FRAP), ferrous-ion chelating (FIC) and lipid peroxidation inhibition (LPI) activities were used to evaluate the AOP. Modified 3,4-dihydroxy-L-phenylalanine (L-DOPA) method was used to determine tyrosinase inhibition activity, whereas antibacterial activity was determined using the disc-diffusion technique. TPC screening of the same species from different collection sites showed no significant difference between sites. M.triloba showed the highest ascorbic acid equivalent antioxidant activity (AEAC), FRAP and LPI values. M. tanarius, which showed the lowest TPC, AEAC, FRAP and LPI activities, exhibited the best FIC activity. M. pruinosa showed the best tyrosinase inhibition activity, whereas M. triloba showed the best antibacterial activity against Gram-positive bacteria species, with minimal inhibition dosage (MID) values as low as 10 μg/disc.     

Herbal infusions bioelectrochemical polyphenolic index: Green tea – The gallic acid interference

An amperometric biosensor containing immobilised laccase from Trametes versicolor was used for the quantification of phenolic compounds in herbal infusions and green tea samples, from nine botanical families. The main purpose of this research was to correlate the bioelectrochemical polyphenolic index (BPI) of the samples with the total phenolic content according to the Folin–Ciocalteu spectrophotometric method (TPC), and the total antioxidant activity (TAA) measured by TEAC (Trolox Equivalent Antioxidant Capacity). A strong correlation between BPI, TPC, and TAA was obtained for 10 herbal infusion samples. However, when a green tea sample was taken into account, a decrease in the linear correlation coefficient (r²) from 0.9949 to 0.2599 and 0.5609 to 0.1086 for the relationship between BPI/TPC and BPI/TAA, respectively, was observed. Thus, we could conclude that the green tea’s matrix affects the laccase-based biosensor response. HPLC–DAD analysis showed the presence of gallic acid only in the green tea sample. The results have indicated that gallic acid inhibited the laccase activity regarding the ABTS oxidation in a concentration-dependent manner. The very strong correlation between BPI/TPC obtained for herbal infusions allow us to conclude that the laccase-based biosensor, used in this research, provides a valuable tool to obtain a valid estimation of the classical Folin–Ciocalteu index, in an uncomplicated and fast way.     

Evaluation of a loop-mediated isothermal amplification assay for rapid and simple detection of Vibrio parahaemolyticus in naturally contaminated seafood samples

We investigated the efficacy of a loop-mediated isothermal amplification (LAMP) assay for rapid screening of seafood samples naturally contaminated with Vibrio parahaemolyticus. A total of 171 seafood samples enriched in alkaline peptone water (APW) were assessed by LAMP assay and conventional culture methods, which consist of a combination of APW enrichment culture and plating onto CHROMagar Vibrio and TCBS agars. Compared with V. parahaemolyticus isolation using the conventional culture test, LAMP results showed 100% (30/30) and 90.8% (128/141) sensitivity and specificity, respectively. The conventional culture test required more than 3 days to isolate and identify V. parahaemolyticus in the APW enrichment culture. In contrast, the LAMP assay was markedly faster, requiring less than 60 min from the beginning of DNA extraction to final detection of V. parahaemolyticus. In total, the LAMP assay required 17-19 h from the beginning of enrichment culture to final determination. This is the first report of the LAMP assay for rapid screening of seafood samples naturally contaminated by V. parahaemolyticus.     

Chemical composition and biological activities of Algerian Thymus oils

The compositions of essential oils isolated from nine samples of three Thymus species (Thymus algeriensis, Thymus pallescens and Thymus dréatensis) were analysed by GC and GC–MS, and a total of 114 components were identified. T. pallescens collected from various regions showed a great similarity in their compositions and were characterised by carvacrol (44.4–57.7%), p-cymene (10.3–17.3%) and γ-terpinene (10.8–14.2%) as the major components for four samples; only one sample was thymol-rich (49.3%) with a small amount of carvacrol (9.0%). On the other hand, T. algeriensis showed a chemical polymorphism, even for samples from the same location, and two new chemotypes for this species were proposed. Oxygen-containing monoterpenes were the predominant class (76.3%) in T. dreatensis oil, with linalool (30.4%), thymol (20.2%) and geraniol (19.6%) as the principal constituents. The oils were screened for their possible antioxidant activities by four complementary assays, namely DPPH free radical scavenging, hydroxyl radical scavenging, inhibition of lipid peroxidation and reducing power. The two new chemotypes of T. algeriensis exhibited strong hydroxyl radical scavenging (IC₅₀ = 2.2–3.3 μg/ml), but were not or only slightly active against the other radicals and exhibited a weak reducing power. Despite their chemical similarity, T. pallescens oils sometimes produced significant differences in their antioxidant activities. The essential oils were also screened for their antimicrobial activity against five bacteria (three Gram-positive and two Gram-negative) and one yeast (Candida albicans). The tested essential oils showed antimicrobial activity against the microorganisms used, in particular against two important pathogens, C. albicans and Helicobacter pylori.     

Evaluation of lactic acid bacteria and yeast diversity in traditional white pickled and fresh soft cheeses from the mountain regions of Serbia and lowland regions of Croatia

The goal of this study was the characterisation of indigenous lactic acid bacteria (LAB) and yeasts isolated from nine white pickled (BG) and nine fresh soft (ZG) artisanal cheeses collected in Serbia and Croatia. While LAB were present in all of the cheeses collected, yeasts were found in all BG cheeses but only in three ZG cheese samples. High LAB and yeast species diversity was determined (average H′_L = 0.4 and H′_Y = 0.8, respectively). The predominant LAB species in white pickled (BG) cheeses were Lactococcus lactis, Lactobacillus plantarum, and Leuconostoc mesenteroides, while in fresh soft (ZG) cheeses the most dominant LAB species were L. lactis, Enterococcus faecalis, and Leuconostoc pseudomesenteroides. Among the 20 yeast species found, Debaryomyces hansenii, Candida zeylanoides, and Torulaspora delbrueckii were found to be predominant in BG cheeses, while Yarrowia lipolytica was predominant in ZG cheeses. The characterisation of metabolic and technological potentials revealed that 53.4% of LAB isolates produced antimicrobial compounds, 44.3% of LAB strains showed proteolytic activity, while most of the yeast species possessed either lipolytic or proteolytic activity. In conclusion, the results obtained in this study showed that the composition of LAB and yeast populations in white pickled and fresh soft cheeses is region specific. The knowledge gained in this study could eventually be used to select region specific LAB and yeast strains for the production of white pickled and fresh soft artisanal cheeses with geographically specific origins under controlled conditions.     

Phytochemical composition,anti-inflammatory and antitumour activities of four Teucrium essential oils from Greece

The essential oils of four Teucrium species were studied and 150 components, in all, were identified. All oils were rich in sesquiterpenes (50.1–55.8%). Spathulenol and δ-cadinene were the main compounds of Teucrium brevifolium oil; caryophyllene and 4-vinyl guaiacol predominated in Teucrium flavum. Carvacrol and caryophyllene oxide predominated in Teucrium montbretii ssp. heliotropiifolium, while carvacrol and caryophyllene were the most abundant components in Teucrium polium ssp. capitatum. The oil which most effectively inhibited LPS-induced NO production in macrophage cell line RAW 264.7 was that from T. brevifolium (IC₅₀ = 7.1 μg/ml), followed by T. montbretii ssp. heliotropiifolium and T. polium ssp. capitatum (IC₅₀ = 16.5 and 29.4 μg/ml, respectively). The in vitro cytotoxic assay on three human cancer cell lines showed that the most antiproliferative oils were those from T. polium ssp. capitatum and T. montbretii ssp. heliotropiifolium on CACO-2 cell lines (IC₅₀ = 52.7 and 92.2 μg/ml, respectively). The T. brevifolium oil showed a selective cytotoxicity on COR-L23 while significant activity was exerted by T. polium oil on C32.     

Determination of co-metabolism for 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) degradation with enzymes from Trametes versicolor U97

Trametes versicolor U97 isolated from nature degraded 73% of the 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) in a malt extract liquid medium after a 40-d incubation period. This paper presents a kinetic study of microbial growth using the Monod equation. T. versicolor U97 degraded DDT during an exponential growth phase, using glucose as a carbon source for growth. The growth of T. versicolor U97 was not affected by DDT. DDT was degraded by T. versicolor U97 only when the secondary metabolism coincided with the production of several enzymes. Furthermore, modeling of several inhibitors using the partial least squares function in Minitab 15, revealed lignin peroxidase (98.7 U/l) plays a role in the degradation of DDT. T. versicolor U97 produced several metabolites included a single-ring aromatic compound, 4-chlorobenzoic acid.     

变色栓菌来源漆酶的酶学性质及对染料脱色性能的研究

漆酶是一种含铜的多酚氧化酶,能催化多种酚类化合物和芳香族胺氧化,在食品、造纸、能源、高分子化合物合成等领域有着广阔的应用前景。近年对于漆酶的开发利用逐渐受到重视,作者在变色栓菌摇瓶发酵过程中,通过加入法尼醇诱导调控菌丝形态以提高漆酶产量,结果表明,变色栓菌发酵获得的漆酶酶活力和蛋白质质量浓度分别达到（161.37±1.58） U/L和（29.19±1.30） mg/L,均比对照组提高了10倍以上,其最适反应温度为40℃,最适pH为4.0,且在25～55℃有较好的热稳定性。进一步在酶促反应动力学研究基础上,发现漆酶对伊文思蓝、铬黑T、刚果红3种染料均有一定的脱色效果,其中对伊文思蓝的脱色能力最强,具有较好的应用潜力。     

Structural characterisation and antimutagenic activity of a novel polysaccharide isolated from Sepiella maindroni ink

A new heteropolysaccharide, named as SIP, was isolated from the ink of cuttlefish, Sepiella maindroni, by enzymolysis, anion-exchange and gel-permeation chromatography and tested for its antimutagenic activity. It was homogeneous with a molecular weight of 1.13 × 10⁴ Da by HPSEC–MALLS analysis. SIP contained glucuronic acid, mannose, N-acetylgalactosamine, and fucose in a molar ratio of 1:1:2:2. Its structural characteristics were investigated and elucidated by methylation analysis, GLC–MS, and NMR (¹H, ¹³C, H–H COSY, HMQC, HMBC, TOCSY and NOESY). The hexasaccharide repeating unit of SIP was found to be a backbone composed of fucose, N-acetylgalactosamine and mannose in a molar ratio of 2:2:1, and with a single branch of glucuronic acid at the C-3 position of mannose. According to the micronucleus test, SIP could significantly reduce the frequency of micronucleated cells in polychromatic erythrocytes and reticulocytes induced by cyclophosphamide in tumor-bearing mice, which revealed that SIP presented strong antimutagenic activity.     

Effects of Lycium barbarum extract on production and immunomodulatory activity of the extracellular polysaccharopeptides from submerged fermentation culture of Coriolus versicolor

Polysaccharopeptides (PSPs) from Coriolus versicolor have been used as immunomodulatory and anticancer agents. However, most studies have concentrated on the mycelial PSPs and not those in the fermented broth. On the other hand, Lycium barbarum fruit has been used as a traditional Chinese herbal medicine for two millennia. Its extract contains various nutrients, minerals, and also polysaccharide–protein complexes, which are proven to be bioactive. Herein we report the effects of L. barbarum fruit extract on the mycelial growth and extracellular PSP (ePSP) production of C. versicolor LH1 by using a submerged fermentation process in 20 l fermenters. Fermentation production of C. versicolor biomass and its ePSP were augmented in the presence of L. barbarum extract. The ePSP such obtained differs from those obtained with normal culture medium in terms of simple sugar composition and protein content but shows similar overall chemical structures as analyzed by Fourier transformed infrared spectroscopy. Moreover, the ePSP from C. versicolor cultured with supplementary L. barbarum extract exhibits significant immunomodulatory activity as judged by its effects on the production of nitric oxide and several cytokines by murine RAW264.7 macrophages.     

Polyphenols and triterpenes from Chaenomeles fruits: Chemical analysis and antioxidant activities assessment

Mugua, fruit of the genus Chaenomeles, is a valuable source of health food and Chinese medicine. To elucidate the bioactive compounds of five wild Chaenomeles species, extracts from fresh fruits were investigated by HPLC-DAD/ESI-MS/MS. Among the 24 polyphenol compounds obtained, 20 were flavan-3-ols (including catechin, epicatechin and procyanidin oligomers). The mean polymerisation degree (mDP) of procyanidins was examined by two acid-catalysed cleavage reactions; the mDP value was the highest in Chaenomeles sinensis and the lowest in Chaenomeles japonica. Total polyphenol content (TPC) reached 46.92 and 46.28 mg/g gallic acid equivalents (GAE) in Chaenomeles speciosa and Chaenomeles thibetica, respectively, although their main bioactive compounds were different (being epicatechin and procyanidin B2 in the former, and catechin and procyanidin B1 in the latter). These two species also exhibited equally strong free radical scavenging activities. Our results further showed that the antioxidant ability of Chaenomeles fruits was significantly correlated to their total polyphenol contents. Two triterpenes (oleanolic acid and ursolic acid) were the highest quantity in Chaenomeles cathayensis and C. thibetica, respectively.     

Composition and inhibitory activities towards digestive enzymes of polyphenolic-rich fractions of Davidson's plum and quandong

Davidson's plum (DP; Davidsonia pruriens, F. Muell, Cunoniaceae) and quandong (QD; Santalum acuminatum, A.D.C., Santalaceae) are two leading commercially grown native Australian fruits used in a variety of food products such as jam, chutney, sauces, wine or herbal teas. Within this study their inhibitory activities towards key enzymes relevant to metabolic syndrome: α-glucosidase, pancreatic lipase and angiotensin I-converting enzyme were evaluated and compared to these of reference samples: rabbit eye (REB, Vaccinium ashei J.M. Reade) and southern highbush (SHB, Vaccinium darrowii × Vaccinium corymbosum) blueberries. Polyphenolic-rich fraction obtained from DP comprised ellagic acid and ellagitannins accompanied by flavonoids: myricetin, quercetin, rutin, and anthocyanins. This fraction contained the highest level of total phenolics and exhibited superior antioxidant capacity (Ferric Reducing Antioxidant Power, FRAP and Oxygen Radical Absorbance Capacity, ORAC) to polyphenolic-rich fractions of QD, REB and SHB. DP closely followed REB and SHB in their inhibitory activities against isolated α-glucosidase (IC₅₀ of 0.13; 0.097 and 0.091, respectively) and was the most efficient inhibitor of angiotensin converting-enzyme (ACE; 91.2% inhibition at extract concentration of 1 mg/mL). Polyphenolic-rich fraction of QD comprising hydroxycinnamic acids, quercetin and cyanidin 3-glucoside was the most effective inhibitor of pancreatic lipase (IC₅₀: 0.60 mg/mL).     

Biological activities of flavonoids from pathogenic-infected Astragalus adsurgens

The present study was aimed at the identification of biological components from pathogenic-infected Astragalus adsurgens with an activity-guided purification process. Fifteen flavonoids were obtained from the most active ethyl acetate fraction and identified as astradsurnin (1), a new chalcone derivative, together with fourteen known flavonoids (2-15). These compounds were tested for antibacterial activities against five bacteria and cytotoxic activities against two selected cancer cells. Within the series of flavonoids tested, compounds 4 and 15 were the most active against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Erwinia carotovora and Bacillus subtilis with MICs ranging from 7.8 to 31.3 μg/ml. Moreover, compounds 4 and 5 exhibited moderate activity against HL-60 and SMMC-7721 cells with IC₅₀ values between 5 and 10 μg/ml. To our knowledge, this is the first time that it has been reported on the biological and chemical study of A. adsurgens infected by Embellisia astragali.     

Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants

Different parts of three plants (Primula auriculata, Fumaria vaillantii and Falcaria vulgaris) were extracted with three different solvents to yield 72 crude extracts. The phytochemical analysis (chemical screening, GC–MS) of three plants was investigated for their antioxidant and antibacterial activity using nine Gram-positive and Gram-negative bacteria. The principal antioxidant and antimicrobial components were determined using HPLC with UV detection. All extracts possessed antibacterial activity especially methanolic extracts from flowers of P. auriculata. The DPPH-radical scavenging assay exhibited high antioxidant activities in three plants (more than 80% at 50 μg). The F. vulgaris showed high content of carvacrol (29.8%) as main component. The contents of carvacrol and fumaric acid in the methanolic–water extracts were 1119 and 1966 mg/l respectively. Our results indicate that these plants would be able to promise sources of natural products with potential antibacterial and antioxidant activity.     

Effect of muscle and post-mortem rate of pH and temperature fall on antioxidant enzyme activities in beef

The aim of this study was to investigate the effect of muscle, inner and outer Musculus biceps femoris (IBF and OBF respectively) and Musculus longissimus dorsi (LD), on the post-mortem rate of pH and temperature fall, and the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during simulated retail display. At day 0 of display (2 days post-mortem), the CAT and GSH-Px activities were lower in IBF than in OBF and LD (P < 0.001), and the SOD activity was lower in OBF compared to IBF and LD (P < 0.001). At day 10 of display, SOD and CAT activities had decreased in all three muscles compared to day 0 (P < 0.001), whereas the GSH-Px activity did increase with time of display. Across muscles, there were significant relationships between temperature fall, colour, lipid and colour stability and antioxidant enzyme activities.     

Essential oils of Zingiber officinale var. rubrum Theilade and their antibacterial activities

The essential oils obtained by hydrodistilation of the leaves and rhizomes of Zingiber officinale var. rubrum Theilade were analysed by capillary GC and GC–MS. Forty-six constituents were identified in the leaf oil, while 54 were identified in the oil from the rhizomes. The leaf oil was clearly dominated by β-caryophyllene (31.7%), while the oil from the rhizomes was predominantly monoterpenoid, with camphene (14.5%), geranial (14.3%), and geranyl acetate (13.7%) the three most abundant constituents. The evaluation of antibacterial activities using the micro-dilution technique revealed that both the leaf and rhizome oils were moderately active against the Gram-positive bacteria Bacilluslicheniformis, Bacillus spizizenii and Staphylococcus aureus, and the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Pseudomonas stutzeri.     

Evaluation of antioxidant activities of various solvent extracts of Carissa opaca fruits

The chloroform and aqueous fractions of Carissa opaca fruit, a traditional medicinal fruit in Pakistan possessed a high amount of total phenolic and flavonoid contents as compare to other solvent fractions with potent antioxidant activities in scavenging DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, and had strong iron chelating activity. On the other hand, the ethyl acetate fraction showed the highest inhibition of β-carotene linoleic acid peroxidation and phosphomolybdate assay. A high correlation coefficient existed between EC₅₀ values of DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, total phenolics and flavonoids, but a non significant correlation was found in the case of iron chelaters, β-carotene and phosphomolybdate assay. This study verified that the chloroform and aqueous fractions have strong antioxidant activities which were correlated with its high level of phenolics and flavonoids. These fractions can be used as a source of potential antioxidant or functional food material.     

Antioxidant activities of Salvia miltiorrhiza and Panax notoginseng

Traditional Chinese medicinal herb Salvia miltiorrhiza (SM) and Panax notoginseng (PN) have been widely used for the prevention and treatment of vascular diseases in the clinics. To better understand their mechanisms of pharmacological actions, the in vitro antioxidant activities of extract of Salvia miltiorrhiza (ESM) and extract of Panax notoginseng (EPN) were evaluated with different antioxidant testing systems. Their activities of scavenging superoxide anion radicals, DPPH radicals, hydroxyl radicals, and hydrogen peroxide, chelating Ferrous ion, and ferric ion reducing power were assessed. The results showed that the mechanisms of their antioxidant effects were distinct and diverse. ESM possessed strong reducing power and high scavenging activities against free radicals including superoxide anion, hydroxyl and DPPH radicals, but a weaker scavenging activity for hydrogen peroxide. ferrous ion chelating activity of ESM was undetectable at the tested concentrations. In contrary, EPN exhibited strong ferrous ion chelating activity and high scavenging activities against hydrogen peroxide, hydroxyl radicals, and a weak activity against superoxide anion and DPPH free radicals. EPN did not show any ferric ion reducing power. Since their antioxidant mechanisms are complementary, the combined use of ESM and EPN might be even more beneficial. These antioxidant properties of SM and PN are likely part of the reasons that they are effective in the prevention and treatment of vascular diseases.     

Antioxidant activities of Sechium edule (Jacq.) Swartz extracts

The antioxidant activities (AA) of Sechium edule extracts were tested by three established in vitro methods, namely reducing power, β-carotene linoleate model and 1,1- diphenyl-2 picrylhydrazyl (DPPH) radical-scavenging. Leaf ethanolic extracts and leaf and seed water extracts showed strong inhibitory activity by β-carotene bleaching (AA values of 90%). Furthermore, these extracts exerted hydrogen-donating ability in the presence of DDPH stable radical (IC₅₀ 2 μg/ml). These extracts also showed strong reducing power by the potassium ferricyanide reduction method. Leaf and seed extracts may be exploited as biopreservatives in food applications as well as for health supplements or functional food, to aleviate oxidative stress.