Evaluation of flavonoids from <Emphasis Type="Italic">Zostera asiatica</Emphasis> as antioxidants and nitric oxide inhibitors

Zostera asiatica is one of the five members of the genus Zostera that can be found in Korea. Studies have reported the phytochemical properties and bioactivities of Zostera species. Current study focused on the antioxidant effects of Z. asiatica as a part of ongoing research for bioactive substances from marine resources. Results indicated that a crude extract of Z. asiatica not only scavenged on peroxynitrite in vitro and on intracellular reactive oxygen species (ROS) but also inhibited production of nitric oxide (NO). The crude extract was subjected to solvent fractionation for bioactivity-based separation using aforementioned three bioassay systems. From the active n-butanol fraction, two flavonoids were isolated and characterized as luteolin (1) and luteolin-3’-sulfate (2). Both flavonoids showed significant antioxidant effects. In conclusion, Z. asiatica was demonstrated to possess antioxidant effect partly attributed to isolated flavonoids, the first such effect reported from Z. asiatica, to the best of our knowledge.     

Bioactive compounds from marine <Emphasis Type="Italic">Streptomyces</Emphasis> sp. VITPSA as therapeutics

Background

Marine actinomycetes are efficient producers of new secondary metabolites that show different biological activities, including antibacterial, antifungal, anticancer, insecticidal, and enzyme inhibition activities.

Methods

The morphological, physiological, and biochemical properties of the strain Streptomyces sp. VITPSA were confirmed by conventional methods. Antibacterial, anti-oxidant, anti-inflammatory, anti-diabetic, and cytotoxic activities of Streptomyces sp. VITPSA extract were determined. The media were optimized for the production of secondary metabolites. Characterization and identification of secondary metabolites were conducted by high-performance liquid chromatography, gas chromatography-mass spectroscopy, and Fourier transform infrared spectroscopy analysis.

Results

The strain showed significant antibacterial, anti-oxidant, and cytotoxic activities, moderate anti-inflammatory activity, and no satisfactory anti-diabetic activity. The ethyl acetate extract of Streptomyces sp. VITPSA showed maximum antibacterial activity against two gram-positive and gram-negative bacteria at 0.5 mg/mL. The antioxidant potential of the crude extract exhibited strong reducing power activity at 0.5 mg/mL with 95.1% inhibition. The cytotoxic effect was found to be an IC₅₀ of 50 μg/mL on MCF-7 cell lines. Experimental design of optimization by one-factor analysis revealed the most favorable sucrose, yeast extract, pH (7.25), and temperature (28°C) conditions for the effective production of secondary metabolites.

Conclusion

This study revealed that Streptomyces sp. VITPSA is an excellent source of secondary metabolites with various bioactivities.

     

Phytochemistry and bioactivity of <Emphasis Type="Italic">Citrus</Emphasis> flavonoids: a focus on antioxidant,anti-inflammatory,anticancer and cardiovascular protection activities

Epidemiological studies have suggested an inverse relationship between increased consumption of fruits and reduced risk of chronic diseases, such as cardiovascular diseases, cancer, and diabetes. Citrus fruit is one of the mostly consumed fruits worldwide, and numerous studies have revealed its remarkable health-promoting activities, such as antioxidant, anticancer, anti-inflammatory, and cardiovascular protection activities. These activities largely depend upon the diverse chemical constituents of Citrus fruits, including vitamins, minerals, terpenoids, and flavonoids. Notably, dietary flavonoids occurring in Citrus fruits have attracted growing interest due to their distinct beneficial effects on human health. In this review, we outlined the main health-related properties of Citrus flavonoids, with a focus on antioxidant, anticancer, anti-inflammation, and cardiovascular protection activities. Also the bioavailability, a critical factor that influences the biological efficacy, of Citrus flavonoids was discussed. It was believed that insights about these advances may encourage researchers to discover new phytochemical components and further study specific bioactivities from Citrus fruits.     

Phylogeny,antimicrobial, antioxidant and enzyme-producing potential of fungal endophytes found in <Emphasis Type="Italic">Viola odorata</Emphasis>

Viola odorata, a medicinal plant, is traditionally used to treat common cold, congestion and cough. Given its medicinal properties and occurrence in the northwestern Himalayas, we isolated and characterized endophytic fungi from this plant morphologically, microscopically and by internal transcribed spacer-based rDNA sequencing. In total, we isolated 27 morphotypes of endophytes belonging to phyla Ascomycota and Basidiomycota. The roots showed the highest diversity of endophyte as well as fungal dominance, followed by leaves and leaf nodes. The fungal extract of VOR16 (Fusarium oxysporum) displayed potent antimicrobial activity against Salmonella typhimurium, Klebsiella pneumoniae and Escherichia coli, with a minimum inhibitory concentration of 0.78, 0.78 and 1.56 μg/mL, respectively, while fungal extract VOLF4 (Aspergillus sp.) exhibited promising antioxidant activity (IC₅₀ of 17.4 μg/mL). To identify the components responsible for various bioactivities, we analyzed the content of penicillin G in the extract of bioactive endophytes. The results suggested that the expression of penicillin G under the fermentation conditions applied was too low to display antimicrobial effects. Thus, the activity may be contributed by a different, novel secondary metabolite. The antioxidant activity of VOLF4 may be attributed to its high content of flavonoids. Of the endophytic fungi assessed, 27% were found to be enzyme producers. The highest zone of clearance was observed in VOLN5 (Colletotrichum siamense) for protease production. Only VOR5 (Fusarium nematophilum) was found to be a producer of cellulase, glutenase, amylase and protease. In summary, this is the first report of the isolation of endophytes, namely Fusarium nematophilum, Colletotrichum trifolii, C. destructivum, C. siamense and Peniophora sp., from V. odorata and their bioactive and enzyme-producing potential.     

Isolation and characterization of trichalasin-producing endophytic fungus from <Emphasis Type="BoldItalic">Taxus baccata</Emphasis>

An endophytic fungus (strain T1) isolated from Taxus baccata was studied for the production of metabolites with anticancer and antioxidant activities. This fungus was identified as Diaporthe sp. based on rDNA-internal transcribed spacer (ITS) sequence analysis. The crude extract showed cytotoxic activity against MCF-7 and HeLa cancer cell lines, with IC₅₀ (concentration inhibiting 50% of growth rate) values of 1058?±?44 and 1257?±?80 μg ml^?1, respectively. The scavenging activity of fungal extract increased significantly with increasing concentration [IC₅₀ (concentration required to scavenge 50% of free radicals) 482?±?9 μg ml^?1]. Ultra-high-performance liquid chromatography-quadrupole-time of flight analysis revealed the presence of three trichalasins (trichalasin E, F and H) in the crude extract of T1 which are known to have antitumour and antioxidant activities. These results suggest that Diaporthe sp. has the potential to be used for therapeutic purposes because of its antiproliferative and antioxidant potential and also for the production of cytochalasins.     

Genome size and ploidy level among wild and cultivated <Emphasis Type="Italic">Prunus</Emphasis> taxa in Slovakia

2C DNA content and ploidy level variation of Prunus spinosa and closely related taxa together with Prunus domestica L. and Prunus insititia L. was studied in Slovakia. The aim of the study was to define genome sizes and find differences between closely related taxa within Prunus spinosa sensu lato mentioned in previous works. According to our results, investigated taxa can be divided into three groups according to ploidy level: Prunus spinosa, Prunus dasyphylla, Prunus ×fruticans, Prunus ×dominii and Prunus ×schurii are tetraploids, Prunus ×fechtneri is pentaploid, and P. domestica and P. insititia are hexaploids. Genome size differences within tetraploid taxa were relatively small (Prunus spinosa: 1.40?±?0.02, P. ×domini: 1.44?±?0.01, P. ×fruticans: 1.48?±?0.02, P. ×schurii: 1.44?±?0.02), but statistically significant. Although further research is needed, it seems that the concept of several taxa as product of hybridization between P. spinosa and cultivated plum species has been supported by our study.     

Callus and cell suspension culture of <Emphasis Type="Italic">Viola odorata</Emphasis> as in vitro production platforms of known and novel cyclotides

Callus from Opuntia streptacantha (cv. Tuna loca), Opuntia megacantha (cv. Rubí reina), and Opuntia ficus-indica (cv. Rojo vigor) were exposed to jasmonic acid (JA) and abiotic stress (drought and UV light) to improve the metabolite production. The callus growth curves, phenolic acids and flavonoids content, antioxidant activity and phenylalanine ammonia lyase (PAL) activity were analyzed under normal and stress conditions. In O. streptacantha callus, the phenolics concentration increased 1.6 to 3 times times in presence of 5% PEG or after irradiation with UV light for 240 min, respectively, while flavonoids triplicate with UV light. A significant increase in antioxidant activity was observed in calli from the three Opuntia species in media with 50 µM JA. The relationships between metabolites/PAL activity, and metabolites/antioxidant activity were analyzed using a surface response methodology. Results showed that PAL activity, induced with PEG and UV, correlated with flavonoids content in O. megacantha and O. ficus-indica calli; PAL activity was related to both flavonoids and phenolics compounds in O. ficus-indica and O. megacantha calli exposed to JA, but only to flavonoids in O. streptacantha callus. In general, the JA stimulated simultaneously the metabolic pathways for phenolics and flavonoids synthesis, while abiotic stress induced mainly flavonoids route. As the stressed Opuntia calli exhibited as high antioxidant activity as cladodes, they are a promising system for research on antioxidant biosynthesis and/or to identify new compounds with antioxidant properties.     

Effects of <Emphasis Type="Italic">Ascophyllum nodosum</Emphasis> extract on growth and antioxidant defense systems of two freshwater microalgae

Microalgae in genus Chlorella and Scenedesmus are common in aquatic ecosystems and are widely used for various studies on algal growth and applications. Macroalgae may play an important role for control of microalgal growth, attributable to their rich content of bioactive compounds. In this study, the brown seaweed Ascophyllum nodosum was extracted with 70% acetone and the extract was used to treat the green microalgae, Chlorella vulgaris and Scenedesmus sp. Cell density and chlorophyll a concentration were used as growth indexes to evaluate the effects of A. nodosum extract (ANE) on the microalgae. The ANE with concentrations > 1% exhibited significant capability of inhibition of the growth of microalgae by over 80%. On the contrary, 1% ANE caused varying degrees of acceleration of cell proliferation and chlorophyll a synthesis in C. vulgaris and Scenedesmus sp., respectively. Analysis of antioxidant activities of the enzymes superoxide dismutase (SOD) and catalase (CAT) revealed the impact of ANE on the antioxidant defense system of the microalgae. The SOD and CAT activities were significantly depressed by high concentrations (> 2%) ANE, while a slight increase of the enzyme activities was observed with 1% ANE at the early period, which could be correlated to the growth response. Therefore, the mechanism of microalgae control could be related to the interaction between the ANE and the antioxidant defense systems. Phlorotannins are proposed as the principal algistatic components in the ANE which could be utilized in controlling microalgae growth.     

<Emphasis Type="Italic">Camellia sinensis</Emphasis> increased apoptosis on U2OS osteosarcoma cells and wound healing potential on NIH3T3 fibroblast cells

Camellia sinensis (Cs) is a plant which is rich in polyphenols and has antioxidant, antiinflammatory, antimutagenic, anticarcinogenic and antibacterial activities. In this study, two different methanol extracts (Cs-I and Cs-II) were prepared from the leaf of C. sinensis in order to investigate the wound healing and anticancer activities. Total phenolic content and antioxidant activity of the extracts were determined. Wound healing effects of Cs extracts were evaluated by using Masson’s Trichrome Tecnique on NIH3T3 fibroblast cells. Cytotoxic and apoptotic effects of the extracts were determined by MTT and AnnexinV-PI assays on U2OS osteosarcoma cells. Total phenolic contents and antioxidant activities of the extracts were almost the same. The highest concentration (60 µg/mL) of the extracts showed significant cytotoxic and apoptotic effects on U2OS cells. Especially, the highest apoptotic effect was determined with 60 µg/mL Cs-I extract. Significant wound healing potential on NIH3T3 fibroblast cells were determined especially with low extract concentrations (0.5, 1 and 5 µg/mL), while high extract concentrations showed significant anticancer effects. As a result, two Cs leaf extracts exhibited important apoptotic properties and both have wound healing potential. However, the Cs-I extract was found more effective on apoptotic osteosarcoma cell death and has an increased wound healing potential than the Cs-II extract.     

Radio-protective and antioxidative activities of astaxanthin from newly isolated radio-resistant bacterium <Emphasis Type="Italic">Deinococcus</Emphasis> sp. strain WMA-LM9

A radio-resistant bacterium, designated as strain WMA-LM9, was isolated from desert soil. 16S rRNA gene sequencing indicated that the bacterium belongs to genus Deinococcus with maximum similarity to Deinococcus radiopugnans. Deinococcus sp. strain WMA-LM9 was found to be resistant to a ultraviolet (UV) dose of 5 × 10³ J/m², hydrogen peroxide (50 mM) and mitomycin C (10 μg/ml). A carotenoid pigment was extracted using chloroform/methanol/acetone (7:5:3) and purified by high-performance liquid chromatography on a C₁₈ analytical column. The compound was characterised as mono-esterified astaxanthin by ¹H, ¹³C nuclear magnetic resonance and mass spectrometry. It was tested for antioxidant activity, total flavonoids and phenolic content, radioprotective potential in correlation to the prevention of protein oxidation and DNA strand breaks in vitro. The carotenoid pigment showed a very potent antioxidant activity and significantly stronger scavenging ability against superoxides, with an IC₅₀ (concentration causing 50% inhibition of the desired activity) of 41.6 μg/ml. The total phenolic and flavonoid contents were 12.1 and 7.4 μg in terms of gallic acid and quercetin equivalents per milligram of dried mass, respectively. astaxanthin also showed a higher inhibitory action against oxidative damage to collagen, elastin and bovine serum albumin than did β-carotene. The carotenoid also inhibited breaks to DNA strands, as indicated by the results of the DNA damage prevention assay. We conclude that astaxanthin from Deinococcus sp. strain WMA-LM9 has protective effects against radiation-mediated cell damage, and it also protects cellular protein and DNA against oxidative stress and other anti-oxidant activities.     

Purification and activity characterization of polysaccharides in the medicinal lichen <Emphasis Type="Italic">Umbilicaria tornata</Emphasis> from Taibai Mountain,China

Water-soluble polysaccharides from Umbilicaria tornata (UTP) were purified and preliminarily characterized. The antioxidant and antitumor activities of crude UTP and two purified fractions (UTP-1 and UTP-2) were evaluated using in vitro experiments. The results showed that the molecular weights of UTP-1 and UTP-2 were 84.86 and 28.66 kDa, respectively. Both UTP-1 and UTP-2 were composed of glucose and xylose, with their molar ratios being 1.3:0.9 and 0.9:4.6, respectively. In addition, crude UTP, UTP-1 and UTP-2 showed dose-dependent DPPH and hydroxyl radical scavenging and reducing activities. However, crude UTP exhibited stronger antioxidant activity than UTP-1 and UTP-2, particularly in terms of DPPH radicals. Crude UTP and the two purified fractions inhibited the growth of HeLa, HepG2, A375, MCF-7, SGC7901 and Caco2 cancer cells in vitro. Compared with UTP-1 and UTP-2, crude UTP presented significantly higher antitumor activity in vitro against HeLa and HepG2 cells (p?<?0.05). These findings provide a scientific basis for the deeper exploration and resource development of U. tornata.     

Overexpression of the receptor-like cytoplasmic kinase gene <Emphasis Type="Italic">XCRK</Emphasis> enhances Xoc and oxidative stress tolerance in rice

In this paper, we characterized a differentially expressed receptor-like cytoplasmic kinase XCRK, which confers resistance to bacterial leaf streak (BLS). We analyzed the tissue expression of XCRK and showed that XCRK was widely expressed in multiple rice (Oryza sativa) organs, including internodes, roots, leaves and flowers. In addition, the expression of XCRK was significantly induced by ABA, salt and H₂O₂ treatments, suggesting its function in these pathways. The XCRK-overexpressing transgenic seedlings exhibited higher tolerance to Xanthomonas oryzae pv.oryzicola (Xoc) compared with the wild-type seedlings. Furthermore, XCRK-overexpressing seedlings showed stronger antioxidant capacity with reduced MDA and H₂O₂ content and higher antioxidant enzyme activities. It has been hypothesized that the enhanced Xoc tolerance was attributed to the improved expression of resistance-responsive factors positively regulated by XCRK. In accordance with this, the expression of resistance and oxidation-related genes Wrky77, Wrky13, PAL1, PR5, Fe-SOD and SodCc2 were up-regulated by the overexpression of XCRK, which might contribute collectively to the increased Xoc tolerance. Overall, overexpression of XCRK could enhance the antioxidant capacity and Xoc tolerance in rice.     

Endophytism and bioactivity of endophytic fungi isolated from <Emphasis Type="Italic">Combretum lanceolatum</Emphasis> Pohl ex Eichler

We report the isolation and identification of endophytic fungi from Combretum lanceolatum Pohl ex Eichler. Further, we evaluated the relationships of fungi with the host plant and tested bioactivities of isolates. The fungi were isolated from disinfected root fragments and plated onto potato dextrose agar. Root pieces were also used to quantify fungal structures associated with the roots. Identification of fungi was carried out by characterization of morphological features and sequencing of the ITS region. Endophytism was confirmed by inoculation of endophyte-free seedlings followed by microscopic examination. The extract was obtained by maceration of the mycelium in ethyl acetate for antioxidant and antimicrobial evaluations. A total of 112 strains belonging to nine different species were isolated, the major classes were Dothideomycetes and Sordariomycetes. C. lanceolatum is colonized by dark septate endophytes (DSE), evidenced by the presence of microsclerotia and melanized hyphae. There is also co-colonization with mycorrhizal fungi in the same root fragments. Seedling inoculation experiments revealed that C. perangustum-95C and M. phaseolina-46C showed association with the seedlings of C. lanceolatum and differentiated microsclerotia and dark septate hyphae, indicating that these species are DSE. In the antimicrobial test, the D. phaseolorum-92C extract had the highest zones of inhibition against S. aureus and E. coli, respectively. The results showed that 100 % of the extracts have antioxidant activity ranging from low to moderate. All endophyte species had antioxidant and antimicrobial activities that were directly proportional to the dose-responses. Future research will involve chemical characterization and structural elucidation of bioactive compounds.     

Antioxidant and α-glucosidase inhibitory phenolic constituents of <Emphasis Type="Italic">Lactuca indica</Emphasis> L.

Lactuca indica L. (Compositae) has been used as a folk medicine for the treatment of intestinal disorders. Phytochemical constituents of L. indica were investigated, and their antioxidant and α-glucosidase inhibitory activities thoroughly studied. A phytochemical investigation of the aerial parts of L. indica resulted in the isolation and identification of eight phenolic compounds. The structures of the compounds were elucidated on the basis of spectroscopic evidence as apigenin, luteolin, isoquercitrin, chlorogenic acid, protocatechuic acid, p-hydroxymethyl benzoic acid, trans-cinnamic acid, and p-coumaric acid. Luteolin, isoquercitrin, chlorogenic acid, and p-hydroxymethyl benzoic acid showed antioxidant activities with IC₅₀ values in the range of 35.5–52.5 μM. In addition, apigenin and luteolin showed α-glucosidase inhibition activities with IC₅₀ values of 96.4 and 100.7 μM, respectively. These findings strongly suggest that L. indica is a potential source of natural antioxidants and/or anti-diabetic agents in pharmaceutical and health functional foods.     

Review of five species of cyclocoelids (Digenea: Cyclocoelidae) from aquatic birds in Mexico with notes on their interspecific variation

Based on a morphological approach, five species of cyclocoelids (Digenea: Cyclocoelidae) are revised based on material from birds in Mexico. The species studied are: Cyclocoelum cf. leidyi Harrah, 1922 from the black-necked stilt Himantopus mexicanus Müller (Recurvirostridae); Cyclocoelum mutabile (Zeder, 1800) from the northern jacana Jacana spinosa L. (Jacanidae) and the willet Tringa semipalmata Gmelin (Scolopacidae); Cyclocoelum pseudomicrostomum Harrah, 1922 from the American coot Fulica americana Gmelin (Rallidae); Selfcoelum lamothei Blend & Dronen, 2008, from the long-billed curlew Numenius americanus Bechstein (Scolopacidae); and Neohaematotrephus arayae Zamparo, Brooks, Causey & Rodriguez, 2003 from J. spinosa. New morphological data, illustrations and measurements are presented for these trematodes. Three species, insufficiently described, i.e. C. cf. leidyi, C. mutabile and C. pseudomicrostomum, are redescribed in detail. Our results indicate morphological variation in some important features used in the diagnosis of Cyclocoelum Brandes, 1892 (i.e. the presence or absence of oral sucker, the position of the genital pore relative to the pharynx, and the posterior extension of the uterus) and Selfcoelum Dronen, Gardner & Jiménez, 2006 (i.e. anterior extension of vitelline follicles). Finally, this study provides the first molecular data for the large subunit of the ribosomal RNA (28S rRNA) gene for N. arayae.