Metabolome of Ceratodon purpureus (Hedw.) Brid., a cosmopolitan moss: the influence of seasonality.

MAIN CONCLUSION: Ceratodon purpureus showed changes in disaccharides, flavonoids, and carotenoids throughout annual seasons. These changes indicate harsher environmental conditions during the dry period, directing metabolic precursors to enhance the antioxidant system. Bryophytes are a group of land plants comprising mosses (Bryophyta), liverworts (Marchantyophyta), and hornworts (Antocerotophyta). This study uses the molecular networking approach to investigate the influence of seasonality (dry and rainy seasons) on the metabolome and redox status of the moss Ceratodon purpureus (Hedw.) Brid., from Campos do Jordão, Brazil. Samples of C. purpureus were submitted to three extraction methods: 80% methanol producing the soluble fraction (intracellular compounds), followed by debris hydrolysis using sodium hydroxide producing the insoluble fraction (cell wall conjugated compounds), both analyzed by HPLC-MS; and extraction using pre-cooled methanol, separated into polar and non-polar fractions, being both analyzed by GC-MS. All fractions were processed using the Global Natural Product Social Molecular Network (GNPS). The redox status was assessed by the analysis of four enzyme activities combined with the analysis of the contents of ascorbate, glutathione, carotenoids, reactive oxygen species (ROS), and malondialdehyde acid (MDA). During the dry period, there was an increase of most biflavonoids, as well as phospholipids, disaccharides, long-chain fatty acids, carotenoids, antioxidant enzymes, ROS, and MDA. Results indicate that C. purpureus is under harsher environmental conditions during the dry period, mainly due to low temperature and less water availability (low rainfall).

Multifaceted roles of nitric oxide in tomato fruit ripening: NO-induced metabolic rewiring and consequences for fruit quality traits.

Nitric oxide (NO) has been implicated as part of the ripening regulatory network in fleshy fruits. However, very little is known about the simultaneous action of NO on the network of regulatory events and metabolic reactions behind ripening-related changes in fruit color, taste, aroma and nutritional value. Here, we performed an in-depth characterization of the concomitant changes in tomato (Solanum lycopersicum) fruit transcriptome and metabolome associated with the delayed-ripening phenotype caused by NO supplementation at the pre-climacteric stage. Approximately one-third of the fruit transcriptome was altered in response to NO, including a multilevel down-regulation of ripening regulatory genes, which in turn restricted the production and tissue sensitivity to ethylene. NO also repressed hydrogen peroxide-scavenging enzymes, intensifying nitro-oxidative stress and S-nitrosation and nitration events throughout ripening. Carotenoid, tocopherol, flavonoid and ascorbate biosynthesis were differentially affected by NO, resulting in overaccumulation of ascorbate (25%) and flavonoids (60%), and impaired lycopene production. In contrast, the biosynthesis of compounds related to tomato taste (sugars, organic acids, amino acids) and aroma (volatiles) was slightly affected by NO. Our findings indicate that NO triggers extensive transcriptional and metabolic rewiring at the early ripening stage, modifying tomato antioxidant composition with minimal impact on fruit taste and aroma.

UV-B and Drought Stress Influenced Growth and Cellular Compounds of Two Cultivars of Phaseolus vulgaris L. (Fabaceae).

Combined enhanced UV-B radiation and drought may induce different morphological and physiological alterations in plants than either abiotic stress alone. We evaluated morphology, biomass, and primary and secondary metabolism changes in seedlings of two common bean cultivars, IAC Imperador (drought-resistant) and IAC Milênio. To test the hypothesis that cultivars responded differently to combined stresses in a controlled environment, seedlings of the examined been cultivars were exposed to UV-B and/or drought treatments for three weeks. The cultivars behaved differently, especially to the drought treatment, suggesting that they use different mechanisms to cope with unfavorable environmental conditions. IAC Imperador showed a stronger protective response, modifying wax composition and primary metabolism, and improving its resistance to UV-B radiation. For IAC Imperador, the accumulation of cuticular wax and alkane was higher under combined stress but production of primary alcohols was reduced, suggesting a possible fatty acyl switch. Root/shoot length and biomass ratios increased in both cultivars, particularly for the combined stress, indicating a common plant response. We show that these two bean cultivars responded more strongly to UV-B and combined stress than drought alone as evident in changes to their chemistry and biology. This shows the importance of investigating plant morphological and physiological responses to combined stress.

Antiproliferative activity of flavonoids from Croton sphaerogynus Baill. (Euphorbiaceae).

Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days), was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1-F5) containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1-F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung), MCF-7 (breast cancer), and U251 (glioma). The MeOH phase showed activity (mean log GI50 0.54) higher than the hexane phase and EtOH extract (mean log GI50 1.13 and 1.19, resp.). F1 exhibited activity against NCI-H460 (nonsmall cell lung) (GI50 1.2 µg/mL), which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI50 1.05), while F5 showed weak activity (mean log GI50 1.36). It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes.

Searching for native tree species and respective potential biomarkers for future assessment of pollution effects on the highly diverse Atlantic Forest in SE-Brazil.

This study summarizes the first effort to search for bioindicator tree species and respective potential biomarkers for future assessment of potential mixed pollution effects on the highly diverse Atlantic Forest in SE-Brazil. Leaves of the three most abundant species inventoried in a phytosociological survey (Croton floribundus, Piptadenia gonoacantha and Astronium graveolens) were collected in four forest remnants during winter and summer (2012). Their potential bioindicator attributes were highlighted using a screening of morphological, chemical and biochemical markers. The leaf surface structure and/or epicuticular wax composition pointed the accumulator properties of C. floribundus and P. gonoacantha. C. floribundus is a candidate for assessing potential accumulation of Cu, Cd, Mn, Ni, S and Zn. P. gonoacantha is a candidate to monitor polycyclic aromatic hydrocarbons. Increased levels of secondary metabolites and decreased antioxidant capacity in leaves of A. graveolens may support its value as a bioindicator for oxidative pollutants by visible dark stipplings.

Antiproliferative activity of methanol extracts of four species of Croton on different human cell lines

Several species of Croton have been described with biological activities, mainly due to diterpenes, alkaloids and/or other secondary metabolites. These activities account for the traditional use of Croton species to treat certain diseases in South America, Asia and Western Africa. The crude methanol extracts obtained from leaves and steam bark of Croton dichrous Müll. Arg., C. erythroxyloides Baill., C. myrianthus Müll. Arg. and C. splendidus Mart. ex Colla were tested for antiproliferative activity against ten human cancer cell lines. Chemical analyses of all extracts were carried out by GC/MS and HPLC/MS/MS. The leaf extract obtained from C. erythroxyloides showed potent activity against PC-3 (prostate) and OVCAR-3 (ovary) cell lines. Lupeol is suggested to be involved in such activity. Tiliroside, an acyl-glycosilated flavonoid ubiquitous in all tested extracts, seems to play an important role in the observed moderate activity of most extracts against the leukemia K562 cell lineage.

Chemical composition and efficacy of dichloromethane extract of Croton sphaerogynus Baill. (Euphorbiaceae) against the cattle tick Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus microplus is widely distributed in tropical and subtropical regions, causing high economic impact on cattle production. The control of tick infestations is regarded worldwide as critical and has been based on the use of organophosphates, synthetic pyretroids, amitraz and recently ivermectin and fipronil. The present study reports the analysis by gas chromatography/mass spectrometry of the constituents of leaf extracts of Croton sphaerogynus and results of acaricidal activity against the cattle tick R. microplus. The larval package test using the serial dilutions 0.625%, 1.25%, 2.5%, 5.0%, 10.0% and 20.0% (v/v) gave mortality rates 2.25%, 8.26%, 8.81%, 24.80%, 83.66% and 99.32%, respectively. Relevant constituents identified were abietanes, podocarpenes and clerodane type furano diterpenes. The present work may represent a possibility of attainment of natural substances useful for the control of R. microplus.

Constituents and antiproliferative activity of extracts from leaves of Croton macrobothrys

Croton macrobothrys Baill, Euphorbiaceae, is a tree from the Atlantic Forest in Southern Brazil, used in traditional medicine and popularly known as "dragon's blood" and "pau-sangue". Leaf n-hexane, dichloromethane and methanol extracts were analyzed by GC/MS and evaluated for their in vitro antiproliferative activity on cell lines 786-0 (kidney), HT-29 (colon), K562 (leukemia), NCI-ADR/RES (drug resistant ovary), NCI-H460 (lung), MCF-7 (mammary), PC-3 (prostate), OVCAR-3 (ovary), U251 (glioma) and UACC-62 (melanoma). The dicloromethane extract exhibited activity against all cell lines at the concentration 25 µg/mL, in particular on cell lines NCI-H460 (GI50 0.33 μg/mL) and K5662 (GI50 0.91 μg/mL). Relevant constituents in dichloromethane extract are the alkaloids corydine and salutaridine, as well as the diterpenes geranylgeraniol and crotonin-derived clerodanes.

Tibouchina pulchra (Cham.) Cogn., a native Atlantic Forest species, as a bio-indicator of ozone: visible injury.

Tibouchina pulchra saplings were exposed to carbon filtered air (CF), ambient non-filtered air (NF) and ambient non-filtered air+40 ppb ozone (NF+O3) 8 h per day during two months. The AOT40 values at the end of the experiment were 48, 910 and 12,895 ppb h(-1), respectively, for the three treatments. After 25 days of exposure (AOT40=3871 ppb h(-1)), interveinal red stippling appeared in plants in the NF+O3 chamber. In the NF chamber, symptoms were observed only after 60 days of exposure (AOT40=910 ppb h(-1)). After 60 days, injured leaves per plant corresponded to 19% in NF+O3 and 1% in the NF treatment; and the average leaf area injured was 7% within the NF+O3 and 0.2% within the NF treatment. The extent of leaf area injured (leaf injury index) was mostly explained by the accumulated exposure of ozone (r2=0.89; p<0.05).

Physiological responses of saplings of Caesalpinia echinata Lam., a Brazilian tree species, under ozone fumigation.

The effects induced by long-term (30 day) and short-term (6h) exposures to ozone on the physiological parameters in young plants of Caesalpinia echinata Lam., a Brazilian tree species, were determined. Potted plants were maintained in open-top chambers in Valencia, Spain, under charcoal filtered air (mean O3 level: 29 microg m3), nonfiltered air (NF; 43 microg m3), and nonfiltered air plus O3 (NF + O3; 68 microg m3), simulating prevailing concentrations observed in the city of São Paulo, Brazil, during spring months (50 microg m3 in 2002). In the plants kept in NF + O3 for 30 days, although no foliar visible injuries were observed, the net carbon assimilation rate was reduced to 50%, stomatal conductance 42%, and transpiration 40%, when compared to the results for the NF plants. No changes in antioxidants, in leaf, stem, and root biomass, and in the root/shoot ratio were observed. Significant reductions were observed in gas exchange and in PSII photochemical efficiency (Fv/Fm) after 6 h of exposure to an O3 peak. The species was shown to be sensitive to ambient O3 concentrations measured in São Paulo.