Petals of Crocus sativus L. as a potential source of the antioxidants crocin and kaempferol.

Collaboration between Leicester School of Pharmacy - De Montfort Universit, Department of Life, Health and Environmental Sciences - University of L'Aquila, and Department of Biochemistry and Biotechnology - University of Thessaly The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Saffron fromthe province of L'Aquila, in the Abruzzo region of Italy, is highly prized and has been awarded a formal recognition by the European Union with EU Protected Designation of Origin (PDO) status. Despite this, the saffron regions are abandoned by the younger generations because the traditional cultivation of saffron (Crocus sativus L.) is labour intensive and yields only one crop of valuable saffron stamens per year. Petals of the saffron Crocus have had additional uses in traditional medicine and may add value to the crops for local farmers. This is especially important because the plant only flowers between October andNovember, and farmers will need to make the best use of the flowers harvested in this period. Recently, the petals of C. sativus L., which are considered a wastematerial in the production of saffron spice,were identified as a potential source of natural antioxidants. The antioxidants crocin and kaempferol were purified by flash column chromatography, and identified by thin layer chromatography (TLC), HPLC–DAD, infrared (IR), and nuclear magnetic resonance (1H & 13C NMR) spectroscopy. The antioxidant activity was determined with the ABTS and DPPH tests. The antioxidant activities are mainly attributed to carotenoid and flavonoid compounds, notably glycosides of crocin and kaempferol. We found in dried petals 0.6% (w/w) and 12.6 (w/w) of crocin and kaempferol, respectively. Petals of C. sativus L. have commercial potential as a source for kaempferol and crocetin glycosides, natural compounds with antioxidant activity that are considered to be the active ingredients in saffron-based herbal medicine

Trade-Off between Toxicity and Signal Detection Orchestrated by Frequency- and Density-Dependent Genes

Behaviors in insects are partly highly efficient Bayesian processes that fulfill exploratory tasks ending with the colonization of new ecological niches. The foraging (for) gene in Drosophila encodes a cGMP-dependent protein kinase (PKG). It has been extensively described as a frequency-dependent gene and its transcripts are differentially expressed between individuals, reflecting the population density context. Some for transcripts, when expressed in a population at high density for many generations, concomitantly trigger strong dispersive behavior associated with foraging activity. Moreover, genotype-by-environment interaction (GEI) analysis has highlighted a dormant role of for in energetic metabolism in a food deprivation context. In our current report, we show that alleles of for encoding different cGMP-dependent kinase isoforms influence the oxidation of aldehyde groups of aromatic molecules emitted by plants via Aldh-III and a phosphorylatable adaptor. The enhanced efficiency of oxidation of aldehyde odorants into carboxyl groups by the action of for lessens their action and toxicity, which should facilitate exploration and guidance in a complex odor environment. Our present data provide evidence that optimal foraging performance requires the fast metabolism of volatile compounds emitted by plants to avoid neurosensory saturation and that the frequency-dependent genes that trigger dispersion influence these processes

Engineering an aldehyde dehydrogenase toward its substrates, 3-hydroxypropanal and NAD(+), for enhancing the production of 3-hydroxypropionic acid

3-Hydroxypropionic acid (3-HP) can be produced via the biological route involving two enzymatic reactions: dehydration of glycerol to 3-hydroxypropanal (3-HPA) and then oxidation to 3-HP. However, commercial production of 3-HP using recombinant microorganisms has been hampered with several problems, some of which are associated with the toxicity of 3-HPA and the efficiency of NAD(+) regeneration. We engineered a-ketoglutaric semialdehyde dehydrogenase (KGSADH) from Azospirillum brasilense for the second reaction to address these issues. The residues in the binding sites for the substrates, 3-HPA and NAD(+), were randomized, and the resulting libraries were screened for higher activity. Isolated KGSADH variants had significantly lower Km values for both the substrates. The enzymes also showed higher substrate specificities for aldehyde and NAD(+), less inhibition by NADH, and greater resistance to inactivation by 3-HPA than the wild-type enzyme. A recombinant Pseudomonas denitrificans strain with one of the engineered KGSADH variants exhibited less accumulation of 3-HPA, decreased levels of inactivation of the enzymes, and higher cell growth than that with the wild-type KGSADH. The flask culture of the P. denitrificans strain with the mutant KGSADH resulted in about 40% increase of 3-HP titer (53 mM) compared with that using the wild-type enzyme (37 mM)

Antioxidant effect of Morus nigra on Chagas disease progression

ABSTRACT Considering the widespread popular use of Morus nigra and the amount of scientific information on its antioxidant and anti-inflammatory activity, the effectiveness of this phytotherapeutic compound in the parasitemia progression during the acute phase of Chagas disease and its role in the development of the inflammatory process as well as its effects on the oxidative damage in the chronic phase of infection were evaluated. Thus, 96 male Swiss mice were randomly divided into eight groups, four groups were uninfected controls, and four groups were intraperitoneally infected with 5.0 x 104 blood trypomastigotes forms of T. cruzi QM2 strain. Four batches composed of one uninfected and one infected group were respectively treated with 70% alcohol solution and 25 μL, 50 μL and 75 μL of the phytotherapeutic compound. Levels of antioxidant elements (TBARS, FRAP, GSH and Sulfhydryl groups) were measured in plasma samples. The phytotherapeutic compound’s antioxidant activity was measured by polyphenol and total flavonoid quantification, DPPH, NO, and FRAP method. Our results showed that the vehicle influenced some of the results that may have physiological relevance in Chagas disease. However, an important action of M. nigra tincture was observed in the progression of Chagas disease, since our results demonstrated a reduction in parasitemia of treated groups when compared to controls, especially in the group receiving 25 µL. However, in the chronic phase, the 50-µL dosage presented a better activity on some antioxidant defenses and minimized the tissue inflammatory process. Results indicated an important action of M. nigra tincture on the Chagas disease progression

Antioxidant activity of polyphenolic plant extracts

[No abstract available

Assessment of antioxidant/anticarcinogenic activity of plant extracts by a combination of molecular methods

Cancer chemoprevention is considered to be a promising approach for cancer control, as it has been identified by both epidemiological and molecular studies that environmental factors are the major causes of cancer. Chemoprevention can be defined as the use of agents to prevent, inhibit or reverse the process of carcinogenesis. Several epidemiological studies have shown that fruits, vegetables and common beverages, as well as herbs and plants, are rich sources of chemopreventive compounds. In the present report, a battery of in vitro methods for the identification of chemopreventive agents are presented. These methods include: i) inhibition of bleomycin-induced mutations in Salmonella typhimurium TA102 cells, ii) inhibition of bleomycin-induced sister chromatid exchanges (SCEs) in human peripheral blood lymphocytes, iii) protection from mitomycin C-induced DNA strand breakage and iv) inhibition of topoisomerase I DNA relaxation. The first three methods are also used for the identification of agents which prevent reactive oxygen species (ROS)-mediated DNA damage

Plant phenolics protect from bleomycin-induced oxidative stress and mutagenicity in Salmonella typhimurium TA102

Antioxidants are deemed to be important against DNA damage and mutations induced by reactive oxygen species (ROS). An assay for the ability of plant phenolics to protect against mutations caused by bleomycin treatment in Salmonella typhimurium TA102 cells in concentrations tip to 20 muM was developed. Caffeic acid, gallic acid, protocatechuic acid, ferulic acid and rutin hydrate in final concentrations of 0.5 to 20 muM were tested for their ability to protect TA102 cells from mutations caused by oxidative stress from bleomycin. The cut-off concentration of 20 muM was used because as a limit it is biologically meaningful, higher concentrations being unrealistic in vivo. Caffeic acid was very potent at a concentration of 0.5 - 20 muM. The other four antioxidants were not effective rip to 20 muM. The above assay will be helpful to characterize antioxidant molecules

Influence of potent antioxidant leguminosae family plant extracts on growth and antioxidant defense system of Hep2 cancer cell line

Legumes are considered to be a very good source of polyphenolic compounds that may act as chemopreventive agents, especially by their antioxidant properties. However, many of the chemopreventive properties may depend on the concentrations of the phytochemical compounds because potent antioxidant polyphenolic compounds may have pro-oxidant properties and negatively affect cell growth and viability. Thus, the aim of the present study was to assess the possible effect of two potent antioxidant Greek Leguminosae family plant extracts on the growth of a specific cancer cell line and its antioxidant defense cell system. Aqueous extracts of aerial parts of Lathyrus laxiflorus and Phaseolus vulgaris plants were initially examined for their cytotoxicity on the Hep2 cancer cell line at concentrations that possess potent antioxidant properties (100, 400, and 800μg/mL). After a 24-hour incubation with the extracts, only L. laxiflorus plant extract exhibited the ability to inhibit the cell growth at 400 and 800μg/mL by 57% and 74%, respectively, whereas P. vulgaris extract had no effect on cell growth at any of the tested concentrations. Noncytotoxic concentrations, 100μg/mL L. laxiflorus and 800μg/mL P. vulgaris extract, were used for 2-, 12-, and 24-hour incubation of the cells. The influence of the extracts on the antioxidant defense system of the cells was assessed by measuring the total antioxidant capacity (TAC) of the cells, the catalase (CAT) activity, and the concentrations of reduced glutathione, the oxidized form of glutathione, and thiobarbituric-reactive substances (TBARS) in all times of incubation with the cells. From the results obtained, it seems that only L. laxiflorus extract induces oxidative stress in the cells by reducing TAC and CAT activity and by inducing TBARS, especially with 2 and 12 hours of incubation. P. vulgaris extract reduced only TAC at 2 hours of incubation, indicating also a mild induction of oxidative stress. These results imply that potent antioxidant extracts, beyond a critical concentration, may induce oxidative stress even with no apparent cytotoxicity in cells. © Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2010