Background: Female age-related estrogen deficiency increases the risk of osteoporosis, which can be effectively treated with the use of hormone replacement therapy. However, hormone replacement therapy is demonstrated to increase cancer risk. Bioavailable isoflavones with selective estrogen receptor affinity show potential to prevent and treat osteoporosis while minimizing or eliminating carcinogenic side effects.

To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. ’Batavia’ (green) and cv. ‘Lollo Rossa’ (red)] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T) lamps yielding 90 (±10) µmol m-2 s-1 for up to 20 hr, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED) light treatments were Control (no blue addition), 1B 06-08 (Blue light at 45 µmol m-2 s-1 from 06:00 to 08:00), 1B 21-08 (Blue light at 45 µmol m-2 s-1 from 21:00 to 08:00), 2B 17-19 (Blue at 80 µmol m-2 s-1 from 17:00 to 19:00), and (1B 17-19) Blue at 45 µmol m-2 s-1from 17:00 to 19:00. Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent.

Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection.

The structure of fucoidan isolated from Laminaria hyperborea was elucidated and chemically tailored in order to obtain a clear structure-function relationship on bioactive properties with a minimal amount of variations among the tested molecules. Analysis revealed a sugar composition of 97.8% fucose and 2.2% galactose. Analysis of the glycosidic linkages showed (1→3)-α-L-fuco-pyranose (31.9%) to be the dominant residue, followed by 1→2 linked (13.2%) and 1→4 linked (7.7%) fuco-pyranose as well as high degree of branching (22.4%). ICP-MS revealed a sulfate content of 53.8% (degree of sulfation (DS) = 1.7). Raman spectroscopy determined SO₄ located axial at 4C and equatorial at 2C as well as an absence of acetylation. SEC-MALS analysis determined a high molecular weight (Mw = 469 kDa), suggesting a highly flexible main chain with short side chains. Both chemical shifts of the fucoidan, proton and carbon was assigned by NMR and revealed a highly heterogeneous structure in terms of glycosidic linkages. Bioactivity was assessed using a lepirudin-based whole blood model. The immediate responses by coagulation and complement cascades were measured by prothrombine factor 1 and 2 (PTF1.2) and the terminal complement complex (TCC). Cytokines involved in inflammation were detected in a 27-plex cytokine assay. Fucoidan with a high Mw and DS inhibited coagulation, complement and the cytokines PDGF-BB, RANTES, and IP-10, while activating MCP-1. These effects were obtained at the concentration of 1000 ug/mL and partly at 100 ug/mL. In low concentrations (10 ug/mL), a coagulation stimulating effect of highly sulfated fucoidans (DS = 1.7, Mw = 469 kDa or 20.3) was obtained. These data point to a multitude of effects linked to the sulfation degree that needs further mechanistic exploration.