Amounts Of Phenylpropanoids Research Articles

R2R3-MYB transcription factors, StmiR858 and sucrose mediate potato flavonol biosynthesis

Flavonols and other phenylpropanoids protect plants from biotic and abiotic stress and are dietarily desirable because of their health-promoting properties. The ability to develop new potatoes (Solanum tuberosum) with optimal types and amounts of phenylpropanoids is limited by lack of knowledge about the regulatory mechanisms. Exogenous sucrose increased flavonols, whereas overexpression of the MYB StAN1 induced sucrolytic gene expression. Heterologous StAN1 protein bound promoter fragments from sucrolytic genes (SUSY1 and INV1). Two additional MYBs and one microRNA were identified that regulated potato flavonols. Overexpression analysis showed MYB12A and C increased amounts of flavonols and other phenylpropanoids. Endogenous flavonol amounts in light-exposed organs were much higher those in the dark. Expression levels of StMYB12A and C were high in flowers but low in tubers. Transient overexpression of miR858 altered potato flavonol metabolism. Endogenous StmiR858 expression was much lower in flowers than leaves and correlated with flavonol amounts in these organs. Collectively, these findings support the hypothesis that sucrose, MYBs, and miRNA control potato phenylpropanoid metabolism in a finely tuned manner that includes a feedback loop between sucrose and StAN1. These findings will aid in the development of potatoes with phenylpropanoid profiles optimized for crop performance and human health.

METHOD FOR QUANTIFYING THE AMOUNT OF PHENYLPROPANOIDS IN STEVIA RAW MATERIALS

Dried stevia leaves (Stevia rebaudiana Bertoni) were used as objects of research. Four samples of stevia raw materials of different origin were studied: No. 1 (Russia, Penza region), No. 2 (Russia, Republic of Crimea), No. 3 (Paraguay), No. 4 (India). The purpose of this work is to develop a method for quantifying the amount of phenylpropanoids in stevia leaves.
 Quantitative determination of the amount of phenylpropanoids in stevia leaves by direct spectrophotometry was carried out. Thin-layer chromatography was used to confirm the presence of phenylpropanoids in stevia leaves. The presence of phenylpropanoids in stevia leaf extracts was confirmed by direct spectrophotometry, the analytical maxima of the compounds studied were determined – 290 and 330 nm. The optimal conditions of extraction of phenylpropanoids from raw materials of this plant (extractant – ethyl alcohol 70%; ratio "raw material–extractant" – 1 : 100; extraction time – 45 min; the degree of grinding of raw materials – 1.0 mm). It was determined that the error of a single determination of the content of phenylpropanoids in stevia leaves with a confidence probability of 95% is ±0.44%. It was found that the content of phenylpropanoids in stevia varies in the range of 6.73–10.51%.

Chemical Diversity and Biological Activities of Essential Oils from Licaria, Nectrandra and Ocotea Species (Lauraceae) with Occurrence in Brazilian Biomes.

Lauraceae species are known as excellent essential oil (EO) producers, and their taxa are distributed throughout the territory of Brazil. This study presents a systematic review of chemical composition, seasonal studies, occurrence of chemical profiles, and biological activities to EOs of species of Licaria, Nectandra, and Ocotea genera collected in different Brazilian biomes. Based on our survey, 39 species were studied, with a total of 86 oils extracted from seeds, leaves, stem barks, and twigs. The most representative geographic area in specimens was the Atlantic Forest (14 spp., 30 samples) followed by the Amazon (13 spp., 30 samples), Cerrado (6 spp., 14 samples), Pampa (4 spp., 10 samples), and Caatinga (2 spp., 2 samples) forests. The majority of compound classes identified in the oils were sesquiterpene hydrocarbons and oxygenated sesquiterpenoids. Among them, β-caryophyllene, germacrene D, bicyclogermacrene, caryophyllene oxide, α-bisabolol, and bicyclogermacrenal were the main constituents. Additionally, large amounts of phenylpropanoids and monoterpenes such as safrole, 6-methoxyelemicin, apiole, limonene, α-pinene, β-pinene, 1,8-cineole, and camphor were reported. Nectandra megatopomica showed considerable variation with the occurrence of fourteen chemical profiles according to seasonality and collection site. Several biological activities have been attributed to these oils, especially cytotoxic, antibacterial, antioxidant and antifungal potential, among other pharmacological applications.

Chemical Composition and Antimicrobial Activity of Essential Oils from Different Parts of Daucus littoralis Smith subsp. hyrcanicus Rech. f.

Daucus littoralis Smith subsp. hyrcanicus Rech. f (Apiaceae) is an endemic species in north of Iran. The chemical composition of the essential oils obtained from different parts (leaves and stems, roots, flowers and fruits) of this plant have been investigated by GC and GC-MS for the first time. The essential oils of all parts were characterized by high amounts of sesquiterpene hydrocarbons (62 to 67 %) especially germaceren D (22 to 36 % in leaves, stems, flowers and roots) and acorenone B (19.7 to 57.5 % in all parts). So this can be considered as a remarkable difference between this species and other Daucus species. The high amounts of phenylpropanoids (8 to 30.3 %) were also found in all parts. Fruits oil was characterized by higher amounts of phenylpropanoids(30.3 %) while other parts were consisted of 8 to 10 % of these compounds. Myristicin was identified in leaves/stems, roots and fruits oil of this plant as one of the major components (8.6 %, 9.5 % and 15.2 % respectively). Elimicin (15.1 %) was identified as a major component in fruits but in lower amount (0.4 to 3.6 %) in other parts. All the essential oils have antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans with MIC value ranged of 20-40 μl/ml.

Composition, miticidal activity and growth regulation effect on radish seeds of extracts from Melaleuca species

Abstract The leaf oil components of six Melaleuca species were analyzed. M. symphyocarpa had a higher content of 1,8-cineole and M. bracteata contained large amounts of phenyl propanoids, while the other species had oils which contained complex mixture of mono- and sesquiterpenes. The leaf oil of M. bracteata exhibited the strongest miticidal activity against European house-dust mites (Dermatophagoides pteronyssinus) . It also had the strongest germination and growth-inhibition activity against radish seeds.

Modified-atmosphere packaging of minimally processed "Lollo Rosso" ( Lactuca sativa )

The effect of modified-atmosphere packaging (MAP) on the amount of soluble phenolics in, and the visual appearance of, white, green and red tissues of minimally processed “Lollo Rosso” lettuce were evaluated. Minimal processing induced a two-fold increase in the amount of soluble phenylpropanoids in the midribs during storage in air at 5°C. When the lettuce was stored in the presence of 2–3% O2 and 12–14% CO2, this increase was not induced and no browning was observed. A particularly marked decrease in the amount of phenylpropanoids was observed in MAP-stored green and red tissues. The concentrations of flavonoids and anthocyanins did not change much in midribs and green tissues, while they were significantly degraded in red tissues under MAP conditions. MAP storage proved useful in the prevention of browning, the main cause of quality loss in minimally processed “Lollo Rosso” lettuce. However, MAP storage was not so beneficial for the preservation of the quality of red tissues and, in fact, their overall visual quality, texture, aroma and macroscopic breakdown under MAP conditions were worse than those of air-stored tissues.