Quantitative Structure-Permittivity Relationship Study of a Series of Polymers

Dielectric constant is an important property which is widely utilized in many scientific fields and characterizes the degree of polarization of substances under the external electric field. In this work, a structure-property relationship of the dielectric constants (ε) for a diverse set of polymers was investigated. A transparent mechanistic model was developed with the application of a machine learning approach that combines genetic algorithm and multiple linear regression analysis, to obtain a mechanistically explainable and transparent model. Based on the evaluation conducted using various validation criteria, four- and eight-variable models were proposed. The best model showed a high predictive performance for training and test sets, with R2 values of 0.905 and 0.812, respectively. Obtained statistical performance results and selected descriptors in the best models were analyzed and discussed. With the validation procedures applied, the models were proven to have a good predictive ability and robustness for further applications in polymer permittivity prediction.

Bioactive Components and Biological Activities of Crocus sativus L. Byproducts: A Comprehensive Review

The production of saffron spice results in numerous byproducts, as only 15 g of spice can be produced from 1 kg of flowers, indicating that over 90% of the saffron flower material is eventually discarded as waste. In view of this, the paper reviews current knowledge on the natural active components in saffron byproducts and their biological activities, aiming to lay a theoretical and scientific foundation for the further utilization. Saffron byproducts contain a variety of phytochemical components, such as flavonoids, anthocyanins, carotenoids, phenolic acids, monoterpenoids, alkaloids, glycosides, and saponins. The activities of saffron byproducts and their mechanisms are also discussed in detail here.

Chemical constituents, anti-inflammatory and analgesic activities of iridoids preparation from Phlomoides labiosa bunge

This study reports the isolation of iridoids and cycloartane glycosides from the aerial parts of Phlomoides labiosa Bunge. Six compounds were isolated and the chemical structures were identified as phlorigidoside С (1), 8-O-acetylharpagide (2), shanzhiside methyl ester (3), cyclosiversioside A (4), cyclosiversioside E (5), and cyclosiversioside C (6). Compounds 4-6 are reported for the first time in this plant. In addition, anti-inflammatory and analgesic activities of iridoid fraction were studied. The sum of iridoids (SI) with intragastric administration is 5.2 and 52.5 times less toxic, than such market drugs as analgin and diclofenac sodium, respectively. In terms of the latitude of analgesic action (LD50/ED50), the SI exceeds analgin by 19.2 times and diclofenac sodium by 16 times. The anti-inflammatory and analgesic activities of the sum of iridoids were confirmed to be effective and nontoxic, and exceed known drugs diclofenac sodium and analgin (metamizole sodium).

Phytochemical constituents and biological activities of Dianthus helenae Vved., growing in Uzbekistan

In the present study, six known compounds were investigated that were isolated from the aerial parts of plant Dianthus helenae Vved. The structures of these compounds were identified as polypodine B (1), 2,3,20,22-diacetonide-20-hydroxyecdysone (2), 20-hydroxyecdysone (3), cyasterone (4), α-ecdysone (5) and 2-deoxy-α-ecdysone (6). Their structures were confirmed by NMR-, ESI-MS, and IR-spectroscopy. The compounds (5) and (6) are reported for the first time from this species. Furthermore, compounds (2) and (4) were isolated for the first time from the Caryophyllaceae family. In addition, all these phytoecdysteroids were investigated for a nootropic activity. Thus, the total phytoecdysteroids-containing preparation at a dose of 25 mg/kg increases two times the motor activity, an approximate reaction - four times and exploratory behavior - 1.4 times compared to control animals.

Iridoid glucosides and triterpene acids from Phlomis linearifolia, growing in Uzbekistan and its hepatoprotective activity

A number of iridoids and triterpene acids, such as pulchelloside, sesamoside, shanshiside methyl ester, barlerin, gypsogenin acid and acetate of gypsogenic acid were isolated from the aerial part of Phlomis linearifolia and their structures were confirmed by NMR, mass and IR spectroscopy. In addition, the hepatoprotective potential of iridoid fraction from P. linearifolia aerial parts was tested against CCl₄ induced fibrosis in rats. The iridoid fraction not only prevented the manifestation of the hepatotoxic effect of CCl₄, but rather quickly eliminated the effects of developing intoxication. The hepatoprotective activity of the SI was confirmed to be effective and exceeds knows drug carsil.Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1677650.