Search results for "Natural products"
showing 10 items of 82 documents
Chemiczne markery miodów odmianowych
2011
Honey is a natural food product reach in variety of chemical compounds, which are responsible for its quality and aroma. Unifloral honeys are especially attractive for buyers and are quite frequently falsified. Thus, the assessment of their quality is indispensable. Today it relays on identification of the pollen and determination of honey physicochemical properties. In this paper the new methods for the assessment of honey quality are described. They relay on analysis and identification of volatile compounds typical for certain uniflolar honeys. These compounds are called markers. These could virtually all natural products with products of decomposition of phenylalanine, terpenes, flavonoi…
Synthetic studies on 1-azabicyclo[5.3.0]decane alkaloids
2018
The first chapter introduces the reader to the concept of natural product total synthesis and its importance to chemistry, other sciences, and society. The second chapter reviews the chemistry of natural products containing 1-azabicyclo[5.3.0]decane motifs. This bicyclic motif and the natural products related to it, have been a continuous source of synthetic inspiration over the last decades. The second chapter of the thesis reviews the strategies and tactics developed. The third chapter covers the author’s total synthesis of stemoamide, a 1-azabicyclo[5.3.0]decane motif containing alkaloid. Additionally, two diastereomers of stemoamide were synthesized, allowing their structural reassignme…
Synthetic Approaches to the Lamellarins—A Comprehensive Review
2014
The present review discusses the known synthetic routes to the lamellarin alkaloids published until 2014. It begins with syntheses of the structurally simpler type-II lamellarins and then focuses on the larger class of the 5,6-saturated and -unsaturated type-I lamellarins. The syntheses are grouped by the strategy employed for the assembly of the central pyrrole ring.
Antinociceptive Effects of Turkish Endemic Eryngium kotschyi Boiss. Roots by Bioactivity Guided Fractionation
2010
Eryngium species (Apiaceae) are well known plants in ethnobotanical culture throughout world and also in Turkey. They are used as antitussive, diuretic as well as for analgesic and antiinflammatory purposes in traditional medicine. This study aimed to evaluate the antinociceptive activity of endemic Eryngium kotschyi Boiss. root extracts by bioguided fractionation. The antinociceptive activity of the extracts/fractions/compound was studied in mice using acetic acid induced writhing test and and hot plate test. The methanolic extract was sequentially partitioned with hexane, dichloromethane and water saturated n-butanol. Among the fractions, the n-BuOH fraction showed the most significant re…
Four-Component Relativistic DFT Calculations of C-13 Chemical Shifts of Halogenated Natural Substances
2015
We have calculated the (13) C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental (13) C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density funct…
Targeting GSK3 and Associated Signaling Pathways Involved in Cancer
2020
Glycogen synthase kinase 3 (GSK-3) is a serine/threonine (S/T) protein kinase. Although GSK-3 originally was identified to have functions in regulation of glycogen synthase, it was subsequently determined to have roles in multiple normal biochemical processes as well as various disease conditions. GSK-3 is sometimes referred to as a moonlighting protein due to the multiple substrates and processes which it controls. Frequently, when GSK-3 phosphorylates proteins, they are targeted for degradation. GSK-3 is often considered a component of the PI3K/PTEN/AKT/GSK-3/mTORC1 pathway as GSK-3 is frequently phosphorylated by AKT which regulates its inactivation. AKT is often active in human cancer a…
Herbal Medications in Endodontics and Its Application—A Review of Literature
2022
Herbal products are gaining popularity in dental and medical practice nowadays due to their biocompatibility, higher antimicrobial activity, antioxidant and anti-inflammatory properties. Herbal medicine has experienced rapid growth in recent years due to its beneficial properties, ease of availability, and lack of side effects. As pathogenic bacteria become more resistant to antibiotics and chemotherapeutic agents, researchers are becoming more interested in alternative products and treatment choices for oral diseases. As a result, natural phytochemicals separated from plants and utilized in traditional medicine are suitable substitutes for synthetic chemicals. The aim of this review articl…
In Silico Analysis of Microarray-Based Gene Expression Profiles Predicts Tumor Cell Response to Withanolides
2012
Withania somnifera (L.) Dunal (Indian ginseng, winter cherry, Solanaceae) is widely used in traditional medicine. Roots are either chewed or used to prepare beverages (aqueous decocts). The major secondary metabolites of Withania somnifera are the withanolides, which are C-28-steroidal lactone triterpenoids. Withania somnifera extracts exert chemopreventive and anticancer activities in vitro and in vivo. The aims of the present in silico study were, firstly, to investigate whether tumor cells develop cross-resistance between standard anticancer drugs and withanolides and, secondly, to elucidate the molecular determinants of sensitivity and resistance of tumor cells towards withanolides. Usi…
A Catalyst Designed for the Enantioselective Construction of Methyl- and Alkyl-Substituted Tertiary Stereocenters
2015
Tertiary methyl-substituted stereocenters are present in numerous biologically active natural products. Reported herein is a catalytic enantioselective method for accessing these chiral building blocks using the Mukaiyama-Michael reaction between silyl ketene thioacetals and acrolein. To enable remote enantioface control on the nucleophile, a new iminium catalyst, optimized by three-parameter tuning and by identifying substituent effects on enantioselectivity, was designed. The catalytic process allows rapid access to chiral thioesters, amides, aldehydes, and ketones bearing an α-methyl stereocenter with excellent enantioselectivities, and allowed rapid access to the C4-C13 segment of (-)-b…