Biotransformation of newly synthesized coumarin derivatives by Candida albicans as potential antibacterial, antioxidant and cytotoxic agents

Antioxidant Activity of Coumarins and Their Metal Complexes

Ubiquitously present in plant life, coumarins, as a class of phenolic compounds, have multiple applications-in everyday life, in organic synthesis, in medicine and many others. Coumarins are well known for their broad spectrum of physiological effects. The specific structure of the coumarin scaffold involves a conjugated system with excellent charge and electron transport properties. The antioxidant activity of natural coumarins has been a subject of intense study for at least two decades. Significant research into the antioxidant behavior of natural/semi-synthetic coumarins and their complexes has been carried out and published in scientific literature. The authors of this review have noted that, during the past five years, research efforts seem to have been focused on the synthesis and examination of synthetic coumarin derivatives with the aim to produce potential drugs with enhanced, modified or entirely novel effects. As many pathologies are associated with oxidative stress, coumarin-based compounds could be excellent candidates for novel medicinal molecules. The present review aims to inform the reader on some prominent results from investigations into the antioxidant properties of novel coumarin compounds over the past five years.

Multi-Level Optimization and Strategies in Microbial Biotransformation of Nature Products

Continuously growing demand for natural products with pharmacological activities has promoted the development of microbial transformation techniques, thereby facilitating the efficient production of natural products and the mining of new active compounds. Furthermore, due to the shortcomings and defects of microbial transformation, it is an important scientific issue of social and economic value to improve and optimize microbial transformation technology in increasing the yield and activity of transformed products. In this review, the aspects regarding the optimization of fermentation and the cross-disciplinary strategy, leading to the microbial transformation of increased levels of the high-efficiency process from natural products of a plant or microbial origin, were discussed. Additionally, due to the increasing craving for targeted and efficient methods for detecting transformed metabolites, analytical methods based on multiomics were also discussed. Such strategies can be well exploited and applied to the production of more efficient and more natural products from microbial resources.

Biotransformation of the Phenolic Constituents from Licorice and Cytotoxicity Evaluation of Their Metabolites

Biotransformation of four bioactive phenolic constituents from licorice, namely licoisoflavanone (1), glycyrrhisoflavone (2), echinatin (3), and isobavachalcone (4), was performed by the selected fungal strain Aspergillus niger KCCM 60332, leading to the isolation of seventeen metabolites (5-21). Structures of the isolated compounds were determined on the basis of extensive spectroscopic methods, twelve of which (5-7, 10-17 and 19) have been previously undescribed. A series of reactions including hydroxylation, hydrogenation, epoxidation, hydrolysis, reduction, cyclization, and alkylation was observed in the biotransformation process. All compounds were tested for their cytotoxic activities against three different human cancer cell lines including A375P, MCF-7, and HT-29. Compounds 1 and 12 exhibited most considerable cytotoxic activities against all the cell lines investigated, while compounds 2 and 4 were moderately cytotoxic. These findings will contribute to expanding the chemical diversity of phenolic compounds, and compounds 1 and 12 may serve as leads for the development of potential cancer chemopreventive agents.

Crystal structure, chemical reactivity, kinetic and thermodynamic studies of new ligand derived from 4-hydroxycoumarin: Interaction with SARS-CoV-2

Currently, Covid-19 pandemic infects staggering number of people around the globe and causes a high rate of mortality. In order to fight this disease, a new coumarin derivative ligand (4-[(pyridin-3-ylmethyl) amino]-2H-chromen-2-one) (LTA) has been synthesized and characterized by single-crystal X-ray diffraction, NMR, ATR, UV-Visible and cyclic voltammetry. Chemical reactivity, kinetic and thermodynamic studies were investigated using DFT method. The possible binding mode between LTA and Main protease (Mpro) of SARS-CoV-2 and their reactivity were studied using molecular docking simulation. Single crystal X-ray diffraction showed that LTA crystallizes in a monoclinic system with P2 1  space group. The reactivity descriptors such as nucleophilic index confirm that LTA is more nucleophile, inducing complexation with binding species like biomolecules. The kinetic and thermodynamic parameters showed that the mechanism of crystal formation is moderately exothermic. The binding energy of the SARS-CoV-2/Mpro-LTA complex and the calculated inhibition constant using docking simulation showed that the active LTA molecule has the ability to inhibit SARS-CoV-2.

Overview on developed synthesis procedures of coumarin heterocycles

Considering highly valuable biological and pharmaceutical properties of coumarins, the synthesis of these heterocycles has been considered for many organic and pharmaceutical chemists. This review includes the recent research in synthesis methods of coumarin systems, investigating their biological properties and describing the literature reports for the period of 2016 to the middle of 2020. In this review, we have classified the contents based on co-groups of coumarin ring. These reported methods are carried out in the classical and non-classical conditions particularly under green condition such as using green solvent, catalyst and other procedures.