Secondary Metabolites: Alkaloids and Flavonoids in Medicinal Plants

Secondary metabolites (SMs) are natural compounds produced mainly by bacteria, fungi, and plants. They are low molecular weight compounds that have a wide range of chemical structures and biological functions. Secondary metabolites are so named because, unlike primary metabolites such as lipids, amino acids, carbohydrates, and nucleic acids, their synthesis is not required for the organism’s development and reproduction. Today, the production of secondary metabolites is an important area of research for organic chemists, molecular biologists, and bioinformaticians. In this research, two types of secondary metabolites produced by plants, such as alkaloids and flavonoids, were studied and information was collected on the types of compounds, structures, biological activities, and commercial applications of these two types of secondary metabolites

Highly-efficient capture of chromium (VI) ions on electrospun polyacrylonitrile/diaminoglyoxime nanofiber: thermal stability, decomposition kinetics and tensile strength

In this study, a new polyacrylonitrile/diaminoglyoxime-based nanofiber was developed using electrospinning thanks to their outstanding chemical-mechanical properties used as effective adsorbents for the Cr(VI) removal without any secondary pollution. However, thermal stability and degradation of these nonpolymeric-mats could limit their application. The electrospun polyacrylonitrile with different percentages of diaminoglyoxime (%) nanofibers have their average diameters between 70 and 85 nm. The DSC technique was used to characterize the thermal stability of the manufactured polyacrylonitrile/diaminoglyoxime nanofiber. Decomposition kinetic parameters of the mats via the non-isothermal approaches and thermodynamic parameters (ΔG#, ΔH# and ΔS#) were determined. Polyacrylonitrile/diaminoglyoxime(30%) reached maximum adsorption capacity of 348.7 mg g−1 for Cr(VI) ions. After conducting the adsorption–desorption test for 20 times, polyacrylonitrile/diaminoglyoxime(30%) nanofiber exhibited excellent regeneration and stable desorption efficiency of over 73%. Compared with complicated industrial-sized chemicals for adsorbing Cr(VI), the nanofiber mat proposed herein is a simple one-step electrospinning process, which is extremely successful for industrial applications, cheap and without harmful by-products. Polyacrylonitrile/diaminoglyoxime (30%) was proposed as an appropriate material to adsorb Cr(VI) ions