Evaluation of Antioxidant,Anti-Inflammatory and Antityrosinase Potential of Extracts from Different Aerial Parts of Rhanterium suaveolens from Tunisia

The genus Rhanterium (Asteraceae) is a widely distributed medicinal plant throughout western North Africa and some Rhanterium species are used in folk medicine. The aim of research was to investigate methanolic extracts from different parts (flowers, leaves, and stems) of Tunisian Rhanterium suaveolens as potential sources of bioactive products useful for healthy purposes. In particular, were analyzed the phenolic composition of these extracts and their antioxidant, anti-inflammatory, and anti-tyrosinase properties. The phytochemical analyses were performed using standard colorimetric procedures, HPLC-DAD and HPLC-DAD-ESI-MS. Then, several in vitro cell-free assays have been used to estimate the antioxidant/free radical scavenging capability of the extracts. Moreover, in vitro, and in vivo anti-melanogenesis activities of these extracts were tested, respectively, with the tyrosinase inhibition assay and the Zebrafish embryo model. Finally, the anti-inflammatory potential of these extracts in an in vitro model of acute intestinal inflammation in differentiated Caco-2 cells was evaluated. The R. suaveolens extracts under study appeared particularly rich in flavonols and hydroxycinnamic acids and all extracts appeared endowed with good antioxidant/free radical scavenging properties, being the flower extracts slightly more active than the others. Moreover, R. suaveolens flowers extract was able to inhibit in vitro tyrosinase activity and exhibited bleaching effects on the pigmentation of zebrafish embryos. Furthermore, all extracts showed good anti-inflammatory activity in intestinal epithelial cells as demonstrated by the inhibition of TNF-α-induced gene expression of IL-6 and IL-8. R. suaveolens aerial parts may be considered as a potential source of whitening agents, as well as of agents for the treatment of disorders related to oxidative stress and inflammation.     

Protein crosslinking: Uses in chemistry,biology and biotechnology

Abstract

Protein crosslinking is a part of many biological processes and is also carried out in vitro under several controllable conditions with the help of any of the commercially available bifunctional reagents. Many biotechnological applications utilize stable and/or reusable crosslinked enzymes such as soluble intramolecularly crosslinked enzymes; soluble bioconjugates of enzymes with other enzymes/proteins or polymers; chemically aggregated enzymes, chemically crosslinked enzyme aggregates and crosslinked enzyme crystals. The review after indicating how protein crosslinking is at the heart of such diverse processes/technology concludes with discussion of few applications which are currently drawing considerable attention.     

Affinity directed assembly of multilayers of pectinase

Numerous approaches to creating protein multilayers have been described for a variety of applications. In this work, the affinity of the enzyme pectinase towards a natural polysaccharide alginate has been exploited to create affinity directed enzyme multilayers on alginate beads. The biocatalyst has been characterized in terms of catalytic efficiency and kinetic parameters. Atomic force microscopy provided a good insight into multilayer formation at the molecular level. It was seen that enzyme layering was not uniform all over the bead. Thus, achieving high catalytic efficiency was an ‘average performance’ of the enzyme molecule, which was part of different layers. The results show that it is possible to create layered biocatalyst designs without using expensive lectins/antibodies for constructing affinity layers.