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Valorization of lignin based on its biological activities is always suffering the restriction from lignin heterogeneity, including wide molecular weight distributions and variable functional group contents. In this work, organosolv ethanol lignin (OEL) from corn stalk was divided into four fractions by multiple organic solvent successive extraction and the anti-tyrosinase activities of four obtained fractions were compared to evaluate the effect of lignin heterogeneity on the anti-tyrosinase activity. The characterization revealed that the successive extraction realized the fractionation of the heterogeneous OEL into four relatively homogeneous parts with gradually increasing molecular weight and decreasing phenolic OH content. The enzymatic inhibition study showed that the four fractions exhibited obviously different anti-tyrosinase activities and the dichloromethane fraction had the highest tyrosinase inhibition rate (75.12%, 0.5 mg/mL), whose value was comparable to the positive control p-hydroxybenzaldehyde. Besides, the relationships between the anti-tyrosinase activity and the lignin properties (purity, molecular weight and phenolic OH) were discussed to elucidate the possible formation mechanism of differences among the four lignin fractions in anti-tyrosinase activity. Consequently, these results suggest that lignin heterogeneity has a significant effect on the tyrosinase inhibition rate, and lignin fractionation is an effective way to screen lignin fractions with high anti-tyrosinase activity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Tuberculosis (TB) is a deadly infectious disease caused by the pathogen Mycobacterium tuberculosis (Mtb). Approximately, 1.8 and 1.3 million people are infected and die, from TB each year as estimated by the World Health Organization. Due to increase in the incidence of drug-resistant strains of Mtb, there is an urgent need to accelerate research which focuses on the development of new drugs with novel mechanism of action that can treat both drugsensitive and resistant TB infections., Objective: The purpose of this review study was to describe vitamins as drug target that can be explored to develop new anti tubercular drugs that can treat both drug-sensitive and resistant TB infections., Method: The methodological approaches include literature review which is performed in the databases like PubMed, Web of Science, Scopus, Springer and Science Direct, etc. On the basis of evaluation of literature sources, the review was complied., Results: This review study demonstrated that vitamins biosynthesis pathway could be used in the development of novel drug targets. Further sequencing of the Mtb genome facilitated research in target identification and validation that make possible the discovery of novel anti-TB agent with new mechanisms of action. Several compounds were identified, which target vitamin biosynthesis pathway /enzymes. Some other new targets were also identified and can be explored for the identification of novel structural moiety., Conclusion: Further exploration of these compounds which have been identified to target these vitamins related novel target pathways /molecules could led to the development of antitubercular drug which can be used in the treatment of drug sensitive and resistant TB., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

As a key enzyme for glycolysis, lactate dehydrogenase (LDH) remains as a topic of great interest in cancer study. Though a number of kinetic models have been applied to describe the dynamic behavior of LDH, few can reflect its actual mechanism, making it difficult to explain the observed substrate and competitor inhibitions at wide concentration ranges. A novel mechanistic kinetic model is developed based on the enzymatic processes and the interactive properties of LDH. Better kinetic simulation as well as new enzyme interactivity information and kinetic properties extracted from published articles via the novel model was presented. Case studies were presented to a comprehensive understanding of the effect of temperature, substrate, and inhibitor on LDH kinetic activities for promising application in cancer diagnosis, inhibitor evaluation, and adequate drug dosage prediction.

Potent and specific inhibitors of hyaluronidases, a group of enzymes preferentially catalysing the hydrolysis of hyaluronic acid, are not known so far. Such compounds could be useful as pharmacological tools for studying the physiological and pathophysiological role of both hyaluronan and hyaluronidases. The effects of sulphated and non-sulphated structurally different oligosaccharides on bovine testicular hyaluronidase, hyaluronidase from bee venom and hyaluronate lyase from Streptococcus agalactiae (hylB (4755)) were studied with the Morgan-Elson reaction. Several active compounds were identified within a series of sulphated beta-(1,4)-galacto-oligosaccharides. The determined IC (50) values of these sulphated oligosaccharides ranged from 4 microM to 630 microM for all hyaluronan-degrading enzymes. Sulphated oligosaccharides like verbascose, planteose and neomycin showed comparable inhibition on all hyaluronidases, thereby possessing 100 - 500 times the activity of the widely accepted hyaluronidase inhibitor apigenin.

A simple and novel gold nanoparticle (Au-NPs) based colorimetric method has been developed for efficient screening of class A β-lactamase (Bla) activity and inhibitors in vitroand in bacterial strains. [ABSTRACT FROM AUTHOR]