Synthesis and Biological Activities of Thio-avarol Derivatives

Abstract

Eleven new thio-avarol derivatives (3-13) were synthesized. Their antimicrobial, brine shrimp lethality, and free-radical scavenging activities and acetylcholinesterase inhibition, together with 12 already reported semisynthetic thio-avarol derivatives (14-25), were evaluated. Structure-activity relationships among these thio derivatives were determined.

RETRACTED ARTICLE: Further in vitro biological activity evaluation of amino-, thio- and ester-derivatives of avarol

“…In addition, 3 0 -methylamino-avarone (5), 4 0 -phenylanino-avarone (6), 3 0 -benzylamine-avarone (7) and di-p-anysoil-benzoyl-avarol (10) were active at 1 mg (Table 1). Previous screening of AChE inhibitory activity indicated a moderate activity (1 mg) for all thioavarol derivatives with a carboxylic acid group in the molecule 6 . In comparison, the alkaloid galanthamine used clinically for the treatment of Alzheimer's disease inhibited the enzyme at 0.01 mg. On the basis of these results, the most active compounds (thioavarol derivatives 1-4) were further tested using Ellman's method ( Ester-avarolderivative 10 R 1 =R 2 = p-anisoyl-benzoyl- Figure 1.…”

“…Their effect on radical production and their redox chemistry have shown to be involved in biological activities of these compounds 5 . Recent findings indicate that some thioavarol derivatives exhibit acetylcholinesterase (AChE) inhibitory activity 6 . The abnormal activity of this enzyme is one factor responsible for Alzheimer's disease, the most common cause of senile dementia in later life 7 .…”

“…Thio-avarol derivatives represent the majority of compounds tested; however, some amino-and ester-avarol derivatives have been included in the aforementioned screening as well. The synthesis of all derivatives screened were available from literature 6,8,9 .…”

An environmentally benign and efficient synthesis of 2-thio-substituted benzothiazoles

“…2-Thio-substituted-1,3-benzothiazoles are significant scaffolds found in a large number of pharmaceutically active molecules [1][2][3][4][5][6]. These include Cathepsin-D inhibitor, potent heat shock protein-90 inhibitor, avarol-3′-thiobenzothiazole, 2-(thiocyanatomethylthio)-1,3-benzothiazole, and dual antagonist for the human CCR1 and CCR3 receptors [7,8].…”

A new depsidone of Lobaria pulmonaria with acetylcholinesterase inhibition activity

“…Therefore, they are based on an 11H-dibenzo[b,e] [1,4]dioxepin-11-one ring system 2 . As part of our continuing search on acetylcholinesterase (AChE) inhibitors 3 , a phytochemical investigation was conducted on a foliose lichen, Lobaria pulmonaria (L.) Hoffm. (Lobariaceae).…”