20S proteasome inhibitory activity of flavonoids isolated from Spatholobus suberectus

Abstract

The promising biological role of the ubiquitin proteasome pathway (UPP) in cancer therapy has recently emerged. Inhibition of proteasome has been proposed as a new therapeutic target for treatment of cancer. Bioassay-guided fractionation of a MeOH extract of the stems of Spatholobus suberectus resulted in seven compounds, liquiritigenin (1), isoliquiritigenin (2), genistein (3), daidzein (4), medicarpin (5), 7-hydroxyflavanone (6) and formononetin (7), which were evaluated for the first time for their inhibitory effect on 20S proteasome. Among the isolated compounds, 2, 3 and 6 exhibited inhibitory activities on human 20S proteasome with IC(50) values of 4.88 ± 1.5, 9.26 ± 1.2 and 5.21 ± 1.5 µm, respectively.

A Diterpenoid Taxoquinone from Metasequoia Glyptostroboides with Pharmacological Potential.

“…The proteasome inhibition assay was done as follows; 3% sodium dodecyl sulfate was added to assay buffer to activate the 20S proteasome's chymotrypsinlike activity. 4 The assay buffer was added to the blank and sample plate, and a diluted solution of positive control was added to the inhibitor wells. The enriched proteasome fraction was diluted to a final assay concentration of 10 μg/mL using assay buffer.…”

“…Previously 20S proteasome inhibitory activities of various natural products including, coumarins, terpenes, flavonoids, phenols and saponins have been reported by others. 4,17,19 In addition, biological structure activity relationship also gives conformational evidences that presence of carbonyl group in taxoquinonemay influence the inhibitory activity against 20S proteasome.…”

“…1 Therefore, there has been a growing interest for generating broad-spectrum proteasome inhibitors of natural origin, especially from natural products for the preventive treatment of a variety of cancers to overcome chemotherapeutic side effects. 1,4 Influenza A (H1N1) is the subtype of influenza A virusthat is known as the most common cause of human influenza. Influenza, commonly known as 'flu' is a contagious respiratory disease induced by influenza viruses.…”

Secondary Metabolites Produced by an Endophytic Fungus Pestalotiopsis sydowiana and Their 20S Proteasome Inhibitory Activities

“…Among them, carfilzomib and marizomib are derived from natural substances produced by microorganisms. Many natural products have been evaluated as potential proteasome inhibitors: withaferin A from Acnistus arborescens; celastrol from Tripterygium wilfordii; gliotoxin from several fungi, including Aspergillus fumigatus, Trichoderma, and Penicillium; and ginsenoside Rd from Panax ginseng [9]. Despite a number of studies on proteasome inhibitors, there is still a need to discover new types of proteasome inhibitors with suitable pharmacological properties.…”

“…The extracts were subjected to a series of column chromatographic methods, which led to the isolation of 10 polyketides (1-10) (Figure 1). [9]. Despite a number of studies on proteasome inhibitors, there is still a need to discover new types of proteasome inhibitors with suitable pharmacological properties.…”