Antioxidant and Anti-Inflammatory Activities of Six Flavonoids from Smilax glabra Roxb

Abstract

This study aimed to isolate, prepare and identify the main flavonoids from a standardized Smilax glabra flavonoids extract (SGF) using preparative HPLC, MS, 1H NMR and 13C NMR, determine the contents of these flavonoids using UPLC, then compare their pharmacological activities in vitro. We obtained six flavonoids from SGF: astilbin (18.10%), neoastilbin (11.04%), isoastilbin (5.03%), neoisoastilbin (4.09%), engeletin (2.58%) and (−)-epicatechin (1.77%). The antioxidant activity of six flavonoids were evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-Azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS+) radical scavenging activity and ferric reducing antioxidant power (FRAP). In addition, the anti-inflammatory activity of six flavonoids were evaluated by determining the production of cytokines (IL-1β, IL-6), nitric oxide (NO) using enzyme linked immunosorbent assay and the NF-κB p65 expression using Western blotting in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results showed that (−)-epicatechin, astilbin, neoastilbin, isoastilbin and neoisoastilbin had strong antioxidant activities, not only in DPPH and ABTS+ radicals scavenging capacities, but in FRAP system. Furthermore, all the six flavonoids could significantly inhibit the secretion of IL-1β, IL-6, NO (p < 0.01) and the protein expression of NF-κB p-p65 (p < 0.01) in LPS-stimulated RAW264.7 cells. This study preliminarily verified the antioxidant and anti-inflammatory activities of six flavonoids in S. glabra.

Effects of Apigenin on the Expression of LOX‐1, Bcl‐2, and Bax in Hyperlipidemia Rats

“…It has been evident by experimental and epidemiological studies that some plant polyphenols, especially flavonoids, may improve atherosclerosis associated with their wide range of antioxidant and anti‐inflammatory activities [21–23] . These findings suggest that certain plant polyphenols inhibit monocyte activation in vitro, which provides a theoretical basis for the application of phytochemicals as adjuvant therapy for hyperlipidemia to prevent cardiovascular events [24] …”

Prenylated Flavonoids with Potential Antimicrobial Activity: Synthesis, Biological Activity, and In Silico Study

“…As endogenous free radicals and human 5-lipoxygenase (5-hLOX) have been shown to have major roles in the pathogenesis of various health problems including inflammatory disorders [ 24 , 25 ], the compounds obtained here were tested as 5-hLOX inhibitors and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavengers. Since inflammation is related to bacterial-mediated infections, a dual anti-inflammatory, antibacterial agent with an improved safety profile is a goal for improved therapeutic benefits and better patient compliance [ 26 ].…”

Integrated Strategy From In Vitro, In Situ, In Vivo to In Silico for Predicting Active Constituents and Exploring Molecular Mechanisms of Tongfengding Capsule for Treating Gout by Inhibiting Inflammatory Responses

“…Besides, it has been shown that arachidonic acid can promote the production of ROS ( Shin and Kim 2009 ). Several components have been shown to play antioxidative roles by reducing the levels of ROS , such as astilbin (peak 103) ( Wang et al, 2018 ) and engeletin (peak 111) ( Zhao et al, 2020 ). Therefore, TDFC may partially exert its anti-gout effect by decreasing ROS formation.…”