Neoastilbin

Antioxidant and Anti-Inflammatory Activities of Phenolic-Enriched Extracts of Smilax glabra.[Pubmed: 25477999 ]

Evid Based Complement Alternat Med. 2014;2014:910438.

Smilax glabra Roxb. has been used for a long time as both food and folk medicine.
METHODS AND RESULTS:
In the present study, phenolic-enriched extract of S. glabra (PEESG) was extracted with 70% ethanol and purified by HP-20 column chromatography. Its antioxidant and anti-inflammatory activities were evaluated by radical scavenging assay, reducing power determination, and lipopolysaccharide (LPS)-induced RAW264.7 cells assays, respectively. PEESG exhibited obviously scavenging capacity for DPPH and ABTS radicals, as well as significant reducing power for ferric ion. Particularly, PEESG (12.5–50 μg/mL) showed a significantly higher efficiency for scavenging ABTS than that of ascorbic acid and no significant difference with ascorbic acid for DPPH scavenging. PEESG also possessed a significant suppression effect on proinflammatory mediators production, such as nitric oxide (NO), tumor necrosis factor- α (TNF- α ), and interleukin-6 (IL-6), in LPS-induced RAW264.7 cells. In addition, the main ingredients of PEESG were identified using ultrahigh pressure liquid chromatography coupled to electrospray mass spectrometry (U-HPLC-ESI-MS). Seventeen components, including 5-O-caffeoylshikimic acid, Neoastilbin, astilbin, neoisoastilbin, isoastilbin, engetin and isoengeletin were identified.
CONCLUSIONS:
These findings strongly suggest the potential of PEESG as a natural antioxidant and anti-inflammatory agent.

Inhibition of aldose reductase by dihydroflavonols in Engelhardtia chrysolepis and effects on other enzymes.[Pubmed: 8698090 ]

Experientia. 1996 Jun 15;52(6):564-7.

METHODS AND RESULTS:
Astilbin and Neoastilbin, dihydroflavonol rhamnosides from Engelhardtia chrysolepis, showed potent inhibition of lens aldose reductase.
CONCLUSIONS:
Kinetic analysis showed astilbin exhibited uncompetitive inhibition against both dl-glyceraldehyde and NADPH. These taxifolin glycosides were selective inhibitors of aldose reductase with no inhibition of NADH oxidase.

Zhongguo Zhong Yao Za Zhi. 2004 Sep;29(9):867-70.

Studies on dihydroflavonol glycosides from rhizome of Smilax glabra.[Pubmed: 15575206]

To investigate the chemical constituents from the rhizomes of Smilax glabra.
METHODS AND RESULTS:
The compounds were isolated by column chromatography with silica gel, Diaion HP-20 and ODS as packing materials, and HPLC. Their structures were determined on the basis of their spectral evidence. 5 dihydro-flavonol glycosides were identified as: astilbin (1), Neoastilbin (2), isoastilbin (3), neoisoastilbin (4), (2R, 3R)-taxifolin-3'-O-beta-D-pyranglucoside (5).
CONCLUSIONS:
Compounds 2, 4, 5 were isolated from this plant for the first time.