1,7-Dihydroxy-2,3-dimethoxyxanthone

J Enzyme Inhib Med Chem. 2012 Feb;27(1):1-4.

Chemical constituents of Polygala tenuifolia roots and their inhibitory activity on lipopolysaccharide-induced nitric oxide production in BV2 microglia.[Pubmed: 21740104 ]

A methanolic extract of the roots of Polygala tenuifolia (Polygalaceae) significantly attenuated nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated BV2 microglia cells.
METHODS AND RESULTS:
Five xanthones, 1-hydroxy-7-methoxyxanthone (1), 3,6-dihydroxy-1,2,7-trimethoxyxanthone (2), 1,3,6-trihydroxy-2,7-dimethoxyxanthone (3), 1,7-Dihydroxy-2,3-dimethoxyxanthone (4) and 1,7-dihydroxy-3-methoxyxanthone (5), and five phenylpropanoids, 4-hydroxy-3-methoxypropiophenone (6), methyl 4-hydroxy-3-methoxycinnamic acid (7), 3,4,5-trimethoxycinnamic acid (8), 4-methoxycinnamic acid (9) and β-d-(3-O-sinapoyl) fructofuranosyl-α-d-(6-O-sinapoyl)glucopyranoside (10), were isolated from CHCl(3) fraction using bioactivity-guided fractionation.
CONCLUSIONS:
Among these compounds, compounds 1, 2, 4, 5 and 7 showed significant inhibitory effects on LPS-induced NO production in BV2 microglia cells at the concentration ranging from 10.0 to 100.0 μM.

J Pharm Pharmacol. 2013 May;65(5):767-76.

Role of gastric mucus secretion, oxinitrergic system and sulfhydryl groups on the gastroprotection elicited by Polygala cyparissias (Polygalaceae) in mice.[Pubmed: 23600395]

This study has aimed to assess the mechanisms of action for the gastroprotective effect of the acetone extract (PCAE) and methanol fraction (PCMF) of Polygala cyparissias, as well as to evaluate the activity of 1,3,6,8-tetrahydroxy-2,7-dimethoxyxanthone (1), 1,7-Dihydroxy-2,3-dimethoxyxanthone (2) and astragalin (3).
METHODS AND RESULTS:
Gastric secretion and mucus content were determined by pylorus ligation in mice. Nitric oxide (NO) and sulfhydryl group participation were observed by the pretreatment of mice with L-NAME or NEM. Acute ulcer was induced by ethanol/HCl and chronic ulcer by acetic acid. Anti-Helicobacter pylori activity was evaluated by the agar solid dilution assay. KEY FINDINGS: Neither PCAE nor PCMF had the ability to reduce H(+) concentration. However, both of them enhanced mucus secretion. PCAE demonstrated its gastroprotection in a NO-dependent manner, while PCMF exerted the activity depending on the sulfhydryl group. In chronic ulcer, the curative ratios for the PCAE and PCMF were 67.5 and 58.4%, respectively. No effect over H. pylori was detected. Compounds 1, 2 and 3 were able to reduce lesions in the order of 79.6, 73.8 and 67.6%, respectively.
CONCLUSIONS:
The data suggested that PCAE and PCMF displayed antiulcer activity due to different mechanisms and with the participation of phenolic compounds obtained from the plant.

Inflamm Res. 1999 Apr;48(4):218-23.

In vitro effect of the extract and the 1,7-dihydroxy-2,3-dimethoxy xanthone from Polygala cyparissias on the contractions induced by inflammatory mediators and ovalbumin in normal and actively sensitised trachea from guinea pig.[Pubmed: 10344473]

METHODS AND RESULTS:
The hydroalcoholic extract of P. cyparissias (0.125 to 1 mg/ml), incubated with the guinea-pig trachea for 20 min, had no effect on the resting tone of the preparations, but caused a concentration-dependent, reversible and non competitive inhibition of contractions induced by acetylcholine, histamine, compound 48/80, bradykinin, substance P, prostaglandin E2 and the stable analogue of thromboxane A2 mimetic U 46619. The calculated mean IC50 values for the hydroalcoholic extract were: 0.37, 0.51, 0.06, 0.32, 0.48, 0.3 and 0.17 mg/ml, respectively. Also, the extract of P. cyparissias (0.125 to 0.5 mg/ml) antagonised, in a graded manner (IC50 of 0.46 mg/ml) ovalbumin-induced contractions in guinea-pig trachea obtained from animals which had been actively sensitised to this antigen. Pre-incubation of the preparations with the purifed xanthone isolated from P. cyparssias (2.5 to 80 microg/ml; 10.0 to 310.0 microM) caused significant and concentration-dependent, reversible and noncompetitive inhibition of the contractile responses elicited by acetylcholine, histamine, bradykinin, substance P, U 46619 and prostaglandin E2. The calculated mean IC50 values for these effects were: 132.0, 73.0, 9.2, 32.0, 110.6 and 66.0 microM, respectively. At very high concentrations (I55.0-620.0 microM) the xanthone also antagonised contraction induced by KCl in guinea-pig trachea (IC50 of 190.0 microM).
CONCLUSIONS:
Taken together these and our previous in vivo results are consistent with the view that the active principles present in P. cyparissias, including the 1,7-Dihydroxy-2,3-dimethoxyxanthone, antagonise, in a non competitive but, reversible manner the contractions induced by chemical inflammatory mediators in the guinea pig trachea in vitro. Thus, these results might explain at least in part, the medicinal use of this plant in the management of inflammation, asthma and allergy.

Z Naturforsch C. 2004 May-Jun;59(5-6):335-8.

Xanthones from Polygala alpestris (Rchb.).[Pubmed: 18998397]

METHODS AND RESULTS:
Bioactivity-guided fractionation of Polygala alpestris L. (Rchb.) extracts led to the identification of two new xanthones, 1,3,7-trihydroxy-2,6-dimethoxyxanthone (1) and 2,3-methylenedioxy-4,7-dihydroxyxanthone (2). In addition five known compounds 3,4-dimethoxy-1,7-dihydroxyxanthone (3), 1,3-dihydroxy-7-methoxyxanthone (4), 1,7-Dihydroxy-2,3-dimethoxyxanthone (5), 3',6-O-disinapoyl sucrose (6) and 3',5'-dimethoxybiphenyl-4-olo (7) were isolated.
CONCLUSIONS:
The structures of the isolated compounds were established by means of high resolution mass spectrometry, mono- and bi-dimensional NMR spectroscopy. All isolated compounds were tested for cytotoxic activity against three tumor cell lines (LoVo, HL-60, K 562).