Anti-inflammatory and Cytotoxic Activities of Five Veronica Species.

Abstract

In the flora of Turkey, the genus Veronica L. (Scrophulariaceae) is represented by 79 species, 26 of which are endemic.1) In traditional Turkish medicines, some Veronica species are used as diuretics and in the healing of wound.2) In addition, several Veronica species are used to treat cancer, influenza, hemoptysis, leryngopharyngitis, hernia, cough and respiratory diseases and are also used as an expectorant and antiscorbutic. [3][4][5] Veronica species contain mainly iridoid glucosides, especially benzoic and cinnamic acid esters of catalpol, some phenylethanoid and flavonoid glycosides. [6][7][8][9][10][11] However, there is no report on the action mechanism of this genus.In our continuous research on Turkish medicinal plants, we have tried to evaluate the biological and pharmacological activity of Veronica species using a bioassay-guided fractionation method. In the present study, focusing on anti-inflammatory and cytotoxic activities, we screened five Veronica species. Suppressive effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophages were used to evaluate anti-inflammatory activity. Activated macrophages produce large amounts of important effector molecules that elicit inflammation. NO, a bioactive free radical, is one of these critical mediators which is produced by inducible NO synthase (iNOS) in inflammatory macrophages when stimulated with bacterial membrane components, LPS and cytokines.12) Although many studies have demonstrated that cytokine-induced NO production can damage parasites or tumor cells, NO is also linked to damage and death of normal cells.13) In fact, higher NO levels are demonstrated in patients with rheumatoid arthritis, systemic lupus erythematosous and inflammatory myositis, indicating that NO elicits and aggravates inflammation.14) The inflammatory effect of NO is mediated by its ability as a free radical and is associated with the increase in iNOS expression. Therefore, the suppressive effect on NO production in LPS stimulated macrophages is one of the useful indexes for evaluating antiinflammatory activity. The level of iNOS expression and the free radical scavenging ability mainly regulates NO level. In the present study, we assessed the anti-inflammatory effect of Veronica species by determining NO levels, iNOS expression and radical scavenging activity. Radical scavenging activity was evaluated using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging system. In this assay, antioxidants react with the stable free radical DPPH (which gives a strong absorption at 517 nm), resulting on the production of colorless 2,2-diphenyl-1-picryl hydrazine. 15)In addition, to find a novel activity of Veronica species, the cytotoxicity after treatment of tumor cells (KB and B16) with test fractions was determined using microculture tetrazolium assay. 16) MATERIALS AND METHODSReagents LPS (from Escherichia coli) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) were purchased from Sigma (St. Louis, MO, U.S.A.). Thioglycol...

Iridoid content and biological activities ofVeronica cuneifoliasubsp.cuneifoliaandV. cymbalaria

“…cuneifolia and V. cymbalaria hemoptysis, laryngopharyngitis, hernia, cough, and respiratory diseases, and are also used as an expectorant and antiscorbutic (Tomassini et al, 1995;Su et al, 1999;Grahamet et al, 2000). Earlier investigations performed on Veronica species resulted in the isolation mainly of iridoid glucosides, especially benzoic and cinnamic acid esters of catalpol, some phenylethanoid, and flavonoid glycosides (Chari et al, 1981;Taskova et al, 1998;Harput et al, 2002aHarput et al, , 2002bSaracoglu et al, 2002;Jensen et al, 2005). In this study, Veronica cuneifolia subsp.…”

“…The radical scavenging activity was determined by comparing the absorbance with that of blank (100%) containing only DPPH and solvent. All the analyses were done in 3 replicates (Hatano et al, 1989;Harput et al, 2002a;Kostadinova et al, 2007;Jensen et al, 2010).…”

“…MTT solution (10 µL of 5 mg/mL in PBS) was added and incubated for 4 h. Following the incubation, 100 µL of 10% SDS (sodium dodecyl sulfate) was added to each well to dissolve formed formazan crystals. The absorbance was measured at 577/655 nm using microplate reader (Mossman 1983;Harput et al, 2002a).…”

“…As a consequence of these results, the genus Veronica has been transferred to the Plantaginaceae Olmstead, 2005). Recently, it has been shown that the iridoid glucosides aucubin, catalpol, and 6-O-catalpol esters are characteristic for this genus and chemotaxonomic research concerning iridoid content of the genus have great importance for the reclassification of the close genera (Harput et al, 2002a(Harput et al, , 2002bTaskova et al, 2004;Jensen et al, 2005).…”

Phenylethanoid and Iridoid Glycosides from Veronica persica.

“…[11][12][13] Our previous research on this plant has demonstrated that the water soluble portion of MeOH extract has a suppressive effect on nitric oxide production in lipopolysaccharide-stimulated mouse peritoneal macrophages due to its free radical scavenging activity, and the chloroform soluble portion of MeOH extract shows cytotoxicity against KB and B16 cells. 14) Continuing our studies on bioactive constituents of Veronica species, we here examine V. persica and isolate a new phenylethanoid glycoside, termed persicoside (1) together with eleven known compounds: acteoside (2), 15) isoacteoside (3), 16) lavandulifolioside (4), 17) dulcitol (5), aucubin (6), 18) veronicoside (7), 19) amphicoside (8), 20) 6-O-veratroyl-catalpol (9), 21) catalposide (10), 20) verproside (11) 22) and verminoside (12). 23) This paper describes the isolation and the structure determination of the new phenylethanoid along with its free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.…”