Correlation between polyphenol content and anti-inflammatory activity ofVerbascum phlomoides(mullein)

Abstract

Context: Verbascum phlomoides L. (Scrophulariaceae) (mullein) used in the European folk medicine due to its anti-inflammatory and soothing action on the respiratory tract is thoroughly documented in handbooks and scientific literature. Nevertheless, information regarding the influence of the polyphenol content on pharmacological activity is scarce. Objective: This study explored the antioxidant and anti-inflammatory potential of V. phlomoides polyphenol-rich extract. Materials and methods: Dried mullein flowers (200 g) were subjected to water extraction (60 C, 2 h, herb/solvent ratio ¼ 1/10 m/v) and further to n-butanol partition. Total phenolics were spectrophotometrically determined and specific compounds were evaluated by HPLC. The antioxidant activity was assessed by the 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) assay. The anti-inflammatory potential of the extract (50-200 mg/mL) was evaluated in vitro by ELISA measurement of ICAM-1 expression in TNF-a-stimulated endothelial cells and in vivo by the rat paw edema assay. Results: The mullein extract contained 4.18% total polyphenols expressed as gallic acid. The main components identified by HPLC were: rosmarinic acid (14.93 mg/g), caffeic acid (39.96 mg/g), ferulic acid (29.61 mg/g) and quercetin (17.29 mg/g). Acteoside was not detected; aucubin was detected in traces (0.028 mg/g). Depending on concentration, the extract exerted scavenging activity on DPPH radical (EC 50 7.09 mg/mL), significantly inhibited TNF-a-induced ICAM-1 expression by 55-58.8% on human umbilical vein endothelial cells at 100 and 200 mg/mL, but failed to reduce egg-white-induced rat paw edema. Discussion and conclusion: Mullein polyphenols play an important role in exerting the antioxidant effect but have a weak influence on anti-inflammatory activity that is correlated, probably, to a higher content of iridoids and phenylethanoids.

HPLC‐DAD‐ESI‐Q‐TOF‐MS/MS profiling of Verbascum ovalifolium Donn ex Sims and evaluation of its antioxidant and cytogenotoxic activities

“…Its concentration varied between 13.20 mg/g in AQE and 18.03 mg/g in BE. As compared to the report of Grigore et al . that found aucubin only in traces (0.028 mg/g) in the n ‐butanol fraction of the aqueous extract of V. phlomoides , the amounts of aucubin exhibited in V. ovalifolium extracts are remarkably higher.…”

CD39/NTPDase-1 expression and activity in human umbilical vein endothelial cells are differentially regulated by leaf extracts from Rubus caesius and Rubus idaeus

“…The results of this study demonstrate that dewberry and raspberry leaf extracts may enhance ICAM-1 expression in non-stimulated and TNF-α-stimulated HUVEC. Most studies concerning the effect of polyphenols on HUVEC activation have shown that these compounds are able to suppress the expression of ICAM-1 when it has been elevated by inflammatory cytokines or pathological conditions [8,48]. Interestingly, Mochizuki et al have demonstrated that the influence of quercetin derivatives on enhanced ICAM-1 expression in TNF-α-stimulated HACEs may depend on their specific chemical structures.…”

UPLC-Q-TOF/MS-based screening and identification of two major bioactive components and their metabolites in normal and CKD rat plasma, urine and feces after oral administration of Rehmannia glutinosa Libosch extract

“…In the last decade, herbal medicines and their derived products were widely used to treat diseases in many countries. Rehmannia glutinosa Libosch which belongs to the family Scrophulariaceae has been widely used to nourish the Yin deficiency of liver, kidney accumulation of leukocytes in the glomeruli [10,11]. Both catalpol and acteoside are the chemical components for controlling the quality of R. glutinosa in the Chinese Pharmacopoeia [12].…”