Artichoke and milk thistle pills and syrups as sources of phenolic compounds with antimicrobial activity

Abstract

a Dietary supplements based on hepatoprotective plants have been increasingly used in the prevention of liver injuries. In the present work, the aim was to study the phenolic profile and possibly relate it to the in vitro antimicrobial activity of two different formulations ( pills and syrups) of artichoke and milk thistle, the antioxidant and anti-hepatocellular carcinoma activities of which were previously reported by our research group. The phenolic profiles were obtained by HPLC-DAD-ESI/MS, and the antimicrobial activity evaluation was performed with the clinical isolates of multiresistant bacteria (Escherichia coli, extended spectrum β-lactamases (ESBL) producing Escherichia coli, Proteus mirabilis, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa). Artichoke syrup revealed the presence of vanillic acid and luteolin-7-O-glucoside while the pills possessed higher concentrations of 4-O-caffeoylquinic, 5-O-caffeoylquinic and 1,3-O-dicaffeoylquinic acids, this latest being able to inhibit the growth of MRSA.Regarding milk thistle formulations, the syrup presented isorhamnetin-O-deoxyhexoside-O-dihexoside, isorhamnetin-O-deoxyhexoside-O-hexoside and isorhamnetin-3-O-rutinoside as the major phenolic constituents whereas the pills were richer in taxifolin, silymarin derivatives and hydroxylated silibinin; the syrup revealed antimicrobial activity against all the studied bacteria with the exception of Proteus mirabilis whereas the pills revealed activity against ESBL producing Escherichia coli. Overall, all of the studied formulations revealed to be a good source of phenolic compounds, among which milk thistle syrup presented the highest variety and concentration of flavonoids, which is possibly related to its strongest antimicrobial activity.

Leaf parts from Greek artichoke genotypes as a good source of bioactive compounds and antioxidants

“…38 In contrast with leaf blades where flavonoid content was higher than phenolic acids in most of the genotypes (except for genotype SLB4), in petioles and midribs phenolic acids were the most abundant phenolic group in all the genotypes (64-76% of TPC), except for genotype SPM6 where flavonoids prevailed over the phenolic acids (65% of TPC) ( Reports regarding the phenolic compound composition of leaves show contradictory results. In particular, similarly to our study, Pandino et al 36 have detected significantly higher flavonoid content than phenolic acids in the leaves of clones of two Sicilian artichoke varieties, whereas Pistón et al, 11 Sihem et al, 40 and Pereira et al 34 have reported a higher content of phenolic acids than flavonoids in leaf extracts and dietary supplements, respectively. However, even in the study by Pandino et al, 36 significant variation between the studied clones was observed, a finding that is similar to the results of the present study.…”

A Comparative Study of Black and White Allium sativum L.: Nutritional Composition and Bioactive Properties

“…Antimicrobial activity screening was assessed according to Pereira et al [28] using microorganisms obtained from clinical isolates (Hospital Center of Trás-os-Montes and Alto Douro, Vila Real, Portugal).…”

Identification and quantification of caffeoylquinic acid derivatives in Cynara scolymus L. tablets and capsules

“…This species is widely used in the traditional medicine for the treatment of digestive disorders (Boughrara and Belgacen, 2015;Nogueira et al, 2016;Lima et al, 2016;Moradi et al, 2016). The scientific literature mainly reports its effects on liver diseases and often associates its effects to the presence of phenolic compounds such as caffeoylquinic acid derivatives (Pereira et al, 2016;Mohamed et al, 2016;Colak et al, 2016;Mocelin et al, 2016).…”