Phenolic Compounds from the Leaf Extract of Artichoke (Cynara scolymus L.) and Their Antimicrobial Activities

Abstract

A preliminary antimicrobial disk assay of chloroform, ethyl acetate, and n-butanol extracts of artichoke (Cynara scolymus L.) leaf extracts showed that the n-butanol fraction exhibited the most significant antimicrobial activities against seven bacteria species, four yeasts, and four molds. Eight phenolic compounds were isolated from the n-butanol soluble fraction of artichoke leaf extracts. On the basis of high-performance liquid chromatography/electrospray ionization mass spectrometry, tandem mass spectrometry, and nuclear magnetic resonance techniques, the structures of the isolated compounds were determined as the four caffeoylquinic acid derivatives, chlorogenic acid (1), cynarin (2), 3,5-di-O-caffeoylquinic acid (3), and 4,5-di-O-caffeoylquinic acid (4), and the four flavonoids, luteolin-7-rutinoside (5), cynaroside (6), apigenin-7-rutinoside (7), and apigenin-7-O--D-glucopyranoside (8), respectively. The isolated compounds were examined for their antimicrobial activities on the above microorganisms, indicating that all eight phenolic compounds showed activity against most of the tested organisms. Among them, chlorogenic acid, cynarin, luteolin-7-rutinoside, and cynaroside exhibited a relatively higher activity than other compounds; in addition, they were more effective against fungi than bacteria. The minimum inhibitory concentrations of these compounds were between 50 and 200 µg/mL.

Phytochemical and Antimicrobial Studies on Acacia saligna Leaves

“…Complete acid hydrolysis of (A 10 ) gave myricetin and glucose which were identified by CoPC using authentic markers. Both the 1 H NMR and 13 C NMR spectra confirmed the structure of (A 10 ) to be myricetin 3-O-glucoside, where the presence of β-glucopyranoside moiety in the compound of (A 10 We conclude from this study that, the chemical constituents of plant especially phenolic compounds, flavonoids and other compounds present in the plant may be involved in the observed antimicrobial effect of the plant's extract (18,19) .…”

Inhibitory activity of chlorogenic acid on enzymes involved in the fatty acid synthesis in animals and bacteria

“…Recently, EGCG and analogues were regarded as novel leading compounds of FAS inhibitors (14,15,35), therefore chlorogenic acid, as a mechanical analogue of EGCG, could offer some structural information for the future development of specific potent inhibitors of fatty acid synthesis in bacterial and human systems. Although chlorogenic acid has been reported to have anticancer and antibacterial effects (24,25), little is known about the molecular mechanisms through which chlorogenic acid inhibits carcinogenesis and the growth of bacteria. Based on the current results, these effects afforded by chlorogenic acid probably was, as least partially, related to the inhibition of FAS I in cancer cells and of those enzymes involved in the bacterial fatty acid synthesis, such as FabI (31) and FabG, because the inhibition of fatty acid synthesis could lead to the suppression of the growth of cancer cells and bacteria (9,35).…”

Phenolic Compounds and Antimicrobial Activity of Olive (Olea europaea L. Cv. Cobrançosa) Leaves

“…First, in a general way, the antimicrobial capacity of phenolic compounds is wellknown [18][19][20][21][22]. In addition, extracts may be more beneficial than isolated constituents, since a bioactive individual component can change its properties in the presence of other compounds present in the extracts [23].…”