Antimicrobial and Antiviral Compounds of Phlomis viscosa Poiret

Abstract

Phlomis viscosa Poiret (an evergreen shrub) represents a valuable source of medicinal compounds. In this study, we discovered compounds with antimicrobial and antiviral properties. The aim of this study was to identify compounds of P. viscosa and estimate the antimicrobial and antiviral activity of its phytochemicals. The volatile compounds were identified using gas chromatography/mass spectrometry (GC/MS) analysis. For the identification of nonvolatile components of the extracts, high-performance liquid chromatography (HPLC), liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) were applied. Quercetin 3-O-rutinoside and hesperidin caused a significant decrease in the bacterial concentration of Agrobacterium tumefaciens, Xylella fastidiosa and Pseudomonas syringae (p < 0.001). The growth of drug-resistant microorganisms (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Serratia marcescens and Salmonella enteritidis) was inhibited by quercetin 3-O-rutinoside, quercetin 3-O-arabinoside and hesperidin. In addition, these compounds demonstrated antiquorum-sensing properties. Diosmin, hesperidin and quercetin 3-O-arabinoside significantly inhibited varicella zoster virus (VZV) (p < 0.001). Quercetin 3-O-rutinoside and quercetin 3-O-arabinoside were effective against herpes simplex virus 1 (HSV-1), including mutant strains.

Keywords: Phlomis viscosa; antimicrobial compounds; antiviral compounds; biofilm formation; drug-resistant microorganisms; flavonoids.

Figure 1

HPLC-MS (a) and GC-MS (b,c) chromatograms of extracts from leaves (a and b) and flowers (c) of P. viscosa. The peaks are numbered in the order of compounds listed in Table 1 and Table 2. GC chromatograms are presented in several patterns of ca. 10 min in appropriate signal scales. The GC chromatogram of flowers shows patterns of 0–10 min and 20–30 min since at 10–20 min, there were no identified peaks.

Figure 1

HPLC-MS (a) and GC-MS (b,c) chromatograms of extracts from leaves (a and b) and flowers (c) of P. viscosa. The peaks are numbered in the order of compounds listed in Table 1 and Table 2. GC chromatograms are presented in several patterns of ca. 10 min in appropriate signal scales. The GC chromatogram of flowers shows patterns of 0–10 min and 20–30 min since at 10–20 min, there were no identified peaks.

Figure 2

Effect of on eradication of Agrobacterium tumefaciens, Xylella fastidiosa and Pseudomonas syringae. The phytochemicals and streptomycin were at a concentration of 2 µM. Data from three independent experiments are shown. One asterisk designates data of no significant difference, and two asterisks show data of statistically proven difference (p < 0.001).

Figure 3

Effect of P. viscosa crude extract and its phytochemicals on the eradication of drug-resistant microorganisms (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Serratia marcescens and Salmonella enteritidis). The phytochemicals were applied at a concentration of 2 µM. Data from three independent experiments are shown. One asterisk designates data of no significant difference, and two asterisks show data of statistically proven difference (p < 0.001).

Figure 4

Effect of quercetin 3-O-rutinoside, quercetin 3-O-arabinoside and hesperidin on biofilm formation. The results are presented as the mean ± SE of the absorbance at 590 nm. Phytochemicals and streptomycin were used at a concentration of 2 µM. Data from three independent experiments are shown. One asterisk designates data of no significant difference, and two asterisks show data of statistically proven difference (p < 0.001).