In vitro and in vivo antimicrobial efficacy of natural plant-derived compounds against Vibrio cholerae of O1 El Tor Inaba serotype

Abstract

Shin (2015) Invitro and invivo antimicrobial efficacy of natural plant-derived compounds against Vibriocholerae of O1 El Tor Inaba serotype, Bioscience, Biotechnology, and Biochemistry, 79:3, 475-483, DOI: 10.1080/09168451.2014 In this study, we investigated antibacterial activities of 20 plant-derived natural compounds against Gram-negative enteric pathogens. We found that both flavonoids and non-flavonoids, including honokiol and magnolol, possess specific antibacterial activities against V. cholerae, but not against other species of Gram-negative bacterium which we tested. Using various antibacterial assays, we determined that there was a dose-dependent bactericidal and biofilm inhibitory activity of honokiol and magnolol against Vibrio cholerae. In addition to antibacterial activities, these molecules also induced an attenuating effect on reactive oxygen species (ROS) production and pro-inflammatory responses generated by macrophages in response to lipopolysaccharides (LPS). Additionally, Caenorhabditis elegans lethality assay revealed that honokiol and magnolol have an ability to extend a lifespan of V. choleraeinfected worms, contributing to prolonged survival of worms after lethal infection. Altogether, our data show for the first time that honokiol and magnolol may be considered as attractive protective or preventive food adjuncts for cholera.

Synthesis of Either C2- or C4′-Alkylated Derivatives of Honokiol and Their Biological Evaluation for Anti-inflammatory Activity

“…Honokiol and 4′-O-methylhonokiol consist of a 5,3′-diallylbiphenyl skeleton bearing hydroxy group in the C2 of the A ring, or hydroxyl and methoxy groups in the C4′ of the B ring, respectively. The previous study 11) showed that 4′-O-methylhonokiol exerts higher anti-inflammatory activity than those of honokiol and various honokiol analogs, as examined using COX-1 and COX-2 enzyme assay and LTB4 formation assay. Thus, we contemplated efficient synthesis of mono-alkylated analogs on either the 2-or 4′-position for elongating the regioselective chain and designing site-selective photoaffinity probes, which would be useful to elucidate directly binding proteins, as shown in Fig.…”

“…In a previous study, we found that modifications of 4′-Omethylhonokiol through introduction of methyl, isopropyl, and prenyl groups at phenol slightly decrease the inhibitory activity of COX-2 enzyme. 11) Compared with other synthesized analogs, 11a showed the most promising anti-inflammatory activity; thus, it was exploited as an intermediate to obtain C4′-labeled photoaffinity probe of honokiol. 25) By the treatment with trifluoroacetic acid in dichloromethane, the tertbutyl ester group of 11a was removed to afford carboxylic acid 12, as shown in Chart 2.…”

“…7) Biphenolic natural neolignans isolated from the bark of Magnolia officinalis, such as honokiol, 4′-O-methylhonokiol, magnolol, and obovatol, have been used as traditional medicines for treating gastrointestinal disorders, anxiety, and allergy. Recent studies revealed that honokiol and its analogs have various biological activities, such as antiangiogenesis, 8,9) anticancer, 10) anti-inflammatory, 11) antibacterial, 12) osteoclast genesis-suppressing, 13) hepatoprotective, 14) and neuroprotective activities. 15) Honokiol and its derivatives were reported to target multiple signaling pathways, including the nuclear factor kappa light chain enhancer of activated B cells (NF-κB), 16) p53, 17) epidermal growth factor receptor (EGFR), 18) GPR55, 19) and phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathways.…”

“…20) Previously, we have synthesized a series of derivatives of honokiol and 4′-O-methylhonokiol for improved inhibitory activities against COX-2 and PGF 1 production. 11) Some analogs were found to prevent NO production in LPS-activated macrophages. 20) Recently, the anti-neuroinflammatory effects of honokiol on heterocyclic bioisosteres in LPS-activated BV-2 cells have been reported.…”

Wogonin inhibits Varicella-Zoster (shingles) virus replication via modulation of type I interferon signaling and adenosine monophosphate-activated protein kinase activity

“…Wogonin was isolated from the roots of S. baicalensis using a previously described method (Kim et al, 2001) and honokiol and magnolol were also reported previously (Kim et al, 2015).…”