Veratrole Research Articles

Effect of plant-based catecholic molecules on the prevention and eradication of Escherichia coli biofilms: A structure activity relationship study

Persistent bacterial infections and increased resistance to multidrugs are mostly related with biofilm formation which constitute a global concern in nowadays society. Therefore, studies must be conducted in order to discover more efficient antibiofilm agents. Nine compounds with a catecholic moiety (catechol (CAT), veratrol (VER), guaiacol (GUA), 2-ethoxphenol (ETH), 4-methylcatechol (MEC), 4-tert-butylcatechol (TEB), pyrogallol (PYR), 3-methoxycatechol (MET), and o-phenylene-phosphochloridite (OPP)) were investigated for their potential to prevent and eradicate Escherichia coli biofilms. Their action was assessed on biomass and metabolic activity, sessile cells' membrane integrity and culturability, motility and cell surface hydrophobicity (CSH). ETH, MEC, TEB, PYR and OPP exhibited the best antibiofilm activities among the tested catechols, inducing biofilm removal and metabolic inactivation, sessile cells' membrane disruption and death. CAT, TEB and PYR significantly inhibited E. coli swimming motility. Likewise, ETH, MEC, TEB and PYR significantly reduced E. coli CSH. An additive interaction of combined catechols with ciprofloxacin was attained in both control and preventive strategies. From a structure activity relationship (SAR) study, an increase in the hydrocarbon side chain and lipophilicity using ETH and TEB as scaffolds is suggested for increased activity. Hydroxyl groups are also suggested to be particularly related to their antibiofilm activity. All the catechols fulfil the Lipinski's “rule of five” requisites and thus are promising scaffolds in the development of new formulations for therapeutic purposes.

Meligethes aeneus pollen-feeding suppresses, and oviposition induces, Brassica napus volatiles: beetle attraction/repellence to lilac aldehydes and veratrole

Insect pollination and pollen feeding can reduce plant volatile emissions and future insect floral attraction, with oviposition having different effects. Meligethes aeneus F. (Coleoptera: Nitidulidae), is a pollen-feeding pest beetle of oilseed rape, Brassica napus L. (Brassicaceae). We measured plant VOC emission over 72 h from two types of 24 h M. aeneus exposure to B. napus: pollen feeding vs. flower bud injury and oviposition. The most abundant constitutive volatile organic compounds (VOCs), lilac aldehydes A (LA A) & B (LA B) and veratrole (VER), had 30–40 % reductions from M. aeneus pollen-feeding exposure at 24 h and 50–90 % reductions by 72 h, with greater reductions after bud injury and oviposition. Linalool (LIN), a common herbivore-induced plant volatile (HIPV), emission did not change at 24 h, but was induced six- to sevenfold 48 h after both exposure treatments. By 72 h, LIN had even greater (tenfold) induction after bud injury and oviposition, but no induction from pollen feeding. Three common HIPVs (β-caryophyllene, = βCAR (E)-β-farnesene = EβFAR, and (Z)-β-ocimene = ZβOCI) were progressively induced up to 2.5-fold 72 h after floral bud injury and oviposition. We assayed M. aeneus adult behavioral responses to LA A and B, and VER. Both M. aeneus sexes were attracted to higher concentrations than single plant constitutive emission for these VOCs, but avoided much higher doses. Progressive LA A and B, and VER, emission reductions might help plants (e.g., B. napus) to avoid future interactions with pollen-feeding pest herbivores (e.g., M. aeneus). After bud injury and oviposition, HIPV induction could help plants deter future oviposition and/or attract natural enemies to deposited eggs.

Research of mechanism about enhancing the activity of γδδT cells treated by resveratrol on colonic cancer cell lines SW-1116

Objective To explore the effect of γδT cells on colonic cancer cell lines SW-1116 treated by resveratrol. Methods Amplification γδT cells of human peripheral blood in vitro by using isopentenylpyrophosphate. Different density resveratrol induced γδT cells and colonic cancer cell SW-1 116, methyl thiazolyl tetrazolium(MTT) detectde the effect of growth and proliferation when expression veratrol action to γδT cells and colonic cancer cell lines SW-1116. Flow cytometer( FCM )detectde the expression of porforin, granzymeB and CD107a on γδT cells before it treated by resveratrol and after that. γδT cells against colonic cancer cell lines SW-1116 were detectde by lactate dehydrogenase(LDH) releasing assay before and after treated by resveratrol.Western blot analyzed the liveness of extracellular signal-regulated kinase1/2 of γδT cells before it treated by resveratrol and after that. Results γδTcells would be proliferation when the density of resveratrol in 0.39-3.125 μmol/L, while the effect on colonic cancer cell lines SW-1116 was not significance. There was significant difference of the expression of porforin, ranzymeB and CD107a on γδT cells before it treated by resveratrol and after that ( P＜0.05 ). γδT cells against colonic cancer cell lines SW-1116 treated by resveratrol was enhanced compared with control group( P＜0.05 ) . The p-ERK 1/2expression of γδT cells enhanced when the density of resveratrol treated to γδT cells in 0.1-10 μmol/L( P＜0.05 ). Conclusion Resveratrol could promote γδT cells, proliferation and strengthen the cytotoxicity of γδT cells against colonic cancer cell SW-1116, the mechanism might concerned with activating p-ERK1/2 and enhancing the expression of porforin, granzymeB and CD107a on γδT cells. Key words: Resveratrol; Colon cancer cells; γδT cells

Polycyclic Aromatics from Veratrole and Ninhydrin and Acenaphthenequinone.

Treatment of 2,2-di(3,4-dimethoxyphenyl)indane-1,3-dione with concentrated sulfuric acid gives 2,3,6,7-tetramethoxydibenzo[a,c]fluoren-13-one while under the same conditions 2,2-di(3,4-dimethoxyphenyl)acenaphthenone produces 2,3,6,7-tetramethoxydibenzo[j,l]fluoranthene.

Polycyclic Aromatics from Veratrole and Ninhydrin and Acenaphthenequinone

Treatment of 2,2-di(3,4-dimethoxyphenyl)indane-1,3-dione with concentrated sulfuric acid gives 2,3,6,7-tetramethoxydibenzo[a,c]fluoren-13-one while under the same conditions 2,2-di(3,4-dimethoxyphenyl)acenaph-thenone produces 2,3,6,7-tetramethoxydibenzo[j,l]fluoranthene.

The influence of non-phenolic mediators and phenolic co-substrates on the oxidation of 4-bromophenol by lignin peroxidase

Lignin peroxidase (LIP) catalyzed oxidation of 4-bromophenol (4-BP) resulted in the formation of dimers as evidenced by GC-MS analysis. However, 4-BP was considered a poor substrate, since it exhibited a high Km value of 600.9 μM and during oxidation, LIP was subjected not only to H2O2- but also product-dependent inactivation. Oxidation was enhanced by inclusion of gelatin, which suppressed product-dependent inactivation and by inclusion of the dimethoxylated non-phenols, veratrole (VO) and 3,4-dimethoxycinnamic acid (DMCA) which mediated 4-BP oxidation. The mediation role of VO and DMCA is attributed to their oxidation potential (OP) values in the aqueous phase (6.04 eV for VO and 6.03 eV for DMCA), which implies that once oxidized to their respective cation radicals, they preferentially oxidize substrates of lower OP (5.12 eV for 4-BP phenolate ion). Inclusion of the mediators enabled complete 4-BP oxidation at high H2O2 concentrations, overcoming H2O2-dependent inactivation. When the reactive ferulic acid (FA) was included as a co-substrate, its oxidation preceded that of 4-BP, and since LIP was inactivated in the process, no oxidation of 4-BP was noticed. In the case of horseradish peroxidase (HRP), 4-BP oxidation was enhanced by inclusion of FA, even though oxidation of the latter preceded that of 4-BP. Additional studies indicated that this resulted from interaction of FA-oxidation products with 4-BP. In the presence of caffeic acid and catechol, reduced oxidation of 4-BP was evident for both enzymes. In the presence of syringaldehyde, concomitant oxidation was evident for both enzymes, resulting in enhanced oxidation by HRP and moderate-to-slight enhancement by LIP.

Selective propionylation of veratrole to 3,4-dimethoxypropiophenone using zeolite H-beta catalysts

The catalytic liquid phase propionylation of veratrole (VT) (1,2-dimethoxybenzene, 1,2-DMB) is investigated over a number of zeolite catalysts. Zeolite H-beta is found to be an effective catalyst for the selective conversion of VT to 3,4-dimethoxypropiophenone (3,4-DMPP). The SiO 2/Al 2O 3 ratio of zeolite H-beta is higher (SiO 2/Al 2O 3)=26 than the H–Y and RE (70.6)-Y (SiO 2/Al 2O 3=4.1). The performance of zeolite H-beta is compared with that of conventional catalyst, AlCl 3. The conversion of VT, the rate (turn over frequency, TOF) of VT conversion (10 −4 s −1 mol −1 Al), turnover number (TON) (mol of VT converted per mol Al in the catalyst) and the selectivity to 3,4-DMPP over H-beta after 1 h reaction time and at 403 K are found to be 40.8 wt.%, 18.8×10 −4 s −1 mol −1 Al, 67.8 and 89 wt.%, respectively. For comparison, the conversion of VT, TOF, TON and selectivity to 3,4-DMPP over AlCl 3 under identical reaction conditions are estimated to be 48.5 wt.%, 3.6×10 −4 s −1 mol −1 Al, 1.3 and 68.9 wt.%, respectively. The acidity of the zeolite catalysts is measured by the temperature programmed desorption (TPD) of ammonia. The effects of acidity of the zeolite catalysts, reaction time, catalyst concentration, reaction temperature and VT to propionyl chloride (PC) molar ratio on the catalyst performance are examined in order to optimise the conversion of VT and selectivity to 3,4-DMPP. The conversion of VT increases with the increase in reaction time, catalyst concentration and reaction temperature, whereas it decreases with the increase VT/PC molar ratio. The propionylation of 1,3-dimethoxybenzene (1,3-DMB) and 1,4-dimethoxybenzene (1,4-DMB) is also investigated over zeolite H-beta catalyst. The zeolite H-beta was recycled two times with a marginal decrease in catalytic activity, but without the loss of 3,4-DMPP selectivity and crystallinity of H-beta. Mechanistically, the PC is first polarised (CH 3CH 2CO δ+ , Cl δ− ) by the zeolite catalyst. The generated electrophile (CH 3CH 2CO +) attacks the ring of VT, resulting in the formation of 3,4-DMPP.

LXVIII.—The bromination of some derivatives of veratrole

LXVIII.—The bromination of some derivatives of veratrole