Antibacterial and Antioxidant Effects of Three Chlorogenic Acid Extracts

[Objectives] To study the antibacterial and antioxidant effects of chlorogenic acid extracts of Gynura procumbens,Lonicera japonica,and Eucommia ulmoides leaves,and provide a reference for their usage as natural food preservatives and antioxidants. [Methods]The disc diffusion method was applied to study the antibacterial activity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves against several common pathogens. In the antioxidant effects,study was carried out on the anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,respectively.[Results]Three chlorogenic acid extracts had strong inhibitory effects on bacteria,especially the inhibition on Staphylococcus aureus. At the concentration of 100 mg/m L,the bacteriostatic ring of chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves reached 21. 4,23. 6 and 24. 7 mm respectively. Besides,these chlorogenic acid extracts had significant inhibitory effect on Escherichia coli and Salmonella,but the inhibitory effect on the yeast was not obvious; the antibacterial intensity of antibacterial compounds was chlorogenic acid extracts of E. ulmoides > chlorogenic acid extracts of L. japonica > chlorogenic acid extracts of G. procumbens. Among these three chlorogenic acid extracts,the chlorogenic acid extracts of E. ulmoides had higher anti-lipid peroxidation,reducing capacity,and DPPH free radical scavenging capacity than other two chlorogenic acid extracts. [Conclusions] This paper reveals that among chlorogenic acid extracts of G. procumbens,L. japonica,and E. ulmoides leaves,the chlorogenic acid extracts of E. ulmoides leaves have a stronger antibacterial activity and antioxidant activity.

Antibacterial and Antioxidant Activity of Rhodomyrtus Tomentosa and Cinnamomum Zeylanicum Crude Extracts

The aim of this study was to investigate the extraction method for R.to­mentosa and C.zeylanicum leaves and the evaluation of antibacterial and antioxidant activities of crude extracts.The results of the study showed that the active ingredients of crude extracts were clearly separated by Thin-layer chromatography and the presence of rhodomyrtone in R.tomentosa crude extract and cinnamaldehyde in C.zeylanicum crude ex­tract.R.tomentosa crude extract was antibacterial activity against Staph­ylococcus aureus with 13.1 mm of inhibition zone,but is not effective against Salmonella Typhimurium.C.zeylanicum leaf extract did not show antibacterial activity on both S.aureus and S.Typhimurium.At a dilution of 1/2 of the R.tomentosa crude extract can completely inhibit S.aureus growth.This study also indicated the presence of antioxidant compounds such as flavonoids,tannins,phenols and terpenoids in C.zeylanicum and R.tomentosa crude extracts.The results showed that R.tomentosa and C.zeylanicum crude extracts should be used as a biotherapy alternative to antibiotic therapy.However,further study would be needed to investigate the antibacterial activity of crude extracts in vivo.

Electrospun gelatin/chitosan nanofibers containing curcumin for multifunctional food packaging

Recently,food grade nanofiber-based materials have received growing attentions in food packaging.In this work,novel active and intelligent packaging nanofibers based on gelatin/chitosan with curcumin(GA/CS/CUR)were developed via electrospinning technique.Effects of the incorporation of CUR content(0.1%-0.3%,m/m)on the microstructure and functional properties of the electrospun nanofibers were investigated.Morphological studies using scanning electron microscopy indicated that loading CUR can affect the average diameter of nanofiber mats,which remained around 160-180 nm.The addition of an appropriate level CUR(0.2%,m/m)led to a stronger intermolecular interaction,and thus enhanced the thermal stability and tensile strength of the obtained nanofibers.Meanwhile,the incorporation of CUR significantly improved antioxidant activity and the antimicrobial activity of GA/CS/CUR nanofibers.Moreover,the sensitivity of nanofibers to ammonia results indicated that GA/CS nanofibers containing 0.2%CUR(GA/CS/CURⅡ)presented high sensitivity of colorimetric behavior to ammonia(within 3 min).These results suggest GA/CS/CURⅡnanofibers has great potential as a multifunctional packaging to protect and monitor the freshness of proteinrich animal foods,such as meat and seafood.

Antibacterial,antioxidative and sensory properties of Ziziphora clinopodioides–Rosmarinus officinalis essential oil nanoencapsulated using sodium alginate in raw lamb burger patties

This study was aimed to encapsulate Ziziphora clinopodioides –Rosmarinus officinalis essential oil (Z-REO) using sodium alginate (NaAlg) and to evaluate its performance on antimicrobial and antioxidative activities and sensory attributes in lamb burger patties during cold storage for 12 days.GC-MS analysis of Z-REO indicated carvacrol (21.5%) and thymol (16.9%) were the major components.SEM images showed the formation of encapsulated particles.The presence of encapsulated Z-REO in NaAlg was proved based on the increase in band intensity of FTIR spectra.By increasing mass ratios of NaAlg:Z-REO from 1:1 to 2:1,and 4:1,encapsulation efficiency was increased.Average zeta-potential values (mV) of the mass ratios 4:1 and 2:1 were −48.67 and −44.83,indicating the stability of encapsulated particles.The average size of particles ranged from 159.14 nm to 256.14 nm.The results showed that the encapsulated nanoparticles could markedly decrease the growth of inoculated Escherichia coli O157:H7 and Staphylococcus aureus and delay the lipid oxidation of lamb patties compared to the control samples and in samples with free Z-REO.Furthermore,nanoparticles efficiently decreased discoloration and off-odor development in the patties.Therefore,NaAlg-Z-REO nanoparticles could efficiently reduce bacterial growth and oxidative or sensory deterioration of lamb patties during storage.

Antibacterial and Antioxidant Activities of ZnO Nanoparticles Synthesized Using Extracts of Allium sativum,Rosmarinus officinalis and Ocimum basilicum

ZnO nanoparticles（ZnO NPs） were synthesized by chemical method（coprecipitation） and biological method using aqueous extracts of garlic（Allium sativum）,rosemary（Rosmarinus officinalis） and basil（Ocimum basilicum）.The influence of plant extract on the antibacterial and antioxidant activities of green synthesized nanoparticles was investigated.The X-ray diffraction studies reveal that all ZnO samples have hexagonal wurtzite structure.The particle size of ZnO NPs estimated by transmission electron microscopy analysis（between 14 and 27 nm） varies depending on the synthesis method of nanoparticles and the type of extracts from the plants used.The functional groups involved in the biosynthetic procedure were evidenced by Fourier transform infrared spectroscopy.The presence of Mn^（2＋）ions,Zn vacancy complexes and oxygen vacancies in ZnO samples was highlighted by electron paramagnetic resonance spectroscopy.The green synthesized ZnO NPs have shown a good bactericidal activity against Staphylococcus aureus,Bacillus subtilis,Listeria monocytogenes,Escherichia coli,Salmonella typhimurium and Pseudomonas aeruginosa bacterial strains.ZnO NPs synthesized using extracts of the selected plant species have been found to exhibit more enhanced antibacterial and antioxidant activities as compared to chemical ZnO NPs.