ABSTRACT
Aims@#This research was conducted to develop and characterize polyvinyl alcohol (PVA)/montmorillonite (MONT) clay incorporated with carvacrol (Carva) nanocomposite film as a potential material in wound dressing.@*Methodology and results@#Organophilic MONT clay, which was initially modified from commercial MONT clay by cetyltrimethylammonium bromide (CTAB), was used in the polymerization process using PVA. The synthesized nanocomposites were visualized via transmission electron microscopy (TEM). The developed film (PVA/MONT/Carva nanocomposite film) was characterized via Fourier transform infrared (FTIR). The investigation on mechanical property and antimicrobial activity of the film was also performed. All nanocomposites are spherical, with a size of 92.8 ± 22.1 nm. The -OH stretch, C-H stretch, aromatic group, SiO stretch, and C-O from acetyl group were identified in the PVA/MONT/Carva nanocomposite films. During the chemical release test, carvacrol attained a plateau at 24 h, with a total release of 62.3%. This nanocomposite exhibited a severe detrimental influence on the growth of Gram-bacteria and yeasts, which represented a broad spectrum of antimicrobial agents. All test microorganisms showed approximately up to 82% reduction of microbial growth during the Hohenstein challenge test. Physically, the nanocomposite films were yellowish and apparent. The film was sturdy, flexible, elastic and consisted of excellent water holding capacity.@*Conclusion, significance and impact of study@#PVA/MONT/Carva nanocomposite film may have a useful potential to be merged in the pharmaceutical application, especially in wound dressing production.
Subject(s)
Polyvinyl Alcohol , Bentonite , Wound HealingABSTRACT
@#Aims: Endophytes are microorganisms residing in the living tissues of the host plant and may contribute to their hostplant by producing a plethora of bioactive compounds that provide survival value to the plant. This study aimed toevaluate the antimicrobial activity of Aspergillus sp. IBRL MP15 CCL, an endophytic fungus isolated from Swieteniamacrophylla leaf.Methodology and results: The antimicrobial activity was evaluated with disc diffusion and a colorimetric brothmicrodilution test against 15 organisms comprising of 4 Gram-positive bacteria and 4 Gram-negative bacteria, 4 fungiand 3 yeast. On disc diffusion assay, the fungal extract was shown to inhibit the growth of 7 test bacteria and 3 testyeast. The antibacterial activity was more pronounced with extract from fungal culture with host plant extractsupplementation with significantly larger inhibition zones on all susceptible test microorganisms. The minimal inhibitoryconcentration of the extract ranged from 250 to 4000 μg/mL indicating different level of susceptibility of the testedpathogens against the fungal extract. The killing kinetic study shows that antimicrobial activity of the fungal extract isconcentration dependent and it can act as bactericidal at higher concentration.Conclusion, significance and impact of study: The findings of this study suggest that Aspergillus sp. IBRL MP15CCL can be a promising source of antimicrobial agent to be further studied and developed
ABSTRACT
Aims@#Food borne infections are routinely observed and frequently reported. Cymbopogon nardus, or commonly known as citronella is a tropical plant widely used for aromatherapy and insect repellant. This study aimed to evaluate the phytochemical compositions of C. nardus ethanol extract and its antimicrobial activity on food borne microorganisms. @*Methodology and results@#The plant materials were extracted with ethanol using maceration technique. The ethanol extract obtained was analysed using GC-MS and the most abundant compounds were 6-methyloctahydrocoumarin (31.5%) and 2,4-di-tert-butylphenol (28.7%). On Kirby Bauer assay, the extract showed wide spectrum inhibitory effect on one Gram-positive bacteria (Bacillus coagulans), two Gram-negative bacteria (Proteus mirabilis and Escherichia coli), and one yeast (Candida albicans). All the test microorganisms showed different susceptibility to the extract, where the minimal inhibitory concentrations were ranged from 63 to 250 μg/mL. The inhibitory effect of the extract was bactericidal. In addition, the time kill analysis of the extract exhibited inhibitory effect on P. mirabilis which was concentration-dependent. The C. nardus extract exhibited rapid bactericidal effect on P. mirabilis and lower bacterial counts were obtained with increased extract concentration. Besides, the extract did not exert significant toxicity effect to Artemia salina on brine shrimp lethality assay. @*Conclusion, significance and impact of study@#Therefore C. nardus can be a potential source of safe and effective antimicrobial agent to combat food borne infections.
ABSTRACT
Clitoria ternatea or Commonly known blue pea, is a perennial climber crop native to Asian countries. The current study was aimed to evaluate the antimicrobial activity C. ternatea extract on food borne microorganisms and its antifungal effect on Penicillium expansum. The extract showed significant antimicrobial activity against 3 Gram positive bacteria, 2 Gram negative bacteria and 1 filamentous fungus on disc diffusion assay. The extract also showed good biocidal effect on all Gram positive bacteria tested and P. expansum. However, the kill curve analysis revealed that the fungicidal activity of the extract against P. expansum conidia was depend on the concentration of the extract and the time of exposure of the conidia to the extract. The scanning electron micrograph of the extract treated P. expansum culture showed alterations in the morphology of fungal hyphae. The germination of P. expansum conidia was completely inhibited and conidial development was totally suppressed by the extract, suggesting the possible mode of action of anthocyanin. Besides, the extract also exhibited 5.0-log suppression of microbial growth relative to control in the rice model. The results indicate the potential use of the C. ternatea anthocyanin as food biopreservative.