1.Antimicrobial wound dressing film utilizing nano-cellulose and gelatin as drug delivery system for Garcinia mangostana L extract
Leong Chean Ring ; Tong Woei Yenn ; Suzana Wahidin ; Wen-Nee Tan ; Siti Zubaidah Binti Abdullah ; Nurul Aisyah Mohd Jamil ; Muhammad Sharir Abdul Rahman
Malaysian Journal of Microbiology 2019;15(5):373-378
Aims:
Diabetic patients with foot ulcer showed 150-fold increased risk of amputation, which is primarily caused by microbial infection. Silver ions are commonly incorporated into wound dressing to enhance the antimicrobial property. However, concerns have been expressed about the development of bacterial resistance to heavy metals. In this study, we extracted the nano-cellulose from medical cotton and reinforced with gelatin to develop a film for wound dressing.
Methodology and results:
Garcinia mangostana L pericarp extract was incorporated into the nano-cellulose film as antimicrobial finishing. The efficacy of the developed nano-cellulose film was evaluated on diabetic wound microorganisms. We observed cellulose nano crystals with an average length of 133.71 nm under transmission electron microscope. The developed film showed gradual release of the extract over a period of 48 h and no burst effect was observed. The film exhibited significant inhibitory activity on three Gram positive bacteria, three Gram negative and all filamentous fungi tested. On Hohenstein challenge test, all test microorganisms showed significant growth reduction, with the treatment of the film. We also noticed that the antimicrobial activity of the film sustained even after 20 washes.
Conclusion, significance and impact of study
Our results indicate that the G. mangostana L pericarp extract loaded nano-cellulose films exhibited significant inhibitory activity on diabetic wound microorganisms. The developed film can be potentially used to prevent foot ulcer infection among diabetic patients.
2.Antimicrobial activity of Aspergillus sp. IBRL MP15 CCL, an endophytic fungus isolated from Swietenia macrophylla leaf against human pathogens
Chean Ring LEONG ; Adib Arifah Binti Mansur ; Syarifah Abdul RASHID ; Swee Ngim ANG ; Wen-Nee TAN ; Woei Yenn TONG ; Darah IBRAHIM
Malaysian Journal of Microbiology 2018;14(1):49-54
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
3.Antimicrobial Efficacy of Penicillium amestolkiae elv609 Extract Treated Cotton Fabric for Diabetic Wound Care.
Nur Amiera Syuhada Binti ROZMAN ; Nurhanis Syafiqah Binti Mohd Nor HAMIN ; Leong Chean RING ; Tan Wen NEE ; Mahfuzah Binti MUSTAPHA ; Tong Woei YENN
Mycobiology 2017;45(3):178-183
Diabetes mellitus is a chronic disorder which affects millions of population worldwide. Global estimates published in 2010 reported the world diabetic prevalence as 6.4%, affecting 285 million adults. Foot ulceration and wound infection are major forms of disabilities arising from diabetic diseases. This study was aimed to develop a natural antimicrobial finishing on medical grade textile that meets American Association of Textiles Chemists and Colorists (AATCC) standard. The textile samples were finished with the ethanolic extract of Penicillium amestolkiae elv609, an endophytic fungus isolated from Orthosiphon stamineus Benth (common name: cat's whiskers). Endophyte is defined as microorganism that reside in the living plant tissue, without causing apparent disease symptom to the host. The antimicrobial efficacy of the ethanolic extract of P. minioluteum was tested on clinical pathogens isolated from diabetic wound. The extract exhibited significant inhibitory activity against 4 bacteria and 1 yeast with the minimal inhibitory concentration ranged from 6.25 to 12.5 mg/mL. The results indicate different susceptibility levels of the test microorganism to the ethanolic extract. However, the killing activity of the extract was concentration-dependent. The finished medical textile showed excellent antimicrobial efficacy on AATCC test assays. All the microbial cultures treated with the textile sample displayed a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 50 washes with commercial detergent. Besides, the gas chromatography mass spectrometry analysis showed that 6-octadecenoic acid and diethyl phthalate were the main bioactive constituents of the extract. In conclusion, the developed medical textile showed good antimicrobial efficacy on laboratory tests. This work can be extended to in vivo trials for developing healthcare textile products for antimicrobial applications.
Adult
;
Bacteria
;
Delivery of Health Care
;
Detergents
;
Diabetes Mellitus
;
Ethanol
;
Foot Ulcer
;
Fungi
;
Gas Chromatography-Mass Spectrometry
;
Homicide
;
Humans
;
Orthosiphon
;
Penicillium*
;
Plants
;
Prevalence
;
Textiles
;
Wound Infection
;
Wounds and Injuries*
;
Yeasts
4.Bioprospecting of Endophytic Fungi as Promising Anti-MRSA Agents
Yee-Min WEI ; Joo-Shun TAN ; Hock-Wei TANG ; Woei-Yenn TONG ; Chean-Ring LEONG ; Wen-Nee TAN
Natural Product Sciences 2022;28(3):93-104
Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to the global healthcare system. Ineffective and resistance to antibiotic treatments have increased morbidity and mortality rates worldwide.New and effective antibiotics are needed to combat against bacterial resistance. Endophytic fungi are crucial reservoirs of novel bioactive metabolites. In particular, the secondary metabolites show promising therapeutic potential, notably, antibacterial. This review discussed the emerging potential of endophytic fungi as anti-MRSA agents. The ecological sources of endophytic fungi were discussed with the synthesis of bioactive metabolites.The mode of antibacterial actions was elucidated to give a better understanding of the mechanisms involved. This review may serve as an important reference for future discovery and developments of anti-MRSA agents from endophytic fungi.
5.Anthocyanins from Clitoria ternatea Attenuate Food-Borne Penicillium expansum and its Potential Application as Food Biopreservative.
Chean Ring LEONG ; Muhammad Afif KAMARUL AZIZI ; Md Abu TAHER ; Suzana WAHIDIN ; Kok Chang LEE ; Wen Nee TAN ; Woei Yenn TONG
Natural Product Sciences 2017;23(2):125-131
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.
Anthocyanins*
;
Asian Continental Ancestry Group
;
Clitoria*
;
Diffusion
;
Fungi
;
Germination
;
Gram-Negative Bacteria
;
Gram-Positive Bacteria
;
Humans
;
Hyphae
;
Peas
;
Penicillium*
;
Spores, Fungal
6.Chemical Composition and Antimicrobial Efficacy of Helminthostachys zeylanica against Foodborne Bacillus cereus
Tong Woei YENN ; Leong Chean RING ; Khairul Azly ZAHAN ; Muhammad Sharir ABDUL RAHMAN ; Wen Nee TAN ; Bintul Jauza' SHAIK ALAUDIN
Natural Product Sciences 2018;24(1):66-70
Helminthostachys zeylanica is a rare plant grows in lightly shaded areas. The fern was traditionally used as antipyretic and antiphlogistic agents. This study was aimed to evaluate the antibacterial potential of H. zeylanica on foodborne Bacillus cereus. The chemical composition of its ethanolic extract was also determined. The plant samples were collected at Kampung Kebun Relong, Kedah, Malaysia. The ethanolic extract showed significant inhibitory activity on B. cereus with a sizeable clear zone detected on disc diffusion assay. On broth microdilution assay, the MIC of the extract on B. cereus was 6.25 mg/ml and the MBC was 12.5 mg/ml. The inhibitory activity of the extract on B. cereus was bactericidal. In the growth dynamic study, the antibacterial efficacy of the extract was concentration dependent, where a lower colony forming unit count was obtained with increased extract concentration. The SEM micrograph of extract treated B. cereus cells showed invaginations of cell wall. The bacterial cell structure collapsed after 24 h exposure to the extract. The GCMS analysis of the extract showed that the major constituents of the extract were phenol (36.26%) and quercetin (29.70%). This study is important as it shows the potential use of H. zeylanica as an effective agent to control B. cereus related infections.
Bacillus cereus
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Bacillus
;
Cell Wall
;
Diffusion
;
Ethanol
;
Ferns
;
Gas Chromatography-Mass Spectrometry
;
Malaysia
;
Phenol
;
Plants
;
Quercetin
;
Stem Cells
7.Chemical Composition and Antimicrobial Efficiency of Swietenia macrophylla Seed Extract on Clinical Wound Pathogens
Hanan Kumar GOPALAN ; Nor Faizzah MD HANAFIAH ; Leong CHEAN RING ; Wen Nee TAN ; Suzana WAHIDIN ; Teo Siew HWAY ; Tong Woei YENN
Natural Product Sciences 2019;25(1):38-43
Microbial wound infection prolonged the hospitalization and increase the cost for wound management. Silver is commonly used as antimicrobial wound dressing. However, it causes several adverse side effects. Hence, this study was aimed to evaluate the antimicrobial efficiency of Swietenia macrophylla seed extract on clinical wound pathogens. Besides, the bioactive constituents of the seed extract were also determined. S. macrophylla seeds were extracted with methanol by maceration method. The seed extract inhibited 5 test bacteria and 1 yeast on disc diffusion assay. The antibacterial activity was broad spectrum, as the extract inhibited both Gram positive and Gram negative bacteria. On kill curve analysis, the antibacterial activity of the seed extract was concentration-dependent, the increase of extract concentration resulted in more reduction of bacterial growth. The extract also caused 99.9% growth reduction of Bacillus subtilis relative to control. A total of 21 compounds were detected in gas chromatography-mass spectrometry analysis. The predominant compounds present in the extract were oleic acid (18.56%) and linoleic acid (17.72%). In conclusion, the methanolic extract of S. macrophylla seeds exhibited significant antimicrobial activity on clinical wound pathogens. Further investigations should be conducted to purify other bioactive compounds from the seeds of S. macrophylla.
Bacillus subtilis
;
Bacteria
;
Bandages
;
Diffusion
;
Gas Chromatography-Mass Spectrometry
;
Gram-Negative Bacteria
;
Hospitalization
;
Linoleic Acid
;
Meliaceae
;
Methanol
;
Methods
;
Oleic Acid
;
Silver
;
Wound Infection
;
Wounds and Injuries
;
Yeasts
8.Chemical compositions and in vitro antimicrobial activity of Cymbopogon nardus on food borne microorganisms
Wen-Nee Tan ; Woei Yenn Tong ; Chean Ring Leong ; Nor Faizzah Md Hanafiah ; Nur Sufina Ridzuan ; Nur Amiera Syuhada Rozman ; Sharifah Soplah Syed Abdullah
Malaysian Journal of Microbiology 2018;14(7):699-704
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.
9.In vitro antibacterial activity of endophytic fungus Aspergillus flavus IBRL-C8 from Senna siamea against Gram-bacteria
Nurhaida ; Darah Ibrahim ; Syarifah Ab Rashid ; Tong Woei Yenn
Malaysian Journal of Microbiology 2021;17(1):35-41
Aims:
To evaluate the antibacterial efficacy of ethyl acetate extract of Aspergillus flavus IBRL-C8 against Gram-positive
and Gram-negative bacteria.
Methodology and results:
In this experiment, an endophytic fungus which identified as A. flavus IBRL-C8 was
extracted using ethyl acetate and methanol, from Senna siamea, prior to in vitro antibacterial test on eight Gram-bacteria. The results were significantly more enunciated to the ethyl acetate extract since the Gram-bacteria signified 9.0
to 20.0 mm of inhibition zones on Muller Hinton Agar (MHA) during disc diffusion assay. Minimal inhibitory concentration
(MIC) and minimal bactericidal concentration (MBC) of the extract were ranged from 125-1000 µg/mL and 125-2000
µg/mL, respectively. Time-kill assay depicted the ethyl acetate extract of A. flavus IBRL-C8 exceptionally retarded
methicillin-resistant Staphylococcus aureus (MRSA) and also manifested extended antibacterial activity. The maximum
reduction in cell numbers occurred at 2MIC concentration (250 µg/mL) during the interval time of 16 h. The
malformations noticed from microscopic observations where the transformation of structural annihilation from regular
spherical morphology to non-spherical shape with an irregular surface and also disruption around the cell membrane
when the MRSA treated with ethyl acetate extract of A. flavus IBRL-C8.
Conclusion, significance and impact of study
This study proposed the ethyl acetate extract of A. flavus IBRL-C8 as
a potential antibacterial agent against MRSA infection, which can be useful in pharmaceutical application.
Aspergillus flavus
;
Anti-Bacterial Agents
10.Purification and physicochemical characterisation of Aspergillus niger USM F4 β-mannanase
Ab Rashid Syarifah ; Ibrahim Darah ; Che Omar Ibrahim ; Hassan Ramli ; Woei Yenn Tong
Malaysian Journal of Microbiology 2020;16(5):396-406
Aims:
This present study focused on purification of fungal β-mannanase produced by Aspergillus niger USM F4 and
also physicochemical characterisation of the purified enzyme.
Methodology and results:
The purified β-mannanase with a molecular mass of ~47.4 kDa was demonstrated on SDSPAGE gel. The enzyme signified a purification degree of 4-fold, with final specific activity of 196.42 U/mg. It reached an
optimum catalytic activity at pH 4.0 and 60 °C. The thermal stability of the enzyme was up to 70 °C and maintained the
50% activity after 30 min at 80 °C. Meanwhile, the pH stability was in the range of pH 3.0-9.0 and a 30 min half-life at pH
10.0. All chemical substances manifested an inhibitory effect on purified β-mannanase, with SDS (28.16 ± 0.05%
residual activity) as the strongest inhibitor, followed by cupric ion (Cu2+) (49.51 ± 0.09% residual activity). As a whole, the
enzyme displayed a substrate specificity in the order of locust bean gum (LBG) > carboxymethylcellulose > soluble
starch > xylan from oat spelt > α-cellulose. Its preference for LBG has generated the Km and Vmax values of 0.20 mg/mL
and 9.82 U/mL, respectively.
Conclusion, significance and impact of study
The outcomes of our study offer potential for use at industrial scales,
particularly in the oligosaccharides production that involve acid-related activity, wide-ranging temperature and pH
stability.
Aspergillus niger
;
beta-Mannosidase