The Journal of Alternative and Complementary Medicine, 2014
Household ancient remedies reported here are described in the National List of Essential Medicine... more Household ancient remedies reported here are described in the National List of Essential Medicines and have traditionally been used in Thailand to treat infection-related ailments. However, the safety and effectiveness of these remedies have been poorly evaluated. The aim of this study was to evaluate the antibacterial properties of these remedies against seven gram-positive and gram-negative multidrug-resistant bacteria species. Phytochemical constituents and cytotoxicity of these remedies were also determined. Seven remedies, consisting of Um-Ma-Luk-Ka-Wa-Tee, Chan-Ta-Lee-La, Kheaw-Hom, Learng-Pid-Sa-Mud, Pra-Sa-Chan-Dang, Dhart-Ban-Chob, and Tree-Hom, were prepared by a licensed traditional medical doctor using a mixture of medicinal plants. Antibacterial activity of ethanol extracts of the remedies was determined by using a broth microdilution method. Qualitative phytochemical screening analysis was carried out to identify the presence of major components. Cytotoxicity activities of the extracts against Vero cells were assessed by green fluorescent protein-based assay. With the exception of Dhart-Ban-Chob extract, significant minimum inhibitory concentrations (MICs) of <16 to 32 μg/mL were observed for the remedy extracts depending on the bacterial strains. The Um-Ma-Luk-Ka-Wa-Tee extract was noncytotoxic against Vero cells and possessed the highest activity, with MICs of <16 to 31 μg/mL against all methicillin-resistant Staphylococcus aureus isolates. Remarkable antibacterial activities against multidrug-resistant pathogens, as well as low toxicity on Vero cells, of Um-Ma-Luk-Ka-Wa-Tee support the use of this remedy in traditional medicine. Further investigation on other biological activities related to traditional applications, appropriate biomarkers, and treatment mechanisms of the household remedy are required.
The adherence of oral pathogenic microorganisms to host tissues is the initial step for successfu... more The adherence of oral pathogenic microorganisms to host tissues is the initial step for successful process of oral diseases. This study aimed to determine the effect of the Rhodomyrtus tomentosa leaf extract and rhodomyrtone, an antibacterial compound from R. tomentosa leaf, on adhesion of some oral pathogens to polystyrene plastic surface and human buccal epithelial cells. The minimum inhibitory concentration (MIC) was evaluated using broth microdilution method. The microbial adhesion to the plastic surface and buccal cells was determined using microtiter plate method and microscopy technique. The ethanol extract of leaf demonstrated antibacterial activity against oral microorganisms including Staphylococcus aureus ATCC 25923, Streptococcus mutans (clinical isolate), and Candida albicans ATCC 90028 with the MIC values of 31.25, 15.62, and 1000μg/ml, respectively. Rhodomyrtone displayed activity with the MIC values of 0.78 and 0.39μg/ml against S. aureus ATCC 25923 and S. mutans, respectively. The MIC value of the compound against C. albicans ATCC 90028 was more than 100μg/ml which was the highest test concentration. All pathogenic microorganisms treated with the extract and rhodomyrtone at their subinhibitory concentrations resulted in a decrease in their adherence ability to both plastic surface and buccal cells. It is suggested that R. tomentosa extract and rhodomyrtone may be useful in therapy or as prophylaxis in infections involving oral pathogens.
This investigation was aimed at assessing a possible interaction of a traditional Thai herbal rec... more This investigation was aimed at assessing a possible interaction of a traditional Thai herbal recipe, “Ya-Sa-Marn-Phlae (YSMP),” used for wound treatments with topical antiseptics, povidone-iodine (PI) solution and hydrogen peroxide (H2O2), and effects of THR-SK010 alone and the combinations onStaphylococcus aureus. Antibacterial activities of ethanol extracts from the herbal recipe were determined against both methicillin resistantStaphylococcus aureus(MRSA) and methicillin-susceptibleS. aureus(MSSA). YSMP exhibited remarkable antistaphylococcal activity with MIC values of 3.9–7.8 μg/mL. This recipe possessed bacteriostatic activity and did not reduce the tolerance of both MRSA and MSSA isolates to the high ionic strength. Interaction between THR-SK010 and the antiseptics was carried out by checkerboard testing and time-kill assay. Both indifferent and slightly antagonistic effects were observed with THR-SK010/PI and THR-SK010/H2O2combinations against the tested isolates. In additi...
Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA... more Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA) and natural rubber (NR) blends, in the presence of maleic acid as a cross-linking agent were studied. The effect of the maleic acid content, curing temperature, and curing time on the properties of the polymer blend was investigated. Cross-linking between PVA and maleic acid was observed by attenuated total reflection mode–Fourier transform infrared spectroscopy at 1152 cm−1. The swelling ratio of the polymer blend decreased as a function of the increase of the maleic acid content. The tensile strength of the polymer blend increased with an increase of both the maleic acid and the curing time. The highest tensile strength of the samples was observed with 40% w/w maleic acid after a 24 h curing time at 120 °C. The elongation at the break of 60/40 NR/PVA was ∼500% at 120 °C for 1 h. In addition, the polymer blend showed good antibacterial activity with Staphylococcus aureus ATCC25923, Es...
Acetone, ethyl acetate, 95% ethanol and aqueous extracts of Quercus infectoria (Q. infectoria) de... more Acetone, ethyl acetate, 95% ethanol and aqueous extracts of Quercus infectoria (Q. infectoria) demonstrated significant antibacterial activities against all strains of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). Inhibition zones were in the range 11.75-16.82 mm. Both MRSA and MSSA strains exhibited minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values at 0.13 and 0.13-1.00 mg/mL, respectively. At 2 MIC, the growth of two representative MRSA strains was continually inhibited for at least 20 h. Surviving MRSA cells were not detected within 12-14 h after treatment with the extract at 4 MIC concentration. Staphylococcus aureus ATCC 25923 demonstrated similar results.
Increasing rates of infections caused by multidrug resistant Acinetobacter baumannii (MDRAB) and ... more Increasing rates of infections caused by multidrug resistant Acinetobacter baumannii (MDRAB) and extensively drug resistant A. baumannii (XDRAB) have caused the need for searching alternative agents. The purposed of this project was to search plant-derived natural products that act as resistant modifying agents (RMAs) against A. baumannii. In this study, we further evaluated the activity of Holarrhena antidysenterica that has been previously proposed as RMA of novobiocin for a model strain, A. baumannii ATCC 19606 on clinically isolated non-MDRAB, MDRAB, and XDRAB. Effects of H. antidysenterica on outer membrane permeability and efflux pumps of the pathogen were conducted to preliminary elucidate mechanisms of this resistant modifier. Novobiocin was selected as a model antibiotic because it is well-established as an effective agent against Gram-positive pathogens. But, it possessed low level of antibacterial activity against Gram-negative pathogens due to an effective permeability barrier of these pathogens. H. antidysenterica ethanol extract possessed weak intrinsic antibacterial activity with minimum inhibitory concentration (MIC) more than 1000 μg/mL. The extract, at concentrations of 250, 125, and 62.5 μg/mL, remarkably enhanced the inhibitory effects of novobiocin (1/4 × MIC; 1-4 μg/mL) against XDRAB isolates. Synergistic effects of novobiocin at 1/4 × MIC and 1/8 × MIC in combination with H. antidysenterica either at 31.2, 15.6, or 7.8 μg/mL against clinical isolates non-MDRAB, MDRAB, and XDRAB were evidenced for 80% of the combinations (189 out of 234 combinations). Although, no enhancement of the accumulation of ethidium bromide was observed after treated with H. antidysenterica, this plant extract weakened the outer membrane of the pathogen as indicated by an increase in the N-phenyl-1-naphthylamine uptake. Our results suggested that H. antidysenterica which primarily interrupts membrane permeability should be further investigated as a promising resistant modifier for A. baumannii.
The presence of bacterial biofilm, particularly formed by Pseudomonas aeruginosa, has been consid... more The presence of bacterial biofilm, particularly formed by Pseudomonas aeruginosa, has been considered an important factor responsible for wound chronicity. The objective of this study was to investigate the antibiofilm activity of water and ethanol extracts obtained from three traditional herbal recipes (THR-SK004, THR-SK010, and THR-SK011) on biofilm formation and on mature biofilm of a reference strain of P. aeruginosa. The effects of the extracts on the biofilm mass were evaluated by using crystal violet (CV) assay. The respiratory activity of preformed biofilm of P. aeruginosa after treatment with the extract was determined by MTT reduction assay. Scanning electron microscopy was used to furnish images of biofilm reduction after the recipe treatment. Tested ethanol extracts displayed antibiofilm activity, but the water extracts exhibited low biofilm inhibition activity at the tested concentrations. Remarkable reduction in biofilm formation of P. aeruginosa was found after treatment with the THR-SK010 ethanol extract (THR-SK010E). Treatments with this extract resulted in prevention of biofilm formation of P. aeruginosa on both polystyrene and glass surfaces. Almost 50% reduction in the bacterial metabolic activity in the preformed biofilm was seen after exposure to the extract-supplemented buffer for 12 hr. After a 24-hr treatment with THR-SK010E at 62.5 μg/ml, 97.3% of the preformed biofilms were destroyed. Promising antibiofilm activity was displayed by the THR-SK010 ethanol extract, suggesting further investigation to explore the possible utilization of the herbal recipe as an antibiofilm agent, especially for wound treatment.
To establish the effect of Quercus infectoria G. Olivier extract and its main constituent, tannic... more To establish the effect of Quercus infectoria G. Olivier extract and its main constituent, tannic acid, on staphylococcal biofilm and their anti-biofilm mechanisms. Anti-biofilm activity of the plant materials on clinical isolated of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staph. aureus was employed using a crystal violet-stained microtiter plate method. The extract at minimum inhibitory concentration (MIC; 0.25 mg ml(-1)) was significantly reduced the biofilm formation of the isolates (P < 0.05). The effect on staphylococcal cell surface hydrophobicity (CSH) of the test compounds was investigated as a possible mode of action of the anti-biofilm activity. The hydrophobicity index of all the bacterial isolates increased following treatment with supra-MIC, MIC and sub-MIC of the extract and tannic acid. Observation of the treated bacterial cells by electron microscopy revealed that the test compounds caused clumps of partly divided cocci with thickened and slightly rough cell wall. The results indicated that Q. infectoria extract and tannic acid affected staphylococcal biofilm formation and their effect on bacterial CSH and cell wall may involve in the anti-biofilm activity. This evidence highlighted the anti-biofilm potency of the natural products and clarified their anti-biofilm mechanisms.
In traditional Thai medicine, nutgall of Quercus infectoria G. Olivier is well-documented as an e... more In traditional Thai medicine, nutgall of Quercus infectoria G. Olivier is well-documented as an effective agent for wound and skin infections. The present study was aimed to establish modes of action of the ethanol extract of the plant as well as its main constituents to induce anti-methicillin-resistant Staphylococcus aureus (MRSA) activity. The minimal inhibitory concentration (MIC)/minimal bactericidal concentration (MBC) values of ethyl acetate I, ethyl acetate II, 95% ethanol and 30% ethanol fractions against MRSA were 0.06/0.25, 0.13/0.25, 0.25/0.5 and 0.5/1.00 mg ml(-1), respectively. Ellagic acid, gallic acid, syringic acid and tannic acid as major components of Q. infectoria nutgall extract were included in this study. Among these, gallic acid and tannic acid demonstrated good MIC/MBC values at 0.06/0.06 and 0.13/0.25 mg ml(-1), respectively. A lysis experiment demonstrated that the ethanol extract, ethyl acetate fraction I and all of the main components failed to lyse MRSA cells. In contrast, both MRSA and Staph. aureus ATCC 25923 treated with the ethanol extract, ethyl acetate fraction I, gallic acid and tannic acid displayed significant loss of tolerance to low osmotic pressure and high salt concentration. The results documented the effect of different fractions of Q. infectoria and purified compounds on MRSA and Staph. aureus. In addition, the study demonstrated that treatment with Q. infectoria extract and the purified compounds results in hypersensitivity to low and high osmotic pressure. This study provides scientific information to support the traditional uses of the nutgall extract and suggesting its anti-MRSA mechanisms.
The Journal of Alternative and Complementary Medicine, 2013
This present work was aimed to investigate wound healing-related biologic activities of tradition... more This present work was aimed to investigate wound healing-related biologic activities of traditional herbal formulas used for wound treatment in southern Thailand. Water and ethanol extracts of the formulas (THR-SK004, THR-SK010, and THR-SK011) were tested for their antibacterial potency against methicillin-resistant Staphylococcus aureus (MRSA) and -susceptible S. aureus. Anti-inflammatory activities of the extracts were assessed by detection of the inhibition of lipopolysaccharide-induced nitric oxide production. Anti-oxidant activities and cytotoxicity of the extracts were also measured. Among the tested formulas, ethanol extract of THR-SK010 consisting of four herbs: Curcuma longa L., Areca catechu L., Oryza sativa L., and Garcinia mangostana L., was found to possess promising antibacterial activities with MIC90 of 4 μg mL(-1) against MRSA isolates. This ethanol extract offered the highest anti-inflammatory activity as well as DPPH and hydroxyl radical scavenging activities. Remarkable antibacterial, anti-inflammatory, and antioxidant activities as well as low toxicity on Vero cells of THR-SK010 ethanol extract provide scientific information to support the topical use of the formula for wound treatment. This information proposes the potential to develop a new generation of phytopharmaceuticals based on traditional knowledge.
ABSTRACT Introduction The present work aimed to evaluate the antibacterial activity, phytochemica... more ABSTRACT Introduction The present work aimed to evaluate the antibacterial activity, phytochemical constituents, and cytotoxic effect of plant based remedies which are traditionally used for the treatment of infections. Methodology: Antibacterial activity of the ethanol extracts of plant based preparations described in Thai Pharmaceutical Textbook namely: Tri-Khan-Tha-Wart, Tri-Ke-Son-Phet, Tri-Phit-Tha-Chak, Tri-Ka-Tuk, Tri-Pha-La, Tri-Kan-La-Phit, Tri-Chin-Tha-La-Ma-Ka, Tri-San, Tri-Sa-Mo, and Tri-Ke-Son-Mat were evaluated on 20 isolates of Gram-positive and Gram-negative pathogens. Qualitative phytochemical analysis and cytotoxic effect on on Vero cells of the extracts were additionally performed. Results The extract of Tri-Chin-Tha-La-Ma-Ka possessed the highest and most significant antibacterial activity with minimum inhibitory concentration (MIC) values of <16 μg/mL against methicillin resistant Staphylococcus aureus (MRSA), a biofilm-producing Staphylococcus epidermidis, acne lesion isolated coagulase-positive and coagulase-negative staphylococci isolates. Our preliminary phytochemical test revealed that triterpenoids and phenolics were common components found in all tested preparations. Most of the tested remedies had IC50 > 50 μg/mL on Vero cells, whereas Tri-Chin-Tha-La-Ma-Ka, Tri-Ka-Tuk, and Tri-Kan-La-Phit had IC50 value of 0.9, 48.8, and 28.9 μg/mL, respectively. Conclusion These findings suggest that Tri-Chin-Tha-La-Ma-Ka could be further studied as a promising antibacterial agent. Investigations on other biological activities related to its traditional applications, appropriate biomarkers, and treatment mechanisms of the preparation are required
Emergence and spread of antibiotic-resistant Acinetobacter baumannii have become a major public h... more Emergence and spread of antibiotic-resistant Acinetobacter baumannii have become a major public health concern. This study was designed to investigate the efficacy of Holarrhena antidysenterica extract and its major steroidal alkaloid conessine as resistance-modifying agents (RMAs) on the susceptibility of A. baumannii to novobiocin and rifampicin. A significant synergistic activity of both the extract and conessine in combination with either novobiocin or rifampicin with fractional inhibitory concentration index ≤0.5 was demonstrated. Fluorescent dyes and different efflux pump inhibitors were used to further investigate the synergism. Increase in the uptake of 1-N-phenylnaphthylamine in the bacterial cells treated with the extract and conessine was not observed indicating that both substances did not act as permeabilizers. With regard to efflux pump inhibition, no accumulation in ethidium bromide (EtBr) was noticed suggesting that the AdeABC pump was not involved. In contrast, accumulation in Pyronin Y was significantly increased (p < 0.05) demonstrating that the synergism was due to interference with the AdeIJK pump. Study on frequencies of the spontaneous mutational resistance to the extract in combination with antibiotics demonstrated attenuation in drug-resistant organisms. Thus, H. antidysenterica extract and conessine as RMAs may offer a combinatory therapy to restore antibiotic susceptibility in the extensively drug-resistant A. baumannii.
The Journal of Alternative and Complementary Medicine, 2014
Household ancient remedies reported here are described in the National List of Essential Medicine... more Household ancient remedies reported here are described in the National List of Essential Medicines and have traditionally been used in Thailand to treat infection-related ailments. However, the safety and effectiveness of these remedies have been poorly evaluated. The aim of this study was to evaluate the antibacterial properties of these remedies against seven gram-positive and gram-negative multidrug-resistant bacteria species. Phytochemical constituents and cytotoxicity of these remedies were also determined. Seven remedies, consisting of Um-Ma-Luk-Ka-Wa-Tee, Chan-Ta-Lee-La, Kheaw-Hom, Learng-Pid-Sa-Mud, Pra-Sa-Chan-Dang, Dhart-Ban-Chob, and Tree-Hom, were prepared by a licensed traditional medical doctor using a mixture of medicinal plants. Antibacterial activity of ethanol extracts of the remedies was determined by using a broth microdilution method. Qualitative phytochemical screening analysis was carried out to identify the presence of major components. Cytotoxicity activities of the extracts against Vero cells were assessed by green fluorescent protein-based assay. With the exception of Dhart-Ban-Chob extract, significant minimum inhibitory concentrations (MICs) of <16 to 32 μg/mL were observed for the remedy extracts depending on the bacterial strains. The Um-Ma-Luk-Ka-Wa-Tee extract was noncytotoxic against Vero cells and possessed the highest activity, with MICs of <16 to 31 μg/mL against all methicillin-resistant Staphylococcus aureus isolates. Remarkable antibacterial activities against multidrug-resistant pathogens, as well as low toxicity on Vero cells, of Um-Ma-Luk-Ka-Wa-Tee support the use of this remedy in traditional medicine. Further investigation on other biological activities related to traditional applications, appropriate biomarkers, and treatment mechanisms of the household remedy are required.
The adherence of oral pathogenic microorganisms to host tissues is the initial step for successfu... more The adherence of oral pathogenic microorganisms to host tissues is the initial step for successful process of oral diseases. This study aimed to determine the effect of the Rhodomyrtus tomentosa leaf extract and rhodomyrtone, an antibacterial compound from R. tomentosa leaf, on adhesion of some oral pathogens to polystyrene plastic surface and human buccal epithelial cells. The minimum inhibitory concentration (MIC) was evaluated using broth microdilution method. The microbial adhesion to the plastic surface and buccal cells was determined using microtiter plate method and microscopy technique. The ethanol extract of leaf demonstrated antibacterial activity against oral microorganisms including Staphylococcus aureus ATCC 25923, Streptococcus mutans (clinical isolate), and Candida albicans ATCC 90028 with the MIC values of 31.25, 15.62, and 1000μg/ml, respectively. Rhodomyrtone displayed activity with the MIC values of 0.78 and 0.39μg/ml against S. aureus ATCC 25923 and S. mutans, respectively. The MIC value of the compound against C. albicans ATCC 90028 was more than 100μg/ml which was the highest test concentration. All pathogenic microorganisms treated with the extract and rhodomyrtone at their subinhibitory concentrations resulted in a decrease in their adherence ability to both plastic surface and buccal cells. It is suggested that R. tomentosa extract and rhodomyrtone may be useful in therapy or as prophylaxis in infections involving oral pathogens.
This investigation was aimed at assessing a possible interaction of a traditional Thai herbal rec... more This investigation was aimed at assessing a possible interaction of a traditional Thai herbal recipe, “Ya-Sa-Marn-Phlae (YSMP),” used for wound treatments with topical antiseptics, povidone-iodine (PI) solution and hydrogen peroxide (H2O2), and effects of THR-SK010 alone and the combinations onStaphylococcus aureus. Antibacterial activities of ethanol extracts from the herbal recipe were determined against both methicillin resistantStaphylococcus aureus(MRSA) and methicillin-susceptibleS. aureus(MSSA). YSMP exhibited remarkable antistaphylococcal activity with MIC values of 3.9–7.8 μg/mL. This recipe possessed bacteriostatic activity and did not reduce the tolerance of both MRSA and MSSA isolates to the high ionic strength. Interaction between THR-SK010 and the antiseptics was carried out by checkerboard testing and time-kill assay. Both indifferent and slightly antagonistic effects were observed with THR-SK010/PI and THR-SK010/H2O2combinations against the tested isolates. In additi...
Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA... more Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA) and natural rubber (NR) blends, in the presence of maleic acid as a cross-linking agent were studied. The effect of the maleic acid content, curing temperature, and curing time on the properties of the polymer blend was investigated. Cross-linking between PVA and maleic acid was observed by attenuated total reflection mode–Fourier transform infrared spectroscopy at 1152 cm−1. The swelling ratio of the polymer blend decreased as a function of the increase of the maleic acid content. The tensile strength of the polymer blend increased with an increase of both the maleic acid and the curing time. The highest tensile strength of the samples was observed with 40% w/w maleic acid after a 24 h curing time at 120 °C. The elongation at the break of 60/40 NR/PVA was ∼500% at 120 °C for 1 h. In addition, the polymer blend showed good antibacterial activity with Staphylococcus aureus ATCC25923, Es...
Acetone, ethyl acetate, 95% ethanol and aqueous extracts of Quercus infectoria (Q. infectoria) de... more Acetone, ethyl acetate, 95% ethanol and aqueous extracts of Quercus infectoria (Q. infectoria) demonstrated significant antibacterial activities against all strains of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA). Inhibition zones were in the range 11.75-16.82 mm. Both MRSA and MSSA strains exhibited minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values at 0.13 and 0.13-1.00 mg/mL, respectively. At 2 MIC, the growth of two representative MRSA strains was continually inhibited for at least 20 h. Surviving MRSA cells were not detected within 12-14 h after treatment with the extract at 4 MIC concentration. Staphylococcus aureus ATCC 25923 demonstrated similar results.
Increasing rates of infections caused by multidrug resistant Acinetobacter baumannii (MDRAB) and ... more Increasing rates of infections caused by multidrug resistant Acinetobacter baumannii (MDRAB) and extensively drug resistant A. baumannii (XDRAB) have caused the need for searching alternative agents. The purposed of this project was to search plant-derived natural products that act as resistant modifying agents (RMAs) against A. baumannii. In this study, we further evaluated the activity of Holarrhena antidysenterica that has been previously proposed as RMA of novobiocin for a model strain, A. baumannii ATCC 19606 on clinically isolated non-MDRAB, MDRAB, and XDRAB. Effects of H. antidysenterica on outer membrane permeability and efflux pumps of the pathogen were conducted to preliminary elucidate mechanisms of this resistant modifier. Novobiocin was selected as a model antibiotic because it is well-established as an effective agent against Gram-positive pathogens. But, it possessed low level of antibacterial activity against Gram-negative pathogens due to an effective permeability barrier of these pathogens. H. antidysenterica ethanol extract possessed weak intrinsic antibacterial activity with minimum inhibitory concentration (MIC) more than 1000 μg/mL. The extract, at concentrations of 250, 125, and 62.5 μg/mL, remarkably enhanced the inhibitory effects of novobiocin (1/4 × MIC; 1-4 μg/mL) against XDRAB isolates. Synergistic effects of novobiocin at 1/4 × MIC and 1/8 × MIC in combination with H. antidysenterica either at 31.2, 15.6, or 7.8 μg/mL against clinical isolates non-MDRAB, MDRAB, and XDRAB were evidenced for 80% of the combinations (189 out of 234 combinations). Although, no enhancement of the accumulation of ethidium bromide was observed after treated with H. antidysenterica, this plant extract weakened the outer membrane of the pathogen as indicated by an increase in the N-phenyl-1-naphthylamine uptake. Our results suggested that H. antidysenterica which primarily interrupts membrane permeability should be further investigated as a promising resistant modifier for A. baumannii.
The presence of bacterial biofilm, particularly formed by Pseudomonas aeruginosa, has been consid... more The presence of bacterial biofilm, particularly formed by Pseudomonas aeruginosa, has been considered an important factor responsible for wound chronicity. The objective of this study was to investigate the antibiofilm activity of water and ethanol extracts obtained from three traditional herbal recipes (THR-SK004, THR-SK010, and THR-SK011) on biofilm formation and on mature biofilm of a reference strain of P. aeruginosa. The effects of the extracts on the biofilm mass were evaluated by using crystal violet (CV) assay. The respiratory activity of preformed biofilm of P. aeruginosa after treatment with the extract was determined by MTT reduction assay. Scanning electron microscopy was used to furnish images of biofilm reduction after the recipe treatment. Tested ethanol extracts displayed antibiofilm activity, but the water extracts exhibited low biofilm inhibition activity at the tested concentrations. Remarkable reduction in biofilm formation of P. aeruginosa was found after treatment with the THR-SK010 ethanol extract (THR-SK010E). Treatments with this extract resulted in prevention of biofilm formation of P. aeruginosa on both polystyrene and glass surfaces. Almost 50% reduction in the bacterial metabolic activity in the preformed biofilm was seen after exposure to the extract-supplemented buffer for 12 hr. After a 24-hr treatment with THR-SK010E at 62.5 μg/ml, 97.3% of the preformed biofilms were destroyed. Promising antibiofilm activity was displayed by the THR-SK010 ethanol extract, suggesting further investigation to explore the possible utilization of the herbal recipe as an antibiofilm agent, especially for wound treatment.
To establish the effect of Quercus infectoria G. Olivier extract and its main constituent, tannic... more To establish the effect of Quercus infectoria G. Olivier extract and its main constituent, tannic acid, on staphylococcal biofilm and their anti-biofilm mechanisms. Anti-biofilm activity of the plant materials on clinical isolated of methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staph. aureus was employed using a crystal violet-stained microtiter plate method. The extract at minimum inhibitory concentration (MIC; 0.25 mg ml(-1)) was significantly reduced the biofilm formation of the isolates (P < 0.05). The effect on staphylococcal cell surface hydrophobicity (CSH) of the test compounds was investigated as a possible mode of action of the anti-biofilm activity. The hydrophobicity index of all the bacterial isolates increased following treatment with supra-MIC, MIC and sub-MIC of the extract and tannic acid. Observation of the treated bacterial cells by electron microscopy revealed that the test compounds caused clumps of partly divided cocci with thickened and slightly rough cell wall. The results indicated that Q. infectoria extract and tannic acid affected staphylococcal biofilm formation and their effect on bacterial CSH and cell wall may involve in the anti-biofilm activity. This evidence highlighted the anti-biofilm potency of the natural products and clarified their anti-biofilm mechanisms.
In traditional Thai medicine, nutgall of Quercus infectoria G. Olivier is well-documented as an e... more In traditional Thai medicine, nutgall of Quercus infectoria G. Olivier is well-documented as an effective agent for wound and skin infections. The present study was aimed to establish modes of action of the ethanol extract of the plant as well as its main constituents to induce anti-methicillin-resistant Staphylococcus aureus (MRSA) activity. The minimal inhibitory concentration (MIC)/minimal bactericidal concentration (MBC) values of ethyl acetate I, ethyl acetate II, 95% ethanol and 30% ethanol fractions against MRSA were 0.06/0.25, 0.13/0.25, 0.25/0.5 and 0.5/1.00 mg ml(-1), respectively. Ellagic acid, gallic acid, syringic acid and tannic acid as major components of Q. infectoria nutgall extract were included in this study. Among these, gallic acid and tannic acid demonstrated good MIC/MBC values at 0.06/0.06 and 0.13/0.25 mg ml(-1), respectively. A lysis experiment demonstrated that the ethanol extract, ethyl acetate fraction I and all of the main components failed to lyse MRSA cells. In contrast, both MRSA and Staph. aureus ATCC 25923 treated with the ethanol extract, ethyl acetate fraction I, gallic acid and tannic acid displayed significant loss of tolerance to low osmotic pressure and high salt concentration. The results documented the effect of different fractions of Q. infectoria and purified compounds on MRSA and Staph. aureus. In addition, the study demonstrated that treatment with Q. infectoria extract and the purified compounds results in hypersensitivity to low and high osmotic pressure. This study provides scientific information to support the traditional uses of the nutgall extract and suggesting its anti-MRSA mechanisms.
The Journal of Alternative and Complementary Medicine, 2013
This present work was aimed to investigate wound healing-related biologic activities of tradition... more This present work was aimed to investigate wound healing-related biologic activities of traditional herbal formulas used for wound treatment in southern Thailand. Water and ethanol extracts of the formulas (THR-SK004, THR-SK010, and THR-SK011) were tested for their antibacterial potency against methicillin-resistant Staphylococcus aureus (MRSA) and -susceptible S. aureus. Anti-inflammatory activities of the extracts were assessed by detection of the inhibition of lipopolysaccharide-induced nitric oxide production. Anti-oxidant activities and cytotoxicity of the extracts were also measured. Among the tested formulas, ethanol extract of THR-SK010 consisting of four herbs: Curcuma longa L., Areca catechu L., Oryza sativa L., and Garcinia mangostana L., was found to possess promising antibacterial activities with MIC90 of 4 μg mL(-1) against MRSA isolates. This ethanol extract offered the highest anti-inflammatory activity as well as DPPH and hydroxyl radical scavenging activities. Remarkable antibacterial, anti-inflammatory, and antioxidant activities as well as low toxicity on Vero cells of THR-SK010 ethanol extract provide scientific information to support the topical use of the formula for wound treatment. This information proposes the potential to develop a new generation of phytopharmaceuticals based on traditional knowledge.
ABSTRACT Introduction The present work aimed to evaluate the antibacterial activity, phytochemica... more ABSTRACT Introduction The present work aimed to evaluate the antibacterial activity, phytochemical constituents, and cytotoxic effect of plant based remedies which are traditionally used for the treatment of infections. Methodology: Antibacterial activity of the ethanol extracts of plant based preparations described in Thai Pharmaceutical Textbook namely: Tri-Khan-Tha-Wart, Tri-Ke-Son-Phet, Tri-Phit-Tha-Chak, Tri-Ka-Tuk, Tri-Pha-La, Tri-Kan-La-Phit, Tri-Chin-Tha-La-Ma-Ka, Tri-San, Tri-Sa-Mo, and Tri-Ke-Son-Mat were evaluated on 20 isolates of Gram-positive and Gram-negative pathogens. Qualitative phytochemical analysis and cytotoxic effect on on Vero cells of the extracts were additionally performed. Results The extract of Tri-Chin-Tha-La-Ma-Ka possessed the highest and most significant antibacterial activity with minimum inhibitory concentration (MIC) values of <16 μg/mL against methicillin resistant Staphylococcus aureus (MRSA), a biofilm-producing Staphylococcus epidermidis, acne lesion isolated coagulase-positive and coagulase-negative staphylococci isolates. Our preliminary phytochemical test revealed that triterpenoids and phenolics were common components found in all tested preparations. Most of the tested remedies had IC50 > 50 μg/mL on Vero cells, whereas Tri-Chin-Tha-La-Ma-Ka, Tri-Ka-Tuk, and Tri-Kan-La-Phit had IC50 value of 0.9, 48.8, and 28.9 μg/mL, respectively. Conclusion These findings suggest that Tri-Chin-Tha-La-Ma-Ka could be further studied as a promising antibacterial agent. Investigations on other biological activities related to its traditional applications, appropriate biomarkers, and treatment mechanisms of the preparation are required
Emergence and spread of antibiotic-resistant Acinetobacter baumannii have become a major public h... more Emergence and spread of antibiotic-resistant Acinetobacter baumannii have become a major public health concern. This study was designed to investigate the efficacy of Holarrhena antidysenterica extract and its major steroidal alkaloid conessine as resistance-modifying agents (RMAs) on the susceptibility of A. baumannii to novobiocin and rifampicin. A significant synergistic activity of both the extract and conessine in combination with either novobiocin or rifampicin with fractional inhibitory concentration index ≤0.5 was demonstrated. Fluorescent dyes and different efflux pump inhibitors were used to further investigate the synergism. Increase in the uptake of 1-N-phenylnaphthylamine in the bacterial cells treated with the extract and conessine was not observed indicating that both substances did not act as permeabilizers. With regard to efflux pump inhibition, no accumulation in ethidium bromide (EtBr) was noticed suggesting that the AdeABC pump was not involved. In contrast, accumulation in Pyronin Y was significantly increased (p < 0.05) demonstrating that the synergism was due to interference with the AdeIJK pump. Study on frequencies of the spontaneous mutational resistance to the extract in combination with antibiotics demonstrated attenuation in drug-resistant organisms. Thus, H. antidysenterica extract and conessine as RMAs may offer a combinatory therapy to restore antibiotic susceptibility in the extensively drug-resistant A. baumannii.
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