Preparation of Self-Assembled, Curcumin-Loaded Nano-Micelles Using Quarternized Chitosan-Vanillin Imine (QCS-Vani Imine) Conjugate and Evaluation of Synergistic Anticancer Effect with Cisplatin.

Nano-micelles are self-assembling colloidal dispersions applied to enhance the anticancer efficacy of chemotherapeutic agents. In this study, the conjugate of quarternized chitosan and vanillin imine (QCS-Vani imine) was synthesized using the reaction of a Schiff base characterized by proton-NMR (1HNMR), UV-Vis spectroscopy, and FT-IR. The critical micelle concentration (CMC), particle size, and zeta potential of the resulting product were determined. The QCS-Vani imine conjugate was used as a carrier for the development of curcumin-loaded nano-micelles, and their entrapment efficiency (%EE), drug-loading capacity (%LC) and in vitro release were investigated using HPLC analysis. Moreover, the nano-micelles containing curcumin were combined with various concentrations of cisplatin and evaluated for a possible anticancer synergistic effect. The anticancer activity was evaluated against lung cancer A549 and mouse fibroblast L929 cell lines. The percent yield (%) of the QCS-Vani imine conjugate was 93.18%. The curcumin-loaded QCS-Vani imine nano-micelles were characterized and found to have a spherical shape (by TEM) with size < 200 nm (by DLS) with high %EE up to 67.61% and %LC up to 6.15 ± 0.41%. The loaded lyophilized powder of the nano-micelles was more stable at 4 °C than at room temperature during 120 days of storage. pH-sensitive release properties were observed to have a higher curcumin release at pH 5.5 (cancer environment) than at pH 7.4 (systemic environment). Curcumin-loaded QCS-Vani imine nano-micelles showed higher cytotoxicity and selectivity toward lung cancer A549 cell lines and exhibited lower toxicity toward the normal cell (H9C2) than pure curcumin. Moreover, the curcumin-loaded QCS-Vani imine nano-micelles exhibited an enhanced property of inducing cell cycle arrest during the S-phase against A549 cells and showed prominently induced apoptosis in lung cancer cells compared to that with curcumin. The co-treatment of cisplatin with curcumin-loaded QCS-Vani imine nano-micelles presented an enhanced anticancer effect, showing 8.66 ± 0.88 µM as the IC50 value, in comparison to the treatment with cisplatin alone (14.22 ± 1.01 µM). These findings suggest that the developed QCS-Vani imine nano-micelle is a potential drug delivery system and could be a promising approach for treating lung cancer in combination with cisplatin.

Nanocomplex of quaternized cyclodextrin grafted chitosan and hyaluronic acid for a skin delivery.

Water soluble quaternized cyclodexrin grafted chitosan (QCD-g-CS) was synthesized by combining both beneficial properties of ß-cyclodextrin (ß-CD) and the chitosan (CS) backbone. The chitosan backbone exhibits positive charges, while the ß-CD moieties are available to include hydrophobic guest molecules into the cavity. The present work demonstrates a formation of nanocomplexes by simple mixing of the cationic QCD-g-CS with three different molecular weights of anionic Hyaluronic acid (low, medium and high HA; LHA, MHA and HHA, respectively). The HA is well-known on providing hydration to the skin and normalize keratinization. However, its strong hydrophilicity limits skin absorption. The polyelectrolyte nanocomplexes between QCD-g-CS and HA formed through the electrostatic interactions were confirmed by FTIR. Particle size of HA nanocomplexes were greater than that of free QCD-g-CS and increased with an increase in HA content. The complex of LHA and MHA improve the water retention capacity as well as ability to control the release of HA to be slower than the original HA. The release of both LHA and MHA from their complexes were both limited diffusion kinetics. Pronounced effect of small particle sizes of LHA complexes was found to benefit skin penetration. Clinical study indicated that LHA complexes improved skin texture and elasticity due to an increase in skin hydration. It is suggested that the QCD-g-CS in combination with anionic hydrophilic HA can be used as a promising polysaccharide-based skin delivery system.

Active targeting liposome-PLGA composite for cisplatin delivery against cervical cancer.

Cisplatin (Cis) is a widely used chemotherapeutic drug for cancer treatment. However, toxicities and drug resistance limit the use of cisplatin. This study was aimed to improve cisplatin delivery using a targeting strategy to reduce the toxicity. In the present study, combinations of poly lactic-co-glycolic acids (PLGA) and liposomes were used as carriers for cisplatin delivery. In addition, to target the nanoparticle towards tumor cells, the liposome was conjugated with Avastin®, an anti-VEGF antibody. Cisplatin was loaded into PLGA using the double emulsion solvent evaporation method and further encapsulated in an Avastin® conjugated liposome (define herein as L-PLGA-Cis-Avastin®). Their physicochemical properties, including particle size, ζ-potential, encapsulation efficiency and drug release profiles were characterized. In addition, a study of the efficiency of tumor targeted drug delivery was conducted with cervical tumor bearing mice via intravenous injection. The therapeutic effect was examined in a 3D spheroid of SiHa cell line and SiHa cells bearing mice. The L-PLGA-Cis-Avastin® prompted a significant effect on cell viability and triggered cytotoxicity of SiHa cells. A cell internalization study confirmed that the L-PLGA-Cis-Avastin® had greater binding specificity to SiHa cells than those of L-PLGA-Cis or free drug, resulting in enhanced cellular uptake. Tumor targeting specificity was finally confirmed in xenograft tumors. Taken together, this nanoparticle could serve as a promising specific targeted drug for cervical cancer treatment.

Enhanced efficacy of immersion vaccination in tilapia against columnaris disease by chitosan-coated "pathogen-like" mucoadhesive nanovaccines.

Red tilapia (Oreochromis sp.) has become one of the most important fish in aquaculture. Bacterial infection caused by Flavobacterium columnare, the causative agent of columnaris disease, has been now identified as one of the most serious infectious diseases in farmed red tilapia and cause major financial damage to the producers. Among the effective prevention and control strategies, vaccination is one of the most effective approach. As the surface of living fish is covered by mucus and directly associated with the mucosal immunity, we therefore hypothesized that better adsorption on mucosal surfaces and more efficient vaccine efficacy could be enhanced biomimetic nanoparticles mimicking the mucoadhesive characteristic of live F. columnare. In this work, we describe an effective approach to targeted antigen delivery by coating the surface of nanoparticles with mucoadhesive chitosan biopolymer to provide "pathogen-like" properties that ensure nanoparticles binding on fish mucosal membrane. The physiochemical properties of nanovaccines were analyzed, and their mucoadhesive characteristics and immune response against pathogens were also evaluated. The prepared vaccines were nano-sized and spherical as confirmed by scanning electron microscope (SEM). The analysis of hydrodynamic diameter and zeta-potential also suggested the successful modification of nanovaccines by chitosan as indicated by positively charged and the overall increased diameter of chitosan-modified nanovaccines. In vivo mucoadhesive study demonstrated the excellent affinity of the chitosan-modified nanovaccines toward fish gills as confirmed by bioluminescence imaging, fluorescent microscopy, and spectrophotometric quantitative measurement. Following vaccination with the prepared nanovaccines by immersion 30 min, the challenge test was then carried out 30 and 60 days post-vaccination and resulted in high mortalities in the control. The relative percent survival (RPS) of vaccinated fish was greater than 60% for mucoadhesive nanovaccine. Our results also suggested that whole-cell vaccines failed to protect fish from columnaris infection, which is consistent with the mucoadhesive assays showing that whole-cell bacteria were unable to bind to mucosal surfaces. In conclusion, we could use this system to deliver antigen preparation to the mucosal membrane of tilapia and obtained a significant increase in survival compared to controls, suggesting that targeting mucoadhesive nanovaccines to the mucosal surface could be exploited as an effective method for immersion vaccination.

The potential of mucoadhesive polymer in enhancing efficacy of direct immersion vaccination against Flavobacterium columnare infection in tilapia.

Vaccination is the most effective approach for prevention of infectious diseases in aquaculture. Although immersion vaccination is more applicable compared to in-feed/oral administration and injection, this method suffers from low potency as the efficiency of uptake of antigens through mucosal membranes is limited. In this study, we have successfully developed a mucoadhesive vaccine delivery system to enhance the efficacy of direct immersion vaccination against Flavobacterium columnare, the causative agent of columnaris disease in red tilapia. A formalin-killed negatively charged, bacterial cell suspension was used to prepare a mucoadhesive vaccine by electrostatic coating with positively charged chitosan. Our results demonstrate that the chitosan-complexed vaccine greatly increases its mucoadhesiveness, thus increasing the chances of vaccine uptake by the gill mucosa and improving the protection obtained against columnaris infection. The surface charge of the chitosan-complexed vaccine was altered from anionic to cationic after chitosan modification. Tilapia were vaccinated with the prepared chitosan-complexed vaccine by immersion. The challenge test was then carried out 30 and 60 days post vaccination, which resulted in a high level of mortalities in the non-vaccinated and uncomplexed vaccine groups. A high relative percentage survival (RPS) of vaccinated fish was noted with the mucoadhesive vaccine. Our results indicated that the naked vaccine failed to protect the fish from columnaris infection, which is consistent with the mucoadhesive assays performed during the study showing that the naked vaccine was unable to bind to mucosal surfaces. This system is therefore an effective method for immersion vaccination in order to deliver the antigen preparation to the mucosal surface membrane of the fish.

Formulation, physical, in vitro and ex vivo evaluation of nanomedicine-based chemosterilant for non-surgical castration of male animals.

The overpopulation of free-roaming companion animals has become the global crisis. The development and application of a suitable, effective, non-surgical approach for animal sterilization would have an enormous advantage over the current surgical method. The main purpose of this study was to develop and evaluate a novel nanomedicine-based chemosterilant for non-surgical castration of male companion animals. In this study, we first sought to investigate the testicular toxicity of different apoptosis-inducing agents. We next synthesized and characterized nano-sized particles which encapsulated the most potent testicular toxicants and evaluated in vitro sterilant properties. Our result showed that doxorubicin exhibited the highest cytotoxic activity against mouse spermatogenic cells. We therefore synthesized and characterized doxorubicin-encapsulated nanoemulsion. The negatively charged particle of doxorubicin-encapsulated nanoemulsion exhibited the anti-proliferative activity towards spermatogetic cells. Apoptosis studies revealed activation of Caspases 3 and 7 as well as annexin V expression. In addition, doxorubicin-encapsulated nanoemulsion exhibited anti-inflammatory activity in lipopolysaccharide-stimulated macrophages. Cell death was observed following treatment of isolated and cultured rat seminiferous tubules with doxorubicin-encapsulated nanoemulsion. In conclusion, nanoemulsion can be a potential carrier for prolonged release and to enhance activity of doxorubicin that may have utility in non-surgical castration of male animals.

Controllable encapsulation of α-mangostin with quaternized ß-cyclodextrin grafted chitosan using high shear mixing.

In this study, the inclusion complex formation between α-mangostin and water-soluble quaternized ß-CD grafted-chitosan (QCD-g-CS) was investigated. Inclusion complex formation with encapsulation efficiency (%EE) of 5, 15 and 75% can be varied using high speed homogenizer. Tuning %EE plays a role on physicochemical and biological properties of α-mangostin/QCD-g-CS complex. Molecular dynamics simulations indicate that α-mangostin is included within the hydrophobic ß-CD cavity and being absorbed on the QCD-g-CS surface, with these results being confirmed by Fourier transform infrared (FTIR) spectroscopy. Probing the release characteristics of the inclusion complex at various %EE (5%, 15% and 75%) in simulated saliva (pH 6.8) demonstrated that α-mangostin release rates were dependent on % EE (order 5% > 15% > 75%). Additionally, higher antimicrobial and anti-inflammation activities were observed for the inclusion complex than those of free α-mangostin due to enhance the solubility of α-mangostin through the inclusion complex with QCD-g-CS.

Efficiency of resveratrol-loaded sericin nanoparticles: Promising bionanocarriers for drug delivery.

Sericin protein nanoparticles are a biocompatible, bio-viable class of nanocarriers gaining prominence in drug delivery system. This research aimed to investigate the suitability fabrication of silk protein (SP) nanoparticles for loading with resveratrol (RSV) via a solventless precipitation technique. The addition of 0.5% (w/v) pluronic surfactant proved optimal for SP nanoparticle fabrication, with obtained nanoparticles being spherical, mono-dispersed and having mean size of approximately 200-400 nm. All exhibited negative surface charges, the extent of which being dependent on the SP concentration, and were non-toxic to normal skin fibroblasts (CRL-2522). Loading of RSV, a promising which poorly soluble multi-targeted anti-oxidative and anti-inflammatory natural polyphenol, into SP nanoparticles proved feasible, with encapsulation levels of 71-75% for 0.6% and 1.0% (w/v) nanoparticle formulations, respectively. Resveratrol-loaded SP nanoparticles strongly inhibited growth of colorectal adenocarcinoma (Caco-2) cells although proved non-cytotoxic to skin fibroblasts, as indicated by cell viability assays. Cellular internalization of SP nanoparticles proved facile and dependent on incubation time; transfection of these carriers, in vitro results indicating sustained release of RSV (over 72 h), and drug solubility enhancements on encapsulation highlight their potential in therapeutic and pharmaceutical applications. Thus, SP nanoparticles is a promising approach to be potential bio-nanocarrier for drug delivery system.

Nanocarrier-mediated delivery of α-mangostin for non-surgical castration of male animals.

The overpopulation of abandoned and stray companion animals has become a global crisis. The main purpose of this study was to develop a novel nanomedicine-based antifertility compound for non-surgical castration of male animals. Mangosteen (Garcinia mangostana L) pericarp extract has been shown to exhibit anti-fertility property. α-mangostin (AM)-loaded nanostructured lipid carrier (AM-NLC) was developed to improve male germ cell apoptosis. This study was conducted to investigate physicochemical properties of AM-NLC and determine the biological effects of AM-NLC on spermatogonia cells and testicular explants obtained from castrated testes. AM-NLC was produced through a hot homogenization technique. The negatively charged particle of AM-NLC was nano-sized with a narrow dispersity. AM-NLC exhibited antiproliferative activity towards spermatogonium cells. It induced apoptosis in the cells. In addition, AM-NLC exhibited anti-inflammatory activities in lipopolysaccharide-activated macrophages. Abnormal anatomy of seminiferous tubule was noted following treatment of testicular explant with AM-NLC. This nanomedicine-based sterilant would be a promising platform that may have utility in non-surgical castration of male animals by intra-testicular injection.

Surface modification of nanostructure lipid carrier (NLC) by oleoyl-quaternized-chitosan as a mucoadhesive nanocarrier.

A nanostructure lipid carrier (NLC) composed of solid, and liquid lipid as a core has been developed as a delivery system for hydrophobic drug molecules. The aim of this research was to fabricate an oleoyl-quaternized-chitosan (CS)-coated NLC, where the mucoadhesive property of nanoparticles is enhanced for more efficient drug delivery. NLC loaded with alpha-mangostin (AP), a model hydrophobic drug, were fabricated using a high pressure homogenization process and subsequently coated with CS. The fabricated nanoparticles showed particle sizes in the range of 200-400nm, with low polydispersity, high physical stability and excellent encapsulation efficiency (EE>90%). Additionally, in vitro viability, cytotoxicity and ability of NLC and CS-NLC to affect apoptosis in carcinoma Caco-2 cells were determined using the Triplex assay. Gene expressiom analysis were performed using quantitative reverse transcription Polymerase Chain Reaction (RT-qPCR). Moreover, in vivo toxicological testing of NLCs was conducted in zebrafish embryos. Results indicated that CS-NLC provieded high cytotoxicity than NLC itself. In the case of AP loaded nanoparticles, NLC loaded with AP (AP-NLC), and CS-NLC loaded with AP (CS-AP-NLC) exhibited higher cytotoxicity to Caco-2 over Hela cells. These results indicate that CS-NLC shows enhanced cellular uptake but increased cytotoxicity characteristics over NLC and therefore careful optimization of dosage and loading levels in CS-NLC is needed to allow cancer cell targeting, and for exploiting the potential of these systems in cancer therapy.

Physical and biological characterization of sericin-loaded copolymer liposomes stabilized by polyvinyl alcohol.

Sericin protein (SP) is widely used as a nutrient biomaterial for biomedical and cosmeceutical applications although it shows low stability to heat and light. To overcome these problems and add value to wastewater from the silk industry, sericin protein was recovered as sericin-loaded copolymer-liposomes (SP-PVA-LP), prepared through thin film hydration. The size and morphology of the liposomes were investigated using dynamic light scattering (DLS), and electron microscopy (SEM and TEM). The particle size, liposome surface morphology and encapsulation efficiency of SP were dependent on PVA concentration. The hydrodynamic size of the nanoparticles was between 200 and 400nm, with the degree of negative charge contingent on sericin loading. SEM and TEM images confirmed the mono-dispersity, and spherical nature of the particles, with FTIR measurements confirming the presence of surface bound PVA. Exposure of liposomes to 500ppm sericin highlighted a dependence of encapsulation efficiency on PVA content; 2% surface PVA proved the optimal level for sericin loading. Cytotoxicity and viability assays revealed that SP-loaded surface modified liposomes promote cellular attachment and proliferation of human skin fibroblasts without adverse toxic effects. Surface modified copolymer liposomes show high performance in maintaining structural stability, and promoting enhancements in the solubility and bio-viability of sericin. Taken together, these biocompatible constructs allow for effective controlled release, augmenting sericin activity and resulting in effective drug delivery systems.

Efficacy of cinnamon bark oil and cinnamaldehyde on anti-multidrug resistant Pseudomonas aeruginosa and the synergistic effects in combination with other antimicrobial agents.

BACKGROUND: The emergence of drug resistant pathogens becomes a crucial problem for infectious diseases worldwide. Among these bacteria, Pseudomonas aeruginosa is one of which highly resists to many currently used drugs and becomes a major concern in public health. Up till now, the search for potential antimicrobial agents has been still a challenge for researchers. METHODS: Broth microdilution assay was used to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the essential oils and antibiotics against P. aeruginosa. Inhibition activity of the essential oils under vapor condition was examined to obtain the minimum inhibitory dose (MID). Time-kill assay included in this study was performed according to CLSI guideline. Bioautographic assay was used to detect active components of the essential oil. Synergistic effect with currently used antibiotics was further examined by checkerboard assay. RESULTS AND DISCUSSION: In this study, a variety of essential oils were examined for anti-multidrug resistant P. aeruginosa (MDR-PA) activity, of which cinnamon bark oil showed the strongest antimicrobial activity against all clinical-isolated MDR-PA strains with MIC of 0.0562-0.225 % v/v and MBC of 0.1125-1.8 % v/v. Bioautographic results demonstrated that the active compounds of cinnamon bark oil were cinnamaldehyde and eugenol which showed strong inhibitory effect against P. aeruginosa. Interestingly, cinnamaldehyde, a major constituent of cinnamon bark oil, possessed stronger antimicrobial effect to P. aeruginosa than eugenol. Under gaseous condition, cinnamon bark oil and cinnamaldehyde showed antibacterial activity against MDR-PA strains with MID of 0.5-1 mg/L. Moreover, combination of cinnamon bark oil or cinnamaldehyde with currently used antibiotics was further studied by checkerboard assay to examine synergistic interactions on clinically isolated MDR-PA strains. Cinnamon bark oil and cinnamaldehyde combined with colistin demonstrated synergistic rates at 16.7 and 10 %, respectively. CONCLUSION: These results indicated that cinnamon bark oil and cinnamaldehyde might be active natural compounds which could be further examined as alternative treatment for multidrug-resistant P. aeruginosa infection.

Surface modification of PLGA nanoparticles by carbopol to enhance mucoadhesion and cell internalization.

Mucoadhesive poly (lactic-co-glycolic acid) (PLGA) nanoparticles having a modified shell-matrix derived from polyvinyl alcohol (PVA) and Carbopol (CP), a biodegradable polymer coating, to improve the adhesion and cell transfection properties were developed. The optimum formulations utilized a CP concentration in the range of 0.05-0.2%w/v, and were formed using modified emulsion-solvent evaporation technique. The resulting CP-PLGA nanoparticles were characterized in terms of their physical and chemical properties. The absorbed CP on the PLGA shell-matrix was found to affect the particle size and surface charge, with 0.05% CP giving rise to smooth spherical particles (0.05CP-PLGA) with the smallest size (285.90 nm), and strong negative surface charge (-25.70 mV). The introduction of CP results in an enhancement of the mucoadhesion between CP-PLGA nanoparticles and mucin particles. In vitro cell internalization studies highlighted the potential of 0.05CP-PLGA nanoparticles for transfection into SiHa cells, with uptake being time dependent. Additionally, cytotoxicity studies of CP-PLGA nanoparticles against SiHa cancer cells indicated that low concentrations of the nanoparticles were non-toxic to cells (cell viability >80%). From the various formulations studied, 0.05CP-PLGA nanoparticles proved to be the optimum model carrier having the required mucoadhesive profile and could be an alternative therapeutic efficacy carrier for targeted mucosal drug delivery systems with biodegradable polymer.

Efficacy of capsicum oleoresin nanocapsules formulation by the modified emulsion-diffusion method.

In this study, we investigated the effect of high pressure homogenizer on the physico-chemical properties of capsicum oleoresin loaded nanoemulsion (NE) or nanocapsules (NCs) based on the emulsion-diffusion method. According to the application stage of high pressure process at principle emulsion-diffusion method, NCs was prepared by conventional-emulsion-diffusion method (CED), modified-emulsion-microfluidization-diffusion method (MEMD) and modified-emulsion-diffusion-microfluidization method (MEDM). The nanocapsules of MEMD showed homogeneous and the smallest particle size as compared with CED. In addition, MEMD presented the surface tension at the value 36.5 mN/m. The encapsulated capsicum oleoresin was generated the bright color and suppressed the dark red color. Furthermore, MEMD gave the high encapsulation efficiency of capsicum oleoresin around 95% and showed the slow release rate. On the other hand, MEDM presented the non-homogeneous and agglomerate of the particle, low percentage of encapsulation efficiency and the high initial release rate when compared with CED and MEMD methods. According these results, it was supposed that the microfluidization was interesting technique to ameliorate the physical properties and efficiency of NCs. However, it was depending on the appropriate combination of microfluidization based on the emulsion-diffusion method.

Antibacterial effect of apatite-coated titanium dioxide for textiles applications.

An antibacterial activity of apatite-coated titanium dioxide (TiO2) against four types of bacteria (Staphylococcus aureus, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and Micrococcus luteus) was investigated. Its antibacterial performance was observed under black light, visible light, and dark conditions. The number of viable bacteria decreased with irradiation time and became most prominent at 24 hours. Distortion of bacterial cells by the nanoparticles was demonstrated by scanning electron microscopy. Apatite-coated TiO2 was fixed on cotton textiles by dip-coat technique, and the antimicrobial properties of corresponding fabrics were then investigated. The effect of irradiation source on antimicrobial activity of coated cotton fabrics was examined, wherein black-light irradiation demonstrated higher antibacterial activity than either visible-light irradiation or dark conditions. Microbial populations of coated cotton fabrics decreased with increasing irradiation intensity. Coated cotton fabrics have been shown to be nontoxic to human dermal fibroblasts. Our findings suggest that the presence of apatite-coated TiO2 shows antibacterial activity in the presence of black light or visible light, suggesting its potential use in reducing the risk of microorganism transmission for textile applications.

Antibacterial activity of Thai medicinal plants against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen which causes severe morbidity and mortality worldwide. Seventeen Thai medicinal plants were investigated for their activity against MRSA. Garcinia mangostana was identified as the most potent plant, and its activity was traced to the prenylated xanthone, alpha-mangostin (MIC and MBC values of 1.95 and 3.91 microg/ml, respectively).

Effect of Garcinia mangostana on inflammation caused by Propionibacterium acnes.

The present study was aimed to investigate the activity of Thai medicinal plants on inflammation caused by Propionibacterium acnes in terms of free radical scavenging and cytokine reducing properties. P. acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. Antioxidant activity was determined by DPPH scavenging and NBT reduction assay. The result showed that Garcinia mangostana possessed the most significant antioxidant activity and reduced reactive oxygen species production. Houttuynia cordata, Eupatorium odoratum, and Senna alata had a moderate antioxidant effect. In addition, Garcinia mangostana extracts could reduce the TNF-alpha production as determined by ELISA. Garcinia mangostana was highly effective in scavenging free radicals and was able to suppress the production of pro-inflammatory cytokines. This study has identified the promising source of anti-inflammatory agent which could be useful in treatment of acne vulgaris.

Antimicrobial effects of Thai medicinal plants against acne-inducing bacteria.

Propionibacterium acnes and Staphylococcus epidermidis have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Thai medicinal plants against these etiologic agents of acne vulgaris. Crude extracts were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion method showed that 13 medicinal plants could inhibit the growth of Propionibacterium acnes. Among those, Senna alata, Eupatorium odoratum, Garcinia mangostana, and Barleria lupulina had strong inhibitory effects. Based on a broth dilution method, the Garcinia mangostana extract had the greatest antimicrobial effect. The MIC values were the same (0.039 mg/ml) for both bacterial species and the MBC values were 0.039 and 0.156 mg/ml against Propionibacterium acnes and Staphylococcus epidermidis, respectively. In bioautography assay, the Garcinia mangostana extract produced strong inhibition zones against Propionibacterium acnes. Antimicrobial activity from fractions of column chromatography revealed one of the active compounds in Garcinia mangostana could be mangostin, a xanthone derivative. Taken together, our data indicated that Garcinia mangostana had a strong inhibitory effect on Propionibacterium acnes and Staphylococcus epidermidis. Therefore, this plant would be an interesting topic for further study and possibly for an alternative treatment for acne.