Preparation of nanoemulsion spray from Moslae Herba volatile oil and its antibacterial activity / 中国中药杂志

Moslae Herba is a commonly used aromatic Chinese medicinal with volatile oil as the main effective component and exhibits broad-spectrum antibacterial and antiviral effects. However, the irritation and instability of Moslae Herba volatile oil necessitate the preparation into a specific dosage form. In this study, the steam distillation method was employed to extract the Moslae Herba volatile oil. The content of thymol and carvacrol in Moslae Herba volatile oil was determined by HPLC as(0.111 9±0.001 0) and(0.235 4±0.004 7) mg·mL~(-1), respectively. Pseudo-ternary phase diagrams and surfactants compounding were applied in the selection of the optimal excipients(surfactant and cosurfactant). On this basis, a nanoemulsion was prepared from the Moslae Herba volatile oil and then loaded into pressure vessels to get sprays, whose stability and antibacterial activity were evaluated afterward. With clarity, viscosity, smell and body feeling as comprehensive indexes, the optimal formulation of the Moslae Herba volatile oil nanoemulsion was determined as follows: Moslae Herba volatile oil∶peppermint oil∶cremophor EL∶absolute ethanol∶distilled water 7.78∶1.58∶19.26∶6.15∶65.23. The as-prepared nanoemulsion was a light yellow transparent liquid, with Tyndall effect shown under the irradiation of parallel light. It has the pH of 5.50, conductivity of 125.9 μS·cm~(-1), average particle size of 15.45 nm, polydispersity index(PDI) of 0.156, and Zeta potential of-17.9 mV. Under a transmission electron microscope, the Moslae Herba volatile oil nanoemulsion was presented as regular spheres without adhesion and agglomeration. Stability test revealed that the Moslae Herba volatile oil nanoemulsion was stable at 4-55 ℃, which was free from demulsification and stratification within 30 days. After the centrifugation at 12 000 r·min~(-1) for 30 min, there was no stratification either. The nanoemulsion had good inhibitory effects on Escherichia coli, Staphylococcus aureus and resistant S. aureus strains, with the minimum inhibitory concentrations of 0.39, 3.12 and 1.56 mg·mL~(-1), respectively. The above results demonstrated that the nanoemulsion was prepared feasibly and showed stable physical and chemical properties and good antibacterial effects. This study provides a practicable technical solution for the development of anti-epidemic and anti-infection products from Moslae Herba volatile oil.

Analysis of Chemical Constituents of Volatile Oils in Menthae Haplocalycix Herba-Schizonepetae Herba and Herbal Pairs and Comparison of Anti-bacterial Effects in Vitro / 中国实验方剂学杂志

Objective: To discuss the effect of herbal compatibility on the components of volatile oils in Menthae Haplocalycix Herba and Schizonepetae Herba,and the comparison of the anti-bacterial effects in vitro,in order to provide the experimental basis for investigating the effective material basis of their herb-pair. Method: Steam distillation was used to extract volatile oils of Menthae Haplocalycix Herba, Schizonepetae Herba,and their combination. GC-MS was employed to analyze their volatile oils,and the anti-bacterial effects in vitro were compared. Result: Totally 50 compounds were identified from the volatile oils of Menthae Haplocalycix Herba;41 compounds were identified from the volatile oils of Schizonepetae Herba;and 60 compounds were identified from the volatile oils of their herbal pairs. A total of 27 common compounds were found in the samples of three volatile oils. Totally 5 new compounds were detected in the volatile oils of their herbal pairs,and 9 compounds were not detected. In vitro,volatile oils of both their herbal pairs and individual herbs had bacteriostatic effects on dung Enterococcus (ATCC2922),Staphylococcus aureus (ATCC2923),Escherichia coli (ATCC35218),and E. coli (ATCC25922). Among them,volatile oils of their herbal pairs had stronger bacteriostatic effects on dung enterococcus (ATCC2922) and staphylococcus aureus (ATCC2923) than volatile oils of individual herbs. Moreover,the order of the inhibitory effects of volatile oils on E. coli (ATCC35218 and ATCC25922) were "herbal pairs=peppermint > herba schizonepetae". Conclusion: There were some changes between the volatile oils of individual herbs and the volatile oils of their herbal pairs. These phenomena may be caused by the occurrence of certain chemical reactions and physical changes in compatibility of decocting process. The antibacterial effects of volatile oils of their herbal pairs were better than those of individual herbs in vitro.

Anti-bacterial effects of lavender and peppermint oils on Streptococcus mutans / 대한구강보건학회지

OBJECTIVES: The main objectives of this study were to verify the antibacterial activity of two essential oils, lavender and peppermint, against dental caries and to review their synergistic effect when used in combination. Our results provide basic data for the evaluation of the use of these two substances towards the prevention and cure of dental caries. METHODS: The sample solutions of lavender and peppermint oils were prepared in three different concentrations (30%, 50%, and 70% (v/v)) by diluting them with third-distilled water and Tween 20. Streptococcus mutans was selected as the bacterial species for testing. The disk diffusion method was used to measure the antibacterial activity of the sample solutions. For generating growth curves and measuring the number of clusters of the bacterial, the liquid medium-dilution method was used; the absorbance of the medium was measured at 600 nm after 3, 6, 12 and 24 hours. RESULTS: When the antibacterial activity of the oils was tested via the disk diffusion method, the activity improved with increasing concentrations of all the sample solutions of peppermint, lavender, and the blend, but there was no significant difference between them with respect to the type of oil. In the growth curves of S. mutans, growth inhibition was observed after 12 hours. The inhibitory effect of 30% lavender oil on growth was 64.9% and 80.1% after 12 and 24 hours of treatment, respectively whereas that of peppermint oil was 71.3% and 80.1% after 12 and 24 hours of treatment, respectively. The inhibitory effect of the blended oil was 71.9% and 81.0% after 12 and 24 hours of treatment, respectively. CONCLUSIONS: Further research is still required in order to determine the efficacy of lavender and peppermint oils, as well as other essential oils, for wider use in preventing dental caries.

Anti-bacterial Effects of Baicalin on One Escherichia coli Strain Carrying NDM-1 Gene / 现代检验医学杂志

Objective To examine the bacteriostasis of baicalin against Escherichiacoli strain carrying NDM-1 gene.Methods Minimal inhibitory concentration(MIC)and minimal bactericidal concentration(MBC)were determined by broth dilution method.Synergy function was designed withcheckerboard method.Anti-infection effect in vivo of baicalin was observed in mice with bacteremia.Results In vitro antibacterial tests showed that the MIC and MBC baicalin were 8 mg/ml.Synergistic inhibitory effect was observed between baicalin and imipenem (FIC=0.125).In vivo inhibition experiments showed that ba-icalin had decreased the mortality of 25% of Escherichiacoli Strain carrying NDM-1 gene infection in mice.Conclusion Ba-icalin has antibacterial effect on NDM-1 E.coli.