Six Spain Thymus essential oils composition analysis and their in vitro and in silico study against Streptococcus mutans.

BACKGROUND: Streptococcus mutans is a well-known oral pathogen that plays a critical role in the development of dental caries. Many studies have been directed to discover the chemical compounds present in natural products to inhibit the growth and biofilm formation activity of S. mutans. Thymus essential oils exhibit good inhibition on the growth and pathogenesis of S. mutans. However, details about the active compounds in Thymus essential oil and the inhibition mechanism still remain unclear. The aim of this study was to investigate the antimicrobial activity of 6 Thymus species (Three samples of Thymus vulgaris, two samples of Thymus zygis, and one sample of Thymus satureioides essential oils) on S. mutans, to identify the potential active components, and to reveal the underlying mechanism. METHODS: The composition of Thymus essential oils was analyzed by gas chromatography-mass spectrometry. And its antibacterial effect was evaluated based on the bacterial growth, acid production, biofilm formation and genetic expression of virulence factors by S. mutans. Potential active components of the Thymus essential oil were identified using molecular docking and correlation analysis. RESULTS: GC-MS analysis showed that the major components in the 6 Spain Thymus essential oils were linalool, α-terpineol, p-cymene, thymol and carvacrol. MIC and MBC analysis showed that 3 Thymus essential oils showed very sensitive antimicrobial activity, and were chosen for further analysis. The 3 Thymus essential oil exhibited a significant inhibitory effect on acid production, adherence and biofilm formation of S. mutans and the expression of virulence genes, such as brpA, gbpB, gtfB, gtfC, gtfD, vicR, spaP and relA. Correlation analysis showed that phenolic components, such as carvacrol and thymol, were positively related to DIZ value, which suggests that they are the potential antimicrobial components. Molecular docking between the Thymus essential oil components and virulence proteins also found that carvacrol and thymol exhibited strong binding affinity with functional domains of virulence genes. CONCLUSIONS: Thymus essential oil showed significant inhibition against the growth and pathogenesis of S. mutans depending on their composition and concentration. And phenolic compounds, such as carvacrol and thymol, are the major active components. Thymus essential oil could be used in oral healthcare products as a potential anti-caries ingredient.

[New thoughts on material basis and mechanism of Yin-tonifying traditional Chinese medicine in treatment of diabetes mellitus and its complications].

Diabetes mellitus is a serious chronic metabolic disease, and the patient's hyperglycemia is often accompanied by complications. In the circles of medical science, traditional Chinese medicine(TCM) has the earliest knowledge and research about diabetes. According to TCM, the clinical characteristics of diabetes mellitus were basically the same as "Xiaoke". TCM also believes that "Yin deficiency and dryness heat" was the main pathogenesis of diabetes. Therefore, Yin-tonifying TCMs is widely used in clinical treatment of diabetes mellitus, including Dendrobii Caulis, Lilii Bulbus, Ophiopogonis Radix, Polygonati Rhizome. The effective component for treating diabetes in the above Chinese materia medica is polysaccharides, which is used to treat complications of diabetes mellitus, like vascular disease, nephropathy, retinopathy, peripheral neuropathy. According to literature reports, except for specific some Yin-tonifying TCMs with effective ingredients for preventing and treating diabetes, other Yin-tonifying TCMs only contain water, alcohol extracts or polysaccharides in the treatment of diabetes. However, due to unclear material basis, dose-effect relationship and mechanism target of hypoglycemic drugs, Yin-tonifying TCMs are restricted in clinical application, with certain difficulties in in-depth studies. In this paper, the literatures related to the treatment of diabetes mellitus and its complications with Yin-tonifying TCM are analyzed and summarized, the existing problems are analyzed, and the research ideas and methods based on chromatographic technology and metabonomics are put forward, in order to provide reference for the application and development of Yin-tonifying TCM.

[Characterization of sediment of water extract of Guizhi decoction and its effect on relevant compound (fractions) in decoction].

In order to study the effect of sediment of water extract of Guizhi decoction on the stability, clarity and peaks area, and characterize the chemical composition of the sediments, HPLC and MS methods were established. Through comparison of the common peak areas and the turbidity value of water extract and filtrate, the sediments could greatly change the common peak areas of the decoction (for more than 5 times of the study standard); at the same time, the turbidity value of the decoction could increase by （38.66±1.57）% in 48 h [particularly by （24.54±1.68）% in 6 h]. The test indicated that the sediments had an effect on the stability and clarity under the test conditions in Guizhi decoction. The study confirmed that the sediments were mainly derived from Cassia twig, Paeonia lactiflora and Glycyrrhiza uralensis. On the basis of the reference information, the accurate molecular weight and fragment ion information provided by LC-MS were analyzed, the molecular formula of sediments components A-F were determined, and the possible structural information of components B, C, D and F were deduced. It was suggested that the multi-index, multi-target and multi-angle analysis could ensure the quality of traditional Chinese medicine and the effect of clinical medication. The study also suggested the effect of the sediments on clinical application and the preparation of traditional Chinese medicine.

[Research progress on chemical constituents, pharmacological mechanism and clinical application of Guizhi decoction].

Guizhi Decoction was one of the most commonly used traditional Chinese Medicine which possesses the effects of "jie-ji-fa-biao, regulating Ying and Wei". It was mainly used to treat mind-cold due to exogenous evils such as fever, headache, sweating, hate the wind, et al. Modern studies indicated that the chemical constituents of Guizhi decoction mainly include phenylpropanoid, monoterpenes, organic acids, flavonoids, triterpenoid saponins and so on. Pharmacological experimental studies had shown that Guizhi decoction could play a big role in dual-directional regulation on sweat gland, body temperature, immune function, gastrointestinal peristalsis, and blood pressure, and could also play the role of anti-inflammatory, antibacterial, antiviral, anti-allergic, analgesic, hypoglycemic, and cardiovascular protection. Many diseases such as internal, external, gynecological and pediatric diseases were treated in the clinical by using Guizhi decoction and its analogous formulae involving circulatory, immune, urinary, reproductive, endocrine, digestive, nervous and other systems. This article reviews the latest research progress of Guizhi decoction from three aspects: chemical constituents, pharmacological mechanism and clinical application. It will provide reference for further research and development of Guizhi decoction.

Cytotoxic steroidal saponins from Polygonatum zanlanscianense.

Four new steroidal saponins, polygonatosides A-D (1-4), were isolated from the rhizomes of Polygonatum zanlanscianense, together with six known spirostanols (5-10) and a known megastigmane glycoside (11). Their structures were elucidated on the basis of spectroscopic analysis and the results of acidic and enzymatic hydrolysis. The cytotoxic activities of 1-11 against HeLa cells are described.

Four new steroid constituents from the waste residue of fibre separation from Agave americana leaves.

Three new steroidal saponins, named agamenosides H-J (1-3), and a new cholestane steroid agavegenin D (4) were isolated from the waste residue of fibre separation from Agave americana leaves, together with six known steroids. Structures of the new compounds 1-4 were deduced to be (22S,23S,24R,25S)-24-[(beta-D-glucopyranosyl)oxy]-5alpha-spirostane-3beta,6alpha,23-triol 6-O-beta-D-glucopyranoside (1), (22S,23S,24R,25S)-5alpha-spirostane-3beta,23,24-triol 24-O-beta-D-glucopyranoside (2), (22S,23S,25R,26S)-23,26-epoxy-5alpha-furostane-3beta,22,26-triol 26-O-beta-D-glucopyranoside (3), and (22S,25S)-5alpha-cholestane-3beta,16beta,22,26-tetrol (4), respectively, by means of spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of hydrolytic cleavage.

Spirostanol and furostanol glycosides from the fresh tubers of Polianthes tuberosa.

Six new steroid glycosides--two spirostanols, polianthosides B and C (1, 2), and four furostanols, polianthosides D-G (3-6)--were isolated from the fresh tubers of Polianthes tuberosa, together with seven known spirostanols (7-13) and a known furostanol (14) saponins. Their structures were elucidated on the basis of spectroscopic analysis and the results of acidic and enzymatic hydrolysis. The cytotoxic activities of 1-14 against HeLa cells are reported.

Model-order reduction of nonlinear models of electromagnetic phased-array hyperthermia.

A method based on the Karhunen-Loéve (KL) transform is proposed for the reduction of large-scale, nonlinear ordinary differential equations such as those arising from the finite difference modeling of biological heat transfer. The method of snapshots is used to expedite computation of the required quantities in the KL procedure. Guidelines are presented and validated for snapshot selection and resultant basis series truncation, emphasizing the special physical features of the electromagnetic phased-array heat transfer physics. Applications to fast temperature prediction are presented.

Optimization of electromagnetic phased-arrays for hyperthermia via magnetic resonance temperature estimation.

A technique for the optimization of electromagnetic annular phased arrays (APAs) for therapeutic hyperthermia has been developed and implemented. The controllable inputs are the amplitudes and phases of the driving signals of each element of the array. Magnetic resonance imaging (MRI) is used to estimate noninvasively the temperature distribution based on the temperature dependence of the proton resonance frequency (PRF). A parametric model of the dynamics that couple the control inputs to the resultant temperature elevations is developed based on physical considerations. The unknown parameters of this model are estimated during a pretreatment identification phase and can be continuously updated as new measurement data become available. Based on the parametric model, a controller automatically chooses optimal phases and amplitudes of the driving signals of the APA. An advantage of this approach to optimizing the APA is that no a priori information is required, eliminating the need for patient-specific computational modeling and optimization. Additionally, this approach represents a first step toward employing temperature feedback to make the optimization of the APA robust with respect to modeling errors and physiological changes. The ability of the controller to choose therapeutically beneficial driving amplitudes and phases is demonstrated via simulation. Experimental results are presented which demonstrate the ability of the controller to choose optimal phases for the APA using only information from magnetic resonance thermometry (MRT).

[A new steroidal glycoside from fermented leaves of Agave americana].

OBJECTIVE: To investigate the constituents of fermented leaves of Agave americana, and discover new compounds. METHOD: Compounds were purified with silica gel and C8 reverse--phase silica gel column chromatography. The structures were elucidated by chemical and spectroscopic evidence. RESULT: Three steroidal compounds were obtained and their structures were identified as (25R)-5 alpha-spirostan-3 beta, 6 alpha, 23 alpha-triol 6-O-beta-D-glucopyranoside(1), (25R)-5 alpha-spirostan-3 beta, 6 alpha, 23 alpha-triol-3, 6-di-O-beta-D-glucopyranoside (cantalasaponin-1) (2) and (25R)-5 alpha-spirostan-3 beta, 6 alpha, 23 alpha-triol(hongguanggenin) (3). CONCLUSION: Compound 1 is new compound, named agamenoside C.