Project description:BackgroundThe biological activity and pharmacological effects of rare ginsenosides have been proven to be superior to those of the major ginsenosides, but they are rarely found in ginseng.MethodsGinsenoside Rb1 was chemically transformed with the involvement of methanol molecules by a synthesized heterogeneous catalyst 12-HPW@MeSi, which was obtained by the immobilization of 12-phosphotungstic acid on a mesoporous silica framework. High-performance liquid chromatography coupled with mass spectrometry was used to identify the transformation products.ResultsA total of 18 transformation products were obtained and identified. Methanol was found to be involved in the formation of 8 products formed by the addition of methanol molecules to the C-24 (25), C-20 (21) or C-20 (22) double bonds of the aglycone. The transformation pathways of ginsenoside Rb1 involved deglycosylation, addition, elimination, cycloaddition, and epimerization reactions. These pathways could be elucidated in terms of the stability of the generated carbenium ion. In addition, 12-HPW@MeSi was able to maintain a 60.5% conversion rate of Rb1 after 5 cycles.ConclusionTandem and high-resolution mass spectrometry analysis allowed rapid and accurate identification of the transformation products through the characteristic fragment ions and neutral loss. Rare ginsenosides with methoxyl groups grafted at the C-25 and C-20 positions were obtained for the first time by chemical transformation using the composite catalyst 12-HPW@MeSi, which also enabled cyclic heterogeneous transformation and facile centrifugal separation of ginsenosides. This work provides an efficient and recyclable strategy for the preparation of rare ginsenosides with the involvement of organic molecules.
Project description:Ginsenoside (ginseng saponin), the principal component of ginseng, is responsible for the pharmacological and biological activities of ginseng. We isolated lactic acid bacteria from Kimchi using esculin agar, to produce β-glucosidase. We focused on the bio-transformation of ginsenoside. Phylogenetic analysis was performed by comparing the 16S rRNA sequences. We identified the strain as Lactobacillus (strain 6105). In order to determine the optimal conditions for enzyme activity, the crude enzyme was incubated with 1 mM ginsenoside Rb1 to catalyse the reaction. A carbon substrate, such as cellobiose, lactose, and sucrose, resulted in the highest yields of β-glucosidase activity. Biotransformations of ginsenoside Rb1 were analyzed using TLC and HPLC. Our results confirmed that the microbial enzyme of strain 6105 significantly transformed ginsenoside as follows: Rb1→gypenoside XVII, Rd→F2 into compound K. Our results indicate that this is the best possible way to obtain specific ginsenosides using microbial enzymes from 6105 culture.
Project description:Curcumin (Cur) can be used as a photosensitizer in the photodynamic therapy (PDT) of cancer, but its low bioavailability limits further clinical application. A mesoporous silica-based drug delivery system (PEGylated mesoporous silica nanoparticles, MSN-PEG@Cur) was designed to solve the problem. The successful preparation of MSN-PEG@Cur was characterized by several physico-chemistry techniques. The endocytosis, ROS generation and in vitro anti-cancer efficacy of MSN-PEG@Cur were evaluated in detail step by step. The results indicated that MSN-PEG@Cur could be effectively endocytosed into cells and release Cur, which can promptly generate ROS upon irradiation, achieving effective PDT in cancer treatment. This MSNs-based drug delivery system provides an alternative strategy for Cur loading and PDT of cancer.
Project description:Combination of chlorhexidine (CHX) and silver ions could engender synergistic bactericidal effect and improve the bactericidal efficacy. It is highly desired to develop an efficient carrier for the antiseptics codelivery targeting infection foci with acidic microenvironment. In this work, monodisperse mesoporous silica nanoparticle (MSN) nanospheres were successfully developed as an ideal carrier for CHX and nanosilver codelivery through a facile and environmentally friendly method. The CHX-loaded, silver-decorated mesoporous silica nanoparticles (Ag-MSNs@CHX) exhibited a pH-responsive release manner of CHX and silver ions simultaneously, leading to synergistically antibacterial effect against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. Moreover, the effective antibacterial concentration of Ag-MSNs@CHX showed less cytotoxicity on normal cells. Given their synergistically bactericidal ability and good biocompatibility, these nanoantiseptics might have effective and broad clinical applications for bacterial infections.
Project description:Development of room-temperature gas sensors is a much sought-after aspect that has fostered research in realizing new two-dimensional materials with high surface area for rapid response and low-ppm detection of volatile organic compounds (VOCs). Herein, a fast-response and low-ppm ethanol gas sensor operating at near room temperature has been fabricated successfully by utilizing cubic mesoporous graphitic carbon nitride (g-CN, commonly known as g-C3N4), synthesized through template inversion of mesoporous silica, KIT-6. Upon exposure to 50 ppm ethanol at 250 °C, the optimized Ag/g-CN showed a significantly higher response (R a/R g = 49.2), fast response (11.5 s), and full recovery within 7 s in air. Results of sensing tests conducted at 40 °C show that the sensor exhibits not only a highly selective response to 50 ppm (R a/R g = 1.3) and 100 ppm (R a/R g = 3.2) of ethanol gas but also highly reversible and rapid response and recovery along with long-term stability. This outstanding response is due to its easily accessible three-dimensional mesoporous structure with higher surface area and unique planar morphology of Ag/g-CN. This study could provide new avenues for the design of next-generation room-temperature VOC sensors for effective and efficient monitoring of alarming concern over indoor environment.
Project description:Photothermal therapy possesses great advantages for the treatment of drug-resistant tumors. Herein, Near Infrared (NIR)-triggered photothermal nanoparticles were developed through loading indocyanine green (ICG), a kind of NIR dye, into amino group-modified silica nanoparticles (SiO2-NH2 NPs). SiO2-NH2 NPs were prepared with immobilization of the amino groups into the framework of silica nanoparticles (SiO2 NPs) by employing (3-aminopropyl)-triethoxysilane (APTES). Before and after the modification of the amino group, the particle sizes of SiO2 NPs showed similar value, around 100 nm. ICG was further adsorbed into SiO2-NH2 NPs by electrostatic attraction to enable SiO2-NH2@ICG NPs as a kind of photothermal agent. The loading rate of ICG to SiO2-NH2 was greatly increased compared to unmodified SiO2, and the stability of ICG was also improved. Moreover, the SiO2-NH2@ICG NPs exhibited efficient photothermal effects due to ICG transforming laser power into local heat through the connected ICG, when NIR laser irradiation turned on for a couple of minutes. Finally, the in vitro antitumor efficacy of SiO2-NH2@ICG NPs was investigated by recording cell proliferation rate and further chronicled the apoptotic morphology evidence by a Calcein-AM/PI fluorescent staining assay, indicating the efficient photothermal targeted therapy for the HepG2 tumor cells.
Project description:Macrophages are involved mainly in the balance between inflammation and tenogenesis during the healing process of tendinopathy. However, etiological therapeutic strategies to efficiently treat tendinopathy by modulating macrophage state are still lacking. In this study, we find that a small molecule compound Parishin-A (PA) isolated from Gastrodia elata could promote anti-inflammatory M2 macrophage polarization by inhibiting gene transcription and protein phosphorylation of signal transducers and activators of transcription 1. Local injection or sustained delivery of PA by mesoporous silica nanoparticles (MSNs) could almost recover the native tendon's dense parallel-aligned collagen matrix in collagenase-induced tendinopathy by modulating macrophage-mediated immune microenvironment and preventing heterotopic ossification. Especially, MSNs decrease doses of PA, frequency of injection and yield preferable therapeutic effects. Mechanistically, intervention with PA could indirectly inhibit activation of mammalian target of rapamycin to repress chondrogenic and osteogenic differentiation of tendon stem/progenitor cells by influencing macrophage inflammatory cytokine secretion. Together, pharmacological intervention with a natural small-molecule compound to modulate macrophage status appears to be a promising strategy for tendinopathy treatment.
Project description:Curcumin, a natural polyphenol extracted from a perennial herb Curcuma longa has been verified for many physiological activities such as anti-oxidant, anti-inflammatory, and anti-tumor properties. The direct use of curcumin cytotoxicity studies are limited due to its unstable chemical structure, low bioavailability, easy oxidation, and degradation by ultraviolet (UV) light etc. Trying to overcome this problem, silica-encapsulated curcumin nanoparticles (SCNP) and chitosan with silica co-encapsulated curcumin nanoparticles (CSCNP) were prepared by silicification and biosilicification methods, respectively, and encapsulated curcumin within it. We investigated the antitumor properties of SCNP and CSCNP on different tumor cell lines. Scanning electron microscopy (SEM) analysis revealed that both SCNP and CSCNP were almost spherical in shape and the average particle size of CSCNP was 75.0 ± 14.62 nm, and SCNP was 61.7 ± 23.04 nm. The results show that CSCNP has more anti-oxidant activity as compared to curcumin and SCNP. The higher cytotoxicity towards different cancerous cell lines was also observed in CSCNP treated tumor cells. It was noted that the SCNP and CSCNP has a high percentage of IC50 values in Hep G2 cells. The encapsulation of curcumin improved instability, antioxidant activity, and antitumor activity. Our results demonstrated that nanoencapsulation of curcumin with silica and chitosan not only increase curcumin stability but also enhance its cytotoxic activity on hepatocellular carcinoma cells. On the basis of these primary studies, the curcumin-loaded nanoparticles appear to be promising as an innovative therapeutic material for the treatment of tumors.
Project description:Photothermal therapy possesses great advantages for the treatment of drug-resistant tumors. Herein, Near Infrared (NIR)-triggered photothermal nanoparticles were developed through loading indocyanine green (ICG), a kind of NIR dye, into amino group-modified silica nanoparticles (SiO2-NH2 NPs). SiO2-NH2 NPs were prepared with immobilization of the amino groups into the framework of silica nanoparticles (SiO2 NPs) by employing (3-aminopropyl)-triethoxysilane (APTES). Before and after the modification of the amino group, the particle sizes of SiO2 NPs showed similar value, around 100 nm. ICG was further adsorbed into SiO2-NH2 NPs by electrostatic attraction to enable SiO2-NH2@ICG NPs as a kind of photothermal agent. The loading rate of ICG to SiO2-NH2 was greatly increased compared to unmodified SiO2, and the stability of ICG was also improved. Moreover, the SiO2-NH2@ICG NPs exhibited efficient photothermal effects due to ICG transforming laser power into local heat through the connected ICG, when NIR laser irradiation turned on for a couple of minutes. Finally, the in vitro antitumor efficacy of SiO2-NH2@ICG NPs was investigated by recording cell proliferation rate and further chronicled the apoptotic morphology evidence by a Calcein-AM/PI fluorescent staining assay, indicating the efficient photothermal targeted therapy for the HepG2 tumor cells.
Project description:This study investigated the potential use of mesoporous silica nanoparticles (MSNs) as a carrier for duloxetine hydrochloride (DX), which is prone to acid degradation. Sol-gel and solvothermal methods were used to synthesize the MSNs, which, after calcination and drug loading, were then characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) technique, thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and diffuse reflectance ultraviolet-visible (DRS-UV-Vis) spectroscopy. Releases of DX from the MSNs were good in pH 7.4 (90%) phosphate buffer but poor in acidic pH (40%). In a comparative release study between the MSNs in phosphate buffer, TW60-3DX showed sustained release for 140 h, which was higher than the other nanoparticles. The mechanism of DX release from the MSNs was studied using Peppas kinetics model. The "n" value of all three MSNs ranged from 0.45 to 1 with a correlation coefficient (r (2)) >0.9, which indicated that the release of the drug from the system follows the anomalous transport or non-Fickian diffusion. The results supported the efficacy of mesoporous silica nanoparticles synthesized here as a promising carrier for duloxetine hydrochloride with higher drug loading and greater pH-sensitive release.