Diterpene synthases from plants are key enzymes in diterpene biosynthesis, which catalyzed the initial cyclization cascade of (E, E, E,)-geranylgeranyl pyrophosphate, and generated diverse carbon skeletons. Recent research show that the structural and stereo chemical differences lead to diverse natural diterpene compounds of plants. The structures of diterpene synthases play a crucial role in cyclization function. This article mainly reviews the mechanisms, functional characteristics, and structural information of diterpene synthases according to the crystal structures and functions.

As a post-translational modification, protein acetylation plays an important role in the regulation of apoptosis, mitochondriopoiesis, lipid metabolism and cellular stress response. The imbalance of acetylation and deacetylation has been blamed for the tumorigenesis and malignant progression, which is gradually considered as a promising therapeutic target. Mammalian sirtuins, a NAD⁺ dependent class Ⅲ HDACs, are closely related to the development of aging, tumor, diabetes, obesity and neurodegenerative diseases. To provide a theoretical basis for the development of new anti-tumor drugs and the treatment of malignant tumors, this paper is prepared to focus on the irreplaceable role of sirtuins in tumor evolution:maintaining genomic stability, regulating energy metabolism, and facilitating tumor cells stemness. The modulator and pathways of sirtuins family and the research progress of agonists and inhibitors are also reviewed. The functions of SIRT2 in resistance, proliferation and metastasis have been highlighted.

Tripterygium wilfordii 3-hydroxy-3-methylglutaryl coenzyme-A reductase (TwHMGR) is an important regulation site in terpenoids metabolic pathway in cytoplasm which is the first speed limit enzyme of MVA pathway. In order to investigate the effects of TwHMGR on the biosynthesis of triptolide and celastrol in Tripterygium wilfordii, the overexpression of TwHMGR (OE-HMGR) was studied in this paper. We cloned the full-length of TwHMGR to construct overexpression vector by Gateway technology then delivered the expression vector into Tripterygium wilfordii suspension cells by gene gun. qRT-PCR was used to detect the expression of TwHMGR:the expression of TwHMGR was increased to 1.75 folds over the control group (empty vector:pH7WG2D) in the overexpression group. The accumulation of triptolide and celastrol in the suspension cells of Tripterygium wilfordii was detected by UPLC, revealing that:the contents of triptolide and celastrol were increased to 163.93% and 190.04% of over the control group in the overexpression group. Based on these findings, the positive effect on the accumulation of active terpenoids, triptolide and celastrol in Tripterygium wilfordii was found and the results laid a foundation of the synthetic biology research on important active terpenoids in Tripterygium wilfordii.

Microneedles is an efficient, safe and novel transdermal drug delivery technology that has attracted much attention in recent decades. Microneedles could break through the skin's stratum corneum barrier and have an especially significant effect on the transdermal delivery of water-soluble small molecules and biological macromolecules. In this paper, a rapid onset local anesthetic preparation of lidocaine hydrochloride was prepared based on dissolving microneedles, and related quality evaluations were carried out. The key quality indicators of prepared lidocaine hydrochloride dissolving microneedles such as drug loading amount, appearance morphology, mechanical properties, skin penetration performance, in vitro dissolution performance and local anesthetic efficacy were investigated with HPLC, SEM, texture analyzer, organic staining, histological section, in vitro dissolution test and pharmacodynamics experiments respectively. The drug loading of the dissolving microneedles array reached 68.19 ±1.55 mg, and the needle tip contained 3.57 ±0.21 mg. The microneedles has good needle shape and sufficient mechanical strength to penetrate into the skin, which is a prerequisite for the successful administration of the preparation. The in vitro dissolution time was 28.28 ±1.12 s. When applied to guinea pig back acupuncture model which was modified by guinea pig intradermal papules model, although the efficacy maintenance time was shorter than that of compound lidocaine cream, dissolving microneedles can be activated within 1 min, which was much faster than compound lidocaine cream. It is possible to increase the duration of drug efficacy by increasing the density of microneedles and preparing microneedles for sustained and controlled release in future studies. Lidocaine hydrochloride dissolving microneedles and its evaluation methods for local anesthesia were established systematically here for the first time. The rapid effect of anesthesia with lidocaine hydrochloride dissolving microneedles on the skin was worthy of further investigation.

The rheological properties of six compound gels that consists of kappa carrageenan (KC) and another excipient such as konjac gum were explored through comparison of their viscosity measured by the rotation method. The gel fluid type was dependent on the rheological curve fitted by the power-law equation. The effect of concentration on the viscosity of different compound gels was investigated by establishing the linear equation between their viscosity and concentration, the slope of which was used to determine the relation between viscosity and concentration of different compound gels. The viscous flow activation energy (E_η) was calculated by the Arrhenius equation, which was able to investigate the effect of temperature on their viscosity. The interaction between monomer and compound gels was also studied by measuring their viscosity. The results showed that six compound gels were pseudoplastic fluid. Among all compound gels, the KC-xanthan gum (KC-XG) solution exhibited the most obvious shear thinning, the strongest pseudoplasticity, while the smallest E_η, resulting in the best thermal stability of viscosity. Furthermore, the concentration of KC-sodium hyaluronate (KC-HA-Na) solution affected its viscosity significantly. The viscosity of six compound gels was greater than the summation of the two kinds of monomer gels, which suggests that there is a synergistic-viscosity interaction between KC and another excipient.

The study was designed to establish an LC-MS/MS method for the simultaneous determination of scutellarin and its major metabolite isoscutellarin in rat tissues and plasma, and to investigate the effect of different route of administration on the tissue distribution of scutellarin and its metabolite in rats. Rats were treated both intravenously and intragastrically with 20 and 80 mg·kg^-1 scutellarin, respectively. Blood and tissues were collected at predetermined intervals. The concentrations of scutellarin and isoscutellarin were determined by a validated LC-MS/MS method. The method was linear in concentration ranges of 10.0/5.00 - 5 000/2 500 ng·mL^-1 for scutellarin/isoscutellarin in the rat plasma and 30.0/15.0 - 10 000/5 000 ng·g^-1 in tissues with acceptable accuracy and precision. Data obtained after an intravenous administration of scutellarin to rats showed that the drug was distributed predominantly into the small intestine, bladder and kidney. The exposures of the metabolite isoscutellarin in plasma and tissue were both less than 5%of the parent drug. After an intragastric administration, stomach wall and small intestine were the preferred sites for scutellarin disposition, followed by bladder, adrenal gland and lung at concentrations significantly higher than its plasma concentration. The plasma exposure of isoscutellarin was higher than that of the parent drug, but its tissue exposure was significantly lower than that of scutellarin. The method established in this study was successfully applied to characterization of the tissue profiles of scutellarin and its metabolite in rats. The route of administration has a marked impact on the disposition of scutellarin and its metabolite in rats. Ratios of the tissue to plasma concentrations after intragastric administration were obviously higher than those after intravenous administration. Scutellarin could pass the blood-brain barrier in a marked extent, but isoscutellarin was not detected in the rat brain, which may be attributed to the fact that scutellarin is a higher-affinity substrate for OATP than isoscutellarin.

The study was aimed to identify the related substances of vortioxetine hydrobromide by hyphenated techniques. The separation of the six related substances was performed on a Phenomenex Luna Phenyl- Hexyl column (150 mm×4.6 mm, 3 μm) by linear gradient elution of acetonitrile and ammonium formate solution. Electrospray and atmospheric pressure chemical ionization were interfaced respectively with high resolution Q-TOF/MS for the determination of the accurate mass and elemental composition of the parent ions of the related substances, and triple quadrupole tandem mass was employed for the product mass spectra determination. The structures of the related substances were identified through elucidation of the fragment ions. Vortioxetine hydrobromide and its related substances were adequately separated under the established HPLC conditions. Six major related substances were detected and identified for the first time. The data provides a reference for optimization of the synthetic process and quality assurance of vortioxetine hydrobromide.

As an important drug carrier, liposome has the advantages of high biocompatibility and low immunogenicity. It has been widely used in the field of drug delivery, especially the targeted treatment of tumors. However, traditional liposomes are composed of flowing dynamic phospholipid membranes, which are easy to fuse together, resulting in aggregation and drug leakage. In addition, the lower degree of polyethylene glycol (PEG) modification also limits the targeted delivery performance of the vector in vivo. In view of the problems, a nanoparticle-targeted drug delivery system combining the inorganic carrier calcium phosphate with liposomes was designed, namely lipid calcium phosphate (LCP). Using doxorubicin (DOX) as a model drug, doxorubicin-loaded lipid calcium phosphate nanoparticles (DOX/LCP) were prepared by reverse microemulsion method, and the preparation conditions were investigated. The structure and morphology of calcium phosphate cores were observed by infrared spectroscopy, EDS spectroscopy, and transmission electron microscopy. The particle size, encapsulation efficiency, drug loading, stability and release behavior in vitro of DOX/LCP were investigated. Confocal microscopy and flow cytometry were used to qualitatively and quantitatively evaluate the uptake of DOX in drug-resistant tumor cell line MCF-7/DOX by LCP, respectively, and the thiazolium MTT colorimetric method was used to examine its cytotoxicity. LCP exhibited a typical core-shell structure with good size uniformity and dispersibility. The particle size was in (48.6 ±3.9) nm, the potential was in (-12.1 ±1.2) mV, and the encapsulation efficiency was above 80%. Moreover, it has a good stability in simulated plasma. In vitro release of LCP had a significant pH dependence. When the pH of the environment was 7.4, the cumulative release within 24 hours was less than 20%; as the pH of the release medium decreases, the release rate of DOX/LCP was accelerated gradually. Accumulated release over 24 hours exceeded 90% in the pH 4.5 medium. LCP significantly promoted the uptake and accumulation of DOX by drug-resistant cells, and the inhibition rate of drug-resistant tumors was significantly increased in vitro. The half maximal inhibitory concentrations (IC₅₀) of LCP/DOX and free DOX were 4.6 and 11.8 μg·mL^-1, respectively, and there was a significant difference between the two groups (P < 0.05). In summary, the LCP prepared in this study had a small particle size, high encapsulation efficiency and good stability. It had environmental responsiveness and potential inhibition of tumor drug resistance, which suggests a potential in the clinical application.

MCT is an important key enzyme in the terpenoid biosynthesis in MEP pathway. In this study, Gateway technology was used to construct RNAi vector of TwMCT, and a vector fragment with a size of 484 bp was obtained. The TwMCT RNAi vector was transferred into the suspension cells of Tripterygium wilfordii by gene gun. Accumulation of terpenoids was assayed by UPLC, and the result showed that the content of triptolide and celastrol in cells decreased by 23.4% and 42.8%, respectively, compared with the control group pK7GWIWG2D. Moreover, the gene expression of TwMCT and major genes in terpenoid biosynthesis pathway was detected by qRT-PCR, which demonstrated that the expression of TwMCT reduced by 29.2% relative to that of the control group pK7GWIWG2D, and the relative expression of TwDXR, TwGGPS, TwHMGR and TwHMGS diminished by 36.3%, 31.3%, 62.2%, and 29.1%, respectively, but the expression of TwDXS was up-regulated by 114.2%, and there was no significant change in TwFPS. Thus, it was verified in vivo that interference with TwMCT expression significantly inhibited the accumulation of triptolide and celastrol in Tripterygium wilfordii, laying a foundation for further exploring the regulation mechanism of MCT gene on the terpenoid biosynthesis in Tripterygium wilfordii.

The commonly used traditional Chinese medicines Curcumae Rhizome (Ezhu) and Curcumae Radix (Yujin), are representatives of multi-plant sources. The relationship among the original source plant species is intricate. In this study, by using multivariate data analysis, volatile metabolites in rhizomes and radixes of source plants of Curcumae Longae rhizome (Jianghuang), Yujin and Ezhu in traditional Chinese medicine were compared and analyzed. The source plants included Curcuma longa, Curcuma kwangsuensis, Curcuma wenyujing and Curcuma phaeocaulis. The results indicated that:① volatile metabolites were similar in quality but variation in quantity for rhizomes and radixes origin from the same plant species; ② volatile metabolites of C. longa rhizomes showed bigger difference compared with others; ③ although common volatile metabolites were observed in rhizome of C. kwangsuensis, C. wenyujing and C. phaeocaulis, the difference among them were significant; and ④ significant differences were observed for the four kinds of radixes. Results in this study revealed the differences of the four source plants species, and similar metabolites in source plants of Curcumae Rhizome (Ezhu) and Curcumae Radix (Yujin) from the level of volatile metabolites. These results provided a reference for the clinical use of the three kinds of traditional Chinese medicine.