Ginsenoside Rg3 liposomes regulate tumor microenvironment for the treatment of triple negative breast cancer.

OBJECTIVE: To improve the solubility and targeting of Ginsenoside Rg3 (G-Rg3), in the current study, we constructed a novel targeting functional material folic acid -poly(2-ethyl-2-oxazoline)-cholesteryl methyl carbonate (FA-PEOz-CHMC, FPC) modified G-Rg3 liposomes (FPC-Rg3-L). METHODS: FPC was synthesized by using folic acid (FA) as a targeted head coupling with acid-activated poly(2-ethyl-2-oxazoline)-cholesteryl methyl carbonate. The inhibitory effects of the G-Rg3 preparations on mouse breast cancer cells (4T1) were investigated by CCK-8 assay. Paraffin sections of female BALB/c mice viscera were taken for hematoxylin-eosin (H&E) staining after continuous tail vein injection of G-Rg3 preparations. BALB/c mice bearing triple-negative breast cancer (TNBC) were used as animal models to investigate the inhibition of G-Rg3 preparations on tumor growth and improving quality of life. Transforming growth factor-ß1 (TGF-ß1) and α-smooth muscular actin (α-SMA) were used to investigate the expression of two fibrosis factors in tumor tissues by western blotting. RESULTS: Compared with G-Rg3 solution (Rg3-S) and Rg3-L, FPC-Rg3-L had a significant inhibitory effect on 4T1 cells (p < .01), and the half maximal inhibitory concentration (IC50) of FPC-Rg3-L was significantly lower (p < .01). The H&E results showed that the injection of FPC-Rg3-L and Rg3-S did not cause damage to the organs of mice. Compared with the control group, tumor growth was significantly inhibited in mice treated with FPC-Rg3-L and G-Rg3 solutions (p < .01). CONCLUSIONS: This study presents a new and safe treatment for TNBC, reduces the toxic and side effects of the drug, and provides a reference for the efficient use of Chinese herbal medicine components.

Effect of Gut Microbiota on the Metabolism of Chemical Constituents of Berberis kansuensis Extract Based on UHPLC-Orbitrap-MS Technique.

The dried stem bark of Berberis kansuensis is a commonly used Tibetan herbal medicine for the treatment of diabetes. Its main chemical components are alkaloids, such as berberine, magnoflorine and jatrorrhizine. However, the role of gut microbiota in the in vivo metabolism of these chemical components has not been fully elucidated. In this study, an ultra-high performance liquid chromatography method coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) technology was applied to detect and identify prototype components and metabolites in rat intestinal contents and serum samples after oral administration of a B. kansuensis extract. A total of 16 prototype components and 40 metabolites were identified. The primary metabolic pathways of the chemical components from B. kansuensis extract were demethylation, desaturation, deglycosylation, reduction, hydroxylation, and other conjugation reactions including sulfation, glucuronidation, glycosidation, and methylation. By comparing the differences of metabolites between diabetic and pseudo-germ-free diabetic rats, we found that the metabolic transformation of some chemical components in B. kansuensis extract such as bufotenin, ferulic acid 4-O-ß-D-glucopyranoside, magnoflorine, and 8-oxyberberine, was affected by the gut microbiota. The results revealed that the gut microbiota can affect the metabolic transformation of chemical constituents in B. kansuensis extract. These findings can enhance our understanding of the active ingredients of B. kansuensis extract and the key role of the gut microbiota on them.

Dihydroisocoumarins and Dihydroisoflavones from the Rhizomes of Dioscorea collettii with Cytotoxic Activity and Structural Revision of 2,2'-Oxybis(1,4-di-tert-butylbenzene).

The investigation of the constituents of the rhizomes of Dioscorea collettii afforded one new dihydroisocoumarin, named (-)-montroumarin (1a), along with five known compounds-montroumarin (1b), 1,1'-oxybis(2,4-di-tert-butylbenzene) (2), (3R)-3'-O-methylviolanone (3a), (3S)-3'-O-methylviolanone (3b), and (RS)-sativanone (4). Their structures were elucidated using extensive spectroscopic methods. To the best of our knowledge, compound 1a is a new enantiomer of compound 1b. The NMR data of compound 2 had been reported but its structure was erroneous. The structure of compound 2 was revised on the basis of a reinterpretation of its NMR data (1D and 2D) and the assignment of the 1H and 13C NMR data was given rightly for the first time. Compounds 3a-4, three dihydroisoflavones, were reported from the Dioscoreaceae family for the first time. The cytotoxic activities of all the compounds were tested against the NCI-H460 cell line. Two dihydroisocoumarins, compounds 1a and 1b, displayed moderate cytotoxic activities, while the other compounds showed no cytotoxicity.

The Therapeutic Effects and Mechanisms of Salidroside on Cardiovascular and Metabolic Diseases: An Updated Review.

The increasing incidence of metabolic and cardiovascular diseases has severely affected global human health and life safety. In recent years, some effective drugs with remarkable curative effects and few side effects found in natural compounds have attracted attention. Salidroside (SAL), a phenylpropane glycoside, is the main active ingredient of the plateau plant Rhodiola. So far, many animal experiments proved that SAL has good biological activity against some metabolic and cardiovascular diseases. However, most of these reports are scattered. This review systematically summarizes the pharmacological progress of SAL in the treatment of several metabolic (e. g., diabetes and non-alcoholic fatty liver disease) and cardiovascular (e. g., atherosclerosis) diseases in a timely manner to promote the clinical application and basic research of SAL. Accumulating evidence proves that SAL has beneficial effects on these diseases. It can improve glucose tolerance, insulin sensitivity, and ß-cell and liver functions, and inhibit adipogenesis, inflammation and oxidative stress. Overall, SAL may be a valuable and potential drug candidate for the treatment of metabolic and cardiovascular diseases. However, more studies especially clinical trials are needed to further confirm its therapeutic effects and molecular mechanisms.

Traditional Tibetan Medicine in Cancer Therapy by Targeting Apoptosis Pathways.

Cancer is a leading cause of death around the world. Apoptosis, one of the pathways of programmed cell death, is a promising target for cancer therapy. Traditional Tibetan medicine (TTM) has been used by Tibetan people for thousands of years, and many TTMs have been proven to be effective in the treatment of cancer. This paper summarized the medicinal plants with anticancer activity in the Tibetan traditional system of medicine by searching for Tibetan medicine monographs and drug standards and reviewing modern research literatures. Forty species were found to be effective in treating cancer. More importantly, some TTMs (e.g., Ophiocordyceps sinensis, Phyllanthus emblica L. and Rhodiola kirilowii (Regel) Maxim.) and their active ingredients (e.g., cordycepin, salidroside, and gallic acid) have been reported to possess anticancer activity by targeting some apoptosis pathways in cancer, such as Bcl-2/Bax, caspases, PI3K/Akt, JAK2/STAT3, MAPK, and AMPK. These herbs and natural compounds would be potential drug candidates for the treatment of cancer.

1H NMR-Based Metabolomics Coupled With Molecular Docking Reveal the Anti-Diabetic Effects and Potential Active Components of Berberis vernae on Type 2 Diabetic Rats.

The dried stem bark of Berberis vernae C.K.Schneid., known as "Xiao-bo-pi" in Chinese, is a representative anti-diabetic herb in traditional Tibetan medical system. However, its anti-diabetic mechanisms and active components remain unclear. In this study, 1H NMR-based metabolomics, biochemistry assay, molecular docking, and network analysis were integrated to evaluate the anti-diabetic effects of B. vernae extract on type 2 diabetic rats, and to explore its active components and underlying mechanisms. Diabetes was induced by high-fat diet and streptozotocin. After 30 days of treatment, B. vernae extract significantly decreased the serum levels of fasting blood glucose, insulin, insulin resistance index, glycated serum protein, TNF-α, IL-1ß, and IL-6, whereas significantly increased the serum levels of insulin sensitivity index in type 2 diabetic rats. A total of 28 endogenous metabolites were identified by 1H NMR-based metabolomics, of which 9 metabolites that were changed by diabetes were significantly reversed by B. vernae extract. The constructed compound-protein-metabolite-disease (CPMD) interaction network revealed the correlation between chemical constituents, target proteins, differential metabolites, and type 2 diabetes. Ferulic acid 4-O-ß-D-glucopyranoside, bufotenidine, jatrorrhizine, and berberine showed good hit rates for both the 30 disease-related proteins and 14 differential metabolites-related proteins, indicating that these four compounds might be the active ingredients of B. vernae against type 2 diabetes. Moreover, pathway analysis revealed that the anti-diabetic mechanisms of B. vernae might be related to its regulation of several metabolic pathways (e.g., butanoate metabolism) and disease-related signal pathways (e.g., adipocytokine signaling pathway). In summary, B. vernae exerts a significant anti-diabetic effect and has potential as a drug candidate for the treatment of type 2 diabetes.

[Effects of gut microbiota on five absorbed components of Berberis kansuensis in rat serum by HPLC-QqQ-MS].

To elucidate the absorption and metabolism of alkaloids in Berberis kansuensis in vivo, a high performance liquid chromatography-triple quadrupole mass spectrometry(HPLC-QqQ-MS) method was developed to qualitatively and quantitatively analyze the absorption components in rat serum in multiple-reaction monitoring mode. The mobile phase consisted of 0.1% formic acid and acetonitrile with a gradient elution mode. In addition, to investigate the effects of gut microbiota on five absorbed components of B. kansuensis in rat serum, diabetic rat and pseudo germ-free diabetic rat models were established, and partial least squares discriminant analysis and One-way ANOVA were used to study the content differences of five components among different groups. In this study, a HPLC-QqQ-MS method for quantitative analysis of five components in rat serum after oral administration of B. kansuensis was established for the first time. It was found that there were differences in the five constituents in rat serum between different groups. By comparing the normal group with the diabetic model group, we found that the absorption and metabolism capacities of berberine and magnoflorine were different under the health and pathological conditions. It was also found that the serum levels of berberine, magnoflorine and jatrorrhizine in pseudo germ-free diabetic rats were significantly lower than those in diabetic rats, indicating that gut microbiota plays an important role in the metabolism of alkaloids of B. kansuensis in vivo. These results provide a good reference for clarifying the active ingredients of B. kansuensis in the treatment of diabetes.

Hyaluronic acid-coated nanostructured lipid carriers for loading multiple traditional Chinese medicine components for liver cancer treatment.

This study aimed to develop hyaluronic acid (HA)-coated nanostructured lipid carriers (NLC) loaded simultaneously with oleanolic acid (OA), ursolic acid (UA) and Ginsenoside Rg3 (Rg3), prepared by electrostatic attraction for delivering OA, UA and Rg3 (OUR), termed HA-OUR-NLC, to tumors over expressing cluster determinant 44(CD44). The dialysis method was used to assess the in vitro release of OUR. Parameters such as pharmacokinetics, biodistribution, fluorescence in vivo endo-microscopy (FIVE), optical in vivo imaging (OIVI) data, and in vivo antitumor effects were evaluated. The results showed a total drug loading rate of 8.76±0.95% for the optimized HA-OUR-NLC; total encapsulation efficiency was 45.67±1.14%; particle size was 165.15±3.84%; polydispersity index was 0.227±0.01; zeta potential was -22.87±0.97 mV. Drug release followed the Higuchi kinetics. Pharmacokinetics and tissue distribution, as well as antitumor effects were evaluated in nude mice in vivo. HA-OUR-NLC were better tolerated, with increased antitumor activity compared with 5-Fu. In in vivo optical imaging, we use 1,1'-dioctadecyl-3,3,3',3'-tetramethy(DiR) as a fluorescent dye to label the NLC. The DiR-OUR-NLC group showed bright systemic signals, while the tumor site was weak. The present findings indicated that HA-OUR-NLC accumulated in the tumor site, prolonging OUR duration in the circulation and enhancing tumoral concentrations. Therefore, NLC prepared by electrostatic attraction constitute a good system for delivering OUR to tumors.

Zearalenone Removal from Corn Oil by an Enzymatic Strategy.

The estrogen-like mycotoxin zearalenone (ZEN) is one of the most widely distributed contaminants especially in maize and its commodities, such as corn oil. ZEN degrading enzymes possess the potential for counteracting the negative effect of ZEN and its associated high safety risk in corn oil. Herein, we targeted enhancing the secretion of ZEN degrading enzyme by Pichia pastoris through constructing an expression plasmid containing three optimized expression cassettes of zlhy-6 codon and signal peptides. Further, we explored various parameters of enzymatic detoxification in neutralized oil and analyzed tocopherols and sterols losses in the corn oil. In addition, the distribution of degraded products was demonstrated as well by Agilent 6510 Quadrupole Time-of-Flight mass spectrometry. P. pastoris GSZ with the glucoamylase signal was observed with the highest ZLHY-6 secretion yield of 0.39 mg/mL. During the refining of corn oil, ZEN in the crude oil was reduced from 1257.3 to 13 µg/kg (3.69% residual) after neutralization and enzymatic detoxification. Compared with the neutralized oil, no significant difference in the total tocopherols and sterols contents was detected after enzymatic detoxification. Finally, the degraded products were found to be entirely eliminated by washing. This study presents an enzymatic strategy for efficient and safe ZEN removal with relatively low nutrient loss, which provides an important basis for further application of enzymatic ZEN elimination in the industrial process of corn oil production.

Chemotaxonomic studies of 12 Dioscorea species from China by UHPLC-QTOF-MS/MS analysis.

INTRODUCTION: Dioscorea species, which contain abundant steroidal saponins, have been used as folk medicines or raw materials to synthesise steroid drugs. OBJECTIVE: To establish a rapid chemotaxonomic method that will comprehensively resolve confusions about genetic relationships of genus Dioscorea. METHODS: A comprehensive strategy using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) was firstly proposed to evaluate the chemotaxonomy of 12 species (27 taxa) from China by hierarchical cluster analysis (HCA) based on the variations of the identified metabolites. RESULTS: Twenty-eight secondary metabolites (mainly steroidal saponins) were identified. The MSn fragmentation patterns of DA (a new acetylated steroidal saponin at C-7 position) were firstly reported. Moreover, eight major steroidal saponins were further quantified simultaneously by UPLC-QTOF-MS method. According to HCA results, D. bulbifera L. was distinguished with species of sect. Stenophora Uline for pennogenin-type steroidal saponins. Dioscorea zingiberensis exhibited far distance from other members of sect. Stenophora Uline for two unique saponins. Dioscorea banzhuana may be reclassified into sect. Stenophora. Dioscorea nipponica subsp. rosthornii and D. collettii var. hypoglauca might be separated from their original subspecies/varieties as new species, respectively. CONCLUSION: The chemotaxonomic method was successfully applied in the study of genetic relationships of Dioscorea species. This study not only enhanced the understanding of chemical constituents, but also laid basic theoretical foundations for the rational utilisation and chemotaxonomy of genus Dioscorea.

Two new alkaloids from Portulaca oleracea L. and their bioactivities.

Two new indole alkaloids, identified as (E)-1-(5,6-dihydroxy-1H-indol-1-yl)-3-(4-hydroxyphenyl)prop-2-en-1-one, named oleraindole A (1), and (E)-1-(5,6-dihydroxy-1H-indol-1-yl)-3-(4-hydroxy-3-methoxyphenyl)prop-2-en-1-one, named oleraindole B (2), together with five known indole alkaloids, (-)-neoechinulin A (3), neoechinulin D (4), isoechinulin A (5), MT-6 (6) and echinulin (7) were isolated from the aqueous extract of Portulaca oleracea L. for the first time, using various chromatographic techniques. The structures of seven alkaloids were elucidated by the 1D and 2D NMR and HR-ESI-TOF-MS spectroscopic methods. Oleraindole A (1) and oleraindole B (2) exhibited a relatively high anticholinesterase activity with IC50 values of 55.12 ±â€¯0.20 µΜ and 46.76 ±â€¯0.08 µM, and antioxidant activities with the IC50 values of 16.20 ±â€¯0.11 µM and 13.88 ±â€¯0.06 µM among seven alkaloids.

Dioscin-6'-O-acetate inhibits lung cancer cell proliferation via inducing cell cycle arrest and caspase-dependent apoptosis.

BACKGROUND: Lung cancer is the leading cause of global cancer-related mortality. Dioscin-6'-O-acetate (DA), a novel natural steroidal saponin, was firstly isolated from the rhizomes of Dioscorea althaeoides R. Knuth. Until now, there were no studies on its pharmacological activities. PURPOSE: Here, we investigated the growth inhibitory effect and explored the underlying molecular mechanisms of DA against lung cancer cells. METHODS/STUDY DESIGNS: NSCLC H460, H1299, H520 cells and SCLC H446 cells were treated with DA. To display the cytotoxic effects and possible mechanism of DA on these cells, MTT assay, flow cytometry and western blot analysis were carried out. RESULTS: Our results showed that DA exerted strong anti-proliferative activity against lung cancer cells in a concentration- and time-dependent manner. Flow cytometry demonstrated DA induced the cell cycle arrest at S-phase (NCI-H460, NCI-H1299, NCI-H520) or G1-phase (NCI-H446), caused cellular apoptosis, generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential. Western blotting analysis showed DA treatment increased the levels of caspase 3, 8, 9, Bax, p21, p53, phosphorylated JNK and p38 MAPK and markedly decreased the expression of Bcl-2, p-ERK, p-PI3K, p-AKT and NF-κB. Blockade of caspases with Z-VAD-FMK converted apoptosis-related proteins. Suppression of p53 with pifithrin-α (PFT) attenuated cell cycle-related protein. Inhibition of ROS with N-acetyl-cysteine (NAC) adjusted apoptosis-related proteins and phosphorylated MAPK and PI3K, as well as NF-κB. CONCLUSION: Overall, our study indicated that DA suppressed lung cancer cells proliferation via inducing cell-cycle arrest and enhancing caspase-dependent apoptosis, at least partly, through ROS-mediated PI3K/AKT, MAPK and NF-κB signaling pathways.

Maternal dietary supplementation of arginine increases the ratio of total cloned piglets born to total transferred cloned embryos by improving the pregnancy rate of recipient sows.

The extremely low full-term developmental efficiency of cloned pig embryos limits the practical application of pig cloning techniques. Maternal dietary supplementation of the nutritionally important amino acid, arginine, can enhance prenatal developmental rate of in vivo fertilization-derived pig embryos. It was hypothesized that maternal dietary addition of arginine can also improve the developmental capacity of cloned pig embryos. To test this hypothesis, there was a comparison of the reproductive performance between recipient sows fed an L-arginine-supplemented diet (L-Arg group) and those fed the control diet (control group). There was a subsequent comparison of the developmental indexes of cloned piglets farrowed in the L-Arg and control groups of surrogate sows. Dietary supplementation of L-arginine during gestation days 14-75 increased the plasma concentrations of arginine and arginine metabolites, including nitric oxide, spermidine, and putrescine in recipient sows of transferred cloned pig embryos. Although maternal arginine addition did not affect the birth weight and placental development indexes of newborn cloned piglets, it significantly increased the ratio of total cloned piglets born to total transferred cloned pig embryos by increasing the pregnancy rate of recipient sows. The results of this study suggest that nutritional management of recipient sows is an effective approach to improve the developmental rate of cloned pig embryos.

The genus Polygonatum: A review of ethnopharmacology, phytochemistry and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Polygonatum (Asparagaceae) comprises 71 species distributed throughout the temperate Northern Hemisphere. The medicinal plants of Polygonatum have been traditionally used as tonics in China, India, Pakistan, Iran and Japan, and have been demonstrated to be highly effective in clinical practice for treating age-related diseases, diabetes, lung diseases, fatigue, feebleness and indigestion. AIM OF THE REVIEW: This paper aims to provide the links among traditional uses, chemical constituents, pharmacological effects and toxicity to support their therapeutic potential and uncover opportunities for future research. MATERIALS AND METHODS: The relevant information on the genus Polygonatum was gathered from scientific databases (Google Scholar, Web of Science, SciFinder, ScienceDirect, ACS Publications, PubMed, Wiley Online Library, CNKI). Information was also obtained from online databases, books, Ph.D. dissertations and M.Sc. theses. The literature cited in this review dates from 1917 to June 2017. RESULTS: At least 37 species and 1 variety of Polygonatum plants have been used as traditional medicine and functional food. The major chemical constituents of Polygonatum plants are steroidal saponins, triterpenoid saponins, homoisoflavanones, polysaccharides and lectins. A putative biosynthetic pathway of steroidal saponins and triterpenoid saponins has been established based on the compounds isolated from Polygonatum plants. The crude extracts and certain pure compounds from Polygonatum plants have shown a wide range of pharmacological effects such as anti-aging, anti-diabetic, anti-fatigue, and anticancer effects. The rhizomes of Polygonatum plants have a low degree of toxicity after processing. CONCLUSIONS: Based on this review, some traditional uses of Polygonatum species have been confirmed by pharmacological studies, such as its anti-osteoporosis, neuroprotective, immunomodulatory, anti-diabetic and anti-fatigue effects. Most of the pharmacological effects of this genus can be attributed to its polysaccharides, saponins and lectins. However, to clarify the chemical differences that lead to the different traditional uses between "Huangjing" (derived from P. sibiricum, P. kingianum, P. cyrtonema) and "Yuzhu" (derived from P. odoratum), a systematic comparison of the small molecule compositions and polysaccharides of these four species is needed. In addition to these four species, other locally used medicinal Polygonatum species should be the subject of research, and the chemical and pharmacological relationships of these species should be investigated to expand the medicinal resources and standardize the use of Polygonatum species.

Novel phenanthrene and isocoumarin from the rhizomes of Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting (Dioscoreaceae).

The investigation of the constituents in the rhizomes of Dioscorea nipponica Makino subsp. rosthornii (Prain et Burkill) C. T. Ting afforded one new phenanthrene 2,2',7,7'-tetramethoxy-[1,1'-biphenanthrene]-4,4',6,6'-tetrol (7) and one new isocoumarin diorosthornoumarin (8), together with 16 known compounds (1-6 and 9-18). Their structures were established on the basis of extensive spectroscopic evidences (IR, HR-ESI-MS, NMR and optical rotation), as well as comparison with literature values. All the compounds 1-18 were firstly isolated from Dioscorea nipponica Makino subsp. Rosthornii (Prain et Burkill) C. T. Ting, and compound 9 was firstly obtained as a natural product from plants, while the compounds 11 and 14 were obtained from both the genus Dioscorea and the family Dioscoreaceae for the first time. Moreover, the antitumor activities of the compounds were tested against lung carcinoma NCI-H460 cell line. Compound 12, 13, 15 and 16 showed significant cytotoxic activities, whereas 7 displayed moderate cytotoxicity.

Chemical Composition and Bioactivities of Two Common Chaenomeles Fruits in China: Chaenomeles speciosa and Chaenomeles sinensis.

Contents of total flavonoids, total phenolics, total triterpenes, total condensed tannin and total saponins in peels, flesh and endocarps of Chaenomeles speciosa (CSP) and Chaenomeles sinensis (CSS) were determined by colorimetric method, while 5 phenolics (vanillic, gallic, chlorogenic, ferulic and p-coumaric acids), 2 triterpenes (oleanolic and ursolic acids), and 3 flavonoids (rutin, catechin and epicatechin) were identified and quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and HPLC, and antioxidant and α-glucosidase inhibitory activities of them also were evaluated as well as their digestive characteristics. In the correlation analysis, total phenolics, vanillic acid, catechin, ursolic acid and oleanolic acid all contribute to DPPH(·) scavenge capacity, gallic acid contributes to total ferric reducing antioxidant power, while total triterpenes, total saponins, chlorogenic acid and ferullic acid contribute to α-glucosidase inhibitory activity. In the principal component analysis, endocarps of CSP and CSS both show better quality than their peels and flesh, respectively. In vitro digestion can increase contents of total flavonoids, total condensed tannin and total saponins, while contents of total phenolics and total triterpenes decreased greatly. Our study would contribute to the full use of discarded parts of the 2 Chaenomeles and be helpful to establish a good foundation for further research of CSP and CSS.

Enhancing Biosynthesis of a Ginsenoside Precursor by Self-Assembly of Two Key Enzymes in Pichia pastoris.

Ginsenosides from the edible and medicinal plant ginseng have demonstrated various pharmacological activities. However, producing ginsenoside efficiently remains a challenge. Engineering metabolic pathways through protein assembly in yeast is a promising way for ginsenoside production. In the biosynthetic pathway of ginsenosides, dammarenediol-II synthase and squalene epoxidase are two key enzymes that determine the production rate of the dammarane-type ginsenoside precursor dammarenediol-II. In this work, a strategy to enhance the biosynthesis of dammarenediol-II in Pichia pastoris was developed by the self-assembly of the two key enzymes via protein-protein interaction. After being modified by interacting proteins, the two enzymes were successfully co-localized, resulting in a 2.1-fold enhancement in dammarenediol-II yields.

A sensitive analysis method for 7 diterpenoids in rat plasma by liquid chromatography-electrospray ionization mass spectrometry and its application to pharmacokinetic study of Isodon serra extract.

A simple and sensitive LC-MS/MS method has been developed and validated for the identification and quantification of epinodosin, epinodosinol, nodosin, oridonin, lasiokariurinol, lasiokaurin and rabdoternin A in rat plasma using sulfamethoxazole as the internal standard. The plasma sample pre-treatment consisted of a liquid-liquid extraction. Chromatographic separation was achieved on a C18 column with linear gradient elution using water and methanol, which were both acidified with 0.1% formic acid, at a flow rate of 0.7 mL/min. A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source. A novel multi-determination-periods program was executed to achieve a higher sensitivity by setting five scanning periods. The method presented here utilizes a novel determination strategy, enabling the application of positive and negative ESI-MS in a single run. The optimized mass transition ion-pairs (m/z) for quantitation were 361.2/287.1 for epinodosin, 382.3/347.3 for epinodosinol, 363.3/281.2 for nodosin, 365.3/347.3 for oridonin, 407.3/329.1 for lasiokariurinol, 405.2/59.0 for lasiokaurin, 363.2/283.1 for rabdoternin A and 254.1/156.0 for IS. The total run time was 20.50 min (including 5 min equilibration time) between injections. The specificity, linearity, accuracy, precision, recovery, matrix effect and several validation results demonstrate that this method is sensitive, specific and reliable. The proposed method was further applied to investigate the pharmacokinetics of all analytes after a single oral administration of Isodon serra extract to rats.