Synthesis and biological evaluation of panaxatriol derivatives against myocardial ischemia/reperfusion injury in the rat.

Panaxatriol (PT) is a natural product derived from ginseng that possesses cardioprotective effects in isolated rat hearts. To develop more potent therapeutic agents against myocardial ischemia/reperfusion (MI/R) injury from natural products, a novel series of heterocycle ring-fused panaxatriol derivatives were designed and synthesized. In vitro results showed that approximately half of them exhibited increased cytoprotective activity compared with PT in a cardiomyocyte model of oxygen-glucose deprivation and reperfusion (OGD/R) injury. Furthermore, the in vitro activity of the representative derivative, compound 18, was also confirmed in a rat model of MI/R injury. In vivo results showed that 18 can markedly reduce myocardial infarction size, decrease circulating cardiac troponin I (cTnI) leakage, and alleviate cardiac tissue damage in the rats. Therefore, these findings provide the basis for further development of novel anti-MI/R injury agents.

[Synthesis and anti-tumor activity of ginsenoside Rh_2 caprylic acid monoester].

Ginsenoside Rh_2,firstly isolated from red ginseng,is protopanaxadiol type of steroidal saponin. Rh_2 possessed variety of activities,but bioavailability of oral administration Rh_2 was extremely low due to poor absorption. Moreover,ginsenoside Rh_2 exhibited toxicity on human normal cells. Therefore,to improve stronger anti-tumor activity and attenuate toxicity,it was essential to design and optimize chemical structure of ginsenoside Rh_2. Through n-octanoylchloride modifications,a novel ester derivative of ginsenoside Rh_2 named caprylic acid monoester of Rh_2( C-Rh_2) was designed and synthesized. Structure of novel ginsenoside derivative was identified by1 D and 2 D NMR,as well as ESI-MS analyses. Anti-tumor effect of C-Rh_2 was tested on H22 tumor bearing mice. C-Rh_2 displayed certain anti-tumor activities and exhibited less toxicity than Rh_2. In the present study,C-Rh_2 as ester form of ginsenoside Rh_2 showed better anti-tumor activity and less toxicity,but the specific mechanism needs further investigation.

Esterified Derivatives of Panaxadiol and Their Inhibitory Effect on HL-60, THP-1, and PC-3 Cell Lines.

Panaxadiol is a dammarane-type ginsenoside having high ginseng content. The 3-hydroxy group of panaxadiol (PD) was modified by fatty acids and diacids. The modified panax glycol had enhanced anticancer activity. Twelve PD derivatives were evaluated and purified by chemical synthesis, column chromatography, co-synthesis, and identification. The human leukemia cells THP-1, HL-60, and human prostate cancer cell lines PC-3 were evaluated; PD derivatives were tested and evaluated in vitro by MTT assay. The results showed that the antitumor activities of some derivatives on three tumor cell lines were better than those of PD.

Acylation of 25-hydroxyprotopanaxatriol with aromatic acids increases cytotoxicity.

20(R)-25-hydroxyprotopanaxadiol (25-OH-PPD) is a natural compound showing a variety of anti-tumor effects. In an attempt to search for a new anti-cancer compound with higher antitumor activities, we designed and synthesized a series of 25-OH-PPD derivatives. Cytotoxicity assay of these derivatives towards MCF-7, A549, U87, HO-8901, Hela cancer cell lines and normal IOSE144 cell lines were tested by MTT assay. Results showed that compared with compound 25-OH-PPD, Compounds 4, 5, 6, 10, 11 showed strong anticancer activity, and all compounds showed low toxicity or no toxicity for normal cells. In particular, compound 6 exhibited the best anti-tumor activity in all cancer cell lines (MCF-7, A549, U87, HO-8901, and Hela) with IC50 values of 5.04 µM, 1.36 µM, 3.24 µM, 3.47 µM, 4.57 µM, respectively. Among the five cell lines, all the compounds showed strong inhibition on A549 cells. Further studies showed that Compound 6 significantly inhibited the proliferation of A549 cells by inducing apoptosis. Our results indicate that Compound 6 is a potential anticancer inhibitor and provides a theoretical basis for further research.

Synthesis and In Vitro Anti-inflammatory Activity of C20 Epimeric Ocotillol-Type Triterpenes and Protopanaxadiol.

Ginseng is a perennial herb that contains various medicinal substances. The major active constituents of ginseng are ginsenosides, which have multifarious biological activities. Some pharmacological activities are closely dependent on the stereoisomers derived from the configuration at C20. In this study, the in vitro anti-inflammatory activity of C20 epimeric ocotillol-type triterpenes (2, 3, 9: , and 10: ) and protopanaxadiol [20(S/R)-protopanaxadiol] were investigated. Epimers 2: and 3: were prepared starting from 20(S)-protopanaxadiol. Epimers 9: and 10: were synthesized from 20(R)-3-acetylprotopanaxadiol (7: ). The anti-inflammatory activity of 2, 3, 9, 10: , 20(S)-protopanaxadiol, and 20(R)-protopanaxadiol was evaluated in cultured mouse macrophage RAW 264.7 cells. The MTT assay was used to measure the cytotoxicity. RAW 264.7 cells were stimulated by lipopolysaccharide to release the inflammatory mediators nitric oxide, prostaglandin E2, TNF-α, and interleukin-6 and anti-inflammatory mediator interleukin-10. The effect of the compounds on the overproduction of nitric oxide, prostaglandin E2, TNF-α, interleukin-6, and interleukin-10 was determined using Griess and ELISA methods. The results demonstrated that the in vitro anti-inflammatory activities of C20 epimeric ocotillol-type triterpenes and protopanaxadiol were different. Both the 20S-epimers (2: and 3: ) and 20R-epimers (9: and 10: ) inhibited the release of inflammatory mediator nitric oxide, while mainly the 20S-epimers inhibited the release of inflammatory mediator prostaglandin E2, and the 20R-epimers inhibited the release of inflammatory cytokine TNF-α. Both the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] and 20R-epimers [9, 10: , and 20(R)-protopanaxadiol] inhibited the release of inflammatory cytokine interleukin-6, but mainly the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] increased the release of anti-inflammatory mediator interleukin-10.

Synthesis of ginsenoside Re-based carbon dots applied for bioimaging and effective inhibition of cancer cells.

BACKGROUND: Fluorescent carbon-based nanomaterials have promising properties such as biosensing, cell imaging, tracing and drug delivery. However, carbon dots (CDs) with specific inherent biological functions have not been investigated. Ginsenosides are the components with multiple bioactivities found in plants of the genus Panax, which have attracted a lot of attention for their anticancer effect. MATERIALS AND METHODS: In this study, we prepared a kind of novel photoluminescent CDs from ginsenoside Re by one-step hydrothermal synthesis method. The conventional methods including transmission electron microscopy, Fourier transform infrared spectroscopy, HPLC and fluorescence spectrum were used for characterization of CDs. In vitro anticancer effect was investigated by cytotoxicity assay, flow cytometry and Western blot analysis. RESULTS: The as-prepared Re-CDs had an average diameter of 4.6±0.6 nm and excellent luminescent properties. Cellular uptake of Re-CDs was facilitated by their tiny nanosize, with evidence of their bright excitation-dependent fluorescent images. Compared with ginsenoside Re, the Re-CDs showed greater inhibition efficiency of cancer cell proliferation, with lower toxicity to the normal cells. The anticancer activity of Re-CDs was suggested to be associated with the generation of large amount of ROS and the caspase-3 related cell apoptosis. CONCLUSION: Hopefully, the dual functional Re-CDs, which could both exhibit bioimaging and anticancer effect, are expected to have great potential in future clinical applications.

Synthesis and evaluation of panaxatriol derivatives as Na+, K+-ATPase inhibitors.

Panaxatriol, a triterpene bearing a steroid-like structure similar to cardiac glycosides, was presumed to share the same bioactivity with cardiac glycosides, and may be a potential Na+, K+-ATPase inhibitor. In this paper, a series of panaxatriol derivatives were synthesized and evaluated for Na+, K+-ATPase inhibitory activities. The results of biological tests showed that more than half of the synthesized derivatives presented increased inhibitory activities compared with panaxatriol. Of these compounds, 13a with a 3, 4-seco skeleton showed the most potent inhibitory activity, which was equal to that of the standard drug digoxin. To understand the binding mode of the most active compound, molecular docking study of 13a with Na+, K+-ATPase was conducted. Therefore, 13a may serve as a new lead compound for the development of novel Na+, K+-ATPase inhibitors.

Production of Minor Ginenosides from Panax notoginseng by Microwave Processing Method and Evaluation of Their Blood-Enriching and Hemostatic Activity.

A green solvent extraction technology involving a microwave processing method was used to increase the content of minor ginsenosides from Panax notoginseng. This article aims to investigate the optimization of preparation of the minor ginsenosides by this microwave processing method using single-factor experiments and response surface methodology (RSM), and discuss the blood-enriching activity and hemostatic activity of the extract of microwave processed P. notoginseng (EMPN) The RSM for production of the minor ginsenosides was based on a three-factor and three-level Box-Behnken design. When the optimum conditions of microwave power, temperature and time were 495.03 W, 150.68 °C and 20.32 min, respectively, results predicted that the yield of total minor ginsenosides (Y9) would be 93.13%. The actual value of Y9 was very similar to the predicted value. In addition, the pharmacological results of EMPN in vivo showed that EMPN had the effect of enriching blood in N-acetylphenylhydrazine (APH) and cyclophosphamide (CTX)-induced blood deficient mice because of the increasing content of white blood cells (WBCs) and hemoglobin (HGB) in blood. Hemostatic activity in vitro of EMPN showed that it had significantly shortened the clotting time in PT testing (p < 0.05). The hemostatic effect of EMPN was mainly caused by its components of Rh4, 20(S)-Rg3 and 20(R)-Rg3. This microwave processing method is simple and suitable to mass-produce the minor ginsenosides from P. notoginseng.

Synthesis and pharmacokinetic characterization of a pH-sensitive polyethylene glycol ginsenoside CK (PEG-CK) conjugate.

The ginsenosides in Panax ginseng have vast structural and pharmacological efficacies. We covalently conjugated polyethylene glycol on the surface of CK (PEG-CK) through an acid-labile ester-linkage that showed increased solubility of CK. HPLC analysis showed that the release of CK was enhanced at acidic pH 5, whereas it was dramatically decreased at physiological pH 7.4. This might enhance the efficacy of CK.

Complete conversion of major protopanaxadiol ginsenosides to compound K by the combined use of α-L-arabinofuranosidase and ß-galactosidase from Caldicellulosiruptor saccharolyticus and ß-glucosidase from Sulfolobus acidocaldarius.

The ginsenoside compound K has pharmaceutical activities, including anti-tumor, anti-inflammatory, anti-allergic, and hepatoprotective effects. To increase the production of compound K, the α-L-arabinofuranoside-hydrolyzing α-L-arabinofuranosidase (CS-abf) and/or the α-L-arabinopyranoside-hydrolyzing ß-galactosidase from Caldicellulosiruptor saccharolyticus (CS-bgal) were mixed with the ß-D-glucopyranoside-hydrolyzing ß-glucosidase from Sulfolobus acidocaldarius (SA-bglu). The optimum conditions for the production of ginsenoside compound K from ginsenoside Rc or Rb2, or from major protopanaxadiol ginsenosides in ginseng root extract were determined to be pH 6.0 and 75°C with 8 mg ml⁻¹ ginsenoside Rc, 8 mg ml⁻¹ Rb2, or 10% (w/v) ginseng root extract; and 10.5 U ml⁻¹ CS-abf or CS-bgal supplemented with 4.5 U ml⁻¹ SA-bglu, or 10.5 U ml⁻¹ CS-abf and 10.5 U ml⁻¹ CS-bgal supplemented with 4.5 U ml⁻¹ SA-bglu, respectively. Under optimum conditions, ginsenosides Rc and Rb2, and major protopanaxadiol ginsenosides in ginseng root extract were completely converted to compound K after 12, 14, and 20 h, respectively, with the respective productivities of 388, 328, and 144 mg l⁻¹ h⁻¹. This is the first report of the complete conversion of major protopanaxadiol ginsenosides to compound K.

Optimization of the selective preparation of 20(R)-ginsenoside Rg3 catalyzed by d, l-tartaric acid using response surface methodology.

The optimization of the selective preparation of 20(R)-ginsenoside Rg3 converting protopanaxadiol type saponins (PPD saponins) by the commercially available d, l-tartaric acid was carried out using response surface methodology (RSM) based on a three-factor and six-level central composite design. The optimal 20(R)-ginsenoside Rg3 de% was predicted to be 94.52% in the combination of the factors (d, l-tartaric acid concentration 1.19mol/L, temperature 107.9°C and time 2.79h) through the canonical analysis with maximum responses. Under the optimum reaction conditions, the actual 20(R)-ginsenoside Rg3 de% was 96.49%. 20(R)-ginsenoside Rg3 (1) and 20(S)-ginsenoside Rg3 (2) were separated and identified by (1)H-NMR and (13)C-NMR. Therefore, the RSM was effective to optimize the preparation of 20(R)-ginsenoside Rg3 by converting PPD saponins using d, l-tartaric acid.

Isolation, synthesis and structures of cytotoxic ginsenoside derivatives.

Four known ginsenosides: ginsenoside-Rb1 (1), Rb3 (2), Rd (3) and Re (4) were isolated from the methanolic extract of the traditional Chinese medicine Panax ginseng C. A. Meyer. Further enzyme reactions and chemical modifications led us to obtain ginsenoside-M1 (5) and synthesize three novel mono-esters of ginsenoside-M1, ginsenoside-DM1 (6), PM1 (7) and SM1 (8) 30 - 50% of yield via a facile and green synthetic strategy. The structures were elucidated on the basis of extensive 1D- and 2DNMR, as well as high resolution ESI-TOF mass spectroscopic analyses. The isolated and synthetic compounds were tested in an anti-tumor bioassay, and compounds 5-8 showed considerable cytotoxicity (SRB) against several human cancer cell lines (breast cancer MCF-7, skin melanoma SK-MEL-2 and human ovarian carcinoma B16), but moderate effects on lung carcinoma COR-L23. The other ginsenosides showed no effects.