An Integrated Strategy Based on 10-DAB Extraction and In Situ Whole-Cell Biotransformation of Renewable Taxus Needles to Produce Baccatin III

Baccatin III is a crucial precursor in the biosynthesis pathway of paclitaxel. Its main sources are extraction from Taxus or chemical synthesis using 10-deacetylbaccatin III (10-DAB) as substrate. However, these preparation approaches exhibit serious limitations, including the low content of baccatin III in Taxus and the complicated steps of chemical synthesis. Heterologous expression of 10-deacetylbaccatin III-10-O-acetyltransferase (TcDBAT) in microbial strains for biotransformation of 10-DAB is a promising alternative strategy for baccatin III production. Here, the promotion effects of glycerol supply and slightly acidic conditions with a low-temperature on the catalysis of recombinant TcDBAT strain were clarified using 10-DAB as substrate. Taxus needles is renewable and the content of 10-DAB is relatively high, it can be used as an effective source of the catalytic substrate 10-DAB. Baccatin III was synthesized by integrating the extraction of 10-DAB from renewable Taxus needles and in situ whole-cell catalysis in this study. 40 g/L needles were converted into 20.66 mg/L baccatin III by optimizing and establishing a whole-cell catalytic bioprocess. The method used in this study can shorten the production process of Taxus extraction for baccatin III synthesis and provide a reliable strategy for the efficient production of baccatin III by recombinant strains and the improvement of resource utilization rate of Taxus needles.

Analgesic effect of electroacupuncture on paclitaxel-induced neuropathic pain via spinal opioidergic and adrenergic mechanisms in mice

This study was designed to determine the antinociceptive effect and related neuronal mechanism of electroacupuncture (EA) on paclitaxel (PTX)-induced neuropathic pain in mice. PTX (4 mg/kg, i.p.) was administered once a day for 5 consecutive days to induce neuropathic pain. EA stimulation (2 mA, 2 Hz, 30 min) was applied at the ST36 acupoint bilaterally once in every 2 days. Repeated EA stimulation significantly attenuated PTX-induced mechanical allodynia and thermal hyperalgesia. In a separate set of experiment, the antinociceptive effect of a single EA stimulation 8 days after PTX treatment was reduced by intrathecal pretreatment with naloxone (opioid receptor antagonist), idazoxan (alpha2-adrenoceptor antagonist) or propranolol (beta-adrenoceptor antagonist), but not prazosin (alpha1-adrenoceptor antagonist). Moreover, EA remarkably suppressed the PTX-enhanced phosphorylation of the NMDA receptor NR2B subunit in the spinal dorsal horn, and intrathecal pretreatment of naloxone, idazoxan (IDA) or propranolol blocked the effect of EA. In conclusion, EA stimulation at the ST36 acupoint significantly diminished PTX-induced neuropathic pain in mice via the mediation of spinal opioid receptor, alpha2- and beta-adrenoceptors.

Antitumor effect of water decoctions of taxus cuspidate on pancreatic cancer

The Taxus cuspidate has been used as a traditional Chinese medicinal herb and considered to affect various physiological functions in the body for thousands of years. As we know that taxol isolated from the Taxus cuspidate has been approved for the treatment of ovarian cancer, it has also shown its antitumor abilities against other kinds of cancers. But the antitumor activity of other components which are free of paclitaxel and hydrophilic paclitaxel derivatives from Taxus cuspidate has not been fully understood. In this study, we investigated the effect of the water decoctions from the leaves of Taxus cuspidate on pancreatic cancer cell proliferation and the potential mechanism(s); though its antitumor activity and mechanism in vitro remain to be elucidated, the water soluble constituents from Taxus cuspidate could be used in clinical for cancer patients.

Preparation, characterization, and antitumor activities of folate-decorated docetaxel-loaded human serum albumin nanoparticles

CONTEXT

Docetaxel is now a major antitumor drug in clinical use for the treatment of a variety of tumors. The ethanol/Tween 80 solvent required in the formulation to increase the docetaxel solubility is at least partly responsible for the hypersensitivity reaction, decreased uptake by tumor tissue, and increased exposure to other body compartments.

OBJECTIVE

The present study was aimed at developing hydrosoluble DTX-FA-HSANPs targeting tumor cells and to investigate antitumor activities of the nanoparticles.

MATERIALS AND METHODS

The DTX-HSANPs were prepared using a desolvation technique and the carboxylic groups of NHS-folate were conjugated with the amino groups of the human serum albumin nanoparticles, and studied their size and zeta potential, drug loading efficiency, surface morphology, release properties in vitro, and antitumor activities.

RESULTS

The spherical nanoparticles obtained were negatively charged with a zeta potential of about -30 mV and characterized around 150 nm with a narrow size distribution. Drug loading efficiency was approximately 17.2%. The folate-decorated nanoparticles targeted a human hepatoma cell line effectively. The in vitro drug release of DTX-FA-HSANPs in the first 96 h corresponded with the following equation: Q = 18.87851 - 0.13866t + 0.21276t² - 0.00704t³ + 0.0000847854t⁴ - 0.00000034991t⁵ (R² = 0.98155). Moreover, the in vitro antitumor activities of DTX-FA-HSANPs were close to the activities of the positive control (docetaxel). The in vivo inhibition ratios of DTX-FA-HSANPs and docetaxel were 66.2% and 59.5%, respectively, at a dose of 5 mg/kg.

DISCUSSION AND CONCLUSION

In light of the observed antitumor activities, it would be of considerable interest to collect sufficient data for the clinical application of docetaxel-loaded nanoparticles.

In Vitro Investigation of Anti-Diabetic Effect of Taxus cuspidate Extracts by Ultrasound Assisted Method

Extracting active components from Chinese medicinal herbs efficiently is a key step in the investigation of their pharmacological effects and modes of action. In this project, we compared the ultrasound-assisted method and the conventional solvent method for extracting the active compound of Taxus cuspidate (dong bei hong dou shan). Through the analysis of various extractions with a quadruple time-of-fight (Q-TOF) LC/MS, we demonstrated that the ultrasound-assisted method reduced solvent consumption and had shorter extraction time, while the extraction yields of the active compound (taxol) were equivalent to or even higher than those obtained with the conventional solvent extraction method. Through the comparison of Taxus cuspidate extracts (TCEs) with different concentrations of acetone and ethanol, we proved that 50% ethanol was an optimal solvent for extracting taxol from Taxus cuspidate. Based on traditional Chinese medicine (TCM) literature, we further determined whether TCEs possess antidiabetic effects by testing glucose uptake in 3T3-L1 adipocytes treated with TCEs from Taxus cuspidate bark and twigs under insulin stimulation (100 nM). The results showed that neither taxol (10 μg/ml) nor TCEs (1 and 0.1 mg/ml) changed glucose uptake significantly compared with insulin alone. This study demonstrated that the ultrasound-assisted method with 50% ethanol is a highly efficient approach for extracting Taxus cuspidate, which may be applicable for extraction of other Chinese medicinal herbs. Extracts of Taxus cuspidate bark and twigs had no effect on insulin stimulated-glucose uptake in vitro. This result conflicts with the description in TCM literature. Further in vivo study to clarify Taxus cuspidate's metabolic actions is necessary.