Fermentative production and direct extraction of (-)-α-bisabolol in metabolically engineered Escherichia coli.

BACKGROUND: (-)-α-Bisabolol, also known as levomenol, is an unsaturated sesquiterpene alcohol that has mainly been used in pharmaceutical and cosmetic products due to its anti-inflammatory and skin-soothing properties. (-)-α-Bisabolol is currently manufactured mainly by steam-distillation of the essential oils extracted from the Brazilian candeia tree that is under threat because its natural habitat is constantly shrinking. Therefore, microbial production of (-)-α-bisabolol plays a key role in the development of its sustainable production from renewable feedstock. RESULTS: Here, we created an Escherichia coli strain producing (-)-α-bisabolol at high titer and developed an in situ extraction method of (-)-α-bisabolol, using natural vegetable oils. We expressed a recently identified (-)-α-bisabolol synthase isolated from German chamomile (Matricaria recutita) (titer: 3 mg/L), converted the acetyl-CoA to mevalonate, using the biosynthetic mevalonate pathway (12.8 mg/L), and overexpressed farnesyl diphosphate synthase to efficiently supply the (-)-α-bisabolol precursor farnesyl diphosphate. Combinatorial expression of the exogenous mevalonate pathway and farnesyl diphosphate synthase enabled a dramatic increase in (-)-α-bisabolol production in the shake flask culture (80 mg/L) and 5 L bioreactor culture (342 mg/L) of engineered E. coli harboring (-)-α-bisabolol synthase. Fed-batch fermentation using a 50 L fermenter was conducted after optimizing culture conditions, resulting in efficient (-)-α-bisabolol production with a titer of 9.1 g/L. Moreover, a green, downstream extraction process using vegetable oils was developed for in situ extraction of (-)-α-bisabolol during fermentation and showed high yield recovery (>98%). CONCLUSIONS: The engineered E. coli strains and economically viable extraction process developed in this study will serve as promising platforms for further development of microbial production of (-)-α-bisabolol at large scale.

The efficacy and safety of clopidogrel resinate as a novel polymeric salt form of clopidogrel.

A novel polymeric salt of clopidogrel, clopidogrel resinate, was prepared as a anticoagulant drug. To prove the feasibility as a new active substance, clopidogrel resinate was evaluated for its efficacy and safety. In accelerated stability tests, the clopidogrel resinate tablet (Pregrel) showed less brown discoloration and fewer impurities than the clopidogrel bisulfate tablets under open and closed conditions. In toxicity tests, no deaths occurred after a single dose of up to 2000 mg/kg/day and 13-week repeated doses of up to 625 mg/kg/day in rats without abnormal symptoms compared to clopidogrel bisulfate. When clopidogrel resinate was treated onto Caco-2 cell monolayers, clopidogrel, but not the resin, permeated across the cells with a hight permeation coefficient (Papp) of 13.5 +/- 1.13 x 10(-6) cm/sec. Clopidogrel resinate and clopidogrel bisulfate showed similar pharmacokinetics following oral administration to beagle dogs. A single oral administration of clopidogrel resinate dose-dependently inhibited ADP-induced ex vivo aggregation up to 30 mg/kg in rats. In conclusion, clopidogrel resinate was proved to be an efficient and safe polymeric salt as a candidate for a new clopidogrel salt.

Oxaliplatin, 5-FU, folinic acid as first-line palliative chemotherapy in elderly patients with metastatic or recurrent gastric cancer.

PURPOSE: We investigated the efficacy and safety of a combination of oxaliplatin, 5-fluorouracil (5-FU), and folinic acid (FA) as first-line palliative chemotherapy for elderly patients with metastatic or recurrent gastric cancer. MATERIALS AND METHODS: The study patients were chemotherapy-naïve patients (> 65 years old) with histologically confirmed, metastatic or recurrent gastric cancer. Chemotherapy consisted of oxaliplatin 100 mg/m(2) and FA 100 mg/m(2) (2-hour infusion), and then 5-FU 2400 mg/m(2) (46-hour continuous infusion) every 2 weeks. RESULTS: A total of 37 patients were studied between April 2004 and October 2006. Of the 34 evaluable patients, none achieved a complete response (CR) and 14 achieved a partial response (PR), resulting in an overall response rate of 41.2%. The median time to progression (TTP) was 5.7 months (95% CI: 4.2~6.3 months) and the median overall survival (OS) was 9.8 months (95% CI: 4.4~12.0 months). The main hematologic toxicities were anemia and neutropenia, which were observed in 56.7% and 32.4% of the patients, respectively. Grade 3/4 neutropenia was observed in 8.1% of the patients. None of the patients experienced febrile neutropenia. Peripheral neuropathy occurred in 35.1% of the patients and all were grade 1/2. CONCLUSION: This oxaliplatin/5-FU/FA regimen showed good efficacy and an acceptable toxicity profile in elderly patients with metastatic or recurrent gastric cancer.