Ase 100 system

The plant Trewia nudiflora L. was collected in Rajshahi, Bangladesh, in May 2006 and a voucher specimen (DACB 34427) was deposited at the Bangladesh National Herbarium. The air-dried powdered stem bark (1.1 kg) was subjected to accelerated solvent extraction using an ASE 100® system (Dionex, UK) successively with n-hexane, ethyl acetate and methanol. Operating conditions comprised of four static cycles (one cycle = 8 min); oven temperature 100 °C, flush volume 60 %, purge time 150 s, pressure 1400–1500 psi. The methanol extract was successively partitioned with n-hexane, ethyl acetate and butanol. The butanol phase was further fractionated by vacuum liquid chromatography using silica gel 60H (VWR International, UK). The fraction eluted with 35 % methanol in ethyle acetate was chromatographed on a C-18 silica column (10 g, Phenomenex, UK) using a Flash Master Personal® system (Biotage, UK). Elution with 100 % water, followed by gradual increases of acetone, yielded compound (2) (46 mg) as a light brown amorphous solid. Characterisation work was performed by a combination of mass spectrometry and ¹H and ¹³C nuclear magnetic resonance spectroscopy experiments, acquired on a ThermoFinnigan LCQ- Orbitrap and a JEOL- 400 Lambda Delta instrument, respectively.

The plants were separated into leaves and stems, dried at room temperature and ground in a Wiley mill. The extraction procedure was chosen on the basis of similar conditions previously reported (Ju and Howard, 2003 (link); Bergeron et al., 2005 (link)). Extractions were conducted using a Dionex ASE 100 system (Oakville, ON, Canada) with stainless steel vessels (66 mL) using 0.5 g of dry ground plant, and ~60 mL EtOH at 60°C and 1500 psi for 15 min. The extracts were dried using a vacuum evaporator (Eppendorf, Hauppauge, NY, USA).