Preparation of the EtOH extract for preliminary assay
Dried rhizomes of Boesenbergia longiflora (5 kg) were pulverized and macerated with EtOH at room temperature, four times (6 L×4). The filtrate was then concentrated under vacuum using rotary evaporator. The yield of EtOH extract of Boesenbergia longiflora was found to be 562.5 g (11.3% w/w). The extract (539 g) was suspended in 95% methanol and then partitioned with hexane, and successively partitioned with CHCl3 and water. After that, the water layer was partitioned with ethyl acetate (EtOAc). Each partition was evaporated to dryness and resulting fractions of hexane, CHCl3, EtOAc and water. These fractions were evaluated for anti-NO production on LPS-induced NO release using RAW264.7 cells.