Chemical constituents of Malaysian Aquilaria crassna Pierre (gaharu)

Studies of Aquilaria crassna  Pierre from the leaves and barks had been divided into four  parts;   phytochemical  screening,  essential  oils,  chemical  constituents  and antimicrobial  activities.  Samples  were  extracted  using  three  solvents;  hexane, dichloromethane and  methanol. All   six  extracts;  three  leaves  and  three  barks  had underwent phytochemical screening to detect  the presence of secondary metabolites. Fresh samples of leaves and barks went through  hydrodistillation process using Dean­ Stark  apparatus  to obtain  essential  oil.  Isolation  of  chemical  compounds  had  been done using several chromatography techniques such as column  chromatography (CC), preparative  thin  layer  chromatography  (PTLC)  and  monitoring  with  thin   layer chromatography (TLC). Totally, seven pure compounds successively  isolated.  Four pure   compounds  isolated  from  leaves;  5-hydroxy- 7,4•  -dimethoxyflavone  (29)  and epifriedelanol   (30)  from  hexane  extract  while  squalene  (31)  and  5-hydroxy-7,4•  - dimethoxyflavone (29)   from  dichloromethane extract.  Further  extraction  on  barks yield   three   pure   compounds;    sec-nonacosyl   ester   (32),   5-hydroxy-7,4•  - dimethoxytlavone (29) and bis (2-ethylhexyl)  phthalate (33). Finally, crude extracts had been screened for antimicrobial activities towards four  bacteria. Results show that Staphylococcus aureus was the most susceptible bacteria to all six  extracts. Whilst, the least susceptible strain was Pseudomonas aeruginosa.