β-Patchoulene: Conversion from Patchouli Alcohol by Acid Catalysts and its In silico Anti-inflammatory Study

β-Patchoulene (β-PAE) is a tricyclic sesquiterpene which performed many potential bioactivities and can be found in patchouli oil but in very low concentration. This study aimed to obtained β-PAE in high concentration by conversion of patchouli alcohol (PA) in patchouli oil under acid catalyzed reaction. Patchouli oil was fractinated by vacuum distillation at 96 kPa to get the fraction with the highest PA content. H2SO4 and ZnCl2 were used respectively as homogeneous and heterogeneous acid catalysts in the conversion reaction of the selected fraction. Patchouli oil, the fractions and the products were analysed by using GC-MS and FTIR instruments. Moreover, the interaction of β-PAE to COX-2 protein was studied to understand the antiinflammation activity of β-PAE. The results showed that patchouli oil contains 25.3% of PA. The selected fraction which has the highest PA content (70.3%) was distilled at 151 - 152 oC. The application of ZnCl2 catalyst in conversion reaction did not succeed. In contrast, H2SO4 as a catalyst in acetic acid solvent succeeded in converting the overall fraction of PA to β-PAE. Furthermore, the molecular docking study of β-PAE against COX-2 enzyme showed van der Waals and alkyl-alkyl stacking interactions on ten amino acid residues. Keywords  β-patchoulene, molecular docking, patchouli oil, patchouli alcohol, sulphuric acid catalyst, conversion mechanism