Development of Patchouli Extraction with Quality Control and Isolation of Active Compounds with Antibacterial Activity

Abstract

Patchouli (Pogostemon cablin), is a shrub with fragrant-smelling leaves from which patchouli oil is extracted. The oil has properties suitable for aromatherapy, relief of stress and anti-inflammatory activity. Water-steam distillation is the best method for extraction of patchouli oil. Fresh patchouli leaves gave much lower yield than dried leaves. Dried leaves fermented for 77 days at room temperature produced the highest yield (2.48% dry wt), which was much higher than from drying in an oven at 50°C for 40 h (0.30% dry wt). Soxhlet extraction of dried patchouli leaves with hexane for 15 h provided crude hexane extract (4.97% dry wt). The hexane extract was further separated and purified to obtain patchouli alcohol (0.05% dry wt), a mixture of β-sitosterol and stigmasterol (0.09% dry wt) and 7,3′,4-tri-O-methyleriodictyol (0.04% dry wt). Antibacterial activity assay showed that patchouli oil could inhibit Staphylococcus aureus and Bacillus subtilis better than the hexane extract. Patchouli alcohol, a major component in patchouli oil, and the extract showed higher antibacterial activity than the mixture of β-sitosterol and stigmasterol and 7,3′,4-tri-O-methyleriodictyol. Therefore, patchouli alcohol could be used as a marker for quality control of patchouli oils and the extracts. Quantitative determination of patchouli alcohol in the patchoulil oils and the hexane extract was performed by GC-MS using the new optimum conditions. The results showed that patchouli oil contained more patchouli alcohol than the hexane extract. Time of leaf harvesting (3 months, 6 months and 9 months) was also important. Threemonth harvesting of patchouli leaves gave the highest amount of patchouli oil and patchouli alcohol.