Enrichment of patchouli alcohol in patchouli oil by aiding sonication in hydrotropic extraction

Patchouli alcohol, a tricyclic sesquiterpene, is a vital component of patchouli essential oil which is primarily isolated from the aerial part of Pogostemon cablin and is majorly used in fragrance industries. An intensified technique of hydrotropy coupled with sonication was investigated to enhance the purity of patchouli alcohol in patchouli oil using four different hydrotropes viz., resorcinol, p-toluene sulphonic acid, sodium salicylate, and sodium cumene sulphonate. The influence of various parameters namely sonication time (5 and 15 min), ultrasound amplitude (20-40 %), and pulse ratio (10:50 and 30:30 s) over varying concentration of hydrotropic solution (0.2-2 M) on the patchouli alcohol content was assessed using parametric study. Amongst the four hydrotropes, sodium cumene sulphonate has provided the highest purity (96.12 %) of patchouli alcohol for 0.2 M concentration, 15 min sonication time, 40 % amplitude, and 30:30 s pulse ratio against 33.13 % in pure oil. Hydrotropy combined with ultrasound treatment has enriched the composition of patchouli alcohol in patchouli oil to a larger extent when compared with hydrotropic extraction without sonication. Further, a scale-up study has provided promising outcomes suggesting a suitable alternative technique as a sustainable solution.