title: Role of modifier in microwave assisted extraction of oleanolic acid from Gymnema sylvestre: application of green extraction technology for botanicals.
abstract: This work highlights the development of a green extraction technology for botanicals with the use of microwave energy. Taking into consideration the extensive time involved in conventional extraction methods, coupled with usage of large volumes of organic solvent and energy resources, an ecofriendly green method that can overcome the above problems has been developed. The work compares the effect of sample pretreatment with untreated sample for improved yield of oleanolic acid from Gymnema sylvestre leaves. The pretreated sample with water produced 0.71% w/w oleanolic acid in one extraction cycle with 500 W microwave power, 25 mL methanol and only an 8 min extraction time. On the other hand, a conventional heat reflux extraction for 6 hours could produce only 0.62% w/w oleanolic acid. The detailed mechanism of extraction has been studied through scanning electron micrographs. The environmental impact of the proposed green method has also been evaluated.
authors.affiliation: Division of Pharmacognosy, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Vivekananda
authors.initials: V
authors.lastname: Mandal
authors.forename: Saikat
authors.initials: S
authors.lastname: Dewanjee
authors.forename: Subhash C
authors.initials: SC
authors.lastname: Mandal
mesh_terms: D031104:Gymnema sylvestre / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D000432:Methanol; D008855:Microscopy, Electron, Scanning; D008872:Microwaves; D009828:Oleanolic Acid / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry* / Q000648:ultrastructure; D010946:Plants, Medicinal / Q000737:chemistry
chemical_list: D010936:Plant Extracts; D009828:Oleanolic Acid; D000432:Methanol