Chemical profiling of Curcuma aeruginosa Roxb. rhizome using different techniques of solvent extraction

Abstract

Objective: To investigate the possible phytochemical constituents of Curcuma aeruginosa Roxb. (C. aeruginosa) rhizome using two different techniques of direct solvent extraction. Methods: Two different techniques of direct solvent extractions, i.e. methyl tert-butyl ether (MTBE) extraction and two-phase methanol/chloroform (M/C) system, were used in this study. The analysis of the phytochemical constituents in MTBE and M/C extracts was performed using gas chromatography-mass spectrometry/mass spectrometry. The mass spectra of the compounds was matched with the NIST 08 mass spectral library. Results: The present study revealed that the extraction using two-phase M/C have resulted in higher metabolite coverage compared to the extraction with MTBE. Direct solvent extraction using MTBE revealed the presence of 27 compounds; whereas, M/C allowed the extraction of 18 and 36 compounds in polar (methanol) and nonpolar (chloroform) fractions respectively. The major compounds detected in the MTBE extract that based on the peak area percentage were methenolone (16.64%), cycloisolongifolene, 8,9-dehydro-9-formyl- (15.93%), labd-13-en-15-oic acid,8,12-epoxy-12-hydroxy-γ-lactone (10.77%), propiolic acid, 3-(1-hydroxy)-2 isopropyl-1,5-methylcyclohexyl) (7.84%), 4-oxo-β-isodamascol (5.17%), velleral (3.11%) and Z-α-farnesene (2.00%). The most prevailing major compounds identified in the polar fraction of the M/C extraction were α-D glucopyranoside, 1,3,4,6 tetrakis-O-(TMS) (trimethylsilyl)-β-D-fructofuranosyl 2,3,4,6-tetrakis-O-(TMS)- (38.08%), d-glucose, 2,3,4,5,6-pentakis-O-(TMS)-, O-methyloxime (14.61%), D-fructose, 1,3,4,5,6-pentakis-O-(TMS)-, O-methyloxime (5.28%), isocitric acid (TMS) (3.06%), oxalic acid, bis (TMS) ester (2.96%), hexadecanoic acid, TMS ester (2.16%), citric acid, ethyl ester, tri-TMS (1.91%) and butanedioic acid, [(TMS) oxy]-, bis (TMS) ester (1.14%); whereas in the nonpolar extract, among the major compounds detected were cycloisolongifolene, 8, 9-dehydro −9-formyl (15.70%), propiolic acid, 3-(1-hydroxy-2-isopropyl-5-methylcyclohexyl) (11.09%), stearic acid, TMS ester (2.78%), hexadecanoic acid, TMS ester (2.33%), oleic acid, TMS ester (1.62%), curzerene (1.56%); Z-α-farnesene (1.52%), germacrone (1.41%) and β-elemene (1.33%). Conclusions: It was evident from the results that C. aeruginosa rhizome extracted using two different techniques of solvent extractions (MTBE and M/C) contained various chemical classes of compounds including terpenoids, sterols, organic acids, fatty acids and sugars. Different methods of extraction have led to different compounds extraction for C. aeruginosa rhizome. The results also indicated that the plant was a source of phytochemical importance.

Keywords

• Curcuma aeruginosa
• Rhizome
• GC-MS
• Profiling
• Phytochemicals