Reduction of curcuminoid extract from turmeric (Curcuma longa) rhizomes and its antibacterial activities

Abstract

Curcuminoid is an active compound of turmeric rhizomes commonly used as yellow pigment. In some cases, the presence of pigment in beauty product is not desirable due to its aesthetics effect. In this study, yellow color removal of curcuminoid was carried out by two steps hydrogenation, i.e. using LiAlH4 followed by Pd-C catalyst to form dihydrocurcuminol and hexahydrocurcuminol derivatives, respectively. Dihydrocurcuminol derivatives had successfully synthesized by observing a wavelength shift from 419 to 428 nm in UV-Vis spectra and FTIR spectra also showed a reduction intensity of the carbonyl groups at 1600 cm-1. Moreover, hexahydrocurcuminol derivatives were identified at 283 nm in UV-Vis spectra while in FTIR spectra showed an absorption band of C-H sp3 at 2942 cm-1. Curcuminoid and hexahydrocurcuminol derivatives were evaluated for their antibacterial activities against Staphyloccocus aureus with 2 and 2.5 mm and Fusobacterium nucleatum with 4 and 2.75 mm inhibitory zone diameter, respectively. It can be concluded that curcuminoid and hexahydrocurcuminol derivatives had a weak antibacterial activity against both bacteria tests.