Abstract:

The pigments from Loropetalum chinense var. rubrum flower were obtained by 20% ethanol extraction followed by microwave treatment. After the multi-stage extraction with n-butanol-petroleum ether, ethyl ether and ethyl acetate, the pigments were subjected to separation by silica-G thin-layer chromatography (TLC). We analyzed detailly the spectral properties of two main fractions obtained from the pigments. The thin-layer plate containing 1.8% sodium carboxymethyl cellulose (CMC) was found to be the most effective TLC plate for separation of the pigments. The maximum separation efficiency was achieved when the developer was composed of distilled water, ethanol, n-butanol and ethyl acetate at the ratio of 11:8:30:36. Seven water-soluble components were isolated from the crude pigments (two of them as the main contributor of the pigment color). The pigments from Loropetalum chinense var. rubrum flower contained anthocyanidin. In the case of the two main color contributors of the pigments, monomer Ⅰ may be isoflavones and monomer Ⅱ may be either isoflavones or anthocyanidin.

Key words: Loropetalum chinense var. rubrum, flower, pigment, thin-layer chromatography (TLC), separation, spectral properties