Abstract:

The aim of this research is to extract, purify and modify nobiletin from dried orange peel. The extraction process
was carried out by means of infiltration. The extract was further extracted with chloroform to obtain a fraction rich in
polymethoxylated flavonoids and the target compounds were separated on a silica gel column with a mobile phase consisting
of a mixture of ethyl acetate and petroleum ether. Pure nobiletin was obtained as indicated by reversed phase HPLC and GC-MS
and through comparison with reference standards. The conversion conditions from nobiletin to 5-demethylnobiletin was optimized
and it was found that 5-demethylnobiletin with a purity higher than 97% was produced when the reaction was performed for 24 h
under heat refluxing condition with a volume ratio of 1:9 between concentrated hydrochloric acid and absolute ethanol

Key words: citrus peel, separation and purification, polymethoxylated flavonoids, nobiletin, 5-demethynobiletin