Abstract: The purpose of this study was to determine the protein,alkaloids content in the roots and aerial parts of Maca cultivated in Lijiang,Yunnan.Constituents and content of protein in both parts was analyzed by hydrolyzing in HCl and pre-column derivatization using OPA and FMOC as auxiliary reagents.Both parts weresuccessively extracted by ethanol and chloroform.Thealkaloids content and radical scavenging capacity of the extract was studied.The amino acid composition of both parts was similar.Total amino acid content in roots (15.10%) was higher than that of aerial parts(14.29%).However,Scores of Thr,Ile,Lys,Leuin FAO/WHO and Egg system showed that nutritive value of aerial parts was significant higher than that roots(P<0.01).The chloroform extract of both roots and acrial parts showed radicals (DPPH·and·OH) scavenging capacity,and had no significant correlation with content of alkaloids.The content of alkaloids in roots and aerial parts was 7.39 mg/gand 3.65 mg/g,the radicals scavenging capacity of both parts were much lower than that of green tea.This work will be a base for development of antioxidative functional food for acrial parts of Macaas well as for the further investigation on the mechanism of biological efficacy of Maca.

Key words: Maca, aerial parts, nutritional evaluation, alkaloids, antioxidant activity