Chemical Composition and Antioxidant Activities of the Essential Oils of Five Magnoliaceae Species from South China

The essential oils of five Magnoliaceae plants, namely Manglietia moto Dandy, Manglietia yuyanensis Law, Michelia chapensis Dandy, Michelia foveolata Merr. ex Dandy, and Michelia, maudiae Dunn, growing wild in Nanling National Nature Reserve of Guangdong province, were analyzed for their chemical composition and tested for their antioxidant effectiveness. The GC-MS analyses as well as comparison of the retention indices (RI) of elution peaks with literature data were used in compound identification of the essential oils; the β-carotene bleaching (BCB) test method was used in the preliminary evaluation of antioxidant activities for them. The M. maudiae oil characterizes high contents of monoterpenes, while other four oils are all constituted mainly by sesquiterpenoids. The high consistence of composition and similarities in major constituents between the M. mow and M. yuyanensis oils may indicate their close cone1ation between relatives. The 50% inhibition were accomplished with 6.6 g/L of M. moto oil, 9.8 g/L of M. yuyanensis oil, 11.3 g/L of M. foveolata oil and 12.2 g/L of M. chapensis oil, respectively, whereas M. maudiae oil could not inhibit 50% of the bleaching reaction under the test conditions.