Chemical constituents and cytotoxic activity of the root wood of Magnolia kachirachirai

Magnolia kachirachirai (Kanehira Yamamoto) Dandy (Magnoliaceae) is a large endemic evergreen tree growing in the southeastern part of Taiwan. The methanolic extract of the root wood of this species has shown cytotoxicity on high-throughput screening against MCF-7 (breast cancer), NCI-H460 (lung cancer) and SF-268 (central nervous cancer) cancer cell lines and was partitioned into neutral CHCl 3 , tertiary base, n -BuOH, and H 2 O-soluble layers. The neutral CHCl 3 -soluble layer showed cytotoxicity against these cancer cell lines. Investigation of the active CHCl 3 -soluble layer by column chromatography and prep. TLC has led to the isolation of one new compound: kachiraterpenol ( 1 ), along with twenty known compounds: costunolide ( 2 ), α-cyclocostunolide ( 3 ), T-cadinol ( 4 ), dehydrosaussurea lactone ( 5 ), dihydro-β-cyclocostunolide ( 6 ), N -acetylanonaine ( 7 ), N -acetyldehydroanonaine ( 8 ), N -acetylnorstephalagine ( 9 ), glaberide I ( 10 ), a mixture of 6-(3-methoxy-4-hydroxyphenyl)-3,7-dioxabicyclo-[3.3.0]-octan-2-one ( 11 ) and 6-(3-hydroxy-4,5-dimethoxyphenyl)-3,7-dioxabicyclo-[3.3.0]octan-2-one ( 12 ), syringaldehyde ( 13 ), linoleic acid ( 14 ), 1,2-dipalmitoyl-3-oleoylglycerol ( 15 ), a mixture of β-sitosterol ( 16 ) and stigmasterol ( 17 ), a mixture of (24 R )-stigmast-4-en-3-one ( 18 ) and (22 E ,24 S )-stigmast-4,22-dien-3-one ( 19 ), a mixture of (24 R )-6β-hydroxystigmast-4-en-3-one ( 20 ) and (22 E ,24 S )-6β-hydroxystigmast-4,22-dien-3-one ( 21 ). The structures of these isolates were elucidated by spectral analysis. The sesquiterpenoid costunolide ( 2 ) as major component showed cytotoxicity against MCF-7, NCI-H460 and SF-268 (IC 50 : 5.3, 6.9, 5.3µg/mL) cancer cell lines in vitro . Acknowledgements: This work was kindly supported by a grant from the National Science Council of the Republic of China.