Bicyclo[3.2.1]octane and 6-oxabicyclo[3.2.2]nonane type neolignans from Magnolia denudata.
From the ethyl acetate soluble fraction of twigs of Magnolia denudata (Magnoliaceae), seven new neolignan derivatives, 1-7, were isolated along with eighteen known lignan and neolignan derivatives, 8-25. The structures of the new neolignans were elucidated by means of spectral methods, especially by 1H-NMR and 13C-NMR spectra, and two dimensional NMR methods such as 1H-detected heteronuculear multiple bond connectivity1 (HMBC), 1H-detected multiple quantum coherence (HMQC) and 1H-1H-correlation spectroscopy (COSY). Compounds 1-4 have novel structures possessing a 6-oxabicyclo[3.2.2]nonane skeleton and compounds 5-8 also have novel structures possessing a bicyclo[3.2.1]octane skeleton. The anti-platelet-activating factor (PAF) activity of these compounds was tested by measurement of inhibition activity against acetyl transferase to lyso-PAF.
Kuroyanagi
M
M
School of Bioresources, Hiroshima Prefectural University, Shobara-shi, Japan. kuroyang@bio.hiroshima-pu.ac.jp
Yoshida
K
K
Yamamoto
A
A
Miwa
M
M
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry / Q000302:isolation & purification*; D017705:Lignans / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010944:Plants / Q000737:chemistry*
D019086:Bridged Bicyclo Compounds, Heterocyclic; D017705:Lignans