Three Novel Compounds from the Flowers of Bombax malabaricum

Two unusual 9′‐norneolignans, bombasin ( 1 ) and bombasin 4‐O‐β‐glucoside ( 2 ), and a novel D ‐gulono‐γ‐lactone derivative, bombalin ( 3 ), were isolated from the flowers of Bombax malabaricum, together with the three known compounds dihydrodehydrodiconiferyl alcohol 4‐O‐β‐D ‐glucopyranoside ( 4 ), trans‐3‐(p‐coumaroyl)quinic acid ( 5 ), and neochlorogenic acid ( 6 ). Their structures were elucidated by extensive spectroscopic methods as well as chemical transformation. Compounds 1 – 3 were evaluated against the HGC‐27 gastrointestinal and Hela cervical human cancer cell lines, but all were inactive in both lines (IC₅₀>50 μM ).     

Catunaregin and Epicatunaregin,Two Norneolignans Possessing an Unprecedented Skeleton from Catunaregam spinosa

Catunaregin ( 1 ) and epicatunaregin ( 2 ), two novel norneolignans with a unique O‐bridged furopyran ring, together with three known neolignans, ficusal, balanophonin, and 5″‐methoxy‐4″‐O‐(8‐guaiacylglycerol)buddlenol A, were isolated from the stem bark of Catunaregam spinosa, a Chinese mangrove associate. Their structures were elucidated by spectroscopic means, including two‐dimensional NMR techniques. Compounds 1 and 2 exhibited moderate inhibition against the mammary cancer F10 cell line.