Four novel compounds, conarubins A–D (1–4), were isolated from the whole plants of Conamomum
rubidum collected in Vietnam. Their structures were elucidated
by extensive spectroscopic analyses and by quantum chemical calculations
of NMR and ECD. Compounds 1 and 2 were the
first examples of monoterpene–monoterpene–chalcone conjugates
in nature, whereas compound 4 was an unprecedented monoterpene-substituted
chalcone containing a 3,4,5-trioxygenated cyclohexa-2,5-diene-1-one
ring. The anti-inflammatory and cytotoxic activities of all isolates
were investigated.