No abstract

The new sesquiterpenoid (6R)-2-chloro-6-[(1S)-1,5-dimethylhex-4-en-1-yl]-3-methylcyclohex-2-en-1-one (1), together with ten known compounds, (6R)-6-[(1S)-1,5-dimethylhex-4-en-1-yl]-3-methylcyclohex-2-en-1-one (2), bauerenol acetate (3), lupenone (4), alpha-amyrenone (5), beta-sitosterol (6), stigmasterol (7), beta-amyrin (8), ursolic acid (9), betulinic acid (10), scopolin (11), have been isolated from the roots of Euphorbia chrysocoma Lévl. et Vant. Their structures have been elucidated by spectroscopic data.

Chemical investigation on the gorgonian Menella kanisa collected from Beibu Gulf led to the isolation of a new diketopiperazine, named menazepine A (1), as well as three known diketopiperazines, namely cyclo(4-hydroxyprolylleucyl) (2), cyclo(Pro-Leu) (3) and cyclo(4-hydroxyprolylphenylalanyl) (4). The structure of the new diketopiperazine was elucidated on the basis of extensive spectroscopic analysis and by comparing the data with those of related metabolites. Compounds 1-4 were also evaluated for brine shrimp lethality.

Two new diterpenoids, anthogonoid A and antsimplexin A (1-2), as well as a known diterpenoid, klysimplexin G (3), were isolated from a Beibu Gulf gorgonian coral, Anthogorgia caerulea. The structures of these compounds have been established by detailed spectroscopic analysis and by comparison with spectral data of related known compounds. Compounds 1-3 showed significant antifouling activity against the larval settlement of Balanus amphitrite.