New diterpenes from Nigella damascena seeds and their antiviral activities against herpes simplex virus type-1.

Nigella species are rich source of dolabellane diterpenes. During our study of Nigella species, new dolabellane diterpenes, damasterpenes V-VIII were isolated. The structural determination of new compounds damasterpenes V-VIII is described with consideration of their absolute configurations. The antiviral activities against herpes simplex virus type-1 of the isolated compounds and their derivatives are also evaluated. Damasterpene V (inhibition 35.0%) and 2-phenylacetyl 13-benzoyl damasterpenol (32.0%) showed significant antiviral activity at 10 μM.