Modified ent -Abietane Diterpenoids from the Leaves of Suregada zanzibariensis .

The leaf extract of gave two new modified -abietane diterpenoids, zanzibariolides A () and B (), and two known triterpenoids, simiarenol () and β-amyrin (). The structures of the isolated compounds were elucidated based on NMR and MS data analysis. Single-crystal X-ray diffraction was used to establish the absolute configurations of compounds and . The crude leaf extract inhibited the infectivity of herpes simplex virus 2 (HSV-2, IC 11.5 μg/mL) and showed toxicity on African green monkey kidney (GMK AH1) cells at CC 52 μg/mL. The isolated compounds - showed no anti-HSV-2 activity and exhibited insignificant toxicity against GMK AH1 cells at ≥100 μM.