Antimicrobial compounds from Eremophila serrulata

An ο-naphthoquinone, 9-methyl-3-(4-methyl-3-pentenyl)-2,3-dihydronaphtho[1,8-bc]pyran-7,8-dione (2), and a serrulatane diterpenoid, 20-acetoxy-8-hydroxyserrulat-14-en-19-oic acid (3) along with two known serrulatane-type diterpenoids were isolated from the leaves of Eremophila serrulata. All compounds possessed antimicrobial activity against Gram-positive bacteria with MICs ranging from 7.8 to 250 μg/mL.