Hedscandines A-C, three undescribed indole alkaloids from Hedyotis scandens with their anti-MRSA activity

Abstract

Hedscandines A-C (1-3), three undescribed indole alkaloids were isolated from Hedyotis scandens Roxb, a traditional Chinese medicine widely used in the treatment of respiratory ailments. Their structures were elucidated by extensive spectroscopic data and electronic circular dichroism calculation. Hedscandine A (1), possessed a unique carbon skeleton with a 1,4-oxazonin-2(3H)-one core system and displayed a rapid bactericidal activity against MRSA with a MIC value of 16 μg/mL. Mechanistic studies showed that compound 1 could disrupt the integrity of bacterial cell membranes and thus lead to bacterial death.

Keywords: Antibacterial activity; Disrupting bacterial membranes; Hedyotis scandens roxb.; Indole alkaloids; Methicillin-resistant Staphylococcus aureus; Rubiaceae.