Five new cantharidin derivatives from the insect Mylabris cichorii and their potential for the treatment of neuroinflammatory diseases

Abstract

Five previously undescribed monoterpenoids, including two 1,2-dimethyl cantharimide-type derivatives (1 and 2), one 1-hydroxymethyl-2-methyl cantharimide-type derivative (3), and two 1-methyl cantharimide-type derivatives (4 and 5), were isolated from the whole bodies of Mylabris cichorii L. Their structures, including absolute configurations, were identified using 1D and 2D NMR, HRESIMS, and electronic circular dichroism (ECD) calculations. Considering the role of cantharidin derivatives in anti-neuroinflammation, all the compounds were evaluated for their neuroinflammatory activities. Results showed that compound 2 ameliorated LPS-induced neuroinflammation and reduced oxidative stress by targeting mitochondria, thereby decreasing reactive oxygen species (ROS) and pro-inflammatory cytokines. This suggests that compound 2 may be useful in treating neuroinflammatory diseases.