Angolensin Isolated from Pterocarpus indicus Willd. Attenuates LPS-Induced Sickness Behaviors in Mice and Exhibits CNS Safety

Folk medicine in Thailand has long made use of Pterocarpus indicus Willd. for treating inflammation-related disorders. However, scientific exploration of isolated compounds from P. indicus for improving inflammation-associated sickness conditions and their impact on central nervous system (CNS) safety remain unexplored. The present study initially screened the anti-neuroinflammatory effects of angolensin, a compound isolated from P. indicus heartwood in vitro. Following substantial findings, the efficacy of angolensin was further evaluated in a mouse model of lipopolysaccharide (LPS)-induced sickness behaviors, alongside an assessment of its CNS safety profiles. The anti-neuroinflammatory effects of angolensin were evaluated in LPS-induced BV-2 microglial cells. The effects of angolensin on sickness behaviors were examined in LPS-induced mice using the Laboratory Animal Behaviors Observation, Registration and Analysis System (LABORAS). Proinflammatory cytokine expression in plasma samples of mice was also determined. LABORAS and rotarod tests were conducted to investigate its impact on the CNS. In vitro assessment of the anti-inflammatory activity of angolensin on BV-2 microglial cells revealed a concentration-dependent reduction in the release of LPS-induced nitric oxide (NO) and proinflammatory cytokines (TNF-α and IL-6). At a concentration of 20 µM, angolensin showed comparable results to the positive control, 20 µM minocycline. In mice, angolensin significantly improved LPS-induced sickness behaviors, as indicated by improved home-cage behaviors. Consistent with the in vitro findings, angolensin attenuated the release of proinflammatory cytokines in the plasma of LPS-induced mice. Importantly, angolensin did not induce any adverse effects on locomotion, motor coordination, or general well-being, indicating a favorable CNS safety profile. Overall, these results highlight the anti-inflammatory potential of angolensin in mitigating sickness behaviors in mice, while demonstrating its CNS safety.