Two New Cassane Diterpenoids From the Aerial Parts of Caesalpinia pulcherrima

Two new cassane diterpenoids featuring an α,β-unsaturated γ-lactone fused to ring C, pulcherrilactones A and B (1 and 2), along with two known compounds, neocaesalpins F and G (3 and 4), were isolated from Caesalpinia pulcherrima. The chemical structures of these cassanoids were elucidated using spectroscopic and spectrometric techniques, including infrared, ultraviolet, nuclear magnetic resonance, and high-resolution mass spectrometry. The α-glucosidase inhibitory activity of all isolated compounds was evaluated. Among them, compound 2 exhibited the most potent activity, with a 50% inhibitory concentration value of 171 ± 5.56 µM.