Four New Clerodane Diterpenes from the Leaves ofCasearia guianensisWhich Inhibit the Interaction of Leukocyte Function Antigen 1 with Intercellular Adhesion Molecule 1

Four new clerodane diterpenes, casearinols A and B (1 and 2) and casearinones A and B (3 and 4), were isolated from the leaves of Casearia guianensis. These immunomodulatory compounds have been structurally elucidated primarily on the basis of 2D NMR analysis and spectral data comparison with known compounds. These compounds inhibited the binding of T-cell leukocyte function antigen 1 to intercellular adhesion molecule 1.