Technical Abstract: Chemical investigation of the endophytic fungus 39140-2, isolated from the medicinal plant Hintonia latiflora, yielded the known polyketide vermelhotin (1) and a new salycilic aldehyde derivative, namely 9S,11R-(+)-ascosalitoxin (2). The structure and absolute configuration of the new compound was established through extensive NMR spectroscopy and molecular modeling calculations at the DFT B3LYP/DGDZVP level which included the comparison between theoretical and experimental optical rotation. In addition, chemical transformations of 2 yielded suitable derivatives for NOESY and 1H-1H NMR coupling constants analyses which reinforce the stereochemical assignment. The potential affinity of 1 and 2 with (Ca+2)4-hCaM in solution was also measured using the fluorescent biosensor hCaM M124C-mBBr. The results showed that only 1 bound to the protein with a dissociation constant (Kd) of 0.25 ± 0.04 uM, close to that of chlorpromazine (CPZ, Kd=0.64 ± 0.03 uM) a classical CaM inhibitor. The stoichiometry ratio for 1: CaM was 1 to 4 as for other well-known CaM-ligands.