Root bark preparation ofAnnona senegalensisPers. (Annonaceae) is used in Nigerian ethnomedicine for treatment of infectious diseases. Extraction of theA. senegalensispowdered root bark with methanol-methylene chloride (1 : 1) mixture yielded the methanol-methylene extract (MME) which was fractionated to obtain the ethyl acetate fraction (EF). The EF on further fractionation gave two active subfractions, F1 and F2. The F1 yielded a lipophilic oily liquid while F2 on purification, precipitated white crystalline compound, AS2. F1 was analyzed using GC-MS, while AS2 was characterized by proton NMR and X-ray crystallography. Antibacterial and antifungal studies were performed using agar-well-diffusion method with 0.5 McFarland standard and MICs calculated. GC-MS gave 6 major constituents: kaur-16-en-19-oic acid; 1-dodecanol; 1-naphthalenemethanol; 6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-ethanol; 3,3-dimethyl-2-(3-methylbuta-1,3-dienyl)cyclohexane-1-methanol; 3-hydroxyandrostan-17-carboxylic acid. AS2 was found to be kaur-16-en-19-oic acid. The MICs of EF, F1, and AS2 againstB. subtiliswere 180, 60, and 30 μg/mL, respectively. AS2 exhibited activity againstS. aureuswith an MIC of 150 μg/mL, while F1 was active againstP. aeruginosawith an MIC of 40 μg/mL. However, the extracts and AS2 exhibited no effects againstCandida albicansandAspergillus niger. Therefore, kaurenoic acid and the lipophilic fraction fromA. senegalensisroot bark exhibited potent antibacterial activity.
Kaurenoic Acid Isolated from the Root Bark of Annona senegalensis Induces Cytotoxic and Antiproliferative Effects against PANC-1 and HeLa cells
