A Conformational Isomer of Soulattrolide from the Stem Bark of Calophyllum symingtonianum and Its Antibacterial Activity

Callophylum symingtonianum (Guttiferae), an evergreen broad-leaved tree that usually grows in hill forests, can be found distributed in the Malay Peninsula. The barks, leaves, flowers and seeds is often used medicinally to treat diarrhea and rheumatism. In the present study, we isolated two inophyllum type coumarins, 12-O-ethylinophyllum D (1) and iso-soulattrolide (2) from the stembarks of C. symingtonianum together with their antibacterial activity. The compounds were isolated by chromatographic methods on a silica gel. The structures were established by spectroscopic methods including UV, IR, (1D and 2D) NMR and mass spectrometry as well as by comparison with several literature sources. The antibacterial activity of those compounds was tested using a disc-diffusion assay against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Both compound exhibited mild inhibition against P. aeruginosa with both 111 µg/ml MIC value. Compound 2 also inhibits S. aureus with 25 µg/ml MIC value.

Cytotoxic and Antibacterial Evaluation of Coumarins and Chromanone Acid from Calophyllum symingtonianum.

Calophyllum symingtonianum is a rare species from the Calophyllum genus that belongs to the Guttiferae family. Calophyllum has been recognized as a potential medicinal plant due to its many bioactive phytochemicals especially coumarins and chromanone acids. In this study, the cytotoxic activities against MCF-7 and A-549 and antibacterial activities towards S. aureus, B. subtilis, P. aeruginosa and E. Coli of three coumarins known as inophyllum D, inophyllum H and calanone as well as chromanone acid identified as isocordato-oblongic acid isolated from this plant were evaluated. Inophyllum H exhibited the highest IC50 values against MCF-7 at 25.56 μg/mL and A-549 at 26.41μg/mL. Isocordato-oblongic acid showed moderate antibacterial activity against S. aureus and B. subtilis at 125μg/mL and 62.5μg/mL, respectively. This study suggests C. symingtonianum as a potential plant for cytotoxic and antibacterial phytochemicals.