Isolation of Phenolic Compounds from the Stem Bark of Anisoptera laevis (Dipterocarpaceae)

Anisoptera is a minor genus of Dipterocarpaceae, with 10 species that are extensively spread in Malaysia and Indonesia. The members of this genus contain rich sources of oligostibenoids such as dimer and tetramer stilbenoids which were identified to have potential antiviral and antioxidant activities. Nevertheless, only four species of this genus have isolation reports. Herein, A. laevis was selected to be phytochemically investigated in order to develop a chemical profile of this species. The powder from the stem bark of A. laevis (900 g) was macerated in acetone at room temperature for 24 hours and repeated three times. The crude acetone extract (65 g) obtained was fractionated by vacuum liquid chromatography (VLC) with the eluent n-hexane-ethyl acetate in increasing polarity resulting in eight semi-purified fractions (AL1-8). Fraction AL2 (620 mg) was purified by column chromatography (CC) with the solvent system of n- hexane-ethyl acetate to afford a pure compound 1 (8.9 mg). Compound 2 (8.5 mg) was isolated from fraction AL3 (940 mg) using CC (chloroform:methanol). The purification of fraction AL4 (1 g) using CC (chloroform: methanol) yielded compound 3 (205 mg). Based on Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) and comparison with literature data, the isolates were determined as pentadecyl ferulate (1), p-hydroxybenzaldehyde (2), and vaticanol B

(3) ([Fig. 1]).

Fig. 1  Structure of compounds 1-3.

Funding We would like to express our greatest appreciation to Universiti Teknologi MARA, Malaysia for the financial support [600-RMC/SRC/5/3(025/2020)].