Pili Tree (Canarium ovatum) Resin's Antibacterial Essential Oil and Hydrosol as Rich Sources of ( S )‐Phellandrenes Derivatives

Five batches of resin from the Pili tree ( Canarium ovatum Engl.) were distilled, and their essential oils and hydrosols were analyzed by gas chromatography. The oils, obtained in yields of 13.4–19.7 % v/m, featured α‐phellandrene in high proportions (50–65 %), alongside limonene, β‐phellandrene and para ‐cymene. Chiral GC analysis confirmed that both phellandrenes were in fact >95 % ( S )‐(+) enantiomers, while the other monoterpenes featured less pronounced enantiomeric excesses. The hydrosols were rich in α‐phellandrene oxidation products including cis‐ α‐phellandrene epoxide and a series of para ‐menth‐5‐ene‐1,2‐diol isomers. Both essential oils and hydrosols were tested for their antibacterial activity against Escherichia coli and Staphylococcus aureus and exhibited MIC 90 of less than 5 and 0.5 mg/mL of total volatiles, respectively. The essential oil features some potential as a source of readily available natural ( S )‐(+)‐α‐phellandrene.