Seasonal variation of volatile oil composition and antioxidant property of aerial parts of Syzygium paniculatum Gaertn. grown in the Eastern Cape, South Africa

Syzygium paniculatum Gaertn of the family Myrtaceae is a medicinal and aromatic plant. The hydrodistilled volatile oil (VO) from the aerial parts was characterised by GC-MS and Kovat’s index, while the antioxidant property was investigated using spectrophotometric techniques. Antioxidant capacities of the aerial parts VOs range from 0.12 to 0.93 mg/mL in scavenging 2, 2-diphenyl-1-picrylhydrazyl radicals (DPPH^•). Overall, 75 and 67 compounds were identified from the summer and winter VOs, respectively. The main compounds were α-pinene (33.13%), n-hexadecanoic acid (19.14%), limonene (14.26%), farnesol (14.21%), β-ocimene (13.04%), citronellol (12.67%), linoleic acid (11.50%), octahydro-1,4-dimethyl azulene (11.57%), citral (9.91%), phytol (5.07%), linolenic acid (4.85%) and thymol (2.23%). The bioavailability of citronellol, thymol, β-ocimene and linoleic acid, used as bactericidal, fungicidal and antioxidant agents in cosmetics and perfumery, suggests S. paniculatum potential as a natural food flavouring and source of antibiotics in this era of emerging multi-drug-resistant pathogens.