Abstract

• Tayoke Nan-nan is known to be rich in essential oil and phenolic compounds. GC-MS analysis of the essential oil steam distilled from the dry leaf (yield 0.02 %) of Apium graveolens L. indicates nine compounds, mostly mono and sesquiterpenes, phthalide derivatives, and a few other compounds. Similar analysis of the essential oil from the fresh leaf (yield 0.07 %) showed fourteen compounds, mostly mono and sesquiterpenes, the phthalide derivatives and a few other compounds. Phthalides are the most abundant constituents in both essential oils. In the determination of antioxidant activity by ferric reducing antioxidant power (FRAP) method, EC50 values of the ethanolic extracts of the leaf, stalk and root were 2186, 984 and 2316 μg/mL against 112 μg/mL of ascorbic acid standard. The presence of phthalides and phenolic compounds in the plant, Tayoke nan-nan may be useful as a medicinal drug in certain miner diseases.