Relationship between leaf position and antioxidant properties in three basil species

Variation in antioxidant contents and activities in leaves from the top to the base of holy basil, lemon basil and sweet basil shoots was investigated. The contents of chlorophyll a and chlorophyll b were not different in all leaf positions while those of β-carotene, ascorbic acid, phenolics and flavonoids depended on both the location of leaves and plant species. Holy basil contained a high amount of phenolics in all leaf positions but sweet basil leaves were rich in flavonoids from the top and middle regions of the plants which might be related to the high value of DPPH free radical scavenging activity but not the ferrous iron chelating ability. In contrast, the bottom leaves of lemon basil had the highest DPPH scavenging activity while the middle leaf of this herb had the highest activity of ferrous ion chelation. This ability in lemon basil leaves was also obviously higher than that in the other two basils.