In recent years

natural antioxidants that were used to substitute synthesized antioxidants become trends of international and domestic researches. Aromatic plants have been widely paid attention due to their (ability) of antioxidation. In the present study the nonvolatile parts of dry leaves from large sweet basil and (meyer) lemon (below called basil and lemon) were taken as experiment material. Six chemilum inescence systems and two colorimetric systems were used to evaluate their capacity of antioxidation and that of preventing DNA damage caused by

·

OH. The experiments revealed that basil and lemon could not only directly scavenge O

(·)

2

but also inhibit the bioactivity of xanthine oxidase and then reduce the production of O

(·)

2

. Experiments (also) showed that basil and lemon could efficiently scavenge

·

OH

H

2

O

2

ONOO

·

and DPPH

·

.Moreover

lemon has a better ability to scavenge H

2

O

2

ONOO

·

and DPPH

·

than that of basil. Basil and lemon could effectively inhibit lipid peroxidation and they could obviously inhibit and delay DNA damage caused by

·

OH

acting as mixing-type antioxidants. Above results indicate that basil and lemon are very effective antioxidants and free-radical scavengers. Meanwhile famous antioxidant baicalin is taken as a comparison. Baicalin is better in the capacity of antioxidation than basil and lemon in most of the system

but baicalin was purer and the (extraction) process is more complex and needs more cost than basil and lemon. So it is very significant to research on the exploitation and application of basil and lemon. These experiments provide new data for their further exploitation and establish theoretic base for the function study of basil and lemon on food

hygiene and medicine.