Full Length Research Paper

Promotive effect of 5-aminolevulinic acid on the antioxidant system in Ginkgo biloba leaves

Feng Xu^1*, Jie Chang¹, Shui Yuan Cheng^2*, Jun Zhu³, Lin Ling Li², Yan Wang¹ and Hua Cheng¹

¹College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, China.

²College of Life Science and Engineering, Huanggang Normal University, Huangang 438000, China.

³Department of Bio-medicine, Zhongshan Torch Polytechnic, Zhongshan 528436, China.

*Corresponding author. E-mail: xufeng@yangtzeu.edu.cn or s_y_cheng@sina.com Tel: +86-716-8066260. Fax: +86-716-8066262.

Accepted 5 June, 2009

The effect of 5-aminolevulinic acid (ALA), a key precursor in the biosynthesis of porphyrins, at low levels (10 and 100 mg l-1) on the antioxidant system in Ginkgo biloba leaves were investigated. The results showed that ALA-treatment accelerated hydrogen peroxide accumulation and temporarily increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) at day 4 and 8. The activities of glutathione reductase (GR) and dehydroascorbate reductase (DHAR) and the contents of ascorbic acid (AsA) and glutathione (GSH) were all significantly increased by ALA, while dehydroascorbate (DHA) content was decreased and no variety was observed in oxidized glutathione (GSSG) content after ALA treatment. The ALA-treated leaves had higher values of AsA/DHA and GSH/GSSG than those in the control leaves. These results suggested that foliar treatment with a low concentration of ALA might provide a useful means of improving beneficial antioxidant activity in G. biloba leaves.

Key words: Antioxidant system, flavonoids, 5-aminolevulinic acid, Ginkgo biloba.