Abstract: The bamboo Neosinocalamus affinis is distributed widely in China.Its leaves contain natural antioxidants with no toxicity.To optimize the extraction conditions of antioxidants from the leaves of N.affinis, a series of single factor experiments were carried out to evaluate the effects of ethanol concentration,particle size,extraction methods,extraction duration,ratio of solid to liquid,extraction temperature,and times of extraction on yields of antioxidants.An orthogonal test L₉ (3⁴) was then applied to further optimize extraction conditions based on the results of single factor experiments.The optimal extraction conditions were thus established as:2028 mesh of N.affinis leaves was extracted with 10 times (v/m) 60% EtOH under 70 ℃ for 1.5 h,to obtain 7.44 mg antioxidants from 1 g of N.affinis leaves,which was proved to be stable and feasible by the verification experiment.Quantitative analysis demonstrated that 1 g of dry N.affinis leaves contained 4.73 mg of total phenols and 5.52 mg of total flavonoids.

Key words: Neosinocalamus affinis, VCEAC, antioxidant, total phenols, total flavonoids