Abstract:

‘Hongyou’ Chinese toon (Toona sinensis), the major cultivar in China, was used to investigate the nutritional
components and antioxidant activity of tender buds at three different harvesting periods, with the aim of providing a
theoretical basis for selecting its best harvesting time. The results showed that the contents of chlorophyll, soluble sugar,
soluble protein and flavone in Toona sinensis leaves were higher at phase Ⅲ (which were 1.72, 119.94, 3.87 and 11.83 mg/g,
respectively) than two other phases. The contents of chlorophyll, amino acids, proteins, polyphenols and flavones in leaves
were significantly higher than those in stems of Toona sinensis (P < 0.01) at all harvesting periods, while no significant
difference in soluble sugar at phase Ⅲ and vitamin C at phase Ⅰ between leaves and stems was observed. The antioxidant
activity of Toona sinensis bud extracts at different harvesting times and from different parts indicated a significant doseeffect
relationship (P < 0.05). Toona sinensis bud leaf extracts showed higher scavenging capacity against DPPH free
radical but lower scavenging capacity against hydrolxyl free radical than Toona sinensis bud stem extracts. The scavenging
capacity against hydrolxyl free radical and total reducing power of Toona sinensis bud extracts were the strongest at phase Ⅱ,
while the DPPH radical scavenging capacity were the highest at phase Ⅰ. Considering the variations of nutrient contents,
antioxidant activity and edibility, phase Ⅱ is the best harvesting time for the ‘Hongyou’ cultivar of Toona sinensis.

Key words: Toona sinensis, harvesting time, nutritional components, antioxidant activity