Abstract:

The antioxidant activities in vitro of n-butanol extract from Liquidambar formosana leaves prepared by sequential
extraction with ethanol and n-butanol, and macroporous resin chromatography as the 50% ethanol eluate were examined by
1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl (·OH), superoxide anion (O2 - ·) and reducing power assays. The effects of
different concentrations of the extract（0, 10, 30, and 50 mg/100 mL）on storage characteristics of post-harvest kumquats
were investigated. After pre-impregnation with the extract at 10, 30, or 50 mg/100 mL, kumquats were stored at room
temperature (14–16 ℃). During storage, mass loss rate, decay rate, hardness, total soluble solids (TSS), titratable acid (TA),
malondialdehyde (MDA), superoxide dismutase (SOD), and vitamin C (VC) were measured at 3-day intervals. The results
showed that the extract from L. formosana leaves possessed strong reducing power and scavenging activities against DPPH,
hydroxyl, and superoxide anion free radicals, and could reduce decay rate, mass loss and MDA content, retard the decrease
in hardness and TSS, TA, VC content and enhance the activity of SOD. These results indicated that the n-butanol extract
from L. formosana leaves has promising applications in postharvest preservation of kumquat fruits.

Key words: Liquidambar formosana leaves, n-butanol extract, antioxidant activity, Fortunella margarita, storage, physiological properties