Abstract:

Purpose: To investigate the dynamic accumulation pattern of the main antibacterial constituent, polysaccharides
in Kudingcha collected at different months. Methods: Kudingcha was subjected to reflux extraction on a hot water bath
and the process was repeated for three times. The cylinder plate method was used to measure the antimicrobial capacity.
The diameter of inhibition zone was used to determine the optimal harvest time for Kudingcha. The sugar content was
determined by the phenol sulfuric acid method. The correlation between polysaccharides and antibacterial activity was
evaluated. The fingerprint spectra of Kudingcha aqueous extract obtained by Fourier transform infrared spectroscopy
(FTIR) were studied and the correlation between characteristic peaks and antibacterial activity was evaluated. Results: The
polysaccharide content in Kudingcha increased gradually during the first three months, and reached the peak of 96.6 mg/g
in April. Then, it declined gradually to the lowest level of 47.7 mg/g in December. The greatest diameters of inhibition zone
of Escherichia coli, Staphyloccocus aureus Rosenbach, Pseudomonas aeruginosa were observed when exposed to aqueous
extract of Kudingcha harvested in April, and the lowest level when exposed to Kudingcha harvested in December. This trend
was similar to the observation for polysaccharide content. Conclusion: The content of antibacterial components is at the
highest level in Kudingcha harvested in April, and the best harvest period is in April. Glycosides and polysaccharides are
antibacterial components in Kudingcha.

Key words: Ilex kudingcha C. J. Tseng, harvest period, bioactive polysaccharides, Fourier transform infrared spectrometer(FT-IR), antibacterial activity