Fractionation Of Larch Bark Proanthocyanidins And The Research On Fine Application Of The Fractions

Larch bark, the byproduct of forestry industry consisting about 16% proanthocyanidins (PCs), is an abundant reproducible plant biomass resource. As for its comprehensive chemical and biologic activities, PCs could be widely used in foods, health products, medicines, cosmetics, et al. In this thesis, the PCs in larch bark was extracted and fractionated by ingeniously utilizing the principles of tannin chemistry, natural products chemistry and fine chemical engineering. Meanwhile, a fraction that has high polymeric degree was catalytically hydrogenolysed by Pd/C. The chemical characteristics and biological activity of all the fractions or products were extensively investigated.In the first part of this thesis, a math model for extracting PCs was built by using the experimental method of quadr-general- turning-assembly design. With the help of digital processing system and the frequency analyses, the extraction condition was optimized, that is, the raw material of 8.5~11.6g was extracted by 250mL 57~64% ethanol solution at 60～70℃for 4 times ( 95~107 min for each time). The yields of total extracts and PCs predicted by the math model were 23.83% and 16.27%, which were nearly equal to values actually measured. The extraction rates of total extracts and PCs were as high as 92.27% and 93.39%. Therefore, this research could provide approach for optimizing parameters and predicting the...