Extraction and Antitumor Activity of Pedunculagin from Eucalyptus Leaves

As a part of trials to develop the antitumor agent from tannins, the antitumor activity of pedunculagin, an ellagitannin, isolated from eucalyptus leaves, was reported in this paper. In vitro, the antitumor activity was determined by MTT assay. Pedunculagin showed the dose-dependent antitumor activity against human liver tumor cells (QGY-7703), the 50% inhibition concentration (IC50) was (64.3±6.1)μg/mL, Under microscope, holes-like structure was observed on the membrane of tumor cells, which co-cultured with pedunculagin, but it was negative for human normal cell (HEB), this means pedunculagin can change the structure of tumor cell membrane specifically, when 5-Fu was mixed with 5μg/mL of pedunculagin, the IC₅₀ of 5-Fu greatly reduced to (0.9±0.6) μg/mL from (5.9±2.2) μg/mL, the probably reason is that pedunculagin can improve the permeability of tumor cell membrane. This paper first reports the phenomena of holes-like structure on the membrane of tumor cells caused by pedunculagin.