Screening for Anticancer Activity of Leaf Ethanolic Extract of Alpinia elegans ("tagbak") on Human Cancer Cell Lines

Lung, liver, and colorectal cancers are among the leading causes of cancer-related deaths in the Philippines. As chemotherapeutic treatments remain expensive, native plants are being studied as alternative treatments for use in primary care. In this study, Alpinia elegans leaf ethanolic extract ("tagbak," TGK) was screened for potential anti-cancer activity against lung (A549), colorectal (HCT116) and liver (HEPG2) cancer cells.

The ethanolic leaf extract of Alpinia elegans significantly inhibits cellular proliferation and migration at high concentrations, with direct exposure-response relationship within concentrations.

An ethanolic extract (TGK) was prepared from A. elegans leaves sampled from Infanta, Quezon. Its anti-proliferative activity on A549, HCT116 and HEPG2 was determined using MTS cell viability assay, with doxorubicin (DXR) as positive control and 0.1% DMSO in culture media as negative control. To differentiate cytostatic from cytotoxic effects, LDH cytotoxicity was performed, with 5-fluorouracil (5-FU) as positive control. In screening for metastatic potential, scratch wound assay was done, with percent gap closure as indicator of cell migration. To visualize the actin filaments and nuclei, the cells were stained with AlexaFluor488-tagged phalloidin and Hoechst 33342, respectively.

Phytochemical analysis revealed traces of alkaloids, moderate amounts of sterols, and abundant triterpenes, flavonoids, saponins, glycosides and tannins in TGK. TGK exhibited anti-proliferative activity at high concentrations, with TGK being more effective against HEPG2 (IC50: 98.35 ppm) than A549 (IC50: 245.5 ppm) and HCT116 (IC50: 299.7 ppm). This can be attributed to the cytotoxic activity of TGK as seen in LDH release assay, with HEPG2 more affected than HCT116 or A549. TGK also attenuated cell migration, with significantly different gap closure from negative control at 500 ppm (p<0.05). Cytoskeleton and nuclei visualization via fluorescence microscopy showed cell shrinkage and pyknosis, as well as cellular debris, indicating both apoptotic and necrotic effects on cancer cells.