Over 4,000 flavonoids have been identified, and among these, many of them are known to possess cardioprotective, anti-inflammatory, antimicrobial, and antitumor effects. However, most of these properties have yet to be fully understood. In this study, extracts from Gnaphalium gracile, thought to possess a mixture of flavonoids, have been tested for cytotoxic activity on pancreatic (MiaPaca, Panc28), colon (HCT-116, Caco-2), and prostate (PC3, LNCaP), cancer cell lines. Polar extracts from the leaves of G. gracile have the most cytotoxic effect on these cancer cell lines, particularly the prostate cancer cell lines PC3 and LNCaP. Evidence suggests the extracts have antineoplastic effects on these cancer cells lines possibly due to differentiation status on pancreatic and colon cancer, but not prostate cancer. Cytotoxic activity is not dependent on tumorigenic potential. Further research is needed to identify the bioactive compounds within these extracts.

Ethanol and n-hexane extracts obtained from the leaves and inflorescences of Gnaphalium gracile, were tested at different concentrations to evaluate their antineoplastic activities on pancreatic, colon, and prostate cancer cell lines by examining mitochondrial function. The polar extracts of both, leaves and inflorescences which contain gnaphalin, quercetin, and 3-methoxy quercetin, exhibited cytotoxicity against every cell line tested with EC50 values ranging between 20.23±1.185 µg/mL and 70.71±1.1419 µg/mL. The most remarkable values were observed in pancreatic cancer Panc 28 and androgen-dependent prostate LnCaP cells, with EC50 values of 20.23±1.185 and ˂25µg/mL, and androgen-independent prostate cancer PC-3, colon HCT-116 and pancreatic MIA PaCa cells with values ranging between 28.84±1.1766 and 34.41±1.057 µg/mL. The non-polar extract derived from leaves demonstrated significant cytotoxicity towards colon cancer HCT-116 cells, with an EC50 of 39.46±1.0617 µg/mL. However, the non-polar extract from the inflorescences did not have an appreciable effect on cell proliferation of any of the cell lines tested except for androgen-independent prostate cancer PC-3 cells with an EC50 of 62.05±1.237 µg/mL. The data obtained support the traditional use of G. gracile and suggest the polar extracts from aerial parts, as an interesting source for the development of novel antineoplastic agents.