Anti-Proliferative, Antioxidant and Iron-Chelating Properties of the Tropical Highland Fern, Phymatopteris triloba (Houtt) Pichi Serm (Family Polypodiaceae)

Purpose: To determine the phenolic constituents as well as anti-proliferative, antioxidant and ironchelating activities of the leaf and rhizome extracts of Phymatopteris triloba. Methods: Concentrations of selected hydroxybenzoic acids, hydroxycinnamic acids and flavonoids in aqueous extracts were quantified using high performance liquid chromatography (HPLC). Antiproliferative activity was assessed on human cervix cancer cell line (HeLa) and human chronic myelogenous leukemia cell line (K562). Superoxide and nitric oxide scavenging activities as well as iron-chelating activity were determined colorimetrically. Results: Protocatechuic acid content of the rhizome extract (154.7 g/g dry matter (DM)) was 1.9-fold higher than in the leaf extract. p-Hydroxybenzoic acid (34.6 g/g DM) and gallic acid (18.9 g/g DM), were only detected in the rhizome extract. Sinapic acid (6.6 g/g DM) was detected in the leaf extract only. Myricetin content of leaf extract (98.5 g/g DM) was 3.7-fold higher compared with the rhizome extract. At 500 g DM/ml, both extracts produced about 40 and 30 % anti-proliferative activity on HeLa cells and K562 cells, respectively. Both extracts had moderate nitric oxide-scavenging and ironchelating activities. The leaf extract half-maximal effective concentration (EC50) value of 0.85 mg/ml (scavenging of superoxide radicals) was higher than that of ascorbic acid. Conclusion: P. triloba is a potential source of anti-proliferative, antioxidant and iron-chelating agents. Its bioactivities may be attributed to the presence of phenolic constituents.