Antiproliferative effect of extracts and pyranonaphthoquinones obtained from Cipura paludosa bulbs

Context: Cipura paludosa Aubl. (Iridaceae) is widely used in folk medicine to treat several ailments. Experimental studies have confirmed its anti-inflammatory, antinociceptive, and neuroprotective effects. Objective: This study evaluates the possible antiproliferative potential of the crude methanol extract and three isolated compounds from the bulbs of C. paludosa. Materials and methods: Phytochemical analysis was carried out by conventional chromatographic techniques, and the resulting compounds were identified by NMR 1 H and 13 C. The antiproliferative activity was analysed using the sulforhodamine B assay. Results: Crude methanol extract of C. paludosa bulbs showed GI 50 values of between 1.6 and 30.8 μg/mL. The naphthoquinone derivatives (eleutherine, isoeleutherine, and eleutherol) isolated from the bulbs of C. paludosa exhibited promising cytotoxicity against several human tumour cell lines, especially the two main compounds, eleutherine and isoeleutherine, against glioma and breast cancer cell lines, with TGI values of between 2.6 and 13.8 μg/mL. Conclusion: Cipura paludosa bulbs produce active principles with relevant antiproliferative potential, such as naphthoquinone derivatives, identified as eleutherine, isoeleutherine, and eleutherol. This is the first report indicating C. paludosa with antiproliferative potential.