Table 1.

Inhibitory effects of Piper genus-derived compounds on human cancer cell viability.

Compound	IC50 (μg/mL)
	U373 Cells	MCF7 Cells
Gibbilimbol B	16.79	16.44
Eriopodol A	11.12	10.12
Eriopodol B	31.91	29.36
Eriopodol C	14.30	16.30
Erioquinol	1.78	2.63

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed treating cells for 24 h in the absence (vehicle) or in the presence of increasing concentrations of Piper genus-derived compounds. The results have been obtained in four independent experiments.