Abstract Casearborin c (1), syringic acid (2), ent-3β-hydroxy-(-)-13-epi-manoyl oxide (3), ent-(-)-13-epi-manoyl oxide (4), ent-(-)-kaur-16-en-19-oic acid (5), and γ-sitosterol (6) were isolated from Casearia corymbosa stem bark. Only casearborin c showed cytotoxic activity on HeLa and SiHa cancer cell lines. This work contributes to the description of three compounds (1-3) newly isolated from C. corymbosa and highlights that casearborin c, a clerodane-type diterpene, is responsible for the cytotoxic activity shown in the original methanol extract of this species.

Resumen Casearborina c (1), ácido siríngico (2), óxido de ent-3β-hidroxi-(-)-13-epi-manoilo (3), óxido de ent-(-)-13-epi-manoilo (4), ácido ent-(-)-kaur-16-en-19-oico (5) y γ-sitosterol (6) se aislaron de la corteza del tallo de Casearia corymbosa. Sólo casearborina c mostró actividad citotóxica en las líneas de células cancerígenas HeLa y SiHa. Este trabajo describe tres compuestos (1-3) aislados por primera vez de C. corymbosa y destaca que casearborina c, un diterpeno de tipo clerodano, es responsable de la actividad citotóxica del extracto metanólico de esta especie.

AbstractAphelandra scabra (Vahl) Sm., Acanthaceae, is a shrub widely used by some Mayan communities as carminative, antidote, and remedy for some infections. Bio-guided isolation of the methanol extract of leaves led us to the purification of the anti-giardial metabolites cirsimaritin and sorbifolin, along with the inactive metabolites cirsimarin, sorbifolin-6-O-β-glucopyranoside, and squalene. Cirsimaritin displayed high activity in the anti-giardial bioassay with an IC50 = 3.8 μM, being considered as outstanding when compared to previous reported metabolites, while sorbifolin showed a low activity with an IC50 = 75.6 μM. Additionally, both compounds proved not to be cytotoxic in an in vitro bioassay against HEK-293, a normal cell line. This is the first investigation on anti-giardial properties of A. scabra and its phytochemistry as well, thus the isolated compounds are considered as new for the plant genus and for the species.