Cytotoxic and antileishmanial triterpenes of Tabebuia aurea (Silva Manso) leaves

The bioactivity-guided fractionation of the total ethanolic extract of the leaves of Tabebuia aurea revealed the cytotoxic and antileishmanial potency of the ethyl acetate fraction, in which its phytochemical investigation resulted in the isolation of five triterpenes; identified as oleanolic acid (1), ursolic acid (2), pomolic acid (3), tormentic acid (4), 3 beta,6 beta,19 alpha-trihydroxy-urs-12-en-28-oic acid (5) in addition to one triterpenoid glucoside, spathodic acid 28-O-beta-D-glucopyranoside (6). Whereas compound 1 showed cytotoxic activity against three different cell lines; A549, MCF-7 and HepG2 with IC50 values of 31.7 +/- 1.2, 27.4 +/- 1.8 and 28.8 +/- 1.1 mu g/mL, respectively (etoposide as a positive control: 28.1 +/- 4.2, 22.5 +/- 4.5, and 20.4 +/- 0.8 mu g/mL, respectively), while compounds 1 and 2 showed antileishmanial activity with IC50 values of 10.2 +/- 0.9 mu g/mL and 5.1 +/- 0.4 mu g/mL, respectively (miltefosine: 7.7 +/- 2.1 mu g/mL).

Automated summary

The bioactivity-guided fractionation of the leaves of Tabebuia aurea resulted in the identification of ethyl acetate fraction with cytotoxic and antileishmanial activity. Five triterpenes and one triterpenoid glucoside were isolated from this fraction. Compound 1 showed cytotoxic activity against multiple cell lines, while compounds 1 and 2 exhibited antileishmanial activity.