Chemical Constituents, Antiproliferative and Antioxidant Activities of Vernonanthura nudiflora (Less.) H. Rob. Aerial parts

Abstract

Sesquiterpene lactones are an important class of secondary metabolites frequently isolated from Vernonanthura genus that present a variety of biological properties, including antiproliferative activity. Due to the limitation of pharmacological studies on Vernonanthura nudiflora, the aim of this work was to investigate their antioxidant potential and antiproliferative activity against human tumor cells, as well as to isolate and identify the chemical constituents present in their aerial parts. The phytochemical investigation resulted in the isolation of the sesquiterpene lactones piptocarphins A, B, D, and a new hirsutinolide derivative, 8α-tigloyloxy-10α-hydroxy-hirsutinolide, besides triterpenes, glycosylated steroids, flavonoids, and one chlorogenic acid derivative. Also, other sesquiterpene lactones were identified by ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) from dichloromethane fraction. This fraction showed activity against the tumor cells tested, mainly against leukemia, glioma, ovarian and kidney, with growth inhibitory activity (GI50) less than 0.80 μg mL-1. Piptocarphins A and B, in mixture, showed strong activity against all human cancer cell lines tested, with GI50 values ≤ 0.15 μg mL-1. Piptocarphin D was selective for glioma and resistant ovarian cell lines. The new hirsutinolide derivative showed potent activity against breast (GI50 = 0.96 μg mL-1) and resistant ovarian (GI50 = 3.60 μg mL-1) cell lines.