Chemical Composition, Antioxidant and Anticancer Activities of Leptocarpha rivularis DC Flower Extracts.

Iván Montenegro,Carlos Jara-Gutiérrez,Enrique Werner,Joan Villena,Manuel Valenzuela,Fernando Dorta,Alejandro Madrid,Michael Seeger,Juan Felipe Alfaro,Ociel Muñoz,Ingrid Ramírez,Matias Alvear,Elizabeth Sánchez,Jorge Moreira

doi:10.3390/molecules26010067

Abstract

An evaluation of antioxidant and anticancer activity was screened in Leptocarpha rivularis DC flower extracts using four solvents (n-hexane (Hex), dichloromethane (DCM), ethyl acetate (AcOEt), and ethanol (EtOH)). Extracts were compared for total extract flavonoids and phenol contents, antioxidant activity (2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric reducing antioxidant potential (FRAP), total reactive antioxidant properties (TRAP) and oxygen radical absorbance capacity (ORAC)) across a determined value of reduced/oxidized glutathione (GSH/GSSG), and cell viability (the sulforhodamine B (SRB) assay). The most active extracts were analyzed by chromatographic analysis (GC/MS) and tested for apoptotic pathways. Extracts from Hex, DCM and AcOEt reduced cell viability, caused changes in cell morphology, affected mitochondrial membrane permeability, and induced caspase activation in tumor cell lines HT-29, PC-3, and MCF-7. These effects were generally less pronounced in the HEK-293 cell line (nontumor cells), indicating clear selectivity towards tumor cell lines. We attribute likely extract activity to the presence of sesquiterpene lactones, in combination with other components like steroids and flavonoids.

Highlights

Leptocarpha rivularis DC, locally known as “palo negro”—or, in Mapudungun, Cüdu-mamëll, originally named by the Mapuche people of Chile—is a perennial shrub native to southern Chile which grows in humid and sunny soils up to two meters in height, with toothed-edged leaves up to 10 cm
Based on its potential for antioxidant and cytotoxic activities, L. rivularis DC flower extracts have been assessed for the first time
Flower extracts demonstrated selective cytotoxicity and a caspase induction causing cell death, which suggests that L. rivularis

Summary

Introduction

Leptocarpha rivularis DC (family, Compositae; tribe, Heliantheae; presently classified as Asteraceae), locally known as “palo negro”—or, in Mapudungun, Cüdu-mamëll, originally named by the Mapuche people of Chile—is a perennial shrub native to southern Chile which grows in humid and sunny soils up to two meters in height, with toothed-edged leaves up to 10 cm. It is a typical species of the “Valdivian forest”, distributed from the Region of Maule to the Region of Los Lagos, it grows in the coastal and Andean mountain ranges [1]. Peripheral, flowers, Molecules 2021, 26, x FOR PEER REVIEW the ovary is atrophied and the remaining parts of the flower are completely missing. 3Inofthe central, or discoidal, flowers, there are two distinct groups: male flowers and female flowers

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