Phytochemical Profiling and Assessment of Anticancer Activity of Leptocarpha rivularis Extracts Obtained from In Vitro Cultures.

Julia Rubio,Guisselle Arias,Andrés F Olea,Evelyn Silva-Moreno,Luis Espinoza,Christian Robles-Kelly,Héctor Carrasco

doi:10.3390/plants11040546

Abstract

Plant cell culture is a source of plant material from which bioactive metabolites can be extracted. In this work, the in vitro propagation of Leptocarpha rivularis, an endemic Chilean shrub with anticancer activity, is described. Different media were tested and optimized for the introduction, propagation, and rooting steps of the micropropagation process. At the end of this process, 83% of plants were successfully acclimatized under greenhouse conditions. Callus induction from the internodal stem segment was performed using various combinations of phytohormones. Green-colored, friable, and non-organogenic callus was generated with a callus induction index higher than 90%. The chemical composition of extracts and callus, obtained from clonal plants, was assessed and the results indicate that the phytochemical profiles of extracts from micropropagated plants are like those found for plants collected from natural habitats, leptocarpine (LTC) being the major component. However, no LTC was detected in callus extract. HeLa and CoN cells, treated with LTC or extract of micropropagated plants, exhibit important diminution on cell viability and a drastic decrease in gene expression of IL-6 and mmp2, genes associated with carcinogenic activity. These effects are more important in cancer cells than in normal cells. Thus, micropropagated L. rivularis could be developed as a potential source of efficient antiproliferative agents.

Highlights

Leptocarpha rivularis DC, the common name of which is “Palo negro”, is an endemic, monotypic and dioecious species that belongs to the Asteraceae family
The chemical composition of in vitro plant extracts and callus was determined by HPLC and compared with extracts obtained from adult plants grown in natural habitats
The results indicate that both kind of extracts have a similar chemical composition, and that LTC is not present in callus extracts

Summary

Introduction

Leptocarpha rivularis DC, the common name of which is “Palo negro”, is an endemic, monotypic and dioecious species that belongs to the Asteraceae family It grows mainly in the southern part of Chile (between VII and X regions) [1], and it has been known and used for centuries as folk medicine by the Mapuche people [2]. Previous phytochemical studies of L. rivularis have shown that extracts obtained from leaves, bark, and flowers exhibit antioxidant, hypoglycemic, and anticancer effects [3,4,5,6,7] These biological activities have been attributed to the presence of sesquiterpene lactones, i.e., leptocarpine (LTC) as the major component and small amounts of rivularin and the 17,18-dihydroleptocarpin derivative [8,9,10,11]. Even though far there is no information to suggest overexploitation, some attempts at the vegetative propagation of L. rivularis have been reported [12], and in vitro clonal micropropagation has recently been described as an interesting alternative to grow it under controlled laboratory conditions [13]

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Results

Conclusion