Antiproliferative and photoprotective activities of the extracts and compounds from Calea fruticosa

T.M.Q Seregheti,V.M.R Dos Santos,A.Dos S Antunes,A.M Do Nascimento,A.P.R Pinto,W.A.Da S Almeida,J.N Silva,R.S Machado,M.Da C Gonçalves,P.M.P Ferreira,C Pessoa

doi:10.1590/1414-431x20209375

Abstract

In this paper, we complement our previous study on the antiproliferative activity of Calea fruticosa (Asteraceae) by isolating the compounds apigenin-4',7-dimethyl ether (1), budlein A (2), quercetin (3), and cichoriin (4) from the plant’s aerial parts. The antiproliferative activity of these compounds was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method against human tumor cell lines. Compound 3 displayed moderate antiproliferative activity in three cell lines (HCT-116, PC-3, and SF-295, with cell growth inhibition values of 72.97, 74.55, and 68.94%) and high antiproliferative activity (90.86%) in the HL-60 cell line. The in vitro sun protection factor (SPF) of the extracts and compound 4, with and without sunscreen, was determined by a spectrophotometric method. The ethanol extract exhibited the highest SPF (9.67) at a concentration of 0.100 mg/mL, while compound 4, isolated from this extract, showed a SPF of 13.79 at the same concentration. A relative increased efficacy of SPF was observed for the extracts and compound 4 when sunscreen was also used. Compound 4 has not been reported previously from any species within the genus Calea. Compounds 1–4 were obtained from this species for the first time.

Highlights

Exposure to ultraviolet radiation has been implicated as a major causative agent and a risk factor for skin cancer [1]
This paper represents the first study on the secondary metabolites of C. fruticosa
This study evaluated the antiproliferative action of 3 major compounds: budlein A [2], quercetin [3], and cichoriin [4], isolated from active C. fruticosa extracts, using the in vitro MTT method

Summary

Introduction

Exposure to ultraviolet radiation has been implicated as a major causative agent and a risk factor for skin cancer [1]. Reducing the amount of UV electromagnetic radiation that reaches the skin with sunscreens may reduce the risk of sunlight-induced skin cancer [3]. The use of plant extracts as an efficient strategy to protect against skin photoaging is growing. Many of these extracts have compounds with photoprotective or synergistic activity in association with sunscreens, in addition to their high antioxidant potential [4]. Natural compounds from various sources offer a great opportunity for discovery of novel therapeutic candidates and plants have a long history of use in the treatment of cancer. Active constituents of Catharanthus roseus (Apocynaceae), Angelica gigas (Apiaceae), Podophyllum peltatum (Berberidaceae), Taxus brevifolia (Taxaceae), Ochrosia elliptica (Apocynaceae), Calea fruticosa and biological activities and Camptotheca acuminata (Cornaceae) have been used in the treatment of advanced stages of various malignancies [7]

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Conclusion