Cytotoxic evaluation of Piper arboreum

Breast cancer is the most common type of cancer worldwide in women1. In Brazil, the National Cancer Institute (INCA) estimates the emergence of 60,000 new cases by 2018 and 2019. New therapeutic options need to be investigated for the control of this disease, due to the lack of therapeutic response to conventional treatments and the poorly tolerated adverse effects2. Many of the anticancer drugs currently employed in the clinic were derived, directly or indirectly, from natural products3.
Therefore, the present work aimed to evaluate the cytotoxic activity of a native Brazilian species, Piper arboreumand its chemical profile. This species is popularly known as “fruto de morcego” and belongs to the Piperaceae family. The genus Piper have shown antitumor activity4, therefore P. arboreum was chosen by a chemosystematic analysis that suggests that plants of the same genus can produce the same or similar secondary metabolites5. Initially, the dried leaves of Piper arboreum were extracted by maceration assisted with ultrasound, using dichloromethane as solvent. The solvent was removed by rotary evaporator. Subsequently, the cytotoxicity of the extract was evaluated against breast adenocarcinoma cells (MDA-MB-231) by sulforhodamine B colorimetric assay6. Different concentrations (250 - 1.95 µg / mL) of the extract were tested and doxorubicin was used as positive control. Piper arboreum extract showed promising results with IC50 values of 58.36 µg/mL. The chemical profile of the extracts was obtained by UPLC-DAD and it was used a C18 column (100 x 2.1 mm; 1.7 µm) and as eluent water: acetonitrile in linear gradient. The chromatogram showed the predominance of medium and low polarity substances. The UV spectra obtained on line suggested the presence of phenylpropanoid with retention time (min) of 8.75. Thus, new studies will be performed to isolate and evaluate the cytotoxic activity of Piper arboreum substances to select new candidates to be used in therapies of this cancer.

References

1. INCA- Instituto Nacional do Câncer. Disponível em: <http://www2.inca.gov.br/ >. Acesso em 17 de maio de 2019.
2. UNNATI, S.; RIPAL, S.; SANJEEV, A.; NIYATI, A. Novel anticancer agents from plant sources. Chinese Journal of Natural Medicines, v.11, n.1, p.16–23, 2013
3. CRAGG, G. M.; NEWMAN, D. J. Natural products as Sources of New Drugs from 1981 to 2014. Jounal of Natural Products, v. 79, p.629–661, 2016.
4. MACEDO, Arthur L. et al. Cytotoxicity and selectiveness of Brazilian Piper species towards oral carcinoma cells. Biomedicine & Pharmacotherapy, v. 110, p.342-352, 2019.
5. CRAWFORD, D. J.; GIANNASI, D. E.; Plant chemosystematics. BioScience, v. 32, p. 114, 1982.
6. VICHAI V, KIRTIKARA K. Sulforhodamine B colorimetric assay for cytotoxicity screening. Natural Protocols, v.1, p. 1112–1116, 2006.