Antimicrobial and antileukemic effects: in vitro activity of Calyptranthes grandifolia aqueous leaf extract

ABSTRACT

Natural products are still a promising source of bioactive molecules. Food and Drug Administration data showed that approximately 49% of the approved molecules originate naturally or chemically-resemble these substances, of which more than 70% are being used in anticancer therapy. It is noteworthy that at present there are no scientific studies to prove the effectiveness and safety of a number of plants used in folk medicine such as in the case of Calyptranthes grandifolia O. Berg (Myrtaceae) originally from South America. The aim of the present study was to determine the biological potential and toxicological effects of the aqueous leaf extract of C. grandifolia. The main detected phytoconstituents were condensed tannins and flavonoids and a high quantity of polyphenols. Regarding the antimicrobial potential, the extract exerted inhibitory activity against Pseudomonas aeruginosa. The results also revealed the extract induced DNA damage in a concentration-dependent manner in RAW 264.7 cells. In addition, C. grandifolia produced cytotoxicity in leukemia cell lines (HL60 and Kasumi-1) without affecting isolated human lymphocytes but significantly inhibited JAK3 and p38α enzyme activity. Taken together, these findings add important information on the biological and toxicological effects of C. grandifolia, indicating that aqueous extract may be a source of natural antimicrobial and antileukemic constituents.

KEYWORDS:

• Antibacterial
• bioactive natural products
• cytotoxicity
• leukemia
• Myrtaceae

Acknowledgments

RP and MIG conceived and designed the experiments. SB, BWM, SMI, DF, GVH, HFVT performed the mammalian cell experiments. CA, JS, and SP performed the microbiological studies. SMI, DF, MIG performed the cell-free experiments. AAB and RCVS designed and performed the HPLC analysis. SB, FM, CFVS, RP, and MIG analyzed the data. SB, FM, BWM, and MIG wrote the paper. RCVS, CFVS, EJP-G, JRO, RP, JAPH, and SL critically revised the manuscript and contributed reagents/materials/analysis tools.

Declaration of interest

No potential conflict of interest was reported by the authors.

Ethical approval

“All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.”

Additional information

Funding

This work was supported by Universidade do Vale do Taquari (Univates); the National Counsel of Technological and Scientific Development (CNPq-Brazil) [grant number 445645/2014-8 and 311655/2017-3] and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) [Finance Code 001].Language proof-reading was carried out by Kristine Schmidt.