Antiprotozoal activity of essential oils derived from Piper spp. grown in Colombia

Abstract

Plant species of the genus Piper are widely distributed throughout the Colombian territory. Eleven Piper spp. essential oils (EO1–EO11) were chemically characterized and tested against Trypanosoma cruzi, Leishmania (Leishmania) infantum and mammalian cells using standard in vitro assays. The selectivity index (SI) was calculated by the ratio of CC₅₀ host cells to IC₅₀ parasites. The EO from Piper var. brachypodom, obtained from two different locations (EO10 and EO11) in Chocó (Colombia), was active on the T. cruzi. It inhibited growth of epimastigotes (EO10: IC₅₀ 0.34 μg/mL; SI: 89.82) and amastigotes (EO11: IC₅₀ 22.72 μg/mL; SI: 2.31). EO11 was active against Leishmania (L.) infantum promastigotes (IC₅₀ 23.68 μg/mL; SI: 2.65), and less active on amastigotes (IC₅₀ 62.82 μg/mL). The EO10’s major component was trans-β-caryophyllene, which inhibited the T. cruzi (IC₅₀ 24.54 μg/mL) and L. the infantum (IC₅₀ 53.39 μg/mL), intracellular forms with some toxicity on Vero (CC₅₀ 12.93 μg/mL) and THP-1 (CC₅₀ 143.85 μg/mL). α-Pinene, the main constituent of Piper bredermeyeri, was active against the T. cruzi epimastigotes (IC₅₀ 2.74 μg/mL; SI: 4.22) and amastigotes (IC₅₀ 1.92 μg/mL; SI: 6.02). Linalool, limonene, 1,8-cineole and safrole were not active on intracellular parasites. The low SI obtained with both Piper brachypodon and trans-β-caryophyllene indicates a narrow window in their parasite-specific activity. Novel formulations contained active EOs or components could be designed in order to avoid toxicities and improve the cell internalization.

Keywords:

• Piper
• cytotoxicity
• essential oil
• trans-β-caryophyllene
• Trypanosoma cruzi
• Leishmania (Leishmania) infantum

Acknowledgements

The authors would like to thank the Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología “Francisco José de Caldas” COLCIENCIAS, (Grant 432-2004 CENIVAM) and Universidad Industrial de Santander, Bucaramanga, for financial support. The authors thank Laura Viviana Herrera for her assistance in the biological testing.