Chemical diversity and leishmanicidal activity of Manekia obtusa Miq (Piperaceae)

Abstract

Piperaceae species have long been used for therapeutic purposes, a reason for the great interest in their use as a source of raw material in phytochemical studies. The aim of this work is to investigate the chemical composition and biological potential of Manekia obtusa Miq, a native rare Piperaceae species in Brazil. Phytochemical studies of nonpolar extract from leaves of M. obtusa led to the isolation and characterization of the flavone 7,4'-dimethylapigenine and 2', 6'-dihydroxy-4'-methoxychalcone from the hexane extract. This flavonoid rich fraction was able to inhibit both growth and viability of Leishmania amazonensis in a dose dependent way. Minimum inhibitory concentration (MIC) and inhibitory concentration of 50% (IC50) were calculated at 49.25 and 26.03 μg/ml, respectively. The leaves and stems of M. obtusa had their essential oils extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The constituents δ-3-carene (55.3%), α-pinene (5.9%), δ–cadinene (2.9%), β-pinene (2.7%) and α-cadinol (2.5%) were identified as the major components of the leaf essential oil, while in the stems, δ-3-carene (46.2%) was the major constituent followed by safrole (9.3%), α-cadinol (3.5%), b-pinene (3.2%) and α-pinene (3.1%). These results contributed to improving the knowledge of this native species rarely studied in Brazil. All compounds have not been previously been described with respect to this species. Key words: Manekia obtusa, Piperaceae, Manekia, essential oil, flavonoids.