Anti-inflammatory, cytotoxic and antimicrobial activities of Piper peltatum leaf extract

Piper peltatum L. (syn. Lepianthes peltata (L.) Raf. Ex R.A. Howard) is a plant belonging to the Piperaceae family widely distributed in the Caribbean and in tropical America regions. Leaves of P. peltatum are widely used in traditional medicine of tropical Amazonian (Peru, Bolivia and Brazil) and Caribbean regions to treat inflammation, fever, hepatitis, malaria and infectious diseases [1]. In current study, solvent extracts of P. peltatum leaves were evaluated for their anti-melanoma (A375 metastatic melanoma cell line), anti-leukaemia (K562 chronic myeloid leukemia cell), antimicrobial activities as well as for their ability to block activation by LPS lipopolysaccharides (LPS) of two major inflammatory pathways nuclear factor-kappa B (NF-KB) and activator protein 1 (AP1) in a macrophage lineage [2]. The results show that cyclohexane and dichloromethane-methanol (1:3, v/v) extracts inhibit both NF-KB and AP1 transcription factors (Figure 1), while only dichloromethane-methanol extract was cytotoxic against A375 melanoma and K562 cells.

Fig. 1: Phosphatase alkaline activity of control (without extract), cyclohexane, dichloromethane/methanol (DCM/MeOH, 1:3, v/v), and hydroalcoolic (H₂O/MeOH, 1:1, v/v) extracts of L. Peltatum with (+) or without (-)

Antimicrobial screening of the crude extracts also underline the dichloromethane-methanol extract as the most active. It presents a high antibacterial activity (85% of inhibition) against resistant strain of Staphylococcus aureus RN4220 and a slight antibacterial activity against S. aureus S25 at 12 µg/mL. Bioguided fractionation using C18 solid phase extraction cartridge and molecule isolation by semi-preparative liquid chromatography led to the identification of three active metabolites: 4-nerolidylcatechol (1) and two compounds for the first time described P. pelatatum gonzalitosin I (2) and sesamin (3).

Keywords: Piper peltatum, anti-inflammatory, anti-melanoma, anti-leukaemia, anti-microbial, bioguided fractionation.

References:

[1] Lans C, Harper T, Georges K, Bridgewater E. Medicinal and ethnoveterinary remedies of hunters in Trinidad. BMC Complement Altern Med 2001; 1: 10

[2] Tanti JF, Ceppo F, Jager J, Berthou F. Implication of inflammatory signaling pathways in obesity-induced insulin resistance. Front Endocrinol (Lausanne) 2013; 3: 181

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