Rhynchophorus palmarum (Linnaeus, 1758) (Coleoptera: Curculionidae): Guarani-Kaiowá indigenous knowledge and pharmacological activities.

Kellen Natalice Vilharva,Katia Ávila Antunes,Claudiane Vilharroel Almeida,Maria Lígia Rodrigues Macedo,Helder Freitas Dos Santos,Edson Lucas Dos Santos,Denise Brentan Silva,Caio Fernando Ramalho De Oliveira,Daniel Ferreira Leite,Kely De Picoli Souza,Paola Dos Santos Da Rocha,Jaqueline Ferreira Campos,Branislav T Šiler

doi:10.1371/journal.pone.0249919

Kellen Natalice Vilharva, Katia Ávila Antunes + Show 11 more

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https://doi.org/10.1371/journal.pone.0249919

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Abstract

Zootherapy is a traditional secular practice among the Guarani-Kaiowá indigenous ethnic group living in Mato Grosso do Sul, Brazil. My people use the oil extracted from larvae of the snout beetle Rhynchophorus palmarum (Linnaeus, 1758) to treat and heal skin wounds and respiratory diseases. Based on this ethnopharmacological knowledge, the chemical composition and antioxidant, antimicrobial, and healing properties of R. palmarum larvae oil (RPLO) were investigated, as well as possible toxic effects, through in vitro and in vivo assays. The chemical composition of the RPLO was determined using gas chromatography coupled with mass spectrometry. The antioxidant activity of RPLO was investigated through the direct 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, and the antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria that are pathogenic to humans. The healing properties of RPLO were investigated by performing a cell migration assay using human lung fibroblasts (MRC-5), and the toxicity was analyzed, in vivo, using a Caenorhabditis elegans model and MRC-5 cells, in vitro. RPLO contains 52.2% saturated fatty acids and 47.4% unsaturated fatty acids, with palmitic acid (42.7%) and oleic acid (40%) representing its major components, respectively. RPLO possesses direct antioxidant activity, with a half-maximal inhibitory concentration (IC50) of 46.15 mg.ml-1. The antimicrobial activity of RPLO was not observed at a concentration of 1% (v/v). RPLO did not alter the viability of MRC-5 cells and did not exert toxic effects on C. elegans. Furthermore, MRC-5 cells incubated with 0.5% RPLO showed a higher rate of cell migration than that of the control group, supporting its healing properties. Taken together, RPLO possesses direct antioxidant activity and the potential to aid in the healing process and is not toxic toward in vitro and in vivo models, corroborating the safe use of the oil in traditional Guarani-Kaiowá medicine.

Highlights

Traditional knowledge (TK) is the result of the secular experience of these communities living among the local biodiversity, their relationship with the environment, and their use of different species for their benefit [1,2,3,4]
While the use of animal fat in the treatment of diseases by indigenous people is part of TK, the literature describes the antioxidant properties of unsaturated and saturated fatty acids that compose the triglycerides of animals and attributes these compounds to the ability to neutralize oxidative damage [10], both after topical use and oral ingestion [11, 12]
The determination of the chemical composition revealed that R. palmarum larvae oil (RPLO) comprises saturated (SFA) and unsaturated (UFA) fatty acids, with a slightly higher SFA content

Summary

Introduction

Traditional knowledge (TK) is the result of the secular experience of these communities living among the local biodiversity, their relationship with the environment, and their use of different species for their benefit [1,2,3,4]. The practice of zootherapy is common among the Guarani-Kaiowa, records of the species used, the purposes of treatments, and the forms of drug preparation are scarce. Some of the secular knowledge related to zootherapy is transmitted to the younger generation by the Maxuypy, the matriarch of the family. In this manner, I, Kellen Natalice Villarva, a biologist, and one of the authors of this study, received part of the knowledge of my ethnicity from my grandmother. The use of Mbuku, the name given to the beetle Rhynchophorus palmarum (Linnaeus, 1758) (Coleoptera: Curculionidae), in its larval stage is part of the Guarani-Kaiowa TK, whether in its sacred tales, in its rituals or for food and medicinal purposes. While the use of animal fat in the treatment of diseases by indigenous people is part of TK, the literature describes the antioxidant properties of unsaturated and saturated fatty acids that compose the triglycerides of animals and attributes these compounds to the ability to neutralize oxidative damage [10], both after topical use and oral ingestion [11, 12]

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