Report on the Malungo expedition to the Erepecuru river, Oriximiná, Brazil. Part I: is there a difference between black and white breu?

ABSTRACT

ABSTRACT Species belonging to Burseraceae produce an oleoresin known in the north of Brazil as breu. They comprise an essential oil with a complex composition, and are used in Amazonia for smoking the environment, to caulk boats and for medicinal purposes. Depending on its organoleptic characteristics and on the breu-producing species, they are called white or black breu. In this work, we provide data about the breu-producing species occurring in the quilombola region of the Erepecuru river, the chemical composition, and whether it is possible to differentiate them based on their chemical composition and/or botanical identification. Aerial samples from breu trees and oleoresins were collected from 10 different individuals at 6 different sites on the Erepecuru river under the guidance of the quilombolas. Essential oils were extracted by hydrodistillation and characterized by GC–MS. From the analysis, 126 different substances were identified, with a large quantitative and qualitative variation. To better understand the chemical variations within the samples and to sort the variation into the categories of white or black breu as identified by the quilombola, we sorted the oil samples into five different sets according to their major compounds (A δ-3-carene; B p-cymene; C γ-cadinene/p-cymene; D limonene, β-phellandrene/α-terpineol; E α-pinene/limonene). Essential oils from samples of white breu had the highest concentration of α-pinene, while a similarity in chemical composition could not be established for the black breu samples (sets A, B and C). Furthermore, a chemical similarity between a black breu (Protium heptaphyllum (Aubl.) Marchand) and a white breu (Protium decandrum (Aubl.) Marchand) sample was evidenced. In conclusion, it is difficult to establish definitions for white and black breu based on chemical, botanical or regional names. This designation is more cultural and regional than scientific and is based on the oleoresin production volume, its color aspect and scent.