Propolis obtained in a clearing inside the Atlantic Forest in Ubatuba (São Paulo state, Brazil): essential oil and possible botanical origin

Abstract

Propolis is a honey bee product containing resin derived from plants. It has been shown that propolis protects beehives against infections and enhances their immunity. The honey bee favorite source of resin for propolis production in southeast Brazil is Baccharis dracunculifolia (Asteraceae), a species not adapted to grow inside forests. Colonies of Africanized honey bees were placed in a clearing inside the Atlantic Forest in Ubatuba (São Paulo state, Brazil), aiming to obtain a distinct type of propolis, containing resin derived from local plants. It was expected that the chemical composition of the propolis could afford means to suggest likely plant sources of resin. Propolis was eventually obtained, from which a volatile oil was extracted by steam distillation and analyzed by GC-EI-MS. Thirty-one constituents were characterized, among them some typical constituents of Baccharis dracunculifolia, which, however, appeared as minor constituents. The most abundant components of the oil were benzyl benzoate (45.3%) and benzyl salicylate (10.04%). Both volatile esters have been detected in volatile oils from species of Peperomia and Piper. The essential oil of Peperomia tetraphylla, an epiphytic herb inhabiting the Atlantic Forest, contains benzyl benzoate and benzyl salicylate in proportions close to the oil of the propolis obtained. Both phytogeography and chemical composition are consistent with Piper or Peperomia species as the resin source of the propolis analyzed. This is the first report pointing out species of Piperaceae as likely origin of propolis.