Essential Oil Constituents of Piper vicosanum Yunker from the Brazilian Atlantic Forest

Journal of Essential Oil Research: JEOR, Jul/Aug 2006 by Mesquita, Jussara M O, Oliveira, Alaide B, Braga, Fernão C, Lombardi, Júlio A, Et al

Abstract

The composition of Piper vicosanum Yuncker leaf essential oil from the Brazilian Atlantic Forest (Parque Estadual do Rio Doce, Minas Gerais, Brazil) was investigated. GC and GC/MS analysis of the oils from samples of two populations led to the identification of 64 constituents amounting over 93% of the total oil. The composition was dominated by monoterpenoids (56.0-62.6%), with limonene (40.0-45.5%) and 1,8-cineole (10.4-15.0%) as major compounds. This oil is clearly different from those of all other previously reported Piper leaf oils.

Keyword Index

Piper vicosanum, Piperaceae, essential oil composition, 1,8-cineole, limonene.

Introduction

The genus Piper (Piperaceae) comprises about 700 species distributed in the tropical and subtropical regions. Besides the popular condimental species P, nigrum L. (black pepper), other valuable Piper species are used all over the world in the preparation of ceremonial drinks and traditional remedies. Folk medicines of West Indies, Africa and Latin America, as well as the Indian Ayurvedic system of medicine, make use of Piper species for healing cough, bronchitis, intestinal pains, wounds, skin irritations and inflammations. Their usefulness motivated investigations of biological effects of crude extracts or isolated compounds (1-5) and justifies the interest in Piper phytochemistry. Extensive revisions have been regularly published on the chemistry oiPiper reporting the occurrence of alkaloids, amides, propenylphenols, lignanes, neolignanes, steroids, pyrones, chalcones, dihydrochalcones, flavones and terpenoids (6,7).

Volatile oils, characteristic of most species of this genus, have also been object of several studies, revealing valuable biological activities and interesting compositions with monoterpenoids, sesquiterpenoids and seldom phenyl- and arylpropanoids. Some of those studies focus on the oils of Piper species growing wild in Brazil (8-18). Nevertheless, considering die 170 Piper species (25% of the Piper diversity) estimated as growing wild in the diversified habitats of Brazil, most of the species have not be studied and their chemical and, as a result, theirpharmacological potential remains unknown. Such is the case of P. vicosanum Yuncker, a shrub that occurs in the Brazilian Atlantic Forest. The name of this species is derived from the city named "Viçosa," State of Minas Gerais, where the original specimens studied by Yuncker (19) were collected, including the holotype.

With the aim of contributing to the knowledge of Piper species chemistry from Brazil we would like to report on the composition of the oil of P. vicosanum grown in the Brazilian Atlantic Forest for which, to the best of our knowledge, no chemical data is available.

Experimental

Plant material: Two samples of P. vicosantt m were collected within the limits of the Brazilian Atlantic Forest: one sample ( sample A ), collected in November 1999, is representative of a wild population growing in the protected area of Rio Doce State Park (Parque Estadual do Rio Doce, State of Minas Gerais, Brazil, 19°41'-19°30'S and 42°38' -48°28'W); the other (sample B), collected November, 2001, is representative of a semi-wild population growing in the Campus Pampulha, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Voucher specimens were deposited in the Herbarium of the Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, registered under the references BHCB 49608 and BHCB 23266, respectively.

Essential oils isolation: Plant samples were air dried for 10 days and aerial parts submitted to water for 3 h using a Clevenger-type apparatus, according to the procedure described in the European Pharmacopoeia (20). The obtained oils were stored at 4°C in the dark prior to analysis.

Gas chromatography (GC): Analytical GC was carried out in a Hewlett Packard 6890 (Agilent Technologies, Palo Alto, CA, USA) gas chromatograph with HP GC ChemStation Rev. A.05.04 data handling system, equipped with a single injector and two flame ionization detectors (FID). A graphpak divider (Agilent Tecnologies, Part Number 5021-7148) was used for simultaneous sampling to two Supelco (Supelco Inc., Bellefont, PA, USA) fused silica capillary columns with different stationary phases: SPB-1 (30 m x 0.20 mm, film thickness 0.20 µm), and SupelcoWax 10 (30 m x 0.20 mm, film thickness 0.20 µm). Oven temperature program: 70°-220°C (3°C/min), 220°C (15 min); injector temperature: 250°C; carrier gas: He, adjusted to a linear velocity of 30 cm/s; injection: split mode, 1:40; injected volume: 0.2 µL, of pentane sample solution (1:8); detectors temperature: 250°C.

Gas chromatography/mass spectrometry: Analyses were carried out in a Hewlett Packard 6890 gas chromatograph fitted with a HPl fused silica column (30 m x 0.25 mm, film thickness 0.25 µm), interfaced with an Hewlett Packard mass selective detector 5973 (Agilent Technologies, PaIo Alto, CA, USA) operated by an HP Enhanced ChemStation software, version A.03.00. GC parameters as above; interface temperature: 250°C; MS source temperature: 230°C; MS quadrupole temperature: 150°C; ionization energy: 70 eV; ionization current: 60 µA; scan range: 35-350 u; scans/s: 4.51.