Essential Oils from Argentinean Aromatic Plants

A research association was established between Rutgers University, USA and Argentinian Universities, National University of La Rioja and National University of Córdoba, to identify aromatic and medicinal plants of potential commercial interest for future cultivation and conservation programs. This study was part of a larger project to study the uses of native aromatic plants in commercial products in Argentina and to evaluate the content and composition of essential oils in some of the species growing wild in the Los Llanos region (La Rioja Province, midwestern Argentina). A regional market survey showed that the majority of these species are utilized commercially to prepare a wide range of commercial herbal products that include non-prescription drugs, composite yerba mate, herbal teas and non-alcoholic beverages. Lippia turbinata, locally known, as "Poleo" was the most used aromatic plant in Argentina, being found in the 38 % of commercial products, whereas, L. integrifolia (“incayuyo”) was present in 23 % of products. Chenopodium ambrosioides (“paico”) and Aloysia polystachia (“Te del burro”) were found in 5 % and A. gratissima (“Palo amarillo”) in only 1 % of commercial herbal products. The essential oil of these species and other aromatic plants from Los Llanos region (La Rioja Province) were evaluated. We found that several of the aromatic plants from this region of Argentina could serve as potential new sources of essential oils. In addition, the volatile oils of Lippia salsa and Larrea divaricata are described for the first time. INTRODUCTION In Argentina, local people commonly use aromatic plants in popular medicines and as beverages (Soraru and Bandoni, 1978). As a consequence, this important group of the native flora is found in a wide variety of commercial products (Zygadlo and Juliani, 2002). In recent years, there appears to be a significant increase in their consumption and demand. Since very few of the native species are cultivated, nearly all are collected from the wild to meet the growing demands of industry. As a result, natural populations are declining and genetic diversity has been lost, and the scientific and environmental communities are concerned that further genetic losses will be witnessed in the future without purposeful intervention (Oni, 1993). Prior work showed that many of the therapeutic effects of these species in their local applications could be attributed predominantly or even exclusively to their essential oils (Trease and Evans, 1986). Essential oils extracted from plants have long been used in foods, flavorings and fragrances (Williams, 1997). Those plants, which provide new and unique fragrances and Proc. XXVI IHC – Future for Medicinal and Aromatic Plants Eds. L.E. Craker et al. Acta Hort. 629, ISHS 2004 Publication supported by Can. Int. Dev. Agency (CIDA) 492 aromas, have potential for commercialization as new crops either as culinary herbs, aromatic teas, or as sources of extractable essential oils (Simon, 1990). A research association was established between Rutgers University, USA and Argentinian Universities, National University of La Rioja and National University of Córdoba, to identify aromatic and medicinal plants of potential commercial interest for future cultivation and conservation programs. The aim of this work was to study the uses of native aromatic plants in selected commercial products in Argentina and to evaluate the content and composition of essential oils in some of this species growing in Los Llanos region (La Rioja Province, Midwestern Argentina). MATERIAL AND METHODS A regional market survey of local supermarkets was conducted. In total 82 commercial products were found being sold in supermarkets containing one or more native aromatic plants. The commercial products containing native herbs were clustered into four main groups of products (non-prescription drugs, composite yerba mate, herbal teas, and non-alcoholic beverages). The collection of products and relative popularity or use of the herb was expressed as a percentage that the given aromatic species was present in a given group of products or in the whole set (Table 1). The volatile essential oils from plants growing in the wild in the region of "Los Llanos" (La Rioja Province, Midwestern Argentina) were extracted by steam distillation. The volatile oil was analyzed by a gas chromatograph (GC) coupled to a mass spectrometer (MS) and Flame ionization detectors (FID) (Agilent GC System 6890 Series, Mass Selective Detector, Agilent 5973 Network, FID detector). Samples were injected with an autosampler (Agilent 7683 Series), the Inlet temperature was 220 °C., in a HP5MS (30 m, 0.25 ID, 0.25 mm) column, temperature program, 60 °C 1 min, 4 °C/min, 200 °C 15 min. Helium constant flow was set at 1 ml/min. Individual identifications were made by matching their spectra with those from mass spectral libraries (Wiley 275.L). Components were listed in order of elution in HP5 (DB5 equivalent) column. The native species included in this study were Aloysia grattissima, Aloysia polystachia, Chenopodium ambrosioides, Lippia integrifolia, Lippia salsa, Lippia turbinata, Larrea divaricata. Voucher specimens were deposited at the “Herbario Regional de Chamical” (IZAC) National University of La Rioja. RESULTS AND DISCUSSION Commercial Uses of Aromatic Plants in Argentina The market survey showed that the majority of these species are utilized commercially to prepare a wide range of commercial product that include nonprescription drugs, composite yerba mate, herbal teas and non-alcoholic beverages (Table 1). Non-prescription drugs are made by packages containing 10-50 g of dried plant parts (usually the leaves of single species) that are used in popular medicine, mainly as digestive, diuretic anti-inflammatory, laxative, among others. In general, they are predominately composed of Lippia turbinata, locally known as "Poleo" and Lippia integrifolia known as "incayuyo" (Table 1). The composite yerba mate is a mixture of Ilex paraguariensis leaves (generally consisting of 85-95 % of the total product) that is utilized for the preparation of the traditional beverage “mate.” These products were often blended with of native aromatic plants for flavor (from 5-15 % of total product weight), of which L. turbinata was also found in almost 90 % in this group of products (Table 1). Herbal teas are made in tea bags containing 1.5-3 g of dry aromatic plants that are used not only for medicinal purposes (mainly digestive) but also for flavoring. They were found to be composed of a single native species or as a mix of several native and/or foreign aromatic plants including but not limited to Mentha sp (Mint), Matricaria recutita (Chamomile), Cinnamomum zeylanicum (Cinnamon) and Pimpinella anisum (Anise). In herbal teas, the native plants were a minority group, L. turbinata and L. integrifolia and