Abstract

Researchers from several Colombian universities have joined efforts for over 15 years to characterize the composition and biological properties of more than a thousand samples of essential oils (EOs) obtained from aromatic plants collected during at least 30 botanical outings in different regions of Colombia. This chapter presents a brief description of essential oil extraction and chemical characterization techniques, followed by a representative list of references to publications on EO composition obtained from tropical aromatic plants that grow in Colombia. Opportunities for the development of interesting products for the pharmaceutical, cosmetics, hygiene, and food industries are illustrated with a few selected works on the evaluation of cytotoxicity, antioxidant, antiviral, antigenotoxic activities, and repellence of these essential oils.

Keywords: Lippia, CENIVAM , antioxidant, antigenotoxic, antiviral, repellence

## 1. Introduction

Colombia, located at South America's northwest, has coasts on the Caribbean and the Pacific Ocean, extensive prairies and mountains with many forests, wild pastures and cultivated land, rivers, and lakes. The country is rich in many natural resources and water. Contrasting landscapes and varied climatic conditions have made it after Brazil, the second most biodiverse country. This biodiversity includes medicinal and aromatic plants; most native aromatic plants remain unexamined. The aromatic herbs and spices commonly used in everyday life were brought to Colombia by the Spanish conquerors five centuries ago (basil, chamomile, mint, parsley, oregano, rosemary, sage, thyme, etc.); some (citronella, lemongrass, clove, ginger, cinnamon) were introduced later, in the last two centuries.

The extension of land cultivated with medicinal and aromatic plants more than doubled between 2007 (1253 ha) and 2015 (2709 ha) [1]. These plantations are located mainly in the Andean region, some in the Eastern Plains of Colombia. The crop of medicinal and aromatic plants amounted to 16,188 tons in 2015. This vegetal material was used for many applications different from essential oil (EO) extraction, in over 100 companies and 2500 commercial establishments [1]. Aromatic plants are used in Colombia's food industry for beverages, and a portion of the crop is exported in fresh (8288 tons in 2017) [2]. Colombia has currently no commercial enterprise dedicated to the cultivation of aromatic plants destined to produce

essential oils for export or the national market. Brazil, India, China, Indonesia, and the United States are Colombia's main essential oil suppliers. In 2017, the total cost of the country's essential oil imports was 14.289 million dollars, while the country exported just 298 thousand dollars [2]. Since there is no essential oil production, the EO exported amounts corresponded to commercialization of previously imported oils.

eucalyptus), or in the trichomes (many plants of Labiatae, Asteraceae, Solanaceae, Geraniaceae families). The plant material (aromatic plant), when subjected to water vapor, releases a liquid odoriferous mixture (EO) of various volatile substances; this mixture can have from 50 to more than 300 chemical substances and is composed of terpene hydrocarbons, their oxygenated derivatives, alcohols, aldehydes, and ketones, as well as ethers, esters, phenolic compounds, phenylpropanoids, and

Study of Essential Oils Obtained from Tropical Plants Grown in Colombia

DOI: http://dx.doi.org/10.5772/intechopen.87199

EOs can be obtained from plant material by three main methods (Figure 1). (1) Steam distillation. This process is carried out with a superheated dry steam, usually generated by a boiler or steam generator, which penetrates the plant material at higher than atmospheric pressure; the steam current breaks the cells or oil channels in the plant and drags the volatile mixture, which condenses after passing through a cooling system (heat exchanger). Generally, the oils are lighter than water and with very little soluble in it; therefore, they can be separated by decantation. The exception is the clove oil, which is heavier than water and is collected under it. The steam distillation method is used to extract oils from rhizomes, roots, seeds (vetiver, valerian, ginger, anise, cardamom, etc.), and dried or fermented leaves of some plants (e.g., patchouli). (2) Distillation with watersteam. In this extraction system, wet steam is used, coming from the boiling water, which passes through the plant material suspended above and supported on a mesh. Most herbaceous plants are distilled by this method. (3) Hydro-distillation is a process in which the plant material is directly immersed in water, heated to a boil. This method is used for the distillation of more delicate plant material, for example, flowers (e.g., ylang-ylang, roses). The citrus peel (orange, tangerine, lime) EOs are also obtained by cold-pressing or by scraping their surfaces. The mixtures obtained by the methods mentioned above are called "essential oils"; other products, isolated by maceration in different solvents or with supercritical fluid (CO2), are generally called "extracts" and not "oils"; among them are concrete—obtained

other derivatives [3].

Figure 1.

121

Main methods of essential oil isolation.

The publication of Colombian scientific articles on EO research started in 1974 and grew slowly during the following 30 years (less than three articles per year). The transition point was marked by the creation in 2005 of a network of research groups that joined their expertise around the development of the EOs agroindustry. The Research Center of Excellence for the Agroindustrialization of Aromatic and Tropical Medicinal Species (CENIVAM), under technical and administrative coordination at the Industrial University of Santander (Bucaramanga), has been a leader in aromatic plants and EO studies in Colombia for more than a decade. Over 250 scientific articles comprise the results of its investigations, which have been focused on the multidisciplinary and systematic search of promising native plants and on introduced species such as ylang-ylang, palmarosa, turmeric, patchouli, mints, basils, citrus, geraniums, and others. Researchers from more than 10 universities have carried out their work in areas of botany and taxonomy, plant physiology, and ecology; on the study of secondary plant metabolites, crop and post-harvest improvement, EO distillation and its optimization, and design of rural stills; on the study of volatile fractions from plants and flowers, obtainment of extracts with solvents and supercritical fluids (SFE-CO2), and catalytic transformation of EOs or their main components; and on the study of their diverse biological properties (antioxidant, antimicrobial, insecticidal, antiviral, and others).
