Yield and chemical composition of Hesperozygis ringens (Benth.) Epling essential oil cultivated in different areas.

The essential oil (EO) of Hesperozygis ringens (Benth.) Epling, which has several proven properties, is comprised mainly of monoterpenes and sesquiterpenes, and pulegone is the major compound. However, this is an endemic and endangered species. The aim of this study is to evaluate the viability of cultivating Hesperozygis ringens in different regions of Rio Grande do Sul and in a greenhouse. Seedlings obtained by using cuttings were transferred and cultivated for a year at each site. Then, leaves were collected and underwent EO extraction through steam distillation. During the same period, EO was also obtained from the natural population from which the cuttings were obtained. The chemical composition of EO samples in triplicates from each cultivation site and from the natural population were characterized in GC-MS. EO yield (%) was obtained by the ratio between leaf biomass (g) and EO mass (g) and it showed differences between areas; the yield obtained in the natural population was higher (3.14%) than the yield obtained in the cultivated areas (1.29%) and in the greenhouse (0.86%). The chemical compounds had low variation between areas, and most of them were oxygenated monoterpenes (74.82%). The commercial exploitation of H. ringens in different regions is feasible, as the plants tolerated climatic and edaphic conditions that were different from the ones of its natural occurrence area, and their EO yield remained high. The exception was the greenhouse, with lower yield yet with higher pulegone concentration. Furthermore, EO maintained its compounds, with few changes in their concentration.