BIOCHEMICAL CHARACTERIZATION OF STEVIA ESSENTIAL OIL THROUGH DIFFERENT DRYING METHODS AND SOLVENTS

Abstract

Essential extracts from plants have been used as a food and medicinal cure since ancient times. Some plants have a good portion of carbohydrates e.g., stevia is being used as an excellent alternative to synthetic compounds i.e., sugar. Therefore, it is important to chemically characterize these nutrients and study their various biological properties. This research aimed to extract essential oil from stevia plant by using Soxhlet apparatus and analysis of nutrients present in the oil were performed by high performance liquid chromatography system i.e., HPLC. Two extraction solvents i.e., hexane (60/40; v/v) and ethanol (70/30; v/v) were used to compare the concentration of bioactive compounds. The plant material was subjected to two drying methods i.e., air dry and oven dry. 10 major compounds were identified as a result of the chemical characterization, in which steviol bioside i.e., 317.01615 (m/z) and stevioside (803.2189 m/z) that is obtained from oven drying using ethanol as extraction solvent were slightly greater than steviol bioside i.e., 315.2183 (m/z) and stevioside i.e., 802.8531 (m/z) obtained from oven drying using hexane as extraction solvent. Likewise, plant material subjected to air dry with ethanol as extraction solvent resulted in greater yield of steviol bioside i.e., 317.0717 (m/z) and stevioside i.e., 803. 3179 (m/z) as compared to steviol bioside i.e., 315.1104 (m/z) and stevioside (802.3185 m/z) that is obtained by air dry using hexane as a solvent. While using fresh leaves the concentrations of compounds i.e., stevioside (799.2187 m/z), dulcoside A (787.3759 m/z) and steviol (639.4189 m/z) obtained by using ethanol were greater than concentration of compounds obtained by hexane. While Rebaudioside A (965.3213 m/z), Rebaudioside B (803.3717 m/z), Rebaudioside C (940.4276 m/z), Rebaudioside D (1066.4763 m/z), Rebaudioside E (964.4273 m/z) and Rebaudioside F (789.3857 m/z) obtained by using hexane as extraction solvent were greater as compared to concentration of compounds obtained by using ethanol.  Based on these results, we can suggest that Stevia rebaudiana Bertoni can be a natural source of antioxidant, anti-inflammation and antimicrobial properties. It can also be considerd as a potential source of essential oil. These results suggest that the leaves of S. rebaudiana Bertoni can serve as therapeutic agents or in prevention of certain inflammatory diseases through their radical-scavenging capacities.