RESUMEN
On-line method, which combines HPLC distribution and post-column reaction, was designed for the search of individual antioxidants. Optimization of the assay was performed evaluating optimal ABTS(+) radical cation concentration in the reactor, reaction time, impact of flow rate, reaction coil length. HPLC-ABTS assay validation in this work was performed by assessing reference antioxidant negative peak areas in radical scavenging chromatogram. Sample free radical scavenging activity is expressed as trolox equivalent antioxidant capacity (TEAC). Optimized and validated method was applied in detection of compounds possessing free radical scavenging ability in complex mixtures. Antioxidant compounds were studied in perilla (Perilla frutescens (L.) Britton var. crispa f. viridis) herbal raw material and its preparations. The HPLC-separated antioxidant compounds were identified using HPLC-photodiode array coupled to mass spectrometer, using a reference mass for determining accurate masses. Radical scavenging characteristics of rosmarinic acid, which is the dominant phenolic compound in medicinal herbal raw material of perilla and its preparations, were confirmed by the calculated TEAC values. Compounds responsible for antioxidant effect in herbal raw materials and herbal preparations were identified, evaluated and compared.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Depuradores de Radicales Libres/análisis , Extractos Vegetales/química , Preparaciones de Plantas/química , Ácidos Sulfónicos/química , Tiazoles/química , Benzotiazoles , Flavonoides/análisis , Flavonoides/aislamiento & purificación , Depuradores de Radicales Libres/aislamiento & purificación , Modelos Lineales , Perilla frutescens/química , Fenoles/análisis , Fenoles/aislamiento & purificación , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
This study represents the investigation of the essential oil of Perilla frutescens (L.) Britton, Perilla frutescens (L.) Britton var. crispa f. viridis, Perilla ocymoides L. var. bicolorlaciniata leaves collected at full flowering stage in August 2007, in Lithuania. As biogenesis and composition of essential oil depends on geographical location, environmental factors, plants with same chemotypes but growing in different conditions have different composition of major components. Plants have been cultivated in the collection of medicinal plants at Kaunas Botanical Garden of Vytautas Magnus University in Lithuania. Essential oil was analyzed using gas chromatography methods with flame ionization and mass spectrometry detectors. Thirteen constituents of essential oil, representing 96.42% of identified compounds, were indentified in the essential oil of Perilla frutescens (L.) Britton. Essential oil was ascertained to perillaketone chemotype. Principal compounds were found to be perillaketone and egomaketone. In Perilla ocymoides L. var. bicolorlaciniata aerial parts 97.70% of essential oil components were indentified with abundant amounts of perillaldehyde (72.07%) and limonene (13.15%). Essential oil contained two phenylpropanoids elemicin (1.91%) and myristicin (1.41%). In the essential oil of Perilla frutescens (L.) Britton var. crispa f. viridis 83.18% compounds were indentified. Principal compounds were found to be perillaldehyde (49.47%), limonene (11.76%), limonene oxides (9.85%) and caryophyllene oxide (7.21%). beta-Caryophyllene and perillaldehyde were the only compounds identified in all investigated perilla plants. Considering a broad diversity of Perilla L. species and chemotypes, it is important to discriminate cultivated Perilla L. species with identified chemotypes.
