Application of response surface methodology to extract yields from stinging nettle under supercritical ethanol conditions

Recovery of biologically active compounds from stinging nettle leaves part I: Supercritical carbon dioxide extraction

Stinging nettle is annual plant from Urticaceae family used as food and medicine. Due to the nonsufficient data, this work aimed to isolate the bioactive compounds from the stinging nettle leaves by supercritical carbon dioxide. Extracts were analyzed and assessed for antioxidant and cytotoxic activities. Main fatty acids were α-linolenic (31.06-58.42 mg/g E), palmitic (9.17-13.12 mg/g E), and linoleic (10.93-16.51 mg/g E) acids. Chlorophylls (33.00-7365.11 mg/100 g E) and carotenoids (166.88-722.62 mg/100 g E) were also found in all samples. Four empirical kinetic equations were effectively utilized for kinetic modeling of supercritical fluid extraction. As per proper statistical features, empirical models show good concurrence with experimental data. The numerical modeling of a process is gainful to foresee the process conduct and furthermore extend the methodology from laboratory to industrial scales. The principal component analysis was used to visualize the fatty acids profile, antioxidant capacity, and cytotoxic activity of extract.

Effect of high hydrostatic pressure extraction on biological activities of stinging nettle extracts

Ethanolic extracts obtained at 200 MPa presented higher phenolic compound concentration and better results concerning all biological activities and also showed potential for DNA protection with no pro-oxidant activity and no cytotoxicity.

Optimization of the processing technology of Fructus Arctii by response surface methodology

The present study was designed to optimize the processing of Fructus Arctii by response surface methodology (RSM). Based on single factor studies, a three-variable, three-level Box-Behnken design (BBD) was used to monitor the effects of independent variables, including processing temperature and time, on the dependent variables. Response surfaces and contour plots of the contents of total lignans, chlorogenic acid, arctiin, and arctigenin were obtained through ultraviolet and visible (UV-Vis) monitoring and high performance liquid chromatography (HPLC). Fructus Arctii should be processed under heating in a pot at 311 °C, medicine at 119 °C for 123s with flipping frequently. The experimental values under the optimized processing technology were consistent with the predicted values. In conclusion, RSM is an effective method to optimize the processing of traditional Chinese medicine (TCM).