Optimization Of Ultrasonic-assisted Extraction And Herbicidal Activity Of The Crude Extracts From Chicory Root

Chicory (Cichorium intybus L.) belongs to the Asteraceae family and Asteraceae genera, a kind of plant with biennial or perennial, both be used as food and herb, introduced to China in the last 80s. Applied orthogonal design (L₁₆(4³Ã—2⁶)) to optimize the eight key factors that are ethanol content (v/v, %), solvent-to-solid ratio (v/w, ml/g), sonication temperature(℃), impregnation time (h), impregnation repetitions, sonication time (min), ultrasonic input power(W) and sonication repetitions on chicory roots with ultrasound-assisted extraction. Globally optimized the optimum extracting conditions of the eight factors and ordered the importance of them for influencing the extraction rate at altrasonic with a fixed frequency of 40 kHz. Base on the former results, monocotyledon of Echinochloa crusgalli (L.) Beauv and dicotyledon of Amaranthus retroflexus L. which were widespread weeds were elected as the objects studying the herbicidal activity of chicory root crude extracts, the seed germination index (GI), root length (RL) and shoot length (SL) of the two weeds have been determined respectively. Compared with the control group for analysis chicory root whether with the significant herbicidal activity, and calculated the half inhibited concentration of the chicory root crude extracts for each indexes of E. crusgalli (L.) and A. retroflexus L., besides, compared with 2, 4-D as the positive control group to judge the practical value of chicory root for killing weeds. Combined with the extracting process and the herbicidal effect to be explored chicory root was evaluated the potential as botanical herbicides and industrial utilization.The mainly results as following:1. Eight factors that were ethanol content, solvent-to-solid ratio, sonication temperature and so on were globally optimized, and the optimum condition were: ethanol content range from 50% to 75%, solvent-to-solid ratio at 24:1 to 32:1, sonication temperature at 50℃, impregnation 24h, impregnation two times, sonication time was 30 min, ultrasonic input power was 400W and sonication two times.2. According to the effect of the eight factors on the extraction rate of chicory root, the orders of them were displayed in decreasing sequence were the ethanol content, solvent-to-solid ratio, sonication temperature, impregnation time, impregnation repetitions, sonication time, ultrasonic input power and sonication repetitions.3. E. crusgalli (L.) and A. retroflexus L. were both significant inhibited after treated 16 different chicory root crude extracts, moreover, the inhibition depended on the concentration of the extracts, mostly for the two weeds had the equal effect comparing with the 2,4-D positive control group at the concentration of 40.5g/l. Except for the chicory root crude extracts with 100% ethanol solution, the promotion of each index for A. retroflexus L. more significant than E. crusgalli (L.) at smaller concentration.4. The half inhibited concentration of seed germination index, root length and shoot length of E. crusgalli (L.) and A. retroflexus L. were respectively calculated applying quadratic regression model. IC₅₀ of GI, RL and SL of E. crusgalli (L.) were 13.71g/l, 8.89g/l and 28.90g/l, respectively, while A. retroflexus L. were 11.79g/l, 11.61g/l and 39.90g/l, respectively. Besides, the experiment also calculated the corresponding concentration of chicory root crude extracts according the maximum / minimum of each index, seed germination index and root length of the two weeds about the inhibited concentrations were more practical, E. crusgalli (L.) about the concentration of crude extracts were 59.2g/l and 30.8g/l, respectively, and A. retroflexus L. were 33.7g/l and 32.7g/l, respectively.5. The inhibition effect of E. crusgalli (L.) better than A. retroflexus L. when combined with the extracting process and the herbicidal activity, on overall, E. crusgalli (L.) and A. retroflexus L. at early growth both were inhibited perfectly with chicory root, indicated chicory root had the potential as botanical herbicides, and enriched the useful resources of botanical herbicides.