The Research On Extraction And Application Of The Horseradish Essential Oil With Fungicidal And Insecticidal Activities

Plant essential oils are oily liquids and volatilizable under room temperature. Because of their strong bioactivity, essential oils have become research hotpoints of phytochemistry and pesticide science and medicine now. Some of them can repellent fumigant to the stored-product insect pests,fungi caused soil infring diseases and nematodes. They are hopeful to become substitute products of the present fumigant.. This research is focus on the extraction, isolation and identification of horseradish essential oil. Studies on the bioactivity and application of the effective essential oils also had been carried out. The main results are as follows:1. The precursors of horseradish essential oil are sulfurglucosides. The optimum condition for extraction ITCs oil from horseradish was determined through L₁6(4)⁴ orthogonal experiments. Most ITCs oil can be acquired when one gram horseradish added with 20 mg tertiary butylhydroquinone, hydrolyzed at 65℃and pH 4.0 for 120 mins then extracted with CH₂Cl₂.2. GC and GC-MS analysis showed that allyl isothiocyanate (AITC)is the primary active ingredient in the horseradish essential oil.3. The rapid quantitative analysis methods were established through ultraviolet spectrophotometry and gas Chromatography(GC) in this paper. GC is suitable to determinate AITC contents in extraction concentrated solution of wet distillation. for more rapid and accurate. Its best chromatograph conditions are as follows: GC-9A, OV-1701 (DB-17, 30m^*0.32mm^*0.5μm), injector temperature 250℃, column temperature 60℃, detector temperature 250℃, lml/min N₂ (Carrier gas), 29ml/min compensates gas, 300 ml/min Air, 30 ml/min H₂, Divergence Ratio 1: 20, Input volume: 1μ1.4. The AITC (The active ingredient of horseradish essential oil) bioassay. When the AITC density is up to 3μg/mL, the fumigation effeciencies to Sitophilus zeamais Motschulsky, Rhizopertha dominica Fabricius, Tribolium ferrugineum Fabricius, LiposceIis entomophila Enderlein approach 100%. At 3.32μg/mL, AITC inhibited above 99% growth of 4 kinds fungi caused soil infringe diseases, When the AITC density is 1.43μg/mL, growth of other 8 kinds of fungi caused non-soil Infringe diseases were inhibited above 95.0%.5. The pot trials of AITC control on tomato root-knot nematode showed that the AITC lethal center quantity is 164.9μl per kilogram soil. When AITC density is 5μg/mL, the control efficiency is about 80% against the cotton desease caused by Colletotrichum gossyoii Southw, Fusarium moniliforme,Fusariumoxysporum f. vasinfecium in pot trial.6. The AITC residue and degrade had been analized on rice, rice seed, wheat seed, red jujube, Auricularia auricular and tobacco after fumigating processing. The result showed that, within the experiment density scope, the AITC had a lower residues and sooner degradation on red jujube, rice, Auricularia auricula. The residues are far lower than the AITC safety allowable scope. So the red jujube, rice, Auricularia auricular fumigated with AITC is safe and edible. To the seeds with rough surface, like the rice and tobacco seeds, AITC residue are high. This mean that the persistence is long. Also good for seed's long-term preservation.7. There is a top dosage limit for AITC to fumigate different crop seeds. When AITC density upto 10μg/mL, there is no obvious effect on the germination percentage of cotton, Mung bean, soybean and pea seeds. 10 days after the gumigation, the cucumber and watermelon seeds can normally germinate. But even half month past the fumigation, germination percentage of the rice seeds, barnyard grass seeds and corn seeds are very low.