Enantioselective Separation Of 4,8-DHT And Bioactivity Test Of The Enantiomers On Various Plant Species

Based on our previous research, 4, 8-dihydroxy-1-tetralone(4, 8-DHT, Rac) as a new bioactive metabolite had the potential to become a natural herbicide. However, it is unclear to predicate the herbicide behavior of the enantiomers of(S)-(+) isosclerone and(R)-(-) regiolone. Chirality is influencing our life every second. A pair of enantiomers will react differently only in a chiral environment thus they initiate.Accordingly, on the background of known 4, 8-DHT become a candidate element of herbicide, we suppose a single enantiomorphism isomers with same herbicidal activity, and the same time, we developed high-performance liquid chromatography(HPLC) method for resloution of Rac and preparative HPLC method for enantioseparation of Rac, on the basic of enantioseparation, we employed detection techniques to analysis the effect of apparent biological characteristics of seed germination and seedling growth and antioxidant enzymes(SOD, CAT, APX) activity and MDA content of five kinds of weed seeds(Amaranthus retroflexus, Eleusine indica, Paspalum natatu, Cyperus rotundus, Agrostis stolonifera) to validate assumption. The main results are as follows:A direct HPLC method for resloution of Rac by using coated cellulose tris(3,5-dimethylphenylcarbamate)(CDMPC)(Chiral OD-H(250 mm�4.6 mm,5 ?m))chiral stationary phase(CSP) had been developed. The satisfactory enantioseparation was performed by using the mobile phase consisted of a mixture of n-hexane and iso-propanol(95:5, v/v) containing 0.1% acetic acid(AcA) under a flow rate of0.8 mL�min-1 at 20 ? and detection wavelength at 330 nm.A preparative HPLC method for enantioseparation of Rac by using CDMPC(Chiral OD-H(250mm�20 mm, 5 ?m)) CSP had been developed. The satisfactory enantioseparation was performed by using the mobile phase consisted of a mixture of n-hexane and iso-propanol(90:10, v/v) under a flow rate of 12mL�min-1 at 20?and detection wavelength at 330 nm.The effect of Rac, S and R on the apparent biological characteristics, antioxidant enzymes and MDA content of five kinds of weed seeds were rate to structure and concentration. Among the physiological indexes of five kinds of weeds measured, the germination rate, radicle, plumule, fresh weight are sensitive to the change of concentration of Rac, R and S, the inhibition rates increase with rising concentration and the inhibition rates of S higer than Rac and R; The activities of SOD, CAT and APX associated with Rac?R and S concentration during seedling growth, in certain concentrations range, activity increased with increasing concentration of the Rac, R and S, after that, activity decreased with increasing concentration of the Rac, R and S. However, the content of MDA decreased with increasing concentration of the Rac, R and S, after that, MDA increased with increasing concentration of the Rac, R and S.