Studies On Chemical Constituents And Bioactivities Of Cynanchum Komarovii

On the basis of screening on bioactivities of Cynanchum komarovii including insecticidal, acaricidal, fungicidal and herbicidal bioactivity, the studies on herbicidal constituets of C. komarovii have been carried out. The main results are as follows. Petrolem ether extract, ether acetate extract, methanol extract, alkaloids and non-alkaloids of C. komarovii were tested against insecticidal and acaricidal activity. The results indicated that all test samples had no contact poison and stomach poison activity against 3rd instar larvae of Mythimna separate Walker at the concentration of 5% and also no evident poison-killed activity against imago of Tetranychus truncates Ehara at the concentration of 2000 mg·L-1.By means of mycelium growth rate, the all test samples of C. komarovii had different degree fungicidal activity against Botrytis cirerea, Alternaria solani, Alternaria alternate, Glomerella cingulata, F.oxysporium f.sp niveum, Bipolarissorokiniana shoem, Fusarium oxysporium and Exserohilum turcicum at the concentration of 500 mg·L-1. In addition, the results also showed that alkloids had the most intensive fungicidal activity and inhibiting rates of akloids against the eight fungi were all above 85.6%.Taking Digitaria sanguinalis (L.) Scop., Amaranthus retroflexus L., Brassica campestris and Triticum aestivum as test plants, the herbicidal activity of the five test samples of C. komarovii was tested at the concentration of 50 mg·L-1. The results of room test indicated that alkloids exhibited the highest inhibiting activity against the four test plants and had 100% inhibiting rates especial against germination, taproot, caulis of Amaranthus retroflexus L.. The results of pot test also showed that at the concentration of 200 mg·L-1 alkaloids had no inhibition against germination of Digitaria sanguinalis (L.) Scop., Amaranthus retroflexus L. and Brassica campestris in soil treatment. In treatment of stem and leaf of plant at the same concentration protective efficacies of alkaloids were 93.3% and 100% against Digitaria sanguinalis (L.) Scop. and Amaranthus retroflexus and the inhibiting rate of alkaloids was 43.1% against caulis of Brassica campestris, however, alkaloids had no inhibition against taproot of Brassica campestris.The herbicidal compound NW1 and NW2 were obtained from alkaloids with bioactivity-traced method. By means of spectroscopy methods such as FAB-MS, 1H NMR , 13C NMR and DEPT, compound NW1 and NW2 were identified as 7-demethoxylophorine and 6-hydroxy-2,3-dimethoxy phenanthroindolizidine. The results indicated that the values of EC50 of compound NW1 were 0.029 mg·L-1, 0.019 mg·L-1 and 0.025 mg·L-1 against germination, taproot, caulis of Amaranthus retroflexus L. and the values of EC50 of compound NW2 were 0.058 mg·L-1, 0.044 mg·L-1 and 0.037 mg·L-1 against germination, taproot, caulis of Amaranthus retroflexus L. respectively.