Primary Study On Bioactivities Of Helianthemum Ordosicum Extracts

In this paper some kinds of crude extracts were produced in the way of cold-soaked process and Chinese traditional water-decoctum from Helianthemum ordosicum endemic to China. Different concentrations of these extracts were made to examine their bioactivities on many kinds of vegetable insect pests, plant pathogens and pine wood nematode. We chose the most effective two extracts and tested the bioactivities of their primary total alkaloids against Bursaphelenchus xylophilus. The results are as follows:1. The bioactivities of methanol extract, ethyl acetate extract, acetone extract, methylene dichloride extract, petroleum ether extract and water extract on 9 plant pathogenic fungi were examined by growth rate method in laboratory. Results showed that, different extracts had widely different effect on the fungi tested when the mass-concentration of Helianthemum ordosicum Maxim extracts was 100 g·L^-1 and the antifungal activity of the same extract also varied. But generally, the extracts contain secondary metabolism products of higher antifungal activity. The ethyl acetate extract and water extract had the highest antifungal activity. The results of the antifungal activities of different concentrations of ethyl acetate extract against 4 fungi showed the ethyl acetate extract had the strongest effect on Verticillium dahliae Kleb. V_43-1 and the minimum inhibitory concentration was 5g/L.2. The oviposition deterrence, ovicidal actions, antifeedant effect, stomach poisonous action, effects on the larval growth and development, and contact toxicity of acetone extract against Pieris rapae L were tested. The results showed the acetone extract had a certain oviposition deterrent effect, but the function decreased as time increased. It had certain inhibit function on egg hatching, no antifeedant effect on larva, no effects on the larval growth and development, and no significant stomach poisonous action or contact toxicity when the concentration was 10g/L. Besides it showed ovicidal actions but no activity against larva. The oviposition deterrence, ovicidal actions, antifeedant effect, stomach poisonous action, effects on the larval growth and development, and contact toxicity of acetone extract against Bursaphelenchus xylophilus were tested. The results showed the petrol extract had no insecticidal activities. As the increase of the polarity of extract solvent, the insecticidal activities of extract are increased.Ethanol extract and the water soluble components had the highest bioactivity.3. Different concentration of extracts of Helianthemum ordosicum were selected for bioassay of action on Bursaphelenchus xylophilus by the method of immersion. The extracts of higher polarity solutions (water, methanol, ethanol, methylene dichloride) showed higher nematicidal activities, but the activities of the petroleum ether extract and acetone extract were weaker. The results indicated that the active component was mostly distributed in this specific range of polarity and the water soluble components had the highest bioactivity.4. The primary total alkaloids of the most bioactive extracts—water and ethanol extracts, were extracted for bioassay of nematicidal action on Bursaphelenchus xylophilus. The results showed, the alkaloids from ethanol extract had very weak nematicidal action during 5 days, its corrected mortality was below 30% and the mortality had no significant difference from corrected mortality. That showed that the nematicidal action of total alkaloids was weaker than that of ethanol extract; The nematicidal activity of total alkaloids from water extract was higher at 6g/L than at 1g/L. Nearly no activity was shown when the concentration was 1g/L. From the 3rd day, the corrected mortalities were all below 70% which was weaker than water extract.