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Insecticidal and antifeedant effects of two alkaloids from C ynanchum komarovii against larvae of P lutella xylostella L
Author(s) -
Guo H.,
Yang M.,
Qi Q.
Publication year - 2014
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/jen.12075
Subject(s) - alkaloid , plutella , biology , instar , larva , bioassay , toxicity , botany , fractionation , toxicology , chemistry , chromatography , organic chemistry , genetics
Abstract A bioassay‐guided fractionation of C ynanchum komarovii crude alkaloid extract led to the isolation of two alkaloids. The isolated alkaloids were identified as 7‐demethoxytylophorine (1) and 6‐hydroxyl‐2,3‐dimethoxy phenanthroindolizidine (2) based on the comparison of their spectroscopic characteristics with the literature data. Insecticidal, antifeedant and growth inhibitory effects of these two alkaloids against the 3rd instar larvae of P lutella xylostella L . ( L epidoptera: P lutellidae) were examined. The results showed that alkaloid 1 was more toxic than alkaloid 2 against the 3rd instar larvae of Plutella xylostella L., but both alkaloids were less toxic than the total alkaloid fraction. For antifeedant activity, alkaloid 1 showed AFC 50 of 1.82 mg/ml at 24 h after treatment, alkaloid 2 showed 3.89 mg/ml, while total alkaloids showed 1.56 mg/ml. In dipping toxicity test, alkaloids 1 and 2 produced 93.3% and 63.3% mortality at 72 h after treatment, respectively, while total alkaloids produced 96.7% mortality. The LC 50 values for alkaloids 1, 2 and the total alkaloids were 3.54, 9.21 and 2.63 mg/ml, respectively. The development of larvae was also inhibited, and the growth inhibition rates at the concentration of 15.00 mg/ml were 92.8%, 78.2% and 98.6% for alkaloids 1, 2 and total alkaloids, respectively, at 72 h after treatment. Compared with antifeedant and dipping effect, the alkaloids 1, 2 and total alkaloid fraction revealed weak feeding toxicity, and their corrected mortality rates at the concentration of 15.00 mg/ml were 60.0%, 40.0% and 63.3% at 7 days after treatment. The LC 50 values for alkaloids 1, 2 and total alkaloids were 12.58, 32.37 and 8.88 mg/ml, respectively, at 7 days after treatment.