Cassane Diterpenoids from the Aerial Parts of Caesalpinia
pulcherrima and Their Antifeedant and
Insecticidal Activities against Mythimna separate and Plutella xylostella
posted on 2020-03-30, 14:26authored byChun-Huan Li, Jia-Yao Zhang, Thi Mai Luong Tuong, Yao Liu, Xuan Nien Hoang, Jin-Ming Gao
Ten new cassane diterpenoids,
caesalpulcherrins A–J (1–10), together with 11 known analogues (11–21) were isolated from the aerial parts of Caesalpinia pulcherrima. Their structures and relative
stereochemistry were elucidated by spectrometric and spectroscopic
methods, including one-dimensional (1D) and two-dimensional (2D) NMR,
high-resolution electrospray ionization mass spectrometry (HRESIMS),
and single-crystal X-ray diffraction analysis. Compounds 1–4 represent the first examples of 2,5-dimethoxyfuranocassane
diterpenoids. Results of the antifeedant activity indicated that isovouacapenol
C (12) and pulcherrin N (14) exhibited remarkable
antifeedant activity against Mythimna separate with EC50 values of 3.43 and 4.20 μg/cm2, respectively. Meanwhile, pulcherrimin C (13) and 12-demethyl
neocaesalpin F (18) exerted significant antifeedant activity
against Plutella xylostella with an
EC50 data of 4.00 and 3.05 μg/cm2, respectively.
Some of the compounds showed obvious toxic activity against the plant-feeding
generalist insect herbivores, M. separate and P. xylostella, at 0.8 mg/mL (800
ppm). Furthermore, the structure–activity relationships of
antifeedant and insecticidal activities are also discussed in the
article.