Antifeedant and Antiviral Diterpenoids from the Fresh Roots of Euphorbia jolkinii

Abstract

The perennial herbaceous plant Euphorbia jolkinii (Euphorbiaceae) is a noxious weed widely distributed in the grasslands of northwestern Yunnan and has greatly threatened the local biodiversity. Phytochemical investigation on the fresh roots of E. jolkinii afforded six new diterpenoids 1, 2, 4–6, and 8, together with fifteen known diterpenoids. Their structures were elucidated on the basis of 1D and 2D NMR and other spectroscopic methods. Casbane, lathyrane, abietane, and ent-kaurane diterpenoids were reported from this plant for the first time. Selected compounds were evaluated for their antifeedant and anti-RSV (respiratory syncytial virus) activities. Compound 2 and ingenol (3) exhibited moderate antifeedant activity against a generalist insect herbivore, Spodoptera exigua, with EC50 values of 17.88 and 17.71 μg/cm2 respectively. Compound 19 showed significant anti-RSV activity, with 50 % inhibition (IC50) value of 10.0 μM and selective index of 8.0. Compounds 1 and 2 were less active against RSV virus, both with IC50 value of 25 μM, and with selective indices of 1.0 and 3.2 respectively. These findings provided new evidence for the biological functions and utilization of the diversified diterpenoid metabolites in the roots of this rich but harmful plant.Graphical AbstractElectronic supplementary materialThe online version of this article (doi:10.1007/s13659-014-0009-3) contains supplementary material, which is available to authorized users.

Assessing Specialized Metabolite Diversity in the Cosmopolitan Plant Genus Euphorbia L.

“…Consistent with the low chemical diversity exhibited by subg. Chamaesyce and previous observations of Euphorbia diterpenoids exhibiting anti-herbivore biological activity (Batra, 1983; Hundsdoerfer et al, 2005a; Huang et al, 2014; Hua et al, 2017), we find very few to no Euphorbia diterpenoids in representatives of the American radiation of subg. Chamaesyce (Figure 1).…”

“…One strategy of defense invoked by plants to overcome their sessile habit is through local immunomodulatory and inflammatory effects on herbivores. Previous studies (Huang et al, 2014; Hua et al, 2017) have reported anti-feeding activity of selected Euphorbia diterpenoids against generalist plant-feeding insects, Spodoptera exigua (Hübner, 1808) and Helicoverpa armigera (Hübner, 1808). In vitro , Euphorbia diterpenoids are known to induce different immunomodulatory responses through the selective modulation of PKC including the release of prostaglandins and pro-inflammatory cytokines such as TNF-α, interleukin-6, and interleukin-1β (Smith and Meldrum, 1992; Berman, 2012; Uto et al, 2012; Jian et al, 2018; Zhang et al, 2019).…”

“…Chamaesyce (Figure 5 and Supplementary Figures S4, S10). Compartmentalization of the diterpenoids to mainly young stems and roots could suggest possible functions as anti-feeding molecules (McKey, 1979; Batra, 1983; Hundsdoerfer et al, 2005a; Huang et al, 2014; Hua et al, 2017).…”

“…The genus’ chemical diversity is characterized by an extraordinary diversity of macro- and polycyclic diterpenoids, biosynthetically derived from a head-to-tail cyclization of the tetraprenyl pyrophosphate precursor (Shi et al, 2008; Vasas and Hohmann, 2014; Appendino, 2016). These compounds are known to play an important ecological role as feeding deterrents and have shown exclusive occurrence and chemotaxonomic relevance in the plant families Euphorbiaceae and Thymelaeaceae (Batra, 1983; Hundsdoerfer et al, 2005a; Huang et al, 2014; Vasas and Hohmann, 2014; Hua et al, 2017). In vitro Euphorbia diterpenoids are known to induce different immunomodulatory responses through the selective modulation of protein kinase C (PKC) including the release of prostaglandins and pro-inflammatory cytokines such as TNF-α, interleukin-6, and interleukin-1β (Smith and Meldrum, 1992; Berman, 2012; Uto et al, 2012; Jian et al, 2018; Zhang et al, 2019).…”

Abietane Diterpernoids from the Roots of Euphorbia ebracteolata

“…Euphorbiaceae is one of the largest families of higher plants, comprising about 500 genera, 5000 species, and widely distributes in the world, especially in the tropical and subtropical regions [ 6 ]. The genus Euphorbia is the largest in the spurge family, some of which have been used as medicinal plants for a long time [ 7 , 8 ]. Among them, the roots of Euphorbia ebracteolata are used to treat pulmonary tuberculosis, chronic tracheitis, and psoriasis in Traditional Chinese Medicine (TCM) [ 9 ].…”