New myrsinol diterpenes from Euphorbia prolifera and their inhibitory activities on LPS-induced NO production

Isolation and Characterization of Sesquiterpenes from Celastrus orbiculatus and Their Antifungal Activities against Phytopathogenic Fungi

“…5−10 The same acyl groups as those appearing in compounds 1−3 were apparent, which were deduced and determined as one acetyl and two benzoyl groups according to its 13 C and 1 H NMR spectra. 19,23 The residual substituent groups could only be hydroxy groups, which were validated by the HR-ESIMS data. Through the same 2D NMR experiments, especially HMBC and 1 H− 1 H COSY experiments, as for compounds 1−3, the positions of the substituent groups (one acetoxy and two benzoyloxy groups) of 4 were determined, which suggested that the two benzoyloxy groups were attached at C-2 and C-8, the two hydroxy groups were ascribed to C-1 and C-9, and the acetoxy group was at C-6, respectively.…”

Structurally diversified diterpenoids from Euphorbia dracunculoides

“…All of the above evidences suggested that 7 shared a cyclomyrsinane-type diterpene skeleton, based on the cyclomyrsinane diterpenes reported from the genus Euphorbia. 12,14,[28][29][30] Five acyl groups including one benzoyl and four acetyl groups were also unambiguous in the 1D NMR spectra of 7. Further 2D NMR experiments ( , and , respectively, demonstrated the presence of three acetoxy groups and one benzoyloxy group at C-3, C-5, C-14 and C-8, respectively.…”

“…These assignments were in accordance with the configurations of reported cyclomyrsinane diterpenes. 12,14,28,29 Moreover, as shown in Fig. 4, a single-crystal X-ray crystallographic analysis using Mo Kα radiation was carried out to confirm the above assignments and the relative configuration.…”

“…In this study, euphordraculoins A-F were rare lathyrane glycosides with the sugar moiety attached to C-17, of which carbon have not been reported to be glycosylated. Considering that the absolute configurations of diterpenoids containing the characteristic gemdimethylcyclopropane unit from the genus Euphorbia have been determined, 4,29,37 the absolute structures of 1−19 were tentatively assigned as shown in Figure 1. Additionally, all the compounds were tested for cytotoxic activity against selected cancer cells.…”

“…All of the above data confirmed 10 as a premyrsinane esters. 13,[28][29][30][31] were conducted to assure the accurate structure of 10. The HMBC correlations of the proton signals at δ H 5.…”