Two new lathyrane type diterpenoids from Euphorbia aellenii

New macrocyclic diterpenes fromEuphorbia connataBoiss. with cytotoxic activities on human breast cancer cell lines

“…Other downfield-shifted protons were observed at d H 3.14 (br-s, H-12), 3.15 (overlapped, H-11), 3.07 (dd, J ¼ 11.2 and 3.6 Hz, H-4), 2.79 (dd, J ¼ 16.0 and 11.2 Hz, H-1b) and 2.52 (dd, J ¼ 16.0 and 9.6 Hz, H-1a), characteristic of myrsinane-type skeleton (Ahmad et al 2005 and H-11 to H-13, as well as HMBC correlations, resembled a jatrophane-type structure containing an olefinic bond and a ketonic group on the 12-membered ring. In addition, two HMBC correlated unusual upfield oxygenated carbons, one quaternary d C 59.8 (C-6) and one tertiary d C 56.9 (C-5), without HMBC correlations with ester carbonyls and lack of free hydroxyl absorptions in the IR spectrum, suggested the presence of an epoxide ring in the main jatrophane structure (Ayatollahi et al 2010). In the C NMR, signals at d C 83.2 (d, C-3), 70.1 (d, C-8), 77.3 (d, C-9) and 96.3 (s, C-15) represented ester-bearing carbons.…”

Improving the MDR reversal activity of 6,17-epoxylathyrane diterpenes

“…The known lathyranes 5a,15b-diacetoxy-3b-propanoyloxy-6(17)-epoxylathyr-12E-en-14-one (3), 5a,15b-diacetoxy-3b-butanoyloxy-6(17)-epoxylathyr-12E-en-14-one (4) and 5a,15b-diacetoxy-3b-benzoyloxy-6(17)-epoxylathyr-12E-en-14-one (5) 11 ( Fig. 1; referred as epoxyboetiranes K-L) were also isolated along with the tetracyclic triterpene cycloart-23-ene3b,25-diol (15) and the tigliane diterpene euphodendriane A (16) (Supplementary data). The known compounds were identified by comparison of their physical and spectroscopic data to those reported in the literature.…”

“…The above mentioned data indicated a 6(17)-epoxylathyr-12E-en-14-one diterpenic scaffold for 1. 11,14,15 Further structural details were obtained by two-dimensional NMR experiments (COSY, HMQC, and HMBC), which coupled with literature data, allowed unambiguous assignment of all carbon signals as well as the location of the acetyl groups at C-3, C-5 and C-15 (Supplementary data). The relative stereochemistry of 1 was deduced through the analysis of a NOESY spectrum, assuming a trans-ring fusion and an a orientation for H-4 (Supplementary data), and by comparison of the coupling constant values with those reported in the literature for similar diterpenes whose absolute stereochemistry was determined by X-ray analysis.…”

Unusual ingenoids from Euphorbia erythradenia Bioss. with pro-apoptotic effects

“…The aerial parts of E. erythradenia also afforded a new diterpene belonging to the myrsinane type diterpenes (5, Fig. 1 [11]. The presence of one propanoyl and one angeloyl group was also inferred by NMR signals [13].…”

“…Dried aerial parts of flowered plant were extracted with dichloromethane:acetone. After VLC on a cake of 20% paraffin impregnated silica-gel to remove waxes and pigments, fraction eluted with MeOH:H 2 O (6:4) was separated on silica gel CC and purified by HPLC on normal phase silica column to afford five new macrocyclic diterpenes (1)(2)(3)(4)(5) [11]. Singlet methyl proton δ H 2.13 s with HMBC cross links with esteric carbonyl carbon δ C 170.5 and loss of 60 m/z in the ESI-MS indicated presence of one acetate group [12].…”