J Pharm Pharmacogn Res 3(suppl. 1): S34, 2015
Proceedings of the 4th International Symposium on Pharmacology of Natural Products FAPRONATURA 2015 September 21st-25th, 2015; Cuban Society of Pharmacology. Topes de Collantes, Sancti Spiritus, Cuba.
OC-16: CYCLOPEPTIDE ALKALOIDS FROM Ziziphus oxyphylla
Tuenter E, Exarchou V, Ahmad R, Apers S, Hermans N, Pieters L.
Introduction: With about 40 species, the genus Ziziphus is one of the larger genera in the Rhamnaceae family. The plants, mostly spiny shrubs and small trees, grow in warm-temperate or subtropical climates. Traditionally Ziziphus plants are used to treat skin infections, fever, diabetes and many other pathological conditions, but the active compounds are often not known. A specific class of constituents which are typically found in this genus and which might be responsible for certain health benefits claimed in the traditional use are the cyclopeptide alkaloids (CPAs). For some the antimicrobial, antipyretic and/or anti-diabetic activity has already been shown, but only a few compounds were tested up to now. In this project the isolation of CPAs from Ziziphus oxyphylla Edgew. was performed. Material and Methods: A crude extract was prepared in 80% methanol from 2.9 kg of small dried roots, followed by liquid-liquid partitioning and fractionation by flash chromatography. After this, the isolation of pure compounds was done by means of semi-preparative HPLC-DAD-MS. For the structure, elucidation NMR spectroscopy was used, including 1H, 13C, COSY, HSQC and HMBC spectra. Results: Ten CPAs could be identified: the five known compounds hemsine-A (1), nummularine-R (2), oxyphylline-A (3), oxyphylline-C (4) and ramosine-A (5); Odesmethylnummularine-R (6), which contains a hydroxyl-group instead of a methoxy-group; and two oxidized compounds, i.e. hemsine-A-N-oxide (7) and O-desmethyl-nummularine-R-N-oxide (8). Furthermore two new cyclopeptide alkaloids were identified, which both contain cinnamic acid instead of an amino acid as the terminal moiety in the side chain. Given their structural resemblances with the already existing oxyphyllines A-D and the fact that the compounds are isolated from Z. oxyphylla, these compounds were named oxyphylline-E (9) and oxyphylline-F (10). Conclusions: To our knowledge, it is the first time these alkaloids are being reported. Further research is ongoing, more in particular the evaluation of their antimicrobial and/or anti-diabetic activities.
Citation Format: Tuenter E, Exarchou V, Ahmad R, Apers S, Hermans N, Pieters L (2015) Cyclopeptide alkaloids from Ziziphus oxyphylla. [Abstract]. In: Proceedings of the FAPRONATURA 2015; 2015 Sep 21-25; Topes de Collantes, Sancti Spiritus: CSF. J Pharm Pharmacogn Res 3(Suppl. 1): S34. Abstract nr OC-16.