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Six new 14-membered ring cyclopeptide alkaloids, cambodines A–F (1–6), and two known compounds, frangufoline (7) and lotusanine B (8), were isolated from the root bark extract of Ziziphus cambodiana Pierre. Their structures and configurations were established based on 1D and 2D NMR, HRMS, ECD, and X-ray crystallographic data. Compounds 1 and 3 are rare 5(14)-type cyclopeptide alkaloids that possess an imidazolidin-4-one ring in the terminal unit. The cyclopeptides were tested for their in vitro antiplasmodial, antitubercular, and cytotoxic effects against three cancer cell lines. Compound 3 showed significant antiplasmodial activity against the malarial parasite Plasmodium falciparum, with an IC50 value of 6.09 μM.

Sanjoinine A ( 1 ) was synthesized from a 14-membered cyclopeptide prepared from a Garner aldehyde derived from d -serine. The key steps in the synthesis were the catalytic asymmetric reduction of ketone 2(b) and the final removal of the Boc group.

From seeds of Zizyphus vulgaris var. spinosus a new cyclic peptide, sanjoinenine, four new peptide alkaloids (sanjoinine-B, -D, -F and -G2), together with the known cyclic peptide alkaloids, frangufoline and amphibine-D have been isolated. The structures of the compounds were established by chemical and spectral methods.

Sanjoinine A ( 1 ) was synthesized from a 14-membered cyclopeptide prepared from a Garner aldehyde derived from d -serine. The key steps in the synthesis were the catalytic asymmetric reduction of ketone 2(b) and the final removal of the Boc group.

The ionophore activity of frangufoline(1), a sedative cyclopeptide alkaloid isolated fromZizyphus jujuba, was investigated by UV and CD spectroscopic methods. Frangufoline(1) showed ion binding activity to calcium and magnesium ions.

The minor alkaloids of Discaria longispina have been shown to be the known compounds adouetine Y' and frangufoline. Scutianine B and the new alkalo

Aus Blattern von Melochia pyramidata L. (Sterculiaceae) wurden neben den bereits fruher beschriebenen Substanzen Melochinin (1) und Cholin-chlorid die Verbindungen Melochinon (2), das D-Glucosid des Melochinins (3), 1-Methyluracil (4), Frangufolin (6), Adouetin Z (8) und Integerrenin (7) isoliert. Adouetin Z ist kein einheitliches Produkt, wie ursprunglich angenommen, sondern ein Gemisch von cis/trans-Isomeren. On Substances Isolated from Melochia pyramidata L. Besides the already earlier detected compounds melochinine (1) and cholin chloride the substances melochinone (2), the D-glucoside of melochinine (3), 1-methyluracil (4), frangufoline (6), adouetine Z (8), and integerrenine (7) were isolated from the leaves of Melochia pyramidata L. (Sterculiaceae). Adouetine Z is not a single compound as originally assumed but a mixture of cis/trans isomeres.

Sedative principles of the seeds ofZizyphus vulgaris var.spinosus have been characterized as sanjoinine-A (frangufoline), nuciferine and their congeners. Also, heattreatment of sanjoinine-A produced a more active artifact, sanjoinine-Ahl, which provides a scientific basis for heat-processing (roasting) of this Oriental medicine.

Frangufoline (sanjoinine-A)1) (1) was transformed into its epimer, sanjoinine-Ah1(2), on heat treatment. Absolute configuration of (1) and (2) was determined.

14-Membered cyclopeptide alkaloids, franganine, frangufoline, amphibine-D and mauritine-A has been isolated from the whole plant ot Zizyphus xylopyra and their structures established by spectral evidences. This Is the first report of these alkaloids from Z. xylopyra.

The isolation of cyclopeptide alkaloids, frangufoline from Zizyphus jujuba and Z. nummularia , amphibine-H and nummularine-K from Z. xylopyra and nummularine-R, a new 13-membered cyclopeptide alkaloid, from Z. nummularia is reported. The structure of the new alkaloid was elucidated by spectroscopic methods and by chemical degradation.