Polyketides alkaloids

Saponins, glucosinate, polyketide, alkaloids, protelytic enzyme papain, chymopapain, flavonols. 

Polyketide Alkaloid Phytotoxins Polyhydroxy Piperidine Alkaloids References... 

Polyketides occuring in plants are not always exclusively synthesized from acetate units, but often are of mixed biosynthetic origin. Phenylpropanoid or terpenoid building blocks or sometimes both can be connected with the acetate-derived backbone. In addition, parts of the carbon skeleton can be derived from fatty acids or amino acids. This mixed assembly principle results in a plethora of structurally diverse compounds. Polyketide alkaloids obtained when nitrogen or nitrogen-containing precursors are incorporated into the polyketide backbone will also be discussed. 

There is no rigid scheme for classifying natural products—their immense diversity in structure, function, and biosynthesis is too great to allow them to fit neatly into a few simple categories. In practice, however, workers in the field often speak of five main classes of natural products terpenoids and steroids, fatty acid-derived substances and polyketides, alkaloids, nonribosomal polypeptides, and enzyme cofactors. 

In 2009 in a study of metabolites from Okinawan marine sponges, Kobayashi and coworkers [96] isolated and characterized a novel piperidine-containing polyketide alkaloid, plakoridine C from a sponge of the genus Plakortis sp. The authors noted that several pairs of resonances in the and NMR spectra were observed with a ratio of approximately 1 1 suggesting an epimeric or isomeric mixture of structures. The mixture was inseparable by semipreparative HPLC so the authors characterized the sample as the mixture. A HMQC spectrum showed the... 

Work by Konig et al. [97] led to the elucidation of two unusual polyketide alkaloids, cereolactam (115) and cereoaldomine (116), from the marine... 

Sorbicillamine A—A Polyketide Alkaloid Isolated from the Deep-Sea-Derived Fungus Penicillium sp. F23-3... 

---