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Usage

Uses

Used in Pharmaceutical Industry:
Segetalin B is used as a pharmaceutical agent for its estrogen-like activity, which can be beneficial in treating conditions related to hormonal imbalances or deficiencies.
Used in Drug Delivery Systems:
Similar to gallotannin, segetalin B can be incorporated into drug delivery systems to enhance its therapeutic efficacy and bioavailability. This may involve the use of organic or metallic nanoparticles as carriers for targeted delivery to specific tissues or cells.

Pharmacology

Examples of naturally occurring bioactive cyclopeptides are Segetalins A and B，which were isolated from Vaccaria segetalis (Caryophyllacea) and were shown to have estrogen-like activity. The seeds of Vaccaria segetalis are used in Chinese folk medicine to activate blood flow, to promote milk secretion, and to treat amenorrhea and breast infections. That Segetalin A and Segetalin B have the Try-Ala-Gly-Val (WAGV) sequence in common indicates this is the biologically active part of the molecules. NMR studies indicate,however,that the orientation of the Val residue is different in the molecules.The effect of this amino acid on the activity of the compounds might not be very important.

Relevant academic research and scientific papers

Characterization of the Fast and Promiscuous Macrocyclase from Plant PCY1 Enables the Use of Simple Substrates

Cyclic ribosomally derived peptides possess diverse bioactivities and are currently of major interest in drug development. However, it can be chemically challenging to synthesize these molecules, hindering the diversification and testing of cyclic peptide leads. Enzymes used in vitro offer a solution to this; however peptide macrocyclization remains the bottleneck. PCY1, involved in the biosynthesis of plant orbitides, belongs to the class of prolyl oligopeptidases and natively displays substrate promiscuity. PCY1 is a promising candidate for in vitro utilization, but its substrates require an 11 to 16 residue C-terminal recognition tail. We have characterized PCY1 both kinetically and structurally with multiple substrate complexes revealing the molecular basis of recognition and catalysis. Using these insights, we have identified a three residue C-terminal extension that replaces the natural recognition tail permitting PCY1 to operate on synthetic substrates. We demonstrate that PCY1 can macrocyclize a variety of substrates with this short tail, including unnatural amino acids and nonamino acids, highlighting PCY1's potential in biocatalysis.

A comparison of pseudoproline substitution effects on cyclisation yield in the total syntheses of segetalins B and G

The total syntheses of the naturally occurring cyclic pentapeptides, segetalins B and G, using a traceless pseudoproline-mediated cyclization reaction is reported. The incorporation of a cysteine-derived gem-dimethyl pseudoproline [Cys(ΨMe,MePro)] residue in the linear precursors to induce a cisoid amide bond prior to the head-to-tail cyclization resulted in improved cyclization yields in both cases. Cysteine-derived pseudoproline residues lacking the gem-dimethyl substituents [Cys(ΨH,HPro)] were not as effective at inducing cisoid conformations of the amide bonds and resulted in lower cyclization yields with a concomitant increase in the formation of cyclodimers. The Cys(ΨMe,MePro) containing cyclic peptides were subject to deprotection and desulfurization to give the alanine containing natural products in high overall yields. In contrast, deprotection of cyclic peptides containing Cys(ΨH,HPro) residues upon treatment with trifluoroacetic acid removed other side chain-protecting groups but left the Cys(ΨH,HPro) residues intact.