Cyclopolypeptides are among the most predominant biomolecules in nature, especially those derived from plant seeds. This category of compounds has gained extraordinary attention due to remarkable variety of structures and valuable biofunctions. These congeners display enormous variation in terms of both structure and function and are the most significant biomolecules due to their widespread bioproperties. The estrogenic activity, immunosuppressive activity, cytotoxicity, vasorelaxant activity, and other properties possessed by cyclic peptides from seeds of plants make these congeners attractive leads for the drug discovery process. The current study covers the important structural features, structure-activity relationship, synthesis methods, and bioproperties of plant seeds-originated bioactive peptides from Vaccaria segetalis, Linum usitatissimum, and Goniothalamus leiocarpus, which may prove vital for the development of novel therapeutics based on a peptide skeleton.
Bridged peptide macrobicycles (BPMs) from natural resources belong to types of compounds that are not investigated fully in terms of their formation, pharmacological potential and stereo-chemical properties. This division of biologically active congeners with multiple circular rings, has merits over other varieties of peptide molecules. BPMs form one of the most hopeful grounds for establishment of drugs because of their close resemblance and biocompatibility to proteins, and these bio-actives are debated as feasible realistic tools in diverse biomedical applications. Despite huge potential, poor metabolic stability and cell permeability limit the therapeutic success of macrocyclic peptides. In this review, we have comprehensively explored major bicyclic peptides sourced from plants and mushrooms including βs-leucyl-tryptophano-histidine bridged and tryptophano-cysteine bridged peptide macrobicycles. The unique structural features, structure activity relationship, synthetic routes, bioproperties and therapeutic potential of the natural BPMs are also discussed.
Peptides are distinctive biomacromolecules that demonstrate potential cytotoxicity and diversified bioactivities against a variety of microorganisms including bacteria, mycobacteria, and fungi via their unique mechanisms of action. Among broad-ranging pharmacologically active peptides, natural marine-originated thiazole-based oligopeptides possess peculiar structural features along with a wide spectrum of exceptional and potent bioproperties. Because of their complex nature and size divergence, thiazole-based peptides (TBPs) bestow a pivotal chemical platform in drug discovery processes to generate competent scaffolds for regulating allosteric binding sites and peptide-peptide interactions. The present study dissertates on the natural reservoirs and exclusive structural components of marine-originated TBPs, with a special focus on their most pertinent pharmacological profiles, which may impart vital resources for the development of novel peptide-based therapeutic agents.