Discovery of bioactive compounds
Interest in bioactive compounds obtainable from natural sources, mainly various plant organs, mammalian milk, eggs, meat, and fish, but also microalgae, macroalgae, and bacteria, has increased considerably in recent years. The attention paid to bioactive compounds is confirmed by the large amount of literature published in this field, and also by the several calls for the identification and recovery of valuable bioactives from renewable resources within the European Union Horizon 2020 program.
Compounds with biological activity are either peptides or small molecules, in particular phenolics. Bioactive peptides are very heterogeneous protein fragments, usually containing up to 20 amino acids, with some beneficial activity for human health. Sometimes these peptides are endogenous in the matrix, but more often to become active they need to be released from the parent protein by hydrolysis or some food processing (ripening, fermentation, cooking). The most common functions exerted by bioactive peptides include antioxidant, antimicrobial, anti-inflammatory and angiotensin-converting enzyme inhibitor activities, as well as antiproliferative, antimutagenic, anticancer, antithrombotic, and hypocholesterolemic activities.
Among nonpeptide bioactive molecules, there are many plant metabolites, such as phenolics (e.g., flavonoids, anthocyanins, phenolic acids, curcuminoids, other polyphenols), alkaloids, carbohydrates, carotenoids, fat-soluble vitamins, phytosterols, polyunsaturated lipids, and organosulfur compounds. The most frequently reported properties of these compounds are antioxidant, anti-inflammatory, antibacterial, and immunomodulatory activities; indeed, they could help to prevent diseases, including cancer, cardiovascular illness, neuronal degenerative diseases, and diabetes.
With bioactives, attention is often devoted mostly to assess the activity of the fraction where these compounds were isolated, whereas the identification and validation of both the structure (mainly achievable by mass spectrometry techniques) and the bioactivity of the single compound is neglected.
For these reasons, we wished to produce a topical collection focused on the critical analytical points in discovering new bioactive compounds (i.e., their separation, identification, and bioactivity assessment and validation). We think we have reached our goal, collecting four critical reviews and 12 research articles.
We would like to thank all authors for their high-quality contributions to this topical collection. We would also like to acknowledge the reviewers for their accurate and constructive criticisms. Finally, we would like to thank the Editorial Office and editors of Analytical and Bioanalytical Chemistry for their valuable cooperation and support.
We hope that this topical collection will provide an analytical prospective and useful support for researchers working in the field of bioactive compounds.