Compounds Derived from Nature: From Chemical Diversity to Sustainable Applications

Nature remains one of the most productive sources of chemical diversity and a continuing inspiration for the design of synthetic analogs. Plants, fungi, algae, microorganisms, and other biological systems produce a wide variety of natural compounds, traditionally referred to as secondary metabolites and increasingly recognized as specialized metabolites, which mediate defense, communication, adaptation, and survival. These molecules include phenolics, alkaloids, terpenoids, carotenoids, flavonoids, lipids, peptides, polysaccharides, and numerous structurally unusual compounds. Their chemical diversity continues to support research in chemistry, biotechnology, food science, agriculture, medicine, cosmetics, environmental protection, and materials science.

This Special Issue of MDPI Compounds, “Compounds Derived from Nature,” was conceived to connect areas of natural-product research that are often considered separately: sustainable sourcing and recovery, chemical characterization, structure–activity relationships, biological evaluation, and application-oriented development. Its originality lies not only in the diversity of biological sources and compound classes represented but also in its integration of fundamental chemistry with technological and sustainability objectives. The collection therefore examines nature-derived compounds as components of interconnected scientific and production systems rather than solely as isolated molecules.

The central objective of this Special Issue is to demonstrate how natural compounds can advance both fundamental knowledge and practical innovation. Natural products have long served as sources of pharmaceuticals and lead structures for drug discovery, and recent reviews continue to emphasize their importance in modern medicine, particularly when combined with advanced analytical methods, genomics, synthetic biology, computational prediction, and improved screening strategies [1,2,3,4,5]. Their relevance now extends well beyond the pharmaceutical sector. Nature-derived compounds are being investigated for use in functional foods, nutraceuticals, sustainable agriculture, anti-aging and cosmetic formulations, antifouling and antimicrobial technologies, environmental protection, biomass valorization, and circular bioeconomy strategies [6,7,8].

The fifteen papers collected in this Special Issue can be considered within four interconnected scientific themes: green extraction and processing technologies; structure–activity relationships and biological evaluation; biomass valorization and the circular bioeconomy; and factors influencing the production and application of specialized metabolites. Several contributions bridge more than one of these areas, illustrating the interdisciplinary character of contemporary natural-product research. Together, they show that progress in this field depends on coordinating sustainable sourcing, efficient recovery, rigorous characterization, mechanistic evaluation, safety assessment, and application-driven formulation.

1. Green Extraction and Processing Technologies

The first theme concerns the development of efficient and environmentally responsible methods for recovering natural compounds. Conventional procedures remain important, but growing attention is being directed toward technologies that reduce solvent consumption, processing time, energy demand, and environmental impact. Green extraction principles emphasize safer solvents, process intensification, renewable resources, selectivity, and improved efficiency [9,10,11].

Within this context, the collection examines emerging technologies for recovering antioxidant compounds from edible and medicinal mushrooms, including ultrasound, microwave, pressurized liquid, supercritical fluid, enzyme-assisted, and pulsed electric field extraction methods [12]. Related contributions extend this perspective to ultrasound-assisted co-recovery of carbohydrates and proteins from macroalgae and to the processing of plant-derived oils and biopolymers. Considered together, these studies demonstrate that extraction is not merely a preliminary laboratory step. It is a central determinant of yield, composition, bioactivity, scalability, safety, and environmental performance.

A broader conclusion emerging from this theme is that no single recovery or extraction method is optimal for every biological matrix or class of compounds because method selection must account for matrix characteristics, target-analyte properties, and the required degree of separation and purification [13]. Future progress will require systematic comparison of processes using common criteria, including selectivity, compound stability, solvent and energy requirements, waste generation, cost, and compatibility with industrial scale-up. Greater integration of extraction design with downstream purification, formulation, and life-cycle assessment will also be necessary.

2. Structure–Activity Relationships and Biological Evaluation

The second theme links chemical structure and composition with biological function. Natural compounds frequently possess stereochemical complexity and functional-group diversity that are difficult to reproduce through conventional synthesis. These characteristics contribute to their biological activities and value as lead compounds [6,14,15,16]. At the same time, structural complexity presents challenges related to identification, standardization, chemical stability, reactivity, bioavailability, and mechanism-of-action studies.

The papers within this thematic group examine chemically distinct natural products and complex extracts in relation to antioxidant, antimicrobial, antifouling, anti-aging, anticancer, antiprotozoal, metabolic, and other biological effects. Comparative phytochemical studies of closely related plant species illustrate why taxonomic similarity cannot be assumed to imply chemical or functional equivalence. Investigations of plant extracts and seed oils further demonstrate the importance of relating metabolite and fatty-acid profiles to measurable biological outcomes. Studies of natural delivery systems and controlled-release formulations extend this relationship from compound identification to functional performance.

The review of endoperoxides provides a particularly clear example of the relationship between a distinctive structural motif and biological activity. Endoperoxides are highly oxygenated terpenoids characterized by cyclic peroxide groups that contribute to their chemical reactivity and pharmacological potential [5]. When considered alongside contributions addressing bioactive compounds from Allium, Capsicum, Cynara, Bombax, and Pseudobombax, this work highlights the need to combine natural-product chemistry with pharmacological evaluation, molecular docking, mechanistic experiments, and a critical assessment of the available evidence [6].

A recurring challenge across this group is the gap between preliminary in vitro activity and demonstrated efficacy in biologically relevant models. Future studies should therefore prioritize validated assays, appropriate controls, dose–response analysis, identification of active constituents, bioavailability, toxicity, and confirmation of predicted molecular mechanisms. Computational methods can accelerate hypothesis generation, but their conclusions require experimental verification.

3. Biomass Valorization and the Circular Bioeconomy

The third theme addresses the conversion of agricultural, marine, and food-processing residues into sources of functional compounds and value-added materials. The transition toward a sustainable bioeconomy requires biological residues to be regarded not simply as waste, but as chemically diverse resources [6,7]. This approach can reduce disposal burdens while generating ingredients and materials for food, cosmetic, pharmaceutical, and industrial applications.

Several contributions embody this principle by examining fruit seeds, pulp–seed mixtures, macroalgae, seed mucilage, and plant oils. Chaichit et al. investigated fractions obtained from Passiflora edulis by-products and evaluated their metabolite profiles, antioxidant properties, enzyme-inhibitory activities, and collagen-stimulatory potential [8]. Other studies explore discarded or underused seeds as sources of bioactive oils and natural biopolymers, and macroalgal biomass as a source of carbohydrates and proteins [13,14,15,16,17]. Research on the functionalization of plant oils further shows how renewable feedstocks can be transformed into materials with tailored performance characteristics.

These contributions expand the concept of valorization beyond the recovery of individual high-value molecules. They support integrated use of biological feedstocks, in which multiple fractions may be directed toward complementary applications. The resulting scientific challenge is to preserve biological activity and material functionality while maintaining economic feasibility, consistent quality, and a demonstrable environmental advantage over conventional alternatives.

Future research in this area should incorporate techno-economic analysis, material-flow evaluation, and life-cycle assessment at an earlier stage. The designation of a process as “green” or “circular” should be supported by evidence concerning resource consumption, solvent recovery, energy use, by-product generation, and end-of-life considerations. Collaboration among chemists, process engineers, materials scientists, and industrial partners will be essential for translating laboratory-scale valorization into viable production systems.

4. Factors Influencing Specialized Metabolite Production

The fourth theme concerns the biological and environmental regulation of specialized metabolites. Their biosynthesis is influenced by genotype, developmental stage, environmental conditions, biotic and abiotic stress, cultivation practices, harvesting time, and post-harvest processing and storage [18,19,20,21]. These variables help explain why chemically similar biological materials may yield extracts with different compositions and activities.

The contributions related to pungent Capsicum species, sesquiterpene lactones in Cynara, and the phytochemical variability of medicinal plants demonstrate that chemical composition is dynamic rather than fixed. This has direct implications for reproducibility, agricultural production, biological evaluation, and product standardization. Understanding how specialized metabolite profiles respond to cultivation and processing conditions can inform strategies to enhance desirable compounds in crops, superfruits, herbs, spices, and other high-value plants [20,22].

Research in this area increasingly combines controlled cultivation, metabolomics, molecular biology, and data-driven approaches. Future work should seek to distinguish genetic effects from environmental influences, establish standardized reporting of plant and growth conditions, and identify reliable chemical markers of quality. Such information is essential for moving from promising laboratory observations to reproducible raw materials and transferable technologies.

5. Overarching Scientific Message and Future Perspectives

The overarching message of “Compounds Derived from Nature” is that chemical diversity alone is not sufficient to ensure scientific or practical value. A promising natural compound or extract must also be sourced responsibly, recovered efficiently, rigorously characterized, evaluated using biologically meaningful methods, and formulated for a defined application. The strongest contributions in the field are therefore those that connect multiple stages of this progression rather than treating isolation, analysis, biological testing, and application as independent activities.

Across the four themes, several common trends become evident. Natural-product research is moving from broad screening toward integrated chemical and mechanistic characterization; from resource-intensive processing toward greener and more selective recovery; from single-product extraction toward comprehensive biomass utilization; and from descriptive phytochemistry toward an understanding of the genetic, environmental, and technological factors that shape metabolite production [23,24,25,26,27,28]. Advanced chromatography, spectroscopy, metabolomics, molecular docking, computational prediction, controlled-release systems, and material functionalization are increasingly being combined within these workflows.

The collection also reveals persistent challenges. Complex extracts are difficult to standardize, and variations in biological source, cultivation, processing, and analytical methodology can limit reproducibility. Biological activities reported in vitro do not always translate into efficacy, safety, or bioavailability in more complex systems. Furthermore, many environmentally promising processes remain difficult to scale economically, while claims of sustainability are not always supported by quantitative assessment [29].

Addressing these limitations will require several priorities. First, natural-product studies should adopt more transparent standards for source identification, sampling, extraction conditions, chemical characterization, and biological testing. Second, green and scalable recovery technologies should be evaluated together with downstream purification, formulation, and life-cycle performance. Third, structure–activity analysis and computational prediction should be integrated with experimental validation and toxicological assessment. Fourth, biomass valorization should aim for complete and efficient use of renewable feedstocks rather than the recovery of a single target compound. Finally, sustainable sourcing and biodiversity conservation must remain central to the development of nature-based technologies.

Interdisciplinary collaboration will be critical to achieving these goals. Chemists, biologists, agronomists, food scientists, pharmacologists, toxicologists, materials scientists, computational researchers, and engineers must work together to transform chemical diversity into reproducible knowledge and useful products. Stronger connections between academic research, industrial development, and regulatory science will also be needed to move promising discoveries beyond the laboratory.

As its Guest Editor, I am pleased to present this Special Issue as a contribution to the expanding field of nature-derived compounds. The papers assembled here demonstrate that natural resources remain a powerful platform for discovery, technological innovation, and sustainable development. More importantly, the collection shows that the future of the field lies in integration: linking biodiversity with chemical insight, efficient processing with rigorous evaluation, and scientific originality with environmental responsibility.

Nature’s molecular reservoir remains only partially understood, with countless metabolites yet to be identified and substantial research still needed to uncover their biological and therapeutic potential.

Nature is therefore not only a reservoir of molecules. It is also a source of functional principles and renewable materials that can guide the development of safer, more efficient, and more sustainable chemical solutions. The vast number of unknown metabolites underscores both the limits of our current understanding of nature’s molecular diversity and the considerable opportunities that remain for future research, so my hope as an editor is that a similar Special Issue will be published in the future reflecting new findings.

On this occasion, I thank the authors, reviewers, and the entire editorial team of MDPI Compounds for their contributions, support, and valuable collaboration.