Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the most prevalent chronic liver diseases worldwide, involving multiple pathological mechanisms such as lipid metabolism disorders, oxidative stress, chronic inflammation, insulin resistance, and dysregulation of the gut–liver axis. Currently, there remains a lack of effective and long-term safe therapeutic strategies for MASLD, necessitating the development of novel interventions. Plant-derived exosome-like nanovesicles (PELNs) represent naturally secreted nanoscale vesicles derived from plant cells. Their advantages, including extensive availability, high biocompatibility, low immune activation, remarkable stability, and convenient oral administration, make them attractive platforms for therapeutic delivery. PELNs can not only encapsulate natural bioactive compounds such as polyphenols, alkaloids, terpenoids, and polysaccharides but also serve as drug delivery vehicles to achieve liver-targeted transport and synergistic therapy. Current evidence for PELNs in MASLD is predominantly preclinical. In vitro studies have provided mechanistic insights into their effects on lipid metabolism, oxidative stress, inflammatory signaling, and hepatocellular injury, whereas animal studies have demonstrated improvements in hepatic steatosis and related metabolic abnormalities for selected PELNs. A smaller number of studies have investigated tissue distribution, oral uptake, or preliminary biosafety. However, systematic pharmacokinetic, long-term toxicological, and target-species clinical evidence remains insufficient. Accordingly, the therapeutic effects discussed in this review should be interpreted primarily as preclinical findings, and the applicability of PELNs in veterinary practice remains to be established.

Colitis is a chronic relapsing inflammatory disorder characterized by persistent mucosal inflammation, epithelial barrier disruption, oxidative stress, immune dysregulation, and gut microbiota imbalance. Although current therapies have improved disease management, their long-term use is still limited by incomplete response, relapse, adverse effects, and high cost. Natural products have attracted increasing attention as promising candidates for colitis intervention because of their structural diversity, broad bioactivity, and multitarget regulatory potential. In veterinary medicine, colitis and colitis-related intestinal inflammatory disorders are also clinically relevant in companion animals, horses, and food-producing animals, where they contribute to diarrhea, impaired intestinal barrier function, reduced performance, treatment costs, and antimicrobial-use concerns. Therefore, natural products may have additional value as adjunctive, nutritional, or microbiota-modulating strategies in veterinary and comparative gastroenterology. This review summarizes the major categories of natural products investigated for colitis, including flavonoids, polyphenols, alkaloids, terpenoids, saponins, polysaccharides, plant extracts, and traditional herbal formulas, and discusses their principal mechanisms of action, such as anti-inflammatory activity, attenuation of oxidative stress, restoration of intestinal barrier integrity, modulation of immune responses, regulation of gut microbiota, and control of programmed cell death. We also highlight the major limitations of current research, including overreliance on preclinical models, insufficient target validation, poor bioavailability, and limited clinical evidence. Overall, natural products represent an important source of therapeutic candidates for colitis, but their clinical translation will require deeper mechanistic studies, standardized evaluation, and well-designed clinical investigations. Importantly, future studies should distinguish phenotype-associated changes from causal mechanisms by integrating direct target engagement, functional rescue experiments, microbiota-causality validation, and standardized pharmacokinetic and safety assessment.