Metabolic diseases consist of multi-metabolic abnormalities associated with different metabolic syndromes, such as hyperglycemia, dyslipidemia, insulin resistance, obesity, oxidative stress, hypertension, and others. For the prevention and cure of metabolic diseases, physicians generally prescribe various synthetic drug agents, e.g., angiotensin-converting-enzyme inhibitors (for hypertension), non-sulfonylurea (for diabetes), and statin-lipid lowering agents (for hypercholesterolemia). Almost all synthetic drugs are associated with noticeable side effects, such as headache, dizziness, nausea, vomiting, rash, abdominal pain, liver disease, kidney disease, muscle weakness, and lactate acidosis.

Studies have uncovered that plant-derived polyphenols, such as phenolic acids, curcuminoids, stilbenes, lignans, flavonoids, flavonols, flavones, and anthocyanins, may exert potential antioxidant, anti-inflammatory, anti-hypertensive, hepato-protective, cardio-protective, anti-diabetes, and anti-obesity activity. Because of some undesirable features at the clinical level, e.g., gastrointestinal instability, uncontrolled release, poor absorption, high dose-induced toxicity, etc., many polyphenols cannot be successful as a potential therapeutic candidate. In the last decade, the delivery of polyphenols using well-developed micro and/or nano-carriers has gained much research interest and is producing promising results.

The aim of this Special Issue is to collate research on polyphenol-loaded carrier formulations related to biocompatibility, targeting efficiency, bioavailability, therapeutic efficacy in in vitro, in vivo models, and clinical subjects, as well as safety aspects and future prospects. Original research and review articles are welcome.

Potential topics include but are not limited to the following:

• Design, development, and in-depth characterization of carriers for the delivery of polyphenols
• Polyphenol-carrier interactions, stability, drug-release kinetics, and release mechanism
• Functional properties of carrier formulation, e.g., particle characteristics in the gastro-intestinal tract, intestinal mucus penetration, cellular uptake, and release pattern at the targeted site
• In vivo biodistribution and pharmacokinetic studies
• Pharmacological studies of polyphenols-based carriers concerning metabolic diseases, e.g., antiobesity, antidiabetic, etc.
• Development of novel or advanced carrier formulations for polyphenols targeting to ameliorate metabolic diseases
• Therapeutic efficacy of polyphenol-based carrier formulations against metabolic diseases including in vitro, ex-vivo, and in vivo studies
• Multi or dual delivery of polyphenols using a multi-functionalized carrier to achieve synergistic or additive therapeutic outcomes against metabolic diseases
• Toxicity aspects and biological safety of the carrier formulations in cellular and/or animal models
• Clinical trial studies on the efficacy of polyphenol-loaded carriers to treat metabolic diseases
• Systematic reviews and meta-analyses on the potential of polyphenol-loaded carriers for treating metabolic diseases