Cloves, Eugenol, and Metabolic Regulation: Properties, Supplementation, and Uses in Chronic Diseases

Cloves are an ancient, intense spice surprisingly rich in active compounds. In culinary contexts, they are valued for their warm, pungent aroma, but in recent years, they have also attracted interest in nutritional and biological fields due to the presence of eugenol, a phenolic molecule—that is, a plant substance with chemical properties typical of phenols—which represents one of the main constituents of their functional profile. When discussing cloves, however, it is important to distinguish between culinary use, extract, and essential oil, because concentration, exposure, and biological potential are not equivalent. This distinction is central to correctly interpreting studies on glycemia, inflammation, oxidative stress, hepatic metabolism, and cellular regulation, without overestimating the effects of a spice that remains primarily a food and only in some cases a possible basis for more concentrated formulations. In the context of metabolic regulation, cloves are studied primarily for their interaction with mechanisms such as insulin resistance (i.e., the reduced ability of tissues to respond to insulin), AMPK (a protein that functions as a cellular energy sensor), mTOR (a signaling pathway that regulates growth and protein synthesis), autophagy (the process of recycling cellular components), and glucose uptake in peripheral tissues. However, the available literature is heterogeneous: many data are preclinical, while human evidence is still limited and should be interpret