Enterobacteriaceae are widely present in many environments related to humans, including the human body and the food that they consume, from both plant or animal origin. Hence, they are considered relevant members of the gastrointestinal tract microbiota. On the other hand, these bacteria are also recognized as putative pathogens, able to impair human health and, in food, they are considered indicators for the microbiological quality and hygiene status of a production process. Nevertheless, beneficial properties have also been associated with Enterobacteriaceae, such as the ability to synthesize peptides and proteins, which can have a role in the structure of microbial communities. Among these antimicrobial molecules, those with higher molecular mass are called colicins, while those with lower molecular mass are named microcins. In recent years, some studies show an emphasis on molecules that can help control the development of pathogens. However, not enough data are available on this subject, especially related to microcins. Hence, this review gathers and summarizes current knowledge on colicins and microcins, potential usage in the treatment of pathogen-associated diseases and cancer, as well as putative applications in food biotechnology.

The present study was designed to evaluate the effects of eighteen different extracts derived from basil (Ocimum basilicum L.) leaves on spontaneous contractions, as well as contractions induced by potassium chloride (KCl) and acetylcholine in the ileum of rats, under in vitro conditions. The extracts were prepared with 96% v/v, 80% v/v, and 60% v/v ethanol, and absolute (100%) v/v, 80% v/v, and 60% v/v methanol, employing extraction techniques that included maceration, digestion, and sonication-assisted methods. Chemical characterization of the extracts revealed the presence of various phenolic acids, including rosmarinic, chlorogenic, caftaric, salvianolic acid B, cinnamic, caffeic, and chicoric acid, as well as flavonoids such as rutin and salvigenin. The evaluated extracts produced significant, concentration-dependent inhibitory effects on rat ileal contractions. Notably, the extract obtained via maceration with 80% methanol exhibited the most pronounced relaxant effects on spontaneous muscle contractions, achieving a maximum reduction of 46.16 ± 2.11%. Furthermore, the extract prepared with the same solvent using sonication-assisted extraction demonstrated superior efficacy in diminishing both the frequency and amplitude of KCl-induced ileal contractions, reducing contraction intensity caused by elevated potassium ion levels to 59.48 ± 3.34% at a maximum concentration of 1.5 mg/mL, thereby indicating its potential as a potent calcium channel blocker. Additionally, the extract prepared with 60% methanol through sonication-assisted extraction resulted in the most substantial reduction of acetylcholine-induced ileal contractions, decreasing contraction intensity to 35.74 ± 1.54% at the maximum concentration of 1.5 mg/mL, which suggests a high level of neurophysiological activity. By comparing extracts with different phytochemical profiles, this study provides additional insight into how variations in phenolic composition may influence different mechanisms of smooth muscle relaxation. This study affirms the significant spasmolytic properties of basil leaf extracts, thereby supporting their potential application in the management of gastrointestinal motility disorders.