Bioactive Compounds and In Vitro Antibacterial Activity of Hemp Leaves and Inflorescences as Potential Functional Feed Ingredients for Canine Nutrition.

Hemp (Cannabis sativa L.) inflorescences have been extensively characterized for their bioactive compounds, whereas less information is available on hemp leaves despite their potential as a source of nutrients and phytochemicals. This study compared leaves and inflorescences of four organically grown hemp cultivars (Finola, Futura 75, Dioica, and Kompolti) in terms of cannabinoid, terpene, and fatty acid profiles, lipid quality indices, and in vitro antibacterial activity. Antibacterial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was evaluated using MIC, MBC, and time-kill assays. Total cannabinoid content was approximately 2.7-fold higher in inflorescences than in leaves, which were also generally richer in terpenes. Leaves showed a more favorable fatty acid profile, with higher n-3 polyunsaturated fatty acid proportions and a lower n-6/n-3 ratio. All extracts exhibited antibacterial activity. Among the tested bacteria, S. aureus was the most susceptible to the hemp extracts, with both growth inhibition and bactericidal activity observed at the lowest tested concentration (MIC/MBC = 0.005%), compared with 0.625% for E. coli and 1.25-2.5% for P. aeruginosa, depending on the extract. Finola and Kompolti inflorescence extracts showed the fastest bactericidal activity against S. aureus. These findings demonstrate distinct and complementary characteristics of hemp leaves and inflorescences and provide a basis for further investigation of their potential relevance to canine nutrition.