Spicing up gastrointestinal health with dietary essential oils

Recent complex changes in social, dietary, and behavior routines led to a significant increase in functional and immune disorders of the human gastrointestinal tract. Volatile essential oils from major food commodities such as culinary and medicinal plants (spices) hold the potential to protect the digestive system from abusive agents and immune hypersensitivity by modulating inflammation and gut microbiome. Here we identify 8 botanical interventions including fennel ( Foeniculum vulgare Mill.), rosemary ( Rosmarinus officinalis L.), ginger ( Zingiber officinale Ros.), garlic ( Allium sativum L.), peppermint ( Mentha × piperita L.), bitter orange ( Citrus aurantium L.), cardamom ( Elettaria cardamomum (L.) Maton), and dill ( Anethum graveolens L.) essential oils that prevented gastric ulcer formation, reduced production of gastric acids, or promoted upper gastrointestinal healing in preclinical or early phase human studies. These oils were further evaluated for their biochemical constituents, antibacterial, anti-inflammatory, and antioxidant activities to provide insight into potential mechanisms of action in vivo. With a few current human studies in support of these findings, there is a critical opportunity to further examine clinical effects, efficacy, and acceptability of botanical essential oils to manage upper gastrointestinal health and wellbeing. Graphic abstract