Gastric administration of garlic powder containing the trpa1- agonist allicin induces specific epigastric symptoms and gastric relaxation in healthy subjects.

Abstract

TRPA1 is an excitatory ion channel and is involved in sensory processes including thermal nociception and inflammatory pain. The allicin in garlic is a strong activator of the TRPA1 channel. To evaluate the effect of intragastric garlic powder containing allicin on perception, gastric tone, and mechanosensitivity. An infusion-barostat balloon assembly was used for infusion of test solutions, for distension, and to measure proximal gastric compliance and tone. After an initial open label dose finding with 1g, 2g, 3.75g, and 7.5g commercially available garlic powder, a bolus of 2g garlic powder (11mg allicin)/60mL H2 O was considered to induce moderate but constant sensation and was used hereafter in a placebo-controlled, single-dose, double-blind, randomized study in 7 volunteers to evaluate gastric sensation, tone, and mechanosensitivity. Bolus injection of garlic caused immediate epigastric symptoms, mean aggregate symptom scores (AUC in 15minutes) were 106±49 vs. 35±30 after placebo (P=0.01). Garlic induced significant epigastric pressure, stinging, and warmth (P<0.01 vs. placebo), while intensity of cramps, satiety, nausea, and pain was not significantly different to placebo (P>0.05). Garlic induced an immediate, short lived fundic relaxation (balloon volume 627±349mL vs. -145±120mL; P<0.02). No effect of allicin on proximal gastric mechanosensitivity and compliance was observed (NS). Garlic containing allicin induces immediate epigastric symptoms of pressure, stinging, and warmth and induces fundic relaxation but does not influence mechanosensitivity or compliance. TRPA1 is a receptor that is involved in gastric sensation and motility.