Uncovering the gastroprotective properties of araucaria brown propolis and its active compound, abietic acid

Although Araucaria brown propolis is a singular propolis with potential therapeutic applications, its anti-ulcer activity remains unexplored. This study investigated the gastroprotective effects of Araucaria brown propolis hydroalcoholic extract (HeBPA, 30- 300 mg/kg and its isolated compound, abietic acid (AA) in corresponding doses to its content in HEBPA. The extract's anti-ulcer activity was evaluated using acidified ethanol-induced gastric ulcers and pylorus ligation to assess gastric antisecretory activity. Additionally, the study examined histological, oxidative, and inflammatory parameters, and the extract's anti-Helicobacter pylori and cytotoxic effects. The 100 mg/kg oral dose of HeBPA promoted gastroprotection by 69.63% by increasing antioxidant defenses (GSH, CAT, and SOD) and reducing MPO activity and MDA levels in ulcerated mucosa. This gastroprotective effect was not due to antisecretory activity, but rather involved non-protein sulfhydryl compounds, alpha-2 adrenergic receptors, prostaglandins, and nitric oxide, as evidenced by the abolition of the effect with L-NAME, NEM, indomethacin, or yohimbine pre-treatment. HeBPA increased mucin stained by PAS in the gastric mucosa and prevented histological damage, reducing edema and inflammatory infiltrate. Additionally, HeBPA promoted fibroblast proliferation at 1 µg/mL, but showed no antibacterial activity against H. pylori (MIC > 1000 µg/mL). In addition, AA at 17 mg/kg reduced by 44.82% the ethanol induced- ulcers. These findings contribute to validate the anti-ulcer effect of Brazilian Araucaria brown propolis, highlighting its potential as a natural resource for developing new gastric ulcer treatments. Notably, AA does appear to be a key bioactive compound responsible for this effect.