Bioactive Properties of Campomanesia lineatifolia: Correlation Between Anti-Helicobacter pylori Activity, Antioxidant...

Helicobacter pylori is found in the stomach of patients with chronic gastritis and peptic ulcers, infecting approximately half of the world's population. Current treatment for H. pylori infection involves a multi-drug therapeutic regime with various adverse effects, which leads to treatment abandonment and contributes to the emergence of resistant strains of H. pylori. Previously, we demonstrated that the essential oil of Campomanesia lineatifolia leaves exhibited an anti-H. pylori activity. In this study, we aimed to evaluate the phenolic content of the phenolic-rich ethanol extract (PEE) from C. lineatifolia and its anti-H. pylori and antioxidant properties. Additionally, the anti-H. pylori activity was assessed in polar and non-polar fractions from PEE, isolated myricitrin (MYR) and a mixture of myricitrin and quercitrin (MYR/QUER) from polar fractions, and aqueous extract (tea) to correlate the responsible fractions or compounds with the observed activity. Broth microdilution assays were performed to assess the anti-H. pylori activity using type cultures (ATCC 49503, NCTC 11638, both clarithromycin-sensitive) and clinical isolate strains (SSR359, clarithromycin-sensitive, and SSR366, clarithromycin-resistant). The antioxidant activity was evaluated using the DPPH assay. The total tannin and flavonoid contents were determined using the hide-powder method, the Folin-Ciocalteu reagent, and the aluminium chloride colourimetric assay, respectively. The tea (MIC 1:100), PEE, polar and non-polar fractions, MYR, and MYR/QUER inhibited the growth of H. pylori strains tested (MIC values ranging from 0.49 to 250 μg/mL). The antioxidant assays revealed that PEE exhibited a higher antioxidant activity (EC₅₀ = 18.47 μg/mL), which correlated to the high phenolic content (tannin and flavonoid, 22.31 and 0.15% w/w, respectively). These findings support the traditional use of C. lineatifolia as a multitarget medicinal plant for treating gastric ulcers and reinforce the potential use of the species as a coadjuvant in therapeutic regimes involving patients with resistant H. pylori infection.