Table 5.

Quantification of the cellular uptake of PLP and PI-h by H. pylori 26695 strain cells.

Compound	Starting inhibitor concentration [µM]	Method	Observation wavelength [nm]	Intracellular accumulation [µM]	t-test
PLP	390	UV absorption	388	84.7 ± 17.6 after 4 h 100.4 ± 16.3 after 8 h	****
PI-h	325	UV absorption	318	−8.9 ± 4.9 after 4 h −10.1 ± 8.2 after 8 h	ns
	35.4	UV absorption	318	−1.88 ± 0.77 after 4 h 0.80 ± 0.53 after 8 h	ns
					ns
	35.4	LC-MS	–	0.10 ± 0.84 after 4 h 3.58 ± 0.55 after 8 h	ns ***

Notes: The extracellular inhibitor concentration was determined by UV absorption spectra of the tested compounds and LC-MS detection methods ¹⁷. The t-test was used to check for a significant difference in the extracellular inhibitor concentration between supernatants incubated with and without H. pylori cells. The intracellular accumulation of each compound was determined using Equation (3) as described in the text. Results of the t-test are marked as follows: **** p < 0.0001; *** p < 0.001; ns p > 0.05, no significant difference.