In VitroActivity of 2-methoxy-1,4-naphthoquinone and Stigmasta-7,22-diene-3β-ol fromImpatiens balsaminaL. against Multiple Antibiotic-ResistantHelicobacter pylori

Abstract

Infection withHelicobacter pyloriis strongly associated with gastric cancer and gastric adenocarcinoma. WHO classifiedH. pylorias a group 1 carcinogen in 1994.Impatiens balsaminaL. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures and fingernail inflammation. In this study, we isolated anti-H. pyloricompounds from this plant and investigated their anti- and bactericidal activity. Compounds of 2-methoxy-1,4-naphthoquinone (MeONQ) and stigmasta-7,22-diene-3β-ol (spinasterol) were isolated from the pods and roots/stems/leaves ofI. balsaminaL., respectively. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for MeONQ were in the ranges of 0.156–0.625 and 0.313–0.625μg mL−1, respectively, and in the ranges of 20–80 μg mL−1both of MICs and MBCs for spinasterol against antibiotic (clarithromycin, metronidazole and levofloxacin) resistantH. pylori. Notably, the activity of MeONQ was equivalent to that of amoxicillin (AMX). The bactericidalH. pyloriaction of MeONQ was dose-dependent. Furthermore, the activity of MeONQ was not influenced by the environmental pH values (4–8) and demonstrated good thermal (121°C for 15 min) stability. MeONQ abounds in theI. balsaminaL. pod at the level of 4.39% (w/w db). In conclusion, MeONQ exhibits strong potential to be developed as a candidate agent for the eradication ofH. pyloriinfection.