RESUMEN
Infection with Helicobacter pylori is strongly associated with gastric cancer and gastric adenocarcinoma. WHO classified H. pylori as a group 1 carcinogen in 1994. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures and fingernail inflammation. In this study, we isolated anti-H. pylori compounds from this plant and investigated their anti- and bactericidal activity. Compounds of 2-methoxy-1,4-naphthoquinone (MeONQ) and stigmasta-7,22-diene-3ß-ol (spinasterol) were isolated from the pods and roots/stems/leaves of I. balsamina L., respectively. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for MeONQ were in the ranges of 0.156-0.625 and 0.313-0.625 µg mL(-1), respectively, and in the ranges of 20-80 µg mL(-1) both of MICs and MBCs for spinasterol against antibiotic (clarithromycin, metronidazole and levofloxacin) resistant H. pylori. Notably, the activity of MeONQ was equivalent to that of amoxicillin (AMX). The bactericidal H. pylori action 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 the I. balsamina L. 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 of H. pylori infection.
RESUMEN
Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures, and fingernail inflammation. In this study, anti-H. pylori activity of I. balsamina L. was investigated. The MICs, MBCs, time-kill assay, and effect of environmental pH for the plant extracts were determined. The test H. pylori strains have resistance to clarithromycin (CLR), metronidazole (MTZ), and levofloxacin (LVX). From our results, all part (root/stem/leaf, seed, and pod) extracts of I. balsamina L. exhibited bactericidal H. pylori activity. Specifically, the pod extract had significantly lower MICs and MBCs (1.25-2.5 and 1.25-5.0 microg/ml, respectively). Of the five pod-extraction solvents, both ethyl acetate and acetone were the most efficient for the anti-H. pylori compounds of the pod extraction. The dose-dependency of the pod extract's bactericidal activity was H. pylori strain-dependent. Bactericidal H. pylori activity of the pod extract was not affected by the environmental pH (2-8). In summary, the acetone and ethyl acetate pod extracts of I. balsamina L. exhibited very strong anti-H. pylori activity. This activity exceeded that of MTZ and approximated to that of AMX.