Investigations into the Antibacterial Activities of Phytotherapeutics against 'Helicobacter pylori' and 'Campylobacter jejuni'

The prevalence of gastric diseases is increasing with 'H. pylori', the causative agent of acute and chronic gastritis, being a major predisposing factor for peptic ulcer disease and gastric carcinoma. 'C. jejuni' is the most common cause of enteric infections, particularly among children, resulting in severe diarrhoea. Increasing drug resistance of these bacteria against standard antibiotics, and the more widespread use of herbal medicines, favours investigations into additional anti-'Helicobacter' and anti-'Campylobacter' effects of phytotherapeutics that are already used for their beneficial effects on bowel and digestive functions. Twenty-one hydroethanol herbal extracts and four essential oils were screened for antibacterial activity using a modification of a previously described micro-dilution assay and compared with the inhibitory effects of antibiotics. The herbal extracts showing the highest growth inhibition of 'C. jejuni' were 'Calendula officinalis, Matricaria recutita, Zingiber officinale', 'Salvia officinalis, Foeniculum vulgare' and 'Silybum marianum'. Agrimonia eupatoria, Hydrastis canadensis, Filipendula ulmaria' and 'Salvia officinalis' were the most active herbal extracts in inhibiting the growth of 'H. pylori'. This study provides evidence for additional beneficial effects of phytotherapeutics marketed for their gastrointestinal effects and identified new beneficial antibacterial effects for some herbal medicines not currently recommended for gastrointestinal problems.