The extract may also be able to limit bacterial growth by acting directly against the bacterium, but further studies will be devoted to better clarify the role of specific classes of polyphenols present in Rhus coriaria L (Sumac), the authors of this study say.
The researchers from the University of Milan said that bioactivity was observed at concentrations easily achievable by oral consumption of Sumac.
In a previous study, researchers showed the positive effect the herb had on skin inflammation but say this study was aimed at further demonstrating its potential role in inflammatory disorders focusing on gastritis.
The brown/red fruits of Rhus coriaria are used as a very popular spice in food production for their sour lemony taste. Phytochemical characterization of berries showed the occurrence of different antioxidants belonging to several classes of polyphenols, among which flavonoids and gallotannins are the most abundant.
Red fruits are traditionally used in Persian medicine to treat diarrhoea, haemorrhoids, gout, and decrease cholesterol, uric acid, and blood sugar levels, and for a variety of other biological activities. Much evidence supports the pharmacological and nutraceutical properties of Sumac in a variety of diseases the researchers wrote.
They said: “Moreover, additional studies demonstrated interesting effects in inflammatory conditions, including the reduction of pro-inflammatory mediators.
“Gastritis is considered an inflammatory-based condition, which is provoked by several risk factors that include stress, alcohol abuse, the use of drugs such as non-steroidal anti-inflammatory drugs (NSAIDs), and bile reflux.”
They addeed that H. pylori is a Gram-negative bacterium infecting around 50% of people all over the world, the bacterium can cause acute or chronic gastritis or digestive problems and infection with H. pylori leads to the development of more severe diseases, such as a peptic ulcer or gastric cancer.
The World Health Organization (WHO) assessed H. pylori as a class I carcinogen for gastric cancer in 1994, the researchers noted.
The aim of the present work is to assess the potential anti-inflammatory and anti-bacterial activity of Rhus coriaria extracts in human gastric epithelial cells challenged with H. pylori or skin inflammation.
Since Sumac fruits contain several classes of constituents with different polarity, another purpose of the study, the research team said, was to identify the most suitable extract type in terms of biological activity and future commercialisation as food supplement ingredient.
For this purpose, they wrote, different polar extracts (water, ethanol-water, ethanol, ethanol macerated, acetone and ethylacetate) were investigated in gastric epithelial cells challenged by skin inflammation or gastric inflammation.
They said: "The ethanolic extracts showed the major phenolic contents, correlating with lower half maximal inhibitory concentrations on the release of interleukin-8 and interleukin-6 induced by TNF-α. Similarly, they inhibited IL-8 release during Helicobacter pylori (H. pylori) infection and exhibited a direct antibacterial activity at comparable concentrations (minimum inhibitory concentration)."
They noted that the phenolic content and the bioactivity of ethanol water were maintained after simulated gastric digestion and were associated with nuclear factor kappa B (NF-κB) impairment, considered the main putative anti-inflammatory mechanism.
They said: "On the contrary, an anti-urease activity was excluded. To the best of our knowledge, this is the first demonstration of the potential role of Sumac as a nutraceutical useful in H. pylori-related gastritis."
The researchers tested a total of six extracts and of those the ethanol-water extract showed promising activity as anti-inflammatory and anti-H. pylori agent when subjected to an in vitro mimicked gastric digestion.
They added: “This suggested the beneficial properties of Sumac towards the gastric mucosa and its possible use as an ingredient of food supplements able to prevent inflammatory-based gastric diseases induced by H. pylori infection, also limiting bacterial growth.”
The Nutraceutical Properties of Sumac (Rhus coriaria L.) against Gastritis: Antibacterial and Anti-Inflammatory Activities in Gastric Epithelial Cells Infected with H. pylori
Authors: Martinelli et al