# A Review on Flavonoids as Anti-_Helicobacter pylori_ Agents
## 3 Results
### Medicinal Plants and Their Potential Application
Furthermore, the fraction of polyphenols that reaches the colon unaltered is metabolised by microbial enzymes, enhancing systemic bioavailability and promoting beneficial effects on gut health, thereby creating an ideal environment for probiotic bacteria (Figure 2) [63; 64]. An example of the mutual relationship between gut microorganisms and polyphenols is the conversion of anthocyanins from red wine extracts into protocatechuric acid by colonic bacteria, which supports the growth of beneficial microbes such as _Bifidobacterium_ and _Lactobacillus_[65; 66]. The use of medicinal plants to prevent and treat _Helicobacter pylori_ infection represents a promising alternative therapeutic strategy [67; 68]. This approach is attributed mainly to the diverse mechanisms of action exhibited by flavonoids, which include binding to bacterial membranes, disrupting _H. pylori_ adhesion to host cells, and inhibiting the transcription of essential virulence genes such as _urese_, _CagA_, and _VacA_. Additionally, flavonoids can induce DNA damage by increasing hydrogen peroxide levels and interfere with transcription and translation processes critical for bacterial survival [67; 69; 70]. Flavonoids are a diverse and ubiquitous group of phenolics present in plants. Usually, they are formed by three rings named A, B, and C (Figure 2). These compounds can be mainly divided into seven groups: anthocyanins, flavonols, flavonols, flavanols, flavanones, isoflav, and chalcones [70] (Figure 3). They are found in fruits, vegetables, and medicinal plants. They have different pharmacological properties, including but not limited to antioxidant, antitumor, and anti-inflammatory. Due to their chemical structure, these compounds reduce reactive oxidative species (ROS) [67; 70]. In medicinal plants that contain flavonoids, naringenin--isolated from the flower of _Hibiscus rosa-sinensis_--also exhibited activity against \(H\). _pylori_. A potent antibacterial effect against \(H\). _pylori_ was demonstrated, with a minimum inhibitory concentration (MIC) of 100 mg/L [71; 72]. The flavonoids identified in almond skin extracts were epicatechin, naringenin, and protocatechuic acid, and the MIC50 values were 512, 256, and 128 ug/mL [73]. For extracts from _Cannabis sativa_\(L\) that were rich in naringenin, the MIC values ranged from 8 to 32 ug/mL. Other research on naringenin and its derivatives varies considerably, with MIC ranging from 8 to 1024 ug/L depending on the \(H\). _pylori_ strain tested [74]. An anti-biofilm effect was observed only for naringenin and myricetin. At a concentration of 200 uM, the naringenin derivative 7-O-butyl naringenin was found to be more than 10 times as potent as naringenin, exhibiting high effectiveness against \(H\). _pylori_[75]. Meanwhile, the glycoside forms of naringenin--naringin and prunin--exhibited a weaker and stronger inhibitory effect compared to naringenin at 0.5 mM [76; 77]. The importance of using plant extracts for \(H\). _pylori_ treatment has been reviewed [78]. Articles from 10 years (2015 to 2025) with in vitro assays were discussed in that study. The authors raised the importance of in vivo data, as those studies might provide more about mechanisms and be closer to human pharmacology. Some results showed that these extracts were significantly more efficient than antibiotic treatments, which could be very helpful to patients, as these extracts might not have so many side effects. The following plant extracts were identified by in vitro assays. _Alchorea triplinervia_ (Spreng.) Mull.Arg.,  
Figure 2: Polyphenol metabolism in the body. Schematic representation showing how polyphenols are used by our body. Created in BioRender. [PERSON], [PERSON] (2025) [[https://BioRender.com/m42e871](https://BioRender.com/m42e871)]([https://BioRender.com/m42e871](https://BioRender.com/m42e871)), accessed on 19 March 2025. Euphorbia hitta L., Euphorbia umbellata_ (Pax) [PERSON], _Jatropha podagrica_ Hook (leaves, stem, roots), _Euphorbia retusa_ [PERSON].