Plants are constantly in contact with various microorganisms such as viruses, bacteria and fungi.
Interactions between plants and microbes can also be useful, but many of the plant ones are pathogens that compromise plant development, reproduction and growth.
To defend themselves, plants produce some defensive compounds against biological attacks. These have been tested in the prevention of bacterial or viral infections also in humans.
Ginseng is one of the best known medicinal herbs. Ginseng extracts, as well as single or multiple derivative components, have shown a marked anti-microbial activity.
Each microorganism has its own specific mode of action, by which the host survives and / or infects. Ginseng shows its anti-bacterial ability thanks to the inhibition of these modalities.
Generally speaking, bacterial adhesion to plant cells is the result of the interaction between the bacterial adhesin and the carbohydrates placed on the surface of host cells.
Some studies have shown that ginseng polysaccharides could interact with microbes interrupting microbial adhesion on host cells and blocking the onset of infectious diseases.
For example, the pectins of the ginseng PG-F2 and PG-HMW showed an anti-adhesive activity against various microorganisms, such as: Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Propionibacterium acnes and S. aureus.
These two pectins do not influence microbial growth directly, but the percentages of microbial attack decrease; this suggests that the polysaccharides of ginseng play a potentially anti-adhesive role.
Furthermore, ginseng-isolated polyacetylene has direct bactericidal effects. Four different polyacetylene compounds have been used to treat various gram-positive organisms (methicillin resistant: Escherichia coli and Serratia marcescens ) and gram negative ( S. aureus and Bacillus subtilis ), measuring their minimum inhibitory concentrations. The results show that polyacetylene compounds are effective against bacterial infections and that the level of antibacterial activity depends on the structural characteristics of polyacetylene.
Furthermore, although treatment with Ginsan does not appear to have any direct effect on bacterial killing in vitro, pre-treatment in mice shows greater anti-staphylococcal and phagocytic activity, decreasing the number of bacteria present in the spleen, kidney and blood.
Ginseng polysaccharides and red ginseng extract (RGE) have been shown to have some protective effects against Helicobacter pylori, as a cause of gastric inflammation, ulcer and damage to cellular DNA. Through the treatment with the active ingredients mentioned above, H. pylori cannot attack the gastric cells and initiate the inflammatory response. Furthermore, RGE significantly reduced the resulting DNA damage of the affected cells.
Furthermore, the literature attributes an anti Pseudomonas activity to ginseng. Mice treated with aqueous ginseng extracts, suffering from pulmonary infection (from P. aeruginosa ) similar to cystic fibrosis, show less replication of the pathogen. Although these extracts do not directly inhibit the growth of P. aeruginosa, they act by suppressing the synthesis of virulence factors.
