Study on the antibacterial activity of six gingerol compounds in ginger
The excessive use of antibiotics has led to an increasingly serious problem of pathogen resistance. Once bacterial resistance is developed, it can not only be transmitted to offspring through genes, but also to other bacteria through bacterial binding. Experts are concerned that drug resistance may become a global disaster with no signs of relief. Developing new types of antibacterial drugs is an urgent task facing the world, and searching for antibacterial components from plant-based drugs is an important direction in the development of antibacterial drugs. Ginger plants are one of the important sources of antibacterial ingredients. In the past decade, multiple chemical compounds with excellent antibacterial activity have been discovered from ginger plants.

Ginger (Zingiber officinale Roscoe) is a traditional plant of the same origin as food and medicine, belonging to the ginger family and the ginger genus. Ginger has pharmacological effects such as anti-inflammatory, antibacterial, anti-tumor, antioxidant, promoting digestion, improving blood circulation, and strengthening the stomach and relieving pain. Gingerols are the spicy components and main active ingredients in ginger. Gingerol compounds have attracted attention due to their biological activities such as anti-tumor and antibacterial properties. [6] – gingerol and [6] – gingerol have good broad-spectrum antibacterial activity against efflux MRSA strains SA1199B (NorA), XU212 (TetK), and RN4220 (MSRA), and have strong inhibitory effects on R-plasmid binding transfer. Lee et al. found that [6] – gingerol, [8] – gingerol, and [6] – gingerol can inhibit the formation of biofilms in Candida albicans, but [10] – gingerol, [8] – gingerol, and [10] – gingerol, which have similar structures to them, did not show inhibitory activity at a concentration of 100 μ g/mL. Although some scholars speculate that the shortened chain length of gingerol like components may lead to a decrease in antibacterial activity, Lee’s research results suggest that the carbon chain elongation of gingerol and gingerol seems to lead to a decrease in their activity against Candida albicans.

Our research group found that ginger extract has significant antibacterial activity against more than 20 pathogenic bacteria, and the antibacterial activity of the extract is significantly enhanced after photochemical reaction. In the process of studying the antibacterial activity of ginger, our research group isolated six gingerol compounds. In order to further explore the relationship between the antibacterial activity of these compounds and the length of the fatty chain, we conducted a study on the antibacterial activity of these six gingerol compounds against 15 pathogenic strains, in order to find patterns among them.

We isolated and identified six gingerol compounds from ginger, and conducted antibacterial activity tests on these six compounds. Based on this, we preliminarily explored the structure-activity relationship. Overall, compared to gingerol compounds 4, 5, and 6, enol compounds 1, 2, and 3 exhibit inhibitory activity against more Gram positive bacteria; The antibacterial activity of gingerol compounds 4 and 5 against Gram negative bacteria is superior to that of enol compounds. Based on our antibacterial test data and combined with the research results of Lee et al., an increase in the length of the fatty chain of gingerol like components may lead to a decrease in antibacterial activity. Our antibacterial activity tests with Lee et al. only targeted gingerol compounds with fatty chain lengths of 5, 7, and 9 carbon atoms; As for fatty chains with less than 5 or more than 9 carbon atoms, further exploration is needed to determine whether the above rules still apply.
Gingerols are an important class of antibacterial components in ginger, and it is worth further exploring the potential antibacterial active ingredients or lead compounds from these components. This study can lay a foundation for the research and development of gingerol compounds with antibacterial activity and their antibacterial mechanisms.