Interaction of Human Gut Microflora with Commonly Consumed Herbs and Spices: a review

Herbs and spices are used since time memorable to transfuse color and add flavors to food. Their antibacterial properties also help preserve raw and cooked foods. Various diets composed of herbs and spices, as consistent with various researches, have been shown to influence life within the human digestive tract. This modulation forms the basis of various health effects that the herbs and spices and the microflora have on the human health. The intestinal microbiota is engaged in a critical function of promoting health, composed of favourable microbes (Lactobacillus and Bifidobacterium) and potentially harmful microorganisms (Salmonella thyphimurium and Escherichia coli). Spices and herbs make double oddities, i.e., inhibiting the proliferation of hazardous microbes while promoting favorable ones. The paper reviews the relevant manuscripts published in the past 20 years to understand the microbial modulation dynamics of herbs and spices. PubMed, Mendeley, SciELO, Scopus, Science Direct, and other peer-reviewed databases were accessed for the review. Microbial modulation is achieved by means of herbs and spices owing to the reduction of oxidative stress caused by reactive oxygen radicals, such as OHˉ, singlet O2, hydrogen peroxide, and superoxide radical, which leads to a threat to the intestinal microbiota. Spices and herbs have essential oils that serve as prebiotics, reducing the demand to impart artificial antioxidants, thus avoiding the associated health risks. Thus, the present review explores the mechanisms and underlying functions of herbs and spices in the human gut biome.