## 1 Introduction  
An upsurge of interest in functional foods containing prebiotic ingredients and probiotic microorganisms is witnessed today because of the multiple associated effects. Probiotics have been described by the World Health Organization (WHO) as 'live microorganisms which when administered in adequate amounts, confer a health benefit on the host' [1]. Prebiotics refer to dietary non-digestible fibers that have a stimulatory effect on beneficial microbes, such as bifidobacterial and lactobacilli and manipulate the microbiome of the gastrointestinal tract (GI) of the host [2; 3; 4].  
Lately, polyphenols have already gained scientific and industrial interest as growth stimulators for probiotics. Polyphenols are present in significant amounts in medicinal plants and, along with polyphenols, are plant metabolites that have illustrated a variety of biological actions, making them strong candidates as dietary ingredients. Their activity toward humans is typically mediated through interaction with intestinal microorganisms because of their limited absorbability in the digestive tract. Therefore, they are characterized as a novel class of prebiotics [5]. _In vitro_ studies indicated that they may have a dual beneficial effect by simultaneously inhibiting infections and promoting health-promoting bacteria.  
Although there is a lack of evidence for the growth stimulatory effect of _A. citrodora_ extracts on lactobacilli strains, similar experiments available in the literature demonstrate that the effect of herbal extracts varies and depends usually on the genus, species, and microbial strain, as well as on the extraction method [6]. Certain lactic acid bacteria (LAB) have the ability to degrade certain phenolic compounds found in food, including those with high antioxidant activity [7; 8], suggesting increased cell growth of probiotic bacteria in culture media supplemented with plant extracts.  
Traditionally, medicinal plants have been consumed by humans for centuries, and plant-based therapies are among the most significant treatment modalities used in traditional medicine of diverse cultures. Plant extracts' wide spectrum of biological activities could be generally linked to their chemical composition [9]. Moreover, as natural alternatives to synthetic food preservatives, plant extracts constitute a potential source of antimicrobial compounds [10].  
_Aloysia citrodora_ (common name lemon verbena), a plant from the family of _Verbenaceae_, is one of the well-known medicinal plants with a variety of therapeutic uses [11]. Several studies have shown that _A. citrodora_ exhibits therapeutic properties with respect to insomnia, anxiety disorders, asthma, fever, diarrhea, and bloating [12]. The antibacterial, antifungal, anti-inflammatory, and antioxidant properties of verbena infusion have also been noted [9; 11; 13; 14; 15].  
Natural antioxidants included in medicinal herbs are responsible for inhibiting reactive oxygen species and lowering the negative effects of oxidative stress. Studies from several countries in the literature revealed the antioxidant activity of extracts from _A. citrodora_. For example, assessment of malondialdehydedehyde (MDA) formation, ferric-reducing ability of plasma (FRAP), and superoxide dismutase activity (SOD) in the plasma samples after oral administration of _A. citrodora_ extract in rats demonstrated the potent antioxidant activity of the plant [11].  
The aim of the present work was to unveil the phytochemical profile of the plant extracts, the antioxidant activity, and the prebiotic potential of the _A. citrodora_ aqueous and ethanolic extracts to promote the growth of _Lacticaseibacillus rhamnosus_ strains and suppress the evolution of common food-spoilage and pathogenic bacteria. The procedure followed for the identification of the compounds and the evaluation of the biological activity of the extracts is shown in Figure 1.