## 1 Introduction  
Natural plant-based extracts are currently garnering a lot of attention due to their multifunctional biological roles and their different industrial applications in foods, pharmaceuticals, and cosmetics. Indeed, plant-based extracts can be used as food additives, which is considered a sustainable development trend in the food industry [1]. Specifically, plant-based food additives can be used as preservatives to prevent food spoilage caused by microorganisms to prolong food shelf life, as antioxidants to stop or delay the autoxidation of foods, or as antimicrobials to protect from microbes and other predators [2]. In addition, plant-based food additives have gained a lot of attention because of their benefits over synthetic ones, including environmental protection, health benefits, and green safety and food legislation issues [2]. As a result, the development and application of plant-based food additives is an emerging and active field in the food industry [1]. In this study we focused on three natural extracts that are derive from three highly related medicinal plants within the _Greek flora: Hypericum perforatum_ (_H. perforatum_), _Pistacialentiscus var. Chia (P. lentiscus var. Chia), and Rosmarinus officinalis (R. officinalis). H. perforatum_ is a medicinal herb that is traditionally used to treat various ailments, including depression, anxiety, and inflammation. It is known that it contains a variety of phyto-chemicals, including flavonoids and hypericin, which are believed to have antioxidant, anti-inflammatory, and antimicrobial properties [3]. Specifically for foods, _H. perforatum_ can be found in a variety of food and beverage goods as a functional ingredient. According to previous studies, 0.5 g of _H. perforatum_ mixed with 100 g of wheat flour enhances the bioactive compounds of wheat cookies [4], and _H. perforatum_ water honey extract is used to extend the shelf life of bread [5]. In addition, it is reported that _H. perforatum_ is a safe and non-cytotoxic ingredient as it is used in pharmaceuticals, cosmetics, and foods [6; 7]. Mastic is a natural resin derived from the _P. lentiscus var. Chia_ tree and has been used for centuries for medicinal purposes and studied for its antifungal properties. Mastic has demonstrated antimicrobial properties against various strains of bacteria. Research has shown that mastic extract can inhibit the growth of bacteria associated with stomach ulcers and gastroenteritis [8]. Specifically, mastic can serve as an extra natural preservative in a variety of susceptible products such as cosmetics or pharmaceutics. In addition, in combination with other food additives, it has been shown to enhance the preservation and the quality of different products [9]. On the other hand, _R. officinalis_ L., either as extract or essential oil, is a rich source of phenolic compounds with anti-inflammatory [10], antidiabetic [11], hepatoprotective [12], and antimicrobial activity [13]. Both the extract and essential oil of _R. officinalis_ L. are used for the treatment of illnesses and in food preservation [13]. This rationale has stimulated consumer and industry interest in replacing or decreasing synthetic antioxidants in foods. The European Food Safety Authority (EFSA) has reviewed the safety of rosemary extract for use as a food additive [14]. In addition, _Saccharomyces cerevisiae_ (_S. cerevisiae_) has been studied extensively, because it is a microorganism with a high genetic diversification due to adaptations after many years of industrial applications that have resulted in the evolution of many different strains with distinct phenotypic characteristics [15]. Therefore, to facilitate research and draw conclusions, _S. cerevisiae_ is often chosen as a study model because it is harmless, easy to culture, and well-studied [16]. Yeasts, also, are more complex genetically and structurally than bacteria [17] and may be more resistant to various antimicrobial compounds.