## 1 Introduction  
Advances in biological research have shown the extraordinary potential of plant extracts (PEs) as important cosmetic raw materials for use in cosmetic formulations. PEs are obtained by isolating the necessary bioactive components from the plant material using processes such as maceration, solvent extraction, supercritical fluid extraction, or Soxhlet extraction [1]. Fermented plant extracts (FPEs) have recently been exploited as new cosmetic raw materials due to their antioxidant, anti-ageing, moisturising, and anti-allergenic characteristics, as well as increased bioactivity, biocompatibility, and bioavailability [2; 3; 4; 5; 6; 7]. Obtaining FPEs entails not only removing the necessary bioactive components from plant material but also degrading or transforming undesired substrata into acceptable products via the activity of suitable microbes. Microorganisms break down plant components in plant materials, enhancing their biological activity by turning high-molecular molecules into low-molecular structures. The structural breakdown of the cell walls of plant raw materials and the hydrolytic activity of microorganisms during the fermentation increases the concentration of anthocyanins, flavonoids, organic acids, proteins, ceramides, amino acids, or biological enzymes [8]. During fermentation, bacteria and fungi may produce antioxidants by enzymatically converting phenolic glycosides found in plant source materials into free polyphenols [6; 7; 9; 10; 11]. Blueberry fruit fermentation in the presence of lactic acid bacteria (LAB) _Lactobacillus plantarum_ and _fermented_, as well as black tea with kombucha, both indicate the existence of phenolic components in (fermented plant extracts) FPEs [12]. Polyphenols, including chlorogenic acid and caffeoyl derivatives, as well as flavonoids, may suggest the biological potential of yerba mate's FPE for dermatological uses [13]. Polyphenolic compounds (a class of plant-derived chemicals having a phenolic structure) have piqued the interest of the beauty industry due to the multiple health advantages associated with their antioxidant and anti-inflammatory properties [2; 14]. Polyphenols scavenge free radicals, neutralising their detrimental effects and decreasing oxidative stress in the body while also lowering risk factors for chronic illnesses such as cardiovascular disease and some malignancies [1; 15]. In the presence of _Pediococcus acidilactici_ (KCCM 11614), the fermented plant extract from _Magnolia denudata_ flowers showed more anticancer activity against human gastric adenocarcinoma (AGS) and human colon cancer LoVo cells than the untermented plant extract [16]. Plant extracts produced through the fermentation of _Rhus verneificlua_ bark shown anticancer efficacy against the colon cancer cell line HCT-116, as well as the potential to trigger apoptosis and block the hedgehog pathway [17]. _Ophitoggon japonicus_ extract fermented with the fungus _Cordyceps militaris_ (first fermentation for 10 days) and then fermented with a mixture of bacterial strains _Lactobacillus plantarum_, _Enterococcus facicum_, and _Bifidobacterium longum_ (second fermentation for 2 days) can prevent cardiovascular diseases associated with vascular smooth muscle cell proliferation and migration [2; 16; 18]. Furthermore, the fermented plant extract produced from ginseng in the presence of Aspergillus usamii KCTC 6954 demonstrated stronger anticancer activity against human hepatoma cells (HepG2s) and the human colon cancer cell line (DLD-1) than the untermented ginseng extract. Ginsing extract was treated with \(\beta\)-glucosidase from Aspergillus usamii KCTC 6954 due to the fact that this enzyme is capable of converting major ginseng into minor ginseng. The fermentation process increased the concentration of smaller ginseng, enhancing the anticancer effect of the fermented ginseng plant extract compared to the non-fermented extract [14; 19].