# Potential of Plant Stem Cells as Helpful Agents for Skin Disorders--A Narrative Review
## 1 Introduction  
The Latin term '_senesx_' is used to denote an 'older adult' or 'old age' and the adjective'senectus' is the root of the English term'sensecence', which describes the process of gradual deterioration following development and maturation [1]. [PERSON] and [PERSON] were the first to formally describe the process of cellular senescence, which they observed in in vitro human diploid cells that reached their maximum proliferative capacity and ceased cellular division without any signs of cell death [2]. The skin, the human body's biggest organ, consists of three layers: the epidermis, the dermis, and the hypodermis (subcutaneous tissue) [3, 4, 5, 6]. It is also the most accessible organ, reacting to the external and internal environments, which affects its aging process [7, 8]. The exosomes which may accelerate the aging of the skin include environmental pollutants, tobacco smoke, and ultraviolet radiation (UVR). UVR has been estimated to account for over 80% of senescence caused by the external factors [9, 10]. The process of skin aging is intricate and encompasses all layers of the skin. It is coupled with the build-up of senescent cells and a phenomenon known as \"senescence-associated secretory phenotype\" (SASP) [11]. Senescent cells are irreversibly cell-cycle arrested via the p53-p21 CIP1 or the p16 hN4a-Rb axis, accumulate senescence-associated \(\beta\)-galactosidase activity (SA-\(\beta\)-gal), and exhibit typical morphology [1, 12]. SASP is defined as a combination of growth hormones, chemokines, cytokines, and proteases thatpromotes tumor development and inflammation [12]. Senescence, as a pleiotropic process, is discussed both in physiological conditions as well as in various, mainly age-related, skin disorders, e.g., skin cancers, psoriasis, pigmentation disorders, bullous pemphigoid, cutaneous lupus erythematosusous, and alopecia areata [7; 13]. Although the senescent cells positively affect wound healing and tissue repair, over time, their continuous presence and accumulation might be harmful [12]. Importantly, it should be emphasized that senescence and aging are closely connected but not synonymous processes [7]. Senescence contributes to aging and age-related diseases, but as a pleiotropic process, it is also linked with various physiological and pathological stages. It is crucial to identify and develop effective as well as safe sensotics/senostatics for topical therapy. Therefore, compounds attenuating or reversing senescence could be promising agents for anti-aging skin treatments. Apart from specific drugs whose anti-aging effectiveness has been observed, skin senescence can also be suppressed with natural bioactive products and medicinal plants [14; 15; 16; 17; 18]. The study of plant resources as natural antioxidants and enzyme inhibitors has focused on their relationship to skin barrier disturbance, inflammation, melanin hyperpigmentation, and different skin disorders. They have become valuable components of cosmetic formulations that aim to inhibit or impede senescent processes in the skin [19]. The use of plant extracts or organs (leaves, fruits, flowers, bark, and roots) in pharmaceutical and cosmetic contexts dates back to ancient times [20]. Active plant constituents are responsible for several features, including moisturizing, nonurishing, photoproduction, antioxidation, anti-wrinkling, astringency, cleaning, and whitening [16; 19; 21; 22; 23; 24; 25]. Worldwide interest in natural-based products has led to an increase in demand for these products and has developed a fast-growing market. It is estimated that the world's herb production reached 0.5 million tons per year, occupying around 70,000 hectares of cultivation area. However, conventional production of plant raw materials is highly dependent on climate conditions, soil composition, and the genetic makeup of the plants themselves. Thus, it is more difficult to obtain uniform raw materials for pharmaceutical and cosmetic production [26].