# Potential of Plant Stem Cells as Helpful Agents for Skin Disorders--A Narrative Review
## 3 Divide and Conquer: Harnessing Biotechnology for Plant Stem Cell Cultivation  
Plants are totipotent, which means they can grow, develop (self-renewability), and differentiate cells to regenerate whole plant bodies for an unlimited period of time [28; 29]. That ability is lost by some animal cells after the embryonic phase. Primary stem cells in intact plants are established during the process of embryogenesis. They are later localized in the specialized meristem structure in the shoot (shoot apical meristem--SAM), root (root apical meristem--RAM), and (pro)cambium [28; 30; 31]. A transit-amplifying matrix cell population in the meristem peripheral zone surrounds the stem cells in the shoots. Meanwhile, stem cells in the root rely on the quiescent center as the source of the maintenance signal [30]. Secondary meristems established during the post-embryogenesis phase include cambium, phellogen, and traumatic meristem (callus). As seen in Figure 1, the callus, a collective unorganized cell mass, can still be generated by the whole plant body in response to stressors (physical, chemical, or biological) [28; 32]. Figure 1: Plant callus, the unorganized cell mass, which has been obtained and maintained through the use of biotechnological methods, is capable of producing a higher quality of secondary metabolite compounds and has the additional benefits of continuous production, a higher production yield, and a phytochemically uniform product. Selected lines of stabilized homogenous callus lines of (**a,b**) _Eryngium planum_, (**c**) _Plantago ovala_, (**d,e**) _Lychnis flos-cuculi_, (**f**) _Chenomenes japonica_ cultured under controlled conditions at Laboratory of Pharmaceutical Biology and Biotechnology, Collegium Pharmaceuticum, Poznan University of Medical Sciences. Stable cell suspension cultures can be generated when undifferentiated cells/calluses are propagated under a controlled liquid media environment. Biotechnological methods for the development of plant cell culture offer a renewable and environmentally sustainable alternative to extracting bioactive compounds [33]. The workflow for obtaining cell culture is presented in Figure 2.  
Until recently, cosmetic industries have been using extracts or compounds isolated from plants traditionally grown in the ground or harvested from various natural sites. However, the provision of fresh materials, regardless of the season and the plant reproductive cycle, has always been the source of limitations to their application in both the pharmaceutical and cosmetic industries, e.g., instability of cultivating some taxa, low metabolite content in the raw materials, and challenges associated with the extraction process [27]. Thus, the novel approach to producing quality-controlled anti-senescence plant-derived bioactive components--in vitro plant tissue and cell culture--will be perceived as a valid alternative. Callus development in plants is triggered by robust stimulation of the meristem, which hosts plant stem cells and serves as the primary origin of all plant tissues [34]. Not only are the products obtained using biotechnology methods reproducible, but they also meet the requirements of good manufacturing (GMP) and laboratory practices (GLPs). Standardized and controlled conditions allow the achievement of repeatable conditions, regardless of the geophysical properties, and avoid environmental contamination [27; 35; 36]. The development of plant cell cultures using biotechnology methods provides better quality secondary metabolite compounds, continuous production, higher production yield, and phytochemically uniform biomass [27; 37]. Some publications have reported in vitro plant systems producing secondary metabolites [38; 39; 40; 41], and these promising compounds are beneficial for skin health and aesthetics [42; 43; 44; 45; 46; 47].