## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Nr**} & \multirow{2}{*}{**Identified Compound**} & \multirow{2}{*}{
\begin{tabular}{c} **Molecular** \\ **Formula** \\ \end{tabular} } & \multirow{2}{*}{**PubChem CID**} & \multirow{2}{*}{**CAS**} & \multirow{2}{*}{**Information**} & \multirow{2}{*}{**Ref.**} \\ \hline \multirow{4}{*}{32} & \multirow{4}{*}{Gly-Leu} & \multirow{4}{*}{C\({}_{8}\)H\({}_{\text{Hg}}\)N\({}_{2}\)O\({}_{3}\)} & \multirow{4}{*}{92843} & Not listed in the CosIng database, & & \\  & & & but in vitro and in vivo studies & & \\  & & & suggested that oral administration & & & \\  & & & of Gly-Leu improves skin & & & \\  & & & & hydration and elasticity in & \\  & & & & UVB-irradiated hairless mice. & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._-cream reduced both erythema and melanin indices significantly over the 8-week study period, indicating its potential anti-inflammatory and skin-brightening properties [72]. In addition, _Glycyrrhiza glabra_ (liquorice root) extract was reported to reduce erythema, pigmentation, and pH imbalances in skin, though the methodology was less instrumentally robust than others. The normalisation of skin pH toward slightly acidic levels is beneficial for maintaining enzymatic activity and microbiome homeostasis [73]. Anti-ageing properties of plant extracts have been substantiated by improvements in structural parameters such as wrinkle depth and elasticity. A study using olive leaf extract cream (SuperHeal(tm) OLIVE) revealed a significant reduction in wrinkle depth and TEWL, along with improvements in surface texture, as confirmed by Visioscan(r) imaging [74]. Likewise, extracts from _Pyrus pyrifolia_ callus culture--formulated in nanoliposomes--exhibited strong antioxidant and antiglycation activities, which are known to indirectly reduce wrinkle formation and structural degeneration in the dermis [75,76]. Callus- and suspension culture-derived extracts, such as those from _Citrus junos, Lavandula angustifolia, Crisium eriophorum,_ and _Leontopodium alipinum_, are gaining traction due to their reproducibility, scalability, and standardisation. They contain high levels of phenolics, flavonoids, and phytohormones like kinetin, which stimulate fibroblast activity and collagen synthesis. The study by [PERSON] et al. (2017) emphasised the antioxidant and wound-healing potential of _C. junos_ callus extract, reinforcing its dermal applications [77]. _C. eriophorum_ cell culture extract, which is abundant in phenol compounds, plays a role in regulating the essential markers for regulating sebum production and refining pore size [78]. Through in vitro and in vivo assays, [PERSON] et al. (2020) suggested that _L. alipinum_ callus culture extract could regulate genes for keratinisation and cornification, which could then induce skin barrier formation, making it a promising anti-ageing agent [79]. Plant stem cell technology used in cosme begins with the selection of a suitable plant species that exhibits unique longevity or regenerative properties [15]. For example, _Malus domestica_ (Swiss apple), _Vitis vinifera_ (grape), _Argania spinosa_ (argan tree), _Centella asatica, Leontopodium alipinum_ (edelweiss), _Lycium barbarum_ (Goi), and _Symphytum officinal_ (comfrey) are chosen for their high content of antioxidants, polyphenols, and protective secondary metabolites. All selected plant species demonstrate exceptional resistance to environmental stress factors such as UV radiation, extreme temperatures, dehydration, or oxidative damage. This natural resilience makes them ideal candidates for cosmetic applications aimed at protecting and revitalising human skin cells. The production of plant stem cell extracts for cosmetic use begins with the isolation and sterilisation of young plant tissue, which is cultured on nutrient media to induce the formation of the callus--a mass of pluripotent, undifferentiated cells.