Plant Stem Cells – A Magic Wand In Cosmetics?
What are PLANT STEM CELLS?
Plant stem cells are totally different from other cells due to their special properties: continuous multiplication (proliferation), transformation into other types of cells depending on the location of their representation in the plant (differentiation) and responsibility of helping damaged tissue to grow and repair.(1)
As observed in humans and animals, any kind of wound will stimulate tissue regeneration throughout the stem cells which will lead to organ repair. By contrast, in plants’ world, the regenerative actions are concentrated not only on fixing the damage but also on the development of a new plant.(2) Observing plant cellular and tissue level, the ability of regeneration is a unique and interesting process.(3)
What is the benefit to humans?
Dermatology researchers together with cosmetics industry are extremely interested in understanding the full mechanism of plant stem cells’ regulation on regeneration and how to extend the application of that cells to regeneration in human tissues.
In other words, scientists tackle the question whether eating an apple every day could have antiaging effect on our skin. Moreover, approach of using plants’ ingredients (“Organic” signs) in cosmetic product is very popular nowadays due to the safety and effectiveness with a longer shelf life.
Thus, year by year the plant stem cell topic has become more and more popular.
What are currently applications of plant stem cells?
There are plenty of positive cosmetic effects that can be obtained using plant stem cells, for example(1):
increasing the life of fibroblasts and stimulating their activity (e.g., Oryza sativa, Gardenia jasminoides);
rising the flexibility of the epidermis (e.g., Symphytum officinale, Capsicum annuum, Opuntia spp.);
managing cell division (e.g., Oryza sativa, Lotus japonicus);
fixing damaged epidermis (e.g., Panax ginsgen, Opuntia spp.);
activating DNA repair of the cells (e.g., Rubus ideaus, Lycopersicon esculentum);
protecting DNA from oxidative stress (e.g., Citrus limon);
keeping from harm of UV radiation (e.g., Dolichos biflorus, Opuntia ficus indica).
For a better comprehension, here are some very popular plants that we normally use and their properties from a cosmetic point of view:

Apple (Malus domestica): Reducing of wrinkles in the crow's feet area of the face.(5)

Tomato (Lycopersicon esculentum): Protecting skin from heavy metal toxicity.(6)

Ginger (Zingiber officinale): Improvement in skin structure by pore reduction and a mattifying effect revealed by a reduction of shininess and sebum.(7)
*all images are taken from Wikipedia
How it works?

Fig. 1 The process of using plant stem cells to obtain the needed compounds.(4)
The plant stem cells are located in root lateral meristems and shoot apical meristems. The initial step is to decide which part of the plant is in our interest (fruit, leaf or root). Then, we need to isolate stem cells by cutting the plant and putting it into agar plates. Cell growth takes place only in a liquid media. Then we need to extract the desired compounds by using oils or glycerol. Bioreactors are essential for a large-scale cell culturing because this process demands specific conditions (for instance, temperature, light etc.). (1)
But be aware that while a lot of cosmetic companies currently assert to use plant stem cells, they in fact utilize only extracts and not the live stem cells. Live cells seem to be more beneficial, hence, increasing a need for studying in delivery methods.
References:
(1) Miastkowska, M.; Sikora, E. Anti-Aging Properties of Plant Stem Cell Extracts. Cosmetics 2018, 5 (4). https://doi.org/10.3390/cosmetics5040055.
(2) Trehan, S.; Michniak-Kohn, B.; Beri, K. Plant Stem Cells in Cosmetics: Current Trends and Future Directions. Futur. Sci. OA 2017, 3 (4), FSO226. https://doi.org/10.4155/fsoa-2017-0026.
(3) https://www.learnskin.com/articles/plant-stem-cells-and-cosmetics (accessed on November 15, 2019)
(4) Warghat, A. R.; Thakur, K.; Sood, A. Plant Stem Cells: What We Know and What Is Anticipated. Mol. Biol. Rep. 2018, 45 (6), 2897–2905. https://doi.org/10.1007/s11033-018-4344-z.
(5) Schmid, D.; Blum, P.; Belser, E.; Zülli, F.; Schürch, C. Plant Stem Cell Extract for Longevity of Skin and Hair Plant Stem Cell Extract for Longevity. Int. J. Appl. Sci. 2008, 134 (5), 30–35.
(6) Barbulova, A.; Apone, F.; Colucci, G. Plant Cell Cultures as Source of Cosmetic Active Ingredients. Cosmetics 2014, 1 (2), 94–104. https://doi.org/10.3390/cosmetics1020094.
(7) https://www.naolys.com/media/refine_ginger_en.pdf (accessed on November 15, 2019)