Since their introduction to the cosmetics market, plant cells have been included in nearly 1000 unique products, with new product introductions growing at an average annual rate of 84% year-on-year (Mintel, 2013). Yet, their benefit for cosmetics goes far beyond a novel new label claim. Advances in biotechnology have ushered in a new generation of plant cell actives—ones with proven higher levels of desired molecules powerful enough to provide enhanced benefits, many with visible results. Until recently, plant cell ingredients held the promise of higher efficacy, yet failed to deliver the high levels of active molecules required for reproducible cosmetic benefits. This article explains how properly leveraging plant cell culture technology can maximize cosmetic efficacy through unprecedented access to nature’s best cosmetic actives.
Nature: The Ultimate Inventor
Plants contain a host of biologically active molecules known as secondary metabolites. These compounds, generated as defensive agents to protect the plant from external aggressors, have gained significant attention in academia and pharmacology as answers to human ailments. However, many of these desired metabolites have highly intricate structures either too difficult or economically unfeasible to chemically synthesize, leaving sourcing from nature as the only viable option.1 Access to these molecules has been mainly through extracts of naturally occurring or cultivated plants, and both pose limiting factors that can dramatically impact cosmetic efficacy. Variations in climate, growth elevations, and other environmental factors can significantly alter active levels in plants, and these differences have a direct impact on the level of cosmetic benefits that can be achieved with ingredients derived from them. In addition, the ecological impact of overuse of traditional means leads to other concerns. In the case of naturally occurring (wild-grown) plants, overharvesting can threaten biodiversity, while those plants obtained from commercial agriculture consume vast amounts of land and water resources. Both methods present long-term potential challenges to the ever-growing pursuit of eco-sustainability.
Plant cell culture presented an exciting alternative for accessing these valuable actives since, in theory, they could be utilized as “mini-factories” for the production of these molecules. Unfortunately, early introductions provided low yields due to inadequate knowledge of the biosynthesis pathways in which plants produce these compounds.2 Fortunately, more recent advances in plant cell biotechnology have led to the development of highly concentrated plant cell actives (referred to hereafter as “amplified plant cells”) demonstrating not only enhanced in-vitro activity but clinical evidence of substantial cosmetic efficacy.
Next Generation Plant Cells
The production of plant cells alone is not enough to guarantee a high presence of key plant molecules. Just as the same plant grown in different environments can show huge variances in active content, active levels obtained from cell culture can vary dramatically under different culture conditions. Figure 1 highlights these types of differences. Samples were taken from 17 different cell cultures made from the same starter plant (syringa vulgaris; common name: lilac). Differences in nutrient medium, growth rates and environmental conditions can all lead to reduced and inconsistent yields. Some cell culture conditions can reduce or even eliminate the presence of target molecules (Fig. 1a); other cultures can have large differences in active content with some cells containing higher levels of active molecules, while other cells in the same batch have significantly less, presenting huge batch-to-batch variations (Fig. 1b). Neither is desirable when trying to deliver the same level of cosmetic benefit from every jar of cream or lotion that your brand has promised. The desired outcome, in order to insure efficacy, is high and reproducible levels of target molecules, demonstrated by high and consistent active content (Fig. 1c) present in amplified plant cells.
The key to generating amplified plant cells that demonstrate consistently high levels of the most cosmetically beneficial actives is the understanding of exactly which environmental stimuli trigger the production of these specific molecules in plants. It is only through this understanding that a consistent presence of desired compounds can be reliably reproduced and guaranteed. Plant cells developed using this approach have far greater proven benefits than earlier plant cell introductions.1 Of utmost significance are the greater cosmetic benefits demonstrated by amplified plant cells. Also, the high elicitation of plant molecules has even allowed, in some cases, for the discovery of new bio-actives in what were thought to be well-known plants. Furthermore, the very small amounts of plant material required to initiate cell cultures now allows cosmetic formulators access to desired beneficial molecules from even rare and protected plant sources. Below are a few examples of the distinct benefits possible from these next generation actives.
Amplified Edelweiss Cells
Edelweiss (leontopodium alpinum), known as The Queen of the Mountain, is one of the most prized and famous plants of the European Alps. The rare plant grows spontaneously in the high mountains of Europe and the Himalayas. The unfortunate consequence of being such a desired plant is that it has been overharvested in its natural habitat and is now protected in many countries under classification as an endangered species.3 In addition to its physical beauty, Edelweiss is also a marvel to researchers for its content of leontopodic acid and other phenolic compounds that display high levels of anti-inflammatory and antioxidant activity.4
In addition to demonstrating the well-known anti-inflammatory and antioxidant activity of Edelweiss, in-vitro analysis of Amplified Edelweiss cell cultures showed almost complete protection of key skin structural proteins such as collagen and hyaluronic acid from degrading enzymes (98.65% and 80.2% protection, respectively, p<0.01 vs control). Further clinical analysis showed visible wrinkle reduction in as early as three weeks of use versus control (Fig. 2, p<0.001). This effect was not only measurable but also rated as highly perceivable, by the consumer panelists (Fig. 3).
Amplified Marrubium Cells
Environmental damage has been estimated to account for up to 90% of visible skin aging5 and recent research from a number of institutes including the American Academy of Dermatology have shown that UV filters alone do not provide absolute protection.6 Exposure to damaging elements such as UV, cigarette smoke, car exhaust fumes, and other pollutants can trigger the formation of destructive compounds known as Reactive Oxygen Species (ROS) on the skin. The skin possesses a multi-phase defense mechanism to block the destructive activity of these toxins; however, these defenses, though highly effective, can be overwhelmed by an onslaught of stressors.7 The most immediate phase of the body’s natural protection system is the skin’s myriad of natural antioxidants—such as vitamin E (tocopherol)—which are preferentially attacked by ROS and sacrificially depleted to protect the body. This activity is known as “free radical scavenging.” This protection is an immediate, but very short term, line of defense. ROS instantly form and attack cells and left unhindered, will react immediately with proteins, lipids and DNA and modify them.8 Antioxidants used in cosmetic formulations are incorporated to supplement this immediate protection; however, these additives are also quickly consumed.6
Longer-lasting protection comes from the highly protective activity of the body’s Phase II enzymes. This heightened level of defense is known as “detoxification.” This is the activation and response of defense enzymes that deactivate or “detoxify” ROS and other damaging molecules, breaking them down to non-harmful compounds.9 These detoxifying enzymes are present in low levels in the body but have very long-lasting effects. Where antioxidants have a one-to-one radical quenching activity (i.e. one antioxidant molecule terminates only one free radical molecule), these enzymes can remove hundreds, thousands, and even millions of ROS.
For example, one molecule of catalase, a well-known Phase II enzyme, can reduce more than 6 million molecules of hydrogen peroxide each minute!10 Activation of these Phase II enzymes normally happens in response to environmental aggression (i.e. oxidative stress), but certain plant molecules have been proven to “pre-activate” these enzymes so that they can be ready at the time of insult. Amplified Marrubium plant cells (developed from marrubium vulgare) have been shown to contain such beneficial molecules, and cosmetic studies with the cells show that they deliver both high free radical scavenging activity and pre-activate several Phase II defense enzymes. Thereby, Amplified Marrubium plant cells enhance the skin’s “natural protection factor” by maximizing the skin’s own self-defense system.
Amplified Centella Cells
Centella asiatica, also known as Gotu Kola or Tiger Grass, is a well-known herb used in traditional Ayurvedic, African and Chinese medicines for the treatment of skin diseases, wound healing, burns, varicose veins and ulcers.11 Clinical research with centella has focused primarily on asiaticoside, a widely studied triterpene derivative, that has been shown to increase collagen synthesis and has strong wound healing effects.12 However, asiaticoside on its own is a very modest antioxidant and not the strongest antioxidant molecule present in centella.11 Researchers at the Instituto di Ricerche Biotecnologiche (IRB), based in Italy, through their proprietary plant cell amplification method, discovered an untapped resource in centella with benefits beyond other well-known plant compounds. This molecule, 4-malonil-3,5-dicaffeoylquinic acid (known as irbic acid, now patented by IRB),13 has always existed in centella but its levels are so low that its presence is indiscernible among many other low level compounds existing in the plant.
Further testing of the molecule showed that irbic acid has very high collagen-protective activity and also significantly reduces the expression of nitric oxide, a capillary-degrading compound that is especially over-produced in rosacea sufferers, which leads to blood leakage from the capillaries and appears as red lines in the skin. This discovery further illustrates how the strategic use of plant culture can be a powerful tool for an industry seeking more sophisticated benefits from nature.
Amplified Echinacea Cells
Echinacea is among the most famous botanicals used in human treatment. In fact, echinacea species were the top selling medicinal botanicals in the 1990s and in particular, the wild-harvested Echinacea angustifolia roots held the highest market value of all echinacea sold as phytomedicine.14 The roots of the plant, which naturally grows in North America, were so prized that Echinacea angustifolia was at risk of becoming an endangered species in the late 1990s.15 To alleviate reliance on the wild grown variety, marketers moved to the lesser active Echinacea purpurea species or relied on cultivated sources of Echinacea angustifolia.
According to a study conducted by researchers at the University of Rome, attaining significant levels of echinacoside, the signature active molecule of echinacea, requires a three-year soil cultivation of Echinacea angustifolia before the roots can be collected.
Furthermore, to yield just 1 kilogram of echinacoside from agricultural cultivation requires more than 1,300 tons of water and over 11,000 square feet of land.16 Figure 4 illustrates the vast land and water resource conservation that can be achieved through the use of amplified plant cells for the delivery of the same level of echinacoside. To put that water consumption in more cosmetically relevant terms, using 1% of amplified Echinacea cells in a standard two ounce jar of cream, would save one ton of water annually with just six of those jars of cream! This is highly attractive considering the growing global efforts around water conservation. Plant cell culture as an alternative technology could yield a dramatic impact on water consumption for the cosmetic industry, which is substantially growing in its use of natural actives.
Advances in plant cell culture present an exciting opportunity for the discovery of new cosmetic benefits. Enhanced understanding of biological pathways that plants use to produce key compounds has led to the generation of a number of new actives with compelling cosmetic effects. These advances are breathing new life into cosmetic development and highlight the almost magical space where technology and nature align to drive enhanced benefits for cosmetics of the future.
- Kirakosyan, Ara and Kaufman, Peter B. The Use of Plant Cell Biotechnology for the Production of Phytochemicals. Recent Advances in Plant Biotechnology. s.l. : Springer Science, 2009, pp. 15-33.
- Oksman-Caldentey, Kirsi-Marja and Inze, Dirk. Plant cell dactories in the post-genomic era: new ways to produce designer secondary metabolites. 2004, TRENDS in Plant Science, pp. 432-440.
- The United States Library of Congress. Plant Protection in Selected Countries: Edelweiss. The Law Library of Congress. [Online] October 2012. http://www.loc.gov/law/help/edelweiss.php.
- Lulli, Daniela, et al., et al., Anti-inflammatory effects of concentrated ethanol extracts of Edelweiss (Leontopodium alpinum Cass.) Callus Cultures towards Human Keratinocytes and Endothelial Cells. 2012, Mediators of Inflammation, pp. 1-12.
- Farage, M.A., et al., et al., Intrinsic and extrinsic factors in skin ageing: a review. 2008, International Journal of Cosmetic Science, pp. 87-95.
- American Academy of Dermatology. American Academy of Dermatology News Releases. AAD website. [Online] August 4, 2011. http://www.aad.org/stories-and-news/news-releases/new-study-supports-recommendation-to-use-broad-spectrum-sunscreen-for-protection-against-skin-cancer-and-early-aging.
- Bickers, David R and Athar, Mohammad., Oxidative Stress in the Pathogenesis of Skin Disease. 2006, Journal of Investigative Dermatology, pp. 2565-2575.
- Sykiotis, Gerasimos P, et al., et al.,The role of the antioxidant and longevity - promoting Nrf2 pathway in metabolic regulation. 2011, Curr Opin Clin Nutr Metab Care, pp. 41-48.
- Masella, Roberta, et al., et al., Novel mechanisms of natural antioxidant compounds in biological systems: involvement of glutathione and glutathione-related enzymes. 2005, Journal of Nutritional Biochemistry, pp. 577-586.
- Haque, Rashidul, et al., et al., MicroRNA-30b-Mediated Regulation of Catalase Expression in Human ARPE-19 Cells. 2012, PLoS ONE, pp. 1-17.
- Hashim, Puziah, et al., et al., Triterpene Composition and Bioactivities of Centella asiatica. 2011, Molecules, pp. 1310-1322.
- Shukla, Arti, Rasik, Anamika M and Dhawan, Bhola N., Asiaticoside-induced elevation of antioxidant levels in healing wounds. 1999, Phytotherapy Research, pp. 50-54.
- Instituto di Ricerche Biotecnologiche. EP2133323 Italy, 2009.
- Binns, Shannon E, Arnason, John T and Baum, Bernard R., Phytochemical variation within populations of Echinacea angustifolia (Asteraceae). 2002, Biochemical systematics and ecology, pp. 837-854.
- Kindscher, Kelly, Price, Dana M and Castle, Lisa., Resprouting of Echinacea angustifolia augments sustainability of Wild Medicinal Plant Populations. 2008, Economic Botany, pp. 139-147.
- Nebbia, G. Agronomical trials on E. angustifolia, E. pallida, E. purpurea. Rome: International Water Culture Centre, 2004. Amplified Echinacea Cells Echinacea is among the most famous botanicals used in human treatmen