What is "Centella Asiatica Leaf Cell Extract" and what is its utility?

The I.N.C.I. name "Centella Asiatica Leaf Cell Extract" refers to the aqueous extract of tiger grass leaves. According to legend, tigers used to roll in the Centella asiatica to heal their wounds, hence its nickname "tiger grass". Originating from Asia, this creeping and semi-aquatic herbaceous plant belongs to the family of Apiaceae. It primarily grows in the marshy areas of tropical or subtropical countries. Outside of Asia and Oceania, its cultivation is now widespread in certain African countries, such as Madagascar and South Africa. The medicinal properties of this plant have been recognised for over 2,000 years. It was used in the form of poultices to heal wounds, and more specifically the skin manifestations of leprosy.

In skincare and haircare, the Centella asiatica is used in the form of a cellular extract. This compound is derived from the cell culture in vitro of the plant's leaves in a nutrient medium composed of water, minerals, sugars, and vitamins, followed by elicitation, which involves stimulating the cell culture with UV and visible light to produce metabolites (active molecules). The extraction process continues with a rinsing stage to remove all traces of the nutrient medium, followed by filtration and sonication of the cells, and finally a dispersion of the obtained extract in vegetable glycerine.

The recommended dosage in a cosmetic formula is understood to be between 2 and 20%. There are no contraindications to the cosmetic use of Centella asiatica. Whether this ingredient is presented in powder form or as a vegetable oil, it can be used by pregnant women and young children.

When applied topically, thecellular extract of Centella asiatica offers numerous benefits:

• Combating oxidative stress:

  The phenolic compounds found in the leaves, roots, and petioles give the Centella asiatica its powerful antioxidant properties that protect the skin from free radicals. As a reminder, these are generated by several factors such as UVA rays, pollution, cigarette smoke, excessive alcohol consumption, stress... Highly reactive due to their instability caused by their unpaired electron, free radicals tend to react with the body's healthy molecules, damaging cells and tissues. This process, known as "oxidative stress", accelerates skin ageing and therefore the appearance of wrinkles and/or pigmentation spots. The phenolic compounds present in the Centella asiatica neutralise the action of free radicals by donating electrons to make these molecules stable and less reactive. Thus, this plant-based active ingredient delays skin ageing and protects the skin from external aggressions.

• Improving the appearance of closed superficial and shallow scars :

  The Centella asiatica is also known to help reshape the texture of marked skin (wounds, hypertrophic scars, burns, etc...). Indeed, triterpenic compounds (asiatic acid, madecassic acid, asiaticoside and madecassoside), the main components of Centella asiatica, have the ability to accelerate the skin regeneration process, marked by an increase in the proliferation of epithelial cells (epithelisation) and fibroblasts, by the induction of collagen synthesis in dermal fibroblastic cells, and by the ability to promote angiogenesis (formation of new vessels from a pre-existing network). Thus, the Centella asiatica can also be used in skincare to slow down the appearance of ageing signs, due to the strengthening of collagen, the quantity of which in the skin decreases with age.

• Reducing skin inflammation and soothing the skin:

  The Centella asiatica contains two active substances belonging to the saponoside family with recognised anti-inflammatory activity: the madecassoside and the asiaticoside. They have the ability to inhibit the activity of cyclooxygenase and lipoxygenase (two enzymes responsible for inflammatory reactions), and the inhibitory activity of pro-inflammatory cytokines. Thus, several studies have demonstrated the benefits of these active principles in reducing skin redness (stretch marks, erythematous marks linked for example to acne outbreaks or irritations, etc...), as well as their contribution to improving the skin's barrier function .

• Hydrating the skin:

  Several studies have demonstrated an increase in skin hydration levels following the daily application of a cosmetic formula based on Centella asiatica. Trans-epidermal water loss also decreased, indicating that the chemical substances present in this plant are humectants, meaning they retain water, like molecular sponges. Indeed, this is primarily linked to the presence in the triterpenic saponins of Centella asiatica of a hydrophilic sugar chain (glycone), mainly glucose and rhamnose, which have the ability to bind water molecules to the surface of the horny layer by forming an occlusive hydrophilic film, and can thus improve the function of the epidermal barrier. The triterpenoid components also have the ability to stimulate the synthesis of glycosaminoglycans, particularly hyaluronic acid. The skin stays hydrated for longer, preventing the appearance of fine dehydration lines and feelings of tightness due to skin dryness.

• Combating cellulite:

  A study has shown that an experiment conducted on a group of individuals suffering from cellulite revealed a beneficial effect of theGotu Kola extract when applied topically on theinhibition of cellulite progression, a non-inflammatory modification of the subcutaneous adipose tissue caused by an increase in the volume of fat cells, and a significant improvement in the skin condition, due to its lipolytic activity and through vascular stimulation.

• Protection against UV rays:

  A study has shown that the extract of Centella asiatica also exhibits a protective effect against UV rays at a high concentration (10%), which could be attributed to its antioxidant capacity and its triterpene components, but this remains low compared to the application of a broad-spectrum sun protection.

Here is a summary of the main actions of theplant extract of Centella asiatica on the hair and scalp:

• Stimulating hair growth and combating hair loss:

  Studies have reported that this plant-based active ingredient stimulates micro-circulation thereby promoting hair growth and giving it more strength and shine. In parallel, the madecassoside, a molecule found in the Centella asiatica, works deeply and stimulates blood vessels, limiting hair loss.

• Combatting dandruff and purifying the scalp:

  Thanks to its purifying and healing properties, the Centella asiatica soothes itchy scalps. Moreover, this plant has demonstrated an antifungal action against the Pityrosporum ovale (sometimes also called Malassezia furfur), the fungus responsible for scalp flaking causingdandruff.

• Protecting the hair from external aggressions (pollution, heat...):

  Its antioxidant properties protect the hair from the harmful effects of UV rays. These rays weaken the hydrolipidic film, leading to long-term keratin loss and drying of the hair fibre.

It is possible to find the Centella asiatica in certain skincare products intended for dull skin or in prevention of skin ageing, such as serums and creams. It also forms part of healing and repairing treatments to reduce the appearance of skin marks and/or stretch marks. It can also be found in certain shampoos and hair lotions.

At Typology, we have developed a anti-mark serum enriched with brightening and repairing actives, such as the gluconolactone from the family of polyhydroxy acids (PHA) and the extract of Centella asiatica. To fade acne scars, apply a drop locally to the affected areas, in the evening only.

• BOREL J. P. & al. Stimulation of collagen synthesis in venous and dermis fibroblast cultures by titrated extract from Centella asiatica. Connective Tissue Research (1990).

• ILHAM M. & al. Triterpene composition and bioactivities of Centella asiatica. Molecules (2011).

• BRZEZINSKA M. & al. Centella asiatica in cosmetology. Advances in Dermatology and Allergology/Postepy Dermatologii I Alergologii (2013).

• PUSHPENDRA KUMAR JAIN & al. Evaluating hair growth potential of some traditional herbs. Asian Journal of Pharmaceutical and Clinical Research (2015).

• PYTKOWSKA K. & al. Moisturizing and antiinflammatory properties of cosmetic formulations containing Centella asiatica extract. Indian Journal of Pharmaceutical Sciences (2016).

• SEUNGHEE BAE & al. Titrated extract of Centella asiatica increases hair inductive property through inhibition of STAT signaling pathway in three-dimensional spheroid cultured human dermal papilla cells. Bioscience, Biotechnology, and Biochemistry (2017).

• ZAKARIA Z. A. & al. Pharmacological properties of Centella asiatica hydrogel in accelerating wound healing in rabbits. BMC Complementary Medicine and Therapies (2019).

• AN J. H. & al. Inhibitory effect of Centella asiatica extract on DNCB-induced atopic dermatitis in HaCaT cells and BALB/c mice. Nutrients (2020).

• TONGHUA LIU & al. Therapeutic Potential of Centella asiatica and its triterpenes: A Review. Frontiers in Pharmacology (2020).