By Anna Huang
Snail slime is currently a skincare ingredient which is revolutionising the cosmetics and skincare industry (Ellijimi et al., 2018). The slime which snails secrete from their salivary epidermal glands located in the snail’s foot (pedal glands) is also known as snail mucin and covers the entire external surface of the animal (Trapella et al., 2018). For the mollusc, the mucus has adhesive, emollient, moisturizing, lubricating, protective and even reparative properties. For humans, the mixture of active substances found in snail mucin are thought to help treat a variety of skin disorders due to its variety of properties (e.g. antimicrobial, skin regenerative etc.) (Nguyen et al., 2020; Trapella et al., 2018).
The secretions of the molluscs Achatina fulica (African giant land snail) and Cornu aspersum (formerly Helix aspersa and Cryptomphalus aspersa, or common brown garden snail) are commonly found in some innovative skincare products for their beneficial dermatologic properties (Nguyen et al., 2020).
Snail mucin has been found to contain antibacterial chemicals, such as glycosaminoglycans and glycosylated proteins, which can facilitate wound healing and repair by preventing bacterial infections (Etim et al., 2016). The mucus of several snail types has been shown to have inhibitory and bactericidal potency against Staphylococcus
sp., Streptococcus sp. and Pseudomonas sp. isolated from wounds (Etim et al., 2016). Achacin in particular, a bactericidal glycoprotein in the mucus of the African giant snail (Achatina fulica), can kill both gram-positive and gram-negative bacteria in their growing states by attacking the cytoplasm (Hisako Otsuka-Fuchino et al., 1992). Thus, if more adequate exploration is carried out, the mucus of these snails could become useful sources for antibacterial agents that can be used in wound treatment.
The mucin of Cornu aspersum (MCA) is also famous in cosmeceuticals for its skin regenerative properties, that stem from its molecular properties which induce cellular regeneration (Brieva et al., 2008).
The ability of human skin to rejuvenate itself and the remodelling ability of the extracellular matrix (ECM) deteriorates with time. Skin aging compromises the remodelling ability of the ECM as dermal fibroblasts are less proficient at proliferation and migrating to sites of injured tissue in order to manipulate the ECM and promote skin healing (Brieva et al., 2008; Iglesias-de la Cruz, M. C et al., 2012). To stimulate skin regeneration, MCA has been found to increase cell proliferation (further enhanced by adding citrate) which in turn promotes fibroblast (cells which synthesise the ECM and collagen) proliferation and survival (Brieva et al., 2008). Cell proliferation is incredibly important for wound healing as scar formation relies not only on cell migration, but also on replenishing the skin tissue which provides the migrating cells (Brieva et al., 2008).
In addition to its proliferative activity, MCA has shown to increase ECM assembly, which is vital in wound repair since matrix remodelling is also important for fibroblast motility (Brieva et al., 2008).
Moreover, MCA is a popular skincare ingredient for its anti-aging properties (Fabi et al., 2013). Antioxidant activity and free radical scavenging capability of MCA can help repair and prevent ultraviolet induced photoaging inflicted by an increased production of reactive oxygen species (ROS) which causes photo-oxidative damage and decreases cell proliferation as well as migration (Brieva et al., 2008; Iglesias-de la Cruz, M. C et al., 2012; Nguyen et al., 2020). MCA possesses both superoxide dismutase (SOD) and glutathione s-transferase (GST) antioxidant activities (Brieva et al., 2008). SOD is an important enzyme for the inactivation of superoxide anion (O2–) radicals and hydrogen peroxide (H2O2) and can also act to sequester free radicals. In contrast, GST is a typical phase 2 enzyme (enzymes catalysing the conjugation reactions) responsible for detoxification of both ROS and electrophilic xenobiotics (Addor, 2019; Brieva et al., 2008). All in all, MCA displays multiple methods of antioxidant action, at the level of free radical production and through sequestering free radicals.
More recently, research has shown that MCA also exhibits antimelanogenic and antitumoral effects against melanoma cells. MCA can inhibit melanin content and decrease tyrosinase activity (to limit the production of melanin) in melanoma cells (Ellijimi et al., 2018). However, more research needs to be carried out so that the specific molecules which are behind the anti-tumour effect of MCA can be identified and purified. Still, snail slime could prove to be useful in the future as a tumour proliferation or metastasis inhibitor.
Addor, F. A. S. (2019) Topical effects of SCA® (Cryptomphalus aspersa secretion) associated with regenerative and antioxidant ingredients on aged skin: evaluation by confocal and clinical microscopy. Clinical, Cosmetic and Investigational Dermatology. 12 133-140. Available from: https://search.datacite.org/works/10.2147/ccid.s191153. Available from: doi: 10.2147/ccid.s191153.
Brieva, A., Philips, N., Tejedor, R., Guerrero, A., Pivel, J. P., Alonso-Lebrero, J. L. & Gonzalez, S. (2008) Molecular Basis for the Regenerative Properties of a Secretion of the Mollusk Cryptomphalus aspersa. Skin Pharmacology and Physiology. 21 (1), 15-22. Available from: https://search.datacite.org/works/10.1159/000109084. Available from: doi: 10.1159/000109084.
Ellijimi, C., Hammouda, M. B., Othman, H., Moslah, W., Jebali, J., Mabrouk, H. B., Morjen, M., Haoues, M., Luis, J., Marrakchi, N., Essafi-Benkhadir, K. & Srairi-Abid, N. (2018) Helix aspersa maxima mucus exhibits antimelanogenic and antitumorale ﬀects against melanoma cells. Biomedicine & Pharmacotherapy. 101 871-880.
Etim, L., Aleruchi, C. & Obande, G. (2016) Antibacterial Properties of Snail Mucus on Bacteria Isolated from Patients with Wound Infection. British Microbiology Research Journal. 11 (2), 1-9. Available from: doi: 10.9734/BMRJ/2016/21731.
Fabi, S. G., Cohen, J. L., Peterson, J. D., Kiripolsky, M. G. & Goldman, M. P. (2013) The Effects of Filtrate of the Secretion of the Cryptomphalus aspersa on Photoaged Skin
. Journal of Drugs in Dermatology. 12 (4), .
Hisako Otsuka-Fuchino, Yoichi Watanabe, Chikako Hirakawa, Toru Tamiya, Matsumoto, J. J. & Takahide Tsuchiya. (1992) Bactericidal action of a glycoprotein from the body surface mucus of giant African snail. Comparative Biochemistry and Physiology. C, Comparative Pharmacology. 101 (3), 607-613. Available from: http://dx.doi.org/10.1016/0742-8413(92)90094-N. Available from: doi: 10.1016/0742-8413(92)90094-N.
Iglesias-de la Cruz, M. C, Sanz-Rodríguez, F., Zamarrón, A., Reyes, E., Carrasco, E., González, S. & Juarranz, A. (2012) A secretion of the mollusc Cryptomphalus aspersa promotes proliferation, migration and survival of keratinocytes and dermal fibroblasts in vitro. International Journal of Cosmetic Science. 34 (2), 183-189. Available from: https://search.datacite.org/works/10.1111/j.1468-2494.2011.00699.x. Available from: doi: 10.1111/j.1468-2494.2011.00699.x.
Nguyen, J. K., Masub, N. & Jagdeo, J. (2020) Bioactive ingredients in Korean cosmeceuticals: Trends and research evidence. Journal of Cosmetic Dermatology. 19 (7), 1555-1569. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1111/jocd.13344. Available from: doi: 10.1111/jocd.13344.
Trapella, C., Rizzo, R., Gallo, S., Alogna, A., Bortolotti, D., Casciano, F., Zauli, G., Secchiero, P. & Voltan, R. (2018) HelixComplex snail mucus exhibits pro-survival, proliferative and pro-migration effects on mammalian fibroblasts. Scientific Reports. 8 (1), 17665. Available from: https://search.datacite.org/works/10.1038/s41598-018-35816-3. Available from: doi: 10.1038/s41598-018-35816-3.