Biologia | Ambiente


Davide Giacometti, 2002 | Promontogno, GR


Plant extracts, or natural antioxidants, are often added to sunscreens as they are considered to increase their efficacy. This experiment focuses on the potential photoprotective action of Castanea sativa fruit extract and the mechanisms by which this possible action occurs, using an in vivo method based on the survivability of UV-sensitive yeast cells upon exposure to UV radiation. The data obtained show that the compounds with antioxidant activity of chestnut fruit extract protect the yeast cells from damage induced by UVR. The addition of substances such as chestnut extract by various sunscreen manufacturers to their products is therefore justified and not just a marketing strategy.


Nowadays, there is a worldwide trend to develop high UV protection sunscreens using low concentrations of convention sunscreen chemicals. Naturally occurring compounds have gained considerable attention as protective agents because of their broad biological activities, such as UV absorption, antioxidant, and anti-inflammatory actions. This experiment aims at verifying whether compounds with antioxidant activity (AOA) of chestnut extract have any photoprotective potential and how these compounds act in boosting the UV filter system in a sunscreen.


The experiment was conducted by preparing UV-sensitive yeast cultures and experimentally determining the optimal exposure times and concentrations of chestnut fruit extract to collect the data as accurately as possible. Contact between the extract and the yeast cells was made either directly, by spreading it on the cultures, or indirectly, by mixing it with a sun filter taken as a reference. This procedure made it possible to determine both the photoprotective efficacy of the components of the extract and the mechanism by which they act.


The data obtained show a clear improvement in UV protection when chestnut extract, with its antioxidant components, is placed directly in contact with yeast cultures. Without direct contact, there is no improvement in photoprotective capacity.


The addition of substances that contain compounds with antioxidant activity, like those of chestnut extract, to sun-care products increases the photoprotective characteristics of the sunscreen formulation. These natural substances act by their antioxidant activity and not by chemical/physical filtering properties.


The addition of chestnut extract to sun-care products, and consequently the addition of extracts with a similar composition, increases the photoprotective characteristics of the sunscreen formulation. The addition of substances similar to chestnut extract with AOA by various sunscreen manufacturers is justified. A potential future development of this study could be to analyse the efficacy of extracts of other plant components, the use of other extraction solvents, or the combination with other types of sunscreens.



Valutazione del lavoro espressa dall’esperta

Alice Giani

Effettivi benefici o solo marketing? Davide Giacometti, incuriosito da un prodotto cosmetico la cui composizione è strettamente legata al suo territorio natio, indaga in modo personalizzato ed originale la capacità di un estratto dicastagno di aumentare l’efficacia di un prodotto solare. Riadattando al contesto un noto metodo di ricerca in vivo ed integrando i dati con un’ampia ricerca bibliografica, il candidato stabilisce se e come alcuni estratti botanici mostrano efficacia fotoprotettiva, discutendo in modo critico i risultati ottenuti e proponendo strategie per ulteriori ricerche.






Bündner Kantonsschule, Chur
Docente: MSc Stefano Peduzzi