Vol.:(0123456789) 1 3 Photochemical & Photobiological Sciences https://doi.org/10.1007/s43630-022-00316-x ORIGINAL PAPERS Simple preparation of broadband UV flters based on TiO 2 coated with aqueous extracts of native trees from the Chaco region of Argentina Alba M. Loto 1  · Jesús M. N. Morales 1  · Ana B. Cisneros 1  · M. Sumampa Coria 1  · Fiorella Tulli 1  · Faustino E. Morán Vieyra 1,2  · Claudio D. Borsarelli 1,2 Received: 7 July 2022 / Accepted: 3 October 2022 © The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology 2022 Abstract The native forest of northwestern Argentina, as part of the Chaco region, is a rich and unexploited source of phytochemical compounds for medicinal/cosmetic applications. In the present study, fruit, leaf, branch, and bark organs of the native trees Sarcomphalus mistol (Mistol, M) and Schinopsis lorentzii (Quebracho Colorado santiagueño, QC) were harvested, and aqueous plant extracts (PE) were prepared. The spectroscopic (UV–Vis absorbance, difuse refectance, ATR-FTIR) and antioxidant (TEAC, Folin–Ciocalteu) properties of PE were characterized and used as TiO 2 coating material to obtain a series of TiO 2 @PE nanocomposites. These materials showed almost null photocatalytic activity compared to aqueous suspensions of bare TiO 2 , displaying yellowish to brownish coloration and high long-term stability in both freshwater and seawater model solutions. The loss of photocatalytic activity in TiO 2 @PE was associated with the combination of the internal flter efect and the antioxidant/radical capacity exerted by the phytochemicals of the PE coating, with higher broadband photoprotection for the nanocomposites prepared with QC extracts. Thus, this study shows the potential capacity of the forest resources of the Chaco region of Argentina for the development of new cosmetic and/or sun protection formulations. Graphical abstract Keywords Inorganic sunscreens · TiO 2 -based materials · Photoprotection · Phytochemicals · Native trees This publication is dedicated to Prof. Silvia E. Braslavsky, a pioneer in photobiology and photobiophysics, on the occasion of her 80th birthday. Extended author information available on the last page of the article