Investigation into the Anti-Acne Effects of <i>Castanea sativa</i> Mill Leaf and Its Pure Ellagitannin Castalagin in HaCaT Cells Infected with <i>Cutibacterium acnes</i> oleh Stefano Piazza, Giulia Martinelli, Nicole Maranta, Carola Pozzoli, Marco Fumagalli, Vincenzo Nicolaci, Elisa Sonzogni, Luca Colombo, Enrico Sangiovanni, Mario Dell’Agli