The Bio-Patina on a Hypogeum Wall of the Matera-Sassi Rupestrian Church "San Pietro Barisano" before and after Treatment with Glycoalkaloids.

The investigation focused on the deterioration of the walls in the hypogeum of "San Pietro Barisano" rupestrian church, located in the Matera-Sassi (Southern Italy), one of the UNESCO World Heritage sites. The study evaluated the biocide activity of a mixture of natural glycoalkaloids (GAs) extracted from the unripe fruit of and applied to clean a hypogeum wall surface in the church affected by bio-patinas. The analyzed bio-patina, collected before treatment and, at pre-established times, after treatment, showed changes in chemical composition detected by XPS, accompanied by visible discoloration and biological activity variation.