Recently, more and more researchers have begun to consider using waste bark fractions to
produce value-added biochemicals and materials, as well as for energy production. Extraction is often
the first operation in biomass biorefineries. Here we obtained hydroethanolic extracts from waste
cork and phloem fractions of Quercus cerris bark and analyzed them to determine their antioxidant,
antimicrobial, and nitric oxide (NO) production inhibition properties and their hepatotoxicity. The
antioxidant properties were investigated by ex vivo TBARSs as well as OxHLIA antioxidant assays,
the antibacterial properties against Gram-positive and Gram-negative bacteria isolated from food
and clinical sources, and antifungal properties against Aspergillus brasiliensis and A. fumigatus. The
NO production inhibition activity was assessed in a lipopolysaccharide (LPS)-stimulated murine
macrophage (RAW 264.7) cell line, and antiproliferative activities were determined against five
different cell lines, including lung (NCI-H460), gastric (AGS), breast (MCF7), and colon (CaCo2)
tumor cell lines, as well as a non-tumor cell line (PLP2). The hydroethanolic maceration of waste cork
and phloem yielded 4.4% and 2.4% extracts, respectively. Gallic acid glucosides, phenolic acids, and
ellagic acid were identified in both extracts. The waste cork and phloem extracts showed antioxidant,
antimicrobial, antifungal, and antiproliferative properties but also showed hepatotoxicity in the
case of waste cork. Both bark fractions varied in terms of their bioactivity, with waste cork extracts
showing, in general, higher bioactivity than phloem extracts.
