Exploring the pharmaceutical potential of Pistacia lentiscus L. acqueus extracts as a therapeutic agent against osteoarthritis manifestations: an in vitro study.

Ethnopharmacological relevance Pistacia lentiscus L. (PLL) is traditionally used in Sardinian folk medicine for osteoarthritis (OA) and represents a source of polyphenols with potential antioxidant and anti-inflammatory activity. Aim of the study To investigate the phenolic profile, the antioxidant potency, the total phenolic content, cytotoxicity, and anti-inflammatory properties of an aqueous leaf extract of PLL to explore its possible relevance in OA. Materials and methods Total phenolic content was assessed by the Folin–Ciocalteu spectrophotometric method. The polyphenols were also characterized by a High-Performance Liquid Chromatography (HPLC). The antioxidant ability was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH). The anti-inflammatory activity was examined through COX-1 and COX-2 inhibition while, the cytotoxicity was evaluated in dysplastic oral keratinocytes (DOK), human gingival fibroblasts (HGnF), and human periodontal ligament fibroblasts (HPLF) by using the WST-1 and the xCELLigence assays. Results The total phenolic content was 249.78 ± 37.10 mg GAE/g DW, where myricetin glycoside and catechin were the most abundant compounds. The DPPH scavenging capacity showed an IC 50 value 32.22 ± 6.43 μg/mL indicating considerable antioxidant potential of the extract. At 10 μg/mL the extract inhibited COX-1 and COX-2 by 92.07% and 71.04%, respectively, with IC 50 values of 5.14 μg/mL and 13.87 μg/mL. No relevant cytotoxicity was observed at lower concentrations in the tested cell lines. Conclusion PLL extract shows high total phenolic content, which together with the DPPH document strong antioxidant potency of the compound. This data together with the marked anti-inflammatory activity, and the limited cytotoxicity, support the potential interest of PLL extract as a natural candidate to counteract OA manifestations.