Antioxidant, Antimicrobial, and Other Biological Properties of Pompia Juice

Abstract

Pompia is a Citrus species belonging to Sardinian endemic biodiversity. Health benefits were attributed to its flavedo rind extracts and essential oils while the juice qualities have never been investigated. In this paper, the antioxidant, antimicrobial, and other biological properties of Pompia juice were studied. A combined LCMS/electrochemical/biological approach was used to clarify a still debated phylogeny of this species and to explain the role of its juice phenolic compounds. A closer phylogenetic relationship with lemon and citron, rather than oranges was suggested. Sensors-based electrochemical measures, together with LCMS qualitative and quantitative analyses, revealed a high contribution of ascorbic acid and phenolics with low redox potential, isorhamnetin 3-O-rutinoside, diosmin, and diosmetin 6,8-diglucoside, to antioxidant capacity. The biological assays demonstrated a marked effect of low concentration of Pompia juice against reactive oxygen species (ROS) starting from 50 µg mL^-1, and a moderate capacity to reduce ROS damages on cell membrane. Treatments with Pompia juice also resulted in a significant reduction (20%) of the metabolic activity of SW48 colon cancer cells. Lastly, MIC, MBC, and MBIC antimicrobial assays demonstrated that Pompia and lemon juices have inhibitory and antibiofilm effects against the pathogenic bacteria Pseudomonas aeruginosa, Streptococcus aureus, and Enterococcus faecalis.

Keywords: Pompia juice; antimicrobial-antibiofilm activity; antioxidant activity; chemical characterization; colon cancer cells; phenolics.

Figure 1

Cyclic voltammetry, with a scanned potential range (E_app) comprised between –200 mV and +800 mV vs. carbon pseudoreference, in the absence (PBS black line) and in the presence of 4 mg mL⁻¹ of Pompia (green line) and lemon (yellow line) juices (A), and in the absence (PBS black line) and in the presence of 4 mg mL⁻¹ of Hamlin (yellow line), Sanguinello (orange line), and Moro (brown line) juices (B).

Figure 2

Evaluation of 2.5 mM TBH oxidative stress on differentiated CaCo-2 cell monolayer by determination of intracellular reactive oxygen species (ROS) production (A) and malonyldialdehyde (MDA) level (B), in the absence and in the presence of Pompia and other juices. * p ≤ 0.01 vs. TBH.

Figure 3

Effect of Pompia and lemon juices on metabolic activity of parental undifferentiated CaCo-2 (A) and SW48 (B) colon cancer cell lines. * = p ≤ 0.01 vs control.