Carcinogenic effect of low doses of polycyclic and heterocyclic aromatic hydrocarbons and amines and lack of protection by inulin supplementation.

Evidence suggests that meat processing and heat treatment may increase cancer risk through exposure to potentially carcinogenic compounds, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic aromatic amines (HAAs). This study aims to investigate the effect of low concentrations of PAHs and HAAs (from 1 to 100 µmol/L/24h and 48h) in colorectal tumor cells (HT-29, HCT116, and LS174T) and to evaluate the effect of PAHs in the presence of inulin in mice. In vitro, the 4-PAHs have no effect on healthy colon cells but decreased the viability of the colorectal tumor cells and activated the mRNA and protein expressions of CYP1A1 and CYP1B1. In vivo, in mice with colitis induced by 3% DSS, the 4-PAHs (equimolar mix at 50,100, 150 mg/kg.bw, orally 3 times a week for 3 weeks) induced a loss of body weight and tumor formation. Inulin (10 g/L) had no effect on colon length and tumor formation. A significant decrease in the loss of b.w was observed in inulin group as compared to the fiber free group. These results underscore the importance of considering the biological association between low-dose exposure to 4-HAPs and diet-related colon tumors.

Anti-inflammatory activity of essential oils from Tunisian aromatic and medicinal plants and their major constituents in THP-1 macrophages.

In this study, the capacity of eight essential oils (EOs), sage (Salvia officinalis), coriander (Coriandrum sativum), rosemary (Rosmarinus officinalis), black cumin (Nigella sativa), prickly juniper (Juniperus oxycedrus), geranium (Pelargonium graveolens), oregano (Origanum vulgare) and wormwood (Artemisia herba-alba), on the inhibition of NF-κB activation was screened at concentrations up to 0.25 µL/mL using THP-1 human macrophages bearing a NF-κB reporter. This screening selected coriander, geranium, and wormwood EOs as the most active, which later evidenced the ability to decrease over 50 % IL-6, IL-1ß, TNF-α and COX-2 mRNA expression in LPS-stimulated THP-1 macrophages. The chemical composition of selected EOs was performed by gas chromatography-mass spectrometry (GC-MS). The two major constituents (>50 % of each EO) were tested at the same concentrations presented in each EO. It was demonstrated that the major compound or the binary mixtures of the two major compounds could explain the anti-inflammatory effects reported for the crude EOs. Additionally, the selected EOs also inhibit>50 % caspase-1 activity. However, this effect could not be attributed to the major components (except for ß-citronellol/geranium oil, 40 %/65 % caspase-1 inhibition), suggesting, in addition to potential synergistic effects, the presence of minor compounds with caspase-1 inhibitory activity. These results demonstrated the potential use of the EOs obtained from Tunisian flora as valuable sources of anti-inflammatory agents providing beneficial health effects by reducing the levels of inflammatory mediators involved in the genesis of several diseases.