Effects of some essential oils and saponins on lysozyme activity in human monocytes and epithelial cells

Lysozyme is one of the most important factors of innate immunity, possessing antibacterial, antiviral, antitumor and immune modulatory activities. Human lysozyme is produced by phagocytic cells and a variety of epithelial cells. In a recent study we have investigated the effect of some essential oils and saponins on the secretion and expression of lysozyme activity in the human monocytic cell line THP-1, and the human colonic epithelial cell line HT-29. The selection of these natural substances was based on their antibacterial, antiviral, anti-inflammatory or immune-stimulating properties. The influence on lysozyme secretion, as an important defense molecule of the human innate immune system, may provide a new mechanism which could explain these properties. Lysozyme activity was determined using highly sensitive fluorescence-based assay [1]. Some saponins from natural origin had stimulating effects on lysozyme activity secretion within one-hour-incubation in both monocytic and epithelial cells. Primulic acid, ginsenosid-Rd, quillaja and gypsophila saponins were proved to induce lysozyme activity secretion in both cell lines. Aescin could stimulate lysozyme activity secretion only in the monocytic cells, while it had no effect when incubated with the epithelial cells. Stimulating effect of essential oils on lysozyme activity in both monocytic and epithelial cell lines could be less frequently observed. Orange blossom oil had stimulating effect on lysozyme activity secretion in both cell lines. Inducing effect on lysozyme activity could also be detected by tea tree oil and majoran oil when incubated with the epithelial cells, whereas no effect or inhibitory effect was observed in the monocytic cells.

References: 1. Helal, R., Melzig, M.F. (2008) Pharmazie 63(6):415–419.