Essential Oil from Eucalyptus globulus (Labill.) Activates Complement Receptor-Mediated Phagocytosis and Stimulates Podosome Formation in Human Monocyte-Derived Macrophages

Abstract

Eucalyptus essential oil and its major constituent eucalyptol are extensively employed in the cosmetic, food, and pharmaceutical industries and their clinical use has recently expanded worldwide as an adjuvant in the treatment of infective and inflammatory diseases. We previously demonstrated that essential oil from Eucalyptus globulus (Labill.) (EO) stimulates in vitro the phagocytic activity of human monocyte-derived macrophages and counteracts the myelotoxicity induced by the chemotherapeutic 5-fluorouracil in immunocompetent rats. Here we characterize some mechanistic aspects underlying the immunostimulatory ability exerted by EO on macrophages. The internalization of fluorescent beads, fluorescent zymosan BioParticles, or apoptotic cancer cells was evaluated by confocal microscopy. Pro-inflammatory cytokine and chemokine release was determined by flow cytometry using the BD cytometric bead array. Receptor involvement in EO-stimulated phagocytosis was assessed using complement- or IgG-opsonized zymosan particles. The localization and expression of podosome components was analyzed by confocal microscopy and western blot. The main results demonstrated that: EO-induced activation of a macrophage is ascribable to its major component eucalyptol, as recently demonstrated for other cells of innate immunity; EO implements pathogen internalization and clearance by stimulating the complement receptor-mediated phagocytosis; EO stimulates podosome formation and increases the expression of podosome components. These results confirm that EO extract is a potent activator of innate cell-mediated immunity and thereby increase the scientific evidence supporting an additional property of this plant extract besides the known antiseptic and anti-inflammatory properties.

Emerging Insights into the Applicability of Essential Oils in the Management of Acne Vulgaris

“…The usage of Eucalyptus essential oil and its primary component, eucalyptol, in the food, cosmetic, and pharmaceutical sectors is considerable, and its clinical application as an adjuvant in the treatment of infectious and inflammatory illnesses has lately spread throughout the world [64].…”

How to Naturally Support the Immune System in Inflammation—Essential Oils as Immune Boosters

“…The principal role of the immune system is to protect the host from outside distress, e.g., pathogens. Its activity comprises two variants of systems: innate and adaptive immunity [ 2 ]. The innate immune system acts as the first line of response and is responsible for an adequate reaction to injury.…”

“…The mentioned essential oil might also increase podosome density as well as augment colocalization at the podosomes of the actin core with the ring component vinculin, thereby taking part in macrophage motility and chemotaxis processes. Moreover, in the initial stages of treatment, this essential oil is able to significantly stimulate expression levels of the basic structural elements of the podosome ring: αM (CD11b) and β2 (CD18) integrins, involved in control of the relation between cell and extracellular matrix in processes related to cell movement, and form together the heterodimeric complex CD11b/CD18 (or CR3) [ 2 ].…”

“… Eucalyptus plant (Myrtaceae) Its topical application inhibits edema and enhances vascular permeability in IgE-mediated allergic dermatitis it may stimulate the immune function of the respiratory tract, improves phagocytic activity of macrophages and it can be used as an adjuvant in some infections and inflammatory diseases. It increases podosome density and augments colocalization at the podosomes of the actin core with the ring component vinculin and—takes part in macrophage motility and chemotaxis processes The composition of essential oil from leaf of the plant Eucalyptus maculate/Eucalyptus globulus grown in Tanzania: α-Pinene 8.46/23.62 β-Myrcene 7.78/8.74 p-Cymene 10.10/10.00 Eucalyptol 54.29/51.62 γ-Terpinene 1.73/2.59 Terpinen-4-ol 0.04/2.74 [ 2 , 40 , 137 , 138 , 141 , 142 , 157 ] …”

Neutrophil Immunomodulatory Activity of Nerolidol, a Major Component of Essential Oils from Populus balsamifera Buds and Propolis

“…can modulate human neutrophil functions [ 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Moreover, essential oils and some of their compounds (e.g., monoterpenes, sesquiterpenes) are reported to modulate humoral and cellular immune responses [ 37 , 38 , 39 , 40 , 41 , 42 ]. Thus, we hypothesized that essential oils from P. balsamifera buds and propolis collected nearby might be a novel source of anti-inflammatory compounds.…”