Influence of Artemisia annua L. on toll-like receptor expression in brain of mice infected with Acanthamoeba sp

Chemical constituents from artemisia annua with potential anti-inflammatory activities

Phytochemical analysis of Artemisia annua aerial parts revealed three novel lignan glycosides (arteannuoside A-B, annusesquilignanoside) and 18 known compounds (4-21), including spanning megastigmanes (4-13), coumarin (14), nitrogen-containing compound (15), phenylethanol glycoside (16), and phenolic compounds (17-21). Compounds (4, 6, 10, 12, 15-18) were first isolated from this species. Structural characterization employed NMR spectroscopy and literature comparison. The new compounds demonstrated concentration-dependent IL-6 inhibition in LPS-activated macrophages. At 100 μM, compounds 1 (68.75%), 2 (71.89%) and 3 (61.34%) showed strong activity, while at 50 μM yielded 33.45%, 39.37%, and 45.36% inhibition respectively.

Effectiveness of phytoproducts against pathogenic free-living amoebae - A scoping and critical review paving the way toward plant-based pharmaceuticals

Infections caused by free-living amoebae (FLA) have increased worldwide and are expected to worsen. The lack of drugs that are effective (especially against cysts), affordable, and safe to treat these infections exacerbates the concern. Plants present a promising source of bioactive compounds for developing effective drugs; however, the scientific literature on this topic has yet to be adequately synthesized. This work provides a critical scoping review summarizing the amoebicidal performance of plant-derived products and their potential for developing effective drugs to treat FLA infections. Out of 5889 articles retrieved from multiple databases, 119 articles were selected, from which data on 180 plant species belonging to 127 genera and 62 families were extracted. The extracts, essential oils, and compounds from these plants exhibited a diverse range of potency against cysts and trophozoites. Among the compounds studied, periglaucine A, kolavenic acid, and (+)-elatol are promising cysticidal drug candidates due to their high potency, as well as their known low toxicity to non-target cells. Tovophillin A, gartinin, 8-deoxygartinin, garcinone E, 9-hydroxycalabaxanthone, γ-mangostin, and borneol also exhibit high cysticidal potency, but their selectivity profile is unknown. Resveratrol, rosmarinic acid, β-amyrin, and vanillic acid stand out for their high potency against trophozoites and low toxicity to mammalian cells. Another group of compounds with similarly high trophocidal potency includes (-)-epicatechin, (-)-epigallocatechin, apigenin, costunolide, demethoxycurcumin, kaempferol, methyl-β-orcinolcarboxylate, sakuraetin, (+)-elatol, debromolaurinterol, luteolin, (-)-rogiolol, cystomexicone B, epigallocatechin gallate, quercetin, and α-bisabolol. These compounds are priority candidates for further studies on in vivo efficacy, safety, pharmacokinetics, and pharmacodynamics.

Dihydroartemisinin ameliorates innate inflammatory response induced by Streptococcussuis-derived muramidase-released protein via inactivation of TLR4-dependent NF-κB signaling

Muramidase-released protein (MRP) is now being recognized as a critical indicator of the virulence and pathogenicity of Streptococcus suis (S. suis). However, the identification of viable therapeutics for S. suis infection was hindered by the absence of an explicit mechanism for MRP-actuated inflammation. Dihydroartemisinin (DhA) is an artemisinin derivative with potential anti-inflammatory activity. The modulatory effect of DhA on the inflammatory response mediated by the virulence factor MRP remains obscure. This research aimed to identify the signaling mechanism by which MRP triggers the innate immune response in mouse spleen and cultured macrophages. With the candidate mechanism in mind, we investigated DhA for its ability to dampen the pro-inflammatory response induced by MRP. The innate immune response in mice was drastically triggered by MRP, manifesting as splenic and systemic inflammation with splenomegaly, immune cell infiltration, and an elevation in pro-inflammatory cytokines. A crucial role for Toll-like receptor 4 (TLR4) in coordinating the MRP-mediated inflammatory response via nuclear factor-kappa B (NF-κB) activation was revealed by TLR4 blockade. In addition, NF-κB-dependent transducer and activator of transcription 3 (STAT3) and mitogen-activated protein kinases (MAPKs) activation was required for the inflammatory signal transduction engendered by MRP. Intriguingly, we observed an alleviation effect of DhA on the MRP-induced immune response, which referred to the suppression of TLR4-mediated actuation of NF-κB-STAT3/MAPK cascades. The inflammatory response elicited by MRP is relevant to TLR4-dependent NF-κB activation, followed by an increase in the activity of STAT3 or MAPKs. DhA mitigates the inflammation process induced by MRP via blocking the TLR4 cascade, highlighting the therapeutic potential of DhA in targeting S. suis infection diseases.

Artemisia annua, a Traditional Plant Brought to Light

Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.

The modulatory effect of Artemisia annua L. on toll-like receptor expression in Acanthamoeba infected mouse lungs

The genus Acanthamoeba, which may cause different infections in humans, occurs widely in the environment. Lung inflammation caused by these parasites induces pulmonary pathological changes such as pulmonary necrosis, peribronchial plasma cell infiltration, moderate desquamation of alveolar cells and partial destruction of bronchial epithelial cells, and presence of numerous trophozoites and cysts among inflammatory cells. The aim of this study was to assess the influence of plant extracts from Artemisia annua L. on expression of the toll-like receptors TLR2 and TLR4 in lungs of mice with acanthamoebiasis. A. annua, which belongs to the family Asteraceae, is an annual plant that grows wild in Asia. In this study, statistically significant changes of expression of TLR2 and TLR4 were demonstrated. In the lungs of infected mice after application of extract from A. annua the expression of TLRs was observed mainly in bronchial epithelial cells, pneumocytes (to a lesser extent during the outbreak of infection), and in the course of high general TLR expression. TLR4 in particular was also visible in stromal cells of lung parenchyma. In conclusion, we confirmed that a plant extract of A. annua has a modulatory effect on components of the immune system such as TLR2 and TLR4.