Sinapic acid ameliorates airway inflammation in murine ovalbumin-induced allergic asthma by reducing Th2 cytokine production

Lipid mediators obtained from docosahexaenoic acid by soybean lipoxygenase alleviate ovalbumin‑induced allergic asthma in mice by reducing airway inflammation and oxidative stress

Asthma is a chronic allergic respiratory disease lacking effective therapies. The present study investigated the anti‑asthmatic properties of lipid mediators using an ovalbumin (OVA)‑induced allergic asthma model. Lipid mediators (LM; 17S‑monohydroxy docosahexaenoic acid, resolvin D5 and protectin DX at a ratio of 3:47:50) were derived from docosahexaenoic acid through soybean lipoxygenase. LM treatment significantly alleviated major features of allergic asthma, including inflammatory cell infiltration, with a particular reduction in eosinophils in bronchoalveolar lavage fluid, downregulation of Th2 cytokine expression, attenuation of airway remodeling, and oxidative stress, thereby closely resembling the normal condition. Additionally, a significant increase in the serum levels of interleukin‑6 [167.12±6.25 pg/ml; P<0.0001 vs. negative control (NC) group], tumor necrosis factor‑α (109.17±7.17 pg/ml; P<0.0001 vs. NC group) and IgE (90.24±5.98 ng/ml; P<0.0001 vs. NC group) was observed following OVA challenge; however, oral administration of LM resulted in a notable reduction in these levels to 99.45±6.12 pg/ml (P<0.001 vs. OVA group), 62.51±4.03 pg/ml (P<0.001 vs. OVA group) and 56.50±2.70 ng/ml (P<0.001 vs. OVA group), respectively. Furthermore, the heightened expression of Th2‑related cytokines induced by OVA was observed to be restored closely to normal conditions following LM treatment, as demonstrated for both gene and protein expression levels. Histological analysis demonstrated that LM mitigated inflammatory cell infiltration while reducing mucus secretion. Additionally, LM effectively ameliorated oxidative stress in OVA‑induced asthma, with a significant increase in the activity of superoxide dismutase (~185% vs. OVA group; P<0.001), elevated levels of glutathione (~74% higher than the OVA group; P<0.001) and reduced content of malondialdehyde (~40% lower than the OVA group; P<0.001) in lung tissues. Collectively, these findings suggested that LM effectively protected lung tissues from inflammation and oxidative stress, thereby representing a promising therapeutic option for the treatment of allergic asthma.

Aerosol inhalation of inflammatory cells-targeted dendrimer-dexamethasone conjugate for efficient allergic asthma therapy

Allergic asthma (AA) is a common breathing disorder clinically characterized by the high occurrence of acute and continuous inflammation. However, the current treatment options for AA are lacking in effectiveness and diversity. In this study, we determined that the cell membrane receptor of gamma-glutamyl transferase (GGT) was highly overexpressed on the inflammatory cells that infiltrate the pulmonary tissues in AA cases. Therefore, we developed a GGT-specific dendrimer-dexamethasone conjugate (GSHDDC) that could be administered via aerosol inhalation to treat AA in a rapid and sustained manner. The GSHDDC was fabricated by the covalent attachment of 6-hydroxyhexyl acrylate-modified dexamethasone to polyamidoamine dendrimers via a carbonic ester linkage and the amino Michael addition, followed by the surface modification of the dendrimers with the GGT substrate of glutathione. After aerosol inhalation by the AA mice, the small particle-sized GSHDDC could easily diffuse into pulmonary alveoli and touch with the inflammatory cells via the glutathione ligand/GGT receptor-mediated recognition. The overexpressed GGT on the surface of inflammatory cells then triggers the gamma-glutamyl transfer reactions of glutathione to generate positively charged primary amines, thereby inducing rapid cationization-mediated cellular endocytosis into the inflammatory cells. The dexamethasone was gradually released by the intracellular enzyme hydrolysis, enabling sustained anti-inflammatory effects (e.g., reducing eosinophil infiltration, decreasing the levels of inflammatory factors) in the ovalbumin-induced AA mice. This study demonstrates the effectiveness of an inhalational and active inflammatory cells-targeted dendrimer-dexamethasone conjugate for efficient AA therapy.

Therapeutic Potential of Phenolic Compounds in Medicinal Plants-Natural Health Products for Human Health

Phenolic compounds and flavonoids are potential substitutes for bioactive agents in pharmaceutical and medicinal sections to promote human health and prevent and cure different diseases. The most common flavonoids found in nature are anthocyanins, flavones, flavanones, flavonols, flavanonols, isoflavones, and other sub-classes. The impacts of plant flavonoids and other phenolics on human health promoting and diseases curing and preventing are antioxidant effects, antibacterial impacts, cardioprotective effects, anticancer impacts, immune system promoting, anti-inflammatory effects, and skin protective effects from UV radiation. This work aims to provide an overview of phenolic compounds and flavonoids as potential and important sources of pharmaceutical and medical application according to recently published studies, as well as some interesting directions for future research. The keyword searches for flavonoids, phenolics, isoflavones, tannins, coumarins, lignans, quinones, xanthones, curcuminoids, stilbenes, cucurmin, phenylethanoids, and secoiridoids medicinal plant were performed by using Web of Science, Scopus, Google scholar, and PubMed. Phenolic acids contain a carboxylic acid group in addition to the basic phenolic structure and are mainly divided into hydroxybenzoic and hydroxycinnamic acids. Hydroxybenzoic acids are based on a C6-C1 skeleton and are often found bound to small organic acids, glycosyl moieties, or cell structural components. Common hydroxybenzoic acids include gallic, syringic, protocatechuic, p-hydroxybenzoic, vanillic, gentistic, and salicylic acids. Hydroxycinnamic acids are based on a C6-C3 skeleton and are also often bound to other molecules such as quinic acid and glucose. The main hydroxycinnamic acids are caffeic, p-coumaric, ferulic, and sinapic acids.