Naringenin, a flavonoid compound which exists abundantly in Citrus fruits, is proven to possess excellent antitussive and expectorant effects. However, the clinical applications of naringenin are restricted by its poor solubility and low local concentration by oral administration. The aim of the present study is to prepare a naringenin-hydroxypropyl-β-cyclodextrin (naringenin-HPβCD) inclusion as an inhalation solution for pulmonary delivery. The naringenin-HPβCD inclusion was characterized by phase solubility study, XRD, differential scanning calorimetry (DSC), proton nuclear magnetic resonance (¹HNMR), and two-dimensional rotating frame Overhauser effect spectroscopy (2D ROESY). The in vitro permeability of the inclusion was evaluated on Calu-3 cells and the pharmacokinetic profile of pulmonary delivery was investigated in Sprague-Dawley (SD) rats. Based on the linear model of phase solubility study, the relationship between naringenin and HPβCD was identified as A^L type with a 1:1 stoichiometry. XRD, DSC, and NMR studies indicated that the entire naringenin molecule is encapsulated into the cavity of HPβCD. HPβCD could increase the concentration of naringenin in the epithelium-lining fluid (ELF) of Calu-3 cells and act as a sustained release system for naringenin. The pharmacokinetic profile of naringenin-HPβCD inclusion showed rapid response and higher local concentration by pulmonary delivery. In conclusion, pulmonary delivery of naringenin-HPβCD inclusion is a promising formulation strategy, which could provide a new possibility for the clinical application of naringenin.

Naringenin, a natural flavonoid widely found in citrus fruits, has been reported to possess anti-oxidant, anti-inflammatory, and hepatoprotective properties as a natural dietary supplement. However, the regulatory mechanism of naringenin in human liver remains unclear. In the present study, messenger RNA sequencing (mRNA-seq), microRNA sequencing (miRNA-seq), and real-time qPCR were used to distinguish the expression differences between control and naringenin-treated HepaRG cells. We obtained 1037 differentially expressed mRNAs and 234 miRNAs. According to the target prediction and integration analysis in silico, we found 20 potential miRNA-mRNA pairs involved in liver metabolism. This study is the first to provide a perspective of miRNA–mRNA interactions in the regulation of naringenin via an integrated analysis of mRNA-seq and miRNA-seq in HepaRG cells, which further characterizes the nutraceutical value of naringenin as a food additive.

Naringenin is found mainly in citrus fruits, and is thought to be beneficial in the prevention and control of lung diseases. This study aims to investigate the mechanisms of naringenin against the damage in the lung caused by cigarette smoke. A system bioinformatic approach was proposed to predict the mechanisms of naringenin for protecting lung health. Then, we validated this prediction in BEAS-2B cells treated with cigarette smoke extract (CSE). System bioinformatic analysis indicated that naringenin exhibits protective effects on lung through the inhibition of inflammation and suppression of oxidative stress based on a multi-pathways network, mainly including oxidative stress pathway, Nrf2 pathway, Lung fibrosis pathway, IL-3 signaling pathway, and Aryl hydrocarbon receptor pathway. The in vitro results showed that naringenin significantly attenuated CSE-induced up-regulation of IL-8 and TNF-α. CSE stimulation increased the mRNA expressions of Nrf2, HO-1, and NQO1; the levels of total protein and nuclear protein of Nrf2; and the activity of SOD on days 2 and 4; but decreased these indexes on day 6. Naringenin can balance the antioxidant system by regulating Nrf2 and its downstream genes, preliminarily validating that Nrf2 pathway is involved in the protection offered by naringenin against cigarette smoke-induced damage to the lung. It suggests that dietary naringenin shows possible potential use in the management of lung health.

Background: Naringenin has demonstrated potential therapeutic effects against cigarette smoke-induced lung injury; however, its underlying mechanisms of regulating matrix metalloproteinase-9 (MMP-9) in alveolar macrophages remain unclear. Methods: The regulatory mechanisms of naringenin in cigarette smoke extract (CSE)-induced alveolar macrophages were investigated using proteomics, and then, naringenin’s targets were further validated by Western blot, molecular docking, molecular dynamics (MD) simulations, cellular thermal shift assay (CETSA), and enzyme activity assay. Results: The proteomics revealed that the PI3K/AKT signaling pathway might play a crucial role in naringenin’s inhibition of MMP-9. Western blot analysis confirmed that naringenin significantly inhibited CSE-upregulated PI3K/AKT signaling pathway and reduced MMP-9 expression in MH-S cells. Notably, the PI3K activator 740Y-P reversed naringenin’s effects on MMP-9. Additionally, molecular docking, MD simulations, and CETSA identified PI3K p85alpha as the potential binding site for naringenin, and naringenin markedly inhibited CSE-induced PI3K activity. In in vitro experiments, naringenin inhibiting MMP-9 secretion in alveolar macrophages contributed to alleviating elastin and E-cadherin damage in alveolar epithelial cells. Furthermore, naringenin effectively suppressed CSE-induced MMP-9 secretion in primary mouse alveolar macrophages and human THP-1-differentiated macrophages. Conclusions: Our findings revealed that naringenin, a potential candidate for treating smoking-induced lung injury, directly targeted PI3K p85alpha, inhibiting PI3K activity and MMP-9 expression in CSE-induced alveolar macrophages via suppressing the PI3K/AKT signaling pathway.