Hesperidin-3'-o-methylether is more potent than hesperidin in phosphodiesterase inhibition and suppression of ovalbumin-induced airway hyperresponsiveness

Current Update on Role of Hesperidin in Inflammatory Lung Diseases: Chemistry, Pharmacology, and Drug Delivery Approaches

Inflammation is a common feature of many respiratory diseases, such as pneumonia, asthma, pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), lung cancer, acute lung injury, and COVID-19. Flavonoids have demonstrated their anti-inflammatory and antioxidant effects by influencing inflammation at different stages and majorly impacting several respiratory diseases’ onset and development. According to current studies, hesperidin, one of the most abundant polyphenols, can inhibit transcription factors or regulatory enzymes essential for controlling inflammation-linked mediators, including nuclear factor-kappa B (NF-κB), Inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). It also improved cellular antioxidant defences by activating the ERK/Nrf2 signalling pathway. Therefore, this review provides the latest studies on the effect of hesperidin in different respiratory diseases, its pharmacokinetic profile, and innovative drug delivery methods.

In vivo and in vitro Evaluation of the Protective Effects of Hesperidin in Lipopolysaccharide-Induced Inflammation and Cytotoxicity of Cell

(1) Background: Plant flavonoids are efficient in preventing and treating various diseases. This study aimed to evaluate the ability of hesperidin, a flavonoid found in citrus fruits, in inhibiting lipopolysaccharide (LPS) induced inflammation, which induced lethal toxicity in vivo, and to evaluate its importance as an antitumor agent in breast cancer. The in vivo experiments revealed the protective effects of hesperidin against the negative LPS effects on the liver and spleen of male mice. (2) Methods: In the liver, the antioxidant activity was measured by estimating the concentration of glutathione (GSH) and catalase (CAT), whereas in spleen, the concentration of cytokines including IL-33 and TNF-α was measured. The in vitro experiments including MTT assay, clonogenity test, and sulforhodamine 101 stain with DAPI (4', 6-diamidino-2-phenylindole) were used to assess the morphological apoptosis in breast cancer cells. (3) Results: The results of this study revealed a significant increase in the IL-33 and TNF-α cytokine levels in LPS challenged mice along with a considerable elevation in glutathione (GSH); moreover, the catalase (CAT) level was higher compared to that of the control group. Cytotoxicity of the MCF-7 cell line revealed significant differences among the groups treated with different concentrations when compared to the control groups, in a concentration-dependent manner. Hesperidin significantly inhibited the colony formation of MCF7 cells when compared to that of control. Clear changes were observed in the cell shape, including cell shrinkage and chromatin condensation, which were associated with a later apoptotic stage. (4) Conclusion: The results indicate that hesperidin might be a potential candidate in preventing diseases.

Dried Yeast Extracts Curtails Pulmonary Oxidative Stress, Inflammation and Tissue Destruction in a Model of Experimental Emphysema

Pulmonary emphysema is characterized by a loss of alveolar integrity due to prolonged cigarette smoking and inhaled irritants. Dried yeast extracts (YE) are employed as food additives, savory flavorings, or creation of umami taste sensations. Despite being rich in nutrition, their application as nutraceuticals and functional foods is not investigated much and little is known about the inhibition of pulmonary emphysema. This study examined whether YE ameliorated pulmonary emphysema in mice is evoked by cigarette smoke (CS) and ovalbumin (OVA). Mice were orally administrated with 25–100 mg/kg YE for 8 weeks. Alveolar epithelial A549 cells exposed to lipopolysaccharide or CS extracts (CSE) were supplemented with 10–100 µg/mL YE. Oral YE administration reduced bronchoalveolar lavage fluid leukocytosis in CS-/OVA-exposed mice. YE reduced induction of inflammatory mediators and MMP-12, and diminished reactive oxygen species production and emphysematous alterations in CS-challenged airways. The YE treatment blunted bax/bcl-2 ratio and activation of p53 and caspases in CS-exposed lungs. Apoptotic death was dampened in CSE-loaded YE-supplemented A549 cells. YE curtailed tissue levels of MMP-12 in inflammatory OVA-exposed lungs. YE abrogated the secretion of TNF-α and MCP-1 through blocking NF-κB signaling in endotoxin-loaded A549 cells. Thus, the antioxidant YE may therapeutically ameliorate oxidative stress and inflammatory tissue destruction in emphysematous diseases.

Hesperidin ameliorates bleomycin-induced experimental pulmonary fibrosis via inhibition of TGF-beta1/Smad3/AMPK and IkappaBalpha/NF-kappaB pathways

Bleomycin (BLM) is a chemotherapeutic agent which is associated with Idiopathic pulmonary fibrosis (IPF) due to its chronic administration. Hesperidin, a bioflavonoid has been reported to possess antioxidant, anti-inflammatory, wound healing, and antiapoptotic potential. To evaluate the therapeutic potential of hesperidin against BLM-induced pulmonary fibrosis and decipher its possible mechanism of action. Intraperitoneal administration of BLM (6 IU/kg) caused induction of IPF in Sprague-Dawley rats. Rats were treated with hesperidin (25, 50, and 100 mg/kg, p.o.) for 28 days, followed by estimation of various parameters in bronchoalveolar lavage fluid (BALF) and lung. Hesperidin (50 and 100 mg/kg) administration significantly ameliorated (p < 0.05) alterations induced by BLM in lung index, percent oxygen saturation, serum ALP and LDH levels, BALF differential cell count, and lung function test. Elevated levels of oxido-nitrosative stress, hydroxyproline, and myeloperoxidase levels in BALF and lung were significantly decreased by hesperidin on day 14. Hesperidin significantly inhibited BLM-induced down-regulated lung Nrf2 and HO-1 as well as up-regulated TNF-α, IL-1β, IL-6, collagen-1, TGF-β, and Smad-3 mRNA expressions. Western blot analysis showed that alteration in lung NF-κB, IκBα, AMPK, and PP2C-α protein expressions were ameliorated by hesperidin on day 28. Furthermore, BLM induced histological and ultrastructural aberrations in the lung which were attenuated by hesperidin treatment. Hesperidin alleviates BLM-induced IPF via inhibition of TGF-β1/Smad3/AMPK and IκBα/NF-κB pathways which in turn ameliorate the modulation of oxido-inflammatory markers (Nrf2 and HO-1) and pro-inflammatory markers (TNF-α, IL-1β, and IL-6) to reduce collagen deposition during pulmonary fibrosis. See also Figure 1(Fig. 1).

Inhibitory effects of hesperetin derivatives on guinea pig phosphodiesterases and their ratios between high- and low-affinity rolipram binding

The phosphodiesterase (PDE)4 molecule exists as two distinct conformers, PDE4H and PDE4L , which have high and low affinities, respectively, for the selective PDE4 inhibitor, rolipram. The inhibition of PDE4H and PDE4L is associated with adverse responses, such as nausea, vomiting, and gastric hypersecretion, and with anti-inflammatory and bronchodilator effects, respectively. We determined the therapeutic (PDE4H/PDE4L) ratios of hesperetin-7-O-methylether, hesperetin-5,7,3'-O-trimethylether (HTME), hesperetin-7-O-acetate, hesperetin-7,3'-O-diacetate, hesperetin-5,7,3'-O-triacetate (HTA), hesperetin-5,7,3'-O-tripropionate, hesperetin-5,7,3'-O-tributyrate, hesperetin-5,7,3'-O-triisobutyrate, and hesperetin-5,7,3'-O-tripivatate, and compared these ratios to those of hesperetin, hesperetin-7,3'-O-dimethylether, hesperidin, and hesperidin-3'-O-methylether to identify derivatives with therapeutic ratios and to characterize the structure-activity relationships among these compounds. The activities of PDE isozymes 1 through 5 were measured using a two-step procedure using [(3)H]adenosine 3',5'-cyclic monophosphate or [(3)H]guanosine 3',5'-cyclic monophosphate as substrates. The inhibitory concentration (IC50) for 50% of PDE4 inhibition and effective concentration (EC50) for replacing 50% of [(3)H]rolipram binding on high-affinity rolipram-binding sites was taken as the PDE4L and PDE4H value, respectively. The HTME and the HTA dually inhibited PDE3 and PDE4, and displayed PDE4H/PDE4L ratios of 18.3 and 20.8, respectively, suggesting that they may be candidate drugs for treating asthma and chronic obstructive pulmonary disease (COPD) because the combined inhibition of PDE3 and PDE4 has synergistically anti-inflammatory and bronchodilator effects in COPD patients.

Blockade of Airway Inflammation by Kaempferol via Disturbing Tyk-STAT Signaling in Airway Epithelial Cells and in Asthmatic Mice

Asthma is characterized by bronchial inflammation causing increased airway hyperresponsiveness and eosinophilia. The interaction between airway epithelium and inflammatory mediators plays a key role in the asthmatic pathogenesis. The in vitro study elucidated inhibitory effects of kaempferol, a flavonoid found in apples and many berries, on inflammation in human airway epithelial BEAS-2B cells. Nontoxic kaempferol at ≤20 μM suppressed the LPS-induced IL-8 production through the TLR4 activation, inhibiting eotaxin-1 induction. The in vivo study explored the demoting effects of kaempferol on asthmatic inflammation in BALB/c mice sensitized with ovalbumin (OVA). Mouse macrophage inflammatory protein-2 production and CXCR2 expression were upregulated in OVA-challenged mice, which was attenuated by oral administration of ≥10 mg/kg kaempferol. Kaempferol allayed the airway tissue levels of eotaxin-1 and eotaxin receptor CCR3 enhanced by OVA challenge. This study further explored the blockade of Tyk-STAT signaling by kaempferol in both LPS-stimulated BEAS-2B cells and OVA-challenged mice. LPS activated Tyk2 responsible for eotaxin-1 induction, while kaempferol dose-dependently inhibited LPS- or IL-8-inflamed Tyk2 activation. Similar inhibition of Tyk2 activation by kaempferol was observed in OVA-induced mice. Additionally, LPS stimulated the activation of STAT1/3 signaling concomitant with downregulated expression of Tyk-inhibiting SOCS3. In contrast, kaempferol encumbered STAT1/3 signaling with restoration of SOCS3 expression. Consistently, oral administration of kaempferol blocked STAT3 transactivation elevated by OVA challenge. These results demonstrate that kaempferol alleviated airway inflammation through modulating Tyk2-STAT1/3 signaling responsive to IL-8 in endotoxin-exposed airway epithelium and in asthmatic mice. Therefore, kaempferol may be a therapeutic agent targeting asthmatic diseases.