Metabolism of Phenolic Compounds in LPS-stimulated Raw264.7 Cells Can Impact Their Anti-inflammatory efficacy: Indication of Hesperetin

Chiral Separation, Configuration Confirmation and Bioactivity Determination of the Stereoisomers of Hesperidin and Narirutin in Citrus reticulata Blanco

Hesperidin and narirutin are a class of flavanone glycosides, which are the main active constituents in Citrus reticulata Blanco. In the present study, a chiral HPLC-UV method with amylose tris(3,5-dimethylphenylcarbamate) as a stationary phase under a normal-phase mode was used to achieve the stereoselective separation of the C-2 diastereomers of hesperidin and narirutin simultaneously. The single epimer was then successfully prepared by applying semi-preparative chromatography, whose absolute configuration (R/S) was characterized by combining the experimental electronic circular dichroism (ECD) detection with time-dependent density functional theory (TDDFT) calculations. The epimer composition of these two chiral flavanone glycosides in Citrus reticulata Blanco was then determined, which was found to be slightly different in the herbs from different production regions. The anti-inflammatory activity of each prepared single epimer was further evaluated, and some differences between one pair of epimers of hesperidin and narirutin were observed, which suggested that the presence of different epimers should be considered in the quality evaluation and control of natural medicine.

Hesperetin, a Promising Treatment Option for Diabetes and Related Complications: A Literature Review

The morbidity and mortality of diabetes have increased dramatically in recent decades. Novel strategies for treating diabetes and its complications with minimal side effects are in urgent need. New monomeric molecules extracted from herbal medicine, which is a form of alternative medicine, are being sought as drug candidates for the treatment of diabetes and its complications. Hesperetin (Hst), a citrus flavonoid, is of increasing interest in scientific studies recently due to its properties in combating diabetes and its complications, whereas existing studies are scattered and unsystematic. Here, we summarized the literature studies over the last 10 years to review the potential therapeutic role of Hst in the prevention and mitigation of diabetes and its complications, intending to provide promising strategies for the clinical management of diabetes and its complications.

Anti-Inflammatory Activity of Mulberry Leaf Flavonoids In Vitro and In Vivo

Mulberry (Morus alba L.) is a flowering tree traditionally used in Chinese herbal medicine. Mulberry leaf flavonoids (MLFs) have been reported to exert important anti-inflammatory and antioxidant properties. The purpose of this study was to select the MLF with the best anti-inflammatory and antioxidative activities from MLFs eluted by different ethanol concentrations (30%, 50%, and 75%) and explore its pharmacological properties. Three types of MLFs inhibited the production of nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and inflammatory cytokines in lipopolysaccharide (LPS)-induced RAW 264.7 cells. All MLFs boosted the antioxidative capacity by decreasing the reactive oxygen species (ROS) production and the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and improving the metal ion chelating activity and reducing power. The results revealed that the MLFs eluted by 30% ethanol exhibited the best anti-inflammatory and antioxidative activities. A nontargeted metabolomic analysis was used to analyze 24 types of differential flavonoids between the MLFs. Quercetin, kaempferol, and their derivatives in 30%MLF were more abundant than the other two MLFs. Furthermore, we evaluated the pharmacological activities of 30%MLF in dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) mice. The 30%MLF could alleviate the clinical symptoms, reduce the secretion of inflammatory cytokines, and inhibit the activation of the inflammatory pathway in DSS-induced colitis mice. This study will provide valuable information for the development of MLFs eluted by 30% ethanol as a functional food.

Hesperetin inhibits KSHV reactivation and is reversed by HIF1α overexpression

Kaposi's sarcoma-associated herpesvirus (KSHV), an oncogenic virus, has two life cycle modes: the latent and lytic phases. KSHV lytic reactivation is important for both viral propagation and KSHV-induced tumorigenesis. The KSHV replication and transcription activator (RTA) protein is essential for lytic reactivation. Hesperetin, a citrus polyphenolic flavonoid, has antioxidant, anti-inflammatory, hypolipidemic, cardiovascular and anti-tumour effects. However, the effects of hesperetin on KSHV replication and KSHV-induced tumorigenesis have not yet been reported. Here, we report that hesperetin induces apoptotic cell death in BCBL-1 cells in a dose-dependent manner. Hesperetin inhibits KSHV reactivation and reduces the production of progeny virus from KSHV-harbouring cells. We also confirmed that HIF1α promotes the RTA transcriptional activities and lytic cycle-refractory state of KSHV-infected cells. Hesperetin suppresses HIF1α expression to inhibit KSHV lytic reactivation. These results suggest that hesperetin may represent a novel strategy for the treatment of KSHV infection and KSHV-associated lymphomas.

Thymus zygis subsp. zygis an Endemic Portuguese Plant: Phytochemical Profiling, Antioxidant, Anti-Proliferative and Anti-Inflammatory Activities

Thymus zygis subsp. zygis is an endemic Portuguese plant belonging to the Thymus zygis species. Although T. zygis is commonly used as a condiment and as a medicinal herb, a detailed description of the polyphenol composition of hydroethanolic (HE) and aqueous decoction (AD) extracts is not available. In this work, we describe for the first time a detailed phenolic composition of Thymus zygis subsp. zygis HE and AD extracts, together with their antioxidant, anti-proliferative and anti-inflammatory activities. Unlike other Thymus species, T. zygis subsp. zygis extracts contain higher amounts of luteolin-(?)-O-hexoside. However, the major phenolic compound is rosmarinic acid, and high amounts of salvianolic acids K and I were also detected. T. zygis subsp. zygis extracts exhibited significant scavenging activity of ABTS⁺, hydroxyl (^•OH), and nitric oxide (NO) radicals. Regarding the anti-proliferative/cytotoxic effect, tested against Caco-2 and HepG2 cells, the AD extract only slightly reduced cell viability at higher concentrations (IC₅₀ > 600 µg/mL, 48 h exposure), denoting very low toxicity, while the HE extract showed a high anti-proliferative effect, especially at 48 h exposure (IC₅₀ of 85.01 ± 15.10 μg/mL and 82.19 ± 2.46 μg/mL, for Caco-2 and HepG2, respectively). At non-cytotoxic concentrations, both extracts reduced the nitric oxide (NO) release by lipopolysaccharide (LPS)-stimulated RAW 264.7 cells (at 50 μg/mL, HE and AD extracts inhibited NO release in ~89% and 48%, respectively). In conclusion, the results highlight the non-toxic effect of aqueous extracts, both resembling the consumption of antioxidants in foodstuff or in functional food. Furthermore, the HE extract of T. zygis subsp. zygis is a source of promising molecules with antioxidant, anti-inflammatory and anticancer activities, highlighting its potential as a source of bioactive ingredients for nutraceutical and pharmaceutical industries.

Exploring the Anti-Acne Potential of Impepho [Helichrysum odoratissimum (L.) Sweet] to Combat Cutibacterium acnes Virulence

The Gram-positive bacterium Cutibacterium acnes (previously Propionibacterium acnes), plays an important role in the pathogenesis and progression of the dermatological skin disorder acne vulgaris. The methanolic extract of Helichrysum odoratissimum (L.) Sweet (HO-MeOH) was investigated for its ability to target bacterial growth and pathogenic virulence factors associated with acne progression. The gas chromatography-mass spectrometry (GC-MS) analysis of HO-MeOH identified α-humulene (3.94%), α-curcumene (3.74%), and caryophyllene (8.12%) as major constituents, which correlated with previous reports of other Helichrysum species. The HO-MeOH extract exhibited potent antimicrobial activity against C. acnes (ATCC 6919) with a minimum inhibitory concentration (MIC) of 7.81 µg/ml. It enhanced the antimicrobial activity of benzoyl peroxide (BPO). The extract showed high specificity against C. acnes cell aggregation at sub-inhibitory concentrations, preventing biofilm formation. Mature C. acnes biofilms were disrupted at a sub-inhibitory concentration of 3.91 µg/ml. At 100 µg/ml, HO-MeOH reduced interleukin-1α (IL-1α) cytokine levels in C. acnes-induced human keratinocytes (HaCaT) by 11.08%, highlighting its potential as a comedolytic agent for the treatment of comedonal acne. The extract exhibited a 50% inhibitory concentration (IC50) of 157.50 µg/ml against lipase enzyme activity, an enzyme responsible for sebum degradation, ultimately causing inflammation. The extract's anti-inflammatory activity was tested against various targets associated with inflammatory activation by the bacterium. The extract inhibited pro-inflammatory cytokine levels of IL-8 by 48.31% when compared to C. acnes-induced HaCaT cells at 7.81 µg/ml. It exhibited cyclooxygenase-II (COX-II) enzyme inhibition with an IC50 of 22.87 µg/ml. Intracellular nitric oxide (NO) was inhibited by 40.39% at 7.81 µg/ml when compared with NO production in lipopolysaccharide (LPS)-induced RAW264.7 cells. The intracellular NO inhibition was potentially due to the 2.14 fold reduction of inducible nitric oxide synthase (iNOS) gene expression. The HO-MeOH extract exhibited an IC50 of 145.45 µg/ml against virulent hyaluronidase enzyme activity, which is responsible for hyaluronan degradation and scar formation. This study provides scientific validation for the traditional use of H. odoratissimum as an ointment for pimples, not only due to its ability to control C. acnes proliferation but also due to its inhibitory activity on various targets associated with bacterial virulence leading to acne progression.

Design, Synthesis and Investigation of the Potential Anti-Inflammatory Activity of 7-O-Amide Hesperetin Derivatives

To develop new anti-inflammatory agents, a series of 7-O-amide hesperetin derivatives was designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. All compounds showed inhibitory effect on LPS-induced NO production. Among them, 7-O-(2-(Propylamino)-2-oxoethyl)hesperetin (4d) and 7-O-(2-(Cyclopentylamino)-2-oxoethyl)hesperetin (4k) with hydrophobic side chains exhibited the most potent NO inhibitory activity (IC₅₀ = 19.32 and 16.63 μM, respectively), showing stronger inhibitory effect on the production of pro- inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) than indomethacin and celecoxib at 10 μM. The structure-activity relationships (SARs) suggested that the 7-O-amide unit was buried in a medium-sized hydrophobic cavity of the bound receptor. Furthermore, compound 4d could also significantly suppress the expression of inducible nitric oxide synthase enzymes (iNOS) and cyclooxygenase-2 (COX-2), through the nuclear factor-kappa B (NF-κB) signaling pathway.

Antiproliferative Activity and Cell Metabolism of Hydroxycinnamic Acids in Human Colon Adenocarcinoma Cell Lines

In this study, we investigated the antiproliferative activity and the stability and metabolic fate of the main dietary hydroxycinnamates, using two colonic adenocarcinoma cell models (Caco-2 and SW480). Dihydrocaffeic and dihydroferulic acids were the most effective against cell proliferation in both cell lines with IC₅₀ values of 71.7 ± 1.1 and 83.1 ± 1.1 μmol/L, respectively ( P < 0.05) in Caco-2. At 200 μmol/L, caffeic and ferulic acids inhibited SW480 proliferation by 40.8 ± 1.6 and 59.9 ± 1.3%, respectively. Hydroxycinnamic acids with a catechol-type structure were degraded in Caco-2 cell medium, resulting in the production of H₂O₂. Intracellular Caco-2 UDP-glucuronosyltransferases and catechol- O-methyltransferases were able to form glucuronide and methyl conjugates. However, only the sulfate conjugates were detected after incubation with SW480. In addition, simple hydroxycinnamates were released from quinic and aspartic conjugates. The remarkable effect of dihydrocaffeic and dihydroferulic acids against cell proliferation is of paramount importance, since these compounds are the main metabolites detectable at the colonic level.

Intracellular Polyphenols: How Little We Know

In vitro cell studies are used by scientists to determine mechanisms that can be operating in vivo and pave the way for animal and human studies. Polyphenols, the major antioxidants in plants and the human diet, have been extensively studied in cells within thousands of publications. However, glucuronides, sulfates, and methyl metabolites and not the original polyphenols are generally present in the circulation and often have weaker beneficial effects in cell studies. The number of articles in the literature involving their cellular metabolites is quite small. We will critically examine the knowledge we have up to the present regarding polyphenols and cells in five areas: stability in in vitro cell culture media, metabolites, conjugation/deconjugation, transport to cells, and cells in vivo. Also, the future research needs in the field of polyphenols and their metabolites with cells will be outlined.

Cytisine-Pterocarpan-Derived Compounds: Biomimetic Synthesis and Apoptosis-Inducing Activity in Human Breast Cancer Cells

Cytisine-pterocarpan derived compounds were biomimetically synthesized with (-)-cytisine and (-)-maackiain via a N,N-4-dimethyl-4-aminopyridine (DMAP)-mediated synthetic strategy in a mild manner. In the present study, tonkinensine B (4) was elaborated in good and high yields with the optimized reaction conditions. The in vitro cytotoxicity of compound 4 was evaluated against breast cancer cell lines and showed that 4 had a better cytotoxicity against MDA-MB-231 cells (IC₅₀ = 19.2 μM). Depending on the research on cytotoxicities of 4 against RAW 264.7 and BV2 cells, it was suggested that 4 produced low cytotoxic effects on the central nervous system. Further study indicated that 4 demonstrated cytotoxic activity against MDA-MB-231 cells and the cytotoxic activity was induced by apoptosis. The results implied that the apoptosis might be induced by mitochondrion-mediated apoptosis via regulating the ratio of Bax/Bcl-2 and promoting the release of cytochrome c from the mitochondrion to the cytoplasm in MDA-MB-231 cells.