Comparison of free radical formation induced by baicalein and pentamethyl-hydroxychromane in human promyelocytic leukemia cells using electron spin resonance

The protective activity of natural flavonoids against osteoarthritis by targeting NF-κB signaling pathway

Osteoarthritis (OA) is a typical joint disease associated with chronic inflammation. The nuclear factor-kappaB (NF-κB) pathway plays an important role in inflammatory activity and inhibiting NF-κB-mediated inflammation can be a potential strategy for treating OA. Flavonoids are a class of naturally occurring polyphenols with anti-inflammatory properties. Structurally, natural flavonoids can be divided into several sub-groups, including flavonols, flavones, flavanols/catechins, flavanones, anthocyanins, and isoflavones. Increasing evidence demonstrates that natural flavonoids exhibit protective activity against the pathological changes of OA by inhibiting the NF-κB signaling pathway. Potentially, natural flavonoids may suppress NF-κB signaling-mediated inflammatory responses, ECM degradation, and chondrocyte apoptosis. The different biological actions of natural flavonoids against the NF-κB signaling pathway in OA chondrocytes might be associated with the differentially substituted groups on the structures. In this review, the efficacy and action mechanism of natural flavonoids against the development of OA are discussed by targeting the NF-κB signaling pathway. Potentially, flavonoids could become useful inhibitors of the NF-κB signaling pathway for the therapeutic management of OA.

Baicalein may act as a caloric restriction mimetic candidate to improve the anti-oxidant profile in a natural rodent model of aging

INTRODUCTION

Caloric restriction (CR) is the most effective intervention for extending the life span of vertebrate and invertebrate aging models.. CRMs, which are synthetic or natural chemicals that mimic the biochemical, hormonal, and physiological consequences of calorie restriction, are being researched for anti-aging benefits. Baicalein is a plant-derived polyphenol that has the potential of anti-oxidant, anti-inflammatory, and autophagy inducer. The objective of this study is to evaluate the anti-aging, anti-inflammatory, and antioxidant role of Baicalein in erythrocyte membrane and plasma, and evaluate the efficacy of Baicalein to act as a CRM candidate.

MATERIALS AND METHODS

The present study evaluates the effect of Baicalein on aging biomarkers in normal and aged rats. We study various pro- and anti-oxidant markers, erythrocyte membrane transporters, and eryptosis.

RESULTS

Baicalein supplementation in male Wistar rats significantly alleviated pro-oxidant markers and improved anti-oxidant profile. Improvement was also observed in age-induced alterations in membrane transporters, and eryptosis.

CONCLUSION

Based on the above observations we conclude that Baicalein has the potential to maintain extracellular ROS levels and redox homeostasis during the aging process, an effect which is similar to CR. Thus Baicalein may be a potent CRM candidate for anti-aging interventions.

Evaluation of the post-treatment anti-inflammatory capacity of osteoarthritic chondrocytes: An in vitro study using baicalein

INTRODUCTION

Targeting inflammatory cascades is considered a promising way to prevent knee osteoarthritis (OA) progression. In terms of down-regulating the expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-6, and matrix metalloproteinases (MMPs), pre-treatment with the flavonoid baicalein reportedly protects articular chondrocytes against the cytotoxicity of IL-1β. However, the benefits of post-treatment baicalein on osteoarthritic chondrocytes are not fully elucidated.

METHODS

In this study, primary human chondrocytes were stimulated with IL-1β prior to baicalein application to evaluate the therapeutic effect of post-treatment.

RESULTS

Post-treatment baicalein alleviated cell death and partially restored mitochondrial viability, while the senescence-associated secretory phenotype was not improved in IL-1β-stimulated chondrocytes. Post-treatment baicalein down-regulated the expressions of IL-1β, tumor necrosis factor-alpha, MMP-3, MMP-9, and MMP-13 mRNA as well as the protein production in stimulated cells. Even so, the levels of these factors were relative higher than those in un-treated chondrocytes. Moreover, iNOS, IL-6, IL-8, and COL1A1 expressions were consistently high, and IL-10 protein synthesis steadily increased in IL-1β-treated chondrocytes under baicalein treated status. Moreover, Western blot analyses showed that post-treatment baicalein suppressed nuclear factor kappa-light-chain-enhancer of activated B cells and p50 production while downstream cyclooxygenase-2 was still highly expressed.

CONCLUSION

Baicalein post-treatment to osteoarthritic chondrocytes had a minor benefit to the homeostasis of cartilaginous extracellular matrix.

Protective Mechanism of the Antioxidant Baicalein toward Hydroxyl Radical-Treated Bone Marrow-Derived Mesenchymal Stem Cells

Our study explores the antioxidant and cytoprotective effects of baicalein and further discusses the possible mechanisms. A methyl thiazolyl tetrazolium (MTT) assay revealed that baicalein could considerably enhance the viability of hydroxyl radical-treated bone marrow-mesenchymal stem cells (bmMSCs) at 37-370 µM. The highest viability rate was 120.4%. In subsequent studies, baicalein was observed to effectively scavenge hydroxyl radical and PTIO• radicals, reducing Fe³⁺ and Cu²⁺ ions. In the Fe²⁺-chelating UV-vis spectra, mixing of baicalein with Fe²⁺ yielded two evident redshifts (275 → 279 nm and 324 → 352 nm) and a broad absorption peak (λ_max ≈ 650 nm, ε = 1.6 × 10³ L mol^-1·cm^-1). Finally, we compared the Fe²⁺-chelating UV-vis spectra of baicalein and its analogues, including 5-hydroxyflavone, 6-hydroxyflavone, 7-hydroxyflavone, catechol, pyrogallol, and chrysin. This analysis revealed that the 4-keto group of the C-ring played a role. The 5,6,7-trihydroxy-group (pyrogallol group) in the A-ring served as an auxochrome, enhancing the absorbance of the UV-vis spectra and deepening the color of the Fe²⁺-complex. We concluded that baicalein, as an effective hydroxyl radical-scavenger, can protect bmMSCs from hydroxyl radical-mediated oxidative stress. Its hydroxyl radical-scavenging effects are likely exerted via two pathways: direct scavenging of hydroxyl radicals, possibly through electron transfer, and indirect inhibition of hydroxyl radical generation via Fe²⁺ chelation through the 4-keto-5,6,7-trihydroxy groups.

Physicochemical properties of Terminalia catappa seed oil as a novel dietary lipid source

Terminalia catappa Linn (TC) is an ornamental tree planted extensively in many countries. It has been known for a long time that the seeds are edible but no research has focused on the realm of its use as food. Our previous data showed that the seed contains high levels of oil content (600 g/kg) and possesses the optimum fatty acid balance indicated in fat dietary guidelines. This study aims to investigate the physical and chemical properties and the possibility of using TC seed oil as a new dietary lipid. The effects of extraction conditions, partial refining process, and storage stability on TC oil properties were conducted compared with soybean oil. The results showed that physicochemical properties including the density, refractive index, melting point, acidity, free fatty acid, saponification value, unsaponifiable, peroxide, and fatty acid composition of the extracted oil were comparable with soybean oil and their values followed the dietary standard of edible oil.