Diacetylcurcumin: Its Potential Antiarthritic Effect on a Freund's Complete Adjuvant-Induced Murine Model

Association of bisphosphonate with bone loss and pain-related behaviour in an adjuvant-induced osteoporosis model

OBJECTIVES

Osteoporosis animal models are used extensively to determine the mechanisms of disease pathology and identify potential biological targets. The study aimed to establish a bone loss model, identify pain-related behaviour in neighbouring joints using an adjuvant-induced osteoporosis model, and examine the therapeutic effect of bisphosphonates.

METHODS

Complete Freund's adjuvant was injected subcutaneously into the back of the right foot of 8-week-old female ddY mice. Subsequently, pain, arthritis, and bone density in the right knee were monitored over time.

RESULTS

Pain evaluation using von Frey filaments showed a significantly exacerbated knee pain threshold compared to the control group (saline administration) at 7- and 14-day intervals after complete Freund's adjuvant administration, and bone density during the same period also significantly declined. The adjuvant-induced osteoporosis model was created similarly; alendronate 40 μg/kg was subcutaneously injected twice and vehicle once from 7 to 14 days after onset. In the alendronate administration group on the 14th day, significant improvements in bone density, arthritis, and pain threshold around the knee were observed compared to the untreated group.

CONCLUSIONS

Alendronate may contribute to pain improvement through the simultaneous effects of bone mass improvement and suppression of osteoporotic pain.

Effect of Diacetylcurcumin Manganese Complex on Rotenone-Induced Oxidative Stress, Mitochondria Dysfunction, and Inflammation in the SH-SY5Y Parkinson's Disease Cell Model

Diacetylcurcumin manganese complex (DiAc-Cp-Mn) is a diacetylcurcumin (DiAc-Cp) derivative synthesized with Mn (II) to mimic superoxide dismutase (SOD). It exhibited superior reactive oxygen species (ROS) scavenging efficacy, particularly for the superoxide radical. The present study investigated the ROS scavenging activity, neuroprotective effects, and underlying mechanism of action of DiAc-Cp-Mn in a cellular model of Parkinson's disease. This study utilized rotenone-induced neurotoxicity in SH-SY5Y cells to assess the activities of DiAc-Cp-Mn by measuring cell viability, intracellular ROS, mitochondrial membrane potential (MMP), SOD, and catalase (CAT) activities. The mRNA expression of the nuclear factor erythroid 2 p45-related factor (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), inducible nitric oxide synthase (iNOS), and Interleukin 1β (IL-1β), which are oxidative and inflammatory genes, were also evaluated to clarify the molecular mechanism. The results of the in vitro assays showed that DiAc-Cp-Mn exhibited greater scavenging activity against superoxide radicals, hydrogen peroxide, and hydroxyl radicals compared to DiAc-Cp. In cell-based assays, DiAc-Cp-Mn demonstrated greater neuroprotective effects against rotenone-induced neurotoxicity when compared to its parent compound, DiAc-Cp. DiAc-Cp-Mn maintained MMP levels, reduced intracellular ROS levels, and increased the activities of SOD and CAT by activating the Nrf2-Keap1 signaling pathway. In addition, DiAc-Cp-Mn exerted its anti-inflammatory impact by down-regulating the mRNA expression of iNOS and IL-1β that provoked neuro-inflammation. The current study indicates that DiAc-Cp-Mn protects against rotenone-induced neuronal damage by reducing oxidative stress and inflammation.

Recent Advances in Understanding the Pathogenesis of Rheumatoid Arthritis: New Treatment Strategies

Rheumatoid arthritis (RA) is considered a chronic systemic, multi-factorial, inflammatory, and progressive autoimmune disease affecting many people worldwide. While patients show very individual courses of disease, with RA focusing on the musculoskeletal system, joints are often severely affected, leading to local inflammation, cartilage destruction, and bone erosion. To prevent joint damage and physical disability as one of many symptoms of RA, early diagnosis is critical. Auto-antibodies play a pivotal clinical role in patients with systemic RA. As biomarkers, they could help to make a more efficient diagnosis, prognosis, and treatment decision. Besides auto-antibodies, several other factors are involved in the progression of RA, such as epigenetic alterations, post-translational modifications, glycosylation, autophagy, and T-cells. Understanding the interplay between these factors would contribute to a deeper insight into the causes, mechanisms, progression, and treatment of the disease. In this review, the latest RA research findings are discussed to better understand the pathogenesis, and finally, treatment strategies for RA therapy are presented, including both conventional approaches and new methods that have been developed in recent years or are currently under investigation.

Curcumin and rheumatoid arthritis: A systematic review of literature

BACKGROUND

Curcumin is a natural polyphenol and the main compound from the rhizome of Turmeric (Curcuma longa) and other Curcuma species. It has been widely used for different medical purposes, such as improvement of pain and inflammatory conditions in various diseases.

PURPOSE

This systematic review was aimed to assess all studies regarding the efficacy of the pure form of curcumin (unformulated curcumin) on rheumatoid arthritis (RA).

METHODS

The comprehensive search of the literature was done until September 2020 on the MEDLINE, Embase, Scopus and Web of Knowledge databases. Out of 2079 initial records, 51 articles (13 in vitro and 37 animal and one human) were met our inclusion criteria.

RESULTS

Most studies have shown the curative effects of curcumin on clinical and inflammatory parameters of RA and reported different mechanisms; inhibition of mitogen-activated protein kinase family, extracellular signal-regulated protein kinase, activator protein-1 and nuclear factor kappa B are the main mechanisms associated with the anti-inflammatory function of curcumin in RA. The results of the only human study showed that curcumin significantly improved morning stiffness, walking time and joint swelling.

CONCLUSION

In conclusion, curcumin seems to be useful, and it is recommended that more human studies be performed to approve the cellular and animal results and determine the effective and optimal doses of curcumin on RA patients.

Non-Cytotoxic Dibenzyl and Difluoroborate Curcuminoid Fluorophores Allow Visualization of Nucleus or Cytoplasm in Bioimaging

Curcumin, the most important secondary metabolite isolated from Curcuma longa, is known for its numerous purported therapeutic properties and as a natural dye. Herein, based on curcumin's intrinsic fluorescence, a search for improved curcumin-based fluorophores was conducted. Within the set of semi-synthetic curcumin derivatives i.e. mono (1), di (2), tri (3), tetra (4) benzylated and dibenzyl-fluoroborate (5), the fluorescence properties of 2 and 5 in solution outstood with a two-fold quantum yield compared to curcumin. Furthermore, all benzylated derivatives showed a favorable minimal cytotoxic activity upon screening at 25 μM against human cancer and non-tumoral COS-7 cell lines, with a reduction of its cytotoxic effect related to the degree of substitution. Fluorophores 2 and 5 are versatile bioimaging tools, as revealed by Confocal Fluorescence Microscopy (CFM), and showed permeation of living cell membranes of astrocytes and astrocytomas. When 2 is excited with a 405- (blue) or 543-nm (green) laser, it is possible to exclusively and intensively visualize the nucleus. However, the fluorescence emission fades as the laser wavelength moves towards the red region. In comparison, 5 allows selective visualization of cytoplasm when a 560-nm laser is used, showing emission in the NIR region, while it is possible to exclusively observe the nucleus at the blue region with a 405-nm laser.

A short review on chemical properties, stability and nano-technological advances for curcumin delivery

Introduction: Curcumin is a polyphenol found in turmeric that is derived from the rhizomes of Curcuma longa. Curcumin has received a worldwide attention due to being a major constituent of the traditional Chinese and Indian holistic systems, and due to its well-documented pharmacological effects against various diseases.Areas covered: In order to provide a better understanding of curcumin's biological activities, its chemical, structural, spectral and photophysical properties should be studied. Also, it is crucial to study the aqueous, spectral, photophysical, photochemical, and thermal stability. Such studies indicated that curcumin suffers from bioavailability problems such as low serum levels, limited tissue distribution, and excessive metabolism which all limit its therapeutic efficacy. This review summarizes different properties of curcumin, its stability, bioavailability problems, and recent nanotechnological approaches with special highlight on nanocapsules for curcumin delivery.Expert opinion: Poor bioavailability of curcumin could be overcome through recently emerging and promising nanotechnological approaches.