Triterpenes as Potential Drug Candidates for Rheumatoid Arthritis Treatment

UPLC/HR-ESI-MS/MS and GC/MS profiling of Eriobotrya japonica L. fruit in correlation to its antioxidant, anti-inflammatory, and anti-arthritic effects

Eriobotrya japonica Lindl. (Loquat) fruit is a subtropical edible fruit originally from China. It grows well in Egypt, but it is not widely known. In the current study, the fruit was extracted with 80% ethanol to get the total ethanol extract (TEE). A part of which was fractionated by dichloromethane to yield polar and nonpolar fractions (PF and NPF). The antioxidant and anti-inflammatory activities of the TEE were in vitro evaluated. The complete Freund's adjuvant (CFA) arthritis model was used to explore the in vivo biological assessment of the anti-arthritic properties in vivo of the TEE, PF, and NPF of the fruit. Additionally, the inspected limbs detached from all animals were subjected to histological inspection. Moreover, GC/MS analysis of the unsaponifiable (USF) and saponifiable (SF) fractions of the NPF was performed. Furthermore, 64 metabolites from various chemical classes were identified using UHPLC/HR-MS/MS analysis of the TEE of the fruit in both positive and negative ionization modes. The positive ionization mode of loquat fruit allowed for the first time the detection of two kinds of lyso-glycerophospholipids (Lyso-GPLs): lyso-glycerophosphoethanolamines (Lyso-PtdEtn) and lyso-glycerophosphocholines (Lyso-PtdCho). The fruit extracts exhibited a notable in vivo anti-arthritic activity by decreasing paw thickness in the treated rats and adjusting the inflammatory mediators. The TEE showed the highest anti-arthritic activity, followed by the PF that showed an observed activity, while the NPF exhibited the lowest activity. Histopathological findings showed a marked improvement in the arthritic condition of the excised limbs. Thus, E. japonica fruit may be considered as a promising natural antioxidant and anti-arthritic agent.

A Novel Dipterocarpol Derivative That Targets Alpha-Glucosidase and NLRP3 Inflammasome Activity for Treatment of Diabetes Mellitus

Type 2 diabetes mellitus is a chronic metabolic disorder characterized by persistent hyperglycemia, chronic inflammation, impaired insulin secretion, and/or peripheral insulin resistance. Current α-glucosidase inhibitors approved for clinical use exhibit limited efficacy compared to other glucose-lowering agents. In this study, a series of mono- and bis-benzylidene derivatives were synthesized via aldol condensation of 3-oxo-dammarane triterpenoids with terephthalic aldehyde. The target mono- and bis-benzylidene derivatives, based on the dammarane triterpenoids hollongdione 1, (20S)-23,24-epoxy-25,26,27-trinordammar-3,24-dione 2, and 24(R,S)-20(S)-epoxy-25-hydroxy-dammar-3-one 3, were successfully synthesized. Several of these inhibitors demonstrated significantly greater efficacy than the reference drug acarbose. Notably, compound 4 inhibited S. cerevisiae α-glucosidase with an IC50 of 2.67 μM. Furthermore, the target compounds effectively inhibited NLRP3 inflammasome activation, reducing IL-1β production in LPS+ATP-stimulated murine peritoneal macrophages without detectable cytotoxicity. Compound 8, which exhibited dual activity, was further characterized as an inhibitor of NLRP3 activation in peripheral blood mononuclear cells, leading to the prevention of pyroptosis and IL-1β release. Additionally, compound 8 was shown to promote neuronal survival in LPS+ATP-treated rat hippocampal slices, highlighting its potential as a promising antidiabetic agent that targets both postprandial hyperglycemia and metaflammation.

Exploring the osteogenic potential of semisynthetic triterpenes from Combretum leprosum: An in vitro and in silico study

Combretum leprosum Mart. is a plant of the Combretaceae family, widely distributed in the Northeast region of Brazil, popularly used as an anti-inflammatory agent, and rich in triterpenes. This study evaluated in vitro and in silico potential osteogenic of two semisynthetic triterpenes (CL-P2 and CL-P2A) obtained from the pentacyclic triterpene 3β,6β,16β-trihydroxylup-20(29)-ene (CL-1) isolated from C. leprosum. Assays were carried out in cultured murine osteoblasts (OFCOL II), first investigating the possible toxicity of the compounds on these cells through viability assays (MTT). Cell proliferation and activation were investigated by immunohistochemical evaluation of Ki-67, bone alkaline phosphatase (ALP) activity, and mineralization test by Von Kossa. Molecular docking analysis was performed to predict the binding affinity of CL-P2 and CL-P2A to target proteins involved in the regulation of osteogenesis, including: bone morphogenetic protein 2 (BMP-2), proteins related to Wingless-related integration (WNT) pathway (Low-density lipoprotein receptor-related protein 6-LRP6 and sclerostin-SOST), and receptor activator of nuclear factor (NF)-kB-ligand (RANK-L). Next, Western Blot and immunofluorescence investigated BMP-2, WNT, RANK-L, and OPG protein expressions in cultured murine osteoblasts (OFCOL II). None of the CL-P2 and CL-P2A concentrations were toxic to osteoblasts. Increased cell proliferation, ALP activity, and bone mineralization were observed. Molecular docking assays demonstrated interactions with BMP-2, LRP6, SOST, and RANK-L/OPG. There was observed increased expression of BMP-2, WNT, and RANK-L/OPG proteins. These results suggest, for the first time, the osteogenic potential of CL-P2 and CL-P2A.

The efficacy and safety of short-term and low-dose IL-2 combined with tocilizumab to treat rheumatoid arthritis

Background

Immunotherapy targeting factors related to immune imbalance has been widely employed for RA treatment. This study aimed to evaluate the efficacy and safety of low-dose interleukin (IL)-2 combined with tocilizumab (TCZ), a biologics targeting IL-6, in RA patients.

Methods

Fifty adults with active RA who met the criteria with complete clinical data were recruited, and divided into three groups: control group (n=15), IL-2 group (n=26), and IL-2+TCZ group (n=9). In addition to basic treatment, participants in the IL-2 group received IL-2 (0.5 MIU/day), while participants in the IL-2+TCZ group received IL-2 (0.5 MIU/day) along with one dose of TCZ (8 mg/kg, maximum dose: 800 mg). All subjects underwent condition assessment, laboratory indicators and safety indicators detection, and records before treatment and one week after treatment.

Results

Compared with the baseline, all three groups showed significant improvement in disease conditions, as evidenced by significantly reduced disease activity indicators. The low-dose IL-2 and combination treatment groups demonstrated a violent proliferation of Tregs, while the absolute number of Th1, Th2, and Th17 cells in the latter group showed a decreasing trend. The decrease in the Th17/Treg ratio was more pronounced in the IL-2+TCZ groups. No significant adverse reactions were observed in any of the patients.

Conclusion

Exogenous low doses of IL-2 combined TCZ were found to be safe and effective in reducing effector T cells and appropriately increasing Treg levels in RA patients with high effector T cell levels. This approach helps regulate immune homeostasis and contributes to the prevention of disease deterioration.

Clinical trial registration

https://www.chictr.org.cn/showprojEN.html?proj=13909, identifier ChiCTR-INR-16009546.

Comparative Phytoprofiling of Achillea millefolium Morphotypes: Assessing Antioxidant Activity, Phenolic and Triterpenic Compounds Variation across Different Plant Parts

Achillea millefolium L., commonly known as yarrow, is a versatile and widely distributed plant species with a rich history of ethnopharmacological significance. This study aimed to evaluate the comparative differences of A. millefolium inflorescence morphotypes. The phytochemical profile of white and pink inflorescence morphotypes was characterised by a complex of thirty-four phenolic and triterpene compounds. The species has distinct morphotypes of white and pink inflorescence. Phenolic and triterpenic profiles were determined, and individual compounds were quantified in inflorescence, leaf, and stem samples of two morphotypes tested. The antioxidant activity of plant extracts was evaluated by free radical scavenging (ABTS) and ferric-reducing antioxidant power (FRAP) assays. Caffeoylquinic acids predominated in all parts of the plant tested. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the principal compounds in the phenolic profile. Betulin, betulinic acid, and α-amyrin were the prevailing triterpenic components in the triterpenic profiles of Achillea millefolium morphotypes. The predominant flavonoids in inflorescences were flavones, while in leaves, flavonols were the organ-specific compounds. The quantitative differences were observed between plant parts of morphotypes. Leaves consistently displayed the highest amounts of identified compounds and have been testified as the main source of antioxidant activity. Overall, white inflorescences accumulated a higher total amount of compounds compared to pink ones. The observed differences between morphotypes derived from the same population reflect the differences in specialised metabolites and their chemotypes. This study addresses gaps in knowledge, particularly in phenolic and triterpenic profiling of coloured inflorescence morphotypes, enhancing our understanding of chemotypes and morphotypes within the species.

Triterpenes Drug Delivery Systems, a Modern Approach for Arthritis Targeted Therapy

Arthritis is a major cause of disability. Currently available anti-arthritic drugs, such as disease-modifying anti-rheumatic drugs (DMARDs), have serious side-effects associated with long-term use. Triterpenoids are natural products with known anti-inflammatory properties, and many have revealed efficiency against arthritis both in vitro and in vivo in several animal models, with negligible cytotoxicity. However, poor bioavailability due to low water solubility and extensive metabolism upon oral administration hinder the therapeutic use of anti-arthritic triterpenoids. Therefore, drug delivery systems (DDSs) able to improve the pharmacokinetic profile of triterpenoids and achieve sustained drug release are useful alternatives for targeted delivery in arthritis treatment. Several DDSs have been described in the literature for triterpenoid delivery, including microparticulate and nanoparticulate DDSs, such as polymeric micro and nanoparticles (NPs), polymeric micelles, liposomes, micro and nanoemulsions, and hydrogels. These systems have shown superior therapeutic effects in arthritis compared to the free drugs and are similar to currently available anti-arthritic drugs without significant side-effects. This review focuses on nanocarriers for triterpenoid delivery in arthritis therapy, including osteoarthritis (OA), rheumatoid arthritis (RA) and gout that appeared in the literature in the last ten years.