The Behavior of Certain Coumarins and Furocoumarins Toward Sulfur Reagents

Chemical profiling and anti-inflammatory effect of phenolic extract of Gentiana rigescens Franch

ETHNOPHARMACOLOGICAL RELEVANCE

Gentiana rigescens Franch. (G. rigescens), known as "Dian Long Dan" in Southern Yunnan Herbal, has a long history in traditional Chinese medicine for treating hepatitis, allergies, postherpetic neuralgia, cholecystitis and rheumatism.

AIM OF THE STUDY

This study aims to comprehensively analyze the phenolic composition of G. rigescens, evaluate its potential anti-inflammatory effects, elucidate underlying mechanisms, and identify its in vivo bioactive phenolic constituents.

MATERIALS AND METHODS

The extraction of G. rigescens phenolic compounds (GRP) was optimized using the Box-Behnken response surface method, with four phenolic compounds (mangiferin, esculetin, ferulic acid and kaempferol) used as quality index markers. GRP's phytochemical composition was subsequently profiled via UPLC-Q-TOF-MS/MS analysis. Anti-inflammatory activity and mechanisms were assessed in LPS-stimulated RAW264.7 cells and murine models, utilizing NO production assays, ELISA, qRT-PCR, Western blotting and histopathological analysis. Bioactive phenolic compounds in blood were identified post-oral administration for in vivo activity prediction.

RESULTS

The optimal extraction conditions for GRP were determined as follows: Soxhlet extraction using acetone with hydrochloric acid 0.06 mol/L, at a liquid-to-solid ratio of 132: l. for 6.6 h. Seventy-one of phenolic compounds were identified in GRP using UPLC-Q-TOF-MS/MS. GRP significantly inhibited LPS-induced NO production in RAW 264.7 macrophages and reduced pro-inflammatory cytokines IL-6, IL-1β, and TNF-α while increasing anti-inflammatory IL-10. In the carrageenan-induced inflammatory model, GRP exhibited a 69.81% inhibition rate of toe swelling at high doses (1 g/kg), along with protective effects against joint injury, as observed in histological assessments. Mechanistically, GRP downregulated mRNA levels of inflammatory cytokines and reduced the expression of inflammatory proteins iNOS, COX-2, p65, p-p65 and P-IκB as shown by Western blotting. Twenty-five of phenolic compounds, including mangiferin, swertianolin, acacetin, umbelliferone and caffeic acid, were identified in vivo in the blood, indicating potential bioactive roles.

CONCLUSIONS

This study provides the first comprehensive profile of the phenolic composition of G. rigescen, alongside a detailed investigation of its anti-inflammatory activity, mechanisms, and in vivo bioactive components. These findings highlight the therapeutic potential of Dian Long Dan's phenolic constituents and support further research on G. rigescens.

Farnesyl pyrophosphate synthase inhibitors with antiosteoporosis efficacy in ovariectomized rats: A mixed binding approach beyond bisphosphonates

The primary focus of bisphosphonate medications is on targeting human farnesyl pyrophosphate synthase (hFPPS), an essential regulator of mammalian isoprenoids. Yet, these drugs encounter limitations due to their restricted "druglike" properties and their effectiveness primarily in treating skeletal disorders. In this study, we synthesized novel non-bisphosphonate compounds, using 4,4'-(ethane-1,2-diylbis(oxy))bis(3-methoxybenzaldehyde) (1) as a starting compound, with the aim of targeting hFPPS through a mixed binding approach. Among the various compounds tested, compounds 4a and 4b exhibited significant inhibition of hFPPS activity, with IC50 values of 1.108 and 1.24 μM, respectively. Docking studies further revealed that both compounds bound within the allylic binding site and near the isopentenyl diphosphate (IPP) site within the hFPPS pocket. Molecular dynamic simulations were performed on the best docking pose of the most potent compound 4a to confirm the formation of a stable complex with hFPPS. In an in vivo study conducted on ovariectomized rats, various biochemical markers including osteocalcin, estradiol, osteoprotegerin, bone mineral content, and density were negatively impacted, while levels of bone specific alkaline phosphatase, receptor activator of nuclear factor kappa-Β ligand, serum/urinary calcium, and phosphate increased. Notably, compound 4a exhibited antiresorptive properties similar to zoledronate, effectively restoring most of the perturbed biochemical estimations. These findings suggest the potential of compound 4a, a non-bisphosphonate compound, as alternative therapeutic agents for combating osteoporosis.

Synthesis, molecular docking and biological evaluation of 2-(thiophen-2-yl)-1H-indoles as potent HIV-1 non-nucleoside reverse transcriptase inhibitors

New 2-(thiophen-2-yl)-1H-indole derivatives bearing hydrophobic substituents at the 3-position were designed, synthesized and evaluated for their inhibition of HIV-1 reverse transcriptase (RT) enzyme. Dialkylphosphites (2a-c) or trialkylphosphites (3a-c) were reacted with 2-(thiophen-2-yl)-1H-indole-3-carbaldehyde (1) yielding the corresponding α-hydroxyphosphonate adducts (7a-7c). The reaction of compound 1 with the ylidenetriphenylphosphoranes (4a-4c) proceeds via Wittig mechanism giving the corresponding ethylenes (E, 8a-c). Compounds 8b,c were equally obtained upon reacting aldehyde 1 with the appropriate dialkylphosphonates 5a,b under the Horner-Wittig reaction conditions. On the other hand, the reaction of aldehyde 1 with diethyl cyanomethylene phosphonate (5c) yielded a mixture of the E-ethylene 10 and the cyanovinyl phosphonate 11. The thioaldehyde 12 was obtained upon refluxing aldehyde 1 with the Lawesson's reagent (LR, 6a) or with the Japanese reagent (JR, 6b) in dry toluene. Upon evaluation of HIV-1 Reverse Transcriptase enzyme inhibition, compound 8b (IC₅₀ = 2.93 nM) exhibited the superior HIV-1 RT inhibition and its potency was about 3-folds that of Efavirenz (IC₅₀ = 6.03 nM). Also, compounds 9a (IC₅₀ = 4.09 nM) and 12 (IC₅₀ = 3.54 nM) showed significantly higher inhibition potency. Moreover, compounds 7b (IC₅₀ = 7.48 nM), and 8a (IC₅₀ = 4.55 nM) showed potency not significantly different from that of Efavirenz. Molecular docking experiments on these potent compounds was in accordance with the in vitro data and confirmed binding of these compounds to the enzyme through ring-stacking and hydrogen bond interactions. According to these results, the new molecules would serve as potent HIV-1 NNRTIs inhibitors.

Synthesis, structure-activity relationships (SAR) and in silico studies of coumarin derivatives with antifungal activity

The increased incidence of opportunistic fungal infections, associated with greater resistance to the antifungal drugs currently in use has highlighted the need for new solutions. In this study twenty four coumarin derivatives were screened in vitro for antifungal activity against strains of Aspergillus. Some of the compounds exhibited significant antifungal activity with MICs values ranging between 16 and 32 µg/mL. The structure-activity relationships (SAR) study demonstrated that O-substitutions are essential for antifungal activity. It also showed that the presence of a short aliphatic chain and/or electron withdrawing groups (NO(2) and/or acetate) favor activity. These findings were confirmed using density functional theory (DFT), when calculating the LUMO density. In Principal Component Analysis (PCA), two significant principal components (PCs) explained more than 60% of the total variance. The best Partial Least Squares Regression (PLS) model showed an r2 of 0.86 and q2(cv) of 0.64 corroborating the SAR observations as well as demonstrating a greater probe N1 interaction for active compounds. Descriptors generated by TIP correlogram demonstrated the importance of the molecular shape for antifungal activity.

Preparation and Reactions of 2-azidoquinoline-3-carboxaldehyde with Primary Amines and Active Methylene Compounds

Preparation of 2-azidoquinoline-3-carboxaldehyde has been attempted and its tautomerism has been discussed. The reactivity of 2-azidoquinoline-3-carboxaldehyde towards primary amines, hydrazines and active methylene compounds has been investigated. Analytical and spectroscopic measurements have assisted the assignment of appropriate structures to the new reaction products.