Spectral characteristics of the flavones and anthocyanins present in passionflower (Passiflora incarnata).

Rich in antioxidants with a variety of flavones and anthocyanins, passionflower/fruit has been extensively used in food, beverage, medicinal, and natural dyes industries. The individual components present in passionflower are identified by extracting them in methanol, partitioning them between ethyl acetate and aqueous layers, and recording their ESI mass spectrometric data. The steady-state absorption and fluorescence spectra of the extract in methanol and dimethyl sulfoxide are recorded and the lifetime of the fluorescing species is reported. The pH dependence of the absorption spectrum confirms the presence of the anthocyanins.

Dual-binding conjugates of diaromatic guanidines and porphyrins for recognition of G-quadruplexes.

The first conceptualised class of dual-binding guanine quadruplex binders has been designed, synthesised and biophysically studied. These compounds combine diaromatic guanidinium systems and neutral tetra-phenylporphyrins (classical binding moiety for guanine quadruplexes) by means of a semi-rigid linker. An extensive screening of a variety of guanine quadruplex structures and double stranded DNA via UV-vis, FRET and CD experiments revealed the preference of the conjugates towards guanine quadruplexes. Additionally, docking studies indicate the potential dual mode of binding.

Cyclopenta[b]annulation of Heteroarenes by Organocatalytic γ'[C(sp3 )-H] Functionalization of Ynones.

A new approach for the cyclopenta[b]annulation of heteroarenes through metal-free and directing-group-free γ'[C(sp3 )-H] functionalization and intramolecular hydroalkylation of ynones has been developed. In an unprecedented event, nucleophilic addition of an organophosphine to the designed ynones triggers γ'[C(sp3 )-H] functionalization, leading to the formation of heteroaryl-based ortho-quinodimethane (oQDM) intermediates that undergo carbocyclization to provide cyclopentannulated heteroarenes in good yields and excellent stereoselectivities. Deuterium-labeling experiments substantiated the proposed reaction mechanism as well as the speculated epimerization.

Synthesis, biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors.

As a part of our continued efforts to discover new COX inhibitors, a series of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones were synthesized and evaluated for in vitro COX inhibitory potential. Within this series, seven compounds (3a-d, 3h, 3k and 3q) were identified as potential and selective COX-2 inhibitors (COX-2 IC50's in 1.79-4.35µM range; COX-2 selectivity index (SI)=6.8-16.7 range). Compound 3b emerged as most potent (COX-2 IC50=1.79µM; COX-1 IC50 >30µM) and selective COX-2 inhibitor (SI >16.7). Further, compound 3b displayed superior anti-inflammatory activity (59.86% inhibition of edema at 5h) in comparison to celecoxib (51.44% inhibition of edema at 5h) in carrageenan-induced rat paw edema assay. Structure-activity relationship studies suggested that N-phenyl ring substituted with p-CF3 substituent (3b, 3k and 3q) leads to more selective inhibition of COX-2. To corroborate obtained experimental biological data, molecular docking study was carried out which revealed that compound 3b showed stronger binding interaction with COX-2 as compared to COX-1.

Synthesis, biological evaluation, molecular docking and theoretical evaluation of ADMET properties of nepodin and chrysophanol derivatives as potential cyclooxygenase (COX-1, COX-2) inhibitors.

Nepodin and chrysophanol, isolated from Rumex nepalensis roots, showed significant cyclooxygenase (COX) inhibitory activity. To further optimize these lead molecules and study structure activity relationship (SAR), eighteen derivatives of nepodin and nine derivatives of chrysophanol were synthesized and evaluated for COX-1 and COX-2 inhibitory potential. Among the synthesized compounds, four nepodin (1f, 1g, 1h and 1i) and three chrysophanol (2e, 2f and 2h) derivatives displayed more pronounced COX-2 inhibition than their respective lead molecule. Further, compounds 1f, 1g, 2e and 2h exhibited better anti-inflammatory activity than ibuprofen in carrageenan-induced rat paw edema assay. Taking into account the in vitro and in vivo results, molecular docking and in silico prediction of ADMET properties of compounds were carried out respectively.

Analysis of flavonoids and iridoids in Vitex negundo by HPLC-PDA and method validation.

The leaves of Vitex negundo have been reported to contain various bioactive constituents including iridoids and flavonoids. This is the first report on the simultaneous determination of iridoids and flavonoids by HPLC in three different samples of V. negundo leaves collected from three regions of India. Separation of iridoids and flavonoids was accomplished by HPLC and further elaborated for their quantification in V. negundo leaves using a C-18 column with detection at 254 and 330 nm, respectively. The developed HPLC method showed good linearity (r2 > or = 0.999), high precision (RSD < 5%) and a good recovery (99.3-103.0%) of the compounds. All the validation parameters of the developed HPLC were found to be within the permissible limits according to the ICH guidelines. The developed method was robust, accurate and reliable for the quality control of V. negundo leaves.

Rotenoids from Boerhaavia diffusa as potential anti-inflammatory agents.

Five new (2, 3, 5, 7, and 9) and four known rotenoids (1, 4, 6, and 8) were isolated from a methanol extract of Boerhaavia diffusa roots. The structures of the new rotenoids were elucidated by spectroscopic data interpretation. The 70% ethanol extract, a rotenoid-rich fraction, and all isolated rotenoids were evaluated for their COX-1 and COX-2 inhibitory activities. Among the rotenoids tested, compound 7 showed the most potent COX-1 and COX-2 inhibition, with IC50 values of 21.7 ± 0.5 and 25.5 ± 0.6 µM, respectively. Boeravinone B (6) exhibited significant anti-inflammatory activity (56.6% at 50 mg/kg) when evaluated in an in vivo carrageenan-induced rat paw model.