Phytochemical investigation and anti-inflammatory potential of Atriplex leucoclada Boiss.

BACKGROUND: The plant kingdom has long been considered a valuable source for therapeutic agents, however, some plant species still untapped and need to be phytochemically and biologically explored. Although several Atriplex species have been investigated in depth, A. leucoclada, a halophytic plant native to Saudi Arabian desert, remains to be explored for its phytochemical content and biological potentials. Herein, the current study investigated the metabolic content and the anti-inflammatory potential of A. leucoclada. METHODS: Powdered aerial parts of the plant were defatted with n-hexane then the defatted powder was extracted with 80% methanol. n-Hexane extract (ATH) was analyzed using GC-MS, while the defatted extract (ATD) was subjected to different chromatographic methods to isolate the major phytoconstituents. The structures of the purified compounds were elucidated using different spectroscopic methods including advanced NMR techniques. Anti-inflammatory activity of both extracts against COX-1 and COX-2 enzymes were examined in vitro. Molecular docking of the identified compounds into the active sites of COX-1 and COX-2 enzymes was conducted using pdb entries 6Y3C and 5IKV, respectively. RESULTS: Phytochemical investigation of ATD extract led to purification and identification of nine compounds. Interestingly, all the compounds, except for 20-hydroxy ecdysone (1), are reported for the first time from A. leucoclada, also luteolin (6) and pallidol (8) are isolated for the first time from genus Atriplex. Inhibitory activity of ATD and ATH extracts against COX-1 and COX-2 enzymes revealed concentration dependent activity of both fractions with IC50 41.22, 14.40 µg/ml for ATD and 16.74 and 5.96 µg/ml for ATH against COX-1 and COX-2, respectively. Both extracts displayed selectivity indices of 2.86 and 2.80, respectively as compared to 2.56 for Ibuprofen indicating a promising selectivity towards COX-2. Molecular docking study supported in vitro testing results, where purified metabolites showed binding affinity scores ranged from -9 to -6.4 and -8.5 to -6.6 kcal/mol for COX-1 and 2, respectively, in addition the binding energies of GC-MS detected compounds ranged from -8.9 to -5.5 and -8.3 to -5.1 kcal/mol for COX-1 and 2, respectively as compared to Ibuprofen (-6.9 and -7.5 kcal/mol, respectively), indicating high binding affinities of most of the compounds. Analysis of the binding orientations revealed variable binding patterns depending on the nature of the compounds. Our study suggested A. leucoclada as a generous source for anti-inflammatory agents.

Characterization of Possible α-Glucosidase Inhibitors from Trigonella stellata Extract Using LC-MS and In Silico Molecular Docking.

The current study accentuates the significance of performing the multiplex approach of LC-HRESIMS, biological activity, and docking studies in drug discovery, taking into consideration a review of the literature. In this regard, the investigation of antioxidant and cytotoxic activities of Trigonella stellata collected from the Egyptian desert revealed a significant antioxidant capacity using DPPH with IC50 = 656.9 µg/mL and a moderate cytotoxicity against HepG2, MCF7, and CACO2, with IC50 values of 53.3, 48.3, and 55.8 µg/mL, respectively. The evaluation of total phenolic and flavonoid contents resulted in 32.8 mg GAE/g calculated as gallic acid equivalent and 5.6 mg RE/g calculated as rutin equivalent, respectively. Chemical profiling of T. stellata extract, using LC-HRESIMS analysis, revealed the presence of 15 metabolites, among which eleven compounds were detected for the first time in this species. Interestingly, in vitro testing of the antidiabetic activity of the alcoholic extract noted an α-glucosidase enzyme inhibitory activity (IC50 = 559.4 µg/mL) better than that of the standard Acarbose (IC50 = 799.9 µg/mL), in addition to a moderate inhibition of the α-amylase enzyme (IC50 = 0.77 µg/mL) compared to Acarbose (IC50 = 0.21 µg/mL). α-Glucosidase inhibition was also virtualized by binding interactions through the molecular docking study, presenting a high binding activity of six flavonoid glycosides, as well as the diterpenoid compound graecumoside A and the alkaloid fenugreekine. Taken together, the conglomeration of LC-HRESIMS, antidiabetic activity, and molecular docking studies shed light on T. stellata as a promising antidiabetic herb.

A multicomponent reaction to design antimalarial pyridyl-indole derivatives: Synthesis, biological activities and molecular docking.

Using fragment-based design strategy, new pyridyl-indole hybrids 4a-y and indole intermediates 3a-e were synthesized using multicomponent one pot reaction. The synthesized compounds were subjected to screening for antimalarial activity against chloroquine sensitive (D6) and chloroquine resistant (W2) strains of Plasmodium falciparum. Several compounds exhibited antimalarial activity with IC50 values in the range of 1.47-9.23 µM, and 1.16-7.66 µM, for D6 and W2 strains, respectively. Compounds 4a, 4k and 4u showed the highest selectivity index among all the tested compounds (S.I. ranged 3.8-10). Binding interactions between the active antimalarial compounds and the active site of quadruple mutant Plasmodium falciparum dihydrofolate reductase enzyme have been investigated using molecular docking analysis.

Phytochemical constituents and antioxidant activity of Echinops albicaulis.

Two thiophenes; 5-(3-buten-1-ynyl)-2,2'-bithiophene (2) and α-tertthienyl (9), two alkaloids; echinopsine (10) and echinorine (11), three flavonoids; genkwanin (5), apigenin (6), and rutin (7), two triterpenoids; lupeol acetate (1) and lupeol linoleate (4), together with 2,6,10-trimethyldodeca-2,6,10-triene (4) and ß-sitosterol glucoside (8) were isolated from the aerial parts of Echinops albicaulis. Antioxidant, antimicrobial and antiprotozoal activities were evaluated. E. albicaulis aqueous methanolic extract (50, 10, and 1 mg/mL) showed significant antioxidant activity comparable to the potent antioxidant, N-acetyl cysteine, moreover, the aqueous methanolic extract (1 mg/mL) significantly reduced intracellular reactive oxygen species in active cell cultures of human peripheral blood mononuclear cells under oxidative stress more than the reference antioxidant N-acetyl cysteine. None of the isolated compounds showed antimicrobial or antiprotozoal activities at concentration up to 20 µg/mL.

Monoamine oxidases inhibitors from Colvillea racemosa: Isolation, biological evaluation, and computational study.

Bioassay-guided fractionation and chemical investigation of Colvillea racemosa stems led to identification of two new α, ß-dihydroxydihydrochalcones, colveol A (1) and colveol B (2) along with fifteen known compounds. The structures were elucidated via interpretation of spectroscopic data. The absolute configurations of the dihydrochalcones 1 and 2 were assigned by a combination of chemical modification and electronic circular dichroism data. The isolated compounds were evaluated for their inhibition activity toward recombinant human monoamine oxidases (rhMAO-A and -B). Compound 1 demonstrated preferential inhibition against hMAO-A isoenzyme (IC50 0.62µM, SIA/B 0.02) while S-naringenin (13) and isoliquiritigein (15) demonstrated preferential hMAO-B inhibition (IC50 0.27 and 0.51µM, SIA/B 31.77 and 44.69, respectively). Fisetin (11) showed inhibition against hMAO-A with IC50 value of 4.62µM and no inhibitory activity toward hMAO-B up to 100µM. Molecular docking studies for the most active compounds were conducted to demonstrate the putative binding modes. It suggested that 1 interacts with Gln215, Ala111, Phe352, and Phe208 amino acid residues which have a role in the orientation and stabilization of the inhibitor binding to hMAO-A, while S-naringenin (13) occupies both entrance and substrate cavities and interacts with Tyr326, a critical residue in inhibitor recognition in hMAO-B.