Kinetic and adsorption isotherm studies of Malachite Green dye onto surfactant-tailored alginate hydrogel beads: An influence of surfactant hydrophobicity.

This study details the synthesis and characterization of surfactant-modified sodium alginate hydrogel beads crosslinked with Ba2+ ions through ionotropic gelation. Cationic surfactants such as, dodecyltrimethylammonium bromide (DTAB), didodecyldimethylammonium bromide (DDAB), and butanediyl-α,ω-bis-(dimethyldodecylammonium bromide) (GEM), were employed in the modification process. The surfactant-modified ALG-DTAB, ALG-DDAB, and ALG-GEM beads were investigated for the removal of cationic dye Malachite Green (MG) to elucidate the impact of hydrophobicity of amphiphiles on the adsorption process. The characterizations were carried out using Rheometry, Field Emission Scanning Electron Microscopy (FESEM), Infrared Spectroscopy (IR), and Energy Dispersive X-ray Spectroscopy (EDX). Under optimized conditions, ALG-GEM and ALG-DDAB demonstrated highest maximum adsorption capacity (Qmax > 700 mgg-1). The adsorption data fitted well to pseudo-second order kinetic and Langmuir adsorption models, suggesting the involvement of chemisorption phenomena with notable contributions from pore diffusion. The effects of pH, initial dye concentration, adsorbent dose, temperature, and competing ions on the removal of MG were investigated. Interestingly, ALG-GEM beads exhibited an increase in adsorption capacity with rising pH and a subsequent decrease with increasing temperature, showcasing optimal adsorption at pH 7.0 and 25 °C. The study proposes that ALG beads modified with cationic surfactants with higher hydrophobicity could offer a promising avenue in wastewater treatment processes.

Synthesis, antioxidant, antiproliferative activity, molecular docking and DFT studies of novel isoxazole derivatives of diosgenin, a steroidal sapogenin from Dioscorea deltoidea.

Diosgenin [25R-spirost-5-en-3ß-ol], isolated from Dioscorea deltoidea was used as a starting material for synthesizing its various isoxazole derivatives. A library of fifteen isoxazole analogues (DG1-DG15) were synthesised via modification at the C-3 hydroxyl group. The resulting analogues were fully characterized by spectral techniques and evaluated for their antioxidant and anticancer activity against four breast cancer cell lines; MDA-MB-231, MDA-MB-468, MCF-7, and 4 T1, using MTT assay. Molecular docking studies were carried out for all analogues with EGFR protein (PDB id: 6LUD) to check their activity by inhibiting EGFR protein, which is an effective strategy for cancer cell death. Furthermore, DFT studies were carried out for four analogues. Among all analogues, compound DG6 and DG9 showed the highest scavenging activity and compound DG9 exhibited a maximum cytotoxic effect on the MDA-MB-468 and MCF-7 cell lines with an IC50 value of 6.25 µg/mL and 6.81 µg/mL, while compound DG5 was the least potent (IC50 25.89 µg/mL). Molecular docking results revealed that DG8 and DG9 afforded the highest binding energy of -14.33 and - 14.71 kcal/mol, respectively for the target EGFR protein. These results demonstrate the potential of diosgenin analogues as drug candidates for breast cancer therapy. Furthermore, DFT studies revealed that the molecules are more polarizable and have smaller energy gap between their HOMO and LUMO orbitals, the smallest being of DG9 (3.221 eV) and hence are more reactive.

Synthesis and Fabrication of Collagen-Coated Ostholamide Electrospun Nanofiber Scaffold for Wound Healing.

A novel scaffold for effective wound healing treatment was developed utilizing natural product bearing collagen-based biocompatible electrospun nanofibers. Initially, ostholamide (OSA) was synthesized from osthole (a natural coumarin), characterized by 1H, 13C, DEPT-135 NMR, ESI-MS, and FT-IR spectroscopy analysis. OSA was incorporated into polyhydroxybutyrate (PHB) and gelatin (GEL), which serve as templates for electrospun nanofibers. The coating of OSA-PHB-GEL nanofibers with collagen resulted in PHB-GEL-OSA-COL nanofibrous scaffold which mimics extracellular matrix and serves as an effective biomaterial for tissue engineering applications, especially for wound healing. PHB-GEL-OSA-COL, along with PHB-GEL-OSA and collagen film (COLF), was characterized in vitro and in vivo to determine its efficacy. The developed PHB-GEL-OSA-COL nanofibers posed an impressive mechanical stability, an essential requirement for wound healing. The presence of OSA had contributed to antimicrobial efficacy. These scaffolds exhibited efficient antibacterial activity against common wound pathogens, Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The zones of inhibition were observed to be 14 ± 22 and 10 ± 2 mm, respectively. It was observed that nanofibrous scaffold had the ability to release OSA in a controlled manner, and hence, OSA would be present at the site of application and exhibit bioactivity in a sustained manner. PHB-GEL-OSA-COL nanofiber was determined to be stable against enzymatic degradation, which is the most important parameter for promoting proliferation of cells contributing to repair and remodeling of tissues during wound healing applications. As hypothesized, PHB-GEL-OSA-COL was observed to imbibe excellent cytocompatibility, which was determined using NIH 3T3 fibroblast cell proliferation studies. PHB-GEL-OSA-COL exhibited excellent wound healing efficacy which was confirmed using full thickness excision wound model in Wistar rats. The rats treated with PHB-GEL-OSA-COL nanofibrous scaffold displayed enhanced healing when compared to untreated control. Both in vitro and in vivo analysis of PHB-GEL-OSA-COL presents a strong case of therapeutic biomaterial suiting wound repair and regeneration.

Genicunolide A, B and C: three new triterpenoids from Euphorbia geniculata.

Three new triterpenoids, designated as genicunolide A (1), B (2) and C (3), along with friedelin (4) and friedelinol (5), were isolated from the aerial parts of Euphorbia geniculata. They were characterized as 1ß-acetoxy-3ß-hydroxy-11α,12α-oxidotaraxer-14-ene, 1ß,3ß-diacetoxy-21α-hydroxy-11α,12α-oxidotaraxer-14-ene and 3ß,9α,20α-trihydroxy-Ψ-taraxast-5-ene, respectively, by spectral and chemical methods.

Isolation, cytotoxicity evaluation and HPLC-quantification of the chemical constituents from Prangos pabularia.

Phytochemical analysis of the dichloromethane:methanol (1:1) extract of root parts of Prangos pabularia led to the isolation of twelve cytotoxic constituents, viz., 6-hydroxycoumarin (1), 7-hydroxycoumarin (2), heraclenol-glycoside (3), xanthotoxol (4), heraclenol (5), oxypeucedanin hydrate (6), 8-((3,3-dimethyloxiran-2-yl)methyl)-7-methoxy-2H-chromen-2-one (7), oxypeucedanin hydrate monoacetate (8), xanthotoxin (9), 4-((2-hydroxy-3-methylbut-3-en-1-yl)oxy)-7H-furo[3,2-g]chromen-7-one (10), imperatorin (11) and osthol (12). The isolates were identified using spectral techniques in the light of literature. 3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity screening of the isolated constituents was carried out against six human cancer cell lines including lung (A549 and NCI-H322), epidermoid carcinoma (A431), melanoma (A375), prostate (PC-3) and Colon (HCT-116) cell lines. Osthol (12) exhibited the highest cytotoxicity with IC50 values of 3.2, 6.2, 10.9, 14.5, 24.8, and 30.2 µM against epidermoid carcinoma (A431), melanoma (A375), lung (NCI-H322), lung (A549), prostate (PC-3) and colon (HCT-116) cell lines respectively. Epidermoid carcinoma cell line A431 was sensitive to most of the compounds followed by lung (A549) cancer cell line. Finally a simple and reliable HPLC method was developed (RP-HPLC-DAD) and validated for the simultaneous quantification of these cytotoxic constituents in Prangos pabularia. The extract was analyzed using a reversed-phase Agilent ZORBAX eclipse plus column C18 (4.6×250 mm, 5 µm) at 250 nm wavelength using a gradient water-methanol solvent system at a flow rate of 0.8 ml/min. The RP-HPLC method is validated in terms of recovery, linearity, accuracy and precision (intra and inter-day validation). This method, because of shorter analysis time, makes it valuable for the commercial quality control of Prangos pabularia extracts and its future pharmaceutical preparations.