hexacyanoferrate-iii and 1-1-diphenyl-2-picrylhydrazyl

Many natural antioxidants have poor pharmacokinetic properties that impair their therapeutic use. For hydroxycinnamic acids (HCAs) and other phenolic antioxidants, their major drawback is their low lipophilicity and a rapid metabolism. The difluoromethyl group may be considered as a 'lipophilic hydroxyl' due to its hydrogen bond donor and acceptor properties; this prompted us to assess it as a bioisosteric replacement of a phenolic hydroxyl for increasing the lipophilicity of HCAs.. Six difluoromethyl-substituted methyl cinnamates (4a-c, 5a-c) related to caffeic acid were synthesized and their antioxidant activity evaluated by chemical (FRAP, DPPH scavenging, inhibition of β-carotene bleaching, at 1-200 μm), electrochemical (differential pulse voltammetry, cyclic voltammetry) and cell-based (inhibition of lipid peroxidation in erythrocytes, at 1 and 50 μm) assays.. Analogues 4a-c and 5a-c were inactive in FRAP and DPPH assays and only those containing a free phenolic hydroxyl (4a and 5a) exhibited electrochemical activity although with high redox potentials. Compounds 4a,b and 5a,b were active in the inhibition of β-carotene bleaching assay and all analogues inhibited lipid peroxidation in the human erythrocytes assay.. Lipophilic difluoromethyl-substituted cinnamic esters retain radical scavenging capabilities that prove useful to confer antioxidant properties in a non-polar environment.

Topics: Antioxidants; beta Carotene; Biphenyl Compounds; Cells, Cultured; Coumaric Acids; Electrochemistry; Erythrocytes; Ferricyanides; Free Radicals; Humans; Hydrocarbons, Fluorinated; Lipid Peroxidation; Molecular Structure; Oxidation-Reduction; Picrates

'Ubtan' is a traditional herbal formulation in the Indian system of medicine being used in India and its subcontinent for a long time. Several commercial skin care formulations are marketed throughout this region as the name of Ubtan. Therefore, it is worthwhile to evaluate Ubtan in respect of its efficacy as skin care formulation.. The present study was designed for the preparation of Ubtan and standardization through the chromatographic techniques by using suitable phyto-markers. Further, its antioxidant, sun protection factor (SPF) and anti-tyrosinase potential have been explored.. Four in-house formulations (UF-1, UF-2, UF-3 and UF-4) were prepared by mixing a varied quantity of each powdered plants, i.e. turmeric (Curcuma longa L.), Chickpea (Cicer arietinum L.) and sandalwood (Santalum album L.). Optimization of the formulations was made by evaluating its biological activity through in vitro assay. Evaluation of physicochemical properties of the optimized formulation (UF-1) has been carried out by analysis of pH, flow properties and stability. Moreover, RP-HPLC (reverse phase - high performance liquid chromatography) and HPTLC (high performance thin layer chromatography) standardization of UF-1 was performed for its quantitative and qualitative analysis.. Ubtan formulations (UF-1to UF-4) showed free radical scavenging and ferric reducing potential. It may be due to its high phenolic and flavonoid content. Statistically, significant Pearson's correlation (r) was confirmed the positive correlation between phenolic content and SPF of the formulations. The tyrosinase inhibition study indicated that the formulations showed both diphenolase and monophenolase inhibitory activity. Among four formulations, UF-1 showed notable biological activity (p<0.05). The content of curcumin and ascorbic acid was found to be 1.6% and 2.1% w/w respectively in UF-1 through RP-HPLC estimation. Physiochemical properties of the UF-1 exhibited good flow rate and aqueous solubility. From the stability studies, it can be anticipated that the UF-1 was stable at 40°C for longer periods. Microbial load count and heavy metal content (lead-Pb, arsenic-As, mercury-Hg and cadmium-Cd) of the formulation was also within the permissible limit of a pharmacopeial standard.. This scientific exploration helps to set the quality and safety standard of traditional cosmetic formulation, Ubtan and its further use as an herbal skin care product.

Topics: Antioxidants; Ascorbic Acid; Bacterial Load; Biphenyl Compounds; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Chromatography, Thin Layer; Cicer; Consumer Product Safety; Curcuma; Curcumin; Dermatologic Agents; Dose-Response Relationship, Drug; Drug Compounding; Drug Contamination; Drug Stability; Enzyme Inhibitors; Ferricyanides; Hydrogen-Ion Concentration; India; Medicine, Traditional; Metals, Heavy; Monophenol Monooxygenase; Oxidation-Reduction; Phytotherapy; Picrates; Plant Preparations; Plants, Medicinal; Powders; Quality Control; Rheology; Risk Assessment; Santalum; Skin Care; Solubility; Spectrophotometry, Atomic; Spectrophotometry, Ultraviolet; Sunscreening Agents

Bitter cumin (Centratherum anthelminticum (L.) Kuntze), is a medicinally important plant. Earlier, we have reported phenolic compounds, antioxidant, and anti-hyperglycemic, antimicrobial activity of bitter cumin. In this study we have further characterized the antioxidative activity of bitter cumin extracts in various in vitro models.. Bitter cumin seeds were extracted with a combination of acetone, methanol and water. The antioxidant activity of bitter cumin extracts were characterized in various in vitro model systems such as DPPH radical, ABTS radical scavenging, reducing power, oxidation of liposomes and oxidative damage to DNA.. The phenolic extracts of bitter cumin at microgram concentration showed significant scavenging of DPPH and ABTS radicals, reduced phosphomolybdenum (Mo(VI) to Mo(V)), ferricyanide Fe(III) to Fe(II), inhibited liposomes oxidation and hydroxyl radical induced damage to prokaryotic genomic DNA. The results showed a direct correlation between phenolic acid content and antioxidant activity.. Bitter cumin is a good source of natural antioxidants.

Topics: Anti-Bacterial Agents; Antioxidants; Asteraceae; Benzothiazoles; Biphenyl Compounds; DNA Damage; Ferricyanides; Hydroxyl Radical; Liposomes; Molybdenum; Oxidation-Reduction; Phenols; Picrates; Plant Extracts; Plants, Medicinal; Seeds; Sulfonic Acids; Thiazoles

Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. In addition, these new compounds and five recently reported 3-alkyl-4-(pmethoxybenzoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were screened for their antioxidant activities.

Topics: Antioxidants; Biphenyl Compounds; Ferricyanides; Free Radical Scavengers; Hydrazines; Molecular Structure; Oxidation-Reduction; Picrates; Potentiometry; Spectrum Analysis; Triazoles