Antioxidant and Pro‐Oxidant Evaluation of a Potentilla alba L. Rhizome Extract

Using spectrophotometric methods, a H₂O‐soluble Potentilla alba L. rhizome extract was evaluated phytochemically, i.e., the total phenol, flavonoid, flavonol, flavanone, and proanthocyanidin contents were determined, and its antioxidant and pro‐oxidant properties, i.e., the Fe^III reductive and the Fe^II chelating properties, the 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH^.), N,N‐dimethyl‐p‐phenylenediamine (DMPD^.+), and superoxide anion radical (O$\rm{{_{2}^{{^\cdot} -}}}$ )‐scavenging activities, the capacity to inhibit hydroxyl radical (HO^.)‐mediated deoxy‐D ‐ribose and phospholipid degradation, and the interaction with the Cu‐catalyzed HO^.‐mediated DNA degradation, were determined. The extract was found to contain a range of phenolic compounds recognized to possess strong antioxidant‐like properties. Moreover, the extract demonstrated dose‐dependent activities in all the antioxidant assays with the exception of the DNA‐degradation assay, where the components within the extract interfered with the assay components at concentrations ≥1.00 mg/ml. Potentilla species are known for their curative properties, with aerial/subterranean parts being prescribed for numerous indications. The data presented here suggests, though does not conclude, that the rhizomes contain compounds possessing a range of antioxidant‐related properties, which may underpin the therapeutic, viz., anti‐inflammatory and adaptogenic effects, ascribed to species of this genus.     

The biological activities of fish peptides and methods of their isolation

Fish, like other aquatic organisms, are a potential source of structurally diverse bioactive compounds. Studies of the pharmacological effects of fish peptides have revealed their antihypertensive, immunomodulatory, antioxidant, antitumor, and antimicrobial activities. Analysis of the literature data confirms that fish can be used not only for nutritional purposes, but also as a source of unique peptides with a broad spectrum of biological activities. Further investigations will allow the inclusion of fish peptides as acting agents in modern medicinal drugs.     

Phenolic constituents of Gnaphalium uliginosum L.

The herb Gnaphalium uliginosum L. is an annual plant widely used in Russian and Bulgarian phytotherapy in the treatment of hypertension, thrombophlebitis, phlebothrombosis and ulcers. Decoction and infusion of G. uliginosum are known to possess anti-inflammatory, astringent, and antiseptic properties. Oil extracts are used in the treatment of laryngitis, upper respiratory catarrh and tonsillitis. However, there is still lack of information about the active compounds.Ten phenolic compounds have been identified from the aerial parts of G. uliginosum including seven flavonoid glucosides and three phenylpropanoids. Their chemical structures were elucidated on the basis of 1D and 2D NMR and HRESIMS. Among the identified compounds the first full assignments of the ¹H and ¹³C NMR spectra of, 5,7,4′-trihydroxy-6,3′-dimethoxyflavone-7-O-β-d-(6″-O-caffeoyl)-glucopyranoside are firstly reported in this paper.     

Separation and free radical-scavenging activity of major curcuminoids of Curcuma longa using HPTLC-DPPH method

A direct HPTLC assay was developed for the determination of total curcuminoids and three individual curcuminoids, curcumin, demethoxycurcumin and bisdemethoxycurcumin. In addition, a new procedure was developed to separate and quantitative the free radical-scavenging activity of individual compounds from the rhizome of Curcuma longa L. (Zingiberaceae) based on the combination of HPTLC with a diode array detector (DAD) and post chromatographic DPPH(*) radical derivatisation. It was established that both individual curcuminoids and the extract of C. longa were capable of scavenging DPPH(*) radicals. From the estimated ID(50) values, it can be seen that the order of activity was curcumin > demethoxycurcumin > bisdemethoxycurcumin > ascorbic acid. However, the ID(50) values of curcuminoids were not significantly different. The data indicates the presence of a synergistic mechanism of antiradical activity of curcuminoids.     

Determination and pharmacokinetic study of taxifolin in rabbit plasma by high-performance liquid chromatography

Taxifolin has been widely used in the treatment of cerebral infarction and sequelae, cerebral thrombus, coronary heart disease and angina pectoris. A reliable sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method with UV detection for the pharmacokinetic study of taxifolin in rabbit plasma after enzymatic hydrolysis was developed and validated for the first time. Taxifolin, with biochanin A as the internal standard, was extracted from plasma samples by liquid/liquid extraction after hydrolysis with β-glucuronidase and sulfatase. Chromatographic separation was conducted on a Luna C18 column (4.6 mm×150 mm, 5 μm particle size) and pre-column (2.0 mm, the same sorbent). Two-step linear gradient elution with acetonitrile and 0.03% water solution of trifluoroacetic acid as mobile phase at a flow rate of 1.0 ml/min was used. The UV detector is set at 290 nm. The elution time for taxifolin and biochanin A was approximately 7.9 and 18.3 min, respectively. The calibration curve of taxifolin was linear (r>0.9997) over the range of 0.03–5.0 μg/ml in rabbit plasma. The limit of detection (LOD) and limit of quantification (LOQ) for taxifolin were 0.03 and 0.11 μg/ml, respectively. The present method was successfully applied for the estimation of the pharmacokinetic parameters of taxifolin following intravenous and oral administration of lipid solution to rabbits. The absolute bioavailability of taxifolin after oral administration of lipid solution was 36%.     

Evaluation of fractions extracted from Polycladia myrica: biological activities,UVR protective effect,and stability of cream formulation based on it

Journal of Applied Phycology - Phlorotannins are polyphenolic compounds in brown algae and can be used as a natural UV filter in sunscreen formulations. The aim of the present study was to...