Phenolic Constituents, Photoprotective Effect, and Antioxidant Capacities of Achillea ligustica All.

The present investigation was performed to figure out the chemical constituents and biological potential of polar extracts (AcOEt and BuOH) from Achillea ligustica, a medicinal species of the Asteraceae family. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) was utilized to conduct a preliminary analysis of the phytochemical profiles of the AcOEt and BuOH extracts. The analysis revealed the existence of twenty compounds in the AcOEt extract and twenty-two in the BuOH extract, classified into various types of secondary metabolites. Subsequently, the exudate from the plant yielded five flavonoids, including two 6-methoxyflavonols identified for the first time in this genus. The isolation of compounds from AcOEt and BuOH extracts was achieved through the combined use of column chromatography (silica gel and Sephadex LH-20) and preparative TLC chromatography. The structures have been elucidated using 1D and 2D NMR spectroscopy, alongside comparisons with research data. Our study measured the total phenolic and flavonoid contents and carried out a comprehensive range of antioxidant tests using DPPH, GOR, CUPRAC, reducing power, and O-phenanthroline assays. Both extracts exhibited considerable antioxidant potential and contained high levels of phenolic and flavonoid compounds. The photoprotective effect of the AcOEt and BuOH extracts was evaluated in vitro by measuring the sun protection factor. Both extracts exhibited a high capacity for UV radiation absorption. Consequently, this plant presents an intriguing prospect for future research focused on incorporating it into photoprotective cosmetic products and pharmaceutical formulations.

Phenanthrene and dihydrophenanthrene derivatives from Dioscorea communis with anticholinesterase, and antioxidant activities.

Five phenanthrene and two dihydrophenanthrene derivatives were isolated from the diethyl ether extract of fresh rhizomes of Dioscorea communis (L.), among them a phenanthrentriol 1 reported for the first time from Dioscoreaceae family and two dihydrophenanthrene derivatives 6 and 7 reported also for the first time from Dioscorea species. The structures of isolated compounds were elucidated using UV, IR, 1D-, 2D-NMR, and MS techniques. The anticholinesterase activity of extracts and four compounds was evaluated for the first time against acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes using Ellman method. Moreover, the antioxidant activity of extracts and three compounds has been investigated using DPPH radical scavenging, ABTS cation radical decolorization, CUPRAC, reducing power and ß-carotene bleaching assays.

The interaction of new plant flavonoids with rat liver mitochondria: relation between the anti- and pro-oxydant effect and flavonoids concentration.

Flavonoids are polyphenols derivatives of plant origin that possesses a broad range of pharmacological properties, including protection of cells and tissues against the deleterious effects of reactive oxygen species. Their antioxidant activity results from scavenging of free radicals and other oxidizing intermediates, from the chelation of iron or copper ions and from inhibition of oxidases. But a number of studies have found both anti and prooxidant effects for many of these compounds. These reasons prompted us to investigate whether flavonoids compounds alone or combined flavonoids had antioxidant, free radical scavenger and antiapoptotic properties. The investigation was carried in vitro using rat hepatic mitochondria. Respiratory control ratio (RCR), oxygen consumption, adenosine tri phosphate (ATP) synthesis, scavenging action, enzymatic activities of involved complexes, superoxide anion and the release of cytochrome C were measured to assess the mechanisms of action of these drugs. Our data showed that the decrease of RCR induced by high concentrations (0.1 mM and 0.01 mM) of all flavonoids tested was due to a common inhibition of oxidative phosphorylation (State 4) and activation of state 3. At the opposite mitochondrial swelling was slightly induced only by low concentrations (10(-8) and 10(-9) M) of the flavonoids. They had no effects on the mitochondrial complexes (I to V) activity. Furthermore the mitochondrial membrane potential was not affected by any flavonoids. The effect of flavonoids on superoxide anion generation was variable. All the flavonoids studied acted between 10(-4) M and 10(-6) M with no effects at lower concentrations. These effects were similar on lipid peroxidation (malondialdehyde [MDA] levels). We remarked a concentration-dependent in the effect of flavonoids since they acted as antioxidant and also as uncoupler at high concentrations, which is a risk for the cells. We conclude that flavonoids extracted from algerian plants have some protecting effects against oxidative stress by protecting the mitochondria.