Synthesis of Flavonols and Assessment of Their Biological Activity as Anticancer Agents.

A series of flavanols were synthesized to assess their biological activity against human non-small cell lung cancer cells (A549). Among the sixteen synthesized compounds, it was observed that compounds 6k (3.14 ± 0.29 µM) and 6l (0.46 ± 0.02 µM) exhibited higher potency compared to 5-fluorouracil (5-Fu, 4.98 ± 0.41 µM), a clinical anticancer drug which was used as a positive control. Moreover, compound 6l (4'-bromoflavonol) markedly induced apoptosis of A549 cells through the mitochondrial- and caspase-3-dependent pathways. Consequently, compound 6l might be developed as a candidate for treating or preventing lung cancer.

Chemical Characterization and Anti-HIV-1 Activity Assessment of Iridoids and Flavonols from Scrophularia trifoliata.

Plants are the everlasting source of a wide spectrum of specialized metabolites, characterized by wide variability in term of chemical structures and different biological properties such antiviral activity. In the search for novel antiviral agents against Human Immunodeficiency Virus type 1 (HIV-1) from plants, the phytochemical investigation of Scrophularia trifoliata L. led us to isolate and characterize four flavonols glycosides along with nine iridoid glycosides, two of them, 5 and 13, described for the first time. In the present study, we investigated, for the first time, the contents of a methanol extract of S. trifoliata leaves, in order to explore the potential antiviral activity against HIV-1. The antiviral activity was evaluated in biochemical assays for the inhibition of HIV-1Reverse Transcriptase (RT)-associated Ribonuclease H (RNase H) activity and HIV-1 Integrase (IN). Three isolated flavonoids, rutin, kaempferol-7-O-rhamnosyl-3-O-glucopyranoside, and kaempferol-3-O-glucopyranoside, 8-10, inhibited specifically the HIV-1 IN activity at submicromolar concentration, with the latter being the most potent, showing an IC50 value of 24 nM.

Literature Evidence and ARRIVE Assessment on Neuroprotective Effects of Flavonols in Neurodegenerative Diseases' Models.

BACKGROUND AND OBJECTIVE: This paper was based on a literature search of PubMed and Scielo databases using the keywords "Flavonoids, Neuroprotection, Quercetin, Rutin, Isoquercitrin, Alzheimer, Parkinson, Huntington" and combinations of all the words. METHOD: We collected relevant publications, during the period of 2000 to 2016, emphasizing in vivo and in vitro studies with neurological assessment of flavonol's potentials, as well as classifying studies according to evidence levels, in order to elucidate evidence-based literature and its application on clinical research. In addition, we highlight the importance of flavonols in modern research fields, indicating their neuroprotective potential and use thereof as preventive and therapeutic treatment of numerous neurodegenerative disease. Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, represent worldwide a major health problem with great financial impact. They are multifactorial diseases, hallmarked by similar pathogenesis that covers conditions such as oxidative stress, formation of free radicals, abnormal protein dynamics (degradation and aggregation), mitochondrial dysfunction, lipid peroxidation and cellular death or senescence. Flavonols are polyphenolic compounds, widely distributed in the plant kingdom and found in high concentrations in vegetables, fruits and teas. Their neuroprotective effects are mainly related to their antioxidant, anti-proliferative and anti-inflammatory properties. CONCLUSION: It was this paper's intention to contribute with an evidence analysis of recent studies approaching neuroprotective effects of flavonols and the potential to conduct human clinical studies.

Assessment of isorhamnetin 3-O-neohesperidoside from Acacia salicina: protective effects toward oxidation damage and genotoxicity induced by aflatoxin B1 and nifuroxazide.

Antioxidant activity of isorhamnetin 3-O-neohesperidoside, isolated from the leaves of Acacia salicina, was determined by the ability of this compound to inhibit xanthine oxidase activity and to scavenge the free radical 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(.-)) diammonium salt. Antigenotoxic activity was assessed using the SOS chromotest assay. This compound has the ability to scavenge the ABTS(.+) radical by a hydrogen donating mechanism. We also envisaged the study of the antioxidant effect of this compound by the enzymatic xanthine/xanthine oxidase (X/XOD) assay. Results indicated that isorhamnetin 3-O-neohesperidoside was a potent inhibitor of xanthine oxidase and superoxide anion scavengers. Moreover, this compound induced an inhibitory activity against nifuroxazide and aflatoxine B1 (AFB1) induced genotoxicity. Taken together, these observations provide evidence that isorhamnetin 3-O-neohesperidoside isolated from the leaves of A. salicina is able to protect cells against the consequences of oxidative stress.