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This study investigated the effect of drought stress on the amount of phenolic and flavonoid compounds as well as H 2 O 2 and malondialdehyde (MDA) in Achillea pachycephala. The expression patterns of the key genes and their molecular mechanisms in the phenylpropanoid pathway (PAL, CHS, CHI, F3H, F3'H, F3'5'H, FLS) were also assessed during drought stress using quantitative real-time polymerase chain reaction (qRT-PCR). The samples were harvested at 0, 7, 14, 21 and 28 days after exposure to drought stress. High-performance liquid chromatography (HPLC) analysis was performed to determine the changes of phenolic and flavonoid compounds - chlorogenic acid, caffeic acid, rutin, luteolin-7-O-glycoside, 1,3-dicaffeoylquinic acid, apigenin-7-O-glycoside, luteolin, apigenin and kaempferol - during stress conditions. Concentrations of most of the compounds increased with increasing drought stress duration. Most of the phenolic acids continued to accumulate with increasing duration of stress, while flavonoids dramatically decreased at day 28 of stress. Chlorogenic acid was the most abundant phenolic acid (4.97 mg/100 g dry weight [DW]) at the beginning of the experiment, while it decreased at day 7 and increased again at day 21. However, different trends were observed for some flavonoids, such as luteolin and apigenin. At the beginning of stress treatment, high accumulation of free radicals (H 2 O 2 ) and lipid peroxidation (MDA) led to elevated expression of most of the flavonoid genes. MDA increased from 22.66 to 43.28 μmol g -1 DW at day 28. CHS gene expression was elevated at day 7, while chi gene expression remained unchanged. At the end of the stress period, most of the flavonoid concentrations and expression of the relevant genes also increased. The results can facilitate selection of appropriate drought conditions to obtain the highest levels of flavonoids such as luteolin and apigenin and phenolic compounds such as chlorogenic acid for improved health benefits., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Cholinesterase inhibition is one of the most treatment strategies against Alzheimer's disease (AD) where metal accumulation is also strongly associated with pathology of the disease. In the current study, we assessed inhibitory effect against acetyl- (AChE) and butyrylcholinesterase (BChE) and metal-chelating capacity of twelve diterpenes: arucadiol, miltirone, tanshinone IIa, 1-oxomiltirone, cryptotanshinone, 1,2-didehydromiltirone, 1,2-didehydrotanshinone IIa, 1β-hydroxycryptotanshinone, 15,16-dihydrotanshinone, tanshinone I, isotanshinone II, 1(S)-hydroxytanshinone IIa, and rosmarinic acid, isolated from Perovskia atriplicifolia and Salvia glutinosa. The compounds were tested at 10 μg/mL using ELISA microtiter assays against AChE and BChE. QSAR and molecular docking studies have been also performed on the active compounds. All of the compounds showed higher [e.g., IC 50  = 1.12 ± 0.07 μg/mL for 1,2-didehydromiltirone, IC 50  = 1.15 ± 0.07 μg/mL for cryptotanshinone, IC 50  = 1.20 ± 0.03 μg/mL for arucadiol, etc.)] or closer [1,2-didehydrotanshinone IIa (IC 50  = 5.98 ± 0.49 μg/mL) and 1(S)-hydroxytanshinone IIa (IC 50  = 5.71 ± 0.27 μg/mL)] inhibition against BChE as compared to that of galanthamine (IC 50  = 12.56 ± 0.37 μg/mL), whereas only 15,16-dihydrotanshinone moderately inhibited AChE (65.17 ± 1.39%). 1,2-Didehydrotanshinone IIa (48.94 ± 0.26%) and 1(S)-hydroxytanshinone IIa (47.18 ± 5.10%) possessed the highest metal-chelation capacity. The present study affords an evidence for the fact that selective BChE inhibitors should be further investigated as promising candidate molecules for AD therapy., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

We evaluated the antioxidant properties of four main flavones from Scutellaria baicalensis: baicalein, wogonin and their glucuronides - baicalin and wogonoside. We used three in vitro assays: free radical scavenging with 2,2'-diphenylpicrylhydrazyl radical, transition metal ions reducing power by phosphomolybdenum assay and inhibition of the hydroxyl radical-induced peroxidation of linoleic acid assay. All flavones have antioxidant capacity, which differs depending on the structure and mechanisms of activity. In all tests, only baicalein - the aglycone with three adjacent hydroxyl groups - exhibited consistent antioxidant effect. Wogonin protected linoleic acid against oxidation. Baicalin displayed less potent antioxidant properties whereas wogonoside did not have significant antioxidant activity.

A computational study was carried out to identify the structural determinant controlling the affinity, specificity and binding strength of several saturated and unsaturated fatty acids with Oryza sativa (Indica group) nonspecific lipid transfer protein (nsLTP2). Association between the number, position and conformation of hydrophobic patches and lipid binding properties of the protein was evidenced by docking analysis. Binding affinity is influenced by the number of carbon atoms, location of double bonds and hydroxyl group in the acyl chain. The results may direct at developing applications in LTP-mediated transport and controlled release of low molecular weight drugs., (© 2013 Elsevier Ltd. All rights reserved.)

The antioxidant and antimutagenic properties of the extract from the oriental natural drug - Belamcanda chinensis (L.)DC. (Iridaceae) rhizomes have been examined. Three different antioxidant assays and Salmonella antimutagenic test have been used. The extract has strong free radical scavenging activity as shown by the DPPH assay with EC50 of 63.4 microg/mL. Similarly, the high ability to reduce the transition metal ions was shown by phosphomolybdenum assay as well as effective prevention of hydroxyl radical induced linoleic acid peroxidation. The latter averaged 77.9% with an EC50 of 45 microg/mL. The mutations induced in two Salmonella typhimurium strains (TA98 and TA100) by both directly (NQNO) and indirectly acting (2AF) chemical mutagens were inhibited efficiently in dose dependent manner for concentrations of 50-500 microg/mL. The inhibition percentage in TA98 was 62.8% for direct mutagen and 94.4% for enzymatically activated promutagen. In TA100 the inhibition was 82.7% and 73.5%, respectively.

The four flavonoids baicalin, baicalein, wogonoside, and wogonin have been isolated from Scutellaria baicalensis (Lamiaceae) root extract as main bioactive components. We evaluated their antimutagenic activity as potential chemopreventive natural substances using the Ames test. Free radical scavenging properties have also been measured with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Both crude extract and isolated flavone glycosides and aglycones have antimutagenic and free radical scavenging properties. The lipophilic flavone baicalein has been confirmed to be the most powerful antimutagen among the compounds tested.