Comparative Evaluation of the Antioxidant and Anti-Alzheimer's Disease Potential of Coumestrol and Puerarol Isolated from Pueraria lobata Using Molecular Modeling Studies.

The current study assesses the antioxidant effects of two similar isoflavonoids isolated from Pueraria lobata, coumestrol and puerarol, along with the cholinergic and amyloid-cascade pathways to mitigate Alzheimer's disease (AD). Antioxidant activity was evaluated via 1,1-diphenyl-2-picryhydrazyl (DPPH) and peroxynitrite (ONOO-) scavenging ability further screened via ONOO--mediated nitrotyrosine. Similarly, acetyl- and butyrylcholinesterase (AChE/BChE) and ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities were assessed together with docking and kinetic studies. Considering DPPH and ONOO- scavenging activity, coumestrol (EC50 values of 53.98 and 1.17 µM) was found to be more potent than puerarol (EC50 values of 82.55 and 6.99 µM) followed by dose dependent inhibition of ONOO--mediated nitrotyrosine. Coumestrol showed pronounced AChE and BChE activity with IC50 values of 42.33 and 24.64 µM, respectively, acting as a dual cholinesterase (ChE) inhibitor. Despite having weak ChE inhibitory activity, puerarol showed potent BACE1 inhibition (28.17 µM). Kinetic studies of coumestrol showed AChE and BChE inhibition in a competitive and mixed fashion, whereas puerarol showed mixed inhibition for BACE1. In addition, docking simulations demonstrated high affinity and tight binding capacity towards the active site of the enzymes. In summary, we undertook a comparative study of two similar isoflavonoids differing only by a single aliphatic side chain and demonstrated that antioxidant agents coumestrol and puerarol are promising, potentially complementary therapeutics for AD.

The Stimulatory Effect of Strontium Ions on Phytoestrogens Content in Glycine max (L.) Merr.

The amount of secondary metabolites in plants can be enhanced or reduced by various external factors. In this study, the effect of strontium ions on the production of phytoestrogens in soybeans was investigated. The plants were treated with Hoagland's solution, modified with Sr(2+) with concentrations ranging from 0.5 to 3.0 mM, and were grown for 14 days in hydroponic cultivation. After harvest, soybean plants were separated into roots and shoots, dried, and pulverized. The plant material was extracted with methanol and hydrolyzed. Phytoestrogens were quantified by HPLC. The significant increase in the concentration of the compounds of interest was observed for all tested concentrations of strontium ions when compared to control. Sr(2+) at a concentration of 2 mM was the strongest elicitor, and the amount of phytoestrogens in plant increased ca. 2.70, 1.92, 3.77 and 2.88-fold, for daidzein, coumestrol, genistein and formononetin, respectively. Moreover, no cytotoxic effects were observed in HepG2 liver cell models after treatment with extracts from 2 mM Sr(2+)-stressed soybean plants when compared to extracts from non-stressed plants. Our results indicate that the addition of strontium ions to the culture media may be used to functionalize soybean plants with enhanced phytoestrogen content.

[Chemical constituents from Spatholobus sinensis].

Spatholobus sinensis is a plant of the Spatholobus genus (Leguminosae family). Its caulis are used as "ji-xue-teng" regionally. However, to our knowledge, no phytochemical investigation on S. sinensis has been reported to date. In this study, eight compounds were isolated from the ethanol extract of the caulis of S. sinensis, by solvents extraction and column chromatography methods. By analysis of their physic-chemical constants and spectral data, the structures of 8 compounds were identified as spatholosineside A (1), 2',4',5,7-tetrahydroxyisoflavone (2), isoliquiritigenin (3), lupinalbin A (4), coumestrol (5), naringenin (6), protocatechuic acid (7), leonuriside A (8). Compound 1 is a new compound.

Antimicrobial isoflavonoids from Erythrina crista galli infected with Phomopsis sp.

The isoflavonoids coumestrol, genistein and daidzein have been isolated and identified by bioassay-guided fractionation from the acetone extract of Erythrina crista galli young twigs infected with Phomopsis sp. These compounds showed antimicrobial activity against Bacillus brevis (MIC values 16.3, 64.8 and 137.8 microM, respectively). This is the first time that coumestrol, besides lutein and n-nonacosane, are reported in this species.

Phytoestrogenic compounds in alfalfa sprout (Medicago sativa) beyond coumestrol.

Coumestrol has long been known as the phytoestrogenic compound in alfalfa. However, it has been demonstrated that the ethyl acetate extract of alfalfa sprout (AEA) attenuated the disease severity and increased survival and life span of autoimmune-prone MRL-lpr/lpr mice. Coumestrol, on the contrary, decreased the survival. This study thus aimed to isolate and identify phytoestrogenic compounds other than coumestrol in AEA. AEA was fractionated and separated by successive silica gel chromatography and preparative HPLC. The activity of collected fractions was tracked by a transactivation assay for ERα and ERß, respectively. In addition to coumestrol, liquiritigenin, isoliquiritigenin, loliolide, and (4S,6S)- and (4R,6S)-4-hydroxy-6-pentadecyltetrahydropyr-2-one were isolated and chemically identified. Except for loliolide, these compounds showed higher transactivation via ERß than via ERα. The maximal activation via ERα of coumestrol reached 80% that of 1 nM 17ß-estradiol (E(2)), whereas the activations of the remaining five compounds as well as AEA ranged from 8 to 49%. In addition, isoliquiritigenin, loliolide, and (4S,6S)- and (4R,6S)-4-hydroxy-6-pentadecyltetrahydropyr-2-one, but not coumestrol, preferentially inhibited 1 nM E(2) induced ERα activation, compared to that ERß activation. The selectivity of these phytoestrogens might account for the difference between the effects of AEA and coumestrol in autoimmune-prone MRL-lpr/lpr mice observed previously.

Phenolic compounds from Pueraria lobata protect PC12 cells against Aß-induced toxicity.

Bioassay-guided fractionation of the EtOAc-soluble extract of Pueraria lobata based on the inhibition of Aß-induced toxicity in PC12 cells resulted in the isolation of four known active compounds, genistein (8), biochanin A (9), sissotrin (10), and puerol B (11). Of these, genistein (8) and biochanin A (9) exhibited potent neuroprotective effects with ED(50) values of 33.7 and 27.8 µM, respectively. In addition, a new coumestan, 2-(α,α-dimethylallyl)coumestrol (1) was isolated and characterized, but proved to be inactive, as were additional seven known compounds. The structure of new compound 1 was determined using spectroscopic techniques.

Puerariafuran, a new inhibitor of advanced glycation end products (AGEs) isolated from the roots of Pueraria lobata.

A new 2-arylbenzofuran, puerariafuran (1), as well as three known compounds, coumestrol (2), daidzein (3), and genistein (4), were isolated from a MeOH extract of the roots of Pueraria lobata as active constituents, using an in vitro bioassay based on the inhibition of advanced glycation end products (AGEs) to monitor chromatographic fractionation. The structure of 1 was determined by spectroscopic data interpretation, particularly by extensive 1D and 2D NMR studies. All the isolates (1-4) were evaluated for the inhibitory activity on AGEs formation in vitro.

[Estrogenic activity of some lucerne varieties]. / Vurkhu estrogennati aktivnost na niakoi sortove liutserna.

Studies was the estrogenic activity of lucerne--the local population Dounavka, the zonated French variety Du Puits, the promising Bulgarian variety. Pleven 1, the population Boinitsa, and the French variety Du Poitou. The estrogenic activity was determined by the biologic method based on the increase in the uterus weight of infantile mice after treatment with estrogens. Paper chromatography tests were also carried out to establish the presence of genestein and cumestrol. The study comprised three consecutive years, the extent of estrogenic activity being dependent on the amount of annual precipitations and the yields of green mass and dry matter. The study revealed that there were variations in the estrogenic activity of the investigated varieties and populations of lucerne within a wide range depending on the year of use and the green mass and dry matter obtained. High was it in the local population Dounavka, the French variety Du Poitou, and the Bulgarian variety Pleven 1. Comparatively lower was the estrogenic activity in Du Puits, and the local population Boinitsa. In all varieties and populations studied genestein was found in the first swath, and cumestrol--in the second swath. The remaining swaths showed differences in the content of genestein and cumestrol in the individual varieties and populations.