Anti-inflammatory, Anti-glycation, Anti-tyrosinase and CDK4 Inhibitory Activities of Alaternin (=7-Hydroxyemodin)

The aim of this study was to anatomize the therapeutic potential of alaternin (=7-hydroxyemodin) against inflammation, advanced glycation end products (AGEs) formation, tyrosinase, and two cyclin-dependent kinases (CDKs), CDK2 and CDK4, and compare its potency with emodin. Alaternin showed lower cytotoxicity and higher dose-dependent inhibition against lipopolysaccharide (LPS) induced nitric oxide (NO) production with half maximal inhibitory concentration (IC 50 ) of 18.68 µM. Similarly, alaternin efficaciously inhibited biotransformation of fluorescent AGEs and amyloid cross-β structure on the bovine serum albumin (BSA)-glucose-fructose system, five times more than emodin. Interestingly, alaternin also showed selective activity against CDK4 at 170 µM, whereas emodin inhibited both CDK2 and CDK4 at a concentration of 17 and 380 µM respectively. In addition, alaternin showed dose-dependent inhibitory activity against mushroom tyrosinase with inhibition percentage of 35.84 % at 400 µM. Altogether, alaternin with pronounced inhibition against inflammatory mediator (NO), glycated products formation, and targeted inhibition towards CDK4 receptor can be taken as an important candidate to target multiple diseases.

Anti-inflammatory, Anti-glycation, Anti-tyrosinase and CDK4 Inhibitory Activities of Alaternin (=7-Hydroxyemodin)

The aim of this study was to anatomize the therapeutic potential of alaternin (=7-hydroxyemodin) against inflammation, advanced glycation end products (AGEs) formation, tyrosinase, and two cyclin-dependent kinases (CDKs), CDK2 and CDK4, and compare its potency with emodin. Alaternin showed lower cytotoxicity and higher dose-dependent inhibition against lipopolysaccharide (LPS) induced nitric oxide (NO) production with half maximal inhibitory concentration (IC 50 ) of 18.68 µM. Similarly, alaternin efficaciously inhibited biotransformation of fluorescent AGEs and amyloid cross-β structure on the bovine serum albumin (BSA)-glucose-fructose system, five times more than emodin. Interestingly, alaternin also showed selective activity against CDK4 at 170 µM, whereas emodin inhibited both CDK2 and CDK4 at a concentration of 17 and 380 µM respectively. In addition, alaternin showed dose-dependent inhibitory activity against mushroom tyrosinase with inhibition percentage of 35.84 % at 400 µM. Altogether, alaternin with pronounced inhibition against inflammatory mediator (NO), glycated products formation, and targeted inhibition towards CDK4 receptor can be taken as an important candidate to target multiple diseases.

Isolation and Identification of Bioactive Compounds from the Tuber of Brassica oleracea var. gongylodes

Brassica oleracea var. gongylodes (red kohlrabi) is a biennial herbaceous vegetable whose edible bulbotuber-like stem and leaves are consumed globally. Sliced red kohlrabi tubers were extracted using methanol and the concentrated extract was partitioned successively with dichloromethane (CH 2 Cl 2), ethyl acetate (EtOAc), n-butanol (n-BuOH) and water (H 2 O). Repeated column chromatography of EtOAc fraction through silica, sephadex LH-20 and RP-18 gel led to isolation of eleven compounds of which compound 1 was a new glycosylated indole alkaloid derivative, 1-methoxyindole 3-carboxylic acid 6-O-β-D-glucopyranoside. Others were known compounds namely, β-sitosterol glucoside (4), 5-hydroxymethyl-2-furaldehyde (5), methyl-1-thio-βD-glucopyranosyl disulfide (6), 5-hydroxy-2-pyridinemethanol (7), (3S,4R)-2-deoxyribonolactone (8), n-butyl-βD-fructopyranoside (9), uridine (10) and three fructose derivatives, D-tagatose (11), β-D-fructofuranose (12) and β-D-fructopyranose (13). Similarly, isolation from CH 2Cl 2 fraction gave two known indole alkaloids, indole 3-acetonitrile (2) and N-methoxyindole 3-acetonitrile (3). The structure elucidation and identification of these compounds were conducted with the help of 13 C and 1 H NMR, HMBC, HMQC, EIMS, HR-ESIMS and IR spectroscopic data, and TLC plate spots visualization. Compounds 2, 3, 4, 5, 6, 7, 8 and 9 are noted to occur in kohlrabi for the first time. Different bioactivities of these isolated compounds have been reported in literature.

Ethnobotany, Phytochemistry, and Pharmacology of Angelica decursiva Fr. et Sav

Angelica decursiva Fr. et Sav. (Umbelliferae) has traditionally been used to treat different diseases due to its antitussive, analgesic, and antipyretic activities. It is also a remedy for thick phlegm, asthma, and upper respiratory infections. Recently, the leaf of A. decursiva has been consumed as salad without showing any toxicity. This plant is a rich in different types of coumarin derivatives, including dihydroxanthyletin, psoralen, dihydropsoralen, hydroxycoumarin, and dihydropyran. Its crude extracts and pure constituents possess anti-inflammatory, anti-diabetic, anti-Alzheimer disease, anti-hypertension, anti-cancer, antioxidant, anthelmintic, preventing cerebral stroke, and neuroprotective activities. This valuable herb needs to be further studied and developed not only to treat these human diseases, but also to improve human health. This review provides an overview of current knowledge of A. decursiva metabolites and their biological activities to prioritize future studies.

Isolation and Quantitative Analysis of BACE1 Inhibitory Compounds from Cirsium maackii Flower

The purpose of our study was to evaluate anti-AD potential of Cirsium maackii flowers. MeOH extract, CH2Cl2, EtOAc, and n-BuOH fraction of this flower notably inhibited BACE1 (IC₅₀ = 76.47 ± 1.66, 22.98 ± 1.45, 8.65 ± 0.63, and 72.47 ± 3.04 µg/mL, respectively). β-amyrenone (49.70 mg) (1), lupeol acetate (1.43 g) (2), lupeol (1.22 g) (3), lupenone (23.70 mg) (4), β-sitosterol (1.01 g) (6), and β-sitosterol glucoside (13.00 mg) (7) from CH₂Cl₂, apigenin (100.20 mg) (8), luteolin (19.00 mg) (9), apigenin 7-O-glucuronide methyl ester (21.30 mg) (14), and tracheloside (53.70 mg) (5) from EtOAc, apigenin 5-O-glucoside (11.00 mg) (10), luteolin 5-O-glucoside (11.00 mg) (11) and apigenin 7-O-glucuronide (91.00 mg) (12) from n-BuOH, and luteolin 7-O-glucuronide (22.00 mg) (13) from H₂O fraction were isolated. HPLC showed high levels of 8, 9 and 12 in MeOH extract (33.07 ± 0.07, 31. 44 ± 0.17 and 16.89 ± 0.33 mg/g, respectively), EtOAc (161.01 ± 1.78, 96.93 ± 0.34 and 73.38 ± 0.06 mg/g, respectively), and n-BuOH fraction (32.18 ± 0.33, 44.31 ± 0.32 and 105.94 ± 0.36 mg/g, respectively). Since, 3 and 9 are well-known BACE1 inhibitors, the anti-AD activity of C. maackii flower might be attributable to their presence.

Isolation of Flavonoid Glycosides with Cholinesterase Inhibition Activity and Quantification from Stachys japonica

The three flavone glycosides, 4′-O-methylisoscutellarein 7-O-(6‴-O-acetyl)-β-D-allopyranosyl(1→2)-β-D-glucopyranoside (1), isoscutellarein 7-O-(6‴-O-acetyl)-β-D-allopyranosyl(1→2)-β-D-glucopyranoside (3), and isoscutellarein 7-O-β-D-allopyranosyl(1→2)-β-D-glucopyranoside (4) in addition to a flavonol glycoside, kaempferol 3-O-β-D-glucopyranoside (astragalin, 2), were isolated from Stachys japonica (Lamiaceae). In cholinesterase inhibition assay, compound 1 significantly inhibited aceylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (IC₅₀s, 39.94 µg/ml for AChE and 86.98 µg/ml for BChE). The content of isolated compounds were evaluated in this plant extract by HPLC analysis. Our experimental results suggest that the flavonoid glycosides of S. japonica could prevent the memory impairment of Alzheimer's disease.

Anti-inflammatory Potential of Artemisia capillaris and Its Constituents in LPS-induced RAW264.7 Cells

Artemisia capillaris has been widely used as an alternative therapy for treating obesity and atopic dermatitis. It has been used as a hepatoprotactant. It is also used for ameliorating inflammatory reactions. Although there are several investigations on other Artemisia species, there is no systematic study describing the role of A. capillaris MeOH extract, its solvent soluble fractions, or derived anti-inflammatory principal components in regulating inflammatory conditions. Therefore, the objective of this study was to elucidate anti-inflammatory mechanisms of A. capillaris. Results revealed that MeOH extract of A. capillaris could decrease LPS-stimulated NO secretion. Of tested fractions, CH₂Cl₂, EtOAc, and n-BuOH strongly inhibited NO release from RAW264.7 cells. Bioactive mediators derived from CH₂Cl₂ and n-BuOH fractions elicited potent anti-inflammatory actions and strikingly abrogated LPS-triggered NO accumulation in RAW264.7 cells. Of particular interest, capillin and isoscopoletin possessed the most potent NO suppressive effects. Western blot analysis validated the molecular mechanism of NO inhibition and showed that capillin and isoscopoletin significantly down-regulated iNOS and COX-2 protein expression. Taken together, our results provide the first evidence that MeOH extract, CH₂Cl₂, EtOAc, and n-BuOH fractions from A. capillaris and its derived lead candidates can potently suppress inflammatory responses in macrophages by hampering NO release and down-regulating iNOS and COX-2 signaling.

Comparative molecular docking studies of lupeol and lupenone isolated from Pueraria lobata that inhibits BACE1: Probable remedies for Alzheimer's disease

Objective To discover lead lupane triterpenoid's potential isolated from Pueraria lobata roots against β-site amyloid precursor protein cleaving enzyme 1 (BACE1), which serve as a rate limiting step in amyloid beta (Aβ) production altering the course of Alzheimer's disease. In addition, enzyme kinetics study and molecular docking were conducted to establish the inhibition type and structure activity relationship. Methods A systematic study of 70% ethanolic P. lobata root extract was employed to identify its BACE1 inhibitory potential. Further, BACE1 inhibitory potential of two lupane terpenoids, yielded from ethanolic extract, was assessed. In order to determine their inhibition mode, Lineweaver–Burk plots and Michaelis–Menten model for BACE1 was performed. AutoDock 4.2 program in addition determined the molecular interaction of BACE1 with isolated terpenoids. Results Considering the inhibitory potential of 70% ethanolic extract of P. lobata against BACE1 (IC

Comparative molecular docking studies of lupeol and lupenone isolated from Pueraria lobata that inhibits BACE1: Probable remedies for Alzheimer's disease

OBJECTIVE@#To discover lead lupane triterpenoid's potential isolated from Pueraria lobata roots against β-site amyloid precursor protein cleaving enzyme 1 (BACE1), which serve as a rate limiting step in amyloid beta (Aβ) production altering the course of Alzheimer's disease. In addition, enzyme kinetics study and molecular docking were conducted to establish the inhibition type and structure activity relationship.@*METHODS@#A systematic study of 70% ethanolic P. lobata root extract was employed to identify its BACE1 inhibitory potential. Further, BACE1 inhibitory potential of two lupane terpenoids, yielded from ethanolic extract, was assessed. In order to determine their inhibition mode, Lineweaver-Burk plots and Michaelis-Menten model for BACE1 was performed. AutoDock 4.2 program in addition determined the molecular interaction of BACE1 with isolated terpenoids.@*RESULTS@#Considering the inhibitory potential of 70% ethanolic extract of P. lobata against BACE1 (IC = 80.35 μg/mL), lupeol and lupenone were subsequently isolated and exhibited notable or moderate BACE1 inhibitory activity with IC values of 5.12 and 62.98 μmol/L, respectively, as compared to the positive control quercetin (IC = 21.28 μmol/L). The enzyme kinetics study enabled us to identify both compounds as competitive inhibitors, where lupeol displayed a very potent inhibition against BACE1 with low inhibition constant (K) value of 1.43 μmol/L, signifying greater binding affinity. In order to understand the binding mechanism and structure-activity relationship of two triterpene-based BACE1 inhibitors, we employed computer aided docking studies which evidently revealed that hydroxyl group of lupeol formed two hydrogen bonds with the ASP32 (catalytic aspartic residue) and SER35 residues of BACE1 with the binding energy of (-8.2 kcal/mol), while the ketone group of lupenone did not form any hydrogen bonds with BACE1 giving evidence for less binding affinity. These results in turn have predicted the dependence of the inhibitory activity in the presence of hydroxyl group which has provided a new basis for BACE1 blockade.@*CONCLUSIONS@#Our results have successfully explored the molecular mechanism of lupane triterpenoids via BACE1 inhibition, suggesting that lupeol in particular could be utilized as a useful therapeutic and preventive agent to mitigate Alzheimer's disease.

HPLC analysis of Phenolic Substances and Anti-Alzheimer's Activity of Korean Quercus Species

This study aimed to establish the quantitative method to analyze the content of peroxynitrite-scavengers belonging to polyphenols in six Korean Quercus species (Quercus mongolica, Q. dentata, Q. acutissima, Q. alienta, Q. serrata, and Q. variabilis) by HPLC. The twelve peroxynitrite-scavengers, flavanols (catechins: (+)-catechin, (−)-epicatechin, and (−)-epigallocatechin), flavonols (kaempferol and quercetin), flavonol glycosides (astragalin, quercitrin, and isoquercitrin), flavonol acylated glycosides (astragalin 6″-gallate and isoquercitrin 6″-gallate), gallic acid and its dimer (ellagic acid) were analyzed by HPLC. Further, anti-Alzheimer's activity was assayed in a passive avoidance testusing mice by measuring the retention latency (sec), the concentration of acetylcholine (ACh), and acetylcholinesterase (AChE) activity. Simultaneous analysis of the extracts of the six Quercus leaves was achieved on a Capcell C18 column (5 µm, 250 mm × 4.6 mm i.d.) with a gradient elution of 0.05% HAc and 0.05% HAc in CH₃CN. In the extract of Q. mongolica leaves, the content of gallic acid (32.53 mg/g), (+)-catechin (28.78 mg/g), (−)-epicatehin (22.03 mg/g), astragalin 6″-gallate (20.94 mg/g), and isoquercitrin 6″-gallate (44.11 mg/g) and peroxynitrite-scavenging activity (IC₅₀, 0.831 µg/ml) were high. This extract delayed the retention latency and inhibited acetylcholinesterase activity in scopolamine-induced memory impairment of mice, suggesting that it has anti-Alzheimer's activity.