Therapeutic Potential and Mechanisms of Novel Simple O-Substituted Isoflavones against Cerebral Ischemia Reperfusion.

Isoflavones have been widely studied and have attracted extensive attention in fields ranging from chemotaxonomy and plant physiology to human nutrition and medicine. Isoflavones are often divided into three subgroups: simple O-substituted derivatives, prenylated derivatives, and glycosides. Simple O-substituted isoflavones and their glycosides, such as daidzein (daidzin), genistein (genistin), glycitein (glycitin), biochanin A (astroside), and formononetin (ononin), are the most common ingredients in legumes and are considered as phytoestrogens for daily dietary hormone replacement therapy due to their structural similarity to 17-ß-estradiol. On the basis of the known estrogen-like potency, these above isoflavones possess multiple pharmacological activities such as antioxidant, anti-inflammatory, anticancer, anti-angiogenetic, hepatoprotective, antidiabetic, antilipidemic, anti-osteoporotic, and neuroprotective activities. However, there are very few review studies on the protective effects of these novel isoflavones and their related compounds in cerebral ischemia reperfusion. This review primarily focuses on the biosynthesis, metabolism, and neuroprotective mechanism of these aforementioned novel isoflavones in cerebral ischemia reperfusion. From these published works in in vitro and in vivo studies, simple O-substituted isoflavones could serve as promising therapeutic compounds for the prevention and treatment of cerebral ischemia reperfusion via their estrogenic receptor properties and neuron-modulatory, antioxidant, anti-inflammatory, and anti-apoptotic effects. The detailed mechanism of the protective effects of simple O-substituted isoflavones against cerebral ischemia reperfusion might be related to the PI3K/AKT/ERK/mTOR or GSK-3ß pathway, eNOS/Keap1/Nrf-2/HO-1 pathway, TLRs/TIRAP/MyD88/NFκ-B pathway, and Bcl-2-regulated anti-apoptotic pathway. However, clinical trials are needed to verify their potential on cerebral ischemia reperfusion because past studies were conducted with rodents and prophylactic administration.

Insulin sensitizer and antihyperlipidemic effects of Cajanus cajan (L.) millsp. root in methylglyoxal-induced diabetic rats.

Cajanus cajan (L.) Millsp., known as pigeon pea, is one of the major grain legume crops of the tropical world. It recognizes as an ethnomedicine to possess various functions, such as helping in healing wound and cancer therapy. We investigated whether 95% ethanol extracts from C. cajan root (EECR) protect against methylglyoxal (MGO)-induced insulin resistance (IR) and hyperlipidemia in male Wistar rats and explored its possible mechanisms. The hypoglycemic potential of EECR was evaluated using α-amylase, α-glucosidase activities, and advanced glycation end products (AGEs) formation. For in vivo study, the rats were divided into six groups and orally supplemented with MGO except for Group 1 (controls). Group 2 was supplemented with MGO only, Group 3: MGO + metformin, Group 4: MGO + Low dose-EECR (L-EECR; 10 mg/kg bw), Group 5: MGO + Middle dose-EECR (M-EECR; 50 mg/kg bw), and Group 6: MGO + High dose-EECR (H-EECR; 100 mg/kg bw). EECR possessed good inhibition of α-glucosidase, α-amylase activities, and AGEs formation (IC50 = 0.12, 0.32, and 0.50 mg/mL), respectively. MGO significantly increased serum levels of blood glucose (GLU), glycosylated hemoglobin, homeostasis model assessment of IR, AGEs, lipid biochemical values, and atherogenic index, whereas EECR decreased these levels in a dose-dependent manner. EECR can also act as an insulin sensitizer, which significantly decreased (47%, P < 0.05) the blood GLU levels after intraperitoneal injection of insulin in the insulin tolerance tests. The hypoglycemic and antihyperlipidemic mechanisms of EECR are likely through several possible pathways including the inhibition of carbohydrate-hydrolyzing enzymes (α-glucosidase and α-amylase) and the enhancement of MGO-trapping effects on inhibition of AGEs formation.

Effects of Cajanus cajan (L.) millsp. roots extracts on the antioxidant and anti-inflammatory activities.

Cajanus cajan (L.) Millsp., also named pigeon pea, is widely grown in the tropics and the subtropics. C. cajan roots (CR) and ribs stewed in hot water have been used as a traditional medicine in various cultures to treat diabetes. The purpose of this study was to determine the functional components of hot water (WCR) and 50%, 95% ethanol extracts (EECR50 and EECR95) from CR, then evaluating their antioxidant and anti-inflammatory effects. The results indicated that EECR95 had higher polyphenol, especially the isoflavones (e.x. daidzein, genistein, and cajanol) than those of the other extracts, and it also exhibited the most potent anti-oxidative activities by in vitro antioxidant assay. In the lipopolysaccharide-stimulated RAW 264.7 cells, we found that EECR95 significantly decreased intracellular reactive oxygen species and significantly enhanced the activities of superoxide dismutase and catalase. Mechanism studies showed that EECR95 mainly activated nuclear factor (NF) erythroid 2-related factor 2/antioxidant protein heme oxygenase-1 and inhibited nuclear factor kappa B (NF-κB) signaling pathway, and thus exhibited antioxidant and anti-inflammatory effects. Overall, this study suggests that CR may have the potential to be developed as a biomedical material and that genistein, which has relatively high uptakes (3.44% for the pure compound and 1.73% for endogenous genistein of EECR95) at 24 h of incubation with RAW 264.7 cells, could be the main active component of CR.

Sophora Tomentosa Extract Prevents MPTP-Induced Parkinsonism in C57BL/6 Mice Via the Inhibition of GSK-3ß Phosphorylation and Oxidative Stress.

Sophora species are used as dietary medicines in aging-associated symptoms. Sophora tomentosa L. (ST) is a native medicinal plant in Southeast Asia; however, there is no pharmacological literature about ST extract. The present study evaluates the antioxidant phytoconstituent contents and radical scavenging capacities of ST extract. The further investigation was to clarify the neuroprotective mechanism of ST extract against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism by assaying the activities of the dopaminergic system and antioxidant defenses, glycogen synthase kinase 3ß (GSK3-ß) phosphorylation, and α-synuclein levels in C57BL/6 mice. The results show that ST extract alleviated the motor deficits in MPTP-induced Parkinsonism with four behavioral tests, including a rearing locomotor, catalepsy test, balance beam walking test, and pole test. ST extract reversed the number of tyrosine hydroxylase (TH)-positive neurons in substantia nigra (SN) that had decreased by MPTP. ST extract also restored the decreased levels of dopamine and the expression of tyrosine hydroxylase (TH) in the striatum. Furthermore, ST extract restored the levels of glutathione (GSH) and the activities of antioxidant enzymes, and decreased the elevated levels of malondialdehyde (MDA) in mouse striatum. ST extract also decreased α-synuclein overexpression and GSK-3ß phosphorylation in mouse striatum. In vitro, ST extract exerted higher 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacities through its higher phenolic contents, especially protocatechuic acid and epicatechin. These results suggest that ST extract has the potential to counteract MPTP-induced motor deficit. The neuroprotective mechanism of ST extract against MPTP-induced Parkinsonism might be related to decreasing GSK-3ß phosphorylation and restoring the activities of striatal antioxidant defenses to restore the nigrostriatal dopaminergic function and decrease α-synuclein accumulation.

Aqueous Extract of Davallia mariesii Attenuates 6-Hydroxydopamine-Induced Oxidative Damage and Apoptosis in B35 Cells Through Inhibition of Caspase Cascade and Activation of PI3K/AKT/GSK-3ß Pathway.

The medicinal ferns of Polydiaceae and Davalliaceae species are called "Gusuibu" by Chinese physicians and used as antiaging dietary medicines. Our previous report revealed that Drynaria fortunei (Polydiaceae) protected against 6-hydroxydopamine (6-OHDA)-induced oxidative damage via the PI3K/AKT pathway in B35 neuroblastoma cells. The present study compares the antioxidant phytoconstituent contents and radical scavenging capacities of five Davalliaceae species. The further aim was to clarify the protective mechanism of Davallia mariesii (DM) against 6-OHDA-induced oxidative damage and apoptosis in B35 cells. The results show that Araiostegia perdurans (AP) and DM extracts have better radical scavenging capacities against 1,1-diphenyl-2-picryhydrazyl (DPPH) and reactive oxygen species (ROS) than other Davalliaceae species. However, only DM extract inhibited 6-OHDA autoxidation under cell-free systems and increased cell viability, compared to B35 cells solely exposed to 6-OHDA. DM extract decreased apoptosis and restored mitochondrial expression in 6-OHDA-treated B35 cells. Additional data indicated that DM extract decreased intracellular ROS and nitric oxide levels generated by 6-OHDA exposure. DM extract also restored glutathione (GSH) levels and the activities of glutathione peroxidase and reductase, and then decreased the elevated malondialdehyde (MDA) levels. Finally, DM extract regulated the protein expression of the caspase cascade and PI3K/AKT/GSK-3ß pathways. These results suggest that the protective mechanism of DM extract against 6-OHDA-induced oxidative damage and apoptosis might be related to its radical scavenging capacity, maintaining the mitochondrial function to inhibit the Bcl-2/caspase cascade pathway and activating intracellular antioxidant defenses (GSH recycling, HO-1 and NQO-1) by modulating the activation of the PI3K/AKT/GSK-3ß pathway.

Ferulic acid reverses the cognitive dysfunction caused by amyloid ß peptide 1-40 through anti-oxidant activity and cholinergic activation in rats.

Cholinergic dysfunction and oxidation stress are the dominant mechanisms of memory deficit in Alzheimer's disease (AD). This study describes how ferulic acid (FA) ameliorates cognitive deficits induced by mecamylamine (MECA), scopolamine (SCOP), central acetylcholinergic neurotoxin ethylcholine mustard aziridinium ion (AF64A) and amyloid ß peptide (Aß1-40). This study also elucidates the role of anti-oxidant enzymes and cholinergic marker acetylcholinesterase (AChE) in the reversal of FA from Aß1-40-induced cognitive deficits in rats. At 100 mg/kg, FA attenuated impairment induced by MECA and SCOP plus MECA; however, this improvement was not blocked by the peripheral muscarinic receptor antagonist scopolamine methylbromide (M-SCOP). At 100 and 300 mg/kg, FA also attenuated the impairment of inhibitory passive avoidance induced by AF64A. Further, FA attenuated the performance impairment and memory deficit induced by Aß1-40 in rats, as did vitamin E/C. FA reversed the deterioration of superoxide dismutase (SOD) and AChE activities, and the glutathione disulfide (GSSG) and glutathione (GSH) levels in the cortex and hippocampus. Vitamin E/C only selectively reversed deterioration in the hippocampus. We suggest that FA reduced the progression of cognitive deficits by activating central muscarinic and nicotinic receptors and anti-oxidant enzymes.

Effector mechanism of magnolol-induced apoptosis in human lung squamous carcinoma CH27 cells.

1 Magnolol, an active component isolated from the root and stem bark of Magnolia officinalis, has been reported to exhibit antitumour effects, but little is known about its molecular mechanisms of action. 2 Magnolol inhibited proliferation of human lung squamous carcinoma CH27 cells at low concentrations (10-40 microM), and induced apoptosis at high concentrations (80-100 microM). 3 Treatment with 80 microM magnolol significantly increased the expression of Bad and Bcl-X(S) proteins, whereas it decreased the expression of Bcl-X(L). Overexpression of Bcl-2 protected CH27 cells against magnolol-triggered apoptosis. 4 Magnolol treatment resulted in accumulation of cytosolic cytochrome c and activation of caspase-9 and downstream caspases (caspase-3 and -6). Pretreatment with z-VAD-fmk markedly inhibited magnolol-induced cell death, but did not prevent cytosolic cytochrome c accumulation. 5 Magnolol induced a modest and persistent JNK activation and ERK inactivation in CH27 cells without evident changes in the protein levels. The responsiveness of JNK and ERK to magnolol suggests the involvement of these kinases in the initiation of the apoptosis process. 6 These results indicate that regulation of the Bcl-2 family, accumulation of cytosolic cytochrome c, and activation of caspase-9 and caspase-3 may be the effector mechanisms of magnolol-induced apoptosis.