5-Hydroxymethylfurfural, an antioxidant agent from Alpinia oxyphylla Miq. improves cognitive impairment in Aβ1–42 mouse model of Alzheimer's disease

An overview of chemical constituents from Alpinia species in the last six decades

Alpinia species is one of the most important genera of the Zingiberaceae family. Up to 2015, 544 compounds with various bioactivities were isolated, the major components are diarylheptanoids (143) and sesquiterpenoids (132).

Phytochemical Composition and Biological Activities of Selected Wild Berries (Rubus moluccanus L., R. fraxinifolius Poir., and R. alpestris Blume)

Berries, from the genus Rubus, are among the vital components in a healthy diet. In this study, 80% methanol extracts from the three wild Rubus species (Rubus moluccanus L., Rubus fraxinifolius Poir., and Rubus alpestris Blume) were evaluated for their phytochemical contents (total phenolics, flavonoid, anthocyanin, and carotenoid content), antioxidant (DPPH, FRAP, and ABTS assays), antiacetylcholinesterase, and antibacterial activities. GC-MS was used for quantification of naturally occurring phytochemicals. The results showed that R. alpestris contained the highest total phenolic [24.25 ± 0.1 mg gallic acid equivalent (GAE)/g] and carotenoid content [21.86 ± 0.63 mg β-carotene equivalents (BC)/g], as well as the highest DPPH scavenging and FRAP activities. The highest total flavonoid [18.17 ± 0.20 mg catechin equivalents (CE)/g] and anthocyanin content [36.96 ± 0.39 mg cyanidin-3-glucoside equivalents (c-3-gE)/g] have been shown by R. moluccanus. For antibacterial assays, R. moluccanus and R. alpestris extracts showed mild inhibition towards Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Anticholinesterase activity for all extracts was in the range of 23-26%. The GC-MS analysis revealed the presence of at least 12, 21, and 7 different organic compounds in 80% methanol extracts of R. alpestris, R. moluccanus, and R. fraxinifolius, respectively, which might contribute to the bioactivity.

Upregulation effects of Tanshinone IIA on the expressions of NeuN, Nissl body, and IκB and downregulation effects on the expressions of GFAP and NF-κB in the brain tissues of rat models of Alzheimer's disease

This study aimed to observe the effects of Tanshinone IIA(Tan IIA) treatment on the expression levels of brain tissue NeuN, Nissl body, IκB, GFAP and NF-κB in Alzheimer's disease (AD) rats to explore the possible anti-inflammatory and neuroprotective mechanisms of Tan IIA. Thirty healthy male Sprague-Dawley rats were randomized into three groups: Sham group, AD+vehicle control group, and AD+Tan IIA group. The models of AD were established by injecting Aβ1-42 into the hippocampus of rats. Tagged position and the expression levels of Aβ1-42 were observed by immunohistochemistry staining to prove the success of the model of AD. Brain tissues of all groups were collected after Tan IIA treatment and paraffin sections were prepared to assess pathological changes and expression levels of GFAP, IκB and NF-κB by both immunohistochemistry and western blotting. After Aβ1-42 injection, the expression levels of GFAP and NF-κB were significantly stronger in the AD+vehicle control group than those in the AD+Tan IIA group and the sham group (P<0.05), the IκB expression level and the number of neurons and Nissl bodies of AD+vehicle control group was reduced compared with the sham or the AD+Tan IIA group (P<0.05). In conclusion, Aβ induces a cerebral tissue inflammation reaction. Tan IIA treatment can suppress the proliferation of astrocytes in an AD model, lower the level of NF-κB, and increase the level of NeuN, Nissl body, IκB, thus exerting anti-inflammatory and neuroprotective effects.

Fermented Sipjeondaebo-tang Alleviates Memory Deficits and Loss of Hippocampal Neurogenesis in Scopolamine-induced Amnesia in Mice

We investigated the anti-amnesic effects of SJ and fermented SJ (FSJ) on scopolamine (SCO)-induced amnesia mouse model. Mice were orally co-treated with SJ or FSJ (125, 250, and 500 mg/kg) and SCO (1 mg/kg), which was injected intraperitoneally for 14 days. SCO decreased the step-through latency and prolonged latency time to find the hidden platform in the passive avoidance test and Morris water maze test, respectively, and both SCO effects were ameliorated by FSJ treatment. FSJ was discovered to promote hippocampal neurogenesis during SCO treatment by increasing proliferation and survival of BrdU-positive cells, immature/mature neurons. In the hippocampus of SCO, oxidative stress and the activity of acetylcholinesterase were elevated, whereas the levels of acetylcholine and choline acetyltransferase were diminished; however, all of these alterations were attenuated by FSJ-treatment. The alterations in brain-derived neurotrophic factor, phosphorylated cAMP response element-binding protein, and phosphorylated Akt that occurred following SCO treatment were protected by FSJ administration. Therefore, our findings are the first to suggest that FSJ may be a promising therapeutic drug for the treatment of amnesia and aging-related or neurodegenerative disease-related memory impairment. Furthermore, the molecular mechanism by which FSJ exerts its effects may involve modulation of the cholinergic system and BDNF/CREB/Akt pathway.

The influence of common free radicals and antioxidants on development of Alzheimer's Disease

Alzheimer's Disease (AD) is one of the most important neurodegenerative disorders in the 21st century for the continually aging population. Despite an increasing number of patients, there are only few drugs to treat the disease. Numerous studies have shown several causes of the disorder, one of the most important being oxidative stress. Oxidative stress is connected with a disturbance between the levels of free radicals and antioxidants in organisms. Solutions to this problem are antioxidants, which counteract the negative impact of the reactive molecules. Unfortunately, the currently available drugs against AD do not exhibit activity toward these structures. Due to the fact that natural substances are extremely significant in new drug development, numerous studies are focused on substances which exhibit a few activities including antioxidants and other anti-AD behaviors. This review article presents the most important studies connected with the influence of free radicals on development of AD and antioxidants as potential drugs toward AD.

Triptolide attenuated injury via inhibiting oxidative stress in Amyloid-Beta25-35-treated differentiated PC12 cells

BACKGROUND

Recently, an abnormal deposition of Amyloid-Beta (Aβ) was considered the primary cause of the pathogenesis of Alzheimer's disease (AD). And how to inhibit the cytotoxicity is considered an important target for the treatment of AD. Triptolide (TP), a purified diterpenoid from the herb Tripterygium wilfordii Hook.f. (TWHF), has potential neuroprotective effects pertinent to disease of the nervous system. However, whether triptolide and its specific mechanisms have protective functions in differentiated PC12 cells treated with Aβ25-35 remain unclear.

AIMS

The purpose is to investigate the protective functions of triptolide in Aβ25-35-stimulated differentiated PC12 cells.

MAIN METHODS

In the study, we use 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) assay, flow cytometry assay, immunohistochemical staining and Western blot to observe the effects of triptolide on cytotoxicity induced by Aβ25-35 and its mechanism of oxidative stress.

KEY FINDINGS

The result of MTT and LDH assay indicates that triptolide protected PC12 cells against Aβ25-35-induced cytotoxicity. The flow cytometry assay shows that triptolide attenuated Aβ25-35-induced apoptosis in differentiated PC12 cells. Meanwhile, the results give a clear indication that triptolide could downregulate generation of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and malondialdehyde (MDA) induced by Aβ25-35. The apoptotic process triggered by triptolide involved the up-regulation of the activity of superoxide dismutase (SOD).

SIGNIFICANCE

The results suggest that triptolide may serve as an important role in the inhibition of the cell apoptosis induced by Aβ and the decreased oxidative stress is a key mechanism in the protective effect of triptolide in AD.

Garcinia dulcis Fruit Extract Induced Cytotoxicity and Apoptosis in HepG2 Liver Cancer Cell Line

Garcinia dulcis or locally known in Malaysia as “mundu” belongs to the family of Clusiaceae. The study was conducted to investigate the anticancer potential of different parts of G. dulcis fruit extracts and their possible mechanism of action in HepG2 liver cancer cell line. MTT assay showed that the peel, flesh, and seed extracts of G. dulcis induced cytotoxicity in HepG2 cell line with IC₅₀ values of 46.33 ± 4.51, 38.33 ± 3.51, and 7.5 ± 2.52 µg/mL, respectively. The flesh extract of G. dulcis induced cell cycle arrest at sub-G₁ (apoptosis) phase in a time-dependent manner. Staining with Annexin V-FITC and propidium iodide showed that 41.2% of the cell population underwent apoptosis after 72 hours of exposure of the HepG2 cell line to G. dulcis flesh extract. Caspase-3 has been shown to be activated which finally leads to the death of HepG2 cell (apoptosis). GC-MS analysis showed that the highest percentage of compound identified in the extract of G. dulcis flesh was hydroxymethylfurfural and 3-methyl-2,5-furandione, together with xanthones and flavonoids (based on literature), could synergistically contribute to the observed effects. This finding suggested that the flesh extract of G. dulcis has its own potential as cancer chemotherapeutic agent against liver cancer cell.