Protective effects of organic extracts of Alpinia oxyphylla against hydrogen peroxide-induced cytotoxicity in PC12 cells

Antioxidant Capacity and Protective Effects on H2O2-Induced Oxidative Damage in PC12 Cells of the Active Fraction of Brassica rapa L

Brassica rapa L. (BR), a traditional biennial herb belonging to the Brassica species of Brassicaceae, has been widely used for functions of anti-inflammatory, antitumor, antioxidation, antiaging, and regulation of immunity. In this study, antioxidant activity and protective effects on H2O2-induced oxidative damage in PC12 cells of the active fractions of BR were investigated in vitro. Among all active fractions, the ethyl acetate fraction of ethanol extract from BR (BREE-Ea) showed the strongest antioxidant activity. Additionally, it was noted that BREE-Ea and n-butyl alcohol fraction of ethanol extract from BR (BREE-Ba) both have protective effects in oxidatively damaged PC12 cells, while BREE-Ea displayed the best protective effect in all determined experimental doses. Furthermore, flow cytometry (DCFH-DA staining) analysis indicated that BREE-Ea could reduce the H2O2-induced apoptosis in PC12 cells by reducing the production of intracellular reactive oxygen species (ROS) and increasing enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Moreover, BREE-Ea could decrease the malondialdehyde (MDA) content and reduce the release of extracellular lactic dehydrogenase (LDH) from H2O2-induced PC12 cells. All these results demonstrate that BREE-Ea has a good antioxidant capacity and protective effect on PC12 cells against apoptosis induced by H2O2 and that it can be used as a good edible antioxidant to improve the body's endogenous antioxidant defense.

Current and future outlook of loaded components in hydrogel composites for the treatment of chronic diabetic ulcers

Due to recalcitrant microangiopathy and chronic infection, traditional treatments do not easily produce satisfactory results for chronic diabetic ulcers. In recent years, due to the advantages of high biocompatibility and modifiability, an increasing number of hydrogel materials have been applied to the treatment of chronic wounds in diabetic patients. Research on composite hydrogels has received increasing attention since loading different components can greatly increase the ability of composite hydrogels to treat chronic diabetic wounds. This review summarizes and details a variety of newly loaded components currently used in hydrogel composites for the treatment of chronic diabetic ulcers, such as polymer/polysaccharides/organic chemicals, stem cells/exosomes/progenitor cells, chelating agents/metal ions, plant extracts, proteins (cytokines/peptides/enzymes) and nucleoside products, and medicines/drugs, to help researchers understand the characteristics of these components in the treatment of diabetic chronic wounds. This review also discusses a number of components that have not yet been applied but have the potential to be loaded into hydrogels, all of which play roles in the biomedical field and may become important loading components in the future. This review provides a "loading component shelf" for researchers of composite hydrogels and a theoretical basis for the future construction of "all-in-one" hydrogels.

Peroxiredoxin 1 alleviates oxygen-glucose deprivation/ reoxygenation injury in N2a cells via suppressing the JNK/caspase-3 pathway

Objectives

Cerebral ischemia/reperfusion (I/R) injury inevitably aggravates the initial cerebral tissue damage following a stroke. Peroxiredoxin 1 (Prdx1) is a representative protein of the endogenous antioxidant enzyme family that regulates several reactive oxygen species (ROS)-dependent signaling pathways, whereas the JNK/caspase-3 proapoptotic pathway has a prominent role during cerebral I/R injury. This study aimed to examine the potential mechanism of Prdx1 in Neuro 2A (N2a) cells following oxygen-glucose deprivation and reoxygenation (OGD/R) injury.

Materials and Methods

N2a cells were exposed to OGD/R to simulate cerebral I/R injury. Prdx1 siRNA transfection and the JNK inhibitor (SP600125) were used to interfere with their relative expressions. CCK-8 assay, flow cytometry, and lactate dehydrogenase (LDH) assay were employed to determine the viability and apoptosis of N2a cells. The intracellular ROS content was assessed using ROS Assay Kit. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analyses were conducted to detect the expression levels of Prdx1, JNK, phosphorylated JNK (p-JNK), and cleaved caspase-3.

Results

Firstly, Prdx1, p-JNK, and cleaved caspase-3 expression were significantly induced in OGD/R-exposed N2a cells. Secondly, the knockdown of Prdx1 inhibited cell viability and increased apoptosis rate, expression of p-JNK, and cleaved caspase-3 expression. Thirdly, SP600125 inhibited the JNK/caspase-3 signaling pathway and mitigated cell injury following OGD/R. Finally, SP600125 partially reversed Prdx1 down-regulation-mediated cleaved caspase-3 activation and OGD/R damage in N2a cells.

Conclusion

Prdx1 alleviates the injury to N2a cells induced by OGD/R via suppressing JNK/caspase-3 pathway, showing promise as a potential therapeutic for cerebral I/R injury.

Neuroprotective Effects of Alpinia oxyphylla Miq against Mitochondria-Related Apoptosis by the Interactions between Upregulated p38 MAPK Signaling and Downregulated JNK Signaling in the Subacute Phase of Cerebral Ischemia-Reperfusion in Rats

Apoptosis in the penumbra region is the major cell death mechanism occurring during ischemia–reperfusion injury’s early phase. Here, we evaluated how the Alpinia oxyphylla Miq (AOM) affects mitochondria-related apoptosis 3 days after transient middle cerebral artery occlusion (MCAo) and examined the mechanisms underlying the regulation of MAPK-mediated mitochondria-related apoptotic signaling in the peri-infarct cortex in rats. The rats were administered the AOM extract intraperitoneally at doses of 0.2[Formula: see text]g/kg (AOM-0.2[Formula: see text]g), 0.4[Formula: see text]g/kg (AOM-0.4[Formula: see text]g), or 0.8[Formula: see text]g/kg (AOM-0.8[Formula: see text]g) at MCAo initiation. The AOM-0.4[Formula: see text]g and AOM-0.8[Formula: see text]g significantly ameliorated apoptotic cell death and considerably downregulated cytochrome c (cyto c) and cleaved caspase-3 immunoreactivity 3 days after reperfusion. Simultaneously, they significantly downregulated cytosolic p-JNK/JNK, cathepsin B/actin, cyto c/actin, Smac/DIABLO/actin, cleaved caspase-3/actin, and AIF/actin and mitochondrial p53/HSP60 and Bax/HSP60 fractions but upregulated cytosolic p-p38 MAPK/p38 MAPK, p-p90RSK/actin, p-Bad/Bad, p-CREB/actin, and XIAP/actin and cytosolic and mitochondrial Bcl-2/Bax and Bcl-xL/Bax fractions in the peri-infarct cortex. Pretreatment with SB203580 — a p38 MAPK inhibitor — completely abrogated the effects of AOM-0.8[Formula: see text]g on the aforementioned protein expression, whereas treatment with SP600125 — a JNK inhibitor — exerted protective effects similar to those of AOM-0.8[Formula: see text]g. Treatment with 0.4 or 0.8[Formula: see text]g/kg AOM has neuroprotective effects against mitochondria-related apoptosis by suppressing cyto c, Smac/DIABLO, and AIF release from the mitochondria to cytosol. The anti-mitochondria related apoptotic effects of the AOM extract are attributable to the interactions between upregulated p38 MAPK/p90RSK-mediated p-Bad and CREB signaling and downregulated JNK/cathepsin B-mediated Bax and p53 signaling in the peri-infarct cortex 3 days after transient MCAo.

Comparative transcriptome analysis of Alpinia oxyphylla Miq. reveals tissue-specific expression of flavonoid biosynthesis genes

BACKGROUND

Alpinia oxyphylla Miq. is an important edible and medicinal herb, and its dried fruits are widely used in traditional herbal medicine. Flavonoids are one of the main chemical compounds in A. oxyphylla; however, the genetic and molecular mechanisms of flavonoid biosynthesis are not well understood. We performed transcriptome analysis in the fruit, root, and leaf tissues of A. oxyphylla to delineate tissue-specific gene expression and metabolic pathways in this medicinal plant.

RESULTS

In all, 8.85, 10.10, 8.68, 6.89, and 8.51 Gb clean data were obtained for early-, middle-, and late-stage fruits, leaves, and roots, respectively. Furthermore, 50,401 unigenes were grouped into functional categories based on four databases, namely Nr (47,745 unigenes), Uniprot (49,685 unigenes), KOG (20,153 unigenes), and KEGG (27,285 unigenes). A total of 3110 differentially expressed genes (DEGs) and five distinct clusters with similar expression patterns were obtained, in which 27 unigenes encoded 13 key enzymes associated with flavonoid biosynthesis. In particular, 9 DEGs were significantly up-regulated in fruits, whereas expression of 11 DEGs were highly up-regulated in roots, compared with those in leaves.

CONCLUSION

The DEGs and metabolic pathway related to flavonoids biosynthesis were identified in root, leaf, and different stages of fruits from A. oxyphylla. These results provide insights into the molecular mechanism of flavonoid biosynthesis in A. oxyphylla and application of genetically engineered varieties of A. oxyphylla.

Pharmacological Mechanisms Underlying the Neuroprotective Effects of Alpinia oxyphylla Miq. on Alzheimer's Disease

Alpinia oxyphylla Miq. (i.e., A. oxyphylla), a traditional Chinese medicine, can exert neuroprotective effects in ameliorating mild cognitive impairment and improving the pathological hallmarks of Alzheimer's disease (AD). Here, 50 active compounds and 164 putative targets were collected and identified with 251 clinically tested AD-associated target proteins using network pharmacology approaches. Based on the Gene Ontology/Kyoto Encyclopedia of Genes and Genomes pathway enrichments, the compound-target-pathway-disease/protein-protein interaction network constructions, and the network topological analysis, we concluded that A. oxyphylla may have neuroprotective effects by regulating neurotransmitter function, as well as brain plasticity in neuronal networks. Moreover, closely-related AD proteins, including the amyloid-beta precursor protein, the estrogen receptor 1, acetylcholinesterase, and nitric oxide synthase 2, were selected as the bottleneck nodes of network for further verification by molecular docking. Our analytical results demonstrated that terpene, as the main compound of A. oxyphylla extract, exerts neuroprotective effects, providing new insights into the development of a natural therapy for the prevention and treatment of AD.