Neuroprotective Assessment of Moringa oleifera Leaves Extract against Oxidative-Stress-Induced Cytotoxicity in SHSY5Y Neuroblastoma Cells

The current trend worldwide is searching plant extracts towards prevention of neurodegenerative disorders. This study aimed to investigate the neuroprotective effect of Alpinia galanga leaves (ALE), Alpinia galanga rhizomes (ARE), Vitis vinifera seeds (VSE), Moringa oleifera leaves (MLE), Panax ginseng leaves (PLE) and Panax ginseng rhizomes (PRE) ethanolic extracts on human neuroblastoma (SHSY5Y) cells. The 1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging of VSE and MLE were 81% and 58%, respectively. Ferric-reducing antioxidant power (FRAP) of ALE and MLE (33.57 ± 0.20 and 26.76 ± 0.30 μmol Fe(ΙΙ)/g dry wt., respectively) were higher than for the other extracts. Liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) revealed MLE active compounds. Intracellular study by nitro-blue tetrazolium (NBT) test showed that MLE and VSE had high O₂⁻ scavenging (0.83 ± 0.09 vs. 0.98 ± 0.08 mg/mL, respectively). MLE had the highest ROS scavenging followed by PRE (0.71 ± 0.08 vs. 0.83 ± 0.08 mg/mL, respectively), by 2,7-dichlorodihydrofluorescein diacetate (DCFHDA) assay. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity and neuroprotection tests on SHSY5Y showed that PRE had a better neuroprotective effect but higher cytotoxicity compared to MLE (viable cells 51% vs. 44%, IC₅₀ 1.92 ± 0.04 vs. 2.7 ± 0.2 mg/mL, respectively). In conclusion, among the studied plants, MLE has potential for developing as a neuroprotective agent.

Differential localization of flavonoid glucosides in an aquatic plant implicates different functions under abiotic stress

Flavonoids may mediate UV protection in plants either by screening of harmful radiation or by minimizing the resulting oxidative stress. To help distinguish between these alternatives, more precise knowledge of flavonoid distribution is needed. We used confocal laser scanning microscopy (cLSM) with the "emission fingerprinting" feature to study the cellular and subcellular distribution of flavonoid glucosides in the giant duckweed (Spirodela polyrhiza), and investigated the fitness effects of these compounds under natural UV radiation and copper sulphate addition (oxidative stress) using common garden experiments indoors and outdoors. cLSM "emission fingerprinting" allowed us to individually visualize the major dihydroxylated B-ring-substituted flavonoids, luteolin 7-O-glucoside and luteolin 8-C-glucoside, in cross-sections of the photosynthetic organs. While luteolin 8-C-glucoside accumulated mostly in the vacuoles and chloroplasts of mesophyll cells, luteolin 7-O-glucoside was predominantly found in the vacuoles of epidermal cells. In congruence with its cellular distribution, the mesophyll-associated luteolin 8-C-glucoside increased plant fitness under copper sulphate addition but not under natural UV light treatment, whereas the epidermis-associated luteolin 7-O-glucoside tended to increase fitness under both stresses across chemically diverse genotypes. Taken together, we demonstrate that individual flavonoid glucosides have distinct cellular and subcellular locations and promote duckweed fitness under different abiotic stresses.

Linarin and its aglycone acacetin abrogate actin ring formation and focal contact to bone matrix of bone-resorbing osteoclasts through inhibition of αvβ3 integrin and core-linked CD44

BACKGROUND

Since enhanced bone resorption due to osteoclast differentiation and activation cause skeletal diseases, there is a growing need in therapeutics for combating bone-resorbing osteoclasts. Botanical antioxidants are being increasingly investigated for their health-promoting effects on bone. Edible Cirsium setidens contains various polyphenols of linarin, pectolinarin, and apigenin with antioxidant and hepatoprotective effects.

PURPOSE

This study aimed to determine whether linarin present in Cirsium setidens water extracts (CSE) and its aglycone acacetin inhibited osteoclastogenesis of RANKL-exposed RAW 264.7 murine macrophages for 5 days.

METHODS

This study assessed the osteoprotective effects of CSE, linarin and acacetin on RANKL-induced differentiation and activation of osteoclasts by using MTT assay, TRAP staining, Western blot analysis, bone resorption assay actin ring staining, adhesion assay and immunocytochemical assay. This study explored the underlying mechanisms of their osteoprotection, and identified major components present in CSE by HPLC analysis.

RESULTS

Linarin and pectolinarin were identified as major components of CSE. Nontoxic linarin and acacetin as well as CSE, but not pectolinarin attenuated the RANKL-induced macrophage differentiation into multinucleated osteoclasts, and curtailed osteoclastic bone resorption through reducing lacunar acidification and bone matrix degradation in the osteoclast-bone interface. Linarin and acacetin in CSE reduced the transmigration and focal contact of osteoclasts to bone matrix-mimicking RGD peptide. Such reduction was accomplished by inhibiting the induction of integrins, integrin-associated proteins of paxillin and gelsolin, cdc42 and CD44 involved in the formation of actin rings. The inhibition of integrin-mediated actin ring formation by linarin and acacetin entailed the disruption of TRAF6-c-Src-PI3K signaling of bone-resorbing osteoclasts. The functional inhibition of c-Src was involved in the loss of F-actin-enriched podosome core protein cortactin-mediated actin assembly due to linarin and acacetin.

CONCLUSION

These observations demonstrate that CSE, linarin and acacetin were effective in retarding osteoclast function of focal adhesion to bone matrix and active bone resorption via inhibition of diffuse cloud-associated αvβ3 integrin and core-linked CD44.

Metabolic Alterations in Two Cirsium Species Identified at Distinct Phenological Stages using UPLC-QTOF/MS

INTRODUCTION

Cirsium chanroenicum and C. setidens are commonly used both in traditional folk medicine and as a food source. The quality of different species of Cirsium at different harvest times is a function of their metabolite composition, which is determined by the phenological stage.

OBJECTIVE

We sought to determine the differences in the metabolite composition of two species of Cirsium during different phenological stages using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight (QTOF) mass spectrometry (MS).

METHODOLOGY

Cirsium chanroenicum and C. setidens plants were collected at the floral budding and full flowering stages. Metabolic profiles of Cirsium extracts were determined using UPLC-QTOF/MS to characterise the differences between phenological stages, and the major metabolites were quantified using UPLC-QTOF/MS-multiple reaction monitoring (MRM).

RESULTS

At the full flowering stage, the levels of phenolic acids as well as components of the phenylpropanoid pathway were increased. Flavonoids predominated at the full flowering stage in both species. The levels of coumaric acid, kaempferol, and pectolinarigenin differed between the two species of Cirsium. Overall, these results suggest that components of the phenylpropanoid metabolic pathway are upregulated in the full flowering stage in Cirsium, although we did observe some variation between the species.

CONCLUSION

These results will help elucidate the metabolic pathways related to the different phases of the vegetative cycle, and may help determine the optimal season for the harvest of Cirsium with the highest levels of bioactive compounds. Copyright © 2017 John Wiley & Sons, Ltd.