Neuroprotective effects of Magnoliae Flos extract in mouse hippocampal neuronal cells.

Magnoliae Flos (MF) is a traditional medicinal herb used for managing rhinitis, sinusitis and headache. The purpose of the present study was to determine the neuroprotective effect of MF against glutamate-induced oxidative stress and to assess the underlying mechanism. Glutamate is a major endogenous excitatory neurotransmitter in the brain and contributes to the development of neurodegenerative diseases by excessive activation. MF extract was subjected to a neuroprotective effect assay in HT22 mouse hippocampal cells. The mechanism underlying the neuroprotective effect of MF extract was evaluated by assaying reactive oxygen species (ROS) levels, intracellular Ca2+ levels, mitochondrial membrane potential, glutathione level and antioxidant enzyme activity in HT22 cells. MF extract significantly decreased glutamate-induced death of HT22 cells (80.83 ± 7.34% relative neuroprotection). MF extract reduced the intracellular ROS and Ca2+ levels and increased the glutathione level and glutathione reductase and glutathione peroxide activities. Moreover, MF extract attenuated the mitochondrial membrane potential in HT22 cells. These results suggested that MF extract exerts a neuroprotective effect against oxidative stress HT22 cells, which was mediated by its antioxidant activity.

Simultaneous Determination of Four Compounds, Campesterol, Emodin8-O-ß-D-Glucopyranoside, Quercetin, and Isoquercitrin in Reynoutria sachalinensis by High-performance Liquid Chromatography-Diode Array Detector.

BACKGROUND: Reynoutria sachalinensis is a well-known and used herbal medicine to treatment of arthralgia, jaundice, amenorrhea, coughs, carbuncles, and sores. OBJECTIVE: We have developed high-performance liquid chromatography analysis method for simultaneous determination of isolated four compounds, campesterol, emodin8-O-ß-D-glucopyranoside, quercetin, and isoquercitrin from R. sachalinensis is. MATERIALS AND METHODS: The four compounds were separated on Shiseido C18 column (S-5 µm, 4.6 mm I.D. ×250 mm) at a column temperature of 25°C. The mobile phase composed of water and methanol with gradient elution system, and flow rate is 1.0 ml/min. The detection wavelength was set at 205 nm. RESULTS: Validation of this analytical method was evaluated by linearity, precision, and accuracy test. This established method had good linearity (R2 > 0.997). The relative standard deviation values of intra- and inter-day testing were indicated that <2%, and accuracy is 91.66%-103.31% at intraday and 91.69%-103.31% at intraday. The results of recovery test were 92.60%-108.99%. CONCLUSION: In these results, developed method was accurate and reliable to the quality evaluation of campesterol, emodin 8-O-ß-D-glucopyranoside, quercetin, and isoquercitrin isolated from R. sachalinensis. SUMMARY: We have developed high-performance liquid analysis method for simultaneous determination of 4 compounds of Reynoutria sachalinensis. Abbreviations used: HPLC: High-performance liquid chromatography, DAD: Diode array detector, LOD: Limit of detection, LOQ: Limit of quantitation, ICH: International Conference on Harmonisation.

Neuroprotective compounds from Reynoutria sachalinensis.

Glutamate is a neurotransmitter in central nervous system. Overexpression of glutamate leads to oxidative stress, resulting in several neurodegenerative disorders that include Alzheimer's disease. The n-hexane fraction of stems and ethyl acetate (EtOAc) fraction of flowers of Reynoutria sachalinensis provide neuroprotection against glutamate-induced oxidative toxicity in HT22 cells. In this study, 1-decanol (1), ß-amyrin (2), dammaran-3ß-ol (3), campesterol (4), daucosterol (5), ergosterol peroxide (6), emodin 8-O-ß-D-glucopyranoside (7), quercetin (8) and isoquercitrin (9) were isolated from n-hexane fractions of stems and EtOAc fractions of flowers of R. sachalinensis. Their neuroprotective activity was evaluated by MTT assay. 1-Decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin exhibited neuroprotective activity. These compounds decreased reactive oxygen species level, showed anti-oxidant activity with DPPH radical and in a H2O2 scavenging assay. Therefore, the neuroprotective activity of 1-decanol, campesterol, ergosterol peroxide, quercetin and isoquercitrin are associated with antioxidant activity.

Neuroprotective effect of Aronia melanocarpa extract against glutamate-induced oxidative stress in HT22 cells.

BACKGROUND: Glutamate (an endogenous excitatory neurotransmitter) at high concentrations contributes to the development of neurodegenerative diseases. Aronia melanocarpa (A. melanocarpa) berries contain anthocyanins and have high antioxidant activities. In this study, we evaluated whether A. melanocarpa berries could protect neuronal cells against glutamate-induced oxidative stress. METHOD: A. melanocarpa berries exerted a protective effect against cytotoxicity in HT22 mouse hippocampal cells by MTT assay. We evaluated oxidative stress parameters including ROS level, intracellular Ca2+ level, glutathione level and antioxidant enzyme activity in HT22 cells to elucidate the mechanism of its neuroprotective effect. RESULTS: A. melanocarpa berries decreased glutamate-induced death of HT22 cells. In addition, A. melanocarpa berries reduced ROS and intracellular Ca2+ levels. Glutathione level, antioxidant enzymes, glutathione reductase and glutathione peroxide activities and mitochondrial membrane potential were also increased in HT22 cells. CONCLUSION: These results suggested that A. melanocarpa berries protected HT22 cells by exerting an antioxidant effect.