Dendrobium officinalis Flower Improves Learning and Reduces Memory Impairment by Mediating Antioxidant Effect and Balancing the Release of Neurotransmitters in Senescent Rats

Herbal medicines in Alzheimer's disease and the involvement of gut microbiota

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by memory loss and cognitive impairment. It severely affects the quality of life of victims. The prevalence of AD has been increasing in recent years. Therefore, it is of great importance to elucidate the pathogenic mechanism of AD and search for effective therapeutic approaches. Gut microbiota dysbiosis, an altered state of gut microbiota, has been well known for its involvement in the pathogenesis of AD. Much effort has been made in searching for approaches capable of modulating the composition of gut microbiota in recent years. Herbal medicines have attracted extensive attention in recent decades for the prevention and treatment of AD. Here, we gave an overview of the recent research progress on the modulatory effects of herbal medicines and herbal formulae on gut microbiota as well as the possible beneficial effects on AD, which may provide new insights into the discovery of anti-AD agents and their therapeutic potential for AD through modulating the composition of gut microbiota.

Anti-cyclooxygenase, anti-glycation, and anti-skin aging effect of Dendrobium officinale flowers’ aqueous extract and its phytochemical validation in aging

Introduction

Dendrobium officinale Kimura et Migo (D. officinale) , widely called as “life-saving immortal grass” by Chinese folk, is a scarce and endangered species. The edible stems of D. officinale have been extensively studied for active chemical components and various bioactivities. However, few studies have reported the well-being beneficial effects of D. officinale flowers (DOF). Therefore, the present study aimed to investigate the in vitro biological potency of its aqueous extract and screen its active components.

Methods

Antioxidant tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), the ferric reducing ability of plasma (FRAP), and intracellular reactive oxygen species (ROS) level analyses in primary human epidermal keratinocytes, anti-cyclooxygenase2 (COX-2) assay, anti-glycation assay (both fluorescent AGEs formation in a BSA fructose/glucose system and glycation cell assay), and anti-aging assay (quantification of collagen types I and III, and SA-β-gal staining assay) were conducted to determine the potential biological effects of DOF extracts and its major compounds. Ultra-performance liquid chromatography-electrospray ionisation-quadrupole-time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS/MS) was performed to investigate the composition of DOF extracts. Online antioxidant post-column bioassay tests were applied to rapidly screen major antioxidants in DOF extracts.

Results and discussion

The aqueous extract of D. officinale flowers was found to have potential antioxidant capacity, anti-cyclooxygenase2 (COX-2) effect, anti-glycation potency, and anti-aging effects. A total of 34 compounds were identified using UPLC-ESI-QTOF-MS/MS. Online ABTS radical analysis demonstrated that 1-O-caffeoyl-β-D-glucoside, vicenin-2, luteolin-6-C-β-D-xyloside-8-C-β--D-glucoside, quercetin-3-O-sophoroside, rutin, isoquercitrin, and quercetin 3-O-(6″-O-malonyl)-β-D-glucoside are the major potential antioxidants. In addition, all selected 16 compounds exerted significant ABTS radical scavenging ability and effective AGE suppressive activities. However, only certain compounds, such as rutin and isoquercitrin, displayed selective and significant antioxidant abilities, as shown by DPPH and FRAP, as well as potent COX-2 inhibitory capacity, whereas the remaining compounds displayed relatively weak or no effects. This indicates that specific components contributed to different functionalities. Our findings justified that DOF and its active compound targeted related enzymes and highlighted their potential application in anti-aging.

Quantitative Identification of Antioxidant Basis for Dendrobium Nobile Flower by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Dendrobium nobile is a beautiful orchid and a widely used medicinal plant. In vitro antioxidant assays suggested that D. noblie flower extracts showed significantly higher 2, 2′-azinobis-3-ethylbenzthiazoline-6-sulfonate (ABTS) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rates and much more ferric-reducing power than those of root, stem, leaf and fruit. To better understand the antioxidant basis of D. nobile flower, high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used for metabolic identification and quantification. Finally, there were 72 metabolites among the total of 712 identified components showed significant association (coefficient >0.8, p < 0.05) with ABTS scavenging rates, DPPH scavenging rates, and ferric-reducing power. The three enriched classes of flower metabolites, including amino acids and their derivatives, organic acids and their derivatives, and flavonoids, formed the main antioxidant basis. The significantly accumulated rutin, astragalin, isomucronulatol-7-O-glucoside, quercetin 4′-O-glucoside, methylquercetin O-hexoside, caffeic acid, caffeic acid O-glucoside, and p-coumaric acid (Log₂(fold change) >2, p < 0.01, distribution in flower >0.1%) made a key contribution to the higher antioxidant activities in flower. The relative quantification results of HPLC-MS/MS were verified by the common quantification methods. The antioxidant basis revealed of D. nobile flower will be helpful in the production of healthy or beauty products.

Phytochemical profiles of edible flowers of medicinal plants of Dendrobium officinale and Dendrobium devonianum

The discovery of new edible flowers that are nontoxic, innocuous flowers having human health benefits, surveys of their phytochemicals and utilization are of great scientific and commercial interest. Dendrobium officinale and Dendrobium devonianum are precious Traditional Chinese Medicine. During the massive commercial cultivation, a lot of flowers were produced and certified as edible flowers, and the phytochemical profiles and bioactivities warrant evaluate. The present study aimed to investigate the phytochemicals and antioxidative activities in flowers of D. officinale (DOF) and D. devonianum (DDF). In total, 474 metabolites were identified using a widely targeted metabonomics method, 16 amino acids and 6 flavonoids were measured using high-performance liquid chromatography (HPLC), and 8 fatty acids were detected using gas chromatography-mass spectrometry (GC-MS). Both flowers contained various amino acids, including 7 essential amino acids, diverse flavonoids, especially quercetin, kaempferol and their derivatives, and high levels of methyl linoleate and methyl linolenate. The relative levels of quercetin, kaempferol and their glycosides were higher in DDF than in DOF, whereas the relative levels of several flavonoids C-glycosides were high in DOF. Ethanol extracts of both DOF and DDF showed antioxidative capacities including the scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals. Both edible flowers contained flavonoids, amino acids, and fatty acids and have antioxidative activities, which should be explored for use in functional foods and pharmaceuticals.

Anti-inflammatory effect of Ganluyin, a Chinese classic prescription, in chronic pharyngitis rat model

Background

Ganluyin (GLY) is a famous classical prescription with a long history of use as a treatment for inflammatory conditions such as chronic pharyngitis (CP) in many parts of China. However, it has not been developed as a modern pharmaceutic and its anti-inflammatory mechanisms remain unclear. The aim of this study was to assess the anti-inflammatory efficacy of GLY and potential mechanisms in a rat model of CP.

Methods

The chemical profile of GLY was analyzed by HPLC-UV. We used a mouse model of ear edema and a rat model of paw edema. Specifically, xylene was used to induce edema on the surface of one ear in mice, and carrageenan was injected subcutaneously into the right hind paws of rats to induce paw edema. The paw thickness, ear weight, and ear perfusion were measured and recorded. The CP model in rats was induced by irritating the throat with 5% ammonia and was used to evaluate the therapeutic efficacy of GLY. Levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor (TNF-α), and prostaglandin E2 (PGE2) were measured by ELISA in serum, and protein expression of cyclooxygenase-2 (COX-2) and nuclear factor kappa-B p65 (NF-κB p65) in the throat were detected by immunohistochemistry and Western blot to evaluate the anti-inflammatory mechanism of GLY. Hematological assays were also conducted.

Results

There were four flavonoids identified in GLY: naringin, neohesperidin, baicalin, and wogonoside. The oral administration of GLY showed a significant inhibitory effect on xylene-induced ear swelling and ear blood flow in mice and significantly ameliorated rat right hind paw edema at doses of 6.2 and 12.4 g/kg. Mechanistic studies found that the anti-inflammatory activity of GLY was related to the inhibition of pro-inflammatory cytokines such as IL-1β, IL-6, TNF-α, and PGE2 and that GLY reduced the expression of COX-2 and NF-κB p65 proteins in the throat, attenuated throat injury, and reduced inflammatory exudates. Hematological analysis showed that treatment with GLY prevented increases in white blood cell (WBC), neutrophil (NEUT), lymphocyte (LYMPH) and monocyte (MONO) levels.

Conclusions

These studies indicated that GLY has beneficial anti-inflammatory effects on CP and that it acts through reducing pro-inflammatory factors such as IL-1β, IL-6, TNF-α, and PGE2, as well as decreasing WBC, NEUT, LYMPH and MONO levels and decreasing the expression of COX-2 and NF-κB p65 proteins. These findings may lay the groundwork for further studies of GLY as a suitable candidate for the treatment of inflammatory diseases such as CP.