20(S)-protopanaxadiol, an active ginseng metabolite, exhibits strong antidepressant-like effects in animal tests

A Review of Antidepressant Effects and Mechanisms of Three Common Herbal Medicines: Panax ginseng, Bupleurum chinense, and Gastrodia elata

OBJECTIVES

Major depressive disorder (MDD) has been reported to affect an increasing number of individuals due to the modern lifestyle. Because of its complicated mechanisms and recurrent attacks, MDD is considered a refractory chronic disease. Although the mainstream therapy for MDD is chemical drugs, they are not a panacea for MDD because of their expensiveness, associated serious adverse reactions, and endless treatment courses. Hence, we studied three kinds of herbal medicines, namely, Panax ginseng C. A. Mey (PGM), Bupleurum chinense DC (BCD), and Gastrodia elata Blume (GEB), and reviewed the mechanisms underlying their antidepressant properties to provide a reference for the development of antidepressants and clinical medications.

METHODS

An extensive range of medicinal, clinical, and chemistry databases and search engines were used for our literature search. We searched the literature using certain web literature search engines, including Google Scholar, PubMed, Science Direct, CNKI (China National Knowledge Infrastructure), and Web of Science.

RESULTS

Experimental research found that active compounds of these three medicines exhibited good antidepressant effects in vivo and in vitro. Clinical investigations revealed that single or combined treatment of these medicines improved certain depressive symptoms. Antidepressant mechanisms are summarized based on this research.

CONCLUSION

The antidepressant mechanism of these three medicines includes but is not limited to ameliorating inflammation within the brain, reversing the hypothalamic-pituitary adrenal axis (HPA) system hyperfunction, inhibiting monoamine neurotransmitters reuptake, anti-neuron apoptosis and preventing neurotoxicity, and regulating depressive-related pathways such as the BDNF pathway and the PI3K/Akt/mTOR pathway.

Mechanistic insights into the role of plant polyphenols and their nano-formulations in the management of depression

Depression is a condition characterized by low mood and an aversion to activity, that causes behavioral problems, poor quality of life and limits daily life activities. It is considered as the fourth leading cause of disability worldwide. Selective Serotonin Reuptake Inhibitors (SSRIs) Monoamine Oxidase (MAO) inhibitors, Tricyclic Antidepressants (TCAs), and atypical antidepressants are some of the conventional medications used to treat depression. However, only about half of patients with major depressive disorder (MDD) respond effectively to first-line antidepressant therapy. Additionally, there are a number of drawbacks to standard antidepressants, such as anti-cholinergic side effects, drug-drug interactions, and food-drug interactions, which prompts researchers to look at alternative approaches to the treatment of depression. Medicinal plants and their metabolites are extensively tested for their efficacy against depression. Electronic databases such as Google scholar, Science Direct, SciFinder and PubMed were used to search relevant literature on the role of polyphenols in depression. Plants-derived Polyphenols represent a major class of compounds extensively distributed in plants. Number of polyphenols have demonstrated antidepressant activity, among which berberine, piperine, curcumin, naringenin, ascorbic acid and ginsenosides are extensively evaluated. The medicinal plants and their derived compounds mediated synthesized green nanoparticles have also exhibited considerable efficacy in the management of depression. The therapeutic effects of these phytochemicals is mediated via differentiation and inhibition of neuronal cell apoptosis, promotion of neuronal cell survival and modulation of key neurotransmitters. The aim of this study is to review compressively the chemical, pharmacological and neurological evidence showing the potential of polyphenols in depression.

Antidepressant Active Ingredients From Chinese Traditional Herb Panax Notoginseng: A Pharmacological Mechanism Review

Depression is one of the most common mental illnesses in the world and is highly disabling, lethal, and seriously endangers social stability. The side effects of clinical drugs used to treat depression are obvious, and the onset time is longer. Therefore, there is a great demand for antidepressant drugs with better curative effects, fewer side effects, and shorter onset time. Panax notoginseng, a Chinese herbal medication, has been used to treat depression for thousands of years and shown to have a therapeutic effect on depression. This review surveyed PubMed’s most recent 20 years of research on Panax notoginseng’s use for treating depression. We mainly highlight animal model research and outlined the pathways influenced by medicines. We provide a narrative review of recent empirical evidence of the anti-depressive effects of Panax Notoginseng and novel ideas for developing innovative clinical antidepressants with fewer side effects.

Dietary Supplementation With Yucca Alleviates Heat Stress in Growing Broilers Exposed to High Ambient Temperature

Yucca contains high a content of saponin that has a glucocorticord-like effect in animals, e.g., anti-inflammation and anti-microbiota. The objective of the present study was to test the hypothesis that dietary supplementation of yucca powder may alleviate heat stress and improve growth performance of growing broilers subjected to cycling high ambient temperature. A total of 240 male broiler chicks (yellow feathered chicken) aged 28 days, with body weight (BW) of 792 ± 43.7 g, were randomly allocated to one of four treatments (6 replicates per treatment): control (normal temperature, 24 ± 2°C, 24 h), fed diets supplemented with 100 mg/kg yucca under normal temperature (Y), high ambient temperature exposure (HT, 34 ± 2°C, 11 h), fed diets supplemented with 100 mg/kg yucca (HT+Y) under high ambient temperature. After 7 days of adaption, the experiment was conducted for 4 weeks (aged 28–56 days). HT significantly reduced feed intake, BW, and average daily gain (ADG) of broiler, but yucca improved the feed intake under HT condition. Yucca supplementation reduced (P < 0.05) the HT-induced increase in temperature of rectum and leg skin. Supplementation of yucca increased the hypothalamic mRNA expression of TRPV2, TRPV4, and TRPM8 (P < 0.05). Yucca reduced (P < 0.05) the plasma lipid oxidation product malondialdehyde (MDA), but did not affect the activities of antioxidant enzyme superoxide oxidase (SOD) and glutathione peroxidase (Gpx). Yucca did not affect the plasma neuro peptide Y (NPY), which was reduced by HT, yucca reduced circulation cholecystokinin (CCK) and hypothalamic mRNA expression of CCK. Supplementation of yucca increased the mRNA expression of both heat and cool sensing receptors. The results of the present study indicate that yucca could improve antioxidant status and attenuate the heat stress response by regulating hypothalamic temperature-sensing genes in growing chickens. Besides, yucca supplementation improved feed intake probably through modulating CCK in growing broilers under high ambient temperature.

Anti-Depressant Properties of Crocin Molecules in Saffron

Saffron is a valued herb, obtained from the stigmas of the C. sativus Linn (Iridaceae), with therapeutic effects. It has been described in pharmacopoeias to be variously acting, including as an anti-depressant, anti-carcinogen, and stimulant agent. The therapeutic effects of saffron are harbored in its bioactive molecules, notably crocins, the subject of this paper. Crocins have been demonstrated to act as a monoamine oxidase type A and B inhibitor. Furthermore, saffron petal extracts have experimentally been shown to impact contractile response in electrical field stimulation. Other research suggests that saffron also inhibits the reuptake of monoamines, exhibits N-methyl-d-aspartate antagonism, and improves brain-derived neurotrophic factor signaling. A host of experimental studies found saffron/crocin to be similarly effective as fluoxetine and imipramine in the treatment of depression disorders. Saffron and crocins propose a natural solution to combat depressive disorders. However, some hurdles, such as stability and delivery, need to be overcome.

Simultaneous Quantification of Four Ginsenosides in Rat Plasma and Its Application to a Comparative Pharmacokinetic Study in Normal and Depression Rats Using UHPLC-MS/MS

A sensitive method has been developed for simultaneous determination of ginsenoside Rh₁ (G-Rh₁), ginsenoside Rb₁ (G-Rb₁), ginsenoside Rc (G-Rc), and ginsenoside Rd (G-Rd) in rat plasma of normal and depression model group after oral administration of their solutions by using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-QQQ-MS). The biological samples were prepared by protein precipitation. Ginsenoside Rg₃ (G-Rg₃) was used as an internal standard (IS). MS analysis was performed under the multiple reaction monitoring (MRM) with electron spray ionization (ESI) operated in the negative mode. The method showed good linearity over a wide concentration range (R ² > 0.999) and obtained lower limits of quantification (LLOQ) of 5 ng/mL. The whole analysis procedure could be completed in as short as 16.5 min. The intraday precisions, interday precisions, and stabilities were less than 10%. The extraction recoveries from rat plasma were exceeded 86.0%. The results indicated that there were significant differences between the two groups on pharmacokinetics parameters; the absorptions of four analytes in the depression group were higher than those in the normal group because the liver metabolism and internal environment of the model rats had been affected.

Protopanaxadiol alleviates neuropathic pain by spinal microglial dynorphin A expression following glucocorticoid receptor activation

BACKGROUND AND PURPOSE

New remedies are required for the treatment of neuropathic pain due to insufficient efficacy of available therapies. This study provides a novel approach to develop painkillers for chronic pain treatment.

EXPERIMENTAL APPROACH

The rat formalin pain test and spinal nerve ligation model of neuropathic pain were used to evaluate antinociception of protopanaxadiol. Primary cell cultures, immunofluorescence staining, and gene and protein expression were also performed for mechanism studies.

KEY RESULTS

Gavage protopanaxadiol remarkably produces pain antihypersensitive effects in neuropathic pain, bone cancer pain and inflammatory pain, with efficacy comparable with gabapentin. Long-term PPD administration does not induce antihypersensitive tolerance, but prevents and reverses the development and expression of morphine analgesic tolerance. Oral protopanaxadiol specifically stimulates spinal expression of dynorphin A in microglia but not in astrocytes or neurons. Protopanaxadiol gavage-related pain antihypersensitivity is abolished by the intrathecal pretreatment with the microglial metabolic inhibitor minocycline, dynorphin antiserum or specific κ-opioid receptor antagonist GNTI. Intrathecal pretreatment with glucocorticoid receptor)antagonists RU486 and dexamethasone-21-mesylate, but not GPR-30 antagonist G15 or mineralocorticoid receptor antagonist eplerenone, completely attenuates protopanaxadiol-induced spinal dynorphin A expression and pain antihypersensitivity in neuropathic pain. Treatment with protopanaxadiol, the glucocorticoid receptor agonist dexamethasone and membrane-impermeable glucocorticoid receptor agonist dexamethasone-BSA in cultured microglia induces remarkable dynorphin A expression, which is totally blocked by pretreatment with dexamthasone-21-mesylate.

CONCLUSION AND IMPLICATIONS

All the results, for the first time, indicate that protopanaxadiol produces pain antihypersensitivity in neuropathic pain probably through spinal microglial dynorphin A expression after glucocorticoid receptor activation and hypothesize that microglial membrane glucocorticoid receptor/dynorphin A pathway is a potential target to discover and develop novel painkillers in chronic pain.

The effect of ginsenosides on depression in preclinical studies: A systematic review and meta-analysis

BACKGROUND

Many ginsenosides have been shown to be efficacious for major depressive disorder (MDD), which is a highly recurrent disorder, through several preclinical studies. We aimed to review the literature assessing the antidepressant effects of ginsenosides on MDD animal models, to establish systematic scientific evidence in a rigorous manner.

METHODS

We performed a systematic review on the antidepressant effects of ginsenoside evaluated in in vivo studies. We searched for preclinical trials from inception to July 2019 in electronic databases such as Pubmed and Embase. In vivo studies examining the effect of a single ginsenoside on animal models of primary depression were included. Items of each study were evaluated by two independent reviewers. A meta-analysis was conducted to assess behavioral changes induced by ginsenoside Rg1, which was the most studied ginsenoside. Data were pooled using the random-effects models.

RESULTS

A total of 517 studies were identified, and 23 studies were included in the final analysis. They reported on many ginsenosides with different antidepressant effects and biological mechanisms of action. Of the 12 included articles assessing ginsenoside Rg1, pooled results of forced swimming test from 9 articles (mean difference (MD): 20.50, 95% CI: 16.13-24.87), and sucrose preference test from 11 articles (MD: 28.29, 95% CI: 22.90-33.69) showed significant differences compared with vehicle treatment. The risk of bias of each study was moderate, but there was significant heterogeneity across studies.

CONCLUSION

These estimates suggest that ginsenosides, including ginsenoside Rg1, reduces symptoms of depression, modulates underlying mechanisms, and can be a promising antidepressant.

Platelet Protease Activated Receptor 1 Is Involved in the Hemostatic Effect of 20(S)-Protopanaxadiol by Regulating Calcium Signaling

Panax notoginseng (Burk.) F.H. Chen has long been used to stop bleeding for hundreds of years in China. At present, only dencichine, notoginsenoside Ft1, and 20(S)-protopanaxadiol (PPD) showed hemostatic effect. However, the molecular mechanism of PPD on the platelet aggragetion needs to be further investigated. The study aims to evaluate the hemostatic effect of PPD and reveal its interacting targets using a series of experiments. In this study, the bleeding time was measured in mouse tail amputation and liver scratch models to evaluate hemostatic effect of PPD. The routine blood and plasma coagulation parameters in NS, HC, and PPD (2, 4, and 8 mg/kg) groups were measured using a blood analyzer. Platelet aggregation rate and ATP release were analyzed by a platelet aggregometer. Subsequently, the degranulation marker CD62P and PAC-1, and the concentrations of cytosolic Ca²⁺ ([Ca²⁺]_i), cAMP, cGMP, and PAC-1 expressions were also assessed. We found that PPD shorted the bleeding time on the mouse tail amputation and liver scratch models and mainly increased blood platelet count in the rats after subcutaneous injection for 4 h. Meanwhile, PPD decreased APTT, increased FIB content, and directly induced platelet aggregation in vitro. In the absence of Ca²⁺, PPD induced the increase of [Ca²⁺]_i and slightly increased the levels of CD62P and PAC-1. After the addition of 1 mM Ca²⁺, PPD treatment markedly promoted platelet activation by promoting ATP level, releasing CD62P and increasing PAC-1 binding in washed platelets. Excitingly, PPD-induced changes including platelet aggregation, decreased cAMP content, and the increases of CD62P and PAC-1 were significantly reversed by protease-activated receptor 1 (PAR-1) antagonist, vorapaxar, which showed similar function as thrombin. In addition, molecular docking analysis and ELISA assay demonstrated that PPD had a promising docking score with -6.6 kcal/mol and increased PAR-1 expression in human platelets, which indicated that PAR-1 is involved in PPD-induced platelet aggregation by regulating calcium signaling. Collectively, our study could provide the new insights of PPD as an essential hemostatic ingredient in Panax notoginseng for the treatment of hemorrhagic disease.

Ginsenoside Rk1 alleviates LPS-induced depression-like behavior in mice by promoting BDNF and suppressing the neuroinflammatory response

Ginsenoside Rk1, a saponin component produced by heat-processed ginseng, possesses anti-inflammatory and antitumor activities. The aim of our study was to explore the effects of Rk1 on Lipopolysaccharide (LPS)-induced depression-like behavior in mice and to observe its effects on oxidative stress, the inflammatory response and brain-derived neurotrophic factor (BDNF) - tropomyosin-related kinase B (TrkB) signaling. After mice were pretreated with Rk1 (5, 10, and 20 mg/kg), the immobility time in both the forced swimming test (FST) and the tail suspension test (TST) was reduced, suggesting that Rk1 effectively improved depression-like symptoms. Rk1 (10 and 20 mg/kg) and Fluoxetine (Flu, 20 mg/kg) increased the activity of the antioxidant enzyme SOD in the brain and protected against lipid peroxidation. Different concentrations of Rk1 (10 and 20 mg/kg) and Flu significantly decreased the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1 in serum, while Rk1 (5, 10, and 20 mg/kg) and Flu reduced the concentrations of IL-6 in a dose-dependent manner. Western blot analysis showed that the administration of Rk1 (20 mg/kg) and Flu significantly downregulated the level of Sirt1 and that Rk1 (5, 10, and 20 mg/kg) and Flu inhibited the p-NF-κb/NF-κb and p-IκB-α/IκB-α ratios, which indicated that the neuroprotective effect of Rk1 may be related to the suppression of inflammation. In addition 5, 10 and 20 mg/kg Rk1 significantly attenuated the LPS-induced decreases in BDNF and TrkB. These results indicated that Rk1 acts as an antidepressant through its antioxidant activity, the inhibition of neuroinflammation, and the positive regulation of the BDNF-TrkB pathway. This study may help develop active ginsenoside-based compounds for neurodegenerative diseases.

Rapid action of mechanism investigation of Yixin Ningshen tablet in treating depression by combinatorial use of systems biology and bioinformatics tools

ETHNOPHARMACOLOGICAL RELEVANCE

Yixin Ningshen tablet is a CFDA-approved TCM formula for treating depression clinically. However, little is known about its active compounds and related potential target proteins, so far, no researches have been performed to investigate its mechanism of action for the treatment of depression.

AIM OF THE STUDY

Here we develop an original bioinformatics pipeline composed of text mining tools, database querying and systems biology combinatorial analysis, which is applied to rapidly explore the mechanism of action of Yixin Ningshen tablet in treating depression.

MATERIALS AND METHODS

Text mining and database query were applied to identify active compounds in Yixin Ningshen tablet for the treatment of depression. Then SwissTargetPrediction was used to predict their potential target proteins. PubMed was retrieved to summarize known depression related systems biology results. Ingenuity Pathway Analysis (IPA) tools and STRING were applied to construct a compound-target protein-gene protein-differential protein-differential metabolite network with the integration of compound-target interaction and systems biology results, as well as enrich the target proteins related pathways. ChEMBL and CDOCKER were used to validate the compound-target interactions.

RESULTS

62 active compounds and their 286 potential target proteins were identified in Yixin Ningshen tablet for the treatment of depression. The construction of compound-target protein-gene protein-differential protein-differential metabolite network shrinked the number of potential target proteins from 286 to 133. Pathway enrichment analysis of target proteins indicated that Neuroactive ligand-receptor interaction, Calcium signaling pathway, Serotonergic synapse, cAMP signaling pathway and Gap junction were the common primary pathways regulated by both Yixin Ningshen Tablet and anti-depressant drugs, and MAPK, Relaxin, AGE-RAGE, Estrogen, HIF-1, Jak-STAT signaling pathway, Endocrine resistance, Arachidonic acid metabolism and Regulation of actin cytoskeleton were the specifically main pathways regulated by Yixin Ningshen tablet for the treatment of depression. Further validations based on references and molecular docking results demonstrated that Yixin Ningshen tablet could primarily target MAPT, CHRM1 and DRD1, thus regulating serotonergic neurons, cholinergic transmission, norepinephrine and dopamine reuptake for the treatment of depression.

CONCLUSIONS

This study displays the power of extensive mining of public data and bioinformatical repositories to provide answers for a specific pharmacological question. It furthermore demonstrates how the usage of such a combinatorial approach is advantageous for the biologist in terms of experimentation time and costs.

Penicillium sp. YJM-2013 induces ginsenosides biosynthesis in Panax ginseng adventitious roots by inducing plant resistance responses

Objective

Fusarium oxysporum is a common pathogenic fungus in ginseng cultivation. Both pathogens and antagonistic fungi have been reported to induce plant resistance responses, thereby promoting the accumulation of secondary metabolites. The purpose of this experiment is to compare the advantages of one of the two fungi, in order to screen out more effective elicitors. The mechanism of fungal elicitor-induced plant resistance response is supplemented.

Methods

A gradient dilution and the dural culture were carried out to screen strains. The test strain was identified by morphology and 18 s rDNA. The effect of different concentrations (0, 50, 100, 200, 400 mg/L) of Penicillium sp. YJM-2013 and F. oxysporum on fresh weight and ginsenosides accumulation were tested. Signal molecules transduction, expression of transcription factors and functional genes were investigated to study the induction mechanism of fungal elicitors.

Results

Antagonistic fungi of F. oxysporum was identified as Penicillium sp. YJM-2013, which reduced root biomass. The total ginsenosides content of Panax ginseng adventitious roots reached the maximum (48.95 ± 0.97 mg/g) treated with Penicillium sp. YJM-2013 at 200 mg/L, higher than control by 2.59-fold, in which protopanoxadiol-type ginsenosides (PPD) were increased by 4.57 times. Moreover, Penicillium sp. YJM-2013 activated defense signaling molecules, up-regulated the expression of PgWRKY 1, 2, 3, 5, 7, 9 and functional genes in ginsenosides synthesis.

Conclusion

Compared with the pathogenic fungi F. oxysporum, antagonistic fungi Penicillium sp. YJM-2013 was more conducive to the accumulation of ginsenosides in P. ginseng adventitious roots. Penicillium sp. YJM-2013 promoted the accumulation of ginsenosides by intensifying the generation of signal molecules, activating the expression of transcription factors and functional genes.

Dammarane-type leads panaxadiol and protopanaxadiol for drug discovery: Biological activity and structural modification

Based on the definite therapeutic benefits, such as neuroprotective, cardioprotective, anticancer, anti-diabetic and so on, the Panax genus which contains many valuable plants, including ginseng (Panax ginseng C.A. Meyer), notoginseng (Panax notoginseng) and American ginseng (Panax quinquefolius L.), attracts research focus. Actually, the biological and pharmacological effects of the Panax genus are mainly attributed to the abundant ginsenosides. However, the low membrane permeability and the gastrointestinal tract influence seriously limit the absorption and bioavailability of ginsenosides. The acid or base hydrolysates of ginsenosides, 20 (R,S)-panaxadiol and 20 (R,S)-protopanaxadiol showed improved bioavailability and diverse pharmacological activities. Moreover, relative stable skeletons and active hydroxyl group at C-3 position and other reactive sites are suitable for structural modification to improve biological activities. In this review, the pharmacological activities of panaxadiol, protopanaxadiol and their structurally modified derivatives are comprehensively summarized.

Insights into gastrointestinal microbiota-generated ginsenoside metabolites and their bioactivities

The gastrointestinal microbiota and host co-evolve into a complex 'super-organism,' and this relationship plays a vital role in many physiological processes, such as drug metabolism. Ginseng is an important medicinal resource and the main ingredients are ginsenosides, which are less polar, difficult to absorb, and have low bioavailability. However, studies have shown that the biological activity of ginsenosides such as compound K (CK), ginsenoside Rg3 (Rg3), ginsenoside Rh2 (Rh2), 20(S)-protopanaxatriol (20(S)-PPT), and 20(S)-protopanaxadiol (20(S)-PPD) is closely related to the gastrointestinal microbiota. In this paper, the metabolic pathway of gastrointestinal microbiota-generated ginsenosides and the main pharmacological effects of these metabolites are discussed. Furthermore, our study provides a new insight into the discovery of novel drugs. Specifically, in new drug screening process, candidates with low biological activity and bioavailability should not be excluded. Because their metabolites may exhibit good pharmacological effects due to the involvement of the gastrointestinal microbiota. In addition, in further research studies to develop probiotics, a combination of agents could exert greater efficacy than single agents. Moreover, differences in lifestyle and diet lead to differences in the gastrointestinal microbiota in the human body. Therefore, administration of the same drug dose to different individuals could elicit different therapeutic effects, owing to the involvement of the gastrointestinal microbiota. Thus, treatment accuracy could be achieved by detecting the gastrointestinal microbiota before drug treatment.HighlightsGastrointestinal microbiota plays a decisive role in bioactivities of ginsenosides.The metabolic pathway and main pharmacological effects of ginsenoside metabolites are discussed.It provides new insights into novel drug discovery and further research to find probiotic, combinations to exert greater efficacy.Differences in lifestyle and diet, varies the gastrointestinal microbiota in the human body. However, the same dose of a drug producing different therapeutic effects may involve gastrointestinal microbiota.

How Ginsenosides Trigger Apoptosis in Human Lung Adenocarcinoma Cells

Panax ginseng is a natural medicine that has been used globally for a long time. Moreover, several studies have reported the effective activity of ginseng in treating malignancies. Various agents containing ginseng were widely used as an antitumor treatment nowadays. Lung cancer is the most common fatal cancer in China, and lung adenocarcinoma is the most common histological type of non-small cell lung cancer (NSCLC). What's worse, many patients may have a failed response to conventional therapy including chemotherapy, radiotherapy, or molecule-targeted therapy due to drug resistance. Apoptosis is a highly ordered cellular suicidal process that plays an essential role in maintaining normal homeostasis. The pharmacological mechanism of many antineoplastic drugs involves triggering of apoptotic process. In several recent studies, ginsenosides are regarded as major active components of ginseng that have the potential to control lung cancer. Most of these results have proved that ginsenosides induce apoptosis in lung cancer cells through many different signaling pathways such as PI3K/Akt, NF-κB, EGFR, and so on. This study is aimed at reviewing the signaling pathways that underlie ginsenosides-triggered apoptotic process and encourage further studies to target promising agents against lung cancer treatment.

Formulation And Evaluation Of Nanostructured Lipid Carriers (NLCs) Of 20(S)-Protopanaxadiol (PPD) By Box-Behnken Design

Background

20(S)-Protopanaxadiol (PPD) has a higher anti-wrinkle effect than the other glycone forms of ginsenosides. However, as PPD has low solubility in water and a high molecular weight, it cannot easily penetrate the stratum corneum layer, which is the rate-limiting step of topical skin delivery. Thus, the objective was to enhance the topical skin deposition of PPD using an optimized nanostructured lipid carriers (NLC) formulation. NLC formulations were optimized using a Box-Behnken design.

Materials and methods

NLC formulations were optimized using a Box-Behnken design, where the amount of PDD (X₁), volume of the liquid lipid (X₂), and amount of surfactant (X₃) were set as the independent variables, while the particle size (Y₁), polydispersity index (PDI) (Y₂), and entrapment efficiency (EE) (Y₃) were dependent factors. An in vitro deposition study was performed using Strat-M^® and human cadaver skin, while in vivo skin irritation effect of the NLC formulation was evaluated in humans.

Results

An NLC was successfully prepared based on the optimized formulation determined using the Box-Behnken design. The particle size, PDI, and EE of the NLC showed less than 5% difference from the predicted values. The in vitro deposition of PPD after the application of the NLC formulation on a Strat-M^® artificial membrane and human cadaver skin was significantly higher than that of the controls. Moreover, NLC formulations with and without PDD were not skin irritants in a human study.

Conclusion

An NLC formulation for the topical delivery of PPD was successfully optimized using the Box-Behnken design, and could be further developed to enhance the topical skin deposition of PPD.

Ginseng and heme oxygenase-1: The link between an old herb and a new protective system

Ginseng is an ancient herb, belonging to Asian traditional medicine, that has been considered as a restorative to enhance vitality for centuries. It has been demonstrated that the antioxidant action of ginseng may be mediated through activation of different cellular signaling pathways involving the heme oxygenase (HO) system. Several compounds derived from ginseng have been studied for their potential role in brain, heart and liver protection, and the Nrf2 pathway seems to be the most affected by these natural molecules to exert this effect. Ginseng is also popularly used in cancer patients therapy for the demonstrated capability to defend tissues from chemotherapy-induced damage. Reported results suggest that the effect of ginseng is primarily associated with ROS scavenging, mainly exerted through the activation of Nrf2 pathway, and the consequent induction of HO-1 levels. This review aims to discuss the connection between the antioxidant properties of ginseng and the activation of the HO system, as well as to outline novel therapeutic applications of this medicinal plant to human health.

Efficacy and safety of Chinese herbal medicine for depression: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To conduct a systematic review to assess the current evidence available for the effectiveness and safety of Chinese herbal medicine (CHM) for depression.

METHODS

An electronic search was conducted in eight databases from inception until April 2018. Randomized controlled trials with risk of bias (RoB) score ≥ 4 according to the Cochrane RoB tool were included for analyses. The primary outcome was the severity of depression. The secondary outcomes were total effective rate (TER) and adverse events. The minimally important difference (MID) of the severity of depression was a reduction in the Hamilton Rating Scale for Depression 17 items (HAMD-17) scores by 4. RevMan 5.3 Software was used for data analyses. GRADE system was used to assess the certainty of evidence.

RESULTS

A total of 40 eligible studies with 3549 subjects were identified. Meta-analyses showed that CHM monotherapy had better clinically effects than placebo according to HAMD-17 score (Mean Difference (MD) = -4.53, 95% CI (-5.69, -3.37), P < 0.00001; Certainty of evidence: Moderate) and TER (Risk Ratio (RR) = 2.15, 95% CI (1.61, 2.88), P < 0.00001, Certainty of evidence: Low). Meta-analyses showed that CHM was as effective as western conventional medications (WCM) in TER (RR = 0.99, 95% CI (0.95, 1.02), P = 0.41, Certainty of evidence: High) and in reducing HAMD-17 score (MD = 0.44, 95% CI (-0.11, 0.99), P = 0.12, Certainty of evidence: Moderate). Meta-analyses showed that CHM in combination with WCM was better than WCM in TER (RR = 1.16, 95% CI (1.07, 1.27), P = 0.0004, Certainty of evidence: High), while had comparable clinically effects with WCM according to HAMD-17 score (MD = -2.51, 95% CI (-3.24, -1.77), P < 0.00001, Certainty of evidence: Moderate). In additional, CHM were associated with less adverse events than WCM, and adding CHM to WCM reduced adverse events.

CONCLUSION

The findings of present systematic review, at least to a certain extent, provided supporting evidence for the routine use of CHM for depression.

Tentative identification of 20(S)-protopanaxadiol metabolites in human plasma and urine using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry

BACKGROUND

20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant.

METHODS

In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial.

RESULTS

A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments.

CONCLUSION

The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

Genetically modified rice produces ginsenoside aglycone (protopanaxadiol)

MAIN CONCLUSION

Protopanaxadiol is dammarane-type tetracyclic triterpene sapogenin found in ginseng and has a high medicinal values. We successfully constructed transgenic rice producing protopanaxadiol by introducing the ginseng PgDDS and CYP716A47 genes in this crop plant. Protopanaxadiol (PPD), an aglycone of ginsenosides, possesses pleiotropic anticarcinogenesis activities in many cancers. Here, we constructed transgenic rice overexpressing the Panax ginseng dammarenediol-II synthase gene (PgDDS) and protopanaxadiol synthase gene (CYP716A47) driven by a rice endosperm-specific α-globulin promoter. Among more than 50 independent lines, five transgenic lines were selected. The introduction of the genes in the T1 generation of the transgenic lines was confirmed by genomic PCR. The expression of the introduced genes in T2 seeds was confirmed by qPCR. Methanol extracts of transgenic rice grains were analyzed by LC/MS to detect the production of PPD and dammarenediol-II (DD). The production of both PPD and DD was identified not only by comparing the retention times but also mass fraction patterns of authentic PPD and DD standards. The mean concentrations of PPD and DD in rice grains were 16.4 and 4.5 µg/g dry weight, respectively. The invention of genetically engineered rice grains producing PPD and DD can be applied to rice breeding to reinforce new medicinal values.

Antidepressant effects of ginsenoside Rf on behavioral change in the glial degeneration model of depression by reversing glial loss

Background

Depression is a common neuropsychiatric disease that shows astrocyte pathology. Ginsenoside Rf (G-Rf) is a saponin found in Panax ginseng which has been used to treat neuropsychiatric diseases. We aimed to investigate antidepressant properties of G-Rf when introduced into the L-alpha-aminoadipic acid (L-AAA)–infused mice model which is representative of a major depressive disorder that features diminished astrocytes in the brain.

Methods

L-AAA was infused into the prefrontal cortex (PFC) of mice to induce decrease of astrocytes. Mice were orally administered G-Rf (20 mg/kg) as well as vehicle only or imipramine (20 mg/kg) as controls. Depression-like behavior of mice was evaluated using forced swimming test (FST) and tail suspension test (TST). We observed recovery of astroglial impairment and increased proliferative cells in the PFC and its accompanied change in the hippocampus by Western blot and immunohistochemistry to assess the effect of G-Rf.

Results

After injection of L-AAA into the PFC, mice showed increased immobility time in FST and TST and loss of astrocytes without significant neuronal change in the PFC. G-Rf–treated mice displayed significantly more decreased immobility time in FST and TST than did vehicle-treated mice, and their immobility time almost recovered to those of the sham mice and imipramine-treated mice. G-Rf upregulated glial fibrillary acidic protein (GFAP) expression and Ki-67 expression in the PFC reduced by L-AAA and also alleviated astroglial change in the hippocampus.

Conclusion

G-Rf markedly reversed depression-like behavioral changes and exhibited protective effect against the astrocyte ablation in the PFC induced by L-AAA. These protective properties suggest that G-Rf might be a therapeutic agent for major depressive disorders.

Formulation and Characterization of Novel Dry Suspension and Dry Emulsion of 20(S)-Protopanaxadiol

To improve the absorption of poorly water-soluble 20(S)-protopanaxadiol (20(S)-PPD), novel 20(S)-PPD-loaded redispersible dry suspension and dry emulsion were developed in this study. 20(S)-PPD dry suspension (PPD-DS) was prepared by enabling drug fully dispersed with suspending agent Avicel CL611 and solubilizer Poloxamer 188. 20(S)-PPD dry emulsion (PPD-DE) was prepared by employing oleic acid as oil phase, Cremophor RH-40 as surfactant, and n-butyl alcohol as co-surfactant. Both PPD-DS and PPD-DE were evaluated for their physicochemical characterization after being dispersed in distilled water. The in vivo pharmacokinetics was evaluated by UPLC-MS/MS. The droplet size of PPD-DS and PPD-DE was in the scope of 1446-1653 nm and 652.8-784.5 nm. The sedimentation volume ratios of PPD-DS and PPD-DE were both at value of 1. The zeta potential of PPD-DS and PPD-DE were from - 53.7 to - 70.4 mV and - 27.5 to - 34.5 mV, respectively, which indicated stable systems. PPD-DS and PPD-DE both achieved dramatically enhanced aqueous solubility and higher perfusion of 20(S)-PPD in rats' intestine. Although statistically, no oral bioavailability enhancements of 20(S)-PPD were achieved in PPD-DE and PPD-DS, there were some improvements in the pharmacokinetic behaviors. Especially, PPD-DS could be a promising drug delivery carrier for 20(S)-PPD with the advantages of long-term stability, dosing flexibility, and the convenience of administering to infants and to those who have difficulty swallowing tablets or capsules.

Research Progress in the Effect of Traditional Chinese Medicine for Invigoration on Neurotransmitter Related Diseases

Tonic traditional Chinese medicine is widely used in clinical practice and is categorized into four main drugs, namely, Qi-supplementing, Blood-enriching, Yin-nourishing, and Yang-tonifying. Neurotransmitters play a coordinating role in the nervous system, visceral function, and stress response. The excitation or suppression of the central nervous system is closely related to various diseases, such as insomnia, depression, Alzheimer's disease, Parkinson's disease, and perimenopausal syndrome. An increasing amount of evidence shows that Chinese tonic herb and its active ingredients can delay the occurrence and development of these diseases by modulating related neurotransmitters and their receptors, including norepinephrine (NE), serotonin (5-HT), dopamine (DA), acetylcholine (ACh), and γ-aminobutyric acid (GABA). In the present report, studies on the treatment of these neurotransmitter related diseases in relation to the application of tonic Chinese medicine are reviewed.

20(S)-protopanaxadiol regio-selectively targets androgen receptor: anticancer effects in castration-resistant prostate tumors

We have explored the effects of 20(S)-protopanaxadiol (aPPD), a naturally derived ginsenoside, against androgen receptor (AR) positive castration resistant prostate cancer (CRPC) xenograft tumors and have examined its interactions with AR. In silico docking studies for aPPD binding to AR, alongside transactivation bioassays and in vivo efficacy studies were carried out in the castration-resistant C4-2 xenograft model. Immunohistochemical (IHC) and Western blot analyses followed by evaluation of AR, apoptotic, cell cycle and proliferative markers in excised tumors was performed. The growth of established CRPC tumors was inhibited by 53% with aPPD and a corresponding decrease in serum PSA was seen compared to controls. The IHC data revealed that Ki-67 was significantly lower for aPPD treated tumors and was associated with elevated p21 and cleaved caspase-3 expression, compared to vehicle treatment. Furthermore, aPPD decreased AR protein expression in xenograft tumors, while significantly upregulating p27 and Bax protein levels. In vitro data supporting this suggests that aPPD binds to and significantly inhibits the N-terminal or the DNA binding domains of AR. The AR androgen binding site docking score for androgen (dihydrotestosterone) was −11.1, while that of aPPD was −7.1. The novel findings described herein indicate aPPD potently inhibits PCa in vivo partly via inhibition of a site on the AR N-terminal domain. This manifested as cell cycle arrest and concurrent induction of apoptosis via an increase in Bax, cleaved-caspase-3, p27 and p21 expression.

Panax Notoginseng Saponins: A Review of Its Mechanisms of Antidepressant or Anxiolytic Effects and Network Analysis on Phytochemistry and Pharmacology

Panax notoginseng (Burk) F. H. Chen, as traditional Chinese medicine, has a long history of high clinical value, such as anti-inflammatory, anti-oxidation, inhibition of platelet aggregation, regulation of blood glucose and blood pressure, inhibition of neuronal apoptosis, and neuronal protection, and its main ingredients are Panax notoginseng saponins (PNS). Currently, Panax notoginseng (Burk) F. H. Chen may improve mental function, have anti-insomnia and anti-depression effects, alleviate anxiety, and decrease neural network excitation. However, the underlying effects and the mechanisms of Panax notoginseng (Burk) F. H. Chen and its containing chemical constituents (PNS) on these depression-related or anxiety-related diseases has not been completely established. This review summarized the antidepressant or anxiolytic effects and mechanisms of PNS and analyzed network targets of antidepressant or anxiolytic actions with network pharmacology tools to provide directions and references for further pharmacological studies and new ideas for clinical treatment of nervous system diseases and drug studies and development. The review showed PNS and its components may exert these effects through regulating neurotransmitter mechanism (5-HT, DA, NE), modulation of the gamma-amino butyric acid (GABA) neurotransmission, glutamatergic system, hypo-thalamus-pituitary-adrenal (HPA) axis, brain-derived neurotrophic factor (BDNF), and its intracellular signaling pathways in the central nervous system; and produce neuronal protection by anti-inflammatory, anti-oxidation, or inhibition of neuronal apoptosis, or platelet aggregation and its intracellular signaling pathways. Network target analysis indicated PNS and its components also may have anti-inflammatory and anti-apoptotic effects, which leads to the preservation of brain nerves, and regulate the activity and secretion of nerve cells, exerting anti-depression and anxiolytic effects, which may provide new directions for further in-depth researches of related mechanisms.

Ginseng Extract G115 Attenuates Ethanol-Induced Depression in Mice by Increasing Brain BDNF Levels

The decrease of brain-derived neurotrophic factor (BDNF) has been reported in alcohol use disorder and major depression. The effective treatment of these comorbid diseases remains undiscovered. Nutraceutical products are therefore proposed as an alternative approach to overcome this challenge. Ginseng extract G115, the standardized extract of Panax ginseng, is a widely-used nutraceutical that is beneficial for various central nervous system disorders. This study aimed to determine the antidepressant effect of ginseng extract G115 in ethanol-treated mice models. Mice received either water, amitriptyline, or various doses of G115 (p.o.) followed by water or ethanol (i.p.) for 8 days. The antidepressant activity was evaluated using forced swimming test. BDNF levels were measured from hippocampal and prefrontal cortex tissues. The results demonstrated that the increase of immobility time in depressant mice induced by ethanol was reversed by both G115 and amitriptyline treatment. A significant increase of BDNF levels in the hippocampus and prefrontal cortex was observed in ethanol-treated mice receiving G115. Taken together, this study provides scientific information on the use of G115 as an antidepressant that could be further used as a dietary supplement in comorbid alcohol use and major depressive disorders.

Involvement of serotonergic, noradrenergic and dopaminergic systems in the antidepressant-like effect of ginsenoside Rb1, a major active ingredient of Panax ginseng C.A. Meyer

ETHNOPHARMACOLOGY RELEVANCE

Ginsenoside Rb1, a 20 (S)-protopanaxadiol, is a major active ingredient of Panax ginseng C.A. Meyer, which as the King of Chinese herbs, has been wildly used for the treatment of central nervous system diseases. Previous studies have shown that 20 (S)-protopanaxadiol possesses a novel antidepressant-like effect in the treatment of depression, whereas ginsenoside Rb1 in depression has been rarely reported.

AIM OF THE REVIEW

The present study was to investigate the antidepressant-like effect of ginsenoside Rb1 and its relevant mechanisms.

MATERIALS AND METHODS

The whole experiment was divided into two parts: one part we examined the antidepressant-like effect of ginsenoside Rb1 with open-field test (OFT), tail suspension test (TST), forced swim test (FST), 5-HTP induced head-twitch and reserpine response in mice, another part we used chronic unpredicted mild stress (CUMS) model to further explore the antidepressant-like effect of ginsenoside Rb1 with caffeine, fluoxetine and p-Chlorophenylalanine (PCPA) in rats. Furthermore, the levels of monoamine neurotransmitters of NE, 5-HT, DA and their metabolites 5-HIAA, DOPAC, HVA were all measured by ELISA kits after the CUMS protocol.

RESULTS

Our data indicated that 7 days treatment with ginsenoside Rb1 (4, 8, 10mg/kg, p.o.) significantly decreased immobility time in the FST and TST in mice, and played important roles in mice which were induced by 5-HTP (200mg/kg, i.p.) and reserpine (4mg/kg, i.p.). On the basis of CUMS model, 21 days treatment with ginsenoside Rb1 not only had effective interactions with caffeine (5mg/kg, i.p.), fluoxetine (1mg/kg, i.p.) and PCPA (100mg/kg, i.p.), but also significantly up-regulated the 5-HT, 5-HIAA, NE and DA levels in CUMS rats' brain, whereas HVA and DOPAC had no significant difference. Moreover, there was no alteration in spontaneous locomotion in any experimental group.

CONCLUSIONS

These results suggest that ginsenoside Rb1 exhibits significant antidepressant-like effect in behavioral tests, chronic animal model and drug interactions, its mechanisms mainly mediated by central neurotransmitters of serotonergic, noradrenergic and dopaminergic systems.

Panax ginseng exerts antidepressant-like effects by suppressing neuroinflammatory response and upregulating nuclear factor erythroid 2 related factor 2 signaling in the amygdala

Background

Depression is one of the most commonly diagnosed neuropsychiatric diseases, but the underlying mechanism and medicine are not well-known. Although Panax ginseng has been reported to exert protective effects in various neurological studies, little information is available regarding its antidepressant effects.

Methods

Here, we examined the antidepressant effect and underlying mechanism of P. ginseng extract (PGE) in a chronic restraint stress (CRS)-induced depression model in mice.

Results

Oral administration of PGE for 14 d decreased immobility (depression-like behaviors) time in forced swim and tail suspended tests after CRS induction, which corresponded with attenuation of the levels of serum adrenocorticotropic hormone and corticosterone, as well as attenuated c-Fos expression in the amygdala. PGE enhanced messenger RNA expression level of brain-derived neurotrophic factor but ameliorated microglial activation and neuroinflammation (the level of messenger RNA and protein expression of cyclooxygenase-2 and inducible nitric oxide synthase) in the amygdala of mice after CRS induction. Interestingly, 14-d treatment with celecoxib, a selective cyclooxygenase-2 inhibitor, and N_ω-nitro-L-arginine methyl ester hydrochloride, a selective inducible nitric oxide synthase inhibitor, attenuated depression-like behaviors after CRS induction. Additionally, PGE inhibited the upregulation of the nuclear factor erythroid 2 related factor 2 and heme oxygenase-1 pathways.

Conclusion

Taken together, our findings suggest that PGE exerts antidepressant-like effect of CRS-induced depression by antineuroinflammatory and antioxidant (nuclear factor erythroid 2 related factor 2/heme oxygenase-1 activation) activities by inhibiting the hypothalamo-pituitary-adrenal axis mechanism. Further studies are needed to evaluate the potential of components of P. ginseng as an alternative treatment of depression, including clinical trial evaluation.

Ginsenoside Rg3 exerts anti-depressive effect on an NMDA-treated cell model and a chronic mild stress animal model

Depression is a common mental disorder and a leading cause of disability. At its most severe, it can lead to suicide. Recently, there has been growing interest in the application of natural herbs for the prevention and treatment of depression. In this report, we found that the ginsenoside active component Rg3 has an apparent antidepressant effect. In N-methyl-d-aspartic acid (NMDA)-treated HT22 murine hippocampal neuronal cells, Rg3 recovered proliferation and inhibited apoptosis by altering the cell cycle. More interestingly, Rg3 led to apparent physiological behavior change in a chronic mild stress model as seen in forced swim, tail suspension, and sucrose preference tests. This effect was mediated by the phosphorylation of cAMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) signaling. This study provides direct evidence to support the antidepressant effects of ginsenoside Rg3, potentially indicating its application in the treatment of clinical depression.

Synthesis and Crystal Structure of Ocotillol-Type Metabolites Derived from (20R)-Protopanaxadiol

Four ocotillol-type (20R)-protopanaxadiol metabolites, (20R,24S)-20,24-epoxy-12β,25-dihydroxdammaran-3-one (M3), and (20R,24R)-20,24-epoxy-12β,25-dihydroxydammarane-3-one (M4), (20R,24S)-20,24-epoxy-3β,25-dihydroxydammaran-12-one (M9) and (20R,24R)-20,24-epoxy-3β,25-dihydroxydammaran-12-one (M10) are synthesised from (20R)-protopanaxadiol. Their structures are confirmed by HRMS, 1H NMR and 13C NMR. Moreover, the absolute configurations of M3 and M4 are confirmed by the X-ray single crystal diffraction.

Enhancing Saccharomyces cerevisiae reactive oxygen species and ethanol stress tolerance for high-level production of protopanoxadiol

Protopanaxadiol (PPD) is an active compound in Panax ginseng. Recently, an optimized PPD synthesis pathway contained a ROS releasing step (a P450-type PPD synthase, PPDS) was introduced into Saccharomyces cerevisiae. Here reported a synergistic effect of PPDS-CPR (CPR, cytochrome P450 reductase) uncoupling and ethanol stress on ROS releasing, which reduced cells viability. To build a robust strain, a cell wall integrity associated gene SSD1 was high-expressed to improve ethanol tolerance, and ROS level decreased for 24.7%. Then, regulating the expression of an oxidative stress regulation gene YBP1 decreased 75.2% of ROS releasing, and improved cells viability from 71.3±1.3% to 88.3±1.4% at 84h. Increased cells viability enables yeast to produce more PPD through feeding additional ethanol. In 5L fermenter, PPD production of W3a-ssPy reached to 4.25±0.18g/L (19.48±0.28mg/L/OD600), which is the highest yield reported so far. This work makes the industrial production of PPD possible by microbial fermentation.

Effects of ginseng on stress-related depression, anxiety, and the hypothalamic-pituitary-adrenal axis

Ginseng effectively regulates the immune response and the hormonal changes due to stress, thus maintaining homeostasis. In addition to suppressing the occurrence of psychological diseases such as anxiety and depression, ginseng also prevents stress-associated physiological diseases. Recent findings have revealed that ginseng is involved in adjusting the hypothalamic-pituitary-adrenal axis and controlling hormones, thus producing beneficial effects on the heart and brain, and in cases of bone diseases, as well as alleviating erectile dysfunction. Recent studies have highlighted the potential use of ginseng in the prevention and treatment of chronic inflammatory diseases such as diabetes, rheumatoid arthritis, and allergic asthma. However, the mechanism underlying the effects of ginseng on these stress-related diseases has not been completely established. In this review, we focus on the disease pathways caused by stress in order to determine how ginseng acts to improve health. Central to our discussion is how this effective and stable therapeutic agent alleviates the anxiety and depression caused by stress and ameliorates inflammatory diseases.

Design and synthesis of 28-hydroxy protopanaxadiol as a novel probe template

To explore the antitumour mechanism of 20(S)-protopanaxadiol (PPD) while maintaining its uncovered pharmacological active site 3-hydroxyl, 28-hydroxy protopanaxadiol (17), a small molecular probe template of PPD was first designed and synthesised based on the Baldwin's reaction. Thus, 28-hydroxyl of 17 was built successfully as a derivatized site of molecular probe's functional and report groups. The important intermediates and final product were confirmed by ESI-MS and nuclear magnetic resonance spectra with good yield. These studies provided a valuable basis for probe research of PPD.

Identification of Human UDP-Glucuronosyltransferase 1A4 as the Major Isozyme Responsible for the Glucuronidation of 20(S)-Protopanaxadiol in Human Liver Microsomes

20(S)-protopanaxadiol (PPD), one of the representative aglycones of ginsenosides, has a broad spectrum of pharmacological activities. Although phase I metabolism has been investigated extensively, information regarding phase II metabolism of this compound remains to be elucidated. Here, a glucuronidated metabolite of PPD in human liver microsomes (HLMs) and rat liver microsomes (RLMs) was unambiguously identified as PPD-3-O-β-d-glucuronide by nuclear magnetic resonance spectroscopy and high resolution mass spectrometry. The chemical inhibition and recombinant human UDP-Glucuronosyltransferase (UGT) isoforms assay showed that the PPD glucuronidation was mainly catalyzed by UGT1A4 in HLM, whereas UGT1A3 showed weak catalytic activity. In conclusion, PPD-3-O-β-d-glucuronide was first identified as the principal glucuronidation metabolite of PPD in HLMs, which was catalyzed by UGT1A4.

Formulation of 20(S)-protopanaxadiol nanocrystals to improve oral bioavailability and brain delivery

The aim of this study was to fabricate 20(S)-protopanaxadiol (PPD) nanocrystals to improve PPD's oral bioavailability and brain delivery. PPD nanocrystals were fabricated using an anti-solvent precipitation approach where d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) was optimized as the stabilizer. The fabricated nanocrystals were nearly spherical with a particle size and drug loading of 90.44 ± 1.45 nm and 76.92%, respectively. They are in the crystalline state and stable at 4°C for at least 1 month. More than 90% of the PPD could be rapidly released from the nanocrystals, which was much faster than the physical mixture and PPD powder. PPD nanocrystals demonstrated comparable permeability to solution at 2.52 ± 0.44×10(-5)cm/s on MDCK monolayers. After oral administration of PPD nanocrystals to rats, PPD was absorbed quickly into the plasma and brain with significantly higher Cmax and AUC0-t compared to those of the physical mixture. However, no brain targeting was observed, as the ratios of the plasma AUC0-t to brain AUC0-t for the two groups were similar. In summary, PPD nanocrystals are a potential oral delivery system to improve PPD's poor bioavailability and its delivery into the brain for neurodegenerative disease and intracranial tumor therapies in the future.

Phytochemical constituents as future antidepressants: a comprehensive review

Depression is a major mental disease that is ranked as the fourth leading cause of disability. In order to avoid unwanted adverse reactions, as well as improve efficacy, current researches are seeking alternatives to conventional antidepressants. Phytochemicals provide an extensive research area in antidepressant therapies. The aim of the present study is to comprehensively review neurological evidences demonstrating the efficacy of phytochemicals in depression. For this purpose, electronic databases were searched to collect all data on the antidepressant mechanisms of phytochemicals from 1966 up to 2015. Plant metabolites from different categories including polyphenols (flavonoids, phenolic acids, lignanes, coumarins), alkaloids, terpenes and terpenoids, saponins and sapogenins, amines, and carbohydrates were found to possess antidepressant activity. Naringenin, quercetin derivatives, eugenol, piperine, diterpene alkaloids, berberine, hyperforin, riparin derivatives, ginsenosides, as well as β-carboline alkaloids are among the most relevant ones. Naringenin has represented its antidepressant effect by elevation of serotonin (5-HT), norepinephrine, brain-derived neurotrophic factor (BDNF), and glucocorticoid receptors. Piperine demonstrated inhibition of monoamine oxidase enzymes, elevation of brain 5-HT and BDNF levels, and modulation of the hypothalamus-pituitary-adrenal axis. The serotonergic, noradrenergic, and dopaminergic effect of berberine has been proven in several studies. Quercetin derivatives have revealed antidepressant potential via elevating pro-opiomelanocortin and neuroprotective properties, as well as reduction of proinflammatory cytokines. Assessing the structure-activity relationship of highly potent antidepressant phytochemicals is suggested to find future natural, semisynthetic, or synthetic antidepressants. Further clinical studies are also necessary for confirmation of natural antidepressant efficacy and completion of their safety profile.

Antidepressant-like effects of ginsenosides: A comparison of ginsenoside Rb3 and its four deglycosylated derivatives, Rg3, Rh2, compound K, and 20(S)-protopanaxadiol in mice models of despair

Ginsenoside Rb3 has been proved to have antidepressant-like effects, which possesses 1 xylose and 3 glucose moieties with 20(S)-protopanaxadiol (PPD) as the aglycone. However, it is commonly accepted that orally ingested ginsenosides can be deglycosylated or partially deglycosylated into active derivatives by the intestinal bacteria. To identify potential antidepressant drug candidates, we compared the antidepressant-like activities between ginsenoside Rb3 and its four deglycosylated derivatives, Rg3, Rh2, compound K (C-K), and PPD. Effects of acute (1-day), short chronic (7-days), and longer chronic treatments (14-days) with these ginsenosides (50 and 100mg/kg, p.o.) on the behavioral changes in the forced swim test (FST), tail suspension test (TST) and open field test were investigated. Serum corticosterone and adrenocorticotropic hormone (ACTH) levels and mouse brain monoamine neurotransmitters 5-HT, NA and DA levels were measured using commercially available competitive enzyme-linked immunosorbent assay (ELISA) kits. Interestingly, C-K showed antidepressant-like activities similar to that of Rb3, and Rg3 displayed antidepressant-like effects at lower dosage and faster time, indicating it has better effects than Rb3, whereas Rh2 and PPD failed to show any effect. Our results also showed, unlike the positive control fluoxetine, Rb3, Rg3 and C-K significantly increased the NA levels in the brain regions of mice exposed to FST but did not affect the 5-HT and DA levels. Moreover, treatment with Rg3 could reverse swim stress-induced increased levels of serum ACTH and corticosterone. These results suggest that C-K and Rg3 are the active deglycosylated derivatives, especially the latter compound, which is more potent than Rb3 and exerts antidepressant-like effects by regulating NA, ACTH and corticosterone levels.

Protective effects of ginseng on neurological disorders

Ginseng (Order: Apiales, Family: Araliaceae, Genus: Panax) has been used as a traditional herbal medicine for over 2000 years, and is recorded to have antianxiety, antidepressant and cognition enhancing properties. The protective effects of ginseng on neurological disorders are discussed in this review. Ginseng species and ginsenosides, and their intestinal metabolism and bioavailability are briefly introduced. This is followed by molecular mechanisms of effects of ginseng on the brain, including glutamatergic transmission, monoamine transmission, estrogen signaling, nitric oxide (NO) production, the Keap1/Nrf2 adaptive cellular stress pathway, neuronal survival, apoptosis, neural stem cells and neuroregeneration, microglia, astrocytes, oligodendrocytes and cerebral microvessels. The molecular mechanisms of the neuroprotective effects of ginseng in Alzheimer’s disease (AD) including β-amyloid (Aβ) formation, tau hyperphosphorylation and oxidative stress, major depression, stroke, Parkinson’s disease and multiple sclerosis are presented. It is hoped that this discussion will stimulate more studies on the use of ginseng in neurological disorders.

20(S)-Protopanaxadiol induces human breast cancer MCF-7 apoptosis through a caspase-mediated pathway

20(S)-Protopanaxadiol (PPD), a ginsenoside isolated from Pananx quinquefolium L., has been shown to inhibit growth and proliferation in several cancer cell lines. The aim of this study was to evaluate its anticancer activity in human breast cancer cells. MCF-7 cells were incubated with different concentrations of 20(S)-PPD and cytotoxicity was evaluated by MTT assay. Occurrence of apoptosis was detected by DAPI and Annexin V-FITC/PI double staining. Mitochondrial membrane potential was measured with Rhodamine 123. The Bcl-2 and Bax expression were determined by Western blot analysis. Caspase activity was measured by colorimetric assay. 20(S)-PPD dose-dependently inhibited cell proliferation in MCF-7 cells, with an IC50 value of 33.3 μM at 24h. MCF-7 cells treated with 20(S)-PPD presented typical apoptosis, as observed by morphological analysis in cell stained with DAPI. The percentages of annexin V-FITC positive cells were 8.92%, 17.8%, 24.5% and 30.5% in MCF-7 cells treated with 0, 15, 30 and 60μM of 20(S)-PPD, respectively. Moreover, 20(S)-PPD could induce mitochondrial membrane potential loss, up-regulate Bax expression and down-regulate Bcl-2 expression. These events paralleled activation of caspase-9, -3 and PARP cleavage. Apoptosis induced by 20(S)-PPD was blocked by z-VAD-fmk, a pan-caspase inhibitor, suggesting induction of caspase-mediated apoptotic cell death. In conclusion, the 20(S)-PPD investigated is able to inhibit cell proliferation and to induce cancer cell death by a caspase-mediated apoptosis pathway.

Herbal Medicine for Anxiety, Depression and Insomnia

The prevalence and comorbidity of psychiatric disorders such as depression, anxiety and insomnia are very common. These well-known forms of psychiatric disorders have been affecting many people from all around the world. Herb alone, as well as herbal formula, is commonly prescribed for the therapies of mental illnesses. Since various adverse events of western medication exist, the number of people who use herbs to benefit their health is increasing. Over the past decades, the exploration in the area of herbal psychopharmacology has received much attention. Literatures showed a variety of herbal mechanisms of action used for the therapy of depression, anxiety and insomnia, involving reuptake of monoamines, affecting neuroreceptor binding and channel transporter activity, modulating neuronal communication or hypothalamic-pituitary adrenal axis (HPA) etc. Nonetheless, a systematic review on herbal pharmacology in depression, anxiety and insomnia is still lacking. This review has been performed to further identify modes of action of different herbal medicine, and thus provides useful information for the application of herbal medicine.