Phenylbutenoid dimers isolated from Zingiber purpureum exert neurotrophic effects on cultured neurons and enhance hippocampal neurogenesis in olfactory bulbectomized mice

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Transcriptome analysis of PC12 cells reveals that trans-banglene upregulates RT1-CE1 and downregulates abca1 in the neurotrophic pathway

Trans(t)-banglene and cis(c)-banglene possess neurotrophin-like activity in rat neurons. However, the molecular mechanisms underlying t-banglene-induced neurotrophic activity in rat and human neurons remain unclear. Here, we performed transcriptome analysis in PC12 cells, a rat adrenal gland pheochromocytoma cell line treated with t-banglene, using comprehensive RNA sequencing. The differentially expressed gene analysis of the sequencing data revealed that the expression of RT1 class I, locus CE1 (RT1-CE1) was upregulated, and that of ATP binding cassette subfamily A member 1 (abca1), myosin light chain 6, and hippocampus abundant transcript 1 was downregulated in t-banglene-treated PC12 cells, with statistically significant differences. We also confirmed the RT1-CE1 upregulation and abca1 downregulation in t-banglene-treated PC12 cells by reverse transcription quantitative real-time polymerase chain reaction. RT1-CEl is a major histocompatibility complex class I (MHCI) protein. ABCAl is a major cholesterol transporter that regulates efflux of intracellular cholesterol and phospholipids. Thus, our results suggest an exciting link between MHCI, cholesterol regulation, and neural development.

Structure-Activity Relationship and Bioactivity Studies of Neurotrophic trans-Banglene

The synthesis and bioactivity of neurotrophic banglenes and derivatives is described, establishing a structure-activity relationship which enables future mechanistic studies. Neuritogenesis assays indicate that (–) trans-banglene is the active enantiomer....

Phytochemicals and Bioactivities of Zingiber cassumunar Roxb

Zingiber cassumunar Roxb. (Zingiberaceae), is an important medicinal plant known as “Plai (Phlai)” in Thailand, “Bangle” in Indonesia, and “Bulei” in China. Traditionally, this plant has been used to treat inflammation, pain, and respiratory problems. The rhizomes are the primary part of the plant that has been used for medicinal purposes due to their constituents with therapeutic properties, including phenylbutenoids, curcuminoids, and essential oils. Since the 1970s, many studies have been conducted on the phytochemicals and bioactivities of Z. cassumunar to establish fundamental scientific evidence that supports its use in traditional medicine. The accumulated biological studies on the extracts, solvent fractions, and constituents of Z. cassumunar have described their diverse medicinal properties, including antioxidant, anti-inflammatory, anticancer, neuroprotective/neurotrophic, cosmeceutical, and antifungal/antimicrobial bioactivities. In this review, we summarize information on the phytochemicals of Z. cassumunar and the bioactivities of its extracts and constituents.

Potential bangle (Zingiber montanum J.König) rhizome extract as a supplement to prevent and reduce symptoms of Covid-19

The morbidity and mortality rates due to Covid-19 are increasing day by day, to overcome this, we urgently need a better treatment strategy, therefore various ways and strategies for this must be pursued. The purpose of the present review is to explain that the rhizome of bangle (Zingiber montanum) has great potential to increase antibodies and reduce symptoms of acute respiratory distress syndrome (ARDS), which also seems suitable for treating Covid-19. Method: This review is looking for the results of scientific research from various sources, regarding the efficacy of bangle (Zingiber montanum) rhizome which is strongly suspected to be able to prevent, and reduce the symptoms that occur in COVID-19. The results showed that the bangle rhizome extract had activity as immunomodulatory, antiviral and reduced symptoms such as what happened in COVID-19. Conclusion: Bangle rhizome extract has dozens of nutritious substances and has multifunctional activities, and it can be postulated that among the benefits of bangle rhizome extract it is able to prevent and reduce symptoms that occur in Covid-19, and preclinical studies and clinical studies are needed to prove this postulate.

Design and synthesis of dual active neovibsanin derivatives based on a chemical structure merging method

A hybrid compound consisting of neovibsanin and trans-banglene was designed according to a structure merging method and synthesized via a sequence of key steps including a Diels-Alder cycloaddition, stereoselective alkynylation, and intramolecular oxa-Michael addition reaction. The biological activity of the synthetized acetal compound and its hemiacetal analogue was investigated in PC12 cells. These studies revealed that the designed hybrid compounds displayed neuritogenic activity. Furthermore, a relatively strong neurite outgrowth promoting activity was observed in the presence of NGF. These results suggest that the designed hybrid compound exhibited a dual activity.

Metabolite Profiling of Javanese Ginger Zingiber purpureum and Identification of Antiseizure Metabolites via a Low-Cost Open-Source Zebrafish Bioassay-Guided Isolation

The rhizomes of Zingiber purpureum, "Bangle", were investigated for its antiseizure properties using a streamlined and cost-effective zebrafish screening strategy and a mouse epilepsy assay. Its hexane extract demonstrated strong antiseizure activity in zebrafish epilepsy assay and was, therefore, selected for bioactivity-guided fractionation. Twelve compounds (1-12) were isolated, and two bioactive phenylbutenoids, trans- (11) and cis-banglene (12), reduced up to 70% of pentylenetetrazole (PTZ)-induced seizures. These compounds showed moderate activity against PTZ-induced seizures in a mouse epilepsy assay. To understand the specificity of Z. purpureum active compounds, its chemical profile was compared to that of Z. officinale. Their composition was assessed by differential metabolite profiling visualized by a molecular network, which revealed only vanillin derivatives and terpenoids as common metabolites and gave a comprehensive view of Z. purpureum composition. This study demonstrates the efficacy of a streamlined zebrafish epilepsy assay, which is therefore suitable for routine screening in phytochemistry laboratories.

Indonesian Ginger (Bangle) Extract Promotes Neurogenesis of Human Neural Stem Cells through WNT Pathway Activation

Indonesian ginger (Zingiber purpureum Rosc.), also known as Bangle, exhibits neurotrophic effects on cultured murine cortical neurons and in the adult mouse brain, but the underlying mechanisms remain unknown. Here, using human fetal neural stem cells (hfNSCs) as a model system for in vitro human neurogenesis, we show that Bangle extracts activate canonical WNT/β-catenin signaling. Bangle extract-treatment of hfNSCs not only promoted neuronal differentiation, but also accelerated neurite outgrowth from immature neurons. Furthermore, Bangle extracts induced expression of neurogenic genes and WNT signaling-target genes, and facilitated the accumulation of β-catenin in nuclei of hfNSC. Interestingly, altered histone modifications were also observed in Bangle-treated hfNSCs. Together, these findings demonstrate that Bangle contributes to hfNSC neurogenesis by WNT pathway and epigenetic regulation.

Chemistry and Neurotrophic Activities of (-)-Talaumidin and Its Derivatives

(–)-Talaumidin (1), a 2,5-biaryl-3,4-dimethyltetrahydrofuran lignan isolated from Aristolochia arcuata Masters, exhibits significant neurite-outgrowth promotion and neuroprotection in primary cultured rat cortical neurons and in NGF-differentiated PC12 cells. The first enantioselective total synthesis of 1 was achieved by a flexible and reliable synthetic pathway involving an Evans asymmetric aldol reaction, as well as a stereocontrolled hydroboration and Friedel–Crafts arylation, to construct the four contiguous chiral centers on the tetrahydrofuran (THF) ring of 1. In order to investigate the stereochemistry–activity relationship of 1, a systematic synthesis of all diastereomers of 1 was accomplished by applying the synthetic strategy used for natural product 1. The evaluation of neurite-outgrowth promotion by all of the synthesized diastereomers indicated that the (–)-(1S,2R,3S,4R)-isomer 1e was significantly more active than naturally occurring 1. Additionally, we established a synthetic methodology for talaumidin derivatives that could be used to prepare a variety of analogs in a few steps and on a large scale. The synthesized racemic analog rac-1e (56a) exhibited neurite-outgrowth promoting activity in NGF-differentiated PC12 cells to the same degree as the optically active (–)-1e, revealing that a relative configuration bearing all-cis- substituents is important for potent neurotrophic activity, whilst the absolute configuration does not affect activity. Fourteen analogs based on (±)-56a were prepared via the same synthetic methodology. Among them, 56b with a methylenedioxy group on both benzene rings was found to exhibit the most significant neurite outgrowth promotion. In addition, 56a and 56b induced regeneration of the mouse optic nerve in vivo, and their activity was higher than that of talaumidin, as well as their in vitro measured activity. Furthermore, the structure–activity relationship of 56b indicated that the two benzene rings were essential structures, and that the methyl groups on the THF ring could enhance the neurotrophic activity. This result suggests that the two benzene rings of the talaumidin derivatives are essential structures for neurotrophic activity, while the two methyl groups on the THF ring can enhance neurite-outgrowth activity. Finally, it was observed that 1 and derivatives 56a and 56b exhibited potent regenerative activity in the injured mouse optic nerve in vivo.

Safety Assessment of Bangle (Zingiber purpureum Rosc.) Rhizome Extract: Acute and Chronic Studies in Rats and Clinical Studies in Human

Bangle (Zingiber purpureum Rosc.) rhizome extract (BRE) contains phenylbutenoid dimers (banglenes), which exert neurotrophic effects and possess the potential capability to regenerate hippocampal neurons in mice. The acute and chronic oral toxicities of BRE powder were evaluated in Sprague-Dawley rats. A dose of BRE powder was estimated to be higher than 2000 mg/kg containing BRE 534 mg/kg as minimum lethal dose in a single-dose oral toxicity study. The no-observed-adverse-effect-level for the BRE powder was 1000 mg/kg/day (BRE 267 mg/kg) in the 90 day oral toxicity study. Four week clinical studies of BRE tablets in humans suggested that the ingestion of BRE tablets within 850 mg/man/day (BRE 227 mg/man/day) was safe for at least 1 month and in a usual manner. The C _max, t _max, and AUC of cis- and trans-(E)-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-enes (c- and t-banglenes) were calculated after the ingestion of BRE tablets (BRE 227 mg) and were 17.73 and 22.61 ng/mL, 1.8 and 1.8 h, and 71.47 and 95.53 ng/mL/h, respectively.

Sarcodonin G Derivatives Exhibit Distinctive Effects on Neurite Outgrowth by Modulating NGF Signaling in PC12 Cells

Sarcodonin G, one of the cyathane diterpenoids isolated from the mushroom Sarcodon scabrosus, possesses pronounced neurotrophic activity but ambiguous mechanical understanding. In this work, sarcodonin G was chosen as a lead compound to prepare a series of 19- O-benzoyl derivatives by semisynthesis and their neuritogenic activities were evaluated. 6 and 15 (10 μM) were investigated with opposite effects in PC12 cells. 6 exhibited a superior activity to sarcodonin G by promoting NGF-induced neurite outgrowth, while 15 showed an inhibitory effect. Supportingly, 6 and 15 (20 μM) significantly induced and suppressed neurite extension in primary cultured rat cortical neurons, respectively. In mechanism, the two derivatives were revealed to influence NGF-induced neurite outgrowth in PC12 cells through the regulation of PKC-dependent and -independent ERK/CREB signaling as well as the upstream TrkA receptor phosphorylation. Furthermore, a possible pattern of interaction among NGF, 6/15 and TrkA was presented using molecular simulations. It revealed that 6/15 may contribute to the stabilization of the NGF-TrkAd5 complex by establishing several hydrophobic and hydrogen-bond interactions with NGF and TrkA, respectively. Taken together, 6 and 15 modulate PKC-dependent and -independent ERK/CREB signaling pathways possibly by influencing the binding affinity of NGF to the receptor TrkA, and finally regulate neurite outgrowth in PC12 cells.

Studies on Extraction Conditions to Increase the Content of Neurotrophic Compounds in the Bangle (Zingiber purpureum) Extract

To develop the Javanese ginger Bangle ( Zingiber purpureum), which contains neurotrophic phenylbutenoid compounds named banglenes 1 and 2, as a functional food additive for protection of neurodegenerative disease, we investigated conversion method from 3 to 1 and 2 under practical conditions available in food processing steps. After several trials, we found that dimerization of 3 proceeded smoothly under refluxing EtOH/H2O (1/3) in the presence of ubiquinone (0.1 eq) in sealed tube, giving rise to 1 and 2 in 54% yield. When this condition was applied for 70% EtOH extract of bangle, content of 1 and 2 in the extract was increased 2-fold by 2.1%.

The olfactory bulbectomized rat as a model of depression: The hippocampal pathway

In rodents, the removal of the olfactory bulbs (OBs), i.e. olfactory bulbectomy (OBX), results in numerous alterations in neurotransmitter, endocrine and immune systems, as well as behavioral changes, similar to those observed in depressed patients. Because the behavioral deficits induced in OBX animals are reversed after repeated administration of antidepressants, this is a model often used to test the effectiveness of putative antidepressant agents. Recent evidence suggests that OBX results in the dysfunction of various cellular processes within the hippocampus, including decreases in dentate gyrus neurogenesis, disruption in long-term potentiation in CA1 and CA3 subregions and neuronal atrophy in the CA1 subregion, along with downstream markers, all of which are consistent with abnormal neuronal activity in the hippocampus of clinically depressed populations. Moreover, repeated administration of novel natural and synthetic antidepressant compounds can improve certain aspects of depression-like behavior and hippocampal function. In an effort to bring together the existing literature, this review will focus on the mechanisms by which proposed pharmaceuticals impact hippocampal-dependent processes and behavior.

[Search of Neurotrophin-mimic Natural Products for Prevention and Treatment of Neurodegenerative Disease]

As part of our continuing studies on neurotrophin-mimic active compounds in natural products, we investigated the chemical constituents of the pericarps of Illicium jiadifengpi and the roots of Indonesian ginger Zingiber purpureum, resulting in the isolation of new seco-prezizaane-type sesquiterpenoid 1 and phenylbutenoid dimer 3-4 and two new curcuminoids 5-6. The MeOH extract of I. jiadifengpi was fractionated, leading to the isolation of compound 1. Compound 1 significantly enhanced neurite outgrowth in primary cell cultures of fetal rat cortical neurons. It is noteworthy that compound 1 has potential significantly to promote differentiation of multipotent neural stem cell line (MEB5 cells) into neurons. Additionally, we investigated the MeOH extract of the root of Bangle (Z. purpureum) that exhibited neuritogenesis activity in PC12 cells at 25 μg/mL, resulting in the isolation of neurotrophic phenylbutenoid dimers 3-4 and new compounds 5-6. Compounds 3 and 4 were found not only significantly to induce neurite sprouting of PC12 cells but also to increase the neurite length and number of neurites in primary cultured rat cortical neurons, and also showed protective activity against cell death caused by deprivation of serum. Furthermore, chronic treatment with these compounds enhanced hippocampal neurogenesis in dementia model olfactory bulbectomized (OBX) mice. Compounds 5 and 6 had significant NGF-potentiating effects on PC12 cells whereas compound 5 enhanced prevention of amyloid β (Aβ) 42 aggregation.

Bangle (Zingiber purpureum) Improves Spatial Learning, Reduces Deficits in Memory, and Promotes Neurogenesis in the Dentate Gyrus of Senescence-Accelerated Mouse P8

Bangle (Zingiber purpureum) is a tropical ginger that is used as a spice in Southeast Asia. Phenylbutenoid dimers isolated from Bangle have exhibited neurotrophic effects in primary cultured rat cortical neurons and PC12 cells. Furthermore, chronic treatment with phenylbutenoid dimers enhances hippocampal neurogenesis in olfactory bulbectomized mice. In this study, we investigated the effects of Bangle extract on behavior and hippocampal neurogenesis in vivo. SAMP8 mice, which are an established model for accelerated aging, with age-related learning and memory impairments, were given a Bangle-containing diet for 1 month, and subsequent behavioral tests and immunohistochemistry for Ki67, a proliferating cell marker, were performed. We found that the Bangle-containing diet improved spatial learning and memory deficits in the Morris water maze and significantly increased the numbers of Ki67-positive cells in the dentate gyrus of the SAMP8 mice. In addition, the Bangle extract exhibited a neurotrophin-like activity as indicated by the induction of neurite sprouting in PC12 cells. Our results suggest that Bangle is beneficial for the prevention of age-related progression of cognitive impairment.

Novel neurotrophic phenylbutenoids from Indonesian ginger Bangle, Zingiber purpureum

Two new curcuminoids 1 and 2, and a new phenylbutenoid dimer 3, were isolated from Bangle (Zingiber purpureum). Their structures were determined on the basis of comprehensive spectroscopic data and their biogenetic pathway. Compounds 1 and 2 are the first example of curcumin coupled with phenylbutenoid. Compounds 1 and 2 promoted neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 1 to 10 μM. In addition, compound 1 was found to accelerate the prevention of Aβ42 aggregation.

In vitro and in vivo evaluation of phenylbutenoid dimers as inhibitors of P-glycoprotein

The expression of P-glycoprotein (P-gp), an ATP-dependent efflux transporter, is closely associated with the failure of chemotherapy and drug absorption. Two synthesized optically active phenylbutenoid dimers, 3S-(3,4-dimethoxyphenyl)-4R-{(E)-3,4-dimethoxystyryl}cyclohex-1-ene (1) and 3R-(3,4-dimethoxyphenyl)-4S-{(E)-3,4-dimethoxystyryl}cyclohex-1-ene (2), were tested for their P-gp inhibitory effects by measuring cellular accumulation and efflux of daunomycin in P-gp-overexpressed human breast cancer cells (MCF-7/ADR). Compound 2 significantly increased the accumulation of daunomycin (539%) and decreased the efflux of this compound (55.4%), and similar results were observed for 1. ATPase assays and Western blot analysis were performed to identify the mechanisms by which compounds 1 and 2 inhibit P-gp. In addition, changes in the pharmacokinetic profile of paclitaxel coadministered with 2 in rats were evaluated. Paclitaxel (25 mg/kg) when orally administered with 2 (5 mg/kg) improved its relative bioavailability by 185%. Compound 2 effectively improved cellular accumulation by reducing the efflux of daunomycin and significantly enhanced oral exposure to paclitaxel. Therefore, compound 2 may be useful for improving oral exposure and cellular availability of drugs that are also substrates of P-gp.

Evaluation of constituents of Piper retrofractum fruits on neurotrophic activity

Three new compounds, 1-3, together with 22 known compounds, were isolated from the fruits of Piper retrofractum. The structures of the new compounds were elucidated on the basis of spectroscopic data analysis and comparison with literature values. Compound 1 was found to enhance the neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10 μM.