Comparison of interactions between alpha-lactalbumin and three protopanaxadiol ginsenosides: Impacts on the structure and antitumor properties

In this research, interactions between α-lactalbumin (ALA) and three protopanaxadiol ginsenosides [20(S)-Rg3, 20(S)-Rh2, and 20(S)-PPD] were compared to explore the effects of similar ligand on structure and cytotoxicity of ALA. Multi-spectroscopy revealed the binding between ALA and ginsenoside changed the conformation of ALA, which related to different structures and solubility of ligands. Scanning electron microscope illustrated that all ALA-ginsenoside complexes exhibited denser structures via hydrophobic interactions. Additionally, the cytotoxic experiments confirmed that the cytotoxicity of ginsenoside was enhanced after binding with ALA. Molecular docking showed all three ginsenosides were bound to the sulcus depression region of ALA via hydrogen bonding and hydrophobic interaction. Furthermore, molecular dynamics simulation elucidated the precise binding sites and pertinent system properties. Among all three composite systems, 20(S)-Rh2 had optimal binding affinity. These findings enhanced understanding of the synergistic utilization of ALA and ginsenosides as functional ingredients in food, medicine, and cosmetics.

Triphenylphosphonium-linked derivative of hecogenin with enhanced antiproliferative activity: Design, synthesis, and biological evaluation

Hecogenin (HCG), a steroidal sapogenin, possesses good antitumor properties. However, the application of HCG for cancer treatment has been hindered primarily by its moderate potency. In this study, we incorporated triphenylphosphonium cation (TPP+) at the C-3 and C-12 positions through different lengths of alkyl chains to target mitochondria and enhance the efficacy and selectivity of the parent compound. Cytotoxicity screening revealed that most of the target compounds exhibited potent antiproliferative activity against five human cancer cell lines (MKN45, A549, HCT-116, MCF-7, and HepG2). Structure-activity relationship studies indicated that the TPP+ group significantly enhanced the antiproliferative potency of HCG. Among these compounds, 3c demonstrated remarkable potency against MKN45 cells with an IC50 value of 0.48 μM, significantly more effective than its parent compound HCG (IC50 > 100 μM). Further investigations into the mechanism of action revealed that 3c induced apoptosis of MKN45 cells through the mitochondrial pathway. In a zebrafish xenograft model, 3c inhibited the proliferation of MKN45 cells. Overall, these results suggest that 3c, with potent antiproliferative activity, may serve as a valuable scaffold for developing new antitumor agents.

Protopanaxatriol activates EGFR and HER2 to strengthen the molecules of skin protection in human keratinocytes

BACKGROUND

Protopanaxatriol (PPT) is an important ginsenoside produced by ginseng, a tonic plant used in many areas. PPT has beneficial effects against many disease states including inflammation, diabetes, and cancer. However, PPT's protective effects on skin integrity have been rarely studied. Previously, we reported that PPT can maintain skin moisture through activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) pathways. However, the cellular targets for enhancing skin moisturizing effects via PPT are still unknown.

PURPOSE

We wanted to identify the upstream targets of PPT on upregulating moisturizing factor (HAS-2) expression.

STUDY DESIGN

We investigated which upstream proteins can be directly stimulated by PPT to modulate NF-κB, MAPKs and other signaling cascades. Then, the targeted proteins were overexpressed to check the relationship with HAS-2. Next, the cellular thermal shift assay (CETSA) was conducted to check the relationship between targeted proteins and PPT.

METHODS

A human keratinocyte HaCaT were employed to measure the levels of moisturizing factors and the signaling proteins activated by PPT. Transfection conditions were established with DNA constructs expressing epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) and their mutants prepared by site-directed mutagenesis. Further investigation on molecular mechanisms was conducted by RT-PCR, luciferase reporter gene assay, CETSA, or Western blot.

RESULTS

We found that PPT can activate the phosphorylation of EGFR and HER2. These stimulations caused Src phosphorylation, which resulted in the activation of phosphoinositide 3-kinases (PI3K)/pyruvate dehydrogenase kinase 1 (PDK1)/protein kinase B (AKT)/NF-κB and MAPKs signaling cascades. Additionally, EGFR and HER2 activation resulted in phosphorylation of signal transducer and activator of transcription 3 (STAT3) and calcium/calmodulin-dependent protein kinase II (CaMKII). This induced the AMP-activated protein kinase alpha (AMPKα) signaling pathway. Additionally, PPT blocked peroxisome proliferator activated receptor gamma (PPARγ), which also contributed to the phosphorylation of Src.

CONCLUSION

Overall, we first found that PPT offers excellent protection of the skin barrier and hydrogen supply in keratinocytes. Moreover, growth factor receptors such as EGFR and HER2 were revealed to be central enzymes to be directly targeted by PPT. These results suggest a potentially valuable role as a cosmetic ingredient.

Synthesis, antioxidant, antiproliferative activity, molecular docking and DFT studies of novel isoxazole derivatives of diosgenin, a steroidal sapogenin from Dioscorea deltoidea

Diosgenin [25R-spirost-5-en-3β-ol], isolated from Dioscorea deltoidea was used as a starting material for synthesizing its various isoxazole derivatives. A library of fifteen isoxazole analogues (DG1-DG15) were synthesised via modification at the C-3 hydroxyl group. The resulting analogues were fully characterized by spectral techniques and evaluated for their antioxidant and anticancer activity against four breast cancer cell lines; MDA-MB-231, MDA-MB-468, MCF-7, and 4 T1, using MTT assay. Molecular docking studies were carried out for all analogues with EGFR protein (PDB id: 6LUD) to check their activity by inhibiting EGFR protein, which is an effective strategy for cancer cell death. Furthermore, DFT studies were carried out for four analogues. Among all analogues, compound DG6 and DG9 showed the highest scavenging activity and compound DG9 exhibited a maximum cytotoxic effect on the MDA-MB-468 and MCF-7 cell lines with an IC50 value of 6.25 μg/mL and 6.81 μg/mL, while compound DG5 was the least potent (IC50 25.89 μg/mL). Molecular docking results revealed that DG8 and DG9 afforded the highest binding energy of -14.33 and - 14.71 kcal/mol, respectively for the target EGFR protein. These results demonstrate the potential of diosgenin analogues as drug candidates for breast cancer therapy. Furthermore, DFT studies revealed that the molecules are more polarizable and have smaller energy gap between their HOMO and LUMO orbitals, the smallest being of DG9 (3.221 eV) and hence are more reactive.

Diosgenin, a Natural Steroidal Sapogenin, Alleviates the Progression of Diabetic Retinopathy in Diabetic Mice

BACKGROUND/AIM

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and a major cause of blindness in working-age adults. Diosgenin (DG), a natural steroidal sapogenin extracted from fenugreek seeds and wild yam roots, has hypolipidemic, hypoglycemic, anticancer, and anti-inflammatory properties. Given its pharmacological effects, we speculated that DG may be a promising treatment for DR. Therefore, this study was aimed at evaluating the effectiveness of DG in preventing or slowing DR progression in a mouse model (+Lepr^db/+Lepr^db strain) of type 2 diabetes (T2D).

MATERIALS AND METHODS

DG (5.0 mg/kg body weight) or phosphate-buffered saline (PBS) was administered to 8-week-old T2D mice via oral gavage daily for 24 weeks. Paraffin-embedded eye tissues from the mice were collected and stained with hematoxylin and eosin to evaluate retinal histopathology. Apoptosis-related proteins BCL2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), and cleaved caspase-3 were evaluated by western blotting of mouse retinas.

RESULTS

Body weight was slightly reduced in the DG-treated group; however, glucose levels were not markedly different between the DG- and PBS-treated groups. Total retinal thickness, thickness of the photoreceptor and outer nuclear layers, and loss of ganglion cells significantly improved in the retina of the DG-treated T2D mice compared with those in the PBS-treated T2D mice. Cleaved caspase-3 level significantly decreased in the retina of the DG-treated T2D mice. Conclusion: DG alleviates DR pathology and exerts a protective effect on the T2D mouse retina. The inhibitory effects of DG on DR may involve mechanisms of the anti-apoptotic pathway.

Anti-inflammatory Activity: In silico and In vivo of Sapogenins Present in Agave brittoniana subsp. brachypus (Trel.)

BACKGROUND

Agave brittoniana subsp. brachypus is an endemic plant of Cuba, which contains different steroidal sapogenins with anti-inflammatory effects. This work aims to develop computational models which allow the identification of new chemical compounds with potential anti-inflammatory activity.

METHODS

The in vivo anti-inflammatory activity was evaluated in two rat models: carrageenaninduced paw edema and cotton pellet-induced granuloma. In each study, we used 30 Sprague Dawley male rats divided into five groups containing six animals. The products isolated and administrated were fraction rich in yuccagenin and sapogenins crude.

RESULTS

The obtained model, based on a classification tree, showed an accuracy value of 86.97% for the training set. Seven compounds (saponins and sapogenins) were identified as potential antiinflammatory agents in the virtual screening. According to in vivo studies, the yuccagenin-rich fraction was the greater inhibitor of the evaluated product from Agave.

CONCLUSION

The evaluated metabolites of the Agave brittoniana subsp. Brachypus showed an interesting anti-inflammatory effect.

Concise synthesis of E/F ring spiroethers from tigogenin. Carbaanalogs of steroidal sapogenins and their biological activity

A four-step synthesis of five- and six-membered E/F ring spiroethers from tigogenin has been developed. An efficient strategy that features bis-Grignard reaction of dinorcholanic lactone with appropriate bis(bromomagnesio)alkanes followed by acid-mediated spirocyclization was employed to construct a new class of steroid compounds having E and F ring junction as an oxa-carbacyclic system. The synthesized carbaanalogs interact with liposomes and albumin, and also exhibit antibacterial and antifungal activity, demonstrating their pharmacological potential.

Transgenic Rice Seed Extracts Exert Immunomodulatory Effects by Modulating Immune-Related Biomarkers in RAW264.7 Macrophage Cells

Protopanaxadiol (PPD), a native active triterpenoid present in Panax ginseng, has been reported to exert immune-related effects. We previously created PPD-producing transgenic rice by introducing the P. ginseng protopanaxadiol synthase and dammarenediol-II synthase genes into Dongjin rice. In the present study, the seeds of the T₄ generation of this transgenic rice were tested for their immunomodulatory effects in RAW264.7 macrophage cells. Treatment with transgenic rice seed extract in RAW264.7 cells (i) significantly enhanced nitric oxide (NO) production in a dose-dependent manner without any cytotoxicity (up to 100 µg/mL), (ii) upregulated the expression of immune-related genes and increased production of the inflammation mediator prostaglandin E₂ (PGE₂), and (iii) activated nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) by promoting the phosphorylation of NF-κB p65, p38 MAPK, and c-Jun N-terminal protein kinase (JNK). In lipopolysaccharide (LPS)-treated RAW264.7 cells used to mimic the inflammation condition, treatment with transgenic rice seed extract significantly reduced NO production, proinflammatory cytokine expression, and PGE₂ production, all of which are LPS-induced inflammation biomarkers, by inhibiting the phosphorylation of NF-κB p65, p38 MAPK, and JNK. Collectively, these results indicate that PPD-producing transgenic rice has immunomodulatory effects.

Production of Prosaikogenin F, Prosaikogenin G, Saikogenin F and Saikogenin G by the Recombinant Enzymatic Hydrolysis of Saikosaponin and their Anti-Cancer Effect

The saponins of Bupleurum falcatum L., saikosaponins, are the major components responsible for its pharmacological and biological activities. However, the anti-cancer effects of prosaikogenin and saikogenin, which are glycoside hydrolyzed saikosaponins, are still unknown due to its rarity in plants. In this study, we applied two recombinant glycoside hydrolases that exhibit glycoside cleavage activity with saikosaponins. The two enzymes, BglPm and BglLk, were cloned from Paenibacillus mucilaginosus and Lactobacillus koreensis, and exhibited good activity between 30-37 °C and pH 6.5-7.0. Saikosaponin A and D were purified and obtained from the crude B. falcatum L. extract using preparative high performance liquid chromatography technique. Saikosaponin A and D were converted into saikogenin F via prosaikogenin F, and saikogenin G via prosaikogenin G using enzyme transformation with high β-glycosidase activity. The two saikogenin and two prosaikogenin compounds were purified using a silica column to obtain 78.1, 62.4, 8.3, and 7.5 mg of prosaikogenin F, prosaikogenin G, saikogenin F, and saikogenin G, respectively, each with 98% purity. The anti-cancer effect of the six highly purified saikosaponins was investigated in the human colon cancer cell line HCT 116. The results suggested that saikosaponins and prosaikogenins markedly inhibit the growth of the cancer cell line. Thus, this enzymatic technology could significantly improve the production of saponin metabolites of B. falcatum L.

Anti-inflammatory and modulatory effects of steroidal saponins and sapogenins on cytokines: A review of pre-clinical research

BACKGROUND

Saponins are glycosides which, after acid hydrolysis, liberate sugar(s) and an aglycone (sapogenin) which can be triterpenoid or steroidal in nature. Steroidal saponins and sapogenins have attracted significant attention as important natural anti-inflammatory compounds capable of acting on the activity of several inflammatory cytokines in various inflammatory models.

PURPOSE

The aim of this review is to collect preclinical in vivo studies on the anti-inflammatory activity of steroidal saponins through the modulation of inflammatory cytokines.

STUDY DESIGN AND METHODS

This review was carried out through a specialized search in three databases, that were accessed between September and October, 2021, and the publication period of the articles was not limited. Information about the name of the steroidal saponins, the animals used, the dose and route of administration, the model of pain or inflammation used, the tissue and experimental method used in the measurement of the cytokines, and the results observed on the levels of cytokines was retrieved.

RESULTS

Forty-five (45) articles met the inclusion criteria, involving the saponins cantalasaponin-1, α-chaconine, dioscin, DT-13, lycoperoside H, protodioscin, α-solanine, timosaponin AIII and BII, trillin, and the sapogenins diosgenin, hecogenin, and ruscogenin. The surveys were carried out in seven different countries and only articles between 2007 and 2021 were found. The studies included in the review showed that the saponins and sapogenins were anti-inflammatory, antinociceptive and antioxidant and they modulate inflammatory cytokines mainly through the Nf-κB, TLR4 and MAPKs pathways.

CONCLUSION

Steroidal saponins and sapogenins are promising compounds in handling of pain and inflammation for the development of natural product-derived drugs. However, it is necessary to increase the methodological quality of preclinical studies, mainly blinding and sample size calculation.

Cycloastragenol, a Triterpenoid Saponin, Regulates Oxidative Stress, Neurotrophic Dysfunctions, Neuroinflammation and Apoptotic Cell Death in Neurodegenerative Conditions

Here, we have unveiled the effects of cycloastragenol against Aβ (Amyloid-beta)-induced oxidative stress, neurogenic dysfunction, activated mitogen-activated protein (MAP) kinases, and mitochondrial apoptosis in an Aβ-induced mouse model of Alzheimer's disease (AD). The Aβ-induced mouse model was developed by the stereotaxic injection of amyloid-beta (5 μg/mouse/intracerebroventricular), and cycloastragenol was given at a dose of 20 mg/kg/day/p.o for 6 weeks daily. For the biochemical analysis, we used immunofluorescence and Western blotting. Our findings showed that the injection of Aβ elevated oxidative stress and reduced the expression of neurogenic markers, as shown by the reduced expression of brain-derived neurotrophic factor (BDNF) and the phosphorylation of its specific receptor tropomyosin receptor kinase B (p-TrKB). In addition, there was a marked reduction in the expression of NeuN (neuronal nuclear protein) in the Aβ-injected mice brains (cortex and hippocampus). Interestingly, the expression of Nrf2 (nuclear factor erythroid 2-related factor 2), HO-1 (heme oxygenase-1), p-TrKB, BDNF, and NeuN was markedly enhanced in the Aβ + Cycloastragenol co-treated mice brains. We have also evaluated the expressions of MAP kinases such as phospho c-Jun-N-terminal kinase (p-JNK), p-38, and phospho-extracellular signal-related kinase (ERK1/2) in the experimental groups, which suggested that the expression of p-JNK, p-P-38, and p-Erk were significantly upregulated in the Aβ-injected mice brains; interestingly, these markers were downregulated in the Aβ + Cycloastragenol co-treated mice brains. We also checked the expression of activated microglia and inflammatory cytokines, which showed that cycloastragenol reduced the activated microglia and inflammatory cytokines. Moreover, we evaluated the effects of cycloastragenol against mitochondrial apoptosis and memory dysfunctions in the experimental groups. The findings showed significant regulatory effects against apoptosis and memory dysfunction as revealed by the Morris water maze (MWM) test. Collectively, the findings suggested that cycloastragenol regulates oxidative stress, neurotrophic processes, neuroinflammation, apoptotic cell death, and memory impairment in the mouse model of AD.

Inhibitory activities of 20(R, S)-protopanaxatriol against epidermal growth factor receptor tyrosine kinase

As major metabolites of protopanaxatriol-type ginsenosides, 20(R, S)-protopanaxatriol [20(R, S)-PPT] display multiple bioactivities. This work aimed to investigate the inhibitory activities of 20(R, S)-PPT against epidermal growth factor receptor tyrosine kinase and the potential mechanism. 20(R, S)-PPT inhibited the proliferation of HepG2 cells in a dose-dependent manner and blocked cell cycle progression at G1/G0 phase. Then 20(R, S)-PPT were found to influence the protein expressions involved in epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) signaling pathway. Molecular docking suggested that 20(R, S)-PPT could bind to the active sites of all target proteins in EGFR-MAPK pathway. It is worth noting that 20(R, S)-PPT showed stronger binding capacities with EGFR, compared with other proteins. Hence, this work further investigated the binding interactions and binding stabilities between 20(R, S)-PPT and EGFR. Both hydrophobic interactions and hydrogen bonds contributed to the 20(R, S)-PPT-EGFR binding. In addition, the in vitro inhibitory activities of 20(R, S)-PPT against EGFR tyrosine kinase were observed in a homogeneous time-resolved fluorescence assay, with the IC₅₀ values of 24.10 ± 0.17 and 33.19 ± 0.19 μM respectively. Taken together with the above results, both of 20(R)-PPT and 20(S)-PPT might serve as potential EGFR tyrosine kinase inhibitors.

Cycloastragenol inhibits Aβ1-42-induced blood-brain barrier disruption and enhances soluble Aβ efflux in vitro

This study aimed to evaluate the effect Cycloastragenol (CAG), a triterpenoid saponin isolated from the Radix astragali, on Aβ-induced BBB damage. An immortalized endothelial cell line (bEnd.3) was employed to mimic a BBB. The Western blot, TUNEL staining, Flow cytometric analysis and Enzyme-linked immunosorbent assay were performed. The present results showed that CAG (10, 50, 75 μM) can alleviate oligomer Aβ_1-42 induced bEnd.3 cell apoptosis and increase tight junction scaffold proteins expression. The result also indicated that CAG increased soluble Aβ efflux across BBB via upregulation of the P-gp and downregulation of RAGE expression.[Formula: see text].

Transcriptomic analysis reveals responses to Cycloastragenol in Arabidopsis thaliana

Cycloastragenol (CAG), a molecule isolated from ‘Astragalus membranaceus’, stimulates the telomerase activity and cell proliferation significantly. It has been proven that CAG has the ability to prevent some diseases in humans. In this study, we aimed to figure out the CAG effects on the different signaling mechanisms in plants and to broadly analyze the genome-wide transcriptional responses in order to demonstrate CAG as a new key molecule that can potentially help plants to overcome different environmental stresses. RNA-seq strategy was employed to assess the transcriptional profiles in A. thaliana calli. Our work primarily focused on an overall study on the transcriptomic responses of A. thaliana to CAG. A total of 22593 unigenes have been detected, among which 1045 unigenes associated with 213 GO terms were differentially expressed and were assigned to 118 KEGG pathways. The up-regulated genes are principally involved in cellular and metabolic processes in addition to the response to a stimulus. The data analysis revealed genes associated with defense signaling pathways such as cytochrome P450s transporter, antioxidant system genes, and stress-responsive protein families were significantly upregulated. The obtained results can potentially help in better understanding biotic and/or abiotic tolerance mechanisms in response to CAG.

New 20(S)-protopanaxadiol type saponins from the leaves of Panax notoginseng and their potential anti-inflammatory activities

Through the combination of various chromatographies, 11 new 20(S)-protopanaxadiol (PPD) type saponins, named as notoginsenosides NL-E₁ - NL-E₄ (1-4), NL-F₁ (5), NL-F₂ (6), NL-G₁ (7), NL-G₂ (8), NL-H₁ - NL-H₃ (9-11) were obtained from the leaves of Panax notoginseng. Their structures were ascertained based on the extensive spectroscopic methods and chemical reactions. Meanwhile, the 20(S)-PPD type saponins with aglycone, (20S,24ζ)-3β,12β,20,24,25-pentahydroxy dammarane, was only found from the leaves of P. notoginseng. The characteristic could be used to distinguish the extracts of P. notoginseng leaves from its other medicinal parts such as roots, rhizomes, flowers or seeds. Furthermore, the nitric oxide (NO) inhibitory activities of all compounds were examined in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. As a result, compounds 2-7, 10 could exert NO inhibitory activity at 25 μM without cytotoxicity. Moreover, the inhibitory activities of them were in dose-dependent manner at 1, 10, and 25 μM. Especially, notoginsenoside NL-F₂ (6) still possessed strong biological activity at 1 μM.

Dammarane sapogenins attenuates stress-induced anxiety-like behaviors by upregulating ERK/CREB/BDNF pathways

Dammarane sapogenins (DS), an extract derived from ginseng by alkaline hydrolysis of total ginsenosides, possesses high pharmacological activity and higher bioavailability than ginsenosides. The present study was designed to investigate the anxiolytic-like effects of DS in a mouse model of chronic social defeat stress (CSDS). DS (40 and 80 mg/kg) significantly ameliorated social avoidance and anxiety-like behavior in four test models of CSDS, showing increased time in the interaction zone in the social interaction test and in the center of the field in the open field test, an increased percentage of entries and open arm time in the elevated plus maze, and reduced latency to eat in the novelty-suppressed feeding test. Biochemical analyses showed that DS significantly reduced serum corticosterone levels and increased brain concentration of neurotransmitter 5-HT and noradrenaline in CSDS mice. Treatment with DS significantly upregulated BDNF (brain-derived neurotrophic factor), p-CREB/CREB and p-ERK1/2/ERK1/2 protein expression in the hippocampus and prefrontal cortex of CSDS mice. Collectively, these results suggest that DS exerts anxiolytic-like effects in CSDS model mice and the action is mediated, at least in part, by modulating the HPA (hypothalamic-pituitary-adrenal) axis and monoamine neurotransmitter levels, and via ERK/CREB/BDNF signaling pathway.

Steroidal saponins and sapogenins from fenugreek and their inhibitory activity against α-glucosidase

The seed of Trigonella foenum-graecum L. (fenugreek) has been reported to be rich in saponins, especially the dioscin or diosgenin, which are natural anti-diabetic agents with relatively low toxicity. Thus, the present study was to purify the saponins and sapogenins from fenugreek and to evaluate their α-glucosidase inhibitory activity in vitro. As a result, 33 steroidal saponins and sapogenins were isolated, including six undescribed ones and 27 previously known molecules. Among them, compounds 10, 12, 17, 22 and 29 were five 25R and 25S isomer mixtures of spirostanol saponins or sapogenins. The structures of compound 1-6 were established by 1D and 2D NMR spectroscopic analyses, high-resolution mass spectrometry, and chemical evidence. Compared to the positive control, sapogenins 26, 27, 14 and saponins 18 and 23 considerably inhibited α-glucosidase at IC₅₀ values of 15.16, 8.98, 7.26, 5.49 and 14.01 μM, respectively. These results support the therapeutic potential of fenugreek in the treatment of diabetes with saponins and sapogenins as the active constituents.

Ginsenoside metabolite 20(S)-protopanaxatriol from Panax ginseng attenuates inflammation-mediated NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C.A. Meyer (Araliaceae), has been used in traditional medicine for preventive and therapeutic purposes in Asian countries. One of the active ginsenoside metabolites, 20(S)-Protopanaxatriol (PPT), has been associated with diverse pharmacological effects, including anti-inflammatory properties.

AIM OF THE STUDY

Although the capacity of PPT as an anti-inflammatory agent has been studied, this study aimed to explore the intrinsic mechanism of PPT in regulating inflammasome activation-mediated inflammatory responses in experimental models.

MATERIALS AND METHODS

Lipopolysaccharide (LPS)-primed peritoneal macrophages in vitro was used to study the role of PPT on inflammasome activation. LPS-induced septic shock and monosodium urate (MSU)-induced murine peritonitis models were employed for in vivo evaluations.

RESULTS

PPT attenuated NLRP3 inflammasome activation and also reduced ASC oligomerization, leading to attenuation of interleukin (IL)-1β secretion. Further, PPT inhibited IL-1β secretion in both LPS-induced septic shock and MSU-induced mouse peritonitis models.

CONCLUSIONS

This study revealed that ginsenoside metabolite PPT, inhibits inflammation-mediated inflammasome activation and supported the traditional use of ginseng in treating various inflammatory disorders.

Bifidobacteria-Fermented Red Ginseng and Its Constituents Ginsenoside Rd and Protopanaxatriol Alleviate Anxiety/Depression in Mice by the Amelioration of Gut Dysbiosis

Gut dysbiosis is closely connected with the outbreak of psychiatric disorders with colitis. Bifidobacteria-fermented red ginseng (fRG) increases the absorption of ginsenoside Rd and protopanxatriol into the blood in volunteers and mice. fRG and Rd alleviates 2,4,6-trinitrobenzenesulfonic acid-induced colitis in mice. Therefore, to understand the gut microbiota-mediated mechanism of fRG against anxiety/depression, we examined the effects of red ginseng (RG), fRG, ginsenoside Rd, and protopanaxatriol on the occurrence of anxiety/depression, colitis, and gut dysbiosis in mice. Mice with anxiety/depression were prepared by being exposed to two stressors, immobilization stress (IS) or Escherichia coli (EC). Treatment with RG and fRG significantly mitigated the stress-induced anxiety/depression-like behaviors in elevated plus maze, light-dark transition, forced swimming (FST), and tail suspension tasks (TST) and reduced corticosterone levels in the blood. Their treatments also suppressed the stress-induced NF-κB activation and NF-κB+/Iba1+ cell population in the hippocampus, while the brain-derived neurotrophic factor (BDNF) expression and BDNF+/NeuN+ cell population were increased. Furthermore, treatment with RG or fRG suppressed the stress-induced colitis: they suppressed myeloperoxidase activity, NF-κB activation, and NF-κB+/CD11c+ cell population in the colon. In particular, fRG suppressed the EC-induced depression-like behaviors in FST and TST and colitis more strongly than RG. fRG treatment also significantly alleviated the EC-induced NF-κB+/Iba1+ cell population and EC-suppressed BDNF+/NeuN+ cell population in the hippocampus more strongly than RG. RG and fRG alleviated EC-induced gut dysbiosis: they increased Bacteroidetes population and decreased Proteobacteria population. Rd and protopanaxatriol also alleviated EC-induced anxiety/depression and colitis. In conclusion, fRG and its constituents Rd and protopanaxatriol mitigated anxiety/depression and colitis by regulating NF-κB-mediated BDNF expression and gut dysbiosis.

Exploring the impact of a naturally occurring sapogenin diosgenin on underlying mechanisms of Ca2+ movement and cytotoxicity in human prostate cancer cells

Literature has shown that diosgenin, a naturally occurring sapogenin, inducedcytotoxic effects in many cancer models. This study investigated the effect of diosgenin on intracellular Ca²⁺ concentration ([Ca²⁺ ]i) and cytotoxicity in PC3 human prostate cancer cells. Diosgenin (250-1000 μM) caused [Ca²⁺ ]i rises which was reduced by Ca²⁺ removal. Treatment with thapsigargin eliminated diosgenin-induced [Ca²⁺ ]i increases. In contrast, incubation with diosgeninabolished thapsigargin-caused [Ca²⁺ ]i increases. Suppression of phospholipase C with U73122 eliminated diosgenin-caused [Ca²⁺ ]i increases. Diosgenin evoked Mn²⁺ influx suggesting that diosgenin induced Ca²⁺ entry. Diosgenin-induced Ca²⁺ influx was suppressed by PMA, GF109203X, and nifedipine, econazole, or SKF96365. Diosgenin (250-600 μM) concentration-dependently decreased cell viability. However, diosgenin-induced cytotoxicity was not reversed by chelation of cytosolic Ca²⁺ with BAPTA/AM. Together, diosgenin evoked [Ca²⁺ ]i increases via Ca²⁺ release and Ca²⁺ influx, and caused Ca²⁺ -non-associated deathin PC3 cells. These findings reveal a newtherapeutic potential of diosgenin for human prostate cancer.

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.

Structure and Activity of the Camellia oleifera Sapogenin Derivatives on Growth and Biofilm Inhibition of Staphylococcus aureus and Escherichia coli

Sapogenin is the main block of Camellia oleifera saponin, which was purified and structurally modified by the C₂₈ acylation reaction to synthesize 19 new derivatives. The growth and biofilm inhibition of Staphylococcus aureus and Escherichia coli was measured to evaluate their antibacterial effects. A three-dimensional quantitative structure-activity relationship (3D-QSAR) assay indicated that the antibacterial activities were significantly enhanced after sapogenin was modified with an aromatic ring or heterocyclic ring and electron-withdrawing substituents at the meta or para position. Among them, the derivative of sapogenin with a 2-mercapto-4-methyl-5-thiazolyl acetyl group obviously destroyed bacterial biofilm and made bacteria lysis. 3D-QSAR provides practical information for the structural design of sapogenin derivatives with strong antibacterial activity, and the C. oleifera sapogenin derivative 28-O-(2-mercapto-4-methyl-5-thiazolyl)-3β,16α,21β,22α-O-tetrahydroxy-oleantel-2-ene-23-aldehyde (S-16) is an effective candidate as an antibacterial agent for the prevention of bacterial resistance against antibiotics.

Preparation And Antibacterial Effects Of Carboxymethyl Chitosan-Modified Photo-Responsive Camellia Sapogenin Derivative Cationic Liposomes

BACKGROUND

Bacterial resistance to antibiotics is a persistent and intractable problem. The sapogenin isolated from the seeds of Camellia oleifera can inhibit antibiotic-resistant bacteria after structural modification.

PURPOSE

This study aims to improve sapogenin's antibacterial activity and avoid bacterial resistance based on nano-preparation with photo responsiveness.

METHODS

The liposome shell material of carboxymethyl chitosan-phosphatidyl ethanolamine (CMC-PE) was prepared using amidation reaction, and photo-responsive cationic (PCC) liposomes containing Camellia sapogenin derivative (CSD) and photosensitizer pheophorbide-a were prepared by film dispersion method. Encapsulation efficiency, drug loading, zeta potential, particle size distribution, morphology and stability of the PCC liposomes were determined by HPLC, particle size analyzer, transmission electron microscopy (TEM) and fluorescence microscopy. Photo-responsive release of CSD in the PCC liposomes was determined by laser (0.5 mW/cm2) at 665 nm. Antibacterial activity of the PCC liposomes with or without irradiation was analyzed by MIC50, MBC, MBIC50, and bacterial morphology to evaluate the antibacterial effects on amoxicillin resistant Escherichia coli and Staphylococcus aureus.

RESULTS

Size distribution, zeta potential, encapsulation efficiency and drug loading of the PCC liposomes were 189.23 ± 2.12 nm, 18.80 ± 1.57 mV, 83.52 ± 1.53% and 2.83 ± 0.05%, respectively. The PCC liposomes had higher storage stability and gastrointestinal stability, and no obvious hemolytic toxicity to rabbit red blood cells and no cytotoxicity after incubation with Hela cells. The photosensitizer pheophorbide-a was uniformly dispersed in the phospholipid layer of the PCC liposomes and increased the CSD release after irradiation. The PCC liposomes could bind to bacteria and impaired their morphology and structure, and had significant bactericidal effect on amoxicillin resistant E. coli and S. aureus.

CONCLUSION

The photo-responsive PCC liposomes are efficient antibacterial agents for avoidance of bacterial resistance against antibiotics.

In vitro and in silico evaluation of stereoselective effect of ginsenoside isomers on platelet P2Y12 receptor

BACKGROUND

P2Y₁₂ receptor (P2Y₁₂R) is a newly discovered Gi-coupled ADP receptor that plays critical role in platelet function. Ginsenosides are the main constituents responsible for most of pharmacological actions of ginseng, especially cardio-cerebrovascular protective efficacy that is closely related to the influence on platelet function.

HYPOTHESIS/PURPOSE

To explore stereoselective effect of naturally abundant ginsenoside isomers, including the C-20 epimers of protopanaxadiol (PPD), protopanaxatriol (PPT), and their glycosides Rg2, Rg3, Rh1, Rh2 on P2Y₁₂R in platelets.

STUDY DESIGN/METHODS

Both in vitro assay and in silico molecular docking study were performed to investigate the stereoselective effects.

RESULTS

In vitro assay using washed rat platelets revealed differential effects of ginsenoside isomers on ADP-induced platelet aggregation with the direction and degree of action varying with chemical structures. More to the point, the ginsenoside 20S-Rh2 but not its 20R-epimer was found to be the only one that could significantly promote in vitro platelets aggregation induced by ADP. The correlation analysis demonstrated that ginsenosides may have impact on P2Y₁₂R related platelet functions through a cAMP-dependent pathway. Molecular docking stimulation further indicated that ginsenoside isomers could be potent substrate of P2Y₁₂R with differential protein-ligand interaction that would be responsible for the stereoselective efficacy of C-20 ginsenoside epimers. Hydrogen bonding with Asp266 via the C-20 hydroxyl may provide ginsenosides with promoting effect on ADP-induced platelets aggregation, whereas interactions with Tyr105 could contribute to the promotion of inhibitory efficacy.

CONCLUSION

Ginsenosides are potent P2Y₁₂R substrate with stereoselective effects on P2Y₁₂R-related platelet function, which result from their chemical diversity and are closely related to the different interaction ways as P2Y₁₂R ligand.

Dammarane sapogenins alleviates depression-like behaviours induced by chronic social defeat stress in mice through the promotion of the BDNF signalling pathway and neurogenesis in the hippocampus

Chronic social defeat stress (CSDS) is a widely used behavioural paradigm of psychosocial stress that can be used to research the pathogenesis of depression and seek antidepressant drugs. Dammarane sapogenins (DS), the deglycosylated product of ginsenosides, has a wide range of biological activities, including immunomodulatory, antifatigue, antitumour and antidepressant activities. However, whether DS has antidepressant-like effects in a CSDS mouse model remains unknown. Therefore, the present study was conducted to evaluate the antidepressant properties of DS in CSDS mice and its underlying mechanisms. The results showed that the oral administration of DS (40 and 80 mg/kg) increased the time spent in the interaction zone in the social interaction test and the sucrose intake in the sucrose preference test, decreased the latency in the novelty-suppressed feeding test, and reduced the immobility time in both the tail suspension test and forced swimming test. Biochemical analyses of brain tissue and serum showed that DS treatment significantly decreased serum corticosterone levels and enhanced brain monoamine neurotransmitter levels in CSDS mice. In addition, an impairment in hippocampal neurogenesis that paralleled a reduced BDNF level in the hippocampus was observed in the mice that were subjected with CSDS for 3 weeks, while treatment with DS reversed these changes. Moreover, DS treatment significantly upregulated BDNF, pTrkB/TrkB, pAkt/Akt, pPI3K/PI3K, pCREB/CREB, pERK1/2/ERK1/2 and pmTOR/mTOR protein expression in the hippocampus. In conclusion, our results showed that DS exerts antidepressant-like effects in mice with CSDS-induced depression, that the effects may be mediated by the normalization of monoamine neurotransmitter levels, the prevention of HPA axis dysfunction and the impairment of hippocampal neurogenesis, and that this occurs partly through the ability of DS to enhance BDNF expression by increasing the TrkB/CREB/ERK pathway and the PI3K/AKT/mTOR pathway.

The protective effect of cycloastragenol on aging mouse circadian rhythmic disorder induced by d-galactose

Aging process in mammals is associated with a decline in amplitude and a long period of circadian behaviors which are regulated by a central circadian regulator in the suprachiasmatic nucleus (SCN) and local oscillators in peripheral tissues. It is unclear whether enhancing clock function can retard aging. Using fibroblasts expressing per2::lucSV and senescent cells, we revealed cycloastragenol (CAG), a natural aglycone derivative from astragaloside IV, as a clock amplitude enhancing small molecule. CAG could activate telomerase to antiaging, but no reports focused on its effects on circadian rhythm disorders in aging mice. Here we analyze the potential effects of CAG on d-galactose-induced aging mice on the circadian behavior and expression of clock genes. For this purpose, CAG (20 mg/kg orally), was administered daily to d-galactose (150 mg/kg, subcutaneous) mice model of aging for 6 weeks. An actogram analysis of free-running activity of these mice showed that CAG significantly enhances the locomotor activity. We further found that CAG increase expressions of per2 and bmal1 genes in liver and kidney of aging mouse. Furthermore, CAG enhanced clock protein BMAL1 and PER2 levels in aging mouse liver and SCN. Our results indicated that the CAG could restore the behavior of circadian rhythm in aging mice induced by d-galactose. These data of present study suggested that CAG could be used as a novel therapeutic strategy for the treatment of age-related circadian rhythm disruption.

Estrogen receptors modulate ectonucleotidases activity in hippocampal synaptosomes of male rats

Extracellular adenine nucleotides and nucleosides, such as adenosine-5'-triphosphate (ATP) and adenosine, are among least investigated signaling factors that participate in 17β-estradiol (E2)-mediated synaptic rearrangements in rodent hippocampus. Their levels in the extrasynaptic space are tightly controlled by ecto-nucleoside triphosphate diphosphohydrolases1-3 (NTPDase1-3)/ecto-5'-nucleotidase (eN) enzyme chain. Therefore, the aim of the present study was to get closer insight in the E2-induced decrease in NTPDase and eN activity in the hippocampal synaptic compartment of male rats and to identify estradiol receptors (ERs i.e. ERα, ERβ or GPER1) responsible for the observed effects of E2. In this study we show indiscriminate participation of estradiol receptor α (ERα), -β (ERβ) and G- protein coupled estrogen receptor 1 (GPER1) in the mediation of E2 actions in hippocampal synaptosomes of male rats. Synaptic NTPDase1-3 activities are modulated only through activation of ERβ, while activation of ERα, -β and/or non-classical GPER1 decreases synaptic eN activity. Since both ATP and adenosine function as neuromodulators in the hippocampal networks, influencing its function, profound knowledge of mechanisms by which ectonucleotidases are regulated/modulated is of great importance.

Cycloastragenol can negate constitutive STAT3 activation and promote paclitaxel-induced apoptosis in human gastric cancer cells

BACKGROUND

Cycloastragenol (CAG), a triterpene aglycone is commonly prescribed for treating hypertension, cardiovascular disease, diabetic nephropathy, viral hepatitis, and various inflammatory-linked diseases.

HYPOTHESIS

We investigated CAG for its action on signal transducer and activator of transcription 3 (STAT3) activation cascades, and its potential to sensitize gastric cancer cells to paclitaxel-induced apoptosis.

METHODS

The effect of CAG on STAT3 phosphorylation and other hallmarks of cancer was deciphered using diverse assays in both SNU-1 and SNU-16 cells.

RESULTS

We observed that CAG exhibited cytotoxic activity against SNU-1 and SNU-16 cells to a greater extent as compared to normal GES-1 cells. CAG predominantly caused negative regulation of STAT3 phosphorylation at tyrosine 705 through the abrogation of Src and Janus-activated kinases (JAK1/2) activation. We noted that CAG impaired translocation of STAT3 protein as well as its DNA binding activity. It further decreased cellular proliferation and mediated its anticancer effects predominantly by causing substantial apoptosis rather than autophagy. In addition, CAG potentiated paclitaxel-induced anti-oncogenic effects in gastric tumor cells.

CONCLUSIONS

Our results indicate that CAG can function to impede STAT3 activation in human gastric tumor cells and therefore it may be a suitable candidate agent for therapy of gastric cancer.

Synthesis and In Vitro Anti-inflammatory Activity of C20 Epimeric Ocotillol-Type Triterpenes and Protopanaxadiol

Ginseng is a perennial herb that contains various medicinal substances. The major active constituents of ginseng are ginsenosides, which have multifarious biological activities. Some pharmacological activities are closely dependent on the stereoisomers derived from the configuration at C20. In this study, the in vitro anti-inflammatory activity of C20 epimeric ocotillol-type triterpenes (2, 3, 9: , and 10: ) and protopanaxadiol [20(S/R)-protopanaxadiol] were investigated. Epimers 2: and 3: were prepared starting from 20(S)-protopanaxadiol. Epimers 9: and 10: were synthesized from 20(R)-3-acetylprotopanaxadiol (7: ). The anti-inflammatory activity of 2, 3, 9, 10: , 20(S)-protopanaxadiol, and 20(R)-protopanaxadiol was evaluated in cultured mouse macrophage RAW 264.7 cells. The MTT assay was used to measure the cytotoxicity. RAW 264.7 cells were stimulated by lipopolysaccharide to release the inflammatory mediators nitric oxide, prostaglandin E₂, TNF-α, and interleukin-6 and anti-inflammatory mediator interleukin-10. The effect of the compounds on the overproduction of nitric oxide, prostaglandin E₂, TNF-α, interleukin-6, and interleukin-10 was determined using Griess and ELISA methods. The results demonstrated that the in vitro anti-inflammatory activities of C20 epimeric ocotillol-type triterpenes and protopanaxadiol were different. Both the 20S-epimers (2: and 3: ) and 20R-epimers (9: and 10: ) inhibited the release of inflammatory mediator nitric oxide, while mainly the 20S-epimers inhibited the release of inflammatory mediator prostaglandin E₂, and the 20R-epimers inhibited the release of inflammatory cytokine TNF-α. Both the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] and 20R-epimers [9, 10: , and 20(R)-protopanaxadiol] inhibited the release of inflammatory cytokine interleukin-6, but mainly the 20S-epimers [2, 3: , and 20(S)-protopanaxadiol] increased the release of anti-inflammatory mediator interleukin-10.

Inhibitory effects of cycloastragenol on abdominal aortic aneurysm and its related mechanisms

BACKGROUND AND PURPOSE

Abdominal aortic aneurysm (AAA) is a degenerative disease affecting human health, but there are no safe and effective medications for AAA therapy. Cycloastragenol (CAG), derived from Astragali Radix, has various pharmacological effects. However, whether CAG can protect against AAA remains elusive. In this study, we investigated whether CAG has an inhibitory effect on AAA and its related mechanism.

EXPERIMENTAL APPROACH

The AAA mouse model was induced by incubating the abdominal aorta with elastase. CAG was administered by gavage at different doses beginning on the same day or 14 days after inducing AAA to explore its preventive or therapeutic effects respectively. The preventive effects of CAG on AAA were verified in another AAA mouse model induced by angiotensin II in ApoE-/- mouse. In vitro experiments were implemented on rat vascular smooth muscle cells (VSMCs) stimulated by TNF-α.

KEY RESULTS

Compared to the control AAA model group, CAG (125 mg·kg-1 body weight day-1 ) reduced the incidence of AAA, the dilatation of aorta and elastin degradation in media in both mouse models of AAA. CAG suppressed the inflammation, oxidation, phenotype switch and apoptosis in TNF-α-stimulated VSMCs, ameliorated the expression and activity of MMPs and decreased the activation of the ERK/JNK signalling pathway. CAG also inhibited the degradation of elastin in TNF-α-stimulated VSMCs.

CONCLUSION AND IMPLICATIONS

CAG presents protective effects against AAA through down-regulation of the MAPK signalling pathways and thus attenuates inflammation, oxidation, VSMC phenotype switch and apoptosis and the expression of MMPs as well as increasing elastin biosynthesis.

Efflux excretion of bisdemethoxycurcumin-O-glucuronide in UGT1A1-overexpressing HeLa cells: Identification of breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins 1 (MRP1) as the glucuronide transporters

Bisdemethoxycurcumin (BDMC) was a natural curcuminoid with many bioactivities present in turmeric (Curcuma longa L.). However, the disposition mechanisms of BDMC via uridine 5'-diphospho-glucuronosyltransferase (UGT) metabolism still remain unclear. Therefore, we aimed to determine the potential efflux transporters for the excretion of BDMC-O-glucuronide. Herein, chemical inhibition assays (Ko143, MK571, dipyridamole, and leukotriene C4) and biological inhibition experiments including stable knocked-down of breast cancer resistance protein (BCRP), multidrug resistance-associated proteins (MRPs) transporters were both performed in a HeLa cell line stably overexpressing UGT1A1 established previously. The results indicated that Ko143 (5 and 20 μM) caused a marked reduction in excretion rate (18.4-55.6%) and elevation of intracellular BDMC-O-glucuronide (28.8-48.1%), whereas MK-571 (5 and 20 μM) resulted in a significant decrease in excretion rate (6.2-61.6%) and increase of intracellular BDMC-O-glucuronide (maximal 27.1-32.6%). Furthermore, shRNA-mediated silencing of BCRP transporter led to a marked reduction in the excretion rate (21.1-36.9%) and an obvious elevation of intracellular glucuronide (24.9%). Similar results were observed when MRP1 was partially silenced. In addition, MRP3 and MRP4 silencing both displayed no obvious changes on the excretion rate and intracellular levels of glucuronide. In conclusion, chemical inhibition and gene silencing results both indicated that generated BDMC-O-glucoside were excreted primarily by the BCRP and MRP1 transporters. © 2018 BioFactors, 44(6):558-569, 2018.

Integrated Chemical and Transcriptomic Analysis Reveals the Distribution of Protopanaxadiol- and Protopanaxatriol-Type Saponins in Panax notoginseng

Panax notoginseng is famous for its important therapeutic effects and commonly used worldwide. The active ingredients saponins have distinct contents in different tissues of P. notoginseng, and they may be related to the expression of key genes in the synthesis pathway. In our study, high-performance liquid chromatography results indicated that the contents of protopanaxadiol-(Rb1, Rc, Rb2, and Rd) and protopanaxatriol-type (R1, Rg1, and Re) saponins in below ground tissues were higher than those in above ground tissues. Clustering dendrogram and PCA analysis suggested that the below and above ground tissues were clustered into two separate groups. A total of 482 and 882 unigenes were shared in the below and above ground tissues, respectively. A total of 75 distinct expressions of CYPs transcripts (RPKM ≥ 10) were detected. Of these transcripts, 38 and 37 were highly expressed in the below ground and above ground tissues, respectively. RT-qPCR analysis showed that CYP716A47 gene was abundantly expressed in the above ground tissues, especially in the flower, whose expression was 31.5-fold higher than that in the root. CYP716A53v2 gene was predominantly expressed in the below ground tissues, especially in the rhizome, whose expression was 20.1-fold higher than that in the flower. Pearson's analysis revealed that the CYP716A47 expression was significantly correlated with the contents of ginsenoside Rc and Rb2. The CYP716A53v2 expression was associated with the saponin contents of protopanaxadiol-type (Rb1 and Rd) and protopanaxatriol-type (R1, Rg1, and Re). Results indicated that the expression patterns of CYP716A47 and CYP716A53v2 were correlated with the distribution of protopanaxadiol-type and protopanaxatriol-type saponins in P. notoginseng. This study identified the pivotal genes regulating saponin distribution and provided valuable information for further research on the mechanisms of saponin synthesis, transportation, and accumulation.

Cycloartane-type sapogenol derivatives inhibit NFκB activation as chemopreventive strategy for inflammation-induced prostate carcinogenesis

Chronic inflammation is associated to 25% of cancer cases according to epidemiological data. Therefore, inhibition of inflammation-induced carcinogenesis can be an efficient therapeutic approach for cancer chemoprevention in drug development studies. It is also determined that anti-inflammatory drugs reduce cancer incidence. Cell culture-based in vitro screening methods are used as a fast and efficient method to investigate the biological activities of the biomolecules. In addition, saponins are molecules that are isolated from natural sources and are known to have potential for tumor inhibition. Studies on the preparation of analogues of cycloartane-type sapogenols (9,19-cyclolanostanes) have so far been limited. Therefore we have decided to direct our efforts toward the exploration of new anti-tumor agents prepared from cycloastragenol and its production artifact astragenol. The semi-synthetic derivatives were prepared mainly by oxidation, condensation, alkylation, acylation, and elimination reactions. After preliminary studies, five sapogenol analogues, two of which were new compounds (2 and 3), were selected and screened for their inhibitory activity on cell viability and NFκB signaling pathway activity in LNCaP prostate cancer cells. We found that the astragenol derivatives 1 and 2 as well as cycloastragenol derivatives 3, 4, and 5 exhibited strong inhibitory activity on NFκB signaling leading the repression of NFκB transcriptional activation and suppressed cell proliferation. The results suggested that these molecules might have significant potential for chemoprevention of prostate carcinogenesis induced by inflammatory NFκB signaling pathway.

Antidepressant effects of dammarane sapogenins in chronic unpredictable mild stress-induced depressive mice

Depression is a common, dysthymic, and psychiatric disorder, resulting in enormous social and economic burden. Dammarane sapogenins (DS), an active fraction from oriental ginseng, has shown antidepressant-like effects in chronic restraint rats and sleep interruption-induced mice, and the present study aimed to further confirm the antidepressant effects of DS in a model of chronic unpredictable mild stress (CUMS) and to explore the underlying mechanism. Oral administration of DS (20, 40, and 80 mg/kg) markedly improved depressant-like behaviors, increasing the sucrose intake in the sucrose preference test and reducing the latency in the novelty-suppressed feeding test, and decreasing the immobility time in both the tail suspension and forced swimming tests, compared with the CUMS mice. Biochemical analysis of brain tissue and serum showed that DS treatment restored the decreased hippocampal neurotransmitter concentrations of serotonin, dopamine, norepinephrine (noradrenaline), and gamma-aminobutyric acid, and decreased the elevated of serum hormone levels (corticotrophin releasing factor, adrenocorticotrophic hormone, and corticosterone) induced by CUMS. Our findings confirm that DS exerts an antidepressant-like effect in the CUMS model of depression in mice, and suggest it may be mediated by regulation of neurotransmitters and hypothalamic-pituitary-adrenal axis.

20(S)-Protopanaxadiol-Induced Apoptosis in MCF-7 Breast Cancer Cell Line through the Inhibition of PI3K/AKT/mTOR Signaling Pathway

20(S)-Protopanaxadiol (PPD) is one of the major active metabolites of ginseng. It has been reported that 20(S)-PPD shows a broad spectrum of antitumor effects. Our research study aims were to investigate whether apoptosis of human breast cancer MCF-7 cells could be induced by 20(S)-PPD by targeting the Phosphatidylinositol 3-kinase/Protein kinase B/Mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway in vitro and in vivo. Cell cycle analysis was performed by Propidium Iodide (PI) staining. To overexpress and knock down the expression of mTOR, pcDNA3.1-mTOR and mTOR small interfering RNA (siRNA) transient transfection assays were used, respectively. Cell viability and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-test and Annexin V /PI double-staining after transfection. The antitumor effect in vivo was determined by the nude mice xenograft assay. After 24 h of incubation, treatment with 20(S)-PPD could upregulate phosphorylated-Phosphatase and tensin homologue deleted on chromosome 10 (p-PTEN) expression and downregulate PI3K/AKT/mTOR-pathway protein expression. Moreover, G0/G1 cell cycle arrest in MCF-7 cells could be induced by 20(S)-PPD treatment at high concentrations. Furthermore, overexpression or knockdown of mTOR could inhibit or promote the apoptotic effects of 20(S)-PPD. In addition, tumor volumes were partially reduced by 20(S)-PPD at 100 mg/kg in a MCF-7 xenograft model. Immunohistochemical staining indicated a close relationship between the inhibition of tumor growth and the PI3K/AKT/mTOR signal pathway. PI3K/AKT/mTOR pathway-mediated apoptosis may be one of the potential mechanisms of 20(S)-PPD treatment.

Radioprotective effects of dammarane sapogenins against 60 Co-induced myelosuppression in mice

Radiotherapy frequently induces failure of hematopoietic system and leads to myelosuppression. The objective of this study was to investigate the protective effect of dammarane sapogenins (DS), the hydrolysed product of the constituent ginsenosides of Panax ginseng, which are produced by gut metabolism, on radiation-induced hematopoietic injury. Mice were exposed to 3.5 Gy 60 Co γ-rays of total body radiation at a dose rate of 1.60 Gy per minute and treated with DS or granulocyte colony-stimulating factor immediately after radiation. The general condition of the mice, the peripheral blood cell counts, multiple colony forming unit (CFU) assays of hematopoietic progenitor cells, hematopoietic stem cell counts, bone marrow histology, and spleen colony forming unit counts were then investigated. Our results indicated that administration with DS could ameliorate 60 Co-irradiation induced damage and significantly increase the number of peripheral blood cells (white blood cells and platelets), 5 types of hematopoietic progenitor cells CFU (CFU-GM, CFU-E, BFU-E, CFU-Meg, and CFU-GEMM), hematopoietic stem cell (Lin- c-kit+ Scal-1+ ) numbers, and CFUs in the spleen, as well as improved bone marrow histopathology. All together, these results confirmed the enhancement of DS on hematopoiesis.

"Nano-Ginseng" for Enhanced Cytotoxicity AGAINST Cancer Cells

Panax ginseng has high medicinal and health values. However, the various and complex components of ginseng may interact with each other, thus reducing and even reversing therapeutic effects. In this study, we designed and fabricated a novel "nano-ginseng" with definite ingredients, ginsenoside Rb1/protopanaxadiol nanoparticles (Rb1/PPD NPs), completely based on the protopanaxadiol-type extracts. The optimized nano-formulations demonstrated an appropriate size (~110 nm), high drug loading efficiency (~96.8%) and capacity (~27.9 wt %), long half-time in systemic circulation (nine-fold longer than free PPD), better antitumor effects in vitro and in vivo, higher accumulation at the tumor site and reduced damage to normal tissues. Importantly, this process of "nano-ginseng" production is a simple, scalable, green economy process.

Synthesis and neuroprotective effects of the complex nanoparticles of iron and sapogenin isolated from the defatted seeds of Camellia oleifera

CONTEXT

The defatted seeds of Camellia oleifera var. monosperma Hung T. Chang (Theaceae) are currently discarded without effective utilization. However, sapogenin has been isolated and shows antioxidative, anti-inflammatory and analgesic activities suggestive of its neuroprotective function.

OBJECTIVE

In order to improve the activities of sapogenin, the nanoparticles of iron-sapogenin have been synthesized, and the neuroprotective effects are evaluated.

MATERIALS AND METHODS

Structural characters of the nanoparticles were analyzed, and the antioxidant effect was assessed by DPPH method, and the neuroprotective effect was evaluated by rotenone-induced neurodegeneration in Kunming mice injected subcutaneously into the back of neck with rotenone (50 mg/kg/day) for 6 weeks and then treated by tail intravenous injection with the iron-sapogenin at the dose of 25, 50 and 100 mg/kg for 7 days. Mice behaviour and neurotransmitters were tested.

RESULTS

The product had an average size of 162 nm with spherical shape, and scavenged more than 90% DPPH radicals at 0.8 mg/mL concentration. It decreased behavioural disorder and malondialdehyde content in mice brain, and increased superoxide dismutase activity, tyrosine hydroxylase expression, dopamine and acetylcholine levels in brain in dose dependence, and their maximum changes were respectively up to 60.83%, 25.17%, 22.13%, 105.26%, 42.17% and 22.89% as compared to vehicle group. Iron-sapogenin nanoparticle shows significantly better effects than the sapogenin.

DISCUSSION AND CONCLUSION

Iron-sapogenin alleviates neurodegeneration of mice injured by neurotoxicity of rotenone, it is a superior candidate of drugs for neuroprotection.

Synthesis and in vitro anticancer activity of 23(23')E-benzylidenespirostanols derived from steroid sapogenins

Benzylidenespirostanols were prepared by two-step synthesis including BF₃·Et₂O-catalyzed aldol condensation of several acetylated steroid sapogenins with benzaldehyde followed by saponification. The obtained compounds showed moderate cytotoxicity against three cancer cell lines (T-lymphoblastic leukemia cell line CEM, breast carcinoma cell line MCF7 and cervical carcinoma cell line HeLa) and normal human fibroblasts (BJ). The most active of the five tested substances was 3c (lowest IC₅₀ for MCF7 cells 19.9±0.1µM) without any selectivity towards human cancer and normal cells, respectively.

Bupleurum chinense Roots: a Bioactivity-Guided Approach toward Saponin-Type NF-κB Inhibitors

The roots of Bupleurum chinense have a long history in traditional medicine to treat infectious diseases and inflammatory disorders. Two major compounds, saikosaponins A and D, were reported to exert potent anti-inflammatory activity by inhibiting NF-κB. In the present study, we isolated new saikosaponin analogues from the roots of B. chinese interfering with NF-κB activity in vitro. The methanol-soluble fraction of the dichloromethane extract of Radix Bupleuri was subjected to activity-guided isolation yielding 18 compounds, including triterpenoids and polyacetylenes. Their structures were determined by spectroscopic methods as saikogenin D (1), prosaikogenin D (2), saikosaponins B2 (3), W (4), B1 (5), Y (6), D (7), A (8), E (9), B4 (10), B3 (11), and T (12), saikodiyne A (13), D (14), E (15) and F (16), falcarindiol (17), and 1-linoleoyl-sn-glycero-3-phosphorylcholine (18). Among them, 4, 15, and 16 are new compounds, whereas 6, previously described as a semi-synthetic compound, is isolated from a natural source for the first time, and 13-17 are the first reports of polyacetylenes from this plant. Nine saponins/triterpenoids were tested for inhibition of NF-κB signaling in a cell-based NF-κB-dependent luciferase reporter gene model in vitro. Five of them (1, 2, 4, 6, and 8) showed strong (> 50%, at 30 µM) NF-κB inhibition, but also varying degrees of cytotoxicity, with compounds 1 and 4 (showing no significant cytotoxicity) presenting IC50 values of 14.0 µM and 14.1 µM in the cell-based assay, respectively.

Neuroprotective Effects of the Nanoparticles of Zinc Sapogenin from Seeds of Camellia oleifera

The sapogenin isolated from seeds of Camellia oleifera shows central effects in our previous research. Aiming to improve its neuroprotective effects, we synthesize the zinc-sapogenin complex, which has been found with the nanoparticle characters and neuroprotective effects. Its structure is deduced as sapogenin:zinc:water (3:1:1) by ultraviolet spectra, infrared spectra, element analysis, and thermogravimetric analysis. The average size of zinc-sapogenin is 115 nm with plane circular shape by measurement of particle analyzer and scanning electron microscope. The nanoparticle improves DPPH radical scavenging activity due to the enhancement of electron transfer among atoms through the linkage of zinc with the sapogenin. Intraperitoneal injection of zinc-sapogenin reduced mice behavioral disorder and neuron damage induced by neurotoxicity of rotenone, increased antioxidative ability and promoted the neurotransmitters of dopamine and acetylcholine in mice brain. Zinc strengthens stability and effects of the sapogenin, and it is a superior candidate of drugs for neuroprotection without accumulation in brain.

Regulation of bone growth via ligand-specific activation of estrogen receptor alpha

Estrogens are well known for their capacity to promote bone maturation and at high doses to induce growth plate closure and thereby stop further growth. High-dose estrogen treatment has therefore been used to limit growth in extremely tall girls. However, recent data suggest that this treatment may have severe side effects, including increased risk of cancer and reduced fertility. We hypothesized that estrogenic effects in bone are mediated via ERα signaling. Twelve-week-old ovariectomized female C57BL/6 mice were subcutaneously injected for 4 weeks with E2 or selective ERα (PPT) or ERβ (DPN) agonists. After killing, tibia and femur lengths were measured, and growth plate morphology was analyzed. E2- and PPT-treated mice had shorter tibiae and femur bones when compared to vehicle-treated controls, whereas animals treated with DPN had similar bone lengths compared to controls. Growth plate height and hypertrophic zone height were reduced in animals treated with E2 or PPT but not in those treated with DPN, supporting that the effect was mediated via ERα. Moreover, PCNA staining revealed suppressed proliferation of chondrocytes in the tibia growth plate in PPT- or E2-treated mice compared to controls. Our data show that estrogenic effects on bone growth and growth plate maturation are mainly mediated via ERα. Our findings may have direct implications for the development of new and more selective treatment modalities of extreme tall stature using selective estrogen receptor modulators that may have low side effects than high-dose E2 treatment.

[Effect of telomerase activation on biological behaviors of neural stem cells in rats with hypoxic-ischemic insults]

OBJECTIVE

To investigate the effect of telomerase activation on biological behaviors of neural stem cells after hypoxic-ischemic insults.

METHODS

The neural stem cells passaged in vitro were divided into four groups: control, oxygen-glucose deprivation (OGD), OGD+cycloastragenol (CAG) high concentration (final concentration of 25 μM), and OGD+CAG low concentration (final concentration of 10 μM). The latter three groups were subjected to OGD. Telomerase reverse transcriptase (TERT) expression level was evaluated by Western blot. Telomerase activity was detected by telomerase repeat amplification protocol (TRAP). Cell number and neural sphere diameter were measured under a microscope. The activity of lactate dehydrogenase (LDH) was examined by chemiluminescence. Cell proliferation rate and apoptosis were detected by flow cytometry.

RESULTS

After OGD insults, obvious injury of neural stem cells was observed, including less cell number, smaller neural sphere, more dead cells, lower proliferation rate and decreased survival rate. In CAG-treated groups, there were higher TERT expression level and telomerase activity compared with the control group (P<0.05). In comparison with the OGD group, CAG treatment attenuated cell loss (P<0.05) and neural sphere diameter decrease (P<0.05), promoted cell proliferation (P<0.05), and increased cell survival rate (P<0.05). Low and high concentrations of CAG had similar effects on proliferation and survival of neural stem cells (P>0.05). In the normal cultural condition, CAG treatment also enhanced TERT expression (P<0.05) and increased cell numbers (P<0.05) and neural sphere diameter (P<0.05) compared with the control group.

CONCLUSIONS

Telomerase activation can promote the proliferation and improve survival of neural stem cells under the state of hypoxic-ischemic insults, suggesting telomerase activators might be potential agents for the therapy of hypoxic-ischemic brain injury.

[Effect of telomerase activation on biological behaviors of neural stem cells in rats with hypoxic-ischemic insults]

OBJECTIVE

To investigate the effect of telomerase activation on biological behaviors of neural stem cells after hypoxic-ischemic insults.

METHODS

The neural stem cells passaged in vitro were divided into four groups: control, oxygen-glucose deprivation (OGD), OGD+cycloastragenol (CAG) high concentration (final concentration of 25 μM), and OGD+CAG low concentration (final concentration of 10 μM). The latter three groups were subjected to OGD. Telomerase reverse transcriptase (TERT) expression level was evaluated by Western blot. Telomerase activity was detected by telomerase repeat amplification protocol (TRAP). Cell number and neural sphere diameter were measured under a microscope. The activity of lactate dehydrogenase (LDH) was examined by chemiluminescence. Cell proliferation rate and apoptosis were detected by flow cytometry.

RESULTS

After OGD insults, obvious injury of neural stem cells was observed, including less cell number, smaller neural sphere, more dead cells, lower proliferation rate and decreased survival rate. In CAG-treated groups, there were higher TERT expression level and telomerase activity compared with the control group (P<0.05). In comparison with the OGD group, CAG treatment attenuated cell loss (P<0.05) and neural sphere diameter decrease (P<0.05), promoted cell proliferation (P<0.05), and increased cell survival rate (P<0.05). Low and high concentrations of CAG had similar effects on proliferation and survival of neural stem cells (P>0.05). In the normal cultural condition, CAG treatment also enhanced TERT expression (P<0.05) and increased cell numbers (P<0.05) and neural sphere diameter (P<0.05) compared with the control group.

CONCLUSIONS

Telomerase activation can promote the proliferation and improve survival of neural stem cells under the state of hypoxic-ischemic insults, suggesting telomerase activators might be potential agents for the therapy of hypoxic-ischemic brain injury.

Saponins of Agave: Chemistry and bioactivity

The genus Agave comprises more than 400 species with geographical presence in the tropical and sub-tropical regions of the world. These plants have a rich history of folkloric use and are known for a wide spectrum of applications. Secondary metabolites of diverse chemical classes have been reported from Agave species. Owing to their pharmacological significance, the steroidal saponins of Agave have caught the attention of phytochemists, biologists and drug discovery scientists. The present review describes 141 steroidal saponins and sapogenins and covers the literature published from 1970 to 2015. It is a comprehensive and coherent presentation of the structures, methods of chemical profiling, structure elucidation and biological activities of the saponins and sapogenins reported from Agave. The article provides a perspective of the research on steroidal compounds of Agave.

Calcitriol and 20(S)-protopanaxadiol synergistically inhibit growth and induce apoptosis in human prostate cancer cells

The potential cancer preventive roles of calcitriol, the dihydroxylated metabolite of Vitamin D3, as well as 20(S)-protopanaxadiol (aPPD), the aglycone of the protopanaxadiol family of ginsenosides, have gained much attention in recent years for the prevention/treatment of prostate cancer (PCa). In the present study, we evaluated the anticancer and chemosensitization effects of calcitriol at clinically relevant concentrations and aPPD, either alone or in combination, in two well-characterized human PCa cell lines: androgen-sensitive non-metastatic LNCaP cells and androgen-independent metastatic C4-2 cells. The effects of the treatments on PCa cell viability and proliferation rates were evaluated by MTS and Brdu assays, respectively. Combination Indices (CI) and Dose Reduction Indices (DRI) were estimated to assess synergistic anticancer activity using Calcusyn software (Biosoft, Cambridge, UK). Then, we determined the potential Pharmacodynamic interaction mechanisms as follows: The protein expression levels of the genes those are known to control cell cycle (cyclin D1 and cdk2); apoptosis (Bcl-2, Bax, and Capspases 3), androgen receptor and Vitamin D receptors were examined upon combinational treatment. The cell viability assay data show that addition of 10nM calcitriol to aPPD significantly lowered its IC50 values from the range of 41-53μM to 13-23μM, in LNCaP and C4-2 prostate cancer cells. The cell proliferation rate was significantly lower for combination treatments compared to the cells treated with aPPD alone. Similarly, Western blot results indicate that aPPD significantly upregulated Vitamin D receptor (VDR) expression, while calcitriol further enhanced the ability of aPPD to induce pro-apoptotic BAX, increased cleaved caspase-3 and downregulate cdk2 protein levels. Thus, the pharmacodynamic interaction between aPPD and calcitriol in impacting growth inhibition and apoptosis appears to be synergistic in nature. In conclusion, calcitriol sensitizes PCa cells to aPPD-mediated anticancer effects by enhancing its ability to induce apoptosis and reduce cell proliferation, and this synergism may limit calcitriol toxicity by facilitating the use of lower calcitriol doses. The associated increase in VDR expression and calcitriol half-life may be mechanistically associated with this sensitization effect.

Fast Centrifugal Partition Chromatography Fractionation of Concentrated Agave (Agave salmiana) Sap to Obtain Saponins with Apoptotic Effect on Colon Cancer Cells

Separation of potentially bioactive components from foods and plant extracts is one of the main challenges for their study. Centrifugal partition chromatography has been a successful technique for the screening and identification of molecules with bioactive potential, such as steroidal saponins. Agave is a source of steroidal saponins with anticancer potential, though the activity of these compounds in concentrated agave sap has not been yet explored. In this study, fast centrifugal partition chromatography (FCPC) was used coupled with in vitro tests on HT-29 cells as a screening procedure to identify apoptotic saponins from an acetonic extract of concentrated agave sap. The three most bioactive fractions obtained by FCPC at partition coefficients between 0.23 and 0.4 contained steroidal saponins, predominantly magueyoside b. Flow cytometry analysis determined that the fraction rich in kammogenin and manogenin glycosides induced apoptosis, but when gentrogenin and hecogenin glycosides were also found in the fraction, a necrotic effect was observed. In conclusion, this study provides the evidence that steroidal saponins in concentrated agave sap were potential inductors of apoptosis and that it was possible to separate them using fast centrifugal partition chromatography.

Ginsenoside 20(S)-Protopanaxadiol Suppresses Viability of Human Glioblastoma Cells via Down-regulation of Cell Adhesion Proteins and Cell-cycle Arrest

BACKGROUND

Pharmacologically active components of ginseng, particularly protopanaxadiol (PPD)-type ginsenosides, have potent anticancer effects, although their effects on highly malignant glioblastoma multiforme (GBM) have not been systemically evaluated. Identification of effective anticancer ginsenosides and further delineation of their mechanisms of action may provide valuable information that aids in the development of alternative or adjuvant therapy for malignant cancer.

MATERIALS AND METHODS

We examined the viability of human GBM U251-MG and U87-MG cells treated with structurally related PPD-type ginsenosides, including F2, Rh2, compound K (C-K), and PPD.

RESULTS

Incubation with PPD, C-K, and Rh2 significantly reduced the viability of U251-MG and U87-MG cells in a dose- and time-dependent manner. The cytotoxic effect of PPD was accompanied by reduced expression of cell adhesion proteins, including N-cadherin and integrin β1, which led to reduced phosphorylation of focal adhesion kinase. Furthermore, incubation with PPD reduced the expression of cyclin D1 and subsequently induced cell-cycle arrest at the G1 phase.

CONCLUSION

These results collectively indicate that PPD might provide a new strategy for treating malignant GBM, which is quite resistant to conventional anticancer treatment.

Semisynthesis and bioactive evaluation of oxidized products from 20(S)-ginsenoside Rg3, Rh2, protopanaxadiol (PPD) and their 20(R)-epimers as cytotoxic agents

A series of oxidized products have been systematically semisynthesized from 20(S)-ginsenoside Rg3, Rh2, 20(S)-protopanaxadiol (PPD) and their 20(R)-epimers and the majority of these products were evaluated for their cytotoxic activity against HeLa cells and HepG2 cells by MTT assay for the first time. Twenty-two products were obtained and elucidated based on comprehensive (1)H NMR, (13)C NMR, two-dimensional (2D) NMR, and mass spectral data and the results reported in previous literature. All the four ocotillol type saponins (20S,24R(δ86, δ85); 20S,24S(δ87, δ88); 20R,24R(δ86, δ86); 20R,24S(δ86, δ87) were obtained. In addition, eight compounds (3, 8, 9, 10, 15, 16, 19 and 22) with the cyclized side chain were firstly identified. Most of the tested compounds possessed cytotoxicity to a certain degree against the two types of cells which implied these oxidized products could play a certain role on anti-cancer functions of the raw materials in vivo. Meanwhile, the results proved that the configurations at C-20 or C-24 and the number of glycosyl at C-3 have important influence on the cytotoxicity. The products 1, 2, 11-17, 20 and 22 should possess great activities and deserved further investigation as potential cytotoxic agents.

Inhibitory effects of ginseng sapogenins on the proliferation of triple negative breast cancer MDA-MB-231 cells

Because of poor prognosis, clinical treatment of triple-negative (TN) breast cancer remains the most challenging factor in cancer treatment. Extensive research into alternative cancer therapies includes studying the naturopathic effects of the medicinal herb ginseng. This study investigates the anti-neoplastic properties of ginseng sapogenins and the derivatives: (1) (20(S)-protopanaxadiol (PPD), (2) 20(S)-protopanaxatriol), (3) (20(S)-dihydroprotopanaxadiol, and (4) 20(S)-dihydroprotopanaxatriol). These compounds were found to prevent the proliferation of MDA-MB-231 human breast cancer cells. PPD was the most potent inhibitor, exhibiting an IC₅₀ (5.87 μM) comparable to that of the chemotherapeutic drug taxol. Furthermore, PPD induced dose-dependent cleavage of caspase-8, caspase-3, and PARP in MDA-MB-231 cells. Thus, we propose that PPD acts as anti-cancer agent by stimulating caspase-dependent apoptosis in breast cancer cells.