Echinacoside Isolated from Cistanche tubulosa Putatively Stimulates Growth Hormone Secretion via Activation of the Ghrelin Receptor

Molecularly imprinted composite membranes with interleaved imprinted network structure for highly selective separation of acteoside

Acteoside (ACT) is one of the phenylethanoid glycosides in Cistanche tubulosa. The ACT molecules have high medicinal value, but the content of ACT is scarce. Therefore, it is imperative to develop the ACT-based molecularly imprinted composite membranes (A-MICMs) with highly selective separation of ACT. In this study, the amine-polyhedral oligomeric sesquisiloxanes (NH2-POSS) were uniformly introduced into polydopamine modified polyvinylidene fluoride (pDA@PVDF) membranes to fabricate NH2-POSS-pDA@PVDF. Then, the ACT-imprinted layers were synthesized on the surface of NH2-POSS-pDA@PVDF to obtain A-MICMs. The results showed that the optimal conditions were 180 mg DA, 12 h DA self-polymerization time, 400 mg NH2-POSS and 10 h washing time for the synthesis of A-MICMs. The results of adsorption isotherm experiments showed that there was a single layer adsorbate analyte on the A-MICMs. The results of adsorption kinetic experiments showed that chemisorption mechanism played a major function in the adsorption process of A-MICMs for ACT. The A-MICMs exhibited the maximum rebinding capacity of 98.37 mg⋅g-1, an excellent rebinding selectivity of 4.63, and the permselectivity of 7.02. The same A-MICMs kept 95.99% of the maximum rebinding capacity for ACT after 5 adsorption-desorption cycles. The designed A-MICMs with the interleaved imprinted network structure have a potential to be applied to the highly selective separation of bioactive components from natural products.

Establishment of a Cell Line Stably Expressing the Growth Hormone Secretagogue Receptor to Identify Crocin as a Ghrelin Agonist

The growth hormone secretagogue receptor-1a (GHSR1a) is the endogenous receptor for ghrelin. Activation of GHSR1a participates in many physiological processes including energy homeostasis and eating behavior. Due to its transitory half-life, the efficacy of ghrelin treatment in patients is restricted; hence the development of new adjuvant therapy is an urgent need. This study aimed to establish a cell line stably expressing GHSR1a, which could be employed to screen potential ghrelin agonists from natural compounds. First, by means of lentiviral transduction, the genome of a human HEK293T cell was modified, and a cell platform stably overexpressing GHSR1a was successfully established. In this platform, GHSR1a was expressed as a fusion protein tagged with mCherry, which allowed the monitoring of the dynamic cellular distribution of GHSR1a by fluorescent microscopy. Subsequently, the authenticity of the GHSR1a mediated signaling was further characterized by using ghrelin and teaghrelin, two molecules known to stimulate GHSR1a. The results indicated that both ghrelin and teaghrelin readily activated GHSR1a mediated signaling pathways, presumably via increasing phosphorylation levels of ERK. The specific GHSR1a signaling was further validated by using SP-analog, an antagonist of GHSR1a as well as using a cell model with the knockdown expression of GHSR1a. Molecular modeling predicted that crocin might be a potential ghrelin agonist, and this prediction was further confirmed by the established platform.

Analysis of microbial diversity and community structure of rhizosphere soil of Cistanche salsa from different host plants

Host plants influence rhizosphere microorganism composition through root secretions, and rhizosphere associated microorganisms influence Cistanche seeds germination. At present, little is known about effects of different host plants on soil bacteria and fungi in the rhizosphere of Cistanche salsa. High-throughput sequencing was used here to reveal the similarities and differences in the structural composition of the soil microbial community of C. salsa from six host plants (i.e., Halocnemum strobilaceum, Atriplex patens, Kalidium foliatum, Caroxylon passerinum, Anabasis aphylla, Krascheninnikovia ceratoides). We discovered that Krascheninnikovia ceratoides-parasitizing C. salsa (YRCR6) had the highest diversity of rhizosphere bacterial communities, and Anabasis aphylla -parasitizing C. salsa (YRCR5) had the highest diversity of rhizosphere fungal communities. Fungal communities were more influenced by the host plant than bacterial communities. In addition, we discovered certain rhizosphere microorganisms that may be associated with Cistanche seeds germination, including Mortierella, Aspergillus alliaceus, and Cladosporium, which are account for a relatively high proportion in Halocnemum strobilaceum, Atriplex patens and Anabasis aphylla -parasitizing C. salsa. Redundancy analysis results also revealed that AP, HCO₃^–, pH, Ca²⁺, SO₄^2–, and K⁺ had a highly significant impact on the bacterial community structure (P < 0.01), while pH and SO₄^2– had a significant impact on the fungal community structure (P < 0.05). Conclusively, differences were noted in the structure of rhizosphere bacterial and fungal communities of C. salsa parasitizing different plants in the same habit and the difference may be related to the host plant. This result can provide a new ideas for the selection of host plants and the cultivation of C. salsa.

Echinacoside Inhibits Osteoclast Function by Down-Regulating PI3K/Akt/C-Fos to Alleviate Osteolysis Caused by Periprosthetic Joint Infection

Infected osteolysis as a common secondary osteoporosis is associated with excessive osteoclastogenesis and bone resorption. The inhibition of osteoclastogenesis and bone resorption have been demonstrated an effective approach in the treatment of osteolytic diseases. Echinacoside (ECH) is a natural phenylethanoid glycoside with multiple biological functions, including anti-inflammatory, antioxidant, and osteoblast differentiation promotion. However, the effects of ECH on osteoclast differentiation and bone resorption function remain unknown. In vitro, we investigated the effects of ECH on osteoclast differentiation and bone resorption induced by RANKL and its potential mechanisms. In vivo, we established a periprosthetic joint infection (PJI) rat model and demonstrated the changes of infected osteolysis and osteoclasts activities in surgical sites. ECH (20 mg/kg) was injected intraperitoneally after debridement for 4 weeks. Radiological evaluation and bone histomorphometric analysis was performed to assess the efficacy of ECH. The results showed that ECH inhibited osteoclast differentiation, F-actin belts formation, bone resorption function and osteoclast-specific gene expression by preventing NFATc1 translocation, down-regulating its expression and affecting the PI3K/Akt/c-Fos pathway in vitro. ECH also alleviated in vivo PJI-induced osteolysis and maintained bone mass by inhibiting osteoclast activity. Our study indicated that ECH attenuated RANKL-induced osteoclastogenesis and PJI-induced bone loss and was shown as a potentially effective therapeutic agent for osteoclast-related bone diseases.

Anti-Inflammatory Principles from the Needles of Pinus taiwanensis Hayata and In Silico Studies of Their Potential Anti-Aging Effects

Pinus needle tea are very popular in Eastern countries such as Japan, Russia, Korea, and China. Pine needle tea is claimed to have significant anti-aging effects, but no clear evidence has supported this until now. In the present study, five undescribed compounds (1–5) as well as seventy-two known compounds were purified and characterized from the bioactive fraction of methanol extracts of P. taiwanensis needles. Most of the isolates were examined for their anti-inflammatory bioactivity by cellular neutrophil model and six compounds (45, 47, 48, 49, 50, and 51) exhibited a significant inhibition on superoxide anion generation and elastase release with IC₅₀ values ranging from 3.3 ± 0.9 to 8.3 ± 0.8 μM. These anti-inflammatory ingredients were subjected to docking computing to evaluate their binding affinity on the ghrelin receptor, which played an important role in regulating metabolism, with anti-aging effects. Compounds 49, 50, and 51 formed a stable complex with the ghrelin receptor via hydrogen bonds and different types of interactions. These results suggest the flavonoids are responsible for the potential anti-aging effects of pine needle tea.

PERK Pathway and Neurodegenerative Disease: To Inhibit or to Activate?

With the extension of life span in recent decades, there is an increasing burden of late-onset neurodegenerative diseases, for which effective treatments are lacking. Neurodegenerative diseases include the widespread Alzheimer’s disease (AD) and Parkinson’s disease (PD), the less frequent Huntington’s disease (HD) and Amyotrophic Lateral Sclerosis (ALS) and also rare early-onset diseases linked to mutations that cause protein aggregation or loss of function in genes that maintain protein homeostasis. The difficulties in applying gene therapy approaches to tackle these diseases is drawing increasing attention to strategies that aim to inhibit cellular toxicity and restore homeostasis by intervening in cellular pathways. These include the unfolded protein response (UPR), activated in response to endoplasmic reticulum (ER) stress, a cellular affliction that is shared by these diseases. Special focus is turned to the PKR-like ER kinase (PERK) pathway of the UPR as a target for intervention. However, the complexity of the pathway and its ability to promote cell survival or death, depending on ER stress resolution, has led to some confusion in conflicting studies. Both inhibition and activation of the PERK pathway have been reported to be beneficial in disease models, although there are also some reports where they are counterproductive. Although with the current knowledge a definitive answer cannot be given on whether it is better to activate or to inhibit the pathway, the most encouraging strategies appear to rely on boosting some steps without compromising downstream recovery.

Role of pyroptosis in spinal cord injury and its therapeutic implications

BACKGROUND

Currently, spinal cord injury (SCI) is a pathological incident that triggers several neuropathological conditions, leading to the initiation of neuronal damage with several pro-inflammatory mediators' release. However, pyroptosis is recognized as a new programmed cell death mechanism regulated by the stimulation of caspase-1 and/or caspase-11/-4/-5 signaling pathways with a series of inflammatory responses.

AIM

Our current review concisely summarizes the potential role of pyroptosis-regulated programmed cell death in SCI, according to several molecular and pathophysiological mechanisms. This review also highlights the targeting of pyroptosis signaling pathways and inflammasome components and its therapeutic implications for the treatment of SCI.

KEY SCIENTIFIC CONCEPTS

Multiple pieces of evidence have illustrated that pyroptosis plays significant roles in cell swelling, plasma membrane lysis, chromatin fragmentation and intracellular pro-inflammatory factors including IL-18 and IL-1β release. In addition, pyroptosis is directly mediated by the recently discovered family of pore-forming protein known as GSDMD. Current investigations have documented that pyroptosis-regulated cell death plays a critical role in the pathogenesis of multiple neurological disorders as well as SCI. Our narrative article suggests that inhibiting the pyroptosis-regulated cell death and inflammasome components could be a promising therapeutic approach for the treatment of SCI in the near future.

Design and Preparation of Molecularly Imprinted Membranes for Selective Separation of Acteoside

Acteoside (ACT) belongs to a type of phenylethanoid glycosides (PhGs), and it is worthy of obtaining high-purity due to its significant medicinal functions. In this study, a novel class of MIMs was designed and synthesized with PVDF membranes as the base membrane for high selective separation and enrichment of ACT. The effects of the different functional monomers, the amounts of functional monomers, crosslinking agents, and initiators on the separation properties of MIMs were investigated. Furthermore, adsorption ability, permeation capacity, and reusability of MIMs were discussed for ACT. It indicated that MIM7 was the optimal performance of MIMs. The adsorption ability of MIM7 for ACT was 62.83 mg/g, and the selectivity factor (α) of MIM7 was up to 2.74 and its permeability factor (β) was greater than 2.66. Moreover, the adsorption amount of MIM7 was still more than 88.57% of the initial value after five cycles. As an ACT imprinted layer of MIMs only had recognition sites for ACT molecules, which recombined with the recognition sites in the membrane permeation experiment, ACT molecules penetration was hindered. However, the analogs of ECH successfully passed MIMs. It indicated that the selective MIMs for ACT followed the mechanism of delayed permeation. This work provides an important reference for the high permselective separation of natural products.

Quercetin 3-O-malonylglucoside in the leaves of mulberry (Morus alba) is a functional analog of ghrelin

Mulberry (Morus alba) leaf is traditionally consumed as a functional tea with remedial effects, such as preventing aging-related diseases. Two similar compounds, quercetin 3-O-malonylglucoside, and kaempferol 3-O-malonylglucoside, were detected in mulberry leaves and found to be structural recombinant composites of teaghrelin and emoghrelin, two classes of non-peptidyl compounds functionally identified as analogs of ghrelin. Molecular modeling showed that these two mulberry compounds were able to enter and interact with the ghrelin receptor and theoretical calculation revealed that they were similar to emoghrelin but slightly weaker than teaghrelin in terms of interaction with the receptor. The relatively abundant compound, quercetin 3-O-malonylglucoside was subjected to a bioactivity assay, and the result confirmed that it was able to increase the growth hormone secretion of rat anterior pituitary cells. It seems that quercetin 3-O-malonylglucoside is also a functional analog of ghrelin and presumably a key ingredient for the anti-aging activity of mulberry leaves. PRACTICAL APPLICATIONS: According to this study, quercetin 3-O-malonylglucoside and kaempferol 3-O-malonylglucoside are suggested to serve as active ingredients in tea products prepared from mulberry leaves. Contents of these two compounds might be used as key factors for breeding or screening mulberry varieties for commercial cultivation. Moreover, water extract of mulberry leaves containing these compounds can be used as an adequate supplement for functional food.

Phytochemical parasite-host relations and interactions: A Cistanche armena case study

The holoparasitic genus Cistanche (Orobanchaceae) has been the most widely used and well known genus in traditional Chinese medicine for centuries. This is the first study that reports the phytochemical profile of Cistanche armena - an endemic species from Armenia and evaluates the composition and biological activity in relation to specific organs of the parasite (flowers vs stem with tuber) and its interaction with two host species: Alhagi maurorum (Fabaceae) and Salsola dendroides (Chenopodiaceae). We identified polyphenolic compounds using the UPLC-PDA-MS/MS method and quantified the antioxidative effects; inhibitory activities; polyphenol, nitrate III and nitrate V contents; ABTS+, DPPH, and FRAP activities; and colour parameters. A total of 28 polyphenolic compounds were tentatively identified. In C. armena, 9 compounds belonged to the phenylethanoid glycosides, mainly acteoside, B-hydroxyverbascoside and echinacoside, and in its hosts, 19 compounds belonged mainly to hydroxycinnamic acid and the flavanols. The profile of polyphenols in the host species was qualitatively and quantitatively different than the profile of the compounds in the parasite; this indicates the existence of a unique pathway of compound biosynthesis in the parasite. The colour and the amount and bioactivity of the polyphenolic compounds found in Cistanche were very diverse and depended on both the host plant and their location (organs) in the parasite. The stem and tuber of Cistanche hosted by Salsola had the highest polyphenol content, which was approximately 4 times higher than that in the stem and flowers of Cistanche individuals that parasitized A. maurorum. In addition, the stem and tuber of Cistanche that parasitized S. dendroides was characterized by the highest antioxidant activity (ABTS+, DPPH and FRAP) and high inhibitory activities. Conversely, the amount of polyphenols in the host Alhagi was 12 times higher than that in S. dendroides. These results highlight the importance of C. armena as a promising source of functional and bioactive ingredients (harvested from potential cultivation, not from natural endangered localities) and also draws the attention of future researchers to an important aspect regarding the parasite organ and the host's influence on the harvested material of various parasitic herbs.

Selective Adsorption and Purification of the Acteoside in Cistanche tubulosa by Molecularly Imprinted Polymers

Acteoside (ACT) is the main component of phenylethanoid glycosides in Cistanche tubulosa, and it is extremely desirable for obtaining high purification of ACT by molecularly imprinted polymers (MIPs) from their extracts. In this study, MIPs were designed and synthetized to adsorb selectively the ACT in C. tubulosa. The effects of different functional monomers, cross-linkers, and solvents of MIPs were investigated. MIPs were studied in terms of static adsorption experiments, dynamic adsorption experiments, and selectivity experiments. The optimal functional monomer, cross-linking agent, and solvent are 4-vinylpyridine, ethylene glycol dimethylacrylate, and the mixed solvent (acetonitrile and N,N-dimethylformamide, 1:1.5, v/v), respectively. Under the optimal conditions, the synthesized MIP1 has a high adsorption performance for ACT. The adsorption capacity of MIP1 to ACT reached 112.60 mg/g, and the separation factor of ACT/echinacoside was 4.68. Because the molecularly imprinted cavities of MIP1 resulted from template molecules of ACT, it enables MIP1 to recognize selectively ACT. Moreover, the N–H groups on MIP1 can form hydrogen bonds with the hydroxyl groups on the ACT; this improves the separation factor of MIP1. The dynamic adsorption of ACT accorded with the quasi-second-order kinetics; it indicated that the adsorption process of MIP1 is the process of chemical adsorption to ACT. MIPs can be applied as a potential adsorption material to purify the active ingredients of herbal medicines.

Highly Efficient Adsorption of Phenylethanoid Glycosides on Mesoporous Carbon

PhGs are the major active compounds of Cistanche tubulosa, and it is extremely desirable for obtaining high purification of PhGs by adsorption from their extracts. To explore highly efficient adsorption of PhGs, a novel adsorption material for the efficient separation and purification of phenylethanoid glycosides (PhGs) from Cistanche tubulosa was explored. The three mesoporous carbons of ordered mesoporous carbon (CMK-3), disordered mesoporous carbon (DMC), and three-dimensional cubic mesoporous carbon (CMK-8) were compared for adsorption of PhGs. Meanwhile, adsorption isotherms, adsorption kinetics, and the optimization of adsorption conditions were investigated. The results indicated that CMK-3 showed the highest adsorption capacity of 358.09 ± 4.13 mg/g due to its high specific surface area, large pore volume and oxygen-containing functional groups. The experimental data can be accurately described using the Langmuir model and pseudo-second-order model. The intra-particle diffusion model suggested that the rate-limiting steps of adsorption were intra-particle diffusion.