Preparative purification of salidroside from Rhodiola rosea by two-step adsorption chromatography on resins

A review of the polyphenols purification from apple products

Apple polyphenols are one of the major bioactive compounds in apple products and have strong anti-inflammatory effects and the ability to prevent chronic diseases with health benefits. The development of apple polyphenol products is dependent on the extraction, purification and identification of apple polyphenols. The extracted polyphenols need to be further purified to improve the concentration of the extracted polyphenols. This review, therefore, presents the studies on the conventional and novel methods for polyphenols purification from apple products. The different chromatography methods, as one of the most widely used conventional purification methods, for polyphenol purification from various apple products are introduced. In addition, the perspective of the adsorption-desorption process and membrane filtration technique in enhancing the purification of polyphenols from apple products are presented in this review. The advantages and disadvantages of these purification techniques are also discussed and compared in depth. However, each of the reviewed technologies has some disadvantages that need to be overcome, and some mechanisms need to be further identified. Therefore, more competitive polyphenols purification techniques need to emerge in the future. It is hoped that this review can provide a research basis for the efficient purification of apple polyphenols, which can facilitate their application in various fields.

Rosavin exerts an antitumor role and inactivates the MAPK/ERK pathway in small-cell lung carcinoma in vitro

This study attempts to explore the function and mechanism of action of rosavin in small-cell lung cancer (SCLC) in vitro. The viability and clone formation of SCLC cells were assessed using cell counting kit-8 and colony formation assays, respectively. Apoptosis and cell cycle were detected using flow cytometry and cell cycle analysis, respectively. Wound healing and transwell assays were performed to evaluate the migration and invasion of SCLC cells. Besides, protein levels of p-ERK, ERK, p-MEK and MEK were determined using Western blot analysis. Rosavin repressed the viability and clone formation of SCLC cells, and promoted apoptosis and G₀/G₁ arrest of SCLC cells. At the same time, rosavin suppressed migration and invasion of SCLC cells. Moreover, protein levels of p-ERK/ERK and p-MEK/MEK were decreased after rosavin addition in SCLC cells. Rosavin impaired malignant behaviors of SCLC cells, which may be associated with inhibition of the MAPK/ERK pathway in vitro.

A facile macroporous resin-based method for separation of yellow and orange Monascus pigments

The yellow Monascus pigments (YMPs) named monascin and ankaflavin and the orange Monascus pigments (OMPs) named rubropunctatin and monascorubrin are two groups of bioactive components in a mixture state in the Monascus fermented products. In order to separate these two groups of bioactive pigments, a facile macroporous resin-based method was developed. The weak-polar resin CAD-40 was selected from the seven tested macroporous resins as it revealed better properties for the adsorption and desorption of the YMPs and OMPs. Then, CAD-40 resin was used for column-chromatographic separation. After eluted by 4 bed volumes of ethanol, the yellow group (monascin and ankaflavin) and the orange group (rubropunctatin and monascorubrin) were successfully separated and purified, with an increased content from 49.3% and 44.2% in the crude pigment extract to 85.2% and 83.0% in the final products, respectively. This method would be helpful for the large-scale separation and purification of Monascus pigment products with specific bioactivity.

Protective effects of Rosavin on bleomycin-induced pulmonary fibrosis via suppressing fibrotic and inflammatory signaling pathways in mice

Idiopathic Pulmonary fibrosis (IPF) is diagnosed as a life-threatening, progressive and incurable lung disease characterized by accumulation of extracellular matrix and myofibroblasts, resulting in the function degradation and structural alterations in normal lung parenchyma. Notably, Pulmonary Fibrosis has been considering as a difficult problem in clinical with high mortality and effective treatment strategies. Rosavin, a benzylPropylene glycoside, is isolated from Rhodiola rosea L., exhibiting nootropic, anti-depressant, anti-cancer, anti-inflammatory and anti-oxidative activities. In this study, we attended to elucidate the pharmacological activity of Rosavin for treatment of pulmonary fibrosis induced by bleomycin in mice. The results indicated that Rosavin could significantly ameliorate the lung index and Pathological structure of mice with Pulmonary fibrosis by bleomycin-induced. Additionally, Rosavin could evidently decreased inflammatory cells infiltration in bronchoalveolar lavage fluid and pro-inflammatory cytokines expression in lung tissue specimens induced by bleomycin. Rosavin could down-regulate the expression of hydroxyproline and malondialdehyde and increased the activities of superoxide dismutase, glutathione peroxidase in lung tissue. The expression of Nrf2 were increased, and the expression of NF-κB p65, TGF-β1 and α-SMA were inhibited. The findings revealed the protective effects and the primary mechanism of rosavin on bleomycin-induced pulmonary fibrosis, which provided a scientific foundation for Rosavin as a promising candidate for Pulmonary fibrosis treatment.

Effect of ion form of the ion-exchange resin on ε-poly-l-lysine purification from microbial fermentation broth

ε-Poly-l-lysine (ε-PL) is an added-value natural product with widespread application in the fields of food, pharmaceuticals and biopolymer materials. However, the high production cost reduces its application. To improve the efficiency of ε-PL purification for decreasing the cost of downstream processes, the ion form of the ion-exchange resin, which is widely used for ε-PL purification, was investigated systematically in this study. Among eleven cation-exchange resins tested, the Amberlite IRC-50 resin offered the best adsorption capability and the highest desorption ratio. The adsorption kinetics of IRC-50 resin with H⁺, Na⁺ and NH₄ ⁺ ion forms followed a pseudo-second-order model. The dynamic adsorption and desorption parameters of ε-PL were optimized with a column packed with IRC-50 resin with Na⁺ and NH₄ ⁺. It is suggested that NH₄ ⁺ is the optimal ion form of IRC-50 resin for ε-PL extraction. Under optimal conditions, the IRC-50 resin with NH₄ ⁺ achieved the highest ε-PL adsorption capability, purity and recovery ratio of 307.96 mg g^-1, 76.52% and 96.2%, respectively. After further purification, a final ε-PL purity of 97.10% was achieved with a total recovery ratio of 66.01%. This is the first report on improving the ε-PL purification efficiency through optimizing the ion form of the ion-exchange resin. Moreover, it would offer guidance for other natural product recovery processes by ion-exchange chromatography.

Purification of 3, 4-dihydroxyphenylethyl alcohol glycoside from Sargentodoxa cuneata (Oliv.) Rehd. et Wils. and its protective effects against DSS-induced colitis

Sargentodoxa cuneata is a tropical plant used in traditional Chinese medicine to treat intestinal inflammation. In this study, 3, 4-dihydroxyphenylethyl alcohol glycoside (DAG) was purified from the stem of S. cuneata using macroporous resins and its bioactivity was also investigated. The adsorption/desorption of DAG on macroporous resins was investigated systematically. HPD300 resin was selected as the most suitable medium for DAG purification. Further dynamic absorption/desorption experiments on the HPD300 column were conducted to obtain the optimal parameters. To obtain more than 95% DAG, a second stage procedure was developed to purify the DAG using SiliaSphere C18 with 8% v/v acetonitrile through elution at low pressure. Further investigation showed that DAG pretreatment significantly reversed the shortening of colon length, the increase in the disease activity index (DAI) scores and histological damage in the colon. Moreover, DAG greatly increased SOD and GPx activities, significantly decreased MPO and MDA activities and reduced the levels of pro-inflammatory cytokines in the colon. Free radical scavenging activities of DAG were assessed using DPPH, with an IC50 value of 17.03 ug/mL. Additionally, DAG suppressed ROS and proinflammatory cytokine production in LPS-stimulated RAW 264.7 macrophages by suppressing activation of the ERK1/2 and NF-κB pathways. The results were indicative of the antioxidant and anti-inflammatory properties of DAG. When viewed together, these findings indicated that DAG can be used to expand future pharmacological research and to potentially treat colitis.

An effective method based on medium-pressure liquid chromatography and recycling high-speed counter-current chromatography for enrichment and separation of three minor components with similar polarity from Dracocephalum tanguticum

The separation of minor compounds, especially those with similar polarities from a complex sample, remains challenging. In the proposed study, an effective method based on medium-pressure liquid chromatography and recycling high-speed counter-current chromatography was developed for the enrichment and separation of three minor components from Dracocephalum tanguticum. The crude extract was directly introduced to medium-pressure liquid chromatography for the enrichment of the three minor components. Based on high-performance liquid chromatography analysis, the total content of these three compounds increased from 0.48% in the crude extract to 85.3% in the medium-pressure liquid chromatography fraction. In addition, high-speed counter-current chromatography was employed to separate the enriched compounds using the solvent system hexane/ethyl acetate/methanol/water (1.18:8.82:1.18:8.82, v/v/v/v). As a result, compound 3 and a mixture of compounds 1 and 2 were obtained. In order to improve the resolution of compounds 1 and 2 while saving separation time, a recycling and heart-cut mode was used. Finally, compounds 1 and 2 were obtained after five cycles. These compounds were identified as 3-phenylethyl β-d-glucopyranoside (1), tazettoside E (2), and cirsiliol-4'-glucoside (3). Compounds 1 and 2 were primarily separated from D. tanguticum. Moreover, the developed method provided a reference for the separation of minor components from the complex sample.

Simultaneous Preparation of Salidroside and p-Tyrosol from Rhodiola crenulata by DIAION HP-20 Macroporous Resin Chromatography Combined with Silica Gel Chromatography

The Rhodiola species have a long history of utilization in traditional medicine and have been considered as a source of adaptation to environmental challenges; salidroside and p-tyrosol are the major responsible compounds. Here we propose a novel UPLC-guided two-step method consisting of a DIAION HP-20 adsorption and silica gel column chromatographies, which can simultaneously prepare high purities of salidroside and p-tyrosol with noticeable yields from the rhizome of Rhodiola crenulata. Results demonstrated that DIAION HP-20 could successfully remove all impurities except crenulatin during a gradient elution with 5–20% ethanol, which could achieve an optimal purification of salidroside and p-tyrosol with increasing rates of 29.19% and 33.44%, respectively. Furthermore, chloroform was selected as an ideal solvent for separating p-tyrosol with salidroside, and thus crenulatin was subsequently applied in the silica gel chromatography, and the separation of salidroside with crenulatin could be achieved using silica gel chromatography with a mixture of chloroform and methanol at a volume ratio of 4:1. High purity rates of 94.17% and 97.29% and overall yields of 39.09% and 43.73% for salidroside and p-tyrosol were simultaneously achieved. Our method provides a new way to simultaneously obtain salidroside and p-tyrosol from R. Crenulata, as well as other related plant species.

Salidroside improves brain ischemic injury by activating PI3K/Akt pathway and reduces complications induced by delayed tPA treatment

Cerebral ischemia causes blood-brain barrier (BBB) injury and thus increases the risk of complications secondary to thrombolysis, which limited its clinical application. This study aims to clarify the role and mechanism of salidroside (SALD) in alleviating brain ischemic injury and whether pretreatment of it could improve prognosis of delayed treatment of tissue plasminogen activator (t-PA). Rats were subjected to 3 h of middle cerebral artery occlusion (MCAO) and were intraperitoneally administered with 10, 20 or 40 mg/kg SALD before ischemia. 1.5% 5-triphenyl-2H-tetrazolium chloride (TTC) staining and neurological studies were performed to observe the effectiveness of SALD. The expressions and the distribution of phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) signaling were analyzed. Experiments were further conducted in isolated microvessels and human brain microvascular endothelial cells (HBMECs) to explore the protective mechanism of SALD. Finally, rats were subjected to 6 h of MCAO and 24 h of reperfusion. tPA was given with or without the pretreatment of SALD. Various approaches including gelatin zymography, western blot and immunofluorescence were used to evaluate the effect of this combination therapy. SALD could reduce cerebral ischemic injury and enhance HBMECs viability subjected to OGD. In vivo and in vitro studies showed the mechanism might be related to the activation of PI3K/Akt signaling by phosphorylating Akt on Ser473. Pretreatment of SALD could alleviate BBB injury and improve the outcome of delayed treatment of tPA. These results provide evidence that SALD might be an effective adjuvant to reduce the complications induced by delayed tPA treatment for brain ischemia.

Enrichment and Purification of Polyphenol Extract from Sphallerocarpus gracilis Stems and Leaves and in Vitro Evaluation of DNA Damage-Protective Activity and Inhibitory Effects of α-Amylase and α-Glucosidase

An efficient preparative separation method for Sphallerocarpus gracilis stems and leaves polyphenols (SGslP) was established in this study. An X-5 macroporous adsorption resin was selected for the purification of the SGslP, and the polyphenol content of the purified SGslP (PSGslP) was increased 5.11-fold from 8.29% to 42.38% after one treatment run. The chemical composition of the PSGslP was analyzed by HPLC-MS/MS, and the predominant compounds were found to be luteolin-7-glucoside, acacetin-7-acetyglycoside and its isomers. In addition, the PSGslP was evaluated in vitro to determine the DNA damage-protective activity and inhibitory effects of α-amylase and α-glucosidase. The results indicated that the PSGslP exhibited significant protective activities against both ROO• and •OH radical-induced DNA damage. Moreover, the PSGslP exerted a dose-dependent inhibition effect on α-glucosidase but no inhibitory effect on α-amylase. These findings indicate that the Sphallerocarpus gracilis stems and leaves are good natural sources of antioxidants and are potent inhibitors of α-glucosidase activity and are potential anti-diabetic inhibitor.

Separation and purification of epigallocatechin-3-gallate (EGCG) from green tea using combined macroporous resin and polyamide column chromatography

Epigallocatechin-3-gallate (EGCG) is a major bioactive ingredient of green tea that produces beneficial neuroprotective effects. In this paper, to optimize the EGCG enrichment, thirteen macroporous resins with different chemical and physical properties were systemically evaluated. Among the thirteen tested resins, the H-bond resin HPD826 exhibited best adsorption/desorption capabilities and desorption ratio, as well as weakest affinity for caffeine. The absorption of EGCG on the HPD826 resin followed the pseudo-second-order kinetics and Langmuir isotherm model. The separation parameters of EGCG were optimized by dynamic adsorption/desorption experiments with the HPD826 resin column. Under the optimal condition, the content of EGCG in the 30% ethanol eluent increased by 5.8-fold from 7.7% to 44.6%, with the recovery yield of 72.1%. After further purification on a polyamide column, EGCG with 74.8% purity was obtained in the 40-50% ethanol fraction with a recovery rate of 88.4%. In addition, EGCG with 95.1% purity could be easily obtained after one-step crystallization in distilled water. Our study suggests that the combined macroporous resin and polyamide column chromatography is a simple method for large-scale separation and purification of EGCG from natural plants for food and pharmaceutical applications.

Preparative Purification of Liriodendrin from Sargentodoxa cuneata by Macroporous Resin

The preparative purification of liriodendrin from Sargentodoxa cuneata using macroporous resin combined with crystallization process was evaluated. The properties of adsorption/desorption of liriodendrin on eight macroporous resins were investigated systematically. X-5 resin was selected as the most suitable medium for liriodendrin purification. The adsorption of liriodendrin on X-5 resin fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. Dynamic adsorption/desorption tests were performed using a glass column packed with X-5 resin to optimize the separation process of liriodendrin. After one treatment with X-5 resin, the content of liriodendrin in the product was increased 48.73-fold, from 0.85% to 41.42%, with a recovery yield of 88.9%. 97.48% liriodendrin was obtained by further crystallization and determined by HPLC. The purified product possessed strong antioxidant activity. In conclusion, purification of liriodendrin might expend its further pharmacological researches and further applications in pharmacy.

An UPLC-MS-based metabolomics investigation on the anti-fatigue effect of salidroside in mice

An ultra-performance liquid chromatography-quadrupole time-of-flight-based metabolomic approach was developed to study influence of salidroside, an anti-fatigue ingredient from Rhoiola rosea, on urinary metabolic profiling of rats to a single dose of 180 mg/kg per day. Unsupervised principal component analysis (PCA) and supervised orthogonal pre-projection to latent structures discriminate analysis (OPLS-DA) on metabolite profiling revealed obvious differentiation between the salidroside treated groups and controls in both positive and negative ion modes. Eleven urinary metabolites contributing to the differentiation were identified as anti-fatigue biomarkers: N-acetylserotonin, 2-Methoxyestrone 3-glucuronide, Taurine, Melatonin, Sorbitol, Geranyl diphosphate, Z-nucleotide, Cortisone, Dihydrocortisol, Sebacic acid, Pregnenolone sulfate. The physiological significance of these biomarkers is discussed. The work showed that metabolomics is a powerful tool in studying the anti-fatigue effects of natural compound salidroside on multiple targets in vivo.

Ultrasound-assisted extraction and preliminary purification of proanthocyanidins and chlorogenic acid from almond (Prunus dulcis) skin

An aqueous solution of polyethylene glycol (PEG) as a green solvent was employed for the first time to develop the ultrasound-assisted extraction of proanthocyanidins (PA) and chlorogenic acid (CA) from almond skin. The optimized extraction parameters were determined based on response surface methodology, and corresponded to an ultrasound power of 120 W, a liquid-to-solid ratio of 20:1 (mL/g), and a PEG concentration of 50% (v/v). Under these optimized conditions, the extraction yields of PAs and CA from almond skin were 32.68 ± 0.22 and 16.01 ± 0.19 mg/g, respectively. Compared with organic solvent extraction, PEG solution extraction produced higher yields. Different macroporous resins were compared for their performance in purifying PAs and CA from almond skin extract. Static adsorption/desorption experimental results demonstrated that AB-8 resin exhibits excellent purification performance at pH 4. Under the optimized dynamic adsorption/desorption conditions on the AB-8 column, the total recovery of purification for PAs and CA was 80.67%. The total content of PAs and CA in the preliminarily purified extract was 89.17% (with respective contents of 60.90 and 28.27%).

Separation and purification of flavonoid from Taxus remainder extracts free of taxoids using polystyrene and polyamide resin

An efficient separation process of flavonoid from Taxus wallichiana var. mairei remainder extracts free of taxoids was developed in this study. AB-8 macroporous resin and polyamide resin offered the fine adsorption capacity, and its adsorption rate at 30°C fitted well to the Langmuir and Freundich isotherms. Resin dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from T. wallichiana var. mairei remainder extracts free of taxoids. The optimum parameters for adsorption by AB-8 resin were as follows: (1) the concentration of flavonoids in a sample solution of 5.61 mg/mL with a processing volume of 2 bed volume (BV) (60 mL); (2) for desorption, ethanol-water (80:20, v/v), with 6 BV as an eluent at a flow rate of 2 BV/h. After a one-run treatment with AB-8 resin, the content of flavonoids was increased 5.10-fold from 4.05 to 20.65%. The optimum parameters for adsorption by polyamide resin were as follows: processing volume of 2 BV (30 mL); for desorption, ethanol-water (70:30, v/v), with 8 BV as an eluent at a flow rate of 2 BV/h. After one-run treatment with polyamide resin, the content of total flavonoids increased from 20.65 to 65.21%. The method will provide a potential approach for large-scale separation and purification of flavonoid for its wide pharmaceutical use.

Adsorption features of flavonoids on macroporous adsorption resins functionalized with ionic liquids

A series of macroporous adsorption resins (MARs) with novel structures is synthesized via Friedel-Crafts catalyzed reaction. The adsorption kinetics of the synthetic resins with respect to the purification effect is systematically investigated by means of the response surface methodology (RSM). The kinetic data cannot be fitted to the classical model because it does not take multicompartments and desorption rates into consideration. A new multicompartment louver-tide theory is thus developed considering that adsorption is an indefinite dynamic equilibrium process, which can be divided into innumerable ingredients with different desorption rates. This theory produces much better fits to the experimental data and provides a quantitative explanation with multicompartments and adsorption/desorption rates.

Simultaneous separation and purification of total polyphenols, chlorogenic acid and phlorizin from thinned young apples

An efficient preparative separation of polyphenols from thinned young apples (TYA) has been developed in the present study. X-5 resin was verified to offer the best adsorption capacity and desorption ratio for total polyphenols among the eight macroporous resins investigated. Influential factors, such as pH value and concentration of feeding solution, strippant, and adsorption isotherm to the separation of total polyphenols, were successively investigated on X-5 resin. After one run treatment, the phenolic content was increased 2.12-fold from 35.17% to 74.64%, with a recovery yield of 89.35%. Chlorogenic acid and phlorizin were selectively purified using X-5 and polyamide resins. The contents of chlorogenic acid and phlorizin were 15.20% and 97.52% with recovery yields of 89.16% and 64.95%, respectively. The method developed will provide a potential approach for its wide industrial and pharmaceutical use.

Salidroside attenuates hydrogen peroxide-induced cell damage through a cAMP-dependent pathway

Salidroside, a major component of Rhodiola rosea L., has shown various pharmacological functions, including antioxidant effects, but the signal transduction pathway of its antioxidant effects is not very clear. In this study, we found that salidroside could attenuate hydrogen peroxide (H₂O₂)-induced HL-7702 cell damage, inhibit H₂O₂-induced cytosolic free Ca²⁺ ([Ca²⁺]i) elevation, scavenge reactive oxygen species (ROS) and increase 3’-5’-cyclic adenosine monophosphate (cAMP) level in a dose-dependent manner, but it couldn’t influence 3’-5’-cyclic guanosine monophosphate (cGMP) levels. Therefore, these results indicated that the antioxidant effects of salidroside were associated with down-regulation of [Ca²⁺]i, ROS occur via a cAMP-dependent pathway.

Salidroside promotes erythropoiesis and protects erythroblasts against oxidative stress by up-regulating glutathione peroxidase and thioredoxin

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola rosea is commonly used in China and Tibet folk medicine for the treatment of high altitude sickness, anoxia and mountain malhypoxia.

AIM OF STUDY

Salidroside (SDS) is an active ingredient of Rhodiola rosea. This study attempted to examine the potential erythropoiesis-stimulating and anti-oxidative effect of SDS in TF-1 erythroblasts.

MATERIALS AND METHODS

The erythropoiesis-promoting effect was determined by treating human TF-1 cells, one of the popular in vitro models for studying erythropoiesis, with SDS in the presence and absence of erythropoietin (EPO) through the measurement of the expression of a series of erythroid markers such as glycophorin A (GPA), transferrin receptor (CD71) and hemoglobin (Hb). The potential protective effect of SDS against H(2)O(2)-induced apoptosis and its underlying mechanism in TF-1 erythroblasts were examined by flow cytometry and Western blot analysis.

RESULTS

SDS promotes erythropoiesis in the EPO-treated cells and it also reduces the number of apoptotic cells in TF-1 erythroblasts after H(2)O(2) treatment probably through the up-regulation of protective proteins thioredoxin-1 (Trx1) and glutathione peroxidase-1 (GPx1).

CONCLUSION

Our study provides evidence to explain the ethnopharmacological role of SDS and Rhodiola rosea in Chinese medicine. Our findings also support the use of SDS as an erythropoiesis-adjuvant agent to correct anemia and malhypoxia.