Novel immunosuppressive pregnane glycosides from the leaves of Epigynum auritum

Dimeric benzylisoquinoline alkaloids from Thalictrum delavayi and their biological activities

A phytochemical investigation of the whole plants of T. delavayi led to the isolation of five new dimeric benzylisoquinoline alkaloids, thalidelavines A-E (1-5), together with six known congeners (6-11). The structures and absolute configurations of new compounds were established based on analyses of spectroscopic data, ECD calculations, and single crystal X-ray crystallography. Thalidelavines A-E (1-5) were structurally complex bisbenzylisoquinoline alkaloids with various configurations. These isolated alkaloids were evaluated for their cytotoxic and immunosuppressive effects. Among them, both 9 and 10 displayed significant cytotoxicities against T98G cell lines with an IC₅₀ value of 2.1 μM, compared with the positive CPT-11 (IC₅₀ = 3.0 μM). In addition, 5-7 showed remarkable immunosuppressive effects. These findings not only enrich the structural diversity of bisbenzylisoquinoline alkaloids, but also provide potential candidates for the further development of the antitumor and immunosuppressive agents.

Two New Phenolic Glycosides with Lactone Structural Units from Leaves of Ardisia crenata Sims with Antibacterial and Anti-Inflammatory Activities

Two new lactones, named Ardisicreolides A–B (1–2), together with four known flavonoids, Quercetin (3), Myricetrin (4), Quercitrin (5), Tamarixetin 3-O-rhamnoside (6), were isolated from the ethyl acetate portion of 70% ethanol extracts of dried leaves from Ardisia crenata Sims. These compounds were identified from Ardisia crenata Sims for the first time. The structures of 1–6 were elucidated according to 1D and 2D-NMR methods and together with the published literature. All of the isolated compounds were evaluated for in vitro anti-microbial effect against Escherichia coli, Pseudomonas aeuroginosa, Enterococcus faecalis, Proteus vulgaris, Staphylococcus aureus, and Bacillus subtilis. In addition, compounds 1–2 were assessed for anti-inflammatory activity by acting on LPS-induced RAW 264.7 macrophage cells in vitro. The results showed that only compound 2 exhibited moderate antibacterial activity on Bacillus subtilis. Moreover, compounds 1 and 2 were found to significantly inhibit the production of nitric oxide (NO) and reduce the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-4 (IL-4), and interleukin-10 (IL-10) in LPS-induced RAW 264.7 macrophage cells. The present data suggest that lactones from the leaves of A. crenata Sims might be used as a potential source of natural anti-inflammatory agents.

Hypoglycemic and hypolipidemic effects of Epigynum auritum in high fat diet and streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Epigynum auritum is mainly distributed in Southwest China, and has been used as a "dai" folk medicine with promising Besides, the leaves and barks of E. auritum have detoxifying, analgesic and relieving swelling effects. Previous studies evidenced that E. auritum was rich in pregnanes and their glycosides. However, the hypoglycemic and hypolipidemic effects of the extract from E. auritum (EAE) and its molecular mechanism are still not studied.

AIM OF THE STUDY

The aim of this study is to investigate the hypoglycemic and hypolipidemic effects of EAE on high-fat diet and streptozocin-induced type 2 diabetic rats.

MATERIALS AND METHODS

The high-fat diet and streptozocin induced type 2 diabetic model was established. The diabetic rats were treated with 70% ethanol extract of E. auritum (100 and 300 mg/kg/d) or metformin (DMBG, 100 mg/kg/d) every day for 4 weeks. Fasting blood glucose was recorded weekly. The phenotypic changes were evaluated by the measurement of biochemical indexes and immunohistochemical. The expressions of signaling-related proteins were explored by western blotting.

RESULTS

EAE could effectively regulate the metabolism of glucose and lipids in diabetic rats by increasing insulin sensitivity. In addition, EAE ameliorated the oxidative stress damage and further mitigated the liver, kidney, and pancreatic damage. Mechanism research results show that EAE treatment increased the phosphorylation of Akt, AMPK and GSK-3β, up-regulated the expression of GLUT-2, GLUT-4 and PPAR-α, and reduced PPAR-γ and FAS expressions.

CONCLUSION

EAE exhibited significant hypoglycemic and hypolipidemic effects in HFD/STZ-induced diabetes rats. The mechanism may be related to the effective upregulation of AMPK/Akt/GSK-3β pathway and the decreased expression of PPAR-γ and FAS. It could be a promising natural product with potential value for the development of drugs to prevent or treat type 2 diabetic.

Pregnane glycosides from Adonis amurensis and their bioactivity

Seven undescribed pregnane glycosides named amurensides A-G and two known aglycones were isolated from the whole herb of Adonis amurensis Regel & Radde. Their structures were established based on 1D and 2D NMR spectroscopic analyses, high-resolution mass spectrometry, and acid hydrolysis. The cytotoxicity of all compounds against three tumor cell lines (HepG2, Caco-2, and A549) were evaluated. Among them, amurensides A-C and E showed moderate inhibitory effects on the growth of HepG2 cells, with IC₅₀ values ranging from 15.6 to 48.7 μM (sorafenib, 7.5 ± 1.9 μM). Amurensides A、D and F displayed inhibitory effects on the growth of A549 cells with IC₅₀ values of 18.8 ± 1.2, 12.4 ± 0.6, and 30.4 ± 0.1 μM (cis-platinum, 6.1 ± 0.1 μM), respectively.

Structurally diverse biflavonoids from the fruits of Citrus medica L. var. sarcodactylis Swingle and their hypolipidemic and immunosuppressive activities

The fruit of Citrus medica L. var. sarcodactylis Swingle is not only used as a traditional medicinal plant, but also served as a delicious food. Six new (3'→7″)-biflavonoids (1-6), and twelve known biflavonoid derivatives (7-18) were isolated and characterized from the fruits of C. medica L. var. sarcodactylis Swingle for the first time. Their structures were determined by extensive and comprehensive analyzing NMR, HR-ESI-MS, UV, and IR spectral data coupled with the data described in the literature. Compounds (1-18) were evaluated for their hypolipidemic activities with Orlistat as the positive control, and assayed for their immunosuppressive activities with Dexamethasone as the positive control, respectively. Among them, compounds (1-3) exhibited moderate inhibition of pancreatic lipase activity by inhibiting 68.56 ± 1.40%, 56.18 ± 1.57%, 53.51 ± 1.59% of pancreatic lipase activities at the concentration of 100 μM, respectively. Compounds (4-6) and 8 showed potent immunosuppressive activities with the IC₅₀ values from 16.83 ± 1.32 to 50.90 ± 1.79 μM. The plausible biogenetic pathway and preliminary structure activity relationship of the selected compounds were scientifically summarized and discussed in this study.

4,21-Secovincanol, a Novel Immunosuppressive Monoterpenoid Indole Alkaloid from Kopsia Hainanensis

4,21-Secovincanol (1), a novel C-21/N-4 cleavage monoterpenoid indole alkaloid, along with four analogs (2-5), were obtained from the aerial parts of Kopsia hainanensis. Structurally, compound 1 might be a derivative of epivincanol (2) via C-21/N-4 cleavage. Their structures were confirmed by means of comprehensive spectroscopic data analysis and comparison with the reported data. All isolates significantly inhibited Con A-stimulated mice splenocytes proliferation at 10-40 μM in a dose-dependent manner in vitro. Especially, compound 3 exhibited potent activities comparable to positive control (Dexamethasone, DXM).

Potent immunosuppressive and anti-inflammatory bisindole alkaloids from Melodinus fusiformis

Phytochemical investigation of Melodinus fusiformis led to a new aspidosperma-aspidosperma bisindole alkaloid (BIA), bis-19β-hydroxyvenalstonidine (1), together with three known BIAs (2-4). The structures were established by extensive analysis of their HRESIMS, NMR data, and comparing with the reported data. BIA 1 is an almost symmetrical structure, linked by C3-C14' bond, while BIAs 2-4 are reported for the first time from the plant. The cytotoxic, immunosuppressive and anti-inflammatory activities of BIAs 1-4 were evaluated in vitro. BIAs 1, 3 and 4 showed good toxicity against MOLT-4 cell lines with IC₅₀ values in the range of 1.5-17.5 -M. BIA 2 exhibited the strongest inhibitory effect against MCF-7 cell lines with an IC₅₀ value of 7.1 μM. BIA 1 significantly inhibited Con A-stimulated mice splenocytes proliferation equal to that of the positive control (DXM) in a concentration-dependent manner. BIAs 1 and 2 were able to decrease the NO production in LPS-induced RAW 264.7 cells at 30 μM concentration. BIA 2 showed similar inhibition of nitric oxide release, compared to that of DXM. Furthermore, BIA 2 remarkably inhibited the levels of IL-6 and TNF-α compared to the LPS induced group. Interestingly, BIA 2 displayed an inhibitory effect on TNF-α production similar to that of dexamethasone at a concentration of 20 μM.

In vitro and in vivo anti-inflammatory effects of different extracts from Epigynum auritum through down-regulation of NF-κB and MAPK signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Epigynum auritum has been historically used as a "dai" or traditional medicine for the treatment of inflammation, swelling and severe pain during injury; these may reduce risk of disease and lead to healthier aging. Apart from this, Epigynum auritum extract was also used in arhritis treatment which is also a type of inflammation. Previous phytochemical studies of E. auritum revealed that steroids are main characteristic components with a number of biological activities (especially immunosuppressive and anti-inflammatory activity) Nevertheless, the underlying mechanism of the E. auritum on inflammatory diseases is still unresolved.

AIM OF THE STUDY

This study aimed to comparatively investigate the anti-inflammatory potential of different fractions from the extract of E. auritum (EAE), with their possible active ingredients to reveal the underlying mechanism.

MATERIALS AND METHODS

The EAE was fractionated by column chromatography with macroporous resin D101 which yielded six fractions. The potential anti-inflammatory properties of different fractions of EAE were evaluated in in vitro and in vivo model. The lipopolysaccharide (LPS)-induced RAW264.7 macrophages cells were used for in vitro studies however two typical acute inflammation murine models (xylene-induced ear edema and carrageenan-induced paw edema) were used for anti-inflammatory studies. The important molecular mechanisms related to inflammation were also analyzed by ELISA, western blotting and immunofluorescence. UHPLC-MS/MS was used to analyze the chemical composition of 100% EAE fraction.

RESULTS

Different EAE fractions (especially the Fr. 100% of MeOH:H₂O) significantly reduced the productions of NO, ROS, TNF-α, and IL-6 by LPS-induced RAW264.7 macrophages and increased the expression of IL-10. The expression levels of iNOS and COX-2 enzymes were significantly down-regulated by 100% EAE fraction. Furthermore, 100% EAE fraction inhibited the phosphorylation of the ERK1/2, JNK, and p38 MAPK, and reduced the nuclear translocation of NF-κB which prevents its activation by blocking the phosphorylation and degradation of inhibitor protein of IκBα. In addition two inflammatory animal models; xylene-induced ear edema and carrageenan-stimulated paw edema were also developed with significantly ameliorated inflammatory cytokines. The treatment of these inflammatory models with 100% EAE fraction (Fr. 100%) suppressed the expressions of elevated inflammatory cytokines. Besides the UHPLC-HRMS/MS analysis was also carried out in which the androstane analogues were found to be as a main chemical components.

CONCLUSION

Different fractions (especially Fr. 100%) exert inhibitory effect on inflammation by regulating the release of inflammatory mediators through the NF-κB and MAPK signaling pathways. The androstane and its derivatives might be performing an important role in the observed anti-inflammatory activity. Therefore, Fr. 100% of EAE could be applied as a potential drug candidate for the prevention and treatment of inflammatory diseases.

New calogenin pregnane glycoside derivative from Huernia saudi- arabica and its Lipase and α-Glucosidase Inhibitory Activities

As ongoing investigation of Huernia saudi-arabica D.V.Field (Asclepiadaceae), a new steroidal pregnane glycoside (Huernioside A) was isolated from dichloromethane fraction (DCM); it was identified as 3β, 11, 14β, 20(R)-tetrahydroxy-pregna-5,9(11)-diene-3-O-β-D-thevetopyranosyl-(1-4)-β-D-cymaropyranoside(HCP) through analysis of 1D, 2D NMR besides ESI-MS data. The alcoholic extract of the aerial part (ALE), DCM and HCP showed inhibitory potential against pancreatic lipase compared to orilstat. Among the tested samples, the ALE and HCP exhibited a promising pancreatic lipase inhibitory commotion through IC₅₀ values of 0.61 ± 0.15, 1.23 ± 0.07 mg/ml (equivalent to 88.8 μM), respectively. HCP was prevailed to have a mixed mode of inhibition as exposed by enzyme kinetic studies. Hydrophobic interactions were the major forces involved in ligand enzyme interactions. In contrast, moderate α-glucosidase inhibitory activities were evidenced for ALE and HCP (% inhibition: 24.8 ± 1.8 and 26.6 ± 2.5, respectively) compared to acarbose. This investigation is the first to report on the possible in vitro anti-obesity and anti-diabetic impact of H. saudi-arabica.

Structurally Diverse Flavonolignans with Immunosuppressive and Neuroprotective Activities from the Fruits of Hippophae rhamnoides L

The fruit of Hippophae rhamnoides L. has been used for centuries in Europe and Asia as a food with high nutritional and medicinal values. In this study, a bioactivity-guided phytochemical investigation of H. rhamnoides L. has resulted in four new dimethylallylated flavonolignans (1-4), four new isopropylpentenone-flavonolignan heterodimers (5-8), two new geranylated flavonolignans (9 and 10), and 14 known flavonolignan derivatives (11-24); they were elucidated by their spectrometric and spectroscopic methods, including HR-ESI-MS, NMR, IR, and UV from the fruit of H. rhamnoides L. for the first time. Among them, compounds 2, 5, 6, 20, and 21 showed potent immunosuppressive activities with IC₅₀ values from 19.42 ± 3.91 to 48.05 ± 12.56 μM. Meanwhile, compounds 1, 4, 11, 12, and 13 showed moderate neuroprotective activities, which increased the cell survival rate from 50.30 ± 4.24% for the model group to 71.63 ± 3.04%, 70.02 ± 4.13%, 61.53 ± 5.93%, 61.08 ± 3.58%, and 65.68 ± 4.88% at 10 μM, respectively. The hypothetical biogenetic pathway and preliminary structure-activity relationship were found and discussed scientifically.

Phenolic Amides with Immunomodulatory Activity from the Nonpolysaccharide Fraction of Lycium barbarum Fruits

The fruits of Lycium barbarum have a long history as an edible and medicinal food in Asian regions and have multiple consumption methods; the polysaccharides (LBPs) are commonly considered as their major immunological constituents. The current study revealed that the total phenolic amide moieties from L. barbarum fruits showed greater potential immunomodulatory activity in vivo than did LBPs. Through subsequent investigation on the immunological bioactive phenolic amides, three new phenolic amides, lyciumamides L-N (1-3), as well as 12 analogues, were obtained from the total phenolic amide fraction. Extensive spectroscopic methods were used to elucidate the new structures. Compounds 4-6 and 15 significantly promoted LPS-stimulated B splenocyte, while compounds 4-6 displayed accelerative effects on the proliferation of Con A-stimulated T lymphocytes at a concentration of 20.0 μg/mL. These data indicated that extracts from L. barbarum fruits enriched with phenolic amides could be developed as a nutritional dietary supplement for immunocompromised individuals.

Epigynumgenane-type pregnane glycosides from Epigynum cochinchinensis and their immunosuppressive activity

Five undescribed C₂₁ pregnane glycosides, epigycosides D-H, together with four known analogues, two lignans, and a flavonoid have been isolated from the stems of Epigynum cochinchinensis. The structures of pregnane glycosides were elucidated using spectroscopic techniques and acid hydrolysis. The in vitro immunological activities were assessed against Con A-stimulated proliferation of mice splenocytes. The C₂₁ pregnane glycosides showed immunosuppressive activity in a concentration-dependent manner. Moreover, epigycoside E exhibited a potent immunosuppressive effect, and the IC₅₀ value on Con A-stimulated mice splenocytes was 22.1 ± 6.4 μM. Epigycoside E also caused G₀/G₁ arrest, and inhibited TNF-α and IL-2 production.

Acute and subacute toxicity evaluation of ethanol extract from aerial parts of Epigynum auritum in mice

Acute and subacute toxicities of the ethanol extract from Epigynum auritum (EAE) wereperformed by oral administration in pathogen-free mice. Acute toxicity study was performed at a single dose of 5000 mg/kg for 14 consecutive days, while subacute toxicity test was conducted by daily oral administration of EAE at doses of 312, 625, 1250, and 2500 mg/kg for 28 days. Acute toxicity study showed that LD₅₀ of EAE was over 5000 mg/kg. The results of subacute toxicity showed no significant adverse effect of EAE at 312 mg/kg. Moreover, EAE exhibited toxicities to liver, spleen and kidney in mice determined by hematological, serum biochemical and histological analyses during daily oral administration of 1250 mg/kg and 2500 mg/kg EAE. The results revealed that the dose of EAE lower than 625 mg/kg can be regarded as safe.

Curtachalasins, immunosuppressive agents from the endophytic fungus Xylaria cf. curta

Eleven new cytochalasins were isolated from Xylaria cf. curta. Their selective immunosuppressive properties provide new clues for drug development of immunosuppressants.

A New Immunosuppressive Pregnane Glycoside and Two Known Analogues from Epigynum cochinchinensis

Phytochemical investigation of the ethyl acetate soluble fraction from the leaves of Epigynum cochinchinensis led to the isolation of one new C21 pregnane glycoside, epigycoside C (1), along with two known analogues epigycoside A (2) and epigynoside G (3). Their structures were elucidated on the basis of extensive spectroscopic techniques. The in vitro immunosuppressive activity of compound 1 was evaluated against concanavalin A (Con A)- and lipopolysaccharides (LPS)-stimulated proliferation of mice splenocytes. Compound 1 displayed significant immunosuppressive activities in a dose-dependent manner.

Immune-inhibitive phenyl-C1 substituent aporphine alkaloids from Thalictrum cirrhosum

Five new phenyl-C₁ substituent aporphine alkaloids, 6aR-2'-methoxycarbonyl-thaliadin (1), 6aR-2'-carboxyl-thaliadin (2), 6aR-3-methoxy-hernandalinol (3), 6aS-1,3,10-trimethoxy-natalamine (4), and 3-methoxy-2'-methoxycarbonyl-oxohernandalincin (5), together with sixteen known isoquinoline alkaloids (6-21) were isolated from the whole herb of Thalictrum cirrhosum (Levl.). Their structures were elucidated by extensive spectroscopic measurements, and six isoquinoline alkaloids showed significant inhibitory activity on concanavalin A-stimulated splenocytes proliferation with IC₅₀ values 36-44 μM by the immunosuppressive bioassay.