Sarsaponin

Protective effects of sarsasapogenin against early stage of diabetic nephropathy in rats.[Pubmed:29682805]

Phytother Res. 2018 Aug;32(8):1574-1582.

Rhizome of Anemarrhena asphodeloides Bunge (AA, family Liliaceae) has been widely used in China for thousands of years to treat febrile diseases and diabetes. Steroidal saponins from AA show good antidiabetes effects and ameliorate diabetic complications. This study was designed to investigate the effects of sarsasapogenin (Sar), a major sapogenin from AA, on diabetic nephropathy (DN) in rats, and to explore the possible mechanisms. Diabetic rats were divided into 3 groups treated orally with Sar (0, 20, or 60 mg/kg) and carboxymethylcellulose sodium, whereas normal rats for Sar (0 or 60 mg/kg) and carboxymethylcellulose sodium. We found that chronic treatment with Sar for 9 weeks significantly ameliorated renal dysfunction of diabetic rats, as evidenced by decreases in albuminuria, kidney weight index, serum uric acid, and morphologic changes such as extracellular matrix expansion and accumulation (fibronectin and collagen IV levels, etc.). Meanwhile, Sar treatment resulted in decreases in interleukin-18, NLRP3, and activated caspase 1 levels as well as advanced glycation endproducts (AGEs) and their receptor (RAGE) levels in the renal cortex of diabetic rats. However, Sar has no effects on the above indices in the normal rats. Therefore, Sar can markedly ameliorate diabetic nephropathy in rats via inhibition of NLRP3 inflammasome activation and AGEs-RAGE interaction.

Sarsasapogenin suppresses Abeta overproduction induced by high glucose in HT-22 cells.[Pubmed:29275517]

Naunyn Schmiedebergs Arch Pharmacol. 2018 Feb;391(2):159-168.

The aim of this study is to investigate effects and potential mechanisms of sarsasapogenin (Sar), an active component purified from Rhizoma Anemarrhenae, on high glucose-induced amyloid-beta (Abeta) peptide overproduction in HT-22 cells. HT-22 cells were divided into normal glucose; high glucose (HG); HG co-treated with low, middle, and high concentration of Sar (1, 5, 25 mumol/L); and peroxisome proliferator-activated receptor gamma (PPARgamma) agonist (10 mumol/L pioglitazone). After treatment for 24 h, protein expression of Abeta and beta-site Abeta precursor protein cleaving enzyme 1 (BACE1) and activated PPARgamma level were determined by Western blot; Abeta42 levels were also measured by using both immunofluorescence and ELISA methods. BACE1 activity and mRNA level were assessed by fluorospectrophotometry and quantitative PCR, respectively. Cell viability was assayed with a CCK-8 kit. Elevated Abeta expression and Abeta42 level were found in HG-treated HT-22 cells, accompanied by increased BACE1 protein and mRNA levels as well as enzymatic activity, which was markedly attenuated by three concentrations of Sar and pioglitazone. Moreover, HG reduced nuclear PPARgamma levels, which was reversed by middle and high concentrations of Sar as well as pioglitazone. PPARgamma antagonist GW9662 (20 mumol/L) pretreatment reversed the effect of Sar on BACE1 protein expression in HG-cultured HT-22 cells. Additionally, Sar suppressed HG-induced decreases in cell viability of HT-22 cells. High glucose can induce an increase in Abeta levels and a decrease in cell viability in HT-22 cells, while co-treatment with Sar improves these results, which is mediated likely through activation of PPARgamma and subsequent downregulation of BACE1.

Synthesis of new sarsasapogenin derivatives with antiproliferative and apoptotic effects in MCF-7 cells.[Pubmed:29337037]

Steroids. 2018 Mar;131:23-31.

Sarsasapogenin, a kind of mainly effective component of Anemarrhena asphodeloides Bunge, possesses good antitumor properties. Two series of new sarsasapogenin derivatives were synthesized and evaluated for their cytotoxicities against three human cancer cell lines (HepG2, A549, MCF-7) using the MTT assay. The structure-activity relationship revealed that the N, N-dimethylamino, pyrrolidinyl, and imidazolyl substituted at the C26 position could increase the antitumor efficacy of the 3-oxo sarsasapogenin series of compounds. Compound 4c with pyrrolidinyl substituted at the C26 position exhibited the greatest cytotoxic activity against MCF-7 cell line (IC50=10.66muM), which was 4.3-fold more potent than sarsasapogenin. Action mechanism investigations showed that 4c could inhibit the colony formation and induce the apoptosis of MCF-7 cells. Further researches showed that a decrease in mitochondrial membrane potential and increases in the expression level of cleaved-PARP and the ratio of Bax/Bcl-2 were observed in MCF-7 cells after treatment with 4c, suggesting that the mitochondrial pathway was involved in the 4c-mediated apoptosis. These results show that compound 4c may serve as a lead for further optimization.

Synthesis and evaluation of 26-amino acid methyl ester substituted sarsasapogenin derivatives as neuroprotective agents for Alzheimer's disease.[Pubmed:28687235]

Steroids. 2017 Sep;125:93-106.

Sarsasapogenin, extracted from Anemarrhena asphodeloides Bunge., has been reported to protect neurons from H2O2-induced damage. In the current study, four series of 26-amino acid methyl ester substituted sarsasapogenin derivatives (5a-5e, 5f-5j, 6a-6e and 7a-7e) were synthesized and tested for neuroprotective activity by evaluating their neuroprotective ratio against SH-SHY5Y cell lines. Studies showed that most of the target compounds displayed better neuroprotective effects than that of sarsasapogenin. Structure-activity relationship analysis suggested that 3-methoxy derivatives (5f-5j) were more potent than other series and the phenylalanine methyl ester moiety at C-26 was important for exhibiting apparent neuroprotective activity. It was worth noting that compound 5h exhibited optimal neuroprotective activity (102.2%) compared with sarsasapogenin (27.3%) and trolox (40.5%), and this encouraged us to investigate the cellular mechanism of 5h further. Our investigation revealed that 5h could attenuate H2O2-induced cell damage by inhibiting the expression of cleaved poly (ADP-ribose) polymerase (PARP) and cleaved caspase-3 as well as rescuing the downregulation of brain-derived neurotrophic factor (BDNF) and its tyrosine receptor kinase B (TrkB). Taken together, these results suggest that the representative compound 5h is a profound lead compound for further investigation and the sarsasapogenin skeleton could be a promising structural template for the development of new anti-Alzheimer drug candidates.

Astrocytes mediated the nootropic and neurotrophic effects of Sarsasapogenin-AA13 via upregulating brain-derived neurotrophic factor.[Pubmed:28979677]

Am J Transl Res. 2017 Sep 15;9(9):4015-4025. eCollection 2017.

Rhizoma Anemarrhena, a widely used traditional Chinese medicine, has previously been shown to have neuroprotective effect. Sarsasapogenin-AA13 (AA13) is a novel synthetic derivative of Sarsasapogenin, which is extracted from Rhizoma Anemarrhena. The aim of this study is to investigate the nootropic and neurotrophic effects of AA13 and underlying mechanisms. In vitro, cell viability of rat primary astrocytes treated with AA13 and neurons cultured with conditioned medium of AA13-treated rat primary astrocytes was tested by MTT assays. In vivo, a pharmacological model of cognitive impairment induced by scopolamine was employed and spatial memory of the mice was assessed by Morris water maze. This study found that AA13 increased cell viability of primary astrocytes and AA13-treated astrocyte-conditioned medium enhanced the survival rate of primary neurons. Interestingly, AA13 markedly enhanced the level of BDNF in astrocytes. Furthermore, AA13 (6 mg/kg) improved the cognitive deficits in animal models (p<0.05) and BDNF and PSD95 levels were increased in brain. Therefore, we hypothesize that AA13 exerts nootropic and neurotrophic activities through astrocytes mediated upregulation of BDNF secretion. The results suggest that AA13 could be a potential compound for cognitive impairment after further research.

Sarsasapogenin-AA13 ameliorates Abeta-induced cognitive deficits via improving neuroglial capacity on Abeta clearance and antiinflammation.[Pubmed:28466999]

CNS Neurosci Ther. 2017 Jun;23(6):498-509.

AIMS: Sarsasapogenin has been reported to improve dementia symptoms somehow, probably through modulating the function of cholinergic system, suppressing neurofibrillary tangles, and inhibiting inflammation. However, the role of sarsasapogenin in response to beta-amyloid (Abeta) remains to be delineated. This study aimed to determine the therapeutic effect of sarsasapogenin-13 (AA13, a sarsasapogenin derivative) on learning and memory impairments in Abeta-injected mice, as well as the role of AA13 in neuroglia-mediated antiinflammation and Abeta clearance. METHODS: Focusing on the role of AA13 in regulating glial responses to Abeta, we conducted behavioral, morphological, and protein expression studies to explore the effects of AA13 on Abeta clearance and inflammatory regulation. RESULTS: The results indicated that oral administration of AA13 attenuated the memory deficits of intracerebroventricular (i.c.v.) Abeta-injected mice; also, AA13 protected neuroglial cells against Abeta-induced cytotoxicity. The further mechanical studies demonstrated that AA13 reversed the upregulation of proinflammatory M1 markers and increased the expression of antiinflammatory M2 markers in Abeta-treated cells. Furthermore, AA13 facilitated Abeta clearance through promoting Abeta phagocytosis and degradation. AA13 modulated the expression of fatty acid translocase (CD36), insulin-degrading enzyme (IDE), neprilysin (NEP), and endothelin-converting enzyme (ECE) in neuroglia. CONCLUSION: The present study indicated that the neuroprotective effect of AA13 might relate to its modulatory effects on microglia activation state, phagocytic ability, and expression of Abeta-degrading enzymes, which makes it a promising therapeutic agent in the early stage of Alzheimer's disease (AD).

Novel sarsasapogenin-triazolyl hybrids as potential anti-Alzheimer's agents: Design, synthesis and biological evaluation.[Pubmed:29635167]

Eur J Med Chem. 2018 May 10;151:351-362.

Sarsasapogenin, an active ingredient in Rhizoma anemarrhenae, is a promising bioactive lead compound in the treatment of Alzheimer's disease. To search for more efficient anti-Alzheimer agents, a series of novel sarsasapogenin-triazolyl hybrids were designed, synthesized, and evaluated for their Abeta1-42 aggregation inhibitory activities. Most of these new hybrids displayed potent Abeta1-42 aggregation inhibition. In particular, the promising compounds 6j and 6o displayed a better ability to interrupt the formation of Abeta1-42 fibrils than curcumin. Moreover, 6j and 6o exhibited moderate neuroprotective effects against H2O2-induced neurotoxicity in SH-SY5Y cells. To investigate whether 6j and 6o could improve cognitive deficits, we performed behavioral tests to examine the learning and memory impairments induced by intracerebroventricular injection of Abeta1-42 (ICV-Abeta1-42) in mice and TUNEL staining to observe neuronal apoptosis in the hippocampus. The results obtained indicated that oral treatment with 6j and 6o significantly ameliorated cognitive impairments in behavioral tests and TUNEL staining showed that 6j and 6o attenuated neuronal loss in the brain. Taken together, the results we obtained showed that the sarsasapogenin skeleton could be a promising structural template for the development of new anti-Alzheimer drug candidates, and compounds 6j and 6o have the potential to be important lead compounds for further research.

Microbial biotransformation of bioactive and clinically useful steroids and some salient features of steroids and biotransformation.[Pubmed:29360535]

Steroids. 2018 Aug;136:76-92.

Steroids are perhaps one of the most widely used group of drugs in present day. Beside the established utilization as immunosuppressive, anti-inflammatory, anti-rheumatic, progestational, diuretic, sedative, anabolic and contraceptive agents, recent applications of steroid compounds include the treatment of some forms of cancer, osteoporosis, HIV infections and treatment of declared AIDS. Steroids isolated are often available in minute amounts. So biotransformation of natural products provides a powerful means in solving supply problems in clinical trials and marketing of the drug for obtaining natural products in bulk amounts. If the structure is complex, it is often an impossible task to isolate enough of the natural products for clinical trials. The microbial biotransformation of steroids yielded several novel metabolites, exhibiting different activities. The metabolites produced from pregnenolone acetate by Cunning hamella elegans and Rhizopus stolonifer were screened against tyrosinase and cholinesterase showed significant inhibitory activities than the parent compound. Diosgenin and its transformed sarsasapogenin were screened for their acetyl cholinesterase and butyryl cholinesterase inhibitory activities. Sarsasapogenin was screened for phytotoxicity, and was found to be more active than the parent compound. Diosgenin, prednisone and their derivatives were screened for their anti-leishmanial activity. All derivatives were found to be more active than the parent compound. The biotransformation of steroids have been reviewed to a little extent. This review focuses on the biotransformation and functions of selected steroids, the classification, advantages and agents of enzymatic biotransformation and examines the potential role of new enzymatically transformed steroids and their derivatives in the chemoprevention and treatment of other diseases. tyrosinase and cholinesterase inhibitory activities, severe asthma, rheumatic disorders, renal disorders and diseases of inflammatory bowel, skin, gastrointestinal tract.