Withanolide Profile and Acetylcholinesterase Inhibitory Activity of Two Argentinean Jaborosa Species.

Acetylcholinesterase (AChE) inhibitors are still an important option for managing symptoms of mild to moderate Alzheimer's disease. In this study, we aimed to evaluate the potential in vitro AChE inhibitory activity of two Argentinian endemic Solanaceae species, Jaborosa bergii and J. runcinata. UHPLC-DAD-HRMS metabolite profiling revealed the presence of withanolides in the active CH2Cl2 subextracts. Their fractionation led to the isolation and identification of two known spiranoid withanolides from J. runcinata and three new withanolides with a skeleton similar to that of trechonolide-type withanolides from J. bergii. The known compounds showed moderate AChE inhibitory activity, while the new ones were inactive.

Withanolides production by the endophytic fungus Penicillium oxalicum associated with Withania somnifera (L.) Dunal.

Withanolides are steroidal lactones with diverse bioactive potential and their production from plant sources varies with genotype, age, culture conditions, and geographical region. Endophytic fungi serve as an alternative source to produce withanolides, like their host plant, Withania somnifera (L.) Dunal. The present study aimed to isolate endophytic fungi capable of producing withanolides, characterization and investigation of biological activities of these molecules. The methanolic fungal crude extract of one of the fungal isolates WSE16 showed maximum withanolide production (219 mg/L). The fungal isolate WSE16 was identified as Penicillium oxalicum based on its morphological and internal transcribed spacer (ITS) sequence analysis and submitted in NCBI (accession number OR888725). The methanolic crude extract of P. oxalicum was further purified by column chromatography, and collected fractions were assessed for the presence of withanolides. Fractions F3 and F4 showed a higher content of withanolides (51.8 and 59.1 mg/L, respectively) than other fractions. Fractions F3 and F4 exhibited antibacterial activity against Staphylococcus aureus with an IC50 of 23.52 and 17.39 µg/ml, respectively. These fractions also showed antioxidant activity (DPPH assay with IC50 of 39.42 and 38.71 µg/ml, superoxide anion scavenging assay with IC50 of 41.10 and 38.84 µg/ml, and reducing power assay with IC50 of 42.61 and 41.40 µg/ml, respectively) and acetylcholinesterase inhibitory activity (IC50 of 30.34 and 22.05 µg/ml, respectively). The withanolides present in fraction 3 and fraction 4 were identified as (20S, 22R)-1a-Acetoxy-27-hydroxywitha-5, 24-dienolide-3b-(O-b-D-glucopyranoside) and withanamide A, respectively, using UV, FTIR, HRMS, and NMR analysis. These results suggest that P. oxalicum, an endophytic fungus isolated from W. somnifera, is a potential source for producing bioactive withanolides.

Withania frutescens (L.) Pauquy, a valuable Mediterranean shrub containing bioactive withanolides.

The bushy plant Withania frutescens (L.) Pauquy is well distributed in the West-Mediterranean area, notably in the south of Spain, Algeria and Morocco where is it is used traditionally for the treatment of various human diseases, including diabetes. Unlike the two major species W. somnifera and W. coagulans extensively studied, the genomically close species W. frutescens has been much less investigated. Nevertheless, this shrub species displays a comparable phytochemical profile and marked antioxidant and anti-inflammatory properties, at the origin of reported pharmacological effects and its traditional uses. Here we have analyzed the diversity of biological effects reported with leaves and root extracts of W. frutescens. Hydroalcoholic extracts prepared from the aerial parts of the plant have revealed antihyperglycemic and cell-protective activities along with antimicrobial and anticorrosive effects. The extracts contained diverse polyphenolic compounds and a few alkaloids (calystegines) but most of the observed effects have been attributed to the presence of withanolides which are modified C28 ergostane-type steroids. Our analysis focused in part on specific withanolides found in W. frutescens, in particular an unusual 3-O-sulfated withanolide considered as a potential pro-drug of the major active compound withaferin A (WA) and a lead compound for the development of a potential drug candidate. The mechanism of action of this sulfated WA analogue is discussed. Altogether, our unprecedented extensive analysis of W. frutescens highlighted the pharmacological potential of this atypical medicinal plant. By analogy with the major cultivated Withania species, the market potential of little-known plant is underlined.

Anti-inflammatory effects of three withanolides isolated from Physalis angulata L. in LPS-activated RAW 264.7 cells through blocking NF-κB signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Physalis angulata L. is commonly used in many countries as popular medicine for the treatment of a variety of diseases such as malaria, hepatitis, dermatitis and rheumatism. But the anti-inflammatory active constituents of this medicinal plant and their molecular mechanism are still not elucidated clearly. AIM OF THE STUDY: The aim of the study is to isolate and identify a series of compounds from the ethanolic extract of Physalis angulata L., and to investigate the anti-inflammatory activities in vitro and the molecular mechanism of physagulin A, physagulin C, and physagulin H. MATERIALS AND METHODS: In order to further understand the anti-inflammatory mechanism of the three compounds, their potential anti-inflammatory activities were investigated in vitro in LPS-activated RAW 264.7 macrophage cells by Griess assay, ELISA, Western blot and immunofluorescence methods in the present study. RESULTS: Physagulin A, physagulin C, and physagulin H could not only inhibit the release of NO, PGE2, IL-6 and TNF-α, but also could down-regulate the expression of iNOS and COX-2 proteins. Furthermore, physagulin A, physagulin C, and physagulin H could remarkably block the degradation of IκB-α and the nuclear translocation of NF-κB/p65 in LPS-activated RAW 264.7 cells. However, none of them could inhibit the phosphorylation of MAPKs family proteins ERK, JNK and p38. Thus, the anti-inflammatory actions of physagulin A, physagulin C, and physagulin H were mainly due to the significant inhibition of NF-κB signaling pathway rather than MAPKs signaling pathway. CONCLUSIONS: All the results clearly showed that physagulin A, physagulin C, and physagulin H demonstrated potent anti-inflammatory activity and can be used as novel NF-κB inhibitors. They are potential to be developed as an alternative or complementary agents for inflammatory diseases.

Cytotoxic withanolides from Datura innoxia.

Chemical investigation of the aerial parts (except fruits) of the medicinal, hallucinogen and toxic plant Datura innoxia Mill. [Solanaceae] led to the isolation of the new withanolide, dinnoxolide A (1), along with the known compounds 21,27-dihydroxy-1-oxowitha-2,5,24-trienolide (2), daturamalakin B (3) and withametelin (4). Their structures were established by analysis of their spectroscopic data, including 1D and 2D NMR experiments and MS. Compounds 2 and 3 were isolated as natural products for the first time and the name dinnoxolide B was given to compound 2. The four withanolides showed in vitro cytotoxic activity against U251 (glioblastoma) and SK-LU-1 (lung adenocarcinoma) human cancer cell lines, with IC50 values ranging from 1.2 to 19.6 µM, and also against the noncancerous monkey kidney cell line (COS-7), with IC50 values ranging from 5.0 to 19.7 µM. Compound 4 was two times more active than the reference compound, etoposide, against lung adenocarcinoma cells.

Withanolides isolated from Tubocapsicum anomalum and their antiproliferative activity.

Seven undescribed withanolides (1-7) and six artificial withanolides (8-13), along with 20 known compounds (14-33) were isolated from the aerial parts of Tubocapsicum anomalum. Their structures were confirmed by comprehensive spectroscopic analyses. The absolute configuration of compound 1 was defined by single-crystal X-ray crystallography. All isolates were evaluated for their antiproliferative effects against five human tumor cell lines (Hep3B, MDA-MB-231, SW480, HCT116 and A549), among which compound 24 (tubocapsanolide A) exhibited the highest activities against the MDA-MB-231 cells with an IC50 value of 1.89 ± 1.03 µM. Further studies showed that 24 exhibited significant damage to mitochondria in MDA-MB-231 cells, including excess reactive oxygen species, decreased mitochondrial membrane potential, and apoptosis initiation. In addition, compound 24 also inhibited cell migration. These findings show that tubocapsanolide A may be a promising molecule for triple-negative breast cancer treatment and merit further evaluation.

Withanone from Withania somnifera Attenuates SARS-CoV-2 RBD and Host ACE2 Interactions to Rescue Spike Protein Induced Pathologies in Humanized Zebrafish Model.

PURPOSE: SARS-CoV-2 engages human ACE2 through its spike (S) protein receptor binding domain (RBD) to enter the host cell. Recent computational studies have reported that withanone and withaferin A, phytochemicals found in Withania somnifera, target viral main protease (MPro) and host transmembrane TMPRSS2, and glucose related protein 78 (GRP78), respectively, implicating their potential as viral entry inhibitors. Absence of specific treatment against SARS-CoV-2 infection has encouraged exploration of phytochemicals as potential antivirals. AIM: This study aimed at in silico exploration, along with in vitro and in vivo validation of antiviral efficacy of the phytochemical withanone. METHODS: Through molecular docking, molecular dynamic (MD) simulation and electrostatic energy calculation the plausible biochemical interactions between withanone and the ACE2-RBD complex were investigated. These in silico observations were biochemically validated by ELISA-based assays. Withanone-enriched extract from W. somnifera was tested for its ability to ameliorate clinically relevant pathological features, modelled in humanized zebrafish through SARS-CoV-2 recombinant spike (S) protein induction. RESULTS: Withanone bound efficiently at the interacting interface of the ACE2-RBD complex and destabilized it energetically. The electrostatic component of binding free energies of the complex was significantly decreased. The two intrachain salt bridge interactions (K31-E35) and the interchain long-range ion-pair (K31-E484), at the ACE2-RBD interface were completely abolished by withanone, in the 50 ns simulation. In vitro binding assay experimentally validated that withanone efficiently inhibited (IC50=0.33 ng/mL) the interaction between ACE2 and RBD, in a dose-dependent manner. A withanone-enriched extract, without any co-extracted withaferin A, was prepared from W. somnifera leaves. This enriched extract was found to be efficient in ameliorating human-like pathological responses induced in humanized zebrafish by SARS-CoV-2 recombinant spike (S) protein. CONCLUSION: In conclusion, this study provided experimental validation for computational insight into the potential of withanone as a potent inhibitor of SARS-CoV-2 coronavirus entry into the host cells.

Withanolides from dietary tomatillo suppress HT1080 cancer cell growth by targeting mutant IDH1.

Isocitrate dehydrogenase (IDH) is one key rate-limiting enzyme in the tricarboxylic acid cycle, which is related to various cancers. Tomatillo (Physalis ixocarpa), a special tomato, is widely consumed as nutritious vegetable in Mexico, USA, etc. As a rich source for withanolides, the fruits of P. ixocarpa were investigated, leading to the isolation of 11 type-A withanolides including 4 new ones (1 is an artificial withanolide). All these withanolides were evaluated for their inhibition on mutant IDH1 enzyme activity. Among them, physalin F (11) exhibited potent enzyme inhibitory activity and binding affinity with mutant IDH1. It inhibits the proliferation of HT1080 cells by selectively inhibiting the activity of mutant IDH1. Since Ixocarpalactone A, another major type-B withanolide in this plant, could act on another energy metabolism target PHGDH, the presence of different types of withanolides in tomatillo and their synergistic effect could make it a potential antitumor functional food or drug.

Cytotoxic Physalins from Aeroponically Grown Physalis acutifolia.

Aeroponically grown Physalis acutifolia afforded five new and six known withanolides including 10 physalins. The structures of the new withanolides, acutifolactone (1), 5ß,6ß-epoxyphysalin C (2), 5α-chloro-6ß-hydroxyphysalin C (3), and an inseparable mixture of 5ß,6ß-epoxy-2,3-dihydrophysalin F-3ß-O-sulfate (4) and 5ß,6ß-epoxy-2,3-dihydrophysalin C-3ß-O-sulfate (5), were elucidated by analysis of their spectroscopic data and chemical interconversions. The known withanolides were identified as physalins B (6), D (7), F (8), H (9), I (10), and U (11) by comparison of their spectroscopic data with those reported. Evaluation of 1-11 and the derivatives, 13 and 13a, obtained from 4 and 5 against a panel of four human cancer cell lines [NCI-H460 (non-small-cell lung), SF-268 (CNS glioma), PC-3 (prostate adenocarcinoma), and MCF-7 (breast adenocarcinoma)] and normal human lung fibroblast (WI-38) cells revealed that physalins 2, 3, 8, and 9 exhibited selective cytotoxic activity to at least one of the cancer cell lines tested compared to the normal cells and that 7, 10, and 11 were inactive up to a concentration of 10.0 µM. These data provided some preliminary structure-activity relationships and suggested that the mechanism of cytotoxic activity of physalins may differ from other classes of withanolides.

Elucidation of plasma protein binding, blood partitioning, permeability, CYP phenotyping and CYP inhibition studies of Withanone using validated UPLC method: An active constituent of neuroprotective herb Ashwagandha.

ETHNOPHARMACOLOGICAL RELEVANCE: Withanone (WN), an active constituent of Withania somnifera commonly called Ashwagandha has remarkable pharmacological responses along with neurological activities. However, for a better understanding of the pharmacokinetic and pharmacodynamic behavior of WN, a comprehensive in-vitro ADME (absorption, distribution, metabolism, and excretion) studies are necessary. AIM OF THE STUDY: A precise, accurate, and sensitive reverse-phase ultra-performance liquid chromatographic method of WN was developed and validated in rat plasma for the first time. The developed method was successfully applied to the in-vitro ADME investigation of WN. MATERIAL AND METHODS: The passive permeability of WN was assayed using PAMPA plates and the plasma protein binding (PPB) was performed using the equilibrium dialysis method. Pooled liver microsomes of rat (RLM) and human (HLM) were used for the microsomal stability, CYP phenotyping, and inhibition studies. CYP phenotyping was evaluated using the specific inhibitors. CYP inhibition study was performed using specific probe substrates along with WN or specific inhibitors. RESULTS: WN was found to be stable in the simulated gastric and intestinal environment and has a high passive permeability at pH 4.0 and 7.0 in PAMPA assay. The PPB of WN at 5 and 20 µg/mL concentrations were found to be high i.e. 82.01 ± 1.44 and 88.02 ± 1.15%, respectively. The in vitro half-life of WN in RLM and HLM was found to be 59.63 ± 2.50 and 68.42 ± 2.19 min, respectively. CYP phenotyping results showed that WN was extensively metabolized by CYP 3A4 and1A2 enzymes in RLM and HLM. However, the results of CYP Inhibition studies showed that none of the CYP isoenzymes were potentially inhibited by WN in RLM and HLM. CONCLUSION: The in vitro results of pH-dependent stability, plasma stability, permeability, PPB, blood partitioning, microsomal stability, CYP phenotyping, and CYP inhibition studies demonstrated that WN could be a better phytochemical for neurological disorders.

Pharmacological and pharmacokinetic effect of a polyherbal combination with Withania somnifera (L.) Dunal for the management of anxiety.

ETHNOPHARMACOLOGICAL RELEVANCE: In the Indian system of medicine, Withania somnifera (L.) Dunal, Hemidesmus indicus (R.Br.), Aegle marmelos (L.) Correa, Emblica officinalis Gaertn, Ocimum sanctum (L.) has been mentioned as a remedy for the treatment of anxiety related disorders. Based on their folklore use, a polyherbal combination was derived for the management of anxiety. AIM OF THE STUDY: The present study is aimed to find the best polyherbal combination (PHC), in terms of its pharmacological action, out of two PHC, namely PHC1 and PHC3, prepared based on the previous studies conducted and to carry out the pharmacokinetic (PK) study of the best combination (PHC3). MATERIALS AND METHODS: Pharmacological activities include elevated plus maze model and hole-board test for anti-anxiety screening, gamma amino-butyric acid (GABAA) measurement in brain tissues and superoxide dismutase, lipid peroxidation and reduced glutathione measurement for anti-oxidant screening. RESULTS: PHC3 (100 mg/kg) produced statistically significant (p < 0.05) effect on all the pharmacological outcome measures when compared to alprazolam standard. Therefore, it was chosen for PK study. PK study was carried out using Liquid Chromatography Mass Spectroscopy technique with respect to Withaferin-A. PK parameters such as maximum plasma concentration (Cmax), 16.78 ± 5.32 ng/mL; time of maximum concentration (Tmax), 18 ± 0.12min; half-life (T1/2) 61.20 ± 9.87min; mean residual time (MRT), 7.53 h s; area under the concentration versus time curve (AUC0-1), 1678 ± 34.13 ng/mL; area under the concentration versus time curve from zero to infinity (AUC0-∞), 1705 ± 28.87 ng/mL; total clearance (CL), 290.67 ± 15.89 mL/min and volume of distribution (Vd) 0.054 L were calculated. CONCLUSIONS: The results of the studies revealed that PHC3 possessed significant anxiolytic, anti-oxidant activities and enhanced expression of GABAA mediated inhibition when compared to PHC1. Withaferin-A in PHC3 exhibited a rapid oral absorption in rat plasma. The findings of this study greatly help to provide useful evidence for the development of suitable formulation using PHC3.

New cytotoxic withanolides from Physalis minima.

Phytochemical investigation of Physalis minima led to the isolation of six new withanolides, including physaminilides HK (1-4), two artificial withanolides (5-6), and 19 known ones (7-25). Their structures were elucidated on the basis of spectroscopic analysis, including NMR and electronic circular dichroism (ECD) data. The isolates were evaluated for their cytotoxic activities against A375 human melanoma cells. Compounds 1, 8-9, 12-13, 15-17 and 19 exhibited significant cytotoxic activities with IC50 values in the range of 1.2-7.5 µM.

New anti-inflammatory withanolides from Physalis pubescens fruit.

Physalis pubescens L. is a medicinal plant widely cultivated in northeast of China. Investigation on the extract of P. pubescens fruit led to the isolation and identification of four new withanolides, namely, physapubescins J-M (1, 2, 4 and 5), together with four known analogues (3, 6-8) and fifteen other compounds. Their structures were elucidated on the basis of comprehensive NMR, MS, and ECD spectroscopic data analysis. Among isolates, physapubescin J (1) contained an unusual sulphide linkage, and four withanolides (3, 5, 7 and 8) showed anti-inflammatory potential in LPS-induced RAW264.7 cells. This study supports P. pubescens fruit could be a valuable source of withanolides. Further studies to investigate anti-inflammatory activities of isolated withanolides using in vivo models are warranted.

Withanolides from the genus Exodeconus (Solanaceae). Chemotaxonomical considerations.

Five Exodeconus species were phytochemically analyzed. From the aerial parts of E. pusillus, the 7α,27-dihydroxy-1-oxo-22R-witha-2,5,24-trienolide and three other previously unreported normal-type withanolides were isolated. All the studied species had normal type and/or ring-D aromatic withanolides, and some had already been isolated from other Solanaceae genera, and therefore, these compounds are not chemotaxonomic markers at the generic level. The chemical composition of an undescribed Exodeconus species analyzed here supports the designation of this taxon as a new entity. The integral chemical profile of Exodeconus can be evaluated for its taxonomic implication when a more robust phylogeny of Solanaceae is available that allows the phylogenetic relationships with its closest genera to be clarified.

4ß-Hydroxywithanolide E from Goldenberry (Whole Fruits of Physalis peruviana L.) as a Promising Agent against Chronic Obstructive Pulmonary Disease.

Environmental toxicant- and oxidant-induced [e.g., cigarette smoke (CS)] respiratory oxidative stress and inflammatory response play a vital role in the onset and progression of COPD. The nuclear factor erythroid 2-related factor 2 (Nrf2) represents an important mechanism for regulating intracellular oxidative stress and inflammatory response and is a promising target for developing agents against COPD. Herein, a bioactivity-guided purification of goldenberry (whole fruits of Physalis peruviana L.) led to the isolation of a novel and potent Nrf2 activator 4ß-hydroxywithanolide E (4ß-HWE). Our study indicated that (i) 4ß-HWE activated the Nrf2-mediated defensive response through interrupting Nrf2-Keap1 protein-protein interaction (PPI) via modification of Cys151 and Cys288 cysteine residues in Keap1 and accordingly suppressing the ubiquitination of Nrf2. (ii) 4ß-HWE enhanced intracellular antioxidant capacity and inhibited oxidative stress in normal human lung epithelial Beas-2B cells and wild-type AB zebrafish. (iii) 4ß-HWE blocked LPS-stimulated inflammatory response and inhibited LPS-stimulated NF-κB activation in RAW 264.7 murine macrophages. (iv) 4ß-HWE effectively suppressed oxidative stress and inflammatory response in a CS-induced mice model of pulmonary injury. Collectively, these results display the feasibility of using 4ß-HWE to prevent or alleviate the pathological progression of COPD and suggest that 4ß-HWE is a candidate or a leading molecule against COPD.

UPLC-MS/MS Identification and Quantification of Withanolides from Six Parts of the Medicinal Plant Datura Metel L.

Withanolides from six parts (flower, leaf, stem, root, seed, and peel) of Datura metel L. (D metel L.) obtained from ten production areas in China were identified and quantified by UPLC-MS/MS. A total of 85 withanolides were characterized for the first time using the UPLC-Q-TOF-MS/MS system. Additionally, a simultaneous, rapid and accurate measurement method was developed for the determination of 22 bioactive withanolides from ten production areas with the UPLC-Q-TRAP-MS/MS system. The results show the total withanolide content is highest in the leaves (155640.0 ng/g) and lowest in the roots (14839.8 ng/g). Compared with other production areas, the total content of plants from Dujiangyan was the highest at 82013.9 ng/g (value range of ten areas: 82013.9-42278.5 ng/g). The results also show significant differences in the distribution of withanolides in the different plant parts, as well as across different production areas. This is a breakthrough report providing a simultaneous qualitative and quantitative analysis of 22 withanolides in D. metel L. It could be the basis for the more rational use of various parts of D. metel L., and the expansion of medicinal resources. This work also lays a solid foundation for research on the quality control of D. metel L.

Withania somnifera Extract Enhances Energy Expenditure via Improving Mitochondrial Function in Adipose Tissue and Skeletal Muscle.

 Withania somnifera (WS), commonly known as ashwagandha, possesses diverse biological functions. WS root has mainly been used as an herbal medicine to treat anxiety and was recently reported to have an anti-obesity effect, however, the mechanisms underlying its action remain to be explored. We hypothesized that WS exerts its anti-obesity effect by enhancing energy expenditure through improving the mitochondrial function of brown/beige adipocytes and skeletal muscle. Male C57BL/6J mice were fed a high-fat diet (HFD) containing 0.25% or 0.5% WS 70% ethanol extract (WSE) for 10 weeks. WSE (0.5%) supplementation significantly suppressed the increases in body weight and serum lipids, and lipid accumulation in the liver and adipose tissue induced by HFD. WSE supplementation increased oxygen consumption and enhanced mitochondrial activity in brown fat and skeletal muscle in the HFD-fed mice. In addition, it promoted browning of subcutaneous fat by increasing mitochondrial uncoupling protein 1 (UCP1) expression. Withaferin A (WFA), a major compound of WS, enhanced the differentiation of pre-adipocytes into beige adipocytes and oxygen consumption in C2C12 murine myoblasts. These results suggest that WSE ameliorates diet-induced obesity by enhancing energy expenditure via promoting mitochondrial function in adipose tissue and skeletal muscle, and WFA is a key regulator in this function.

Isolation and characterization of cytotoxic withanolides from the calyx of Physalis alkekengi L. var franchetii.

Phytochemical investigation into the calyx of Physalis alkekengi L. var franchetii (Mast) Makino resulted in the isolation of ten cytotoxic withanolides, including five new withanolides, 1-5. Compounds 2-4 were obtained as epimeric withaphysalins. The new structures were elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. The withanolides were evaluated for their cytotoxic activities against the A549 and K562 cell lines. Compounds 1 and 8 exhibited potent cytotoxic activity against both cell lines with IC50 values of 1.9-4.3 µM and induced typical apoptosis as evaluated by flow cytometric analysis. Further studies indicated that 1 and 8 displayed antitumour effects by suppressing the PI3K-Akt-mTOR signalling pathway.

In Silico Elucidation of the Plausible Inhibitory Potential of Withaferin A of Withania Somnifera Medicinal Herb Against Breast Cancer Targeting Estrogen Receptor.

BACKGROUND: Estrogen Receptors (ER) are members of the nuclear intracellular receptors family. ER once activated by estrogen, it binds to DNA via translocating into the nucleus and regulates the activity of various genes. Withaferin A (WA) - an active compound of a medicinal plant Withania somnifera was reported to be a very effective anti-cancer agent and some of the recent studies has demonstrated that WA is capable of arresting the development of breast cancer via targeting estrogen receptor. OBJECTIVE: The present study is aimed at understanding the molecular level interactions of ER and Tamoxifen in comparison to Withaferin A using In-silico approaches with emphasis on Withaferin A binding capability with ER in presence of point mutations which are causing de novo drug resistance to existing drugs like Tamoxifen. METHODS: Molecular modeling and docking studies were performed for the Tamoxifen and Withaferin A with the Estrogen receptor. Molecular docking simulations of estrogen receptor in complex with Tamoxifen and Withaferin A were also performed. RESULTS: Amino acid residues, Glu353, Arg394 and Leu387 was observed as crucial for binding and stabilizing the protein-ligand complex in case of Tamoxifen and Withaferin-A. The potential of Withaferin A to overcome the drug resistance caused by the mutations in estrogen receptor to the existing drugs such as Tamoxifen was demonstrated. CONCLUSION: In-silico analysis has elucidated the binding mode and molecular level interactions which are expected to be of great help in further optimizing Withaferin A or design / discovery of future breast cancer inhibitors targeting estrogen receptor.

New withanolides with anti-inflammatory activity from the leaves of Datura metel L.

Twenty three undescribed withanolides, daturmetelides A-W (1-23), were isolated from 70% EtOH extract of the leaves of Datura metel L. The structural characterizations and relative configurations of 1-23 were elucidated by extensive spectroscopic analysis as well as by comparison with literature values. The absolute configurations of 1 and 3 were determined by X-ray crystallography. Bioassay results showed that 1 and 7 exhibited moderate inhibitory effects against NO production in lipopolysaccharide-stimulated RAW 264.7 cells (IC50 values of 13.74 µM and 13.92 µM, respectively). In addition, 1 and 7 showed significant anti-inflammatory activities against the production of TNF-α, IL-1ß, IL-6 and COX-2. Western blot analysis was further performed to reveal the mechanism of anti-inflammatory action via inhibition of the NF-κB activation.