Withanolides from Withania somnifera roots

Two new and seven known withanolides along with beta-sitosterol, stigmasterol, beta-sitosterol glucoside, stigmasterol glucoside, alpha+beta glucose were isolated from the roots of Withania somnifera. Among the known compounds, Viscosa lactone B, stigmasterol, stigmasterol glucoside and alpha+beta glucose are being reported from the roots of W. somnifera for the first time. One of the new compounds contained the rare 16beta-acetoxy-17(20)-ene the other contained unusual 6alpha-hydroxy-5,7alpha-epoxy functional groups in the withasteroid skeleton. The structures were elucidated by spectroscopic methods and chemical transformations.     

Phytochemical and genetic analysis in selected chemotypes of Withania somnifera

The main active components and genetic profile of 15 selected accessions of Withania somnifera Dunal. were analysed. Ethanolic extract of the dried roots/leaves of the plant was concentrated under pressure at 50+/-5 degrees C and was analysed for main compounds (withanolides and withaferin A) by HPLC. All the main components were found to be present in accessions (AGB 002, AGB 009, RSS 009, RSS 033). Correlation of these main components with their genetic factors, was undertaken using AFLP (amplified fragment length polymorphism) markers. Among 64 primers 7 yielded optimum polymorphism. A total of 913 polymorphic peaks were generated using these primers. Jaccard's similarity coefficient indicated that accessions having almost the same active compounds clustered together. The present study demonstrates that AFLP can be successfully used to resolve the correlation of AFLP data with the presence of secondary metabolites.     

Enhancement of antitumor effect of paclitaxel in combination with immunomodulatory Withania somnifera on benzo(a)pyrene induced experimental lung cancer

The current experimental work deals with the immunomodulatory studies on the extract of Withania somnifera (L.) Dunal root powder against benzo(a)pyrene induced lung cancer in male Swiss albino mice. In our previous study, we reported the antioxidant and anticarcinogenic effect of W. somnifera (L.) Dunal along with paclitaxel. Immune dysfunction has been found to be associated with cancer and chemotherapy. Benzo(a)pyrene induced cancer animals were treated with 400mg/kg bodyweight of W. somnifera (L.) Dunal extract for 30 days significantly alters the levels of immunocompetent cells, immune complexes and immunoglobulins. Based on the data, the carcinogen as well as the paclitaxel affects the immune system, the toxic side effects on the immune system is more reversible and more controllable by W. somnifera (L.) Dunal. These results concluded the immunomodulatory activity of W. somnifera (L.) Dunal extract, which is a known immunomodulator in indigenous medicine.     

The neuroprotective effect of Withania somnifera root extract in MPTP-intoxicated mice: An analysis of behavioral and biochemical varibles

We studied the influence of Withania somnifera (Ws) root extract (100 mg/kg body weight) on parkinsonism induced by 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP; i.p, 20 mg/kg body weight for 4 days), via the analysis of behavioral features and the oxidant-antioxidant imbalance in the midbrain of mice. A significant alteration in behavior, increased levels of thiobarbituric acid reactive substance (TBARS), and increased activities of superoxide dismutase (SOD) and catalase (CAT) were noticed in this region of brain in MPTP-treated mice. Oral treatment with the root extract resulted in a significant improvement in the mice’s behavoiur and antioxidant status, along with a significant reduction in the level of lipid peroxidation. The results indicated that at least part of the chronic stress-induced pathology may be due to oxidative stress, which is mitigated by Ws. Further studies are needed to assess the precise mechanism to support the clinical use of the plant as an antiparkinsonic drug.     

Purification and characterization of a glycoprotein inhibitor of toxic phospholipase from Withania somnifera

A phospholipase inhibitor (WSG) has been purified from Withania somnifera using gel-filtration and ion-exchange chromatographies. The WSG is an acidic glycoprotein. Its molecular mass as determined by SDS-PAGE was 27kDa. It neutralized the enzyme activity and pharmacological properties such as cytotoxicity, edema, and myotoxicity of a multi-toxic Indian cobra venom phospholipase (NNXIa-PLA) but failed to neutralize the neurotoxicity. The glycan part of the molecule does not appear to be involved in any of the pharmacological properties studied. The results suggest that the neutralization of the pharmacological effects of the toxic phospholipase is brought about by inhibition of the enzyme activity by formation of a complex between the WSG and the toxic phospholipase. We report the purification and characterization of a glycoprotein phospholipase A inhibitor from Withania somnifera, medicinal plant.     

Structural characterization of a flavonoid glycosyltransferase from Withania somnifera

Medicinal plants are extensively utilized in traditional and herbal medicines, both in India and around the world due to the presence of diverse low molecular weight natural products such as flavonoids, alkaloids, terpenoids and sterols. Flavonoids which have health benefits for humans are the large class of phenylpropanoid-derived secondary metabolites and are mostly glycosylated by UDP-glycosyltransferases (UGTs). Although large numbers of different UGTs are known from higher plants, very few protein structures have been reported till now. In the present study, the three-dimensional model of flavonoid specific glycosyltransferases (WsFGT) from Withania somnifera was constructed based on the crystal structure of plant UGTs. The resulted model was assessed by various tools and the final refined model revealed GT-B type fold. Further, to understand the sugar donors and acceptors interactions with the active site of WsFGT, docking studies were performed. The amino acids from conserved PSPG box were interacted with sugar donor while His18, Asp110, Trp352 and Asn353 were important for catalytic function. This structural and docking information will be useful to understand the glycosylation mechanism of flavonoid glucosides.

Abbreviations

DOPE - Discrete Optimized Potential Energy, PDB - Protein Data Bank, PSPG - Plant Secondary Product Glycosyltransferase, RMSD - Root Mean Squared Deviation, UDP - Uridine diphosphate, UGT - UDP-glycosyltransferases.     

Immunomodulatory effect of Withania somnifera supplementation diet in the giant freshwater prawn Macrobrachium rosenbergii (de Man) against Aeromonas hydrophila

The effect of Withania somnifera extract supplementation diets on innate immune response in giant freshwater prawn Macrobrachium rosenbergii (de Man) against Aeromonas hydrophila was investigated. The bacterial clearance efficiency significantly increased in prawn fed with 0.1% and 1.0% doses of W. somnifera supplementation diet against pathogen from weeks 1-4 as compared to the control. The innate immune parameters such as, phenoloxidase activity, superoxide anion level, superoxide dismutase activity, nitrate, and nitrite concentrations were significantly enhanced in prawn fed with 0.1% and 1.0% doses of W. somnifera supplementation diet from weeks 1-4 against pathogen. The total hemocyte counts (THC) significantly increased in prawn fed with 0.1% and 1.0% doses diet from weeks 1-4 against pathogen as compared to the control. These results strongly suggested that administration of W. somnifera through supplementation diet positively enhances the innate immune system and enhanced survival rate in M. rosenbergii against A. hydrophila infection.     

Unusually sulfated and oxygenated steroids from Withania somnifera

Four (1, 8-10) and six known (2-7) withanolides were isolated from the leaves of Withania somnifera. Among the new compounds, 10 possessed the rare 3-O-sulfate group with the saturation in A ring and 9 contained unusual 1,4-dien-3-one group. Compound 8 did not have usual 2,3 unsaturation in A ring while 1 had the rare C-16 double bond. The structures of all the compounds were elucidated by spectroscopic methods and chemical transformation.     

A standardized root extract of Withania somnifera and its major constituent withanolide-A elicit humoral and cell-mediated immune responses by up regulation of Th1-dominant polarization in BALB/c mice

The effects of graded doses of a chemically standardized aqueous alcoholic (1:1) root extract (AGB) of Withania somnifera on the immune system of SRBC immunized BALB/c mice were investigated. Mice were administrated AGB orally for 15 days. AGB stimulated cell mediated immunity, IgM and IgG titers reaching peak value with 30 mg/kg b.wt. Flow cytometric analysis of lymphocyte surface markers of T cells (CD3(+), CD4(+) and CD8(+)) and B cells (CD19(+)) indicated prominent enhancement in proliferation and differentiation of lymphocytes. The extract selectively, induced type 1 immunity because it guided enhanced expression of T helper cells (Th)1 cytokines interferon (IFN)-gamma and interleukin (IL)-2 while Th2 cytokine IL-4 observed a moderate decline. Confirmation of Th1 polarization was obtained from augmented levels of IgG2a over IgG1 in the blood sera of AGB treated groups. Withanolide-A, a major constituent of AGB appeared responsible for Th1 skewing effect of the extract as it significantly increased the levels of Th1 cytokines, decreased moderately IL-4 and significantly restored the selective dexamethasone inhibition of Th1 cytokines in mouse splenocytes cultures in vitro. In addition, AGB also strongly activated macrophage functions ex vivo and in vitro indicated by enhanced secretion of nitrite, IL-12 and TNF-alpha. In contrast IL-10 remained unchanged again suggesting that AGB critically influenced Th1 profile of the cytokines. The studies suggested that AGB supports predominantly Th1 immunity with increase in macrophage functions. The standardized root extract of no toxicological consequences might therefore, find useful applications against the intracellular pathogens and in the management of immune suppressed diseases.     

Germination behaviour of seeds of Withania somnifera (L.) Dunal: a high value medicinal plant

In order to evolve a quick method for smooth and optimum germination for Withania somnifera- a medicinally efficacious multipurpose plant, present investigation was carried to study the effect of physico-chemical treatments, storage, temperature, photoperiod and growth regulators (GA₃, IAA, IBA, 2–4 D and BA) on germinability. The most effective treatment is GA₃ at 150 μg/ml concentration at 25 °C. The optimal temperature for germination is 25 °C and continuous light favored germination showing that photoperiod has a significant role. The seedlings derived from seeds performed well when grown in a glasshouse. The data have implications for conservation and cultivation of the species studied.     

Purification of a post-synaptic neurotoxic phospholipase A2 from Naja naja venom and its inhibition by a glycoprotein from Withania somnifera

A post-synaptic neurotoxic phospholipase A(2) (PLA(2)) has been purified from Indian cobra Naja naja venom. It was associated with a peptide in the venom. The association was disrupted using 8 M urea. It is denoted to be a basic protein by its behavior on both ion exchange chromatography and electrophoresis. It is toxic to mice, LD(50) 1.9 mg/kg body weight (ip). It is proved to be post-synaptic PLA(2) by chymographic experiment using frog nerve-muscle preparation. A glycoprotein, (WSG) was isolated from a folk medicinal plant Withania somnifera. The WSG inhibited the phospholipase A(2) activity of NN-XIa-PLA(2,) isolated from the cobra venom, completely at a mole-to-mole ratio of 1:2 (NN-XIa-PLA(2): WSG) but failed to neutralize the toxicity of the molecule. However, it reduced the toxicity as well as prolonged the death time of the experimental mice approximately 10 times when compared to venom alone. The WSG also inhibited several other PLA(2) isoforms from the venom to varying extent. The interaction of the WSG with the PLA(2) is confirmed by fluorescence quenching and gel-permeation chromatography. Chemical modification of the active histidine residue of PLA(2) using p-brophenacyl bromide resulted in the loss of both catalytic activity as well as neurotoxicity of the molecule. These findings suggest that the venom PLA(2) has multiple sites on it; perhaps some of them are overlapping. Application of the plant extract on snakebite wound confirms the medicinal value associated with the plant.     

Unusual withanolides from aeroponically grown Withania somnifera

In an attempt to maximize production and the structural diversity of plant metabolites, the effect of growing the medicinal plant Withania somnifera under soil-less aeroponic conditions on its ability to produce withaferin A and withanolides was investigated. It resulted in the isolation and characterization of two compounds, 3α-(uracil-1-yl)-2,3-dihydrowithaferin A (1) and 3β-(adenin-9-yl)-2,3-dihydrowithaferin A (2), in addition to 10 known withanolides including 2,3-dihydrowithaferin A-3β-O-sulfate. 3β-O-Butyl-2,3-dihydrowithaferin A (3), presumably an artifact formed from withaferin A during the isolation process was also encountered. Reaction of withaferin A with uracil afforded 1 and its epimer, 3β-(uracil-1-yl)-2,3-dihydrowithaferin A (4). The structures of these compounds were elucidated on the basis of their high resolution mass and NMR spectroscopic data.     

Comprehensive metabolic fingerprinting of Withania somnifera leaf and root extracts

Profiling of metabolites is a rapidly expanding area of research for resolving metabolic pathways. Metabolic fingerprinting in medicinally important plants is critical to establishing the quality of herbal medicines. In the present study, metabolic profiling of crude extracts of leaf and root of Withania somnifera (Ashwagandha), an important medicinal plant of Indian system of medicine (ISM) was carried out using NMR and chromatographic (HPLC and GC-MS) techniques. A total of 62 major and minor primary and secondary metabolites from leaves and 48 from roots were unambiguously identified. Twenty-nine of these were common to the two tissues. These included fatty acids, organic acids, amino acids, sugars and sterol based compounds. Eleven bioactive sterol-lactone molecules were also identified. Twenty-seven of the identified metabolites were quantified. Highly significant qualitative and quantitative differences were noticed between the leaf and root tissues, particularly with respect to the secondary metabolites.     

Direct shoot regeneration from node,internode, hypocotyl and embryo explants of Withania somnifera

In vitro studies were initiated with Withania somnifera (L.) Dun. for rapid micropropagation of selected chemotypes using nodes, internodes, hypocotyls and embryo explants. Direct regeneration of shoot buds was observed in MS basal medium supplemented with various concentrations of either benzyladenine (BA) or thidiazouron (TDZ) depending on the explant. Nodal explants formed multiple shoots both from pre-existing and de novo buds on Murashige and Skoog's medium (MS) containing 0.1–5.0 mg l⁻¹ BA and a ring of de novo shoot buds on MS medium containing 0.2 and 0.3 mg l⁻¹ TDZ. Internodal explants formed shoot buds on MS with 1.0 and 5.0 mg l⁻¹ BA while the hypocotyl explants gave rise to multiple shoots only on MS with 0.5 mg l⁻¹ BA. Isolated embryos gave rise to many shoot buds on MS with 0.2 and 0.3 mg l⁻¹ TDZ. The shoot buds elongated and rooted either on MS medium with 0.01 mg l⁻¹ BA or on half strength MS medium lacking growth regulators, which depended upon the growth regulator used in the shoot bud induction medium. Except for the embryo-derived plantlets, all other plantlets could be acclimatized with 100% success. This revised version was published online in June 2006 with corrections to the Cover Date.     

Regeneration of plants from alginate-encapsulated shoot tips of Withania somnifera (L.) Dunal, a medicinally important plant species

A protocol was developed for plant regeneration from encapsulated shoot tips collected from in vitro proliferated shoots of Withania somnifera. The best gel composition was achieved using 3% sodium alginate and 75 mM CaCl2.2H2O. The maximum percentage response (87%) for conversion of encapsulated shoot tips into plantlets was achieved on MS medium supplemented with 0.5 mg/l IBA after 5 weeks of culture. The conversion of encapsulated shoot tips into plantlets also occurred when calcium alginate beads having entrapped propagules were directly sown in autoclaved soilrite moistened with 14-MS salts.     

Chondroprotective potential of root extracts of <Emphasis Type="Italic">Withania somnifera</Emphasis> in osteoarthritis

This is the first report describing two novel chondroprotective activities of aqueous extracts of Withania somnifera root powder. First, these extracts had a statistically significant, short-term chondroprotective effect on damaged human osteoarthritic cartilage matrix in 50% of the patients tested. Second, these extracts caused a significant and reproducible inhibition of the gelatinase activity of collagenase type 2 enzyme in vitro.     

Fungal foliar diseases in Withania somnifera and its effect on secondary metabolites

Withania somnifera is a promising revitalizing medicinal herb. The plant is affected by foliar diseases in Lakkavalli forest region of Bhadra Wildlife Sanctuary. The symptomatology of foliar fungal disease incidence, severity and distribution in the study area was examined during 2006–2009. The seedborne nature and transmission of the causal pathogen and its management with seed dressing fungicides were studied. The results of the study indicated that Alternaria alternata caused severe leaf spot disease, while Myrothecium roridum and Fusarium oxysporum caused minor diseases. Based on the internal transcribed spacer (ITS1 and ITS2) regions of rDNA, the major pathogen was identified as A. alternata. The disease is homogeneously distributed in Lakkavalli forest region and high severity is recorded during November. Alternaria alternata and Fusarium oxysporum were the dominant seedborne pathogens that are transmitted to seedlings. Among the seed dressing fungicides used, Hyzeb was the most effective, followed by Captra, Antracol and Bavistin, in reducing the incidence of A. alternata and other seedborne fungi. The infected W. somnifera foliages had decreased steroids and alkaloids and increased phenolics and flavonoids. Analysis of alkaloids in diseased foliages by high performance thin layer chromatography indicated the occurrence of transformed compounds at R_f = 0.1, 0.77 (254 nm) and 0.2 (366 nm).     

Modulation of TCA cycle enzymes and electron transport chain systems in experimental lung cancer

The modulatory effect of Withania somnifera along with paclitaxel on tricarboxylic acid (TCA) cycle key enzymes and electron transport chain complexes were investigated against lung cancer induced by benzo(a)pyrene in Swiss albino mice. Decreased activities of TCA cycle key enzymes such as isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and alpha-ketoglutarate dehydrogenase (alpha-KGDH) in lung cancer bearing animals were observed. Upon W. somnifera along with paclitaxel administration the above biochemical changes were inclined towards normal control animal values. Activities of mitochondrial enzymes and electron transport complexes were analyzed in the experimental groups to determine the efficiency of energy production. This study further confirms the chemotherapeutic effect of W. somnifera along with paclitaxel which is found to be more effective in the treatment of lung cancer. Thus these results are consistent with our hypothesis that the combination chemotherapy of W. somnifera along with paclitaxel as a promising chemotherapeutic agent.