Withania somnifera

About: Withania somnifera is a research topic. Over the lifetime, 2116 publications have been published within this topic receiving 43404 citations. The topic is also known as: Ashwaganda & Indian ginseng.

Withania somnifera (Linn.) Dunal: a review of chemical and pharmacological diversity

Abstract: Withania somnifera Dunal, is a commonly used herb in Indian Ayurvedic medicine system. Due to its pharmacological value and an inexhaustible source of novel biologically active compounds, it has been a great interest for researchers. The plant is known to possess anti-inflammatory, antitumor, antistress, antioxidant, immunomodulatory and hemopoetic properties. Various withanolides, steroidal lactones, have been isolated from W. somnifera and were known to have high therapeutic value. Based on the differences in the substitution patterns of withanolides the species has been classified into various chemotypes. So far, three different chemotypes have been identified, which have been further classified into ecotypes based on the contents of withanolides. Present review summarizes the phytochemical variability and pharmacological advances reported in literature.

Sterol glycosyltransferases-identification of members of gene family and their role in stress in Withania somnifera.

Abstract: Sterol glycosyltransferases (SGTs) catalyze the transfer of sugar molecules to diverse sterol molecules, leading to a change in their participation in cellular metabolism. Withania somnifera is a medicinal plant rich in sterols, sterol glycosides and steroidal lactones. Sterols and their modified counterparts are medicinally important and play a role in adaptation of the plant to stress conditions. We have identified 3 members of SGT gene family through RACE (Rapid Amplification of cDNA Ends) in addition to sgtl1 reported earlier. The amino acid sequence deduced from the ORF's showed homology (45-67 %) to the reported plant SGTs. The expression of the genes was differentially modulated in different organs in W. somnifera and in response to external stimuli. Salicylic acid and methyl jasmonate treatments showed up to 10 fold increase in the expression of sgt genes suggesting their role in defense. The level of expression increased in heat and cold stress indicating the role of sterol modifications in abiotic stress. One of the members, was expressed in E. coli and the enzyme assay showed that the crude enzyme glycosylated stigmasterol. W. somnifera expresses a family of sgt genes and there is a functional recruitment of these genes under stress conditions. The genes which are involved in sterol modification are important in view of medicinal value and understanding stress.

Cloning and characterization of 2-C-methyl-d-erythritol-4-phosphate pathway genes for isoprenoid biosynthesis from Indian ginseng, Withania somnifera

Abstract: Withania somnifera (L.) is one of the most valuable medicinal plants used in Ayurvedic and other indigenous medicines. Pharmaceutical activities of this herb are associated with presence of secondary metabolites known as withanolides, a class of phytosteroids synthesized via mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate pathways. Though the plant has been well characterized in terms of phytochemical profiles as well as pharmaceutical activities, not much is known about the genes responsible for biosynthesis of these compounds. In this study, we have characterized two genes encoding 1-deoxy-d-xylulose-5-phosphate synthase (DXS; EC 2.2.1.7) and 1-deoxy-d-xylulose-5-phosphate reductase (DXR; EC 1.1.1.267) enzymes involved in the biosynthesis of isoprenoids. The full-length cDNAs of W. somnifera DXS (WsDXS) and DXR (WsDXR) of 2,154 and 1,428 bps encode polypeptides of 717 and 475 amino acids residues, respectively. The expression analysis suggests that WsDXS and WsDXR are differentially expressed in different tissues (with maximal expression in flower and young leaf), chemotypes of Withania, and in response to salicylic acid, methyl jasmonate, as well as in mechanical injury. Analysis of genomic organization of WsDXS shows close similarity with tomato DXS in terms of exon–intron arrangements. This is the first report on characterization of isoprenoid biosynthesis pathway genes from Withania.