Effect of macronutrient deficiency on withanolides content in the roots of Withania somnifera and its correlationship with molybdenum content

Plant secondary metabolic responses to global climate change: A meta-analysis in medicinal and aromatic plants

Plant secondary metabolites (SMs) play crucial roles in plant-environment interactions and contribute greatly to human health. Global climate changes are expected to dramatically affect plant secondary metabolism, yet a systematic understanding of such influences is still lacking. Here, we employed medicinal and aromatic plants (MAAPs) as model plant taxa and performed a meta-analysis from 360 publications using 1828 paired observations to assess the responses of different SMs levels and the accompanying plant traits to elevated carbon dioxide (eCO₂ ), elevated temperature (eT), elevated nitrogen deposition (eN) and decreased precipitation (dP). The overall results showed that phenolic and terpenoid levels generally respond positively to eCO₂ but negatively to eN, while the total alkaloid concentration was increased remarkably by eN. By contrast, dP promotes the levels of all SMs, while eT exclusively exerts a positive influence on the levels of phenolic compounds. Further analysis highlighted the dependence of SM responses on different moderators such as plant functional types, climate change levels or exposure durations, mean annual temperature and mean annual precipitation. Moreover, plant phenolic and terpenoid responses to climate changes could be attributed to the variations of C/N ratio and total soluble sugar levels, while the trade-off supposition contributed to SM responses to climate changes other than eCO₂ . Taken together, our results predicted the distinctive SM responses to diverse climate changes in MAAPs and allowed us to define potential moderators responsible for these variations. Further, linking SM responses to C-N metabolism and growth-defence balance provided biological understandings in terms of plant secondary metabolic regulation.

Nutritional Composition, Bioactive Compounds, and Volatiles Profile Characterization of Two Edible Undervalued Plants: Portulaca oleracea L. and Porophyllum ruderale (Jacq.) Cass

Wild edible plants are an important source of healthy food and have played an important role in traditional Mediterranean diets. In this paper, quality characteristics were typified in Portulaca oleracea L. and Porophyllum ruderale (Jacq.) Cass, undervalued plants inherent to the spring-summer season in the Valencian coastal region. Nutritional composition and bioactive compounds were analyzed and compared between plants in wild and organic cultivation conditions. Proximate analysis was carried out according to Association of Official Analytical Chemists methods. Total antioxidants were measured as 2.2-diphenyl-1-picrylhydrazyl hydrate and total polyphenols content via the Folin-Ciocalteu procedure. The HS-SPME technique was used to characterize the volatiles profile, and the polyphenol profile was evaluated by HPLC. The most important microelement was iron. Total antioxidants ranged from 4392.16 to 7315.00 μmol Trolox·equivalents 100 g-1 fw, and total phenolic content ranged from 99.09 to 391.18 mg gallic acid equivalents·100 g-1 fw. Results show that the content of antioxidants and phenols was higher in wild species than in cultivated ones. The volatiles profile revealed that P. ruderale was rich in monoterpenoids (48.65-55.82%), and fatty alcohols were characteristic in P. oleracea species (16.21-54.18%). The results suggest that both plants could be healthy foods and could have new sustainable agro-ecological potential for the local commercial sector.

Physalis angulata Calyces Modulate Macrophage Polarization and Alleviate Chemically Induced Intestinal Inflammation in Mice

As part of the search for new bioactive plants from the Colombian Caribbean, the dichloromethane fraction of the calyces of Physalis angulata L. (PADF) was selected for its anti-inflammatory activity. In this work, we investigated the immunomodulatory effect of PADF in activated macrophages and during dextran sulfate sodium (DSS)-induced colitis. PADF displayed a low content of withanolides or phenolic compounds, and a higher content of sucrose esters, representative anti-inflammatory metabolites of the Physalis genus. The PADF fraction at 12.5 μg/mL prevented the induction of interleukin (IL)-1β, tumor necrosis factor (TNF-α), IL-6, IL-12, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) by lipopolysaccharide (LPS), while increased the levels of arginase (ARG1), IL-10, and mannose receptor C (MRC1). The polarization towards an anti-inflammatory profile was also observed in resting macrophages, without promoting the typical gene profile induced by IL-4, suggesting that PADF promotes a shift to a regulatory status rather than to an alternative one. In vivo, the administration of PADF to mice with chronic DSS-colitis reduced disease signs (i.e., body weight loss and colon shortening), and improved the histology score by diminishing the levels of pro-inflammatory cytokines and increasing the production of IL-10. Overall, results suggest that the regulatory effect on PADF towards macrophages might contribute to the therapeutic activity observed in the murine model of inflammatory bowel disease.

Neuroprotective Effect of Ashwagandha Extract against the Neurochemical Changes Induced in Rat Model of Hypothyroidism

The current aim is to evaluate the effect of ashwagandha root extract (AE) on the neurochemical changes induced in the cortex and hippocampus as a consequence of thyroid dysfunction induced by propylthiouracil (PTU). Male Wistar rats were divided into; control, AE treated rats, rat model of hypothyroidism and rat model of hypothyroidism treated with either AE or L-thyroxine (T4) for 1 month. Rat model of hypothyroidism showed a significant decrease in serum levels of tri-iodothyronine (T3) and T4 and a significant increase in cortical and hippocampal lipid peroxidation (MDA), nitric oxide (NO), superoxide dismutase (SOD) and catalase (CAT). However, reduced glutathione (GSH) decreased significantly. This was associated with a significant increase in hippocampal tumor necrosis factor-α (TNF-α) and cortical dopamine levels. Both L-thyroxine and AE restored T3 and T4 levels. In the hippocampus L-Thyroxine prevented the increase in MDA and restored GSH but failed to restore the increased NO and TNF-α. In the cortex L-thyroxine didn't change the increased MDA and NO and the decreased GSH induced by PTU. L-thyroxine increased cortical and hippocampal SOD and CAT. AE prevented the increased hippocampal MDA, NO and TNF-α and the decreased GSH level induced by PTU. In the cortex AE failed to restore MDA and NO but prevented the decrease in GSH. The increase in cortical dopamine level induced by PTU was ameliorated by L-thyroxine and improved by AE. The present data indicate that AE could prevent thyroid dysfunction and reduce its complications on the nervous system including oxidative stress and neuroinflammation.

A WRKY transcription factor from Withania somnifera regulates triterpenoid withanolide accumulation and biotic stress tolerance through modulation of phytosterol and defense pathways

Withania somnifera produces pharmacologically important triterpenoid withanolides that are derived via phytosterol pathway; however, their biosynthesis and regulation remain to be elucidated. A jasmonate- and salicin-inducible WRKY transcription factor from W. somnifera (WsWRKY1) exhibiting correlation with withaferin A accumulation was functionally characterized employing virus-induced gene silencing and overexpression studies combined with transcript and metabolite analyses, and chromatin immunoprecipitation assay. WsWRKY1 silencing resulted in stunted plant growth, reduced transcripts of phytosterol pathway genes with corresponding reduction in phytosterols and withanolides in W. somnifera. Its overexpression elevated the biosynthesis of triterpenoids in W. somnifera (phytosterols and withanolides), as well as tobacco and tomato (phytosterols). Moreover, WsWRKY1 binds to W-box sequences in promoters of W. somnifera genes encoding squalene synthase and squalene epoxidase, indicating its direct regulation of triterpenoid pathway. Furthermore, while WsWRKY1 silencing in W. somnifera compromised the tolerance to bacterial growth, fungal infection, and insect feeding, its overexpression in tobacco led to improved biotic stress tolerance. Together these findings demonstrate that WsWRKY1 has a positive regulatory role on phytosterol and withanolides biosynthesis, and defense against biotic stress, highlighting its importance as a metabolic engineering tool for simultaneous improvement of triterpenoid biosynthesis and plant defense.

Evaluation of the bioavailability of major withanolides of Withania somnifera using an in vitro absorption model system

Withania somnifera (L.) Dunal, shows several pharmacological properties which are attributed mainly to the withanolides present in the root. The efficacy of medicinally active withanolides constituents depends on the absorption and transportation through the intestinal epithelium. We examined these characteristics by employing the Sino-Veda Madin-Darby canine kidney cells culture system, which under in vitro condition shows the absorption characteristics similar to the human intestinal epithelium. Thus, the aim of the present investigation was to assess the bioavailability of individual withanolides. Withanolides were diluted in Hank's buffered saline at a concentration of 2 μg/ml were tested for permeability studies carried out for 1 h duration. Permeability was measured in terms of efflux pump (P_eff) in cm/s. P_eff values of withanolide A (WN A), withanone (WNN), 1,2-deoxywithastramonolide (1,2 DWM), withanolide B (WN B), withanoside IV-V (WS IV-V), and withaferin A were 4.05 × 10⁻⁵, 2.06 × 10⁻⁵, 1.97 × 10⁻⁵, 1.80 × 10⁻⁵, 3.19 × 10⁻⁶, 3.03 × 10⁻⁶ and 3.30 × 10⁻⁷ respectively. In conclusion, the nonpolar and low molecular weight compounds (WN A, WNN, 1,2 DWM, and WN B) were highly permeable. As against this, the glycosylated and polar WS IV and WS V showed low permeability. Surprisingly and paradoxically, the highly biologically active withaferin A was completely impermeable, suggesting that further studies possibly using human epithelial colorectal adenocarcinoma (Caco-2) cells may be needed to delineate the absorption characteristics of withanolides, especially withaferin A.