406 results on '"Steve Thomas"'
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402. Rapid Chemical Profiling of Filipendula ulmaria Using CPC Fractionation, 2-D Mapping of 13 C NMR Data, and High-Resolution LC-MS.
- Author
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Pannakal ST, Eilstein J, Hubert J, Kotland A, Prasad A, Gueguiniat-Prevot A, Juchaux F, Beaumard F, Seru G, John S, and Roy D
- Subjects
- Humans, Chromatography, Liquid, Tandem Mass Spectrometry, Magnetic Resonance Imaging, Epidermis, Filipendula
- Abstract
Filipendula ulmaria , commonly known as meadowsweet, is a wild herbaceous flowering plant that is widely distributed in Europe. A range of salicylic acid derivatives and flavonol glycosides have been previously associated with the antirheumatic and diuretic properties of F. ulmaria . In the present work, a hydroalcoholic extract from F. ulmaria aerial parts was extensively profiled using an efficient NMR-based dereplication strategy. The approach involves the fractionation of the crude extract by centrifugal partition chromatography (CPC),
13 C NMR analysis of the fractions, 2D-cluster mapping of the entire NMR dataset, and, finally, structure elucidation using a natural metabolite database, validated by 2D NMR data interpretation and liquid chromatography coupled with mass spectrometry. The chemodiversity of the aerial parts was extensive, with 28 compounds unambiguously identified, spanning various biosynthetic classes. The F. ulmaria extract and CPC fractions were screened for their potential to enhance skin epidermal barrier function and skin renewal properties using in vitro assays performed on Normal Human Epidermal Keratinocytes. Fractions containing quercetin, kaempferol glycosides, ursolic acid, pomolic acid, naringenin, β -sitosterol, and Tellimagrandins I and II were found to upregulate genes related to skin barrier function, epidermal renewal, and stress responses. This research is significant as it could provide a natural solution for improving hydration and skin renewal properties.- Published
- 2023
- Full Text
- View/download PDF
403. Non-destructive, reverse iontophoretic extraction of phytochemicals from Mangifera indica, Centella asiatica, Punica granatum, and Citrus sinensis.
- Author
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Eilstein J, Nair V, Moore K, Pannakal ST, Grégoire S, Ekhar P, Guy RH, Delgado-Charro MB, and Roy N
- Subjects
- Plant Extracts, Phytochemicals, Pomegranate, Mangifera, Citrus sinensis, Centella
- Abstract
For the commercial-scale isolation of phytochemicals, a suitable plant biomass source (including species, origin, growing season, etc.) must be identified, and frequent analytical verification is required to ensure that the phytochemicals are present at predefined minimum threshold concentrations. While the latter are typically assessed in the laboratory, a more efficient and less resource-intensive approach would involve non-destructive and environmentally friendly measurements in situ. Reverse iontophoretic (RI) sampling offers a potential solution to this challenge., Objective: We aimed to demonstrate the non-destructive, RI sampling of phytochemicals of interest from biomass from four different sources., Materials and Methods: RI experiments were performed in side-by-side diffusion cells using a current density of 0.5 mA/cm
2 , for a predetermined time in a defined pH environment, using (1) fresh leaves from Mangifera indica and Centella asiatica and (2) isolated peel from Punica granatum and Citrus sinensis., Results: Mangiferin, madecassoside, punicalagin, ellagic acid, and hesperidin were extracted from the different biomasses by RI. The amounts extracted ranged from 0.03 mg/100 mg of biomass for the cathodal extraction of madecassoside to 0.63 mg/100 mg of biomass for the anodal extraction of punicalagin. A linear relationship (r2 = 0.73) between the RI-extracted quantities of punicalagin and those determined using conventional methods was demonstrated., Conclusion: The non-destructive, in situ measurement of phytochemical levels by RI represents a feasible approach for timing the harvesting process., (© 2023 L’Oreal R&I and The Authors. Phytochemical Analysis published by John Wiley & Sons Ltd.)- Published
- 2023
- Full Text
- View/download PDF
404. Longevity effect of a polysaccharide from Chlorophytum borivilianum on Caenorhabditis elegans and Saccharomyces cerevisiae.
- Author
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Pannakal ST, Jäger S, Duranton A, Tewari A, Saha S, Radhakrishnan A, Roy N, Kuntz JF, Fermas S, James D, Mellor J, Misra N, and Breton L
- Subjects
- Aging, Animals, Caenorhabditis elegans drug effects, Cell Proliferation drug effects, Dose-Response Relationship, Drug, Keratinocytes drug effects, Saccharomyces cerevisiae drug effects, Asparagaceae, Longevity drug effects, Medicine, Ayurvedic, Plant Extracts pharmacology, Polysaccharides pharmacology
- Abstract
The traditional Indian medicine, Ayurveda, provides insights and practical solutions towards a healthy life style. Rasayana is a branch of Ayurveda known for preserving and promoting health, enhancing the quality of life and delaying the aging process. In the traditional knowledge, the Rasayana herb, Chlorophytum borivilianum (C. borivilanum) is regarded as a general health promoting tonic that delays aging and increases lifespan, cognitive function and physical strength. Aging is a complex and multifactorial physiological phenomenon that manifests itself over a wide range of biological systems, tissues, and functions. Longevity is an obvious marker of physiological aging. Simple model systems such as the single-cell budding yeast Saccharomyces cerevisiae (S. cerevisiae) and the nematode, Caenorhabditis elegans (C. elegans) are widely used to study the aging process and longevity. Here, we show that a polysaccharide fraction obtained from C. borivilianum increases the lifespan of S. cerevisiae and C. elegans, using an automated screening platform (ChronoscreenTM). Chemical analysis of this extract revealed a low molecular weight polysaccharide of 1000 Da, predominantly comprising Glu1→6Glu linkage. This polysaccharide showed significant dose-dependent extension of the median lifespan of S. cerevisiae by up to 41% and of the median lifespan of C. elegans by up to 10%. Taking cue from these results and the traditionally described benefits of Rasayanas on skin rejuvenation, we tested in vitro the polysaccharide for potential skin benefits. In a keratinocyte culture, we observed that this polysaccharide increased cell proliferation significantly, and induced synthesis of hyaluronic acid (HA), a well-known extracellular matrix component. Furthermore, when added to culture medium of human reconstructed epidermis, we observed an enhanced production of epidermal markers, e.g. CD44 and HA that are otherwise diminished in aged skin. Together, these results suggest that in addition to life-span extension of S. cerevisiae and C. elegans, a polysaccharide from the Rasayana herb, C. borivilianum may have beneficial effects on skin aging parameters.
- Published
- 2017
- Full Text
- View/download PDF
405. Antidiabetic, antihyperlipidemic and antioxidant effects of the flavonoid rich fraction of Pilea microphylla (L.) in high fat diet/streptozotocin-induced diabetes in mice.
- Author
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Bansal P, Paul P, Mudgal J, Nayak PG, Pannakal ST, Priyadarsini KI, and Unnikrishnan MK
- Subjects
- Animals, Antioxidants pharmacology, Chromatography, High Pressure Liquid, Diet, High-Fat adverse effects, Flavonoids chemistry, Hypoglycemic Agents pharmacology, Hypolipidemic Agents pharmacology, Male, Mice, Diabetes Mellitus, Experimental drug therapy, Flavonoids pharmacology, Phytotherapy methods, Plant Extracts pharmacology, Urticaceae chemistry
- Abstract
The present study describes the antidiabetic effect of the flavonoid rich fraction of Pilea microphylla (PM1). HPLC characterization of PM1 revealed the presence of polyphenols viz., chlorogenic acid, rutin, luteolin-7-O-glucoside, isorhoifolin, apigenin-7-O-glucoside, and quercetin. PM1 inhibited dipeptidyl peptidase IV (DPP-IV) in vitro with an IC(50) of 520.4±15.4 μg/ml. PM1, at doses of 300, 600 and 900 mg/kg i.p., also produced dose-dependent mean percent reductions of 9.9, 30.6 and 41.0 in glucose excursion (AUC(0-120 min)) respectively in lean mice. However, even the highest dose of PM1 did not alter normoglycemic condition. PM1 at dose of 100 mg/kg/day, i.p. for 28 days produced significant (p<0.05) reduction in body weight, plasma glucose (PG), triglycerides (TG) and total cholesterol (TC) content in high-fat streptozotocin-induced diabetic mice. PM1 also improved oral glucose tolerance significantly (p<0.05) with mean percentage reduction of 48.0% in glucose excursion (AUC(0-120 min)) and significantly (p<0.05) enhanced the endogenous antioxidant status in mice liver compared to diabetic control. PM1 preserved islet architecture and prevented hypertrophy of hepatocytes as evident from the histopathology of pancreas and liver. PM1 did not show any detectable hematological toxicity at therapeutic doses. In conclusion, PM1 exhibits antidiabetic effect possibly by inhibiting DPP-IV and improving antioxidant levels in high fat diet/streptozotocin (HFD/STZ) diabetic mice., (Copyright © 2010 Elsevier GmbH. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
406. This is when it happens.
- Author
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Kirk ST
- Subjects
- Anecdotes as Topic, Empathy, Humans, Attitude of Health Personnel, Attitude to Death, Professional-Patient Relations, Terminal Care
- Published
- 2009
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