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Handbook of Phytochemical Constituents of GRAS Herbs and Other Economic Plants
Published in James A. Duke, Handbook of Phytochemical Constituents of GRAS Herbs and Other Economic Plants, 2017
“Condurango”BETA-AMYRINCINNAMATE BK HHBCAOUTCHOUC 60,000 LX CRCCONDURANGAMINES PL JSGCONDURANGIN 10,000–20,000 BK HHBCONDURANGOGLYCOSIDE BK HHBCONDURITOL 5,000 BK HHBD-CYMAROSE BK HHBDEHYDRODREVOGENIN-D BK HHBDREVOGENIN-D BK HHBEO 100 PL 411/D-GLUCOSE BK HHBSITOSTEROL BK HHBTANNIN PL CRCD-THEVETOSE BK HHB
Metabolic Approach to Transdermal Drug Delivery
Published in Richard H. Guy, Jonathan Hadgraft, Transdermal Drug Delivery, 2002
Peter M. Elias, Kenneth R. Feingold, Janice Tsai, Carl Thornfeldt, Gopinathan Menon
The most compelling direct evidence for the central role of ECP in barrier formation comes from studies on glucosylceramide-to-ceramide processing. As with other lipid hydrolases, β-glucocerebrosidase β-GlcCer’ase) is concentrated in the outer epidermis, the highest levels being in the SC (31), where it is localized to membrane domains. In contrast, endogenous β-glycosidase activity is low in the SC of mucosal epithelia (32), which is up to an order of magnitude more permeable than epidermis. Moreover, glycosylceramides [type(s) unspecified] predominate over ceramides; untransformed LB contents persist into the outer SC, i.e., mature lamellar membrane structures do not form in mucosal epithelia. Recently, these correlative observations have been supported by direct evidence for the role of β-GlcCer’ase in the ECP of glucosylceramides-to-ceramides: (a) applications of specific conduritol-type inhibitors of β-GlcCer’ase both delay barrier recovery after acute perturbations and produce a progressive abnormality in barrier function when applied to intact skin (33). (b) In a transgenic murine model of Gaucher disease (GD), produced by targeted disruption of the β-GlcCer’ase gene, homozygous animals are born with an ichthyosiform dermatosis and a severe barrier abnormality (34). (c) In the severe type 2 neuronopathic form of GD, infants present with a similar clinical phenotype, including an ichthyosiform erythroderma (35). In all three situations (inhibitor, transgenic murine, type 2 GD), the functional barrier deficit is accompanied by an accumulation of glucosylceramides and the persistence of immature LB-derived membrane structures within the SC interstices. Together, these studies point to a critical role for glucosylceramide-to-ceramide processing in barrier homeostasis.
Evaluation of a flavonoids library for inhibition of pancreatic α-amylase towards a structure–activity relationship
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Carina Proença, Marisa Freitas, Daniela Ribeiro, Sara M. Tomé, Eduardo F. T. Oliveira, Matilde F. Viegas, Alberto N. Araújo, Maria J. Ramos, Artur M. S. Silva, Pedro A. Fernandes, Eduarda Fernandes
Acarbose is a pseudotetrasaccharide produced by Actinoplanes sp. fermentation and its structure comprises a hydroxymethyl conduritol residue α-(1,4) linked to a 4-amino-4,6-dideoxyglucose which is, in turn, α-(1,4) linked to maltose52,53. It is the most widely prescribed α-glucosidase and α-amylase inhibitor. However, it was previously shown that only a mild inhibition of pancreatic α-amylase is recommended in order to avoid gastrointestinal side-effects as a result of excessive bacterial fermentation of carbohydrates in colon11, that has been shown as a limiting factor for T2DM treatment, in some countries11. In the present work, the IC50 values found for the tested flavonoids were higher than the IC50 value found for acarbose, which is 1.3 ± 0.2 µM. The mild pancreatic α-amylase inhibition prevents the abnormal bacterial fermentation of carbohydrates in the colon and consequent gastrointestinal adverse effects, such as abdominal distention, flatulence and diarrhea11. Moreover, it was previously shown by our research group that, in general, the tested flavonoids were more effective concerning the inhibition of α-glucosidase than the inhibition of α-amylase15. As such, the obtained results suggest that flavonoids could be promising α-amylase inhibitors and cause less gastrointestinal side-effects. Interestingly, it was found that the combination of baicalein or apigenin with acarbose showed additive inhibition of α-amylase at lower concentrations and antagonistic inhibition at higher concentrations. On the other hand, the combination of baicalein with acarbose synergistically inhibits α-glucosidase and lowers HGPP54.