Innovative Approach to Enhance Bioavailability of Birch Bark Extracts: Novel Method of Oleogel Development Contrasted with Other Dispersed Systems

Birch outer bark extract (BBE), containing pentacyclic triterpenes such as betulin, lupeol, and betulinic acid, is a widely recognized natural product renowned for its diverse pharmacological effects. However, its limited water solubility restricts its bioavailability. Therefore, the main objective is to enhance the bioavailability of BBE for pharmaceutical use. In this study, we aimed to develop a dispersion system utilizing a unique oleogel-producing method through the recrystallization of BBE from an ethanol solution in the oil phase. We generated an oleogel that demonstrates a notable 42-80-fold improvement in betulin and lupeol peroral bioavailability from BBE in Wistar rats, respectively. A physical paste-like BBE hydrogel developed with antisolvent precipitation showed a 16-56-fold increase in the bioavailability of betulin and lupeol from BBE in rat blood plasma, respectively. We also observed that the repeated administration of the BBE oleogel did not exhibit any toxicity at the tested dose (38.5 mg/kg betulin, 5.2 mg/kg lupeol, 1.5 mg/kg betulinic acid daily for 7 days). Betulin and betulinic acid were not detected in rat heart, liver, kidney, or brain tissues after the peroral administration of the oleogel daily for 7 days. Lupeol was found in rat heart, liver, and kidney tissues.

Evaluation of Oleogels Stabilized by Particles of Birch Outer Bark Extract through a Novel Approach

Structuring liquid oils into oleogels using natural and abundant biomass components as gelling agents is of great significance in fields such as foods, pharmaceuticals, and cosmetics. In this work, a more energy-efficient and technologically simpler approach for directly preparing birch outer bark extract particles containing oleogel was used. This method involves introducing birch outer bark extract particles into the oil phase directly from the extract solution, combining both the evaporation of solution and gel formation. As a result, stable oleogels of various vegetable oils (sunflower, almond, olive, and hemp seed) were obtained with birch outer bark extract particle contents of 4-10%. Infrared spectroscopy and particle size analysis confirmed that when increasing the content of extract particles in the oil, increasing self-assembly of extract particles via hydrogen bonding occurs, leading to the formation of a more structured network. This is consistent with gel strength values from rheological tests of oleogels, which also increased with particle concentration. The obtained oleogels showed important properties such as good tolerance to time-dependent deformation, shear thinning, and thermoreversibility.

Effect of Betulin Colloidal Particles on Proliferation and Cytokine Secretion of Human Skin Fibroblasts

The aim of the study was to obtain untreated and treated betulin colloidal particles and assess their effect on the viability, morphology, proliferation and cytokine secretion of human dermal fibroblasts. To improve bioavailability, betulin treatment was performed by an antisolvent precipitation technique. The average particle size after treatment in the aqueous dispersion decreased from 552.9 ± 11.3 to 278.2 ± 1.6 nm. Treated betulin colloidal particles showed no cytotoxicity up to a concentration of 400 µg·mL-1 in the colorimetric tetrazolium salt viability test (CCK-8). Moreover, the cell morphology was not changed in the presence of betulin colloidal particles at a concentration range from 0.78 to 400 µg·mL-1. The obtained results also show that betulin particles induce the secretion of the proinflammatory and angiogenesis-stimulating cytokine IL-8. However, further studies would be required to clarify the mechanism of IL-8 secretion induction.

Semantic text mining in early drug discovery for type 2 diabetes

Background

Surveying the scientific literature is an important part of early drug discovery; and with the ever-increasing amount of biomedical publications it is imperative to focus on the most interesting articles. Here we present a project that highlights new understanding (e.g. recently discovered modes of action) and identifies potential drug targets, via a novel, data-driven text mining approach to score type 2 diabetes (T2D) relevance. We focused on monitoring trends and jumps in T2D relevance to help us be timely informed of important breakthroughs.

Methods

We extracted over 7 million n-grams from PubMed abstracts and then clustered around 240,000 linked to T2D into almost 50,000 T2D relevant ‘semantic concepts’. To score papers, we weighted the concepts based on co-mentioning with core T2D proteins. A protein’s T2D relevance was determined by combining the scores of the papers mentioning it in the five preceding years. Each week all proteins were ranked according to their T2D relevance. Furthermore, the historical distribution of changes in rank from one week to the next was used to calculate the significance of a change in rank by T2D relevance for each protein.

Results

We show that T2D relevant papers, even those not mentioning T2D explicitly, were prioritised by relevant semantic concepts. Well known T2D proteins were therefore enriched among the top scoring proteins. Our ‘high jumpers’ identified important past developments in the apprehension of how certain key proteins relate to T2D, indicating that our method will make us aware of future breakthroughs. In summary, this project facilitated keeping up with current T2D research by repeatedly providing short lists of potential novel targets into our early drug discovery pipeline.

Survival and breeding interval of an endangered marine vertebrate, the leatherback turtle Dermochelys coriacea, in French Guiana

In the context of global change, endangered species such as sea turtles undergo strong population dynamics changes. Understanding demographic processes inducing such changes is critical for developing appropriate measures for conservation and management. Nesting females of the French Guiana population of leatherback sea turtles Dermochelys coriacea represented 40% of the world’s total in 2001; today, they represent only 10%. Here, we analyze data from the long-term monitoring program of leatherbacks in French Guiana, based on 28 yr of capture-mark-recapture data from 46051 individuals in northwestern French Guiana. We used multievent models (multistate capture-recapture models with state uncertainty) to represent the main peculiarity of the life cycle, intermittent reproduction, and to take advantage of the use of several different types of marks to account for mark loss and incomplete detection. The average annual adult survival probability (mean ± SE) 0.789 ± 0.009 is low compared to published estimates for this species. By combining the estimates of departure and return probabilities, we provide an estimate of the interval among laying seasons equal to 2.777 ± 0.118 yr, which matches previous findings. Taking survival into account, this interval translates into an average of 1.704 ± 0.034 further reproductive seasons for an adult female having just bred, which is remarkably low compared to other long-lived vertebrates. The representation of the life cycle and mark loss in our models provides a sound structure for broader and richer analyses to extract biological information from marked individuals and offers an invaluable source of demographic information on leatherbacks, a species for which only a small segment of the population is accessible to intermittent sampling.

Two families with hemoglobin Sogn, beta(A11)14 Leu----Arg, in Minnesota and Indiana: hematologic, functional, and biosynthetic features

Sogn hemoglobinopathy was identified in a young American woman and in a young American man of apparently unrelated families of Norwegian ancestry. Both persons were asymptomatic and without clinical or hematologic manifestations. Hemoglobin Sogn, beta(A11)14 Leu----Arg, is an unstable hemoglobin that may easily be mistaken for hemoglobin S, G, or D by alkaline hemoglobin electrophoresis. These are the first known instances of hemoglobin Sogn outside of Norway. Oxygen affinity is normal. Sogn hemoglobinopathy is an incidental finding that has no adverse implication for the health of heterozygotes.

Accuracy of C-peptide:insulin molar ratio as a measure of hepatic removal of insulin

We measured transhepatic C-peptide and insulin concentrations in plasma, and hepatic removal of insulin, to examine whether the practice of reporting the C-peptide:insulin molar ratio as a measure of the hepatic removal of insulin is valid. In anesthetized dogs (n = 6), during electromagnetic hepatic blood flow monitoring, endogenous insulin was suppressed with somatostatin, while equimolar proportions of porcine insulin and simian C-peptide (2.4 and 6.0 pmol/kg.min) were infused during two consecutive 45-min periods. Insulin reached steady state within 20 min (t1/2 = 4.5 min); however, C-peptide concentrations continued to rise (t1/2 V 12.5 min). The ratio decreased when the peptide infusion was changed to the higher rate and increased when it was stopped, reflecting the more rapid removal of insulin than of C-peptide. Hepatic removal of insulin remained constant during the two infusion periods (average 60% extraction) and never correlated with the changing molar ratios. Hepatic net flux of insulin correlated with the ratio (P less than 0.05) only while plasma insulin concentrations were rising during constant-rate infusion. We therefore conclude that the molar ratio is not a reliable measure of the hepatic removal of insulin during non-steady states of insulin or C-peptide.

Mechanisms of lidocaine kinetics in the isolated perfused rat liver. I. Effects of continuous infusion

The mechanisms of time-related reduction in lidocaine clearance were studied using a "one-pass" perfused rat liver system. Lidocaine was infused continuously for a period up to 150 min (concentration ranged from 9.6 to 278 microM). The time required for lidocaine to achieve steady state in the effluent ranged from 20 to 90 min. Analysis of material balance suggested that capacity-limited tissue binding was partially responsible for determining the time to steady state. The characteristic rise of monoethylglycinexylidide to a maximum within 5 min and decline to a stable level during constant lidocaine infusion suggested that the deethylation pathway may be partly deactivated. This observation could be the major determinant for the time-dependent effects of lidocaine elimination. Saturation of metabolism, mainly hydroxylation, and product inhibition by monoethylglycinexylidide did not reduce the extraction of lidocaine significantly. The dose-related reduction in lidocaine elimination is believed to have little contribution to the time effects of lidocaine.

Pharmacokinetic approach to the estimation of hepatic removal of insulin

We simultaneously measured hepatic insulin removal invasively and estimated hepatic clearance and extraction of insulin pharmacokinetically from cardiac output and peripheral plasma concentrations (relatively) noninvasively. The invasive methods involved continuous electromagnetic measurements of portal venous and hepatic arterial blood flow and simultaneous intermittent sampling of blood from the portal and hepatic veins and femoral artery for assay of insulin concentrations. The noninvasive method assumed that hepatic plasma flow is proportional to cardiac output and that hepatic clearance is a constant fraction of total body clearance of insulin. In anesthetized dogs (n = 6), endogenous insulin was suppressed with somatostatin (800 ng/kg/min) while biosynthetic human insulin (0.25, 0.50, and 1.00 mU/kg/min) was infused to steady state during three consecutive 90-min periods. Insulin concentrations were directly proportional to the infusion rate (p less than 0.01). Hepatic blood flow accounted for 20 +/- 2% of cardiac output. Measured hepatic clearance accounted for 51 +/- 5% of total body clearance of insulin and correlated with the pharmacokinetic estimates (p less than 0.01); the estimates of hepatic clearance ranged from 91 to 114% of the measured values. We conclude that this pharmacokinetic approach, which requires only samples of peripheral blood and estimates of hepatic blood flow, may be used to study the hepatic removal of insulin relatively noninvasively.

Rates of entry of alanine and glycerol and their contribution to glucose synthesis in fasted chickens

Rates of entry of alanine and glycerol and their contribution to glucose synthesis were studied in 48-h fasted White Leghorn cockerels using primed constant intravenous infusions of L-[U-14C]alanine and [U-14C]glycerol. Entry rates of alanine and glycerol were 112 and 401 mumol/h per kg body weight, respectively. Of the total glucose irreversible loss (entry rate), 1.5 and 6.6% were derived from alanine and glycerol, respectively. The possibilities of the operation of a glyoxylate cycle and omega-oxidation of fatty acids in the fasted chicken are discussed.

Rates of entry and oxidation of D(-)-3-hydroxybutyrate and glucose in fed and fasted chickens

Rates of entry and oxidation of D(-)-3-hydroxybutyrate (DBHB) and glucose and their contribution to the total metabolic production of CO2 were studied in fed and 48-hr fasted Leghorn roosters using primed constant intravenous infusions of NaH14CO3, D(-)-3-[3-14C]-hydroxybutyrate, and D-[U-14C] glucose. Fasting increased plasma DBHB concentrations sixfold but did not change plasma glucose levels. In both states of nutrition, rates of CO2 production were identical (P greater than .05). Mean fractions of the total CO2 derived from DBHB and glucose in fed and fasted chickens, respectively, were: DBHB, 1.7 and 9.9% (P less than .001); glucose, 29 and 10% (P less than .001). Entry rates of DBHB and glucose in fed chickens were 276 and 5936 mumoles/hr per kg (P less than .001), respectively, and in starved birds were 1703 and 2204 mumoles/hr per kg (P less than .001), respectively. Fasting increased the oxidation rate of DBHB from 124 to 737 mumoles/hr per kg (P less than .001) and decreased the oxidation rate of glucose from 1491 to 525 mumoles/hr per kg (P less than .001). During fasting, glucose homeostasis is maintained in part by concomitant decreases in glucose entry and oxidation rates. The results are discussed with reference to the sparing effect of DBHB on glucose oxidation.

How concentrate feeding affects glucoregulatory hormones in ruminants: implications in bovine ketosis

Twenty-four feedlot steers and four sheep were fed roughage or grain rations while three other sheep received intraduodenal infusions of amino acids, glucose, volatile fatty acids, and proteins to determine whether the release of plasma glucagon-like immunoreactivity is influenced by dietary factors and the composition of duodenal chyme. Plasma glucagon-like immunoreactivity rose in both cattle and sheep as the proportion of grain in their rations was increased. In response to intraduodenal infusions, only glucose stimulated glucagon-like immunoreactivity release. These experiments demonstrate that plasma glucagon-like immunoreactivity concentrations change in cattle and sheep in response to the amount of grain consumed and that glucagon-like immunoreactivity release is triggered by glucose in intestinal chyme.