Ethanol Absorption Research Articles

Alcohol-related diseases: from metabolism to the main effect on the body.

Alcohol consumption can cause, beyond addiction, roughly 200 different diseases and at least fourteen types of cancer. In 2016 the WHO estimated that 29% of alcohol-related deaths were mainly due to oncological diseases, liver cirrhosis (20%), and cardiovascular disorders (19%). The aim of this review was to focus on the absorption and metabolism of ethanol and discuss the main conditions caused by alcohol consumption (i.e., liver and cardiovascular diseases, and tumors). This narrative review is based on a detailed analysis of the scientific literature published before January 31, 2024 (PubMed, Web of Science, Scopus, Google Scholar). Approximately 90% of the absorbed alcohol reaches the liver where it is metabolized to acetaldehyde, a highly reactive and toxic compound. The excessive use of alcohol causes damage to several organs and systems, mainly the liver (e.g., steatosis, steato-hepatitis, fibrosis, and cirrhosis), cardiovascular system (cardiomyopathy, arrythmias, arterial hypertension, and stroke), and significantly contribute to the onset of neoplastic lesions to various organs including the esophagus, liver and breast. Even moderate drinking appears not to reduce mortality risk. Alcohol intake is one of the main risk factors for several pathological conditions and social problems, thus drastically impacting on public health. Proper awareness of the high risk related to alcohol consumption is of crucial importance to reduce the harm to public health.

Concentration- and time-dependent behavioural effects of ethanol on Lumbriculus variegatus.

Ethanol is one of the most widely used drugs in the world. Ethanol induces profound physiological and behavioural responses in invertebrate model organisms, such as Caenorhabditis elegans and Drosophila melanogaster. Lumbriculus variegatus (Annelida, Oligochaete) is an aquatic worm which shows behavioural responses to common drugs and thus is potentially useful in pharmacological research. The effects of ethanol are unknown in this organism. In this study, we examine the effects of acute exposure to ethanol (0-500 mM) on the stereotypical movements and locomotor activity of L. variegatus and examine the concentration- (0-500 mM) and time-dependent (0-210 min) effects of ethanol in L. variegatus. We show that ≥250 mM ethanol reversibly reduced the ability of tactile stimulation to elicit stereotypical movements, namely body reversal and helical swimming and locomotor activity (p < 0.05, N = 8). We also found that 2 min of exposure to ≥250 mM ethanol rapidly induces steady-state hypokinesis (p < 0.05, N = 11) and confirm ethanol absorption into L. variegatus tissues. Additionally, we also observed acute ethanol tolerance after 150 min of exposure to 500 mM ethanol (p < 0.05, N = 24). This study is the first to report the behavioural effects of ethanol in L. variegatus. Our results show that this is a model organism for use in ethanol studies, providing further evidence for its utility in pharmacological research.

Tunable Luminescence in LiSc1‐yGayW2O8:Cr3+ Phosphors for LED Applications

AbstractAchieving emission peaks in the near‐infrared II regions (NIR II) and tunable near‐infrared (NIR) emission is still a huge challenge in the development of NIR phosphors. Here, a series of LiSc1‐yGayW2O8:Cr3+ phosphors are reported based on crystal engineering, whose luminescence can be tuned from NIR‐II to NIR I. LiScW2O8:Cr3+ possesses an ultra‐wide emission in the range of 850–1400 nm with peak at 1069 nm and a full width at half maximum (FWHM) of 225 nm and the main emission light is located in the NIR‐II region. Introducing Ga3+ into LiScW2O8:Cr3+ to form LiSc1‐yGayW2O8:Cr3+, the emission spectrum is blueshifted, which better aligns with the characteristic absorption lines of most functional groups. Additionally, the intensity of emission and thermal stability are also improved. The NIR phosphor‐converted light‐emitting diodes (pc‐LED) device is prepared by using the optimized LiSc0.5Ga0.5W2O8:0.12Cr3+ phosphor and green chip, and different characteristic absorptions are detected by measuring the NIR absorption of water and ethanol with the prepared pc‐LED as a radiation source. These results indicate that the ultra‐wide near‐infrared luminescence of LiSc1‐yGayW2O8:xCr3+ holds potential for applications in non‐destructive analysis.

In Vitro Activity of Ethanol Extract of Rimbang Fruit (Solanum ferox) as an Active Ingredient in Sunscreen Preparations

Solanum ferox is a typical Central Kalimantan plant widely used by Dayak’s community as a vegetable. The study aims to determine the ethanol extract of sour eggplant activities by measuring its SPF in vitro and identifying secondary metabolite contents. The sour eggplant is extracted by maceration using 96% ethanol solvent and then bound with an evaporator. The secondary metabolite groups of ethanol extract were identified using phytochemical screening. The identification results indicate the presence of flavonoid, terpenoid, steroid, and phenolic compounds. Then, the ethanol extract was fractionated with a water solvent, and its functional cluster was identified using the IR spectrum. IR spectral identification results indicate the presence of OH, C-O, C=C olefin, C -O ether, and aliphatic CH functional groups. (CH2 and CH3) SPF values were determined by measuring the absorption of ethanol and water extracts in vitro using UV-Vis spectrophotometry at UV-B wavelengths of 290-320 nm. In vitro testing has been conducted as a preliminary test in developing a sunscreen product (active substance). The SPF values of ethanol extract and water from weighted fruit extract in sequence are 40 and 23 at a 10% concentration with ultra-category.

Effectiveness of Administering Red Belt Leaf Extract (Piper Crocatum) Against Aeromonas Hydrophila Bacteria in Vitro

Diseases caused by pathogenic bacteria such as Aeromonas hydrophila are a major health concern. However, the use of red betel leaves (P. crocatum) can serve as a potential solution to this problem due to their antibacterial properties. This research aimed to study the antibacterial activity of red betel leaf extract (P. crocatum), the structure and character of the bacteria inhibited by the extract, and the bioactive components present in the leaves. The results of the disc test showed that the average zone of inhibition was 14.28 mm, while the MIC test results revealed that a dose of 100 mg/L could inhibit bacterial growth (bacteriostatic). Moreover, the crude extract of red betel leaf (P. crocatum) damaged the cell walls and cell membranes of A. hydrophila bacteria, thereby affecting their character and structure. The UV-VIS analysis of red betel leaf extract (P. crocatum) and FTIR analysis with 96% ethanol absorption indicated the presence of flavonoids, saponins, tannins, and alkaloids. These findings suggest that red betel leaves can be used as a natural remedy to fight bacterial infections caused by pathogenic bacteria such as Aeromonas hydrophila

Ethanol-based solubility-enabling oral drug formulation development: Accounting for the solubility-permeability interplay

The aim of the current work was to investigate the key factors that govern the success/failure of an ethanol-based solubility-enabling oral drug formulation, including the effects of the ethanol on the solubility of the drug, the permeability across the intestinal membrane, the drug's dissolution in the aqueous milieu of the gastrointestinal tract (GIT), and the resulting solubility-permeability interplay. The concentration-dependent effects of ethanol-based vehicles on the solubility, the in-vitro Caco-2 permeability, the in-vivo rat permeability, and the biorelevant dissolution of the BCS class II antiepileptic drug carbamazepine were studied, and a predictive model describing the solubility-permeability relationship was developed. Significant concentration-dependent solubility increase of CBZ was obtained with increasing ethanol levels, that was accompanied by permeability decrease, both in Caco-2 and in rat perfusion studies, demonstrating a tradeoff between the increased solubility afforded by the ethanol and a concomitant permeability decrease. When ethanol absorption was accounted for, an excellent agreement was achieved between the predicted permeability and the experimental data. Biorelevant dissolution studies revealed that minimal ethanol levels of 30 % and 50 % were needed to fully dissolve 1 and 5 mg CBZ dose respectively, with no drug precipitation.In conclusion, key factors to be accounted for when developing ethanol-based formulation include the drug's solubility, permeability, the solubility-permeability interplay, and the drug dose intended to be delivered. Only the minimal amount of ethanol sufficient to solubilize the drug dose throughout the GIT should be used, and not more than that, to avoid unnecessarily permeability loss, and to maximize overall drug absorption.

Medical associations and expert committees urge that ethanol be approved as a virucidal active substance for use in hand antiseptics under the European Biocidal Products Regulation, without a CMR classification.

Since 2007, the classification of ethanol under the Biocidal Products Regulation has paradoxically remained unresolved due to conflicting views among experts and authorities. Initially, there was a discussion about classifying ethanol as carcinogenic. The current proposal to extend its harmonized classification includes, among other things, categorizing it as reproductive toxicity category 2 ("suspected to have CMR potential for humans"; carcinogenic, mutagenic, reprotoxic). If ethanol were classified under reproductive toxicity category 2, it would mean that the only active ingredient in hand antiseptics effective against non-enveloped viruses would no longer be available. Available epidemiological studies do not confirm an increased risk for cancer from EBHR in exposed individuals, except under uncommon or unlikely routes or levels of exposure.The evidence for ethanol's reprotoxic effect originates from the consumption of alcoholic beverages by pregnant women, where ethanol uptake is incomparably higher. The amount of transdermal ethanol absorption during hand antisepsis is up to ten times lower than the oral intake of beverages containing hidden ethanol, such as apple juice, kefir, or non-alcoholic beer. Blood alcohol levels after using EBHR remain within the physiological range associated with food intake. There is no epidemiological evidence of toxicity for workers handling ethanol-containing products in industry or using EBHR in healthcare settings. Given that the classification of EBHR as reproductive toxicity category 2 is not supported by current scientific research and that no alternative biocidal active substance in hand rubs is effective against non-enveloped viruses, medical associations and expert committees from Europe, the USA, Canada, the Asia-Pacific region, and the World Society for Virology unequivocally recommend, with the highest priority, that EBHR be approved as an active substance for PT1 biocides and not be classified as a reproductive toxicant in category 2.

PNIPAM Brushes in Colloidal Photonic Crystals Enable Ex Situ Ethanol Vapor Sensing.

Structural colors are formed by the periodic repetition of nanostructures in a material. Upon reversibly tuning the size or optical properties of the repetitive unit inside a nanostructured material, responsive materials can be made that change color due to external stimuli. This paper presents a simple method to obtain films of ethanol vapor-responsive structural colors based on stacked poly(N-isopropylacrylamide) (PNIPAM)-grafted silica nanoparticles. Our materials show clear, reversible color transitions in the presence of near-saturated ethanol vapor. Moreover, due to the absorption of ethanol in the PNIPAM brushes, relatively long recovery times are observed (∼30 s). Materials based on bare or poly(methyl methacrylate) (PMMA) brush-grafted silica nanoparticles also change color in the presence of ethanol vapor but possess significantly shorter recovery times (∼1 s). Atomic force microscopy reveals that the delayed recovery originates from the ability of PNIPAM brushes to swell in ethanol vapor. This renders the films highly suitable for ex situ ethanol vapor sensing.

Preparation of Dihydromyricetin-Loaded Self-Emulsifying Drug Delivery System and Its Anti-Alcoholism Effect.

Intraperitoneal injection of dihydromyricetin (DMY) has shown promising potential in the treatment of alcoholism. However, its therapeutic effect is limited due to its low solubility, poor stability, and high gut-liver first-pass metabolism, resulting in very low oral bioavailability. In this study, we developed a DMY-loaded self-emulsifying drug delivery system (DMY-SEDDS) to enhance the oral bioavailability and anti-alcoholism effect of DMY. DMY-SEDDS improved the oral absorption of DMY by facilitating lymphatic transport. The area under the concentration-time curve (AUC) of DMY in the DMY-SEDDS group was 4.13-fold higher than in the DMY suspension group. Furthermore, treatment with DMY-SEDDS significantly enhanced the activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) in the liver of mice (p < 0.05). Interestingly, DMY-SEDDS also increased ADH activity in the stomach of mice with alcoholism (p < 0.01), thereby enhancing ethanol metabolism in the gastrointestinal tract and reducing ethanol absorption into the bloodstream. As a result, the blood alcohol concentration of mice with alcoholism was significantly decreased after DMY-SEDDS treatment (p < 0.01). In the acute alcoholism mice model, compared to saline treatment, DMY-SEDDS prolonged the onset of LORR (loss of righting reflex) (p < 0.05) and significantly shortened the duration of LORR (p < 0.01). Additionally, DMY-SEDDS treatment significantly reduced gastric injury in acute alcoholism mice. Collectively, these findings demonstrate the potential of DMY-SEDDS as a treatment in the treatment of alcoholism.

Detoxification activity of bioactive food compounds against ethanol-induced injuries and hangover symptoms: A review.

Alcohol drinking is a popular activity among adolescents in many countries, largely due to its pleasant, relaxing effects. As a major concern, ethanol consumption put the drinkers at risk of nutrients' deficiency due to the disordered eating, anorexia, and malabsorption of nutrients. Moreover, alcohol drinking may lead to the development of hangover symptoms including diarrhea, thirsty, fatigue, and oxidative stress. A broad range of functional food components with antioxidant and/or anti-inflammatory properties including pectin, aloe vera polysaccharides, chito-oligosaccharides, and other herbal components have been explored due to their detoxification effects against ethanol. The underlying anti-hangover mechanisms include reducing the intestinal absorption of ethanol or its metabolites, increasing the activity of ethanol metabolizing enzymes, development of fatty acid β-oxidation in mitochondria, inhibition of inflammatory response, blocking the target receptors of ethanol in the body, and possession of antioxidant activity under the oxidative stress developed by ethanol consumption. Therefore, the development of bioactive food-based therapeutic formula can assist clinicians and also drinkers in the alleviation of alcohol side effects.

The comparative and correlation study of postmortem ethanol levels between axillosubclavian blood and femoral venous blood in forensic autopsy cases at Thammasat University Hospital, Thailand

BackgroundFemoral venous blood (FVB) is accepted as a standard sample for postmortem ethanol analysis, but owing to the nature of unnatural death cases, FVB may not always be obtainable, and subclavian blood might be used for alternative specimens. This study investigated the correlation between postmortem ethanol concentrations in FVB and axillosubclavian blood (ASB) from autopsy cases in the tropical climate of Central Thailand. Two other factors potentially affecting the correlation, the time of death and ethanol absorption state, were also investigated. FVB, ASB, and vitreous humor were collected from 100 subjects between May 2021 and May 2022. Subjects with decomposition signs and large open wounds were excluded. ASB was drawn from the axillosubclavian vein at the thoracic outlet. Ethanol concentrations in all samples were measured by headspace GC-FID.ResultsEthanol concentrations in ASB were statistically identical to those in FVB (p = 0.6761) and their relationship was statistically correlated (r = 0.9818, p < 0.001). The correlation was not statistically influenced by time since death or absorptive statuses. The diagnostic study to assess the practical application of ASB instead of FVB at a cut-off concentration above 50 mg/dL yielded an area under the ROC curve of 0.96.ConclusionsOur study indicated that ASB can be used as an alternative specimen for postmortem ethanol analysis when FVB is unavailable in dead bodies that are in a tropical climate.

An orally delivered bacteria‐based coacervate antidote for alcohol detoxification

Alcohol intoxication causes serious diseases, whereas current treatments are mostly supportive and unable to convert alcohol into nontoxic products in the digestive tract. To address this issue, an oral intestinal-coating coacervate antidote containing acetic acid bacteria (AAB) and sodium alginate (SA) mixture was constructed. After oral administration, SA reduces absorption of ethanol and promotes the proliferation of AAB, and AAB converts ethanol to acetic acid or carbon dioxide and water by two sequential catalytic reactions in the presence of membrane-bound alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). In vivo study shows that the bacteria‐based coacervate antidote can significantly reduce the blood alcohol concentration (BAC) and effectively alleviates alcoholic liver injury in mice. Given the convenience and effectiveness of oral administration, AAB/SA can be used as a promising candidate antidote for relieving alcohol-induced acute liver injury.

Bamboo-derived hydrophobic porous graphitized carbon for adsorption of volatile organic compounds

Biomass-derived activated carbons (BACs) are often used as green adsorbents for the removal of VOCs, however, their abundant surface functional groups severely reduced their adsorption selectivity under humid conditions. In this study, hydrophobic bamboo-derived porous graphitized carbons (BPGCs) were prepared using a combined catalytic graphitization method. The optimal micro-mesoporous BPGC had a large specific surface area of 2181 m2/g and a low surface O/C ratio of 0.038. Under dry conditions, its adsorption capacities for toluene, cyclohexane and ethanol were 6.7, 3.8 and 2.4 mmol/g, respectively. At 80 % relative humidity, its adsorption capacities for toluene and cyclohexane remained 82 % and 66 %, while the uptake of ethanol even increased by 33 %. In the two-component adsorption test, BPGC showed a high selectivity for toluene adsorption over ethanol, with 198 times more toluene than ethanol. The adsorption mechanism at the microscopic molecular level was revealed by DFT calculation. The abundant π electrons and high polarizability of BPGC allow for strong π-π interactions and dispersion forces with non-polar organics, while the abundant oxygen-containing groups on BAC have strong adsorption force on water. The absorption of ethanol by capillary condensed water in mesopores of BPGC may contribute to its increased uptake under humid conditions. BPGC allowed for faster adsorption kinetics than activated carbon. More than 90 % of the adsorbed toluene was desorbed from BPGC at 90 °C. Owing to abundant renewable raw materials, excellent hydrophobicity and desirable textural properties, BPGCs may be promising adsorbents.

AP-XPS Study of Ethanol Adsorption on Rutile TiO2(110)

The photoactivity of rutile TiO2(110) renders its surfaces of particular interest for the study of surface reactions. In particular, rutile TiO2(110) surfaces are active for hydrogen production, both via the water splitting process and via ethanol degradation under ultraviolet illumination. The selective photocatalytic dehydrogenation of rutile TiO2(110) is not fully understood yet, and an important question in this context is how ethanol adsorbs onto the rutile TiO2(110) surface under ambient conditions. Here, we present the first in situ experimental study on the absorption of ethanol on rutile TiO2(110) at room temperature and near-ambient conditions. The surface sensitivity of synchrotron-based ambient pressure X-ray photoelectron spectroscopy allows for an in-depth analysis of the surface species (molecular ethanol and ethoxies) and their coverage as well as an estimation of the energy difference between the two species. Through modeling of the O 1s core level and comparison to experimental results we show that both molecular and dissociative adsorption of ethanol occurs. The difference in adsorption energy range calculated from modeling of the O 1s core level was 0.018–0.033 eV, with dissociative adsorption the most energetically favorable. The difference in adsorption energy is almost an order of magnitude lower than previous estimations from theoretical calculations. In addition, we show that at room temperature a multilayer is formed with increasing pressure of ethanol.

Effect of post-processing conditions on polyacrylate materials used in stereolithography

Additive manufacturing offers simple and cost-effective production of highly customizable 3D-components. One particularly interesting technology is stereolithography (SLA), which enables the fabrication of micro- and milliscale reactionware using transparent materials. In this work, the influence of 3D-printing settings such as printing angle and layer thickness and post-processing conditions, as well as the size and shape of the test samples, on the mechanical, thermal and physico-chemical properties is determined. Two photocurable acrylate resins were used for 3D-printing: Clear and High Temperature. Post-curing of the test samples was performed using several methods and varying treatment times. The tensile test results show that a higher degree of cure results in a higher tensile strength and smaller elongation. On the other hand, layer thickness and print angle have a stronger influence on the tensile strength than some of the post-curing methods. In particular, the samples printed at 45° angle with the smallest layer thickness of 25 µm were found to be the toughest. When comparing Clear and High Temperature material, it is found that the Clear samples can withstand higher stress and strain, but the samples made of High Temperature resin are more rigid and show higher Young's modulus. Differential scanning calorimerty (DSC) tests show that post-curing reduces curing enthalpy, while the glass transition temperature shifts to higher temperatures, indicating crosslinking of the polymer chains. The swelling test showed that both resins can be considered water resistant with an absorption of less than 2% within 24 h. Regarding ethanol and acetone, High Temperature resin proved to be more resistant compared to the Clear resin. The samples post-cured in the SunTest chamber also showed much lower absorption of ethanol and acetone. The contact angle measurement shows that all samples are hydrophilic, regardless of the degree of post-curing or the printing angle.

Understanding the impact of convective ethanol humidity on the precipitation behaviour of dissolved lactose in a water droplet

• Crystallization behaviour during ethanol-vapour precipitation drying was studied. • Internal composition profiles of lactose-containing droplets were investigated. • High ethanol humidity promotes the formation of dendritic crystallites. • Nonuniform droplet shrinkage is due to randomly packed structures. Crystalline lactose particles, composed of agglomerated ultrafine crystallites, were produced using the antisolvent vapour precipitation technique. This technique exposes a single suspended aqueous lactose droplet to a convective stream laden with ethanol vapour. Manipulating simultaneous ethanol absorption and water evaporation from the droplet by adjusting the ethanol vapour humidity, led to various crystallite morphologies. Within the intermediate and high ranges of the ethanol humidity tested, higher humidity led to finer and more dendritic-like crystallites. Surprisingly, low ethanol humidity (20% ERH) led to a relatively high rate of ethanol concentration increment in the droplet but inadvertently exhibited a low nucleation potential. Thus, the crystallization potential of a lactose droplet under antisolvent vapour precipitation conditions will need to be evaluated in terms of the rate of ethanol concentration increment as well as the solute concentration-ethanol concentration history. These factors will be important in controlling or scaling up the antisolvent vapour precipitation technique.

Low-lying electronic states of ethanol investigated by theoretical and synchrotron radiation methods

We investigate the ethanol absorption spectrum in the range 5.64–10.78 eV (220–115 nm), by combining ab initio theoretical and experimental methods in order to provide the most accurate and up-to-date information about the electronic state spectroscopy of ethanol. In particular, absolute cross-section values are reported from high-resolution vacuum ultraviolet (VUV) photoabsorption measurements. The present VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the Rydberg (ndσ, ndσ′ ← (3a′′/13a)), n ≥ 3 members of the Rydberg (ndπ′(a′) ← (3a′′/13a)) and n = 3 members of the Rydberg (npσ′ ← (10a′/12a)) transitions. The experimental absolute photoabsorption cross sections have subsequently been used to calculate the photolysis lifetime of ethanol in the Earth's atmosphere (0–50 km), showing that solar photolysis is expected to be a weak sink at altitudes lower than 40 km to ●OH radical reactions. Potential energy curves for the lowest-lying excited electronic states, as a function of the O–H and the C–OH coordinates, are also obtained employing the equation of motion coupled cluster single and doubles (EOM-CCSD) and time dependant density functional theory (TD-DFT) methods. These show clear dissociation character at inter-nuclear distances greater than 2.0 Å for the RO–H and 2.2 Å for the RC–OH bond lengths, indicating the rather complex multidimensional character of the potential energy surfaces involved.

Characterization techniques comparison towards a better understanding of different cork-based stoppers types

The study aimed to evaluate the use of conventionally-applied techniques for biopolymer characterization to improve the knowledge about the properties of five different commercial cork-based stoppers types. Although low porosities were observed (max. value of 23%), for some samples the technique applied to obtain the density promoted significant changes in this property. The stoppers presented low water (WAC) and wine absorption capacities (WIAC) (max. values of 34% and 27% after 24 h, respectively), confirming cork's hydrophobicity. In general, ethanol absorption capacity was higher than WAC and WIAC. Micrographs showed that the agglomeration process used to format micro-agglomerated, silktop 1 + 1, and champagne stoppers can deform but not disrupt the cells, confirming cork's suitability to be used in stoppers' development. Besides that, agglomeration was responsible for increasing the flexibility of the stoppers, once micro-agglomerated samples presented the lowest elastic modulus (17.6 MPa); cork's thermal stability can be linked to chemical composition.

Methodological Approach to the Elaboration of the Analytical Procedure of the Antioxidant Activity Determination of the Schisandra chinensis (Turcz) Baill. Extracts

The DPPH assay provides an easy and rapid way to evaluate the antioxidant activity of herbal preparations. The most important stage of the elaboration of the analytical procedure of total antioxidant activity measured by the DPPH test is to select the volume of an extract or its appropriate dilution for the determination of the reliable total antioxidant activity of the extract. If the concentration of antioxidants is too high in an extract, the kinetic curves of antioxidant activity changes on time are more parallel to axis X (time) and what is more, the total antioxidant activity does not depend on the volume of the extract. The analytical procedure of the antioxidant activity determination of the Schisandra chinensis (Turcz) Bail. extracts was elaborated, namely a volume and dilution of the extract was selected, rutin was chosen for the calibration curve. The calibration curve was plotted in the concentration range of 95–305 mg/L (y=0.228x+7.0992, R²=0.9945). The results suggest that the leaves of S. chinensis are a valuable source of antioxidant compounds with significant antioxidant activity. The antioxidant activity was evaluated by the DPPH test. It was equal to 227.2–443.6 mg/L in the extracts or 1.14–2.22 mg/g in the leaves of rutin-equivalents depending on the particle size. Additionally, it was established that particle size in the range of 2 to 3 mm was optimal for the preparation of Schisandra chinensis extracts as the antioxidant activity was the highest. The ethanol absorption coefficient is a main technological parameter in the pharmaceutical manufacture of extracts. The absorption coefficient of the Schisandra chinensis leaves for 70 % ethanol was in the range of 3.4 to 6.5 ml/g and depended on the particle size.

Selection pressure at altitude for genes related to alcohol metabolism: A role for endogenous enteric ethanol synthesis?

What is the topic of this review? Highland natives have undergone natural selection for genetic variants advantageous in adaptation to the hypobaric hypoxia experienced at high altitude. Why genes related to alcohol metabolism appear consistently selected for has not been greatly considered. We hypothesize that altitude-related changes in the gut microbiome offer one possible explanation. What advances does it highlight? Low intestinal oxygen tension might favour the production of ethanol through anaerobic fermentation by the gut microbiome. Subsequent increases in endogenous ethanol absorption could therefore provide a selection pressure for gene variants favouring its increased degradation, or perhaps reduced degradation if endogenously synthesized ethanol acts as a metabolic signalling molecule. Reduced tissue availability of oxygen results from ascent to high altitude, where atmospheric pressure, and thus the partial pressure of inspired oxygen, fall (hypobaric hypoxia). In humans, adaptation to such hypoxia is necessary for survival. These functional changes remain incompletely characterized, although metabolic adaptation (rather than simple increases in convective oxygen delivery) appears to play a fundamental role. Those populations that have remained native to high altitude have undergone natural selection for genetic variants associated with advantageous phenotypic traits. Interestingly, a consistent genetic signal has implicated alcohol metabolism in the human adaptive response to hypobaric hypoxia. The reasons for this remain unclear. One possibility is that increased alcohol synthesis occurs through fermentation by gut bacteria in response to enteric hypoxia. There is growing evidence that anaerobes capable of producing ethanol become increasingly prevalent with high-altitude exposure. We hypothesize that: (1) ascent to high altitude renders the gut luminal environment increasingly hypoxic, favouring (2) an increase in the population of enteric fermenting anaerobes, hence (3) the synthesis of alcohol which, through systemic absorption, leads to (4) selection pressure on genes relating to alcohol metabolism. In theory, alcohol could be viewed as a toxic product, leading to selection of gene variants favouring its metabolism. On the contrary, alcohol is a metabolic substrate that might be beneficial. This mechanism could also account for some of the interindividual differences of lowlanders in acclimatization to altitude. Future research should be aimed at determining any shifts to favour ethanol-producing anaerobes after ascent to altitude.