Chemical composition and antibacterial and antioxidant activity of a citrus essential oil and its fractions

ABSTRACT Essential oils (EOs) from Citrus are the main by-product of Citrus-processing industries. In addition to food/beverage and cosmetic applications, citrus EOs could also potentially be used as an alternative to antibiotics in food-producing animals. A commercial citrus EO—Brazilian Orange Terpenes (BOT)—was fractionated by vacuum fractional distillation to separate BOT into various fractions: F1, F2, F3, and F4. Next, the chemical composition and biological activities of BOT and its fractions were characterized. Results showed the three first fractions had a high relative amount of limonene (≥10.86), even higher than the whole BOT. Conversely, F4 presented a larger relative amount of BOT’s minor compounds (carvone, cis-carveol, trans-carveol, cis-p-Mentha-2,8-dien-1-ol, and trans-p-Mentha-2,8-dien-1-ol) and a very low relative amount of limonene (0.08–0.13). Antibacterial activity results showed F4 was the only fraction exhibiting this activity, which was selective and higher activity on a pathogenic bacterium (E. coli) than on a beneficial bacterium (Lactobacillus sp.). However, F4 activity was lower than BOT. Similarly, F4 displayed the highest antioxidant activity among fractions (equivalent to BOT). These results indicated that probably those minor compounds that detected in F4 would be more involved in conferring the biological activities for this fraction and consequently for the whole BOT, instead of the major compound, limonene, playing this role exclusively

Chemical composition, antibacterial and antioxidant activities of a citrus essential oil and its fractions

The prohibition of antibiotic use in animal feed since 2006 by the European Community, due to the concern about the growing emergence of bacterial resistance, has led to the search for alternatives to substitute antibiotics. Essential oils (EOs) could be a possible alternative because of their antimicrobial properties. Specifically, citrus EOs, that are by-products of orange juice production, could be an excellent alternative since they have shown a good potential to fight pathogenic bacteria and their use in animal feed could become feasible since there is a high availability of them in the worldwide market. The aims of this study were to evaluate the chemical composition, antibacterial and antioxidant activities of a commercial citrus EO, Brazilian orange terpenes (BOT), and its fractions. Initially, the antibacterial activity of BOT was tested on Escherichia coli U21 (K88 LT/STb/F18/STa) isolated from pig gut and on Lactobacillus rhamnosus ATCC 7469 by a microdilution method. MIC and MBC results showed that E. coli (MIC=MBC=1.85 mg/mL) was more sensitive than L. rhamnosus (MIC=3.7 and MBC=7.4 mg/mL) to BOT, thus it displayed a selective antibacterial activity, affecting more the pathogenic than the beneficial bacteria. Limonene (78.7%) was determined as the major compound in BOT by GC-MS. After that, BOT was subjected to fractional distillation in a pilot system of continuous distillation. Four fractions were obtained: F1, F2, F3, and F4. The first three fractions were characterized by a high relative amount of limonene (86.9; 91.8; 91.9%,) followed by cis-limonene oxide, trans-limonene-oxide, and myrcene. Conversely, F4 was characterized by having the lowest amount of limonene (0.96%) and as having trans-carveol, carvone, cis-p-mentha-2,8-dien-1-ol, and trans-p-mentha-2,8-dien-1-ol as the major compounds. Only F4 was demonstrated to have an activity on E. coli (MIC=MBC=3.7 mg/mL) and L. rhamnosus (MIC=MBC=14.8 mg/mL). The F4 fraction also possessed the highest antioxidant activity (845.7 µmoltrolox/g - ORAC) in contrast to the others fractions (479.7; 334.4; 209.1 µmoltrolox/g, respectively), and even to the EO itself (785.1 µmoltrolox/g). The results imply that the minor compounds were responsible for the biological activity of this EO instead of its major compound limonene

Unraveling the selective antibacterial activity and chemical composition of citrus essential oils

ABSTRACT Post-weaning diarrhea (PWD) is an often disease affecting piglets. It is caused mainly by enterotoxigenic Escherichia coli (ETEC) colonization in pig gut. Antibiotics has been used to prevent, combat and control PWD and its negative impact on the productivity of pig breeding sector. Nonetheless, antibiotics due to their wide antibacterial spectrum also can reach beneficial gut bacteria, such as Lactobacillus. Lately, essential oils (EOs) have emerged as a potential alternative to using antibiotics in animal breeding because of their effect on bacterial growth. Commonly, citrus EOs are by-products of food industry and the availability of these EOs in the worldwide market is huge. Thus, six commercials citrus EOs were evaluated on ETEC strains, as model of pathogenic bacteria, and on Lactobacillus species, as models of beneficial bacteria. In overall, citrus EOs exhibited a selective antibacterial activity with higher effect on pathogenic bacteria (ETECs) than beneficial bacteria (Lactobacillus). Brazilian orange terpenes (BOT) oil presented the highest selective performance and caused higher disturbances on the normal growth kinetic of ETEC than on Lactobacillus rhamnosus. The action was dose-dependent on the maximal culture density (A) and the lag phase duration (λ) of the ETEC. The highest sub-inhibitory concentration (0.925 mg/mL) extended the λ duration to ETEC eight times (14.6 h) and reduced A in 55.9%. For L. rhamnosus, the λ duration was only extended 1.6 times. Despite the fact that limonene was detected as the major compound, the selective antibacterial activity of the citrus EOs could not be exclusively attributed to limonene since the presence of minor compounds could be implicated in conferring this feature

How do the activity patterns of people with chronic pain influence the empathic response of future health professionals: an experimental study.

Funding for open access charge: Universidad de Málaga / CBU

Integration of Remote-Sensing Techniques for the Preventive Conservation of Paleolithic Cave Art in the Karst of the Altamira Cave

[EN] Rock art offers traces of our most remote past and was made with mineral and organic substances in shelters, walls, or the ceilings of caves. As it is notably fragile, it is fortunate that some instances remain intact¿but a variety of natural and anthropogenic factors can lead to its disappearance. Therefore, as a valuable cultural heritage, rock art requires special conservation and protection measures. Geomatic remote-sensing technologies such as 3D terrestrial laser scanning (3DTLS), drone flight, and ground-penetrating radar (GPR) allow us to generate exhaustive documentation of caves and their environment in 2D, 2.5D, and 3D. However, only its combined use with 3D geographic information systems (GIS) lets us generate new cave maps with details such as overlying layer thickness, sinkholes, fractures, joints, and detachments that also more precisely reveal interior¿exterior interconnections and gaseous exchange; i.e., the state of senescence of the karst that houses the cave. Information of this kind is of great value for the research, management, conservation, monitoring, and dissemination of cave art.This research was funded by the Department of Innovation, Industry, Tourism and Trade of the Regional Government of Cantabria in the context of aid to encourage industrial research and innovation in companies, project ¿SImulador Climático del Karst de cuevas de especial valor. (SICLIKA),¿ grant number 2016/INN/25.Bayarri, V.; Prada, A.; García García, F.; Díaz-González, LM.; De Las Heras, C.; Castillo, E.; Fatás, P. (2023). Integration of Remote-Sensing Techniques for the Preventive Conservation of Paleolithic Cave Art in the Karst of the Altamira Cave. Remote Sensing. 15(4). https://doi.org/10.3390/rs1504108715

Influence of Regulatory Fit Theory on Persuasion from Google Ads: An Eye Tracking Study

Search engine marketing accounts for a high percentage of investment in platforms such as Google. Several studies have confirmed that users have a negative bias towards advertisements, so we apply social psychology theories via the elaboration probability model in this analysis. In this research, we modify the types of ads shown on Google’s results pages using the regulatory focus and fit and message framing theory to study attentional and behavioral responses with eye-tracking technology and cognitive responses from self-report measures. The results confirm a negative bias towards ads and a preference for organic results. Although promotion-framed ads seem to be more persuasive than neutral and prevention-framed ads, it was not possible to prove compliance with regulatory fit in this field through survey-based studies.Spanish National R+D+I Research Program - NeuroTourism project (grant no. ECO2017-88458-R)Andalusian R+D+I Research Program - “Research in NeuroSOCOM” project (grant no. B-SEJ-209-UGR18

Novel role for amphiregulin in protection from liver injury

Clinically, the Fas and Fas ligand system plays a central role in the development of hepatocyte apoptosis, a process contributing to a broad spectrum of liver diseases. Therefore, the development of therapies aimed at the inhibition of hepatocyte apoptosis is a major issue. Activation of the epidermal growth factor receptor has been shown to convey survival signals to the hepatocyte. To learn about the endogenous response of epidermal growth factor receptor ligands during Fas-mediated liver injury we investigated the expression of epidermal growth factor, transforming growth factor alpha, heparin-binding epidermal growth factor-like growth factor, betacellulin, epiregulin, and amphiregulin in the liver of mice challenged with Fas-agonist antibody. Amphiregulin expression, barely detectable in healthy liver, was significantly up-regulated. Amphiregulin administration abrogated Fas-mediated liver injury in mice and showed direct anti-apoptotic effects in primary hepatocytes. Amphiregulin activated the Akt and signal transducer and activator of transcription-3 survival pathways, and up-regulated Bcl-xL expression. Amphiregulin knock-out mice showed signs of chronic liver damage in the absence of any noxious treatment, and died faster than wild type mice in response to lethal doses of Fas-agonist antibody. In contrast, these mice were more resistant against sublethal liver damage, supporting the hypothesis that chronic liver injury can precondition hepatocytes inducing resistance to subsequent cell death. These results show that amphiregulin is a protective factor induced in response to liver damage and that it may be therapeutic in liver diseases

High-resolution (sub-decadal) pollen analysis of varved sediments from lake Montcortès (South-central pre-Pyrenees): a fine-tuned record of landscape dynamics and human impact during the last 500 years.

A high-resolution (average 6 years/sampling interval) palaeoenvironmental reconstruction using pollen, charcoal and non-pollen palynomorphs was carried out on annually laminated sediments of Lake Montcortès (southern Pyrenean flank). The results were combined with historical data to better understand landscape evolution and human interaction during the last 500 years. Our results show that human activities (cropping, livestock breeding and hemp cultivation and retting) have been the most important factors responsible for vegetation changes with highest intensity between 1530 and 1900 CE. By means of a sub-decadal study we have been able to evaluate short-lasting events at local and regional scales related to climate (heavy rainfall events and, high-land forest fluctuations) or to historical and well-dated and documented socio-economic events (i.e., crop promotions (hemp) or land abandonment-population emigration). The temporal extent (400 years) and continuity of Cannabis pollen peak have been confirmed, and new evidence of water quality changes, likely as a consequence of hemp retting practices between the mid-17th to late 19th century, are provided. This is the first high-resolution palaeoenvironmental study carried out in a varved lake on the Iberian Peninsula so far. With these data we hope to contribute to filling the gap in high-resolution palaeoenvironmental data

Seasonal patterns of pollen sedimentation in Lake Montcortès (Central Pyrenees) and potential applications to high-resolution paleoecology: a two-year pilot study.

Lakes with varved sediments are especially well suited for paleoecological study, from annual to even seasonal resolution. The interpretative power of such high-resolution paleoenvironmental reconstructions relies on the availability of modern analogs with the same temporal resolution. We studied seasonal pollen sedimentation in varved Lake Montcorte`s, Central Pyrenees (Spain), as a modern analog for highresolution reconstruction of Late Holocene vegetation and landscape dynamics. Seasonal samples were obtained from sediment traps that were submerged near the maximum water depth for a 2-year period (fall 2013 to fall 2015). Seasonal pollen sedimentation was compared with meteorological variables from a nearby weather station. Bulk pollen sedimentation, dominated by Pinus (pine) and Quercus (oak), followed a clear seasonal pattern that peaked during the spring/summer, coinciding with maximum temperature and precipitation, minimum relative humidity and moderate winds from the SSE. Pollen sedimentation lags (PSL) were observed for most pollen types, as substantial amounts of pollen were found in the traps outside of their respective flowering seasons. Two pollen assemblages were clearly differentiated by their taxonomic composition, corresponding to spring/summer and fall/winter. This pattern is consistent with existing interpretation of the sediment varves, specifically, that varves are formed by two-layer couplets that represent the same seasonality as pollen. We concluded that pollen sedimentation in Lake Montcorte`s exhibits a strong seasonal signal in the quantity of pollen, the taxonomic composition of the pollen assembalges, and relationships between the pollen and meteorological variables. Thus, varved sediments provide a potentially powerful tool for paleoecological reconstruction at seasonal resolution. This method could be used not only to identify paleoenvironmental trends, but also to identify annual layers and therefore date sediments, even in the absence of evident sediment laminations. A satisfactory explanation of PSL will require further studies that examine internal lake dynamics and pollen production/dispersal patterns