This article describes the influence of different sugarcane bagasse hydrolysis pretreatments on modifications to biomass feedstock and the characteristics of the resultant pyrolysis products. ...Sugarcane bagasse was pretreated with acid, alkaline or sequential acid/alkaline solutions and pretreated samples were then subjected to a low temperature conversion (LTC) process under He or O
2/He atmospheres at 350–450 °C. Both pretreated samples and sugarcane bagasse
in natura were analyzed by determination of their chemical composition and by thermogravimetric, FTIR and SEM analyses. The gases yielded during LTC were monitored on-line by quadrupole mass spectrometry, and the liquid fractions obtained were characterized by FTIR and
1H and
13C NMR. Irrespective of the sugarcane bagasse pretreatment applied, the main bio-oil component obtained was levoglucosan. However, the LTC yield of bio-oil depended on the hydrolysis treatment of the biomass and decreased in the presence of O
2. The acid hydrolysis pretreatment increased the LTC bio-oil yield notably.
► Sugarcane bagasse modified by acid, alkaline or sequential acid/alkaline hydrolysis. ► LTC-pyrolysis at 350–450 °C under He or O
2/He of pretreated sugarcane bagasse. ► Yield of bio-oil depended on hydrolysis treatment and decreased in presence of O
2. ► The acid hydrolysis pretreatment increased the LTC bio-oil yield notably (72% in He). ► Levoglucosan was the main bio-oil component obtained.
The species
K.Schum is a tree belonging to the Rubiaceae family, endemic in Brazil. So far, there are reports neither of phytochemical work nor of biological evaluation of it. The analysis by High ...Performance Liquid Chromatography coupled to a Diode Array Detector and a tandem Mass Spectrometer with an Electrospray Ionization source (HPLC-DAD-ESI-MS/MS) of its crude extract allowed to characterize in a complex mixture, without isolation, fourteen compounds, being two as cinnamic acid derivatives, and the others as mono-, di- and triglycosilated derivatives of the flavonols quercetin and kaempferol. These compounds are reported for the first time in
spp.
Introduction
The methanol (MeOH) leaf extracts of the species Faramea bahiensis, F. hyacinthina and F. truncata (Rubiaceae) have previously shown in vitro non‐cytotoxic and anti‐dengue virus serotype ...2 (DENV2) activities in human hepatocarcinoma cell lineage (HepG2). Chemical studies have led to the isolation of major flavonoids, but quite complex fractions of phenolic compounds still remain.
Objective
To complete the study of phenolic compounds in the leaves and to access the presence of these compounds in the stems of these Faramea spp. by online high‐performance liquid chromatography‐diode array detector‐electrospray ionisation tandem mass spectrometry (HPLC‐DAD‐ESI‐MS/MS), as well as to evaluate the in vitro cytotoxic and anti‐DENV2 activities of their MeOH stem extracts.
Methodology
The identification was performed by comparing retention times, UV and mass spectra with those of available standards and by using the mechanisms and fragmentation patterns established in previous studies. The effects of the extracts in DENV2 infected HepG2 cell viability was determined by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The virus titer was quantified by plaque assay.
Results
The study led to the characterisation of 31 phenolic compounds including flavonoid O‐ and C‐glycosides, phenolic acids and one coumarin. The stem extracts from F. hyacinthina and F. bahiensis presented a similar bioactivity to those of their leaves but a loss of cytoprotective activity of F. bahiensis and a higher cytotoxicity of F. truncata were observed.
Conclusions
This research allowed a detailed phenolic composition of three bioactive Faramea species to be achieved, thus contributing to the study of this genus and providing valuable information for further phytotherapeutic applications.
The presence of 31 phenolic compounds in leaves and stems of Faramea bahiensis, F. hyacinthina and F. truncata was achieved by HPLC‐DAD‐ESI‐MS/MS. In addition to the previously reported non‐cytotoxicity and anti‐dengue activity of their leaves, an evaluation of these properties in their stems showed that F. hyacinthina and F. bahiensis stems presented a similar bioactivity to those of their leaves but a loss of cytoprotection of F. bahiensis and a higher cytotoxicity of F. truncata were observed.
Leaves of Eugenia florida DC. have been used in folk medicine as hypotensive, hypoglycemic, antipyretic and for gastrointestinal disorders, among others. In this study dried leaves were extracted ...with ethanol and the extract was partitioned with hexane, CHCl3, EtOAc, BuOH and water to afford triterpenoid- and polyphenol-rich fractions which were analyzed by GC-MS and UFLC-DAD-ESI-Ion Trap-MSn. All fractions were tested against the proliferation of leukemic K562 and human melanoma SK-Mel-28 cell lines and for their ability to scavenge DPPH radical. Twenty-nine compounds were fully identified (among triterpenic and phenolic acids, flavonol- and dihydroflavonol-monoglyclosides) based on mass fragmentation patterns and comparison to standards and/or literature data. The ability to scavenge DPPH radical resulted in the following order: BuOH ≈ EtOAc > crude extract ≈ Water >> CHCl3 >> hexane; with the two most active reaching half of the TBHQ control potency (EC50 6.59 ± 0.03 µg mL-1). On testing against the proliferation of K562 and SK-Mel-28 cell lines, the most significant inhibitions were achieved on the former by the crude extract (IC50 12 µg mL-1) and the hexane and EtOAc fractions at 15 µg mL-1.
This work reports the nutritional potential and the antiradical activity of the cladodes of the Brazilian
Opuntia monacantha Haw. (Cactaceae), as well the isolation of kaempferol and isorhamnetin ...through activity-guided fractionation from its active MeOH extract. TLC, HPLC-DAD and NMR techniques were used to detect and identify the compounds. The water (91.1%), ash, protein, fibre and lipid contents (15.0, 5.4, 18.5 and 1.4
g/100
g, respectively) were shown to be quite similar to the mean values of other
Opuntia spp., some widely used as food and forage. The antioxidant activity of their MeOH extract and of its
n-hexane, EtOAc and
n-BuOH fractions was assessed by measuring the ability of the fractions to scavenge DPPH radical, showing an activity enhancement for the fractions in comparison to the crude MeOH extract. The well-known free-radical scavenging activity of the isolated flavonoids reinforces the contribution of these compounds to the presented activity of the
O. monacantha cladodes.
The Amazonian Rubiaceae species Uncaria guianensis (UG) is locally used as antiinflammatory, antitumor, antidiabetic, anti-ulcers, and others. The phenolic content of its leaves is characterized by ...the great predominance of the flavonoid kaempferol-3,7-O-(α)-L-dirhamnoside (kaempferitrin). The present study quantitatively evaluates the kaempferitrin content in the leaves and branches of cultivated and wild UG specimens collected in different locations of the Brazilian Amazon rainforest by employing high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD). Besides, the understanding of the polyphenol profile performed by electron spray ionization is deepened by tandem mass spectrometry analysis (ESI-MS/MS), using a previously approached leaf UG extract, and the flavonoid quercetin-3,7-O-(α)-L-dirhamnoside was first isolated from UG. All samples showed quite similar qualitative polyphenol profiles. Kaempferitrin in UG ranged from 1.1 to 1.9 mg 100 mg-1 for dry leaves of adult wild plants, 0.3 to 0.7 mg 100 mg-1 for dry leaves of cultivated young plants and 0.00 to 0.04 mg 100 mg-1 for dry branches of adult wild plants. Besides suggesting the distribution of kaempferitrin in the species, these results reinforce this flavonol as a suitable chemical marker for UG leaves and the products derived from them.
Uncaria tomentosa (Willd.) DC., a large woody vine native to the Amazon and Central American rainforests has been used medicinally by indigenous peoples since ancient times and has scientifically ...proven immunomodulating, anti-inflammatory, cytotoxic and antioxidant activities. Several inflammatory mediators that are implicated in vascular permeability and shock are produced after Dengue Virus (DENV) infection by monocytes, the primary targets for virus replication. Here we assessed the immunoregulatory and antiviral activities from
U. tomentosa-derived samples, which were tested in an
in vitro DENV infection model. DENV-2 infected human monocytes were incubated with
U. tomentosa hydro-alcoholic extract or either its pentacyclic oxindole alkaloid-enriched or non-alkaloid fractions. The antiviral activity was determined by viral antigen (DENV-Ag) detection in monocytes by flow cytometry. Our results demonstrated an
in vitro inhibitory activity by both extract and alkaloidal fraction, reducing DENV-Ag+ cell rates in treated monocytes. A multiple microbead immunoassay was applied for cytokine determination (TNF-α, IFN-α, IL-6 and IL-10) in infected monocyte culture supernatants. The alkaloidal fraction induced a strong immunomodulation: TNF-α and IFN-α levels were significantly decreased and there was a tendency towards IL-10 modulation. We conclude that the alkaloidal fraction was the most effective in reducing monocyte infection rates and cytokine levels. The antiviral and immunomodulating
in vitro effects from
U. tomentosa pentacyclic oxindole alkaloids displayed novel properties regarding therapeutic procedures in Dengue Fever and might be further investigated as a promising candidate for clinical application.
The leaf MeOH extract of Psychotria leiocarpa (Rubiaceae) showed in vitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). A one-step and ...cost-effective reversed-phase solid-phase extraction method based on high-performance liquid chromatography (HPLC) parameters allowed the isolation, directly from this bioactive extract, of the monoterpene indole alkaloids: N-glucopyranosyl vincosamide (1), vincosamide (2) and strictosidinic acid (3). The chemical structures were characterized based on 1D and 2D nuclear magnetic resonance (NMR), UV and high-resolution mass spectra (HRMS). The methodology has also allowed yielding a polyphenolic-rich fraction that was analyzed by high-performance liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) revealing two flavonol triglycosides (4, 5) and three caffeoylquinic acid isomers (6-8). Compound 3 is reported for the first time in P. leiocarpa and all the phenolic compounds (4-8) are described for the first time in the genus Psychotria. Compounds 1-3 showed to be non-cytotoxic and anti-dengue active towards DENV2, highlighting vincosamide (2).
Ursolic acid (UA), a pentacyclic triterpene acid found in apple peels (
Malus domestica
, Borkh, Rosaceae), has a large spectrum of pharmacological effects. However, the vegetal matrix usually ...produces highly viscous and poorly soluble extracts that hamper the isolation of this compound. To overcome this problem, the crude EtOH–AcOEt extract of commercial apple peels was exhaustively treated with diazomethane, after which methyl ursolate (MU) was purified by column chromatography and characterized spectrometrically. The anti-inflammatory effects of UA and MU (50 mg/kg) were analyzed by zymosan-induced paw edema, pleurisy and in an experimental arthritis model. After 4 h of treatment with UA and MU, paw edema was reduced by 46 and 44 %, respectively. Both UA and MU inhibited protein extravasation into the thoracic cavity; tibio-femoral edema by 40 and 48 %, respectively; and leukocyte influx into the synovial cavity after 6 h by 52 and 73 %, respectively. Additionally, both UA and MU decreased the levels of mediators related to synovial inflammation, such as KC/CXCL-1 levels by 95 and 90 %, TNF-α levels by 76 and 71 %, and IL-1β levels by 57 and 53 %, respectively. Both the compounds were equally effective when assayed in different inflammatory models, including experimental arthritis. Hence, MU may be considered to be a useful anti-inflammatory derivative to overcome the inherent poor solubility of UA for formulating pharmaceutical products.
The public perception of renewable energy sources is generally positive, due to their role in air pollution and CO
emission mitigation policies. However, there are local environmental detrimental ...effects, and empirical evidence is not consistent as to the support of local communities. In the present paper, we analyse the antecedents of public generic perceptions of renewables grounded on objective location-related factors. Personal location-related factors can originate in the involvement of individuals with renewable energy sources. Regional location-related factors concern the importance of the renewable energy source in the district of residence and in relation to other renewables. We implement a questionnaire on public perceptions of renewable energy sources by the general population in mainland Portugal and complement respondent-level responses with renewable energy district information. Regression analysis shows that these objective location-related factors, both personal and regional, help explain public perceptions of renewables and thus we find empirical support for the proposed approach. These results can inform and guide policymakers in tackling future social acceptance issues of renewable energy policies towards lower carbon emissions and less polluting energy production.
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