Saturated Esters Research Articles

Rapid Untargeted Puff‐by‐Puff Analysis of (Electronic) Cigarette Emissions by Concentric Dielectric Barrier Discharge Ionisation Mass Spectrometry

Despite the soaring popularity of e‐cigarettes among teenagers and young adults, our understanding of the full extent of their health hazards have remained limited. This is due to the vast complexities of e‐cigarette aerosols and the difficulty in their full characterisation. Conventional mass spectrometry methods of e‐cigarette analysis, though pioneering in driving political and medical discourse, have been limited in their capabilities to uncover all compounds in its emissions due to prominent limitations in experimental setup. To overcome this major hurdle, we have developed a setup for puff‐by‐puff analysis of electronic and conventional cigarette emissions by concentric dielectric barrier discharge ionisation mass spectrometry. In this pilot study, the simple setup of in‐line dilution and high‐resolution mass spectrometry analysis allowed us to directly uncover 225 compounds in e‐cigarette puffs across a wide spectrum of chemical characteristics in two sequential 5‐minute runs. These include acids, carbonyls, aromatic cyclics, heterocyclics, unsaturated and saturated hydrocarbons, alcohols, esters, alkaloids, sulfur‐containing compounds, oxides, and nitriles. As a result, our setup provided a significant improvement in rapid compound identification, and demonstrated a much broader chemical landscape in e‐cigarette emissions than previously reported.

Enrichment of EPA and DHA in glycerides by selective enzymatic ethanolysis

It has been reported that eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in glycerides have various biological functions. This study presents an effective method for enriching glycerides rich in EPA and DHA through lipase-catalyzed alcoholysis. The results showed that Eversa® Transform 2.0 had the strongest discrimination against DHA and EPA in alcoholysis, which was verified by molecular docking. Additionally, selectivity of the lipase and ratio of DHA and EPA in glyceride products were significantly affected by alcohol type. Under the optimal conditions, the contents of EPA and DHA in glycerides after ethanolysis reached 12.91 % and 55.40 %, respectively, with a DHA yield of 79.22 %. In this study, an interesting finding was that Eversa® Transform 2.0 could effectively differentiate EPA and DHA during alcoholysis to allow us to prepare DHA-enriched glycerides and EPA-enriched ethyl esters after removing saturated and monounsaturated ethyl esters.

Microbial dynamics, chemical profile, and bioactive potential of diverse Egyptian marine environments from archaeological wood to soda lake

Halophilic archaea are a unique group of microorganisms that thrive in high–salt environments, exhibiting remarkable adaptations to survive extreme conditions. Archaeological wood and El–Hamra Lake serve as a substrate for a diverse range of microorganisms, including archaea, although the exact role of archaea in archaeological wood biodeterioration remains unclear. The morphological and chemical characterizations of archaeological wood were evaluated using FTIR, SEM, and EDX. The degradation of polysaccharides was identified in Fourier transform infrared analysis (FTIR). The degradation of wood was observed through scanning electron microscopy (SEM). The energy dispersive X–ray spectroscopy (EDX) revealed the inclusion of minerals, such as calcium, silicon, iron, and sulfur, into archaeological wood structure during burial and subsequent interaction with the surrounding environment. Archaea may also be associated with detected silica in archaeological wood since several organosilicon compounds have been found in the crude extracts of archaeal cells. Archaeal species were isolated from water and sediment samples from various sites in El–Hamra Lake and identified as Natronococcus sp. strain WNHS2, Natrialba hulunbeirensisstrain WNHS14, Natrialba chahannaoensis strain WNHS9, and Natronococcus occultus strain WNHS5. Additionally, three archaeal isolates were obtained from archaeological wood samples and identified as Natrialba chahannaoensisstrain W15, Natrialba chahannaoensisstrain W22, and Natrialba chahannaoensisstrain W24. These archaeal isolates exhibited haloalkaliphilic characteristics since they could thrive in environments with high salinity and alkalinity. Crude extracts of archaeal cells were analyzed for the organic compounds using gas chromatography–mass spectrometry (GC–MS). A total of 59 compounds were identified, including free saturated and unsaturated fatty acids, saturated fatty acid esters, ethyl and methyl esters of unsaturated fatty acids, glycerides, phthalic acid esters, organosiloxane, terpene, alkane, alcohol, ketone, aldehyde, ester, ether, and aromatic compounds. Several organic compounds exhibited promising biological activities. FTIR spectroscopy revealed the presence of various functional groups, such as hydroxyl, carboxylate, siloxane, trimethylsilyl, and long acyl chains in the archaeal extracts. Furthermore, the archaeal extracts exhibited antioxidant effects. This study demonstrates the potential of archaeal extracts as a valuable source of bioactive compounds with pharmaceutical and biomedical applications.

Exploring intermediate temperature reactivity: Experimental and kinetic modeling insights into 50/50% blend of methyl butanoate and methyl crotonate

In this work, an experimental and kinetic modeling study has been conducted to bridge the knowledge gap pertaining to the reactivity of blends of saturated and unsaturated methyl esters at intermediate temperatures. We consider two well-known biodiesel surrogates: the saturated ester methyl butanoate and the unsaturated ester methyl crotonate. These compounds were considered due to the wealth of experimental and modeling data available in the literature for the molecules. We conducted experiments to measure ignition delay times of mixtures of methyl butanoate and methyl crotonate using a Rapid Compression Machine (RCM) across different equivalence ratios (0.5, 1.0, 1.5) and at pressures of 20 and 30 bar. Furthermore, we developed an improved kinetic model that thoroughly validates the newly obtained RCM experimental data for the blend of methyl butanoate and methyl crotonate, in addition to existing experimental studies for the individual components. Present kinetic modeling work involved the incorporation of several new reaction pathways and rates, resulting in improved predictions of combustion characteristics. This study offers insights into the various reaction pathways that influence the reactivity of the blend as well as explains the interactions between methyl butanoate and methyl crotonate based on the underlying kinetics.

Prolonged corrosion protection via application of 4-ferrocenylbutyl saturated carboxylate ester derivatives with superior inhibition performance for mild steel

A series of 4-ferrcenylbutyl carboxylate esters with different alkyl chain length (C2-C4) of carboxylic acids were synthesized using Fe3O4@SiO2@(CH2)3-Im-bisEthylFc[I] nanoparticles as catalyst and have been characterized with FT-IR, 1H NMR, and 13C NMR. Ferrocenyl-based esters were used as corrosion inhibitors of mild steel in the 1M HCl solution as corrosive media. The corrosion inhibition efficiency of the synthesized ferrocenyl-based esters has been assessed by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The 4-ferrocenylbutyl propionate showed a more effective corrosion inhibition behavior among the studied esters with 96% efficiency after immersion in the corrosive media for 2 weeks. The corrosion inhibition mechanism is dominated by formation of passive layer of inhibitor on the surface of the mild steel by adsorption. Moreover, the adsorption characteristics of 4-butylferrcenyl carboxylate esters on mild steel were thoroughly explored using density functional theory calculations. It was found that the Fe atoms located around the C impurity in the mild steel are the most efficient and active sites to adsorb 4-butylferrcenyl carboxylate esters.

Competing Mechanisms in Palladium-Catalyzed Alkoxycarbonylation of Styrene.

Palladium-catalyzed carbonylation is a versatile method for the synthesis of various aldehydes, esters, lactones, or lactams. Alkoxycarbonylation of alkenes with carbon monoxide and alcohol produces either saturated or unsaturated esters as a result of two distinct catalytic cycles. The existing literature presents an inconsistent account of the procedures favoring oxidative carbonylation products. In this study, we have monitored the intermediates featured in both catalytic cycles of the methoxycarbonylation of styrene PhCH=CH2 as a model substrate, including all short-lived intermediates, using mass spectrometry. Comparing the reaction kinetics of the intermediates in both cycles in the same reaction mixture shows that the reaction proceeding via alkoxy intermediate [PdII]-OR, which gives rise to the unsaturated product PhCH=CHCO2Me, is faster. However, with an advancing reaction time, the gradually changing reaction conditions begin to favor the catalytic cycle dominated by palladium hydride [PdII]-H and alkyl intermediates, affording the saturated products PhCH2CH2CO2Me and PhCH(CO2Me)CH3 preferentially. The role of the oxidant proved to be crucial: using p-benzoquinone results in a gradual decrease of the pH during the reaction, swaying the system from oxidative conditions toward the palladium hydride cycle. By contrast, copper(II) acetate as an oxidant guards the pH within the 5-7 range and facilitates the formation of the alkoxy palladium complex [PdII]-OR, which favors the oxidative reaction producing PhCH=CHCO2Me with high selectivity. Hence, it is the oxidant, rather than the catalyst, that controls the reaction outcome by a mechanistic switch. Unraveling these principles broadens the scope for developing alkoxycarbonylation reactions and their application in organic synthesis.

Volatile organic compounds in the habitat of the escamolera ant (Liometopum apiculatum Mayr) in Zacatecas, Mexico

Volatile organic compounds (VOCs) take part in the biological processes of insects; however, these compounds have not been determined for genus Liometopum. The objective of this study was to identify the variability of the VOCs found in the Liometopum apiculatum habitat during the exploitation season. During the 2017 preseason and season, 35 air samples were collected from the nests of five L. apiculatum colonies established in crassicaule scrub vegetation; additionally, another 35 samples were taken from their foraging sites. Using a gas chromatograph with an electronic nose detector, the VOCs were identified with the Kovats index. In addition, a principal component analysis (PCA) was carried out to evaluate the intensity variability per season. Fourty-eight VOCs were identified in the L. apiculatum habitat. The most significant VOCs included: saturated hydrocarbon (17%), aldehydes (17%), alcohols (15%), and esters (10%). PCA accounted for 79.5% (PC1=53.8 and PC2=25.7) of the intensity variability of the VOCs in the habitat between seasons. The escamol season was characterized by the 3-methyl-3-sulfonyl butan-1-ol, 2-Methylbutanoic acid, and trimethylamine. This profile of the VOCs in the L. apiculatum habitat is a pioneer work and has future implications for the conservation and sustainable exploitation of the escamolera ant.

Discrimination of lipid composition and cellular localization in human liver tissues by stimulated Raman scattering microscopy.

The molecular mechanisms driving the progression from nonalcoholic fatty liver (NAFL) to fibrosing steatohepatitis (NASH) are insufficiently understood. Techniques enabling the characterization of different lipid species with both chemical and spatial information can provide valuable insights into their contributions to the disease progression. We extend the utility of stimulated Raman scattering (SRS) microscopy to characterize and quantify lipid species in liver tissue sections from patients with NAFL and NASH. We applied a dual-band hyperspectral SRS microscopy system for imaging tissue sections in both the C-H stretching and fingerprint regions. The same sections were imaged with polarization microscopy for detecting birefringent liquid crystals in the tissues. Our imaging and analysis pipeline provides accurate classification and quantification of free cholesterol, saturated cholesteryl esters (CEs), unsaturated CE, and triglycerides in liver tissue sections. The subcellular resolution enables investigations of the heterogeneous distribution of saturated CE, which has been under-examined in previous studies. We also discovered that the birefringent crystals, previously found to be associated with NASH development, are predominantly composed of saturated CE. Our method allows for a detailed characterization of lipid composition in human liver tissues and enables further investigation into the potential mechanism of NASH progression.

Branched saturated esters and diesters: Sustainable synthesis of excellent biolubricants

The enzymatic production of biolubricants with desirable properties such as high viscosity index and resistance to oxidation is investigated. These characteristics are ascribed to their branched structure and high molecular weight, as well as, to the absence of unsaturated bonds in the molecule. Solvent-free processes with moderate enzyme concentrations (up to 5% wt.) and reaching conversions of 95% or more, have been conducted. Firstly, up to fifteen branched esters and diesters, all of them saturated, are obtained from a branched acid, 2-methylhexanoic acid, and a variety of linear and branched alcohols and linear diols. Among them, three esters have viscosity indexes close to 200 or higher (1,10-decanediolyl 2-methylhexanoate, 1,12-dodecanediolyl 2-methylhexanoate and 2-octyl-1-dodecanoyl 2-methylhexanoate). For the synthesis of these compounds, optimization of biocatalyst concentration and temperature has been carried out, reaching conversions above 95% within operation times between 2 and 3.5 h.

Spectral fingerprinting of cellular lipid droplets using stimulated Raman scattering microscopy and chemometric analysis.

Hyperspectral stimulated Raman scattering (SRS) microscopy is a powerful method for direct visualisation and compositional analysis of cellular lipid droplets. Here we report the application of spectral phasor analysis as a convenient method for the segmentation of lipid droplets using the hyperspectral SRS spectrum in the high wavenumber and fingerprint region of the spectrum. Spectral phasor analysis was shown to discriminate six fatty acids based on vibrational spectroscopic features in solution. The methodology was then applied to studying fatty acid metabolism and storage in a mammalian cancer cell model and during drug-induced steatosis in a hepatocellular carcinoma cell model. The accumulation of fatty acids into cellular lipid droplets was shown to vary as a function of the degree of unsaturation, whilst in a model of drug-induced steatosis, the detection of increased saturated fatty acid esters was observed. Taking advantage of the fingerprint and high wavenumber regions of the SRS spectrum has yielded a greater insight into lipid droplet composition in a cellular context. This approach will find application in the label-free profiling of intracellular lipids in complex disease models.

Evaluation of Chemical Constituents and Antioxidant Activity of Extracts of Nardostachys jatamansi (D. Don) DC.

Nardostachys jatamansi is an endangered medicinal plant of the Caprifoliaceae family. The main aim of this study was to evaluate the metabolites and their biological activities. The shade dried, powdered plant materials were subjected to successive ultrasonic extraction with solvents hexane, chloroform, ethyl acetate, and methanol in the increasing order of polarity. Flavonoids, terpenoids, saponins, phenolic volatile oils, and alkaloids were discovered in the phytochemical screening. Gas chromatography mass spectrometry analysis identified 13, 10, and 6 chemical compounds in hexane, chloroform, and ethyl acetate extracts, respectively. Cyclic saturated hydrocarbons, organic acids, alcohol, and ester were the main constituents of extracts verified by GC-MS. Chloroform extracts had a higher phenolic content (49.53 mg GAE/g) than ethyl acetate extracts (44.41 mg GAE/g). Chloroform extracts had a higher total flavonoid concentration (18.42 mg QE/g) than ethyl acetate extracts (10.57 mg QE/g). The half-maximum inhibitory concentration (IC50) of the chloroform and ethyl acetate extracts revealed moderate results to antioxidant activity.

Leveraging the Proximity and Distribution of Cu−Cs Sites for Direct Conversion of Methanol to Esters/Aldehydes

AbstractMethanol serves as a versatile building‐block for various commodity chemicals, and the development of industrially promising strategies for its conversion remains the ultimate goal in methanol chemistry. In this study, we design a dual Cu−Cs catalytic system that enables a one‐step direct conversion of methanol and methyl acetate/ethanol into high value‐added esters/aldehydes, with customized chain length and saturation by leveraging the proximity and distribution of Cu−Cs sites. Cu−Cs at a millimeter‐scale intimacy triggers methanol dehydrogenation and condensation, involving proton transfer, aldol formation, and aldol condensation, to obtain unsaturated esters and aldehydes with selectivities of 76.3 % and 31.1 %, respectively. Cu−Cs at a micrometer‐scale intimacy significantly promotes mass transfer of intermediates across catalyst interfaces and their subsequent hydrogenation to saturated esters and aldehydes with selectivities of 67.6 % and 93.1 %, respectively. Conversely, Cu−Cs at a nanometer‐scale intimacy alters reaction pathway with a similar energy barrier for the rate‐determining step, but blocks the acidic‐basic sites and diverts the reaction to byproducts. More importantly, an unprecedented quadruple tandem catalytic production of methyl methacrylate (MMA) is achieved by further tailoring Cu and Cs distribution across the reaction bed in the configuration of Cu−Cs||Cs, outperforming the existing industrial processes and saving at least 15 % of production costs.

Leveraging the Proximity and Distribution of Cu-Cs Sites for Direct Conversion of Methanol to Esters/Aldehydes.

Methanol serves as a versatile building-block for various commodity chemicals, and the development of industrially promising strategies for its conversion remains the ultimate goal in methanol chemistry. In this study, we design a dual Cu-Cs catalytic system that enables a one-step direct conversion of methanol and methyl acetate/ethanol into high value-added esters/aldehydes, with customized chain length and saturation by leveraging the proximity and distribution of Cu-Cs sites. Cu-Cs at a millimeter-scale intimacy triggers methanol dehydrogenation and condensation, involving proton transfer, aldol formation, and aldol condensation, to obtain unsaturated esters and aldehydes with selectivities of 76.3 % and 31.1 %, respectively. Cu-Cs at a micrometer-scale intimacy significantly promotes mass transfer of intermediates across catalyst interfaces and their subsequent hydrogenation to saturated esters and aldehydes with selectivities of 67.6 % and 93.1 %, respectively. Conversely, Cu-Cs at a nanometer-scale intimacy alters reaction pathway with a similar energy barrier for the rate-determining step, but blocks the acidic-basic sites and diverts the reaction to byproducts. More importantly, an unprecedented quadruple tandem catalytic production of methyl methacrylate (MMA) is achieved by further tailoring Cu and Cs distribution across the reaction bed in the configuration of Cu-Cs||Cs, outperforming the existing industrial processes and saving at least 15 % of production costs.

The vaporization enthalpies and vapor pressures of Vescepa® and related unsaturated marine FAME by correlation gas chromatography

This article combines data from two previous reports together with new data dealing with the vaporization enthalpies and vapor pressures of a series of saturated and unsaturated fatty acid methyl ester(s) (FAME) by correlation gas chromatography. The work updates earlier results using newly proposed vaporization enthalpies for the saturated FAME used as standards in previous work. This update also provides some insight into the requirements necessary for appropriate column and standard selection for experiments using correlation gas chromatography. Vaporization enthalpies and vapor pressures for saturated FAME methyl heneicosanoate, methyl docosanoate, and methyl tetracosanoate are re-evaluated and together with proposed literature values for methyl tetradecanoate to methyl eicosanoate, are used to evaluate similar properties for a series of unsaturated fatty acid esters. Updated results on the vaporization enthalpies and vapor pressures of a number of unsaturated fatty acid methyl esters (FAME) found in marine oil are reported including several relatively reactive omega-3-polyunsaturated esters. Omega-3-FAME include methyl (9,12,15)Z-octadecatrienoate, methyl (5,8,11,14,17)Z-eicosapentaenoate, and methyl (4,7,10,13,16,19)Z-docosahexenoate among other unsaturated methyl esters. Also included in the study of the omega-3-unsaturated esters is the drug Vescepa®, ethyl (5,8,11,14,17)Z-eicosapentaenoate, a drug used to lower triglyceride levels.

SENSORY, GC-MS AND FTIR ANALYSIS OF AQUEOUS EXTRACT OF HIBISCUS SABDARRIFFA AND VERNONIA AMYGDALINA HERBAL TEA WITH BLENDS OF GINGER AND LEMON ZEST

The use of herbal remedies, especially in the form of teas for management of various diseases is gaining increasing popularity, making them the main stay of health care system, especially among the rural populace in the developing countries. Therefore, it is imperative to carryout proper analysis and screening of these plants, such as Hibiscus Sabdarriffa and Vernonia Amygdalina, to investigate their informed use. This research aimed at producing herbal teas from leaves of Hibiscus Sabdarriffa and Vernonia Amygdalina with additives of ginger and lemon zest with acceptable sensory attributes and also to investigate the phytocomponents of these herbal teas produced using GC-MS spectroscopy and FTIR spectroscopy. Ginger, lemon zest and fresh leaves of Hibiscus Sabdarriffa and Vernonia Amygdalina were collected from modern market areas of makurdi Benue State, authenticated by a plant taxonomist in Department of Botany, University of Agriculture Makurdi. Aqueous extracts of the herbal teas were analyzed using GC-MS Clarus 500 Perkin Elmer system. Identification of functional groups of samples (was done using FT-IR spectroscope (Shimadzu, IR Affinity 1, Japan). Results: FT-IR analysis of the herbal tea samples revealed the presence of phytochemicals like alkanes, alkenes, Carboxylic acids, phenols, alcohols, flavonoids, aromatics and saturated aliphatic esters,. GC-MS analyses of aqueous extract of the samples provided different peaks determining the presence of twenty two compounds with highest abundance. Twelve compounds were identified for Vernonia Amygdalina herbal tea sample and ten for Hibiscus Sabdarriffa herbal tea sample. The findings from this research showed that herbal teas produced from leave of Hibiscus Sabdarriffa and Vernonia Amygdalina had acceptable sensory attributes and also contains bioactive constituents of pharmacological importance for management of diseases which were identified by GC-MS and FTIR analysis.

High-pressure phase equilibrium data for the carbon dioxide + methyl esters homologous series and SAFT-VR Mie modelling

High-pressure phase transition data measured using a visual static synthetic method are presented for various CO2 + saturated fatty acid methyl ester systems in the range 308–358 K and up to 27.5 MPa. The newly measured data cover methyl esters between methyl decanoate and methyl docosanoate in the liquid-like, mixture critical and vapour-like regions, and complement previously published data. The systems studied do not suggest three-phase behaviour, liquid-liquid immiscibility or temperature inversions in the temperature range considered. An increase in temperature and molecular mass of the methyl ester leads to an increase in the phase transition pressure. The SAFT-VR Mie equation of state was able to correlate the data well with decreasing performance at higher methyl ester molecular masses and lower temperatures.

Cultivation of Chlorella minutissima under a novel phosphate application strategy for biodiesel production: A pilot scale study

Microalgal biodiesel is considered as a carbon-neutral and renewable energy source for replacing/blending with petroleum-based diesel fuel. Selection of a microalgal species for its potential to produce biodiesel relies significantly on its acclimatization to grow in outdoor condition with high lipid productivity. The present investigation undertakes outdoor experiments in a raceway pond system involving a local isolate of green microalga, Chlorella minutissima, throughout varied seasonal changes and culture depth. The variations in climatic and cultural parameters were documented; the optimum culture depth of 30 cm was taken for further investigation. A novel cultivation approach incorporating the sequential addition of low-dose phosphate (LDSPA) projected a lipid productivity of 5.88 ton hectare−1 year−1, which was ∼40% higher than its batch culture counterpart, along with a 14-fold reduction in phosphate application. The biodiesel exhibited the dominance of saturated and monounsaturated fatty acid methyl esters, and the fuel qualities were confirmed to be within the stipulated limitations of European, American and Indian biodiesel standards, thus nominating C. minutissima as an attractive feedstock for generating high-quality biodiesel.

Shock tube experiments and kinetic modeling of ignition of unsaturated [formula omitted] methyl esters

Ignition delay times (IDTs) of methyl crotonate (MC), methyl 3-butanoate (MB3D), and methyl methacrylate (MMA), were systematically measured to explore the influences of the position of unsaturated CC double bond and the structure of alkyl chain on ignition characteristics of unsaturated C5 methyl esters. Experiments were performed at 1108–1783 K and 4–16 atm with the equivalance ratio ranging from 0.25 to 2 in a shock tube. Reactivities of three unsaturated esters are similar: their IDTs increase with decreasing temperature and increasing equivalence ratio but are less sensitive to pressure. To gain the insight into differences in kinetics during fuel ignition, the literature MC, MB3D and MMA models were evaluated and the MMA model was updated. Sensitivity and reaction pathway analyses show that the hydrogen-abstraction, unimolecular decomposition, and radical addition reactions are important in controlling MC ignition. However, only hydrogen-abstraction and radical addition reactions show the significance during MB3D and MMA ignitions. Furthermore, the impact of saturation was also explored. The saturated methyl esters have slightly longer IDTs than MC, MB3D, and MMA under fuel-lean conditions with T> 1350 K, because the unsaturated methyl esters are the key intermediates and the hydrogen-abstraction reactions dominate the consumption of saturated esters.

Synthesis and Antineoplastic Efficacy of Anthraquinone and Saturated Fatty Acid Conjugates

AbstractThe clinical use of anthraquinone antibiotics such as doxorubicin in cancer chemotherapy is limited due to their toxic cardiomyopathy effects. The conjugation of anthraquinones with fatty acids is known to enhance bioactivity by increasing lipophilicity and facilitating cell membrane permeation. Short‐chain saturated fatty acids such as capric, caprylic, caproic acids, and lauric acids are known for their inherent anticancer properties on human colorectal cancer cells. In this study, 2‐hydroxyanthraquinone and saturated fatty acid esters were synthesized and evaluated against human colon cancer cell line HT‐29 and Colo‐205, breast cancer cell lines MDA‐MB‐231 and MCF‐7, and leukemia cell line K‐562 for their in vitro anticancer properties using a sulforhodamine B (SRB) assay. The anthraquinone‐saturated fatty acid conjugates produced excellent activity against human colon and breast cancer cell lines. The octanoic acid and hexanoic acid derivatives of 2‐hydroxy anthraquinone showed excellent anticancer activity with GI50 values of 0.2 nM and 1.0 nM against human colon cancer cell line Colo‐205 and the human breast cancer cell line MCF‐7, respectively, and emerged as the most active compounds. Furthermore, the in vitro cytotoxicity study against peripheral blood mononuclear cells showed that these derivatives are non‐toxic in nature.

Optimization of microwave-assisted biodiesel production from watermelon seeds oil using thermally modified kwale anthill mud as base catalyst

A heterogeneous catalyst was developed from raw Kwale red Anthill mud by thermal treatment in a muffle furnace at 900 °C for 4 h. The resulting heterogeneous catalyst was highly porous with a surface area of 42.16m2/g, possessing excellent stability as well as high catalytic activity. Central Composite Design and Machine Learning approach (Python code) were applied to model and optimize biodiesel yield from extracted watermelon oilseed. Highest biodiesel yield of 93.41 wt% was obtained under the experimental conditions of 4min duration, 350 W microwave power, 4 wt% of catalyst, and MeOH/oil ratio of 8:1 based on Central Composite Design rotatable. The optimum value of the biodiesel yield from Machine Learning was 91.7 wt%, showing a marginal performance over the Central Composite Design rotatable value (91.6 wt%) at the optimized conditions of 3 min, 280 W, 3 wt% catalyst loading and MeOH/oil molar ratio of 6:1. The correlation of the coefficient (R2) of the model was 0.9827 for Central Composite Design rotatable while the R2 of the Machine Learning model was 1.0. Thus, python coding in terms of prediction and accuracy of biodiesel yield was superior to Central Composite Design rotatable, even though both models provide a reliable response within the region of data analyzed. The Gas Chromatography-Mass Spectroscopy of the biodiesel produced revealed the presence of both saturated and unsaturated fatty acid methyl esters. Biodiesel properties from watermelon seed oil transesterification fall within the recommended standard for biodiesel fuel. This study concluded that an effective green biowaste catalyst generated from earthen waste could enhance biodiesel production from watermelon seed oil, hence, ensuring sustainability and economic feasibility for biodiesel industries.