Alkaline hydrolysis of spent aromatic biomass for production of phenolic aldehydes, lignin, and cellulose.

In order to combat the environmental issues associated with the burning of spent aromatic biomass (SAB), a method for alkaline hydrolysis of SAB has been developed to afford phenolic acids, predominantly the p-coumaric acid, lignin, and cellulose. Lignin (∼15 wt%) from alkaline hydrolysate was separated by precipitation while a mixture of phenolic acids obtained was directly reacted with a green reagent, PhI(OAc)2, under one-pot condition to afford a mixture of p-hydroxybenzaldehyde (>90 wt%) and vanillin (<10 wt%). Unreacted biomass obtained in the process was successfully used as a substrate for the production of cellulose (∼40 wt%). The developed method exhibits potential for application on an industrial scale.

Isolation of Food Grade Dye from Flower Petals of Butea monosperma and Determination of Marker Compounds for Its Quantitative Analysis.

Health concerns associated with synthetic dyes/colorants have fostered the use of natural coloring materials for food applications. This study has been carried out to extract a natural dye from the flower petals of Butea monosperma (family Fabaceae) under an eco-friendly and organic solvent-free approach. Hot aqueous extraction of dry B. monosperma flowers followed by lyophilization of the resulting extract furnished an orange-colored dye in ∼35% yield. Silica gel column chromatography of dye powder resulted in the isolation of three marker compounds, viz. iso-coreopsin (1), butrin (2), iso-butrin (3) which were characterized by spectral methods, e.g., ultra violet, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and high-resolution mass spectrometry. The XRD analysis of isolated compounds established an amorphous nature for compounds 1 and 2 while compound 3 showed good crystallinity. The stability of dye powder and the isolated compounds 1-3 was determined by thermogravimetric analysis which showed excellent stability up to 200 °C. In trace metal analysis, the product B. monosperma dye powder exhibited low relative abundance <4% for Hg along with negligible concentrations of Pb, As, Cd, and Na. The detection and quantification of marker compounds 1-3 in the B. monosperma flower extracted dye powder were carried out by a highly selective UPLC/PDA method of analysis.

Synthesis of deoxy-Andrographolide Triazolyl Glycoconjugates for the Treatment of Alzheimer's Disease.

A new andrographolide-based terminal alkyne 3 was synthesized in good yield from deoxy-andrographolide 2, obtained from a natural compound andrographolide 1, which in turn was isolated from the leaves of the plant Andrographis paniculata. Copper(I)-catalyzed azide-alkyne cycloaddition reaction of alkyne 3 with azido-sugars 4a-f furnished a library of andrographolide-fastened triazolyl glycoconjugates 5a-f in good yields. The structures of these semisynthetic andrographolide derivatives were established by Fourier transform infrared, NMR, and mass spectroscopy. The compounds 5a-f were further evaluated against Alzheimer's disease (AD) using a scopolamine (SCOP)-induced memory impairment mice model. It was observed that antioxidant and anticholinesterase properties of these compounds contribute significantly toward their remarkable potential to improve cognitive functioning.

Click Chemistry Inspired Synthesis of Hydroxyanthracene Triazolyl Glycoconjugates.

Novel hydroxyanthracene-based terminal alkynes 3 and 5a/b were synthesized by the acetylide addition reaction at the 9,10-position of anthraquinone 1 under mild conditions. The developed alkynes 3, 5a, and 5b on Huisgen azide-alkyne cycloaddition reaction with azido-sugars 6 in the presence of Cu(I) catalyst provided a series of triazole fasten hydroxyanthracene glycoconjugates 7, 8, and 9, respectively, in good yields. The representative compounds 9 and 7h were successfully deprotected under room-temperature conditions to liberate the corresponding free glycoconjugates 10 and 11, respectively. Further, structures of a few compounds were unmaliciously evidenced by their single-crystal X-ray.

Solvothermal conversion of spent aromatic waste to ethyl glucosides.

On-farm extraction of commercially important essential oil from aromatic crops generates huge spent aromatic waste. This massive waste is often disposed in the unregulated landfills or burned in the open air to vacate the fields. Hence, a new method for processing of aromatic spent waste has been developed to obtain platform chemicals, such as, xylose and ethyl glucosides. The thermochemical liquefaction of acid pre-treated palmarosa (cymbopogon martini) biomass furnished a mixture of ethyl glucopyranosides in good yield (∼17 wt% relative to biomass) and selectivity (∼77%) by heating with p-cymen-2-sulphonic acid (p-CSA) in the presence of ethanol as a solvent. The detection, quantification and isolation of ethyl glucosides may provide a new application of spent aromatic biomass for use as a feed stock in the production of value added chemicals.

Click chemistry inspired synthesis of andrographolide triazolyl conjugates for effective fluorescent sensing of ferric ions.

The naturally occurring compound andrographolide 1 was used as a substrate for the synthesis of a novel terminal alkyne 3 which on copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction with azides 4a-l, 7 and 9 furnished a series of regioselective andrographolide triazolyl conjugates 5a-l, 8 and 10, respectively. A free glycoconjugate 6 was also prepared by selective deprotection of compound 5i in good yield. All the compounds were characterized by absorbance, FT-IR, NMR, and HR-MS analyses. The triazolyl conjugate 8 was further investigated as a probe for selective detection of Fe3+ ion in matrix. The mode of attachment of Fe3+ ion to the compound 8 was established by absorbance, fluorescence, infrared (IR), and nuclear magnetic resonance (NMR) spectroscopy, and high resolution mass-spectrometry (HR-MS). The logic gate circuits were constructed for the probe 8 and ethylenediaminetetraacetic acid (EDTA). The environmental perspective of probe 8 was investigated in real water samples.

Isolation, optimized extraction, and ultra-high performance liquid chromatography with photodiode array method for quantitative analysis of chiratol in Swertia paniculata.

The global natural product-based industry is growing fast with the introduction of new phytochemicals and herbal extract products from different geographical regions. Swertia paniculata is a well-known plant with medicinal properties; however, the quality control for its major phytochemical constituents from the Himalayan geographical region is nevertheless reported. Therefore, the first objective of this investigation was to characterize and optimize the extraction process while the second objective was to validate a quantitative analytical method for chiratol from S. paniculata herbal extract. The chiratol was characterized with spectral analysis. The optimum extraction condition for the highest yield of metabolite was realized in chloroform as a solvent system under ultrasonication. The ultra-high performance liquid chromatography coupled with photodiode array detection method for analytical quantification was validated for specificity, linearity, limits of detection, limits of quantification, precision, repeatability, recovery, and robustness using Eclipse Plus C18 column (100 mm × 4.6 mm × 3.5 µm id). The gradient elution of water/acetonitrile as mobile phase was used at a flow rate of 0.5 ml/min. The recovery percentage was very satisfactory with values within specification. The robustness parameters showed no substantial influence of evaluated parameters by the Youden test. The developed method was ascertained to be appropriate for the proposed purpose.

A divergent approach for the synthesis of (hydroxymethyl)furfural (HMF) from spent aromatic biomass-derived (chloromethyl)furfural (CMF) as a renewable feedstock.

Extraction of commercial essential oil from several aromatic species belonging to the genus Cymbopogon results in the accumulation of huge spent aromatic waste which does not have high value application; instead, the majority is burned or disposed of to vacate fields. Open burning of spent aromatic biomass causes deterioration of the surrounding air quality. Therefore, a new protocol has been developed for chemical processing of spent biomass to obtain 5-(chloromethyl)furfural (CMF) with high selectivity (∼80%) and yields (∼26 wt% or ∼76 mol% with respect to pre-treated biomass) via refluxing in aqueous HCl in the presence of NaCl as a cheap catalyst. No black tar formation and gasification were observed in the processing of the spent aromatic biomass. Spent aromatic waste-derived CMF was further converted to 5-(hydroxymethyl)furfural (HMF) in good yields by a novel one pot method using iodosylbenzene (PhIO) as a reagent under mild reaction conditions.

Production of xylose, levulinic acid, and lignin from spent aromatic biomass with a recyclable Brønsted acid synthesized from d-limonene as renewable feedstock from citrus waste.

This work aimed to develop a green protocol for chemical processing of spent aromatic biomass to obtain xylose, levulinic acid, and lignin in good yields via treatment with p-cymene-2-sulphonic acid (p-CSA), a Brønsted acid synthesised from d-limonene as a renewable feedstock from citrus waste. Chemical processing of palmarosa biomass with p-CSA under heating in an autoclave resulted in hydrolysate containing xylose (~16% yield). Further processing of pre-treated biomass with p-CSA in presence of aq. HCl under refluxing caused a selective degradation of cellulose to levulinic acid (~22% yield with respect to biomass). The residual biomass was used to afford lignin in good yields.

Delivery of phytochemicals by liposome cargos: recent progress, challenges and opportunities.

Bio-availability is a major concern in delivery of dietary phytochemicals for better bio-efficacy. The reduced bio-availability of food bioactive compounds is evident due to degradation during human digestion process which involves liberation, absorption, distribution, metabolism and elimination. The bio-efficacy of any nutrient can be increased by increasing bio-availability. Different technologies are available for engineered efficient delivery systems; still many challenges remain with advancement of delivery systems. The ease of preparedness and adaptability of liposomes has resulted in wide-range of applicability and acceptability in scientific field, especially as delivery vehicles. In view, of properties like biocompatibility and biodegradability, liposomes have been modified with different usable methodologies for delivery of phytochemicals. The aim of this review is to abridge liposomes, methods of preparation, their application as delivery cargo in dietary phytochemicals, result of using different preparation techniques on properties.

Isolation of a new flavonoid and waste to wealth recovery of 6-O-Ascorbyl Esters from Seeds of Aegle marmelos (family- Rutaceae).

Aegle marmelos is a plant species native to India. Commercially available food products such as jam, jelly, candy, squash etc. are prepared from ripe fruit pulp of A. marmelos. Ripe fruit processing accounts for 60% of whole fruit mass while 40% remains unutilized and generates waste (hard shell, pomace, fiber and seeds) on a massive scale which do not have high value applications. A new flavone 3,5,7-trihydroxy-2-(4'-hydroxy-3'-isopentyloxyphenyl-4H-chromen-4-one (5) in addition to the known compounds 1-4, has been isolated from seeds of A. marmelos. Also, compound 7-(3'-methylbut-2'-enyloxy)-2H-chromen-2-one (2) has been isolated for the first time from A. marmelos. The structure of compounds 1-5 was determined by spectral analysis (UV, IR, NMR, etc.). Additionally, the non-edible oil obtained from seeds was investigated for waste to wealth recovery of 6-O-ascorbyl esters in high regioselectivity via one step semi-synthetic approach in the presence of ascorbic acid and H2SO4 at ambient temperature.

Processing of wet Kinnow mandarin (Citrus reticulata) fruit waste into novel Brønsted acidic ionic liquids and their application in hydrolysis of sucrose.

In citrus processing industries, where up to 60% of the whole fruit is discarded, generates citrus waste (peel, seeds, membrane, and pulp) on a massive scale. The waste does not currently have high-value applications, instead the majority is disposed of or pelletized for animal feed. Therefore, a concise and efficacious protocol for processing of Kinnow mandarin (Citrus reticulata) fruit waste to numerous novel Brønsted acidic ionic liquids (3a-k) have been developed. BAILs were characterized using spectroscopic techniques (FT-IR and NMR). Water immiscibility of ILs 3a, 3g and 3h, a property never observed with sulfonic acid ILs, allowed the catalytic application of BAIL 3a in hydrolysis of sucrose/table sugar, giving a mixture of d-glucose and d-fructose in excellent yields. The ionic liquid could be recycled for >3 times without significant loss of activity.

Click inspired synthesis of triazole-linked vanillin glycoconjugates.

The 1,3-dipolar cycloaddition of deoxy-azido sugars 1 with alkyne derivatives of p-vanillin, 3-methoxy-4-(prop-2-ynyloxy)benzaldehyde (2) and 2-methoxy-1-(prop-2-ynyloxy)-4-((prop-2-ynyloxy)methyl)benzene) (4) to afford regioselective triazole-linked vanillinglycoconjugates 5 and 6 was investigated in the presence of CuI/DIPEA in dichloromethane. All the developed glycoconjugates were characterized on the basis of IR, NMR, and MS. Graphical abstract Triazolyl vanillin glycoconjugates via click chemistry.

A new antifungal eudesmanolide glycoside isolated from Sphaeranthus indicus Linn. (Family Compositae).

A new antifungal eudesmanolide glycoside 11,13-dihydro-3-O-(ß-digitoxopyranose)-7α-hydroxy eudasman-6,12-olide (2) in addition to known compounds 1 and 3, has been isolated from Sphaeranthus indicus Linn. Its structure was determined by spectral analysis (UV, IR, 1D and 2D NMR and mass spectrum).

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry.

Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC), popularly known as the "click reaction", serves as the most potent and highly dependable tool for facile construction of simple to complex architectures at the molecular level. Click-knitted threads of two exclusively different molecular entities have created some really interesting structures for more than 15 years with a broad spectrum of applicability, including in the fascinating fields of synthetic chemistry, medicinal science, biochemistry, pharmacology, material science, and catalysis. The unique properties of the carbohydrate moiety and the advantages of highly chemo- and regioselective click chemistry, such as mild reaction conditions, efficient performance with a wide range of solvents, and compatibility with different functionalities, together produce miraculous neoglycoconjugates and neoglycopolymers with various synthetic, biological, and pharmaceutical applications. In this review we highlight the successful advancement of Cu(I)-catalyzed click chemistry in glycoscience and its applications as well as future scope in different streams of applied sciences.

Click inspired synthesis of antileishmanial triazolyl O-benzylquercetin glycoconjugates.

The 1,3-dipolar cycloaddition of deoxy-azido sugars 1 with O-benzylquercetin alkynes (5-7) to afford regioselective triazole-linked O-benzylquercetin glycoconjugates (8-10) was investigated in the presence of CuI/DIPEA in dichloromethane. All the developed glycoconjugates (8-10) were evaluated for anti-leishmanial activity against the promastigotes and amastigotes of Leishmania donovani. Graphical Abstract Click Inspired Synthesis of Antileishmanial Triazolyl O-Benzylquercetin Glycoconjugates.

Efficient synthesis of ethisterone glycoconjugate via bis-triazole linkage.

Synthesis of sugar based triazolyl azido-alcohols was accomplished via one pot click reaction of glycosyl alkynes with epichlorohydrin in aqueous medium. All the developed triazolyl azido-alcohols were further utilized for the synthesis of bis-triazolyl ethisterone glycoconjugates using CuAAC reaction. The developed triazole-linked ethisterone glycoconjugates would be crucial in androgen receptor pharmacology and chemical biology.

Click chemistry inspired highly facile synthesis of triazolyl ethisterone glycoconjugates.

Numerous deoxy-azido sugars 3 were prepared by the reaction of tosyl/bromo sugars with NaN3 in dry DMF under heating condition. The 1,3-dipolar cycloaddition of deoxy-azido sugars 3 with ethisterone 4 to afford regioselective triazole-linked ethisterone glycoconjugates 5 was investigated in the presence of CuI and DIPEA in dichloromethane or CuSO4·5H2O and sodium ascorbate in aqueous medium. All the developed compounds were characterized by spectroscopic analysis (IR, (1)H &(13)C NMR, and MS spectra). Structure of triazolyl ethisterone glycoconjugate 5a has been further confirmed by its Single Crystal X-ray analysis.

Synthesis of 2-N/S/C-substituted benzothiazoles via intramolecular cyclative cleavage of benzotriazole ring.

The synthesis of numerous 2-N/S/C-substituted benzothiazoles was achieved from substituted thiocarbonylbenzotriazoles via free-radical intramolecular cyclative cleavage of the benzotriazole ring in the presence of (TMS)3SiH and AIBN under mild conditions. The developed methodology demonstrates significant compatibility under microwave conditions and is important as it avoids the use of toxic metals for radical cyclization.