Solvents Of Low Polarity Research Articles

Designing and Demystifying the Lithium Metal Interface toward Highly Reversible Batteries.

Reversible lithium (Li) plating/stripping is essential for building practical high-energy-density batteries based on Li metal chemistry, which unfortunately remains a severe challenge. In this contribution, it is demonstrated that through the rational regulation of strong Li+ -anion coordination structures in a highly compatible low-polarity solvent, 2-methyl tetrahydrofuran, the Li plating/stripping assisted by a nucleation modulation procedure delivers a remarkably high average Coulombic efficiency under rather demanding conditions (99.7% and 99.5% under 1.0mAcm-2 , 3.0mAh cm-2 and 3.0mAcm-2 , 3.0mAh cm-2 , respectively). The exceedingly reversible cycling obtained herein is fundamentally correlated with the flattened Li deposition and minimized solid electrolyte interphase (SEI) generation/reconstruction in the customized condition, which notably restrains the growth rates of both dead Li0 (0.0120mAh per cycle) and SEI-Li+ (0.0191mAh per cycle) during consecutive cycles. Benefiting from the efficient Li plating/stripping manner, the assembled anode-free Cu|LiFePO4 (2.7mAh cm-2 ) coin and pouch cells exhibit impressive capacity retention of 43.8% and 41.6% after 150 cycles, respectively, albeit with no optimization on the test conditions. This work provides guidelines into the targeted interfacial design of high-efficiency working Li anodes, aiming to pave the way for the practical deployment of high-energy-density Li metal batteries.

Porphyrazines with annulated diazepine rings. 6. Synthesis and properties of the alkyl substituted derivative - MgII complex of tetrakis-2,3-(5,7-di-tert-butyl-6H-1,4-diazepino)porphyrazine

Novel MgII porphyrazine 3 bearing four appended seven-membered tert-butyl substituted 1,4-diazepine rings was prepared via Linstead macrocyclization of 5,7-di-tert-butyl-6[Formula: see text]-1,4-diazepine-2,3-dicarbonitrile 2, obtained by condensation of diaminomaleonitrile and 2,2,6,6-tetramethylheptanedione-3,5 (1) in anhydrous ethanol in the presence of P2O5. The structure of the dinitrile precursor 2 was established by single crystal X-ray work. 1H NMR study revealed that the 1,4-diazepine ring is present in the 6[Formula: see text] tautomeric form both in the dinitrile precursor 2 and the MgII complex 3. The inversion of the tert-butyl substituted diazepine ring occurs more easily than in the case of aryl and alkenyl substituted species. Although porphyrazine 3exhibit some tendency to aggregation in low-polar solvents the presence of bulky tert-butyl substituents stabilizes the monomeric form and hinders formation of H-bonded dimers characteristic for aryl and styryl substituted analogues.

Cost-Effective Strategy for the Synthesis of Air-Stable CH3NH3PbX3 (X = Cl, Br, and I) Quantum Dots with Bright Emission.

Lead halide perovskite quantum dots (QDs) are known as prospective optoelectronic device materials because of their excellent luminescence, extraordinary photoelectric performance, and specific octahedron framework. Herein, we report a cost-effective approach for synthesizing highly stable CH3NH3PbBr3 QDs in low-polarity binary solvents without nitrogen protection. The CH3NH3PbBr3 QDs are tunable from 1.2 to 4.2 nm by adjusting the proportion of oleic acid and oleylamine as capping ligands. The photoluminescence quantum yield of CH3NH3PbBr3 QDs can reach 87.4%. The fluorescence can maintain over 80% of its earliest emission intensity under the atmosphere after 5 days, which is much better than that (∼10%) of QDs with ligand-assisted reprecipitation. The possible reaction mechanism of preparing CH3NH3PbBr3 QDs was also addressed. Notably, such a strategy can be applied extensively in the preparation of other lead halide perovskite QDs. Furthermore, the as-prepared thick PMMA-coated CH3NH3PbBr3 QDs were further conjoined with a red luminescence powder on a blue InGaN chip to obtain a powerful efficiency (45.4 lm W-1) warm white light-emitting diode.

Selective synthesis of high-added value chemicals from α-pinene epoxide and limonene epoxide isomerization over mesostructured catalysts: Effect of the metal loading and solvent

Isomerization of α-pinene epoxide was performed over several Fe or Cu supported on MCM-41 and SBA-15 catalysts. The effect of the metal loading and polarity of the solvent on substrate conversion and selectivity was analyzed. It was found that materials containing Fe are more active but less selective to campholenic aldehyde and trans-carveol than materials with Cu, difference that was related with the size of the metal oxide particles and strength/type of the acid sites. An increasing of the solvent polarity decreases formation of campholenic aldehyde, the most desirable compound from α-pinene epoxide. Also, it was showed that trans-carveol is an intermediate in the production of p-cymene. Selectivity to campholenic aldehyde up to 82% can be achieved over Cu/MCM-41 as heterogeneous catalyst at soft reaction conditions (70 °C, 2.5 h, 25 mg, 750 rpm, toluene as solvent). From limonene epoxide isomerization over Fe/SBA-15, dihydrocarvone and limonene-1,2-diol production depended on the type of solvent. An increasing of polarity of the solvent, appears to increase selectivity to dihydrocarvone while limonene-1,2-diol is favored with solvents of lower polarity (mainly cyclohexane and hexane). Reuse of Fe materials were also tested for both monoterpene epoxides showing that Fe supported on MCM-41 and SBA-15 can be used several times (up to 5 times) without any loss of catalytic activity for the synthesis of campholenic aldehyde from α-pinene epoxide and dihydrocarvone (and limonene-1,2-diol) from limonene epoxide.

DABCO as a potential catalyst for the CO2 fixation: A density functional theory and ab initio molecular dynamics study

AbstractIncreasing concentration of CO2 in the atmosphere is a great concern today. One of the best ways to overcome this challenge is to convert CO2 into useful chemicals. Referring to the difficulties posed by the conversion of CO2 into value‐added chemicals, an attempt has been made to investigate 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential cost‐effective organic catalyst in the present work. A fixation reaction of CO2 with oxirane was chosen to be as a prototypal model in the presence of DABCO catalyst. The density functional theory (DFT) and ab initio molecular dynamics (AIMD) studies were conducted, which clearly show that the DABCO molecule efficiently catalyzes the fixation reaction via simultaneous activation of both oxirane and CO2 concertedly. The effect of polar and nonpolar solvents on the reaction was also investigated. The low polarity solvents were found to be the appropriate medium for the reaction. Further, the DFT results clearly reveal that the catalytic activity of the DABCO molecule increases upon the substitution of oxirane.

Effects of Strength Additives on the Properties of High Bulk Pulp Mold

The bulkier structure would be one of the most important properties of the pulp mold as promising packaging materials. The low-polar solvent mixing at the forming process of wet pulp mold manufacturing resulted in the bulkier pulp mold. But the strength properties of the pulp mold would decreased. In this study, the effects of various types of paper strength additives on the strength of the pulp mold were evaluated depending on the forming condition in order to improving the strength properties of the bulker pulp mold. The dry strength and the wet strength of pulp mold were increased by the addition of the strength additives, but the effects of the additives were relatively lower in case of the low-polar solvent mixing condition. The application of the strength additives resulted in the higher increase in the strength properties of the pulp mold made of ONP than those of the pulp mold made of unbeaten BKP. The dry elongation of the pulp mold made at the low-polar solvent mixing condition showed the higher value of the pulp mold made at the water 100% condition. Although the strength properties of the pulp mold made at the low-polar solvent mixing condition were decreased, the application of the strength additives on the pulp mold could compensate for the reduction in the strength properties of the bulkier pulp mold.

Rewritable PEDOT Film Based on Water-Writing and Electroerasing.

Rewritable paper has greatly promoted the sustainable development of society. However, the hydrophilicity/lipophilicity of the poly(3,4-ethylenedioxythiophene) (PEDOT) film limits its application as the rewritable paper. Herein, we constructed a repeatable writing/erasing pattern on a PEDOT film (rewritable PEDOT paper) by combining wettability control, water-induced dedoping, and an electrochemical redox reaction. The treatment with a medium-polarity/high-volatility solvent (MP/HVS) adjusted the wettability of the PEDOT film (water contact angle increased from 6.5° to 146.2°), contributing to the formation of a hydrophobic writable substrate. The treatment with a high-polarity solvent (HPS) induced the dedoping of anions in the PEDOT chain, resulting in the film's color changed from blue to purple and serving as a writing process. The intrinsic electrochemical redox (elimination of color change by doping/dedoping of lithium ions in the PEDOT chain) of the PEDOT film enabled the erasing process. This writing/erasing process can be repeated at least 10 times. The patterned PEDOT film maintained excellent stability to standing diverse solvents (low-polarity solvent (LPS) and MP/HVS), high temperatures (350 °C), and irradiation of different light wavelengths (wavelengths of 365, 380, 460, 520, and 645 nm). Additionally, the conductivity of the PEDOT film was quantitatively measured (impedance: LPS, increased 8.84%; MP/HVS, decreased 6.67%; and HPS, increased 27.97%) by fabricating a micropatterned PEDOT electrode. This work will provide a method for the fabrication of PEDOT-based optoelectronic functional materials.

The Role of Counterions in Intermolecular Radical Coupling of Ru-bda Catalysts

Intermolecular radical coupling (also interaction of two metal centers I2M) is one of the main mechanisms for O–O bond formation in water oxidation catalysts. For Ru(bda)L2 (H2bda = 2,2′-bipyridine-6,6′-dicarboxylate, L = pyridine or similar nitrogen containing heterocyclic ligands) catalysts a significant driving force in water solution is the hydrophobic effects driven by the solvent. The same catalyst has been successfully employed to generate N2 from ammonia, also via I2M, but here the solvent was acetonitrile where hydrophobic effects are absent. We used a classical force field for the key intermediate [RuVIN(bda)(py)2]+ to simulate the dimerization free energy by calculation of the potential mean force, in both water and acetonitrile to understand the differences and similarities. In both solvents the complex dimerizes with similar free energy profiles. In water the complexes are essentially free cations with limited ion paring, while in acetonitrile the ion-pairing is much more significant. This ion-pairing leads to significant screening of the charges, making dimerization possible despite lower solvent polarity that could lead to repulsion between the charged complexes. In water the lower ion pairing is compensated by the hydrophobic effect leading to favorable dimerization despite repulsion of the charges. A hypothetical doubly charged [RuVIIN(bda)py2]2+ was also studied for deeper understanding of the charge effect. Despite the double charge the complexes only dimerized favorably in the lower dielectric solvent acetonitrile, while in water the separated state is more stable. In the doubly charged catalyst the effect of ion-pairing is even more pronounced in acetonitrile where it is fully paired similar to the 1+ complex, while in water the separation of the ions leads to greater repulsion between the two catalysts, which prevents dimerization.Graphic

Neoxanthin in young vegetable leaves prevents fat accumulation in differentiated adipocytes.

The present study aimed to investigate the effect of young leaves on fat accumulation in differentiated 3T3-L1 adipocytes. A potent preventive effect on fat accumulation was observed in fractions of young leaves of spinach, beet, and arugula extracted with a low-polarity solvent (hexane:acetone:ethanol:toluene=10:6:7:6). This effect was seemingly associated with the leaf carotenoid content, including lutein, β-carotene, and neoxanthin. Among these, only neoxanthin, with the characteristic structure of 5,6-monoepoxide and an allenic bond, significantly prevented fat accumulation in a dose-dependent manner. The preventive effect and carotenoid content, including neoxanthin, of these young leaves did not differ from those of the corresponding adult leaves. Therefore, our study demonstrated that young vegetable leaves, such as spinach, beet, and arugula leaves, contained neoxanthin, which prevented fat accumulation in adipocytes in vitro. In the future, the effectiveness of such young leaves and neoxanthin should be investigated in vivo.

Synthesis, And Studying Effect Of a Solvent On The 1H-NMR Chemical Shifts of 4-Azido-N-(6-chloro-3-pyridazinyl) Benzenesulfonamide

The compound 4-Azido-N-(6-chloro-3-pyridazinyl)benzenesulfonamide was synthesized and studied using FTIR, and 1H-NMR . The influence of a solvent on the experimental 1H-NMR chemical shifts of title compound is discussed. Small chemical shift Δδ < 0.1 ppm were observed when switching from DMSO-d6 to CD3OD. Record a marked change in chemical shifts valeues Δδ > 0.3 ppm when transform from high-polar solvents (DMSO-d6,and CD3OD) to low-polar solvent (CDCl3). The 1H-NMR chemical shifts of C2-H and C6-H were shown to have excellent linear correlation with the dielectric constants of the solvents DMSO-d6, CD3OD,and CDCl3 (r = 0.995). The 1H-NMR chemical shifts of C18-H shows a perfect relationship with solvatochromic parameter β (r = 0.999).

Brønsted acid-catalyzed 1,4-addition of 1,3,5-trimethoxybenzene to maleimides and acrylates

Several Brønsted acids were investigated as catalysts for 1,4-additions of 1,3,5-trimethoxybenzene to maleimides. Among the acids tested, trifluoromethanesulfonic acid in low polar solvents such as toluene and 1,2-dichloroethane was found to show high reactivity, enabling preparation of 3-(2,4,6-trimethoxyphenyl)succinimides. 1,4-Additions of 1,3,5-trimethoxybenzene to acrylates were also realized by a catalytic amount of trifluoromethanesulfonic acid in toluene.

Mechanism and Selectivity Control in Ni- and Pd-Catalyzed Cross-Couplings Involving Carbon-Oxygen Bond Activation.

Transition-metal-catalyzed C-O bond activation provides a useful strategy for utilizing alcohol- and phenol-derived electrophiles in cross-coupling reactions, which has become a research field of active and growing interest in organic chemistry. The synergy between computation and experiment elucidated the mechanistic model and controlling factors of selectivities in these transformations, leading to advances in innovative C-O bond activation and functionalization methods.Toward the rational design of C-O bond activation, our collaborations with the Jarvo group bridged the mechanistic models of C(sp2)-O and C(sp3)-O bond activations. We found that the nickel catalyst cleaves the benzylic and allylic C(sp3)-O bonds via two general mechanisms: the stereoinvertive SN2 back-side attack model and the stereoretentive chelation-assisted model. These two models control the stereochemistry in a wide array of stereospecific Ni-catalyzed cross-coupling reactions with benzylic or allylic alcohol derivatives. Because of the catalyst distortion, the ligands can differentiate the competing stereospecific C(sp3)-O bond activations. The PCy3 ligand interacts with nickel mainly through σ-donation, and the Ni(PCy3) catalyst can undergo facile bending of the substrate-nickel-ligand angle, which favors the stereoretentive benzylic C-O bond activation. The N-heterocyclic carbene SIMes ligand has additional d(metal)-p(ligand) back-donation with nickel, which leads to an extra energy penalty for the same angle bending. This results in the preference of stereoinvertive benzylic C-O bond activation under Ni/SIMes catalysis. In addition to ligand control, a Lewis acid can increase the selectivity for stereoinvertive C(sp3)-O activation by stabilizing the SN2 back-side attack transition state. The oxygen leaving group complexes with the MgI2 Lewis acid in the stereoinvertive activation, leading to the exclusive stereoinvertive Kumada coupling of benzylic ethers. We also identified that the competing C(sp3)-O bond activation models have noticeable differences in charge separation. This leads to the solvent polarity control of the stereospecificity in C(sp3)-O activations. Low-polarity solvents favor the neutral stereoretentive C-O bond activation, while high-polarity solvents favor the zwitterionic stereoinvertive cleavage.In sharp contrast to the nickel catalysts, the C(sp2)-O bond activation under palladium catalysis mainly proceeds via the classic three-membered ring oxidative addition mechanism instead of the chelation-assisted mechanism. This is due to the lower oxophilicity of palladium, which disfavors the oxygen coordination in the chelation-assisted-type activation. The three-membered ring activation model selectively cleaves the weak C-O bond, resulting in the exclusive chemoselectivity of acyl C-O bond activation in Pd-catalyzed cross-coupling reactions with aryl carboxylic acid derivatives. This explains the overall acylation in the Pd-catalyzed Suzuki-Miyaura coupling with aryl esters. In collaboration with the Szostak group, we revealed that the three-membered ring model applies in the Pd-catalyzed C-O bond activation of carboxylic acid anhydride, which stimulated the development of a series of Pd-catalyzed decarbonylative functionalizations of aryl carboxylic acids.

π‐Extended Push‐Pull‐Type Bicyclic Fluorophores Based on Quinoline and Naphthyridine Frameworks with an Iminophosphorane Fragment

AbstractEmissive quinoline and naphthyridine derivatives, bearing an iminophosphorane (IPP) fragment as an electron‐donating group and two trifluoromethyl groups as electron‐withdrawing groups, were prepared as electron push‐pull‐type bicyclic fluorophores: quinoline‐IPP (1) and naphthyridine‐IPP (2). Compared to those of the precursor bicyclic amines without the IPP moiety, the fluorescence quantum yields (Φf) of 1 and 2 were considerably higher, not only in low polarity solvents but also polar solvents. Moreover, the molar absorption coefficients (ϵ) were enhanced; thus, 1 and 2 are fluorophores with relatively high brightness (Φf×ϵ). Using density functional theory calculations, the t indices were calculated, and these reveal that locally excited character is dominant in both molecules. Because of the sterically bulky IPP fragments, 1 and 2 emitted with moderate Φf values, even in the solid state. Further, by exploiting the low crystallinity of 1 and 2, emissive amorphous thin films were prepared.

Direct Arylation Polycondensation toward Water/Alcohol-Soluble Conjugated Polymers: Influence of Side Chain Functional Groups.

Direct arylation of 2,7-dibromofluorene with n-octyl, 6-diethoxylphosphorylhexyl, 6-(N,N-diethylamino)hexyl or 6-bromohexyl side chains and 1,2,4,5-tetrafluorobenzene (TFB) were conducted to investigate the effect of side chain functional groups on the coupling, and the resulting TFB-substituted fluorene derivatives were used as C-H monomers for the synthesis of water/alcohol soluble conjugated polymers (WSCPs) by direct arylation polycondensation (DArP). The direct arylation and DArP of the monomers carrying phosphonate and amino groups went on smoothly in typical DArP conditions, that is, Pd(OAc)2/PtBu2Me-HBF4/base/DMAc and Pd2(dba)3·CHCl3/P(o-MeOPh)3/pivalic acid/base/THF, and high molecular weight polymers with these groups were successfully synthesized. However, for fluorene-monomers with bromohexyl side chains, the target products could not be obtained from the above conditions but could be prepared in the absence of carboxylic acid additives in low polar solvents. With the above DArP-made polymers as cathode interfacial layers, high performance organic solar cells (OSCs) were successfully fabricated.

The influence of medium polarity on the kinetics and mechanism of interaction of aliphatic nitroxides with hydroperoxyl radicals

The mechanism of 1,2-substituted ethylene and 1,4-substituted butadiene oxidation with cyclic multiple chain termination by nitroxide radicals has been confirmed using a large set of nitroxides of piperidine, pyrroline, pyrrolidine and imidazoline series. This mechanism includes hydroperoxyl radicals as chain propagating agents and is realized both in non-polar and in polar media. The solvent effect on the rate constant of nitroxide and hydroperoxide radicals interaction is explained by the specific solvation of $${\text{HO}}_{{2}}^{{{ \bullet }}}$$ radicals. An additional effect in high dielectric constant media can be provided by the nonspecific solvation of nitroxide radicals. In low polar solvents the reactivity of > NO• is almost completely determined by > NO–H bond energy of hydroxylamine.

Superalkali-Alkalide Interactions and Ion Pairing in Low-Polarity Solvents.

The nature of anionic alkali metals in solution is traditionally thought to be “gaslike” and unperturbed. In contrast to this noninteracting picture, we present experimental and computational data herein that support ion pairing in alkalide solutions. Concentration dependent ionic conductivity, dielectric spectroscopy, and neutron scattering results are consistent with the presence of superalkali–alkalide ion pairs in solution, whose stability and properties have been further investigated by DFT calculations. Our temperature dependent alkali metal NMR measurements reveal that the dynamics of the alkalide species is both reversible and thermally activated suggesting a complicated exchange process for the ion paired species. The results of this study go beyond a picture of alkalides being a “gaslike” anion in solution and highlight the significance of the interaction of the alkalide with its complex countercation (superalkali).

Polarity-Tolerant Chloride Binding in Foldamer Capsules by Programmed Solvent-Exclusion

Persistent anion binding in a wide range of solution environments is a key challenge that continues to motivate and demand new strategies in synthetic receptor design. Though strong binding in low-polarity solvents has become routine, our ability to maintain high affinities in high-polarity solvents has not yet reached the standard set by nature. Anions are bound and transported regularly in aqueous environments by proteins that use secondary and tertiary structure to isolate anion binding sites from water. Inspired by this principle of solvent exclusion, we created a sequence-defined foldameric capsule whose global minimum conformation displays a helical folded state and is preorganized for 1:1 anion complexation. The high stability of the folded geometry and its ability to exclude solvent were supported by solid-state and solution phase studies. This capsule then withstood a 4-fold increase in solvent dielectric constant (εr) from dichloromethane (9) to acetonitrile (36) while maintaining a high and solvent-independent affinity of 105 M-1; ΔG ∼ 28 kJ mol-1. This behavior is unusual. More typical of solvent-dependent behavior, Cl- affinities were seen to plummet in control compounds, such as aryl-triazole macrocycles and pentads, with their solvent-exposed binding cavities susceptible to dielectric screening. Finally, dimethyl sulfoxide denatures the foldamer by putative solvent binding, which then lowers the foldamer's Cl- affinity to normal levels. The design of this capsule demonstrates a new prototype for the development of potent receptors that can operate in polar solvents and has the potential to help manage hydrophilic anions present in the hydrosphere and biosphere.

Facile access to furo[2′,3′:4,5]pyrido[3,2,1-jk]carbazol-5-ones as blue emitters: photophysical, electrochemical, thermal and DFT studies

A series of thermally stable (up to ≤339°C) and blue fluorescent furo[2′,3′:4,5]pyrido[3,2,1-jk]carbazol-5-ones (FPCOs) with high quantum yields (Ø ≥ 0.75) are reported. These hybrid scaffolds have been synthesized from a bunch of Morita‐Baylis‐Hillman acetate of nitroalkenes and 4-hydroxy-6H-pyrido[3,2,1-jk]carbazol-6-one (HPCO) promoted by DABCO as an organobase at room temperature. All the new chemical structures were assigned by their spectroscopic techniques such as FT-IR, 1H NMR and 13C NMR, HRMS. The solvatochromic studies of targeted scaffolds exhibited blue shifts in absorption and emission spectra with increasing the polarity of solvents. Interestingly, higher quantum yields were also obtained in case of low polar solvents as well as products containing electron-donating groups. The density functional theory calculations indicated that electron-donating substituents led to the lower HOMO-LUMO gap, resulting in bathochromic shifts in absorption spectra. Moreover, chemical hardness, global softness and chemical potential descriptors of compounds are well-estimated. The nature of electronic transition of synthesized scaffolds was well addressed by TD-DFT calculations. In addition, by using NBO and surface analysis calculations, the most nucleophilic and electrophilic sites of title scaffolds were assigned. Interestingly, the cyclic voltammograms of all the FCPOs were shown only one irreversible reduction peak values (-0.62 V to -0.73 V). Therefore, promising charge carrier properties, good thermal robustness and electrochemical stability would make them potential candidates for electronic devices.

Robust and impermeable metal shell microcapsules for one-component self-healing coatings

Metal shell microcapsules containing liquid 4,4′-bis-methylene cyclohexane diisocyanate (HMDI) were successfully synthesized by plating chemically a layer of Ni-P alloy on microcapsules surfaces. The metal shell occupied around 66.0 wt% of final microcapsules, providing great potential to improve microcapsules robustness. Final microcapsules with diameters of 184.3 ± 41.7 µm had a core fraction of 22.4 ± 0.6 wt%. The final microcapsule shells with a total thickness of 7.4 ± 0.4 µm was a three-layered structure, which comprised of an outer-layered Ni-P shell with a thickness of 5.5 ± 0.2 µm, a medium-layered PUF shell with a thickness of 369.0 ± 21.0 nm, and an inner-layered polyurea shell with a thickness of 1.7 ± 0.2 µm. More interestingly, final microcapsules remained stable core fraction and morphologies in most regular solvents including low polar organic solvents, high polar organic solvents, and water. The shell strength of final microcapsules was 28.5 ± 10.3 MPa, comparing with 6.6 ± 2.5 MPa of polymer shells. Moreover, the modulus of epoxy composites was stable relatively with microcapsules concentrations. Scratched self-healing epoxy coatings showed satisfactory anticorrosion performance in salty water (1 M).

ASSESSMENT OF PHYTOCHEMICALS AND IN VITRO ANTIOXIDANT, ANTI-INFLAMMATORY ACTIVITY OF SARCOSTEMMA BRUNONIANUM WIGHT AND ARN

Objective: Sarcostemma brunonianum Wight and Arn is a potential medicinal plant belonging to Asclepiadaceae. Bioactive constituents of the plant support the application of treating various ailments in the traditional system of medicine. The study aims to determine the presence of various phytoconstituents in stem, root, and flowers.
 Methods: Hot percolation method was carried out to obtain crude extracts using different solvent systems from low polar-high polar solvents ranging from petroleum ether, chloroform, (mid-polar) ethyl acetate, methanol and water. Estimation of total phenols, tannins and In vitro antioxidant, anti-inflammatory activities were evaluated for the determination of potential pharmaceutical drugs.
 Results: The results revealed the presence of some phytoconstituents such as phenols, tannins, glycosides, gums and mucilages. Ascorbic acid, BSA, Rutin and Gallic acid were used as the reference standard. The total phenolic content was found to be high in stem methanol extract 440.84±69.99 mg/g Gallic acid equivalent, whereas the tannin content was 291.78±4.68 mg/g GAE. The result proves that the S. brunonianum stem methanol extract possesses antioxidant and anti-inflammatory activities when compared to reference standards. In vitro, Nitric oxide scavenging activity of stem showed a maximum % of inhibition in methanol stem extract (24.39µg/ml) and anti-inflammatory activity maximum inhibition was found to be (55.56 %) in stem methanol and flower(53.62 %). The IC50 (concentration required for 50% inhibition) was also calculated for the DPPH radical model.
 Conclusion: This study results proclaims and justifies the role of folklore medicinal plant S. brunonianum in the treatment of inflammatory-related ailments and can be recommended for an effective drug.