New analogues of butylated hydroxytoluene as anti-inflammatory and antioxidant agents

Gabapentin Antioxidant Derivatives with Anti-Inflammatory and Neuroprotective Potency

Aims:

The aim of this work is to investigate the antioxidant and anti-inflammatory potency of novel gabapentin derivatives, which could be proven useful as neuroprotective agents.

Background:

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders worldwide. Due to its multi-factorial character, no effective treatment has been obtained yet. In this direction, the multi-targeting compounds approach could be useful for the development of novel, more effective drugs against AD. Oxidative stress and inflammation are highly involved in the progression of neurodegeneration, while gabapentin has been investigated for the treatment of behavioral symptoms in AD.

Objective:

In this work, derivatives of cinnamic acid, Trolox, and 3,5-di-tertbutyl-4-hydroxybenzoic acid amidated with gabapentin methyl ester were designed and studied. Compounds with these structural characteristics are expected to act in various biochemical pathways, affecting neurodegenerative processes.

Methods:

The designed compounds were synthesized with classical amidation methods, purified by flash column chromatography, and identified spectrometrically (1H-NMR and 13C-NMR). Their purity was determined by CHN elemental analysis. They were tested in vitro for their antioxidant and antiinflammatory properties and for their inhibitory effect on acetylcholinesterase. Their in vivo antiinflammatory activity was also tested.

Results:

Molecules that incorporated antioxidant moiety possessed inhibitory activity against rat microsomal membrane lipid peroxidation and oxidative protein glycation, as well as radical scavenging activity. Moreover, most of them presented moderate inhibition towards lipoxygenase (up to 51% at 100μΜ) and acetylcholinesterase (AchE) (IC50 up to 274μΜ) activities. Finally, all synthesized compounds presented in vivo anti-inflammatory activity, decreasing carrageenan-induced rat paw edema up to 53%, and some of them could inhibit cyclooxygenase significantly.

Conclusion:

These results indicate that the designed compounds could be proven useful as multitargeting molecules against AD since they affect various biochemical pathways associated with neurodegeneration. Thus, more effective drugs can be obtained, and the possible adverse effects of drug combinations can be limited.

Butylated hydroxyl-toluene, 2,4-Di-tert-butylphenol, and phytol of Chlorella sp. protect the PC12 cell line against H2O2-induced neurotoxicity

Oxidative stress is considered the main cause of cellular damage in a number of neurodegenerative disorders. One suitable ways to prevent cell damage is the use of the exogenous antioxidant capacity of natural products, such as microalgae. In the present study, four microalgae extracts, isolated from the Persian Gulf, were screened to analyze their potential antioxidant activity and free radical scavenging using ABTS, DPPH, and FRAP methods. The methanolic extracts (D1M) of green microalgae derived from Chlorella sp. exhibited potent free radical scavenging activity. In order to characterize microalgae species, microscopic observations and analysis of the expression of 18S rRNA were performed. The antioxidant and neuroprotective effects of D1M on H₂O₂-induced toxicity in PC12 cells were investigated. The results demonstrated that D1M significantly decreased the release of nitric oxide (NO), formation of intracellular reactive oxygen species (ROS), and the level of malondialdehyde (MDA), whereas it enhanced the content of glutathione (GSH), and activity of heme oxygenase 1 (HO-1), NAD(P)H: quinone oxidoreductase 1 (NQO1), and catalase (CAT) in PC12 cells exposed to H₂O₂. The pretreatment of D1M improved cell viability as measured by the MTT assay and invert microscopy, reduced cell apoptosis as examined by flow cytometry analysis, increased mitochondrial membrane potential (MMP), and diminished caspase-3 activity. The GC/MS analysis revealed that D1M ingredients have powerful antioxidant and anti-inflammatory compounds, such as butylated hydroxytoluene (BHT), 2,4-di-tert-butyl-phenol (2,4-DTBP), and phytol. These results suggested that Chlorella sp. extracts have strong potential to be applied as neuroprotective agents, for the treatment of neurodegenerative disorders.

Design of Multifaceted Antioxidants: Shifting towards Anti-Inflammatory and Antihyperlipidemic Activity

Oxidative stress and inflammation are two conditions that coexist in many multifactorial diseases such as atherosclerosis and neurodegeneration. Thus, the design of multifunctional compounds that can concurrently tackle two or more therapeutic targets is an appealing approach. In this study, the basic NSAID structure was fused with the antioxidant moieties 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHB), its reduced alcohol 3,5-di-tert-butyl- 4-hydroxybenzyl alcohol (BHBA), or 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), a hydrophilic analogue of α-tocopherol. Machine learning algorithms were utilized to validate the potential dual effect (anti-inflammatory and antioxidant) of the designed analogues. Derivatives 1–17 were synthesized by known esterification methods, with good to excellent yields, and were pharmacologically evaluated both in vitro and in vivo for their antioxidant and anti-inflammatory activity, whereas selected compounds were also tested in an in vivo hyperlipidemia protocol. Furthermore, the activity/binding affinity of the new compounds for lipoxygenase-3 (LOX-3) was studied not only in vitro but also via molecular docking simulations. Experimental results demonstrated that the antioxidant and anti-inflammatory activities of the new fused molecules were increased compared to the parent molecules, while molecular docking simulations validated the improved activity and revealed the binding mode of the most potent inhibitors. The purpose of their design was justified by providing a potentially safer and more efficient therapeutic approach for multifactorial diseases.

Antioxidant Serine-(NSAID) Hybrids with Anti-Inflammatory and Hypolipidemic Potency

A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC₅₀ 3.4 μΜ and 2.8 μΜ), several times more potent than the reference Trolox (IC₅₀ 25 μΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37–67% at 150 μmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC₅₀ 13 μΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 μmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

Bi-functional sterically hindered phenol lipid-based delivery systems as potential multi-target agents against Alzheimer's disease via an intranasal route

New lipid-based nanomaterials and multi-target directed ligands (MTDLs) based on sterically hindered phenol, containing a quaternary ammonium moiety (SHP-s-R, with s = 2,3) of varying hydrophobicity (R = CH2Ph and CnH2n+1, with n = 8, 10, 12, 16), have been prepared as potential drugs against Alzheimer's disease (AD). SHP-s-R are inhibitors of human cholinesterases with antioxidant properties. The inhibitory potency of SHP-s-R and selectivity ratio of cholinesterase inhibition were found to significantly depend on the length of the methylene spacer (s) and alkyl chain length. The compound SHP-2-16 showed the best IC50 for human AChE and the highest selectivity, being 30-fold more potent than for human BChE. Molecular modeling of SHP-2-16 binding to human AChE suggests that this compound is a dual binding site inhibitor that interacts with both the peripheral anionic site and catalytic active site. The relationship between self-assembly parameters (CMC, solubilization capacity, aggregation number), antioxidant activity and a toxicological parameter (hemolytic action on human red blood cells) was investigated. Two sterically hindered phenols (SHP-2-Bn and SHP-2-R) were loaded into L-α-phosphatidylcholine (PC) nanoparticles by varying the SHP alkyl chain length. For the brain AChE inhibition assay, PC/SHP-2-Bn/SHP-2-16 nanoparticles were administered to rats intranasally at a dose of 8 mg kg-1. The Morris water maze experiment showed that scopolamine-induced AD-like dementia in rats treated with PC/SHP-2-Bn/SHP-2-16 nanoparticles was significantly reduced. This is the first example of cationic SHP-phospholipid nanoparticles for inhibition of brain cholinesterases realized by the use of intranasal administration. This route has promising potential for the treatment of AD.

POCl3 Mediated Syntheses, Pharmacological Evaluation and Molecular Docking Studies of Some Novel Benzofused Thiazole Derivatives as a Potential Antioxidant and Anti-inflammatory Agents

Background:

The present research work is focused on the development of alternative antioxidant and anti-inflammatory agents. The review of the literature reveals that many benzofused thiazole analogues have been used as lead molecules for the design and development of therapeutic agent, including anticancer, anti-inflammatory, antioxidant and antiviral. The synthesized benzofused thiazole derivatives are evaluated for in vitro antioxidant, anti-inflammatory activities and molecular docking study. Thus, the present research work aims to synthesize benzofused thiazole derivatives and to test their antioxidant and antiinflammatory activities.

Objective:

To design and synthesize an alternative antioxidant and anti-inflammatory agents.

Methods:

The substituted benzofused thiazoles 3a-g were prepared by cyclocondensation reaction of appropriate carboxylic acid with 2-aminothiophenol in POCl3 and heated for about 2-3 h to offer benzofused thiazole derivatives 3a-g. All the newly synthesized compounds were in vitro screened for their anti-inflammatory and antioxidant activities by using a known literature method.

Results:

At the outset, the study of in vitro indicated that the compounds code 3c, 3d and 3e possessed distinct anti-inflammatory activity as compared to a standard reference. All the tested compounds show potential antioxidant activity against one or more reactive (H2O2, DPPH, SO and NO) radical scavenging species. Additionally, docking simulation is further performed to the position of compounds 3d & 3e into the anti-inflammatory active site to determine the probable binding model.

Conclusion:

New anti-inflammatory and antioxidant agents were needed; it has been proved that benzofused thiazole derivatives were 3c, 3d and 3e constituted as an interesting template for the evaluation of new anti-inflammatory agents and an antioxidant’s work also may provide an interesting template for further development.

Active Anti-Inflammatory and Hypolipidemic Derivatives of Lorazepam

Novel derivatives of some non steroidal anti-inflammatory drugs, as well as of the antioxidants α-lipoic acid, trolox and (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid with lorazepam were synthesised by a straightforward method at satisfactory to high yields (40%–93%). All the tested derivatives strongly decreased lipidemic indices in rat plasma after Triton induced hyperlipidaemia. They also reduced acute inflammation and a number of them demonstrated lipoxygenase inhibitory activity. Those compounds acquiring antioxidant moiety were inhibitors of lipid peroxidation and radical scavengers. Therefore, the synthesised compounds may add to the current knowledge about multifunctional agents acting against various disorders implicating inflammation, dyslipidaemia and oxidative stress.

Delivery nanosystems based on sterically hindered phenol derivatives containing a quaternary ammonium moiety: Synthesis, cholinesterase inhibition and antioxidant activity

Multitarget ligands (MTL) based on sterically hindered phenol and containing a quaternary ammonium moiety (SHP-n-Q) were synthesized. These compounds are inhibitors of cholinesterases with antioxidant properties. The inhibitory selectivity is 10-fold potent for BChE than for AChE. IC₅₀ of SHP-n-Q for BChE is 20 μM. SHP-n-Q and their nanosystems exhibit more pronounced antioxidant properties than the synthetic antioxidant (hindered phenol, butylated hydroxytoluene). These compounds display a low hemolytic activity against human red blood cells. The nanotechnological approach was used to increase the bioavailability of SHP-n-Q derivatives. For water soluble SHP-n-Q derivative, the self-assembled structures have a size close to 100 nm at critical association concentration (0.01 M). Mixed cationic liposomes based on l-α-phosphatidylcholine and SHP-n-Q of 100 nm diameter were prepared. The stability, encapsulation efficacy and release from liposomes of a model drug, Rhodamine B, depend on the structure of SHP-n-Q. Cationic liposomes based on l-α-phosphatidylcholine and SHP-3-Q show a good stability in time (1year) and a sustained release (>65 h). They are promising templates for the development of anti-Alzheimer MT-drug delivery systems.

4,5-Diaryl 3(2H)Furanones: Anti-Inflammatory Activity and Influence on Cancer Growth

Apart from their anti-inflammatory action, COX inhibitors have gathered the interest of many scientists due to their potential use for the treatment and prevention of cancer. It has been shown that cyclooxygenase inhibitors restrict cancer cell growth and are able to interact with known antitumor drugs, enhancing their in vitro and in vivo cytotoxicity. The permutation of hydrophilic and hydrophobic aryl groups in COX inhibitors leads to cardinal changes in the biological activity of the compounds. In the present study, thirteen heterocyclic coxib-like 4,5-diarylfuran-3(2H)-ones and their annelated derivatives—phenanthro[9,10-b]furan-3-ones—were synthesized and studied for anti-inflammatory and COX-1/2 inhibitory action and for their cytotoxic activity on the breast cancer (MCF-7) and squamous cell carcinoma (HSC-3) cell lines. The F-derivative of the –SOMe substituted furan-3(2H)-ones exhibited the best activity (COX-1 IC₅₀ = 2.8 μM, anti-inflammatory activity (by carrageenan paw edema model) of 54% (dose 0.01 mmol/kg), and MCF-7 and HSC-3 cytotoxicity with IC₅₀ values of 10 μM and 7.5 μM, respectively). A cytotoxic effect related to the COX-1 inhibitory action was observed and a synergistic effect with the anti-neoplastic drugs gefitinib and 5-fluorouracil was found. A phenanthrene derivative exhibited the best synergistic effect with gefitinib.

Mild and selective silicon-mediated access to enantioenriched 1,2-mercaptoamines and β-amino arylchalcogenides

Metal-free ring opening reactions of activated and unactivated aziridines with different silyl chalcogenides are described.

Docking analysis targeted to the whole enzyme: an application to the prediction of inhibition of PTP1B by thiomorpholine and thiazolyl derivatives

PTP1b is a protein tyrosine phosphatase involved in the inactivation of insulin receptor. Since inhibition of PTP1b may prolong the action of the receptor, PTP1b has become a drug target for the treatment of type II diabetes. In the present study, prediction of inhibition using docking analysis targeted specifically to the active or allosteric site was performed on 87 compounds structurally belonging to 10 different groups. Two groups, consisting of 15 thiomorpholine and 10 thiazolyl derivatives exhibiting the best prediction results, were selected for in vitro evaluation. All thiomorpholines showed inhibitory action (with IC₅₀ = 4-45 μΜ, Ki = 2-23 μM), while only three thiazolyl derivatives showed low inhibition (best IC₅₀ = 18 μΜ, Ki = 9 μΜ). However, free binding energy (E) was in accordance with the IC₅₀ values only for some compounds. Docking analysis targeted to the whole enzyme revealed that the compounds exhibiting IC₅₀ values higher than expected could bind to other peripheral sites with lower free energy, E_o, than when bound to the active/allosteric site. A prediction factor, E- (Σ_Eo × 0.16), which takes into account lower energy binding to peripheral sites, was proposed and was found to correlate well with the IC₅₀ values following an asymmetrical sigmoidal equation with r² = 0.9692.

Docking assisted design of novel 4-adamantanyl-2-thiazolylimino-5-arylidene-4-thiazolidinones as potent NSAIDs

Docking analysis was used to predict the effectiveness of adamantanyl insertion in improving cycloxygenase/lipoxygenase (COX/LOX) inhibitory action of previously tested 2-thiazolylimino-5-arylidene-4-thiazolidinones. The crystal structure data of human 5-LOX (3O8Y), ovine COX-1 (1EQH) and mouse COX-2 (3ln1) were used for docking analysis. All docking calculations were carried out using AutoDock 4.2 software. Following prediction results, 11 adamantanyl derivatives were synthesized and evaluated for biological action. Prediction evaluations correlated well with experimental biological results. Comparison of the novel adamantanyl derivatives with the 2-thiazolylimino-5-arylidene-4-thiazolidinones previously tested showed that insertion of the adamantanyl group led to the production of more potent COX-1 inhibitors, as well as LOX inhibitors (increased activity from 200% to 560%). Five compounds out of the 11 exhibited better activity than naproxen; while nine out of 11 showed better activity than NDGA and seven compounds possessed better anti-inflammatory activity than indomethacin.

Dual antioxidant structures with potent anti-inflammatory, hypolipidemic and cytoprotective properties

Novel amide derivatives of trolox, 3,5-di-tert-butyl-4-hydroxybenzoic acid, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid and cinnamic acid with cysteamine and l-cysteine ethyl ester were synthesised. In four cases, the disulfide derivatives were also isolated and tested. All compounds were examined for antioxidant activity, expressed as their ability to inhibit lipid peroxidation and to scavenge free radicals. They were found to demonstrate up to 17-fold better activity than that of the parent antioxidant acids. They could reduce acute inflammation up to 87%. The most active antioxidant compounds were further tested for their in vivo hypolipidemic effect, which ranged from 47% to 73%, and for their ability to protect the liver against oxidative toxicity caused by high paracetamol dose. The disulfide derivatives of 3,5-di-tert-butyl-4-hydroxybenzoic acid and cinnamic acid had no antioxidant activity and presented equal or lower anti-inflammatory effect than their thiol analogues, indicating that their molecular characteristics may not permit biological barrier penetration.

Development of Antioxidant COX-2 Inhibitors as Radioprotective Agents for Radiation Therapy-A Hypothesis-Driven Review

Radiation therapy (RT) evolved to be a primary treatment modality for cancer patients. Unfortunately, the cure or relief of symptoms is still accompanied by radiation-induced side effects with severe acute and late pathophysiological consequences. Inhibitors of cyclooxygenase-2 (COX-2) are potentially useful in this regard because radioprotection of normal tissue and/or radiosensitizing effects on tumor tissue have been described for several compounds of this structurally diverse class. This review aims to substantiate the hypothesis that antioxidant COX-2 inhibitors are promising radioprotectants because of intercepting radiation-induced oxidative stress and inflammation in normal tissue, especially the vascular system. For this, literature reporting on COX inhibitors exerting radioprotective and/or radiosensitizing action as well as on antioxidant COX inhibitors will be reviewed comprehensively with the aim to find cross-points of both and, by that, stimulate further research in the field of radioprotective agents.

Amides of non-steroidal anti-inflammatory drugs with thiomorpholine can yield hypolipidemic agents with improved anti-inflammatory activity

Novel amides of non steroidal anti-inflammatory drugs (NSAIDs), α-lipoic acid and indole-3-acetic acid with thiomorpholine were synthesised by a simple method and at high yields (60-92%). All the NSAID derivatives highly decreased lipidemic indices in the plasma of Triton treated hyperlipidemic rats. The most potent compound was the indomethacin derivative, which decreased total cholesterol, triglycerides and LDL cholesterol by 73%, 80% and 83%, respectively. They reduced acute inflammation equally or more than most parent acids. Hence, it could be concluded that amides of common NSAIDs with thiomorpholine acquire considerable hypolipidemic potency, while they preserve or augment their anti-inflammatory activity, thus addressing significant risk factors for atherogenesis.

Esters of some non-steroidal anti-inflammatory drugs with cinnamyl alcohol are potent lipoxygenase inhibitors with enhanced anti-inflammatory activity

Novel esters of non steroidal anti-inflammatory drugs, α-lipoic acid and indol-3-acetic acid with cinnamyl alcohol were synthesised by a straightforward method and at high yields (60-98%). They reduced acute inflammation more than the parent acids and are potent inhibitors of soybean lipoxygenase. Selected structures decreased plasma lipidemic indices in Triton-induced hyperlipidemia to rats. Therefore, the synthesised compounds may add to the current knowledge about agents acting against various inflammatory disorders.

Thiomorpholine Derivatives with Hypolipidemic and Antioxidant Activity

A number of thiomorpholine derivatives that are structurally similar to some substituted morpholines possessing antioxidant and hypocholesterolemic activity were synthesized. The new compounds incorporate an antioxidant moiety as the thiomorpholine N-substituent. The derivatives were found to inhibit the ferrous/ascorbate-induced lipid peroxidation of microsomal membrane lipids, with IC50 values as low as 7.5 µΜ. In addition, these compounds demonstrate hypocholesterolemic and hypolipidemic action. The most active compound (5) decreases the triglyceride, total cholesterol, and low-density lipoprotein levels in the plasma of Triton WR-1339-induced hyperlipidemic rats, by 80, 78, and 76%, respectively, at 56 mmol/kg (i.p.). They may also act as squalene synthase inhibitors. The above results indicate that the new molecules may be useful as leads for the design of novel compounds as potentially antiatherogenic factors.

Understanding the chemistry behind the antioxidant activities of butylated hydroxytoluene (BHT): a review

Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized.

Synthesis of new 2,5-di-substituted 1,3,4-oxadiazoles bearing 2,6-di-tert-butylphenol moieties and evaluation of their antioxidant activity

Eleven new 2,6-di-tert-butyl-4-(5-aryl-1,3,4-oxadiazol-2-yl)phenols 5a-k were synthesized by reacting aryl hydrazides with 3,5-di-tert butyl 4-hydroxybenzoic acid in the presence of phosphorus oxychloride. The resulting compounds were characterized based on their IR, ¹H-NMR, ¹³C-NMR, and HRMS data. 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assays were used to test the antioxidant properties of the compounds. Compounds 5f and 5j exhibited significant free-radical scavenging ability in both assays.

Antioxidant and anti-inflammatory activities of Pittocaulon species from México

context: Stems and leaves of Pittocaulon spp. (Asteraceae) are used in Mexican traditional medicine as an anti-inflammatory substance and for the treatment of skin injuries.

OBJECTIVE

This study evaluated the antioxidant activity of methanol (MeOH) and dichloromethane (DC) extracts of five Pittocaulon species.

MATERIALS AND METHODS

DC and MeOH extracts from flowers, roots, and stems of Pittocaulon praecox (Cav.) H. Rob. & Brettell, P. bombycophole (Bullock) H. Rob. & Brettell, P. filare (Mc Vaugh) H. Rob. & Brettell, P. velatum (Greenm.) Rob. & Brettell and P. hintonii H. Rob. & Brettell.

RESULT AND DISCUSSION

In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the flower extracts obtained with MeOH were the most active with IC(50) values ranging from 51.83 ± 4.08 to 154.19 ± 8.39 ppm. In the thiobarbituric acid reactive substances (TBARS) model, the best activity was shown by DC extracts of roots with IC(50) values ranging from 55.54 ± 1.28 to 160.82 ± 5.37 ppm. The MeOH extract of flowers of P. bombycophole had the highest IC(50) value in both DPPH (51.83 ± 4.08 ppm) and TBARS (39.78 ± 1.97 ppm). The samples with the best values in the antioxidant activity assays were evaluated in the anti-inflammatory tests. The DC root extract of P. velatum at a dose of 1 mg/ear produced the greatest reduction (84.96%) of the 2-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema. This extract also reduced the activity of the enzyme myeloperoxidase (MPO) (73.65%) at the same dose. In contrast, DC root extract of this species did not show significant inhibition of the increase in paw edema induced by carrageenan at the doses tested (100 mg/kg).

CONCLUSION

These results support the traditional use of these plants as anti-inflammatory. DC extracts of P. velatum and MeOH extracts of P. bombycophole may be a potential resource of natural anti-inflammatory and antioxidant compounds, respectively. Additional studies must be done to identify the compounds responsible of the activity on these plants and to establish the mechanism of action.

Antioxidant, Antimicrobial and Wound Healing Activities of Boesenbergia rotunda

The ethanolic extract of Boesenbergia rotunda (L.) Mansf. was studied for its wound-healing potential. Since wound healing is interrelated with microbial infection and reactive oxygen species (ROS), this study was conducted to evaluate the antimicrobial and antioxidant activity of B. rotunda. The antimicrobial activity of B. rotunda was studied against six bacterial and two yeast strains using disc diffusion, minimum inhibitory concentration (MIC), and minimum microbicidal concentration (MMC). The B. rotunda extract displayed potential antimicrobial and antifungal activities by inhibiting the Gram-positive bacteria Staphylococcus aureus (ATCC 25923), S. epidermidis, and Bacillus subtilis (ATCC 6633), and the yeasts Candida albicans (ATCC 10231), and Saccharomyces cerevisiae. MIC and MMC values varied from 0.04 to 25 mg/mL and from 0.16 to 25 mg/mL, respectively. The antioxidant activity of B. rotunda was evaluated by measuring the Ferric Reducing/Antioxidant Power (FRAP) and DPPH free radical scavenging activity. The FRAP and DPPH values were 22.2 μM /ug and 76.3 mg/mL, respectively. In the wound-healing studies, the topical application of the B. rotunda extract indicated a significantly increased percentage of wound contraction on day 12 compared with the control group. Histological studies showed the complete epidermis and found collagen fibers and hair follicles in the dermis. The results of the present study support the continued and expanded utilization of B. rotunda in Thai folk medicine.

Amino Acid-derived Protic Ionic Liquids: Physicochemical Properties and Behaviour as Amphiphile Self-assembly Media

The thermal phase transitions and physicochemical properties of a series of 21 amino acid-derived protic ionic liquids and four protic molten salts have been investigated. Structure–property comparisons for this series were investigated for alkyl- and cyclic amino acid cations, and ethoxy and methoxy groups on the cation, combined with nitrate or various carboxylate-containing anions. All the protic fused salts were found to be ‘fragile’. Most of the protic fused salts exhibited a glass transition, with the transition temperatures ranging from –90° to –42°C. Viscosities and conductivities ranged from 0.03 to 15.46 Pa s and 0.02 to 2.20 mS cm–1 at 25°C respectively. The protic ionic liquids alanine methyl ester glycolate, proline methyl ester nitrate, and proline methyl ester glycolate were found to be capable of supporting amphiphile self-assembly. Lamellar or hexagonal liquid crystalline phases were observed with the cationic surfactant hexadecyltrimethylammonium bromide and the non-ionic surfactant Myverol 18–99K.

A convenient synthesis of amino acid methyl esters

A series of amino acid methyl ester hydrochlorides were prepared in good to excellent yields by the room temperature reaction of amino acids with methanol in the presence of trimethylchlorosilane. This method is not only compatible with natural amino acids, but also with other aromatic and aliphatic amino acids.

Synthesis and antioxidant activities of 3,5-dialkoxy-4-hydroxycinnamamides

A series of 3,5-dialkoxy-4-hydroxycinnamamides 6 and 7 was synthesized, and their antioxidant activity was assessed using the thiobarbituric acid reactive substance (TBARS) assay. Interestingly, cinnamamides with longer alkoxy groups on the C-3 and C-5 positions display enhanced inhibition, and most of the compounds in the series tested exhibit excellent lipid peroxidation inhibitory activities. Some cinamamides bearing hexyloxy or 2,6-di-tert-butyl-4-methyl phenol groups have submicromolar inhibitory activities.