Optimization of thiazole analogues of resveratrol for induction of NAD(P)H:quinone reductase 1 (QR1)

A Review on the Mechanism and Structure-activity Relationship of Resveratrol Heteroaryl Analogues

Resveratrol is one of the most interesting naturally-occurring nonflavonoid phenolic compounds with various biological activities, such as anticancer, neuroprotection, antibacterial, and anti-inflammatory. However, there is no clinical usage of resveratrol due to either its poor activity or poor pharmacokinetic properties. Heteroarenes-modified resveratrol is one pathway to improve its biological activities and bioavailability, and form more modification sites. In this review, we present the progress of heteroaryl analogues of resveratrol with promising biological activities in the latest five years, ranging from the synthesis to the structure-activity relationship and mechanism of actions. Finally, introducing heteroarenes into resveratrol is an effective strategy, which focuses on the selectivity of structure-activity relationship in vivo.

The Effects of Novel Triazolopyrimidine Derivatives on H2S Production in Lung and Vascular Tonus in Aorta

INTRODUCTION

Hydrogen sulfide (H2S), known as a third gasotransmitter, is a signaling molecule that plays a regulatory role in physiological and pathophysiological processes. Decreased H2S levels were reported in inflammatory respiratory diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary hypertension. H2S donors or drugs that increase H2S have emerged as novel treatments for inflammatory respiratory diseases. We previously showed that resveratrol (RVT) causes vascular relaxation and antioxidant effects by inducing H2S production. In the current study, we synthesized a new molecule Cpd2, as an RVT analog. We examined the effect of Cpd2 and its precursor chalcone compound (Cpd1) on H2S formation under both healthy and oxidative stress conditions in the lung, as well as vascular relaxation in the aorta.

METHODS

Cpd2 synthesized from Cpd1 with microwaved in basic conditions. H2S formation was measured by H2S biosensor in the mice lungs under both healthy and pyrogallol-induced oxidative stress conditions in the presence/absence of H2S synthesis inhibitor aminooxyacetic acid (AOAA). The effect of compounds on vascular tonus is investigated in mice aorta by DMT myograph.

RESULTS

RVT and Cpd2 significantly increased l-cysteine (l-cys) induced-H2S formation in the lung homogenates of healthy mice, but Cpd1 did not. Superoxide anion generator pyrogallol caused a decrease in H2S levels in mice lungs and Cpd2 restored it. Inhibition of Cpd2-induced H2S formation by AOAA confirmed that Cpd2 increases endogenous H2S formation in both healthy and oxidative stress conditions. Furthermore, we found that both Cpd1 and Cpd2 (10-8-10-4 M) caused vascular relaxation in mice aorta.

DISCUSSION AND CONCLUSION

We found that Cpd2, a newly synthesized RVT analog, is an H2S-inducing molecule and vasorelaxant similar to RVT. Since H2S has antioxidant and anti-inflammatory effects, Cpd2 has a potential for the treatment of respiratory diseases where oxidative stress and decreased H2S levels are present.

Lawesson's reagent promoted deoxygenation of azlactones for the syntheses of 2,4-disubstituted thiazoles

Azlactones and thiazoles are common structural motifs and possess diverse applications. A new method for the efficient and straightforward syntheses of 2,4-disubstituted thiazoles from azlactones has been developed. The reaction proceeded via deoxygenation of azlactones by Lawesson's reagent without metal or external additives. A variety of 2,4-disubstituted thiazoles were synthesized with up to 92% yield. Furthermore, the importance of this methodology was also justified by a gram-scale synthesis.

Synthesis of novel thiazolyl hydrazone derivatives as potent dual monoamine oxidase-aromatase inhibitors

The inhibitory effects of 2-thiazolyl hydrazones on monoamine oxidase enzymes are known for a long time. In this study, a new series of 2-thiazolyl hydrazone derivatives were synthesized starting from 6-methoxy-2-naphthaldehyde. All of the synthesized compounds were investigated in terms of their monoamine oxidase (MAO) inhibitory effects and significant results were found. The results showed that compound 2j potently inhibited MAO-A and MAO-B, while compound 2t strongly and selectively inhibited MAO-B compared to standard drugs. Compounds 2k and 2q exhibited selective and satisfying inhibition on MAO-B. In the aromatase inhibition studies of the compounds, it was determined that compounds 2q and 2u had high inhibitory properties. Molecular docking studies on MAO-A, MAO-B, and aromatase enzymes were carried out for the aforementioned compounds. Additionally, molecular dynamics simulation was studied for compound 2q on MAO-B and aromatase complexes. Finally, the Field-based QSAR study was developed and the structure-activity relationship (SAR) was explained. For the first time, dual inhibitors on MAO and aromatase enzyme were investigated together. The aim of this approach is for finding the potential agents that do not cause the cognitive disorders and may even treat neurodegenerative symptoms, thus, the aim was reached successfully.

Development of Biphenylthiazoles Exhibiting Improved Pharmacokinetics and Potent Activity Against Intracellular Staphylococcus aureus

Exploring the structure-activity relationship (SAR) at the cationic part of arylthiazole antibiotics revealed hydrazine as an active moiety. The main objective of the study is to overcome the inherited toxicity associated with the free hydrazine. A series of hydrocarbon bridges was inserted in between the groups, to separate the two amino groups. Hence, the aminomethylpiperidine-containing analog 16 was identified as a new promising antibacterial agent with efficient antibacterial and pharmacokinetic profiles. Briefly, compound 16 outperformed vancomycin in terms of the antibacterial spectrum against vancomycin-resistant staphylococcal and enterococcal strains with minimum inhibitory concentrations (MICs) ranging from 2 to 4 μg/mL, which is a faster bactericidal mode of action, completely eradicating the high staphylococcal burden within 6-8 h, and it has a unique ability to completely clear intracellular staphylococci. In addition, the initial pharmacokinetic assessment confirmed the high metabolic stability of compound 16 (biological half-life >4 h); it had a good extravascular distribution and maintained a plasma concentration higher than the average MIC value for over 12 h. Moreover, compound 16 significantly reduced MRSA burden in an in vivo MRSA skin infection mouse experiment. These attributes collectively suggest that compound 16 is a good therapeutic candidate for invasive staphylococcal and enterococcal infections. From a mechanistic point of view, compound 16 inhibited undecaprenyl diphosphate phosphatase (UppP) with an IC₅₀ value of 29 μM.

Synthesis and antibacterial evaluation of a novel library of 2-(thiazol-5-yl)-1,3,4-oxadiazole derivatives against methicillin-resistant Staphylococcus aureus (MRSA)

Replacement of the n-butylphenyl moiety in the lipophilic part of the previously reported arylthiazole antibiotics with naphthyl ring amended its activity against vancomycin resistant strains of Staphylococcus aureus. Incorporation of the CN linker connecting the nitrogenous head with thiazole within an oxadiazole ring provided orally available analogs with relatively long half-life. In this article, a set of new twenty-three derivatives of 2-(thiazol-5-yl)-1,3,4-oxadiazole was synthesized combining both structural modifications in one new scaffold with the objectives of enhancing both the pharmacokinetic profile and antibacterial activities vs. malicious microbes. Among the synthesized new compounds, five derivatives showed promising activity with MIC values ranging from 1.95 to 3.90 μg/mL. The guanidinyl-containing naphthylthiazole and N-methylpiperazinyl derivatives (25 &29) were found equipotent as vancomycin against MRSA (2658 RCMB). The other three derivatives (23, 24 and 26) revealed 50% of vancomycin activity.

Screening of potential anti-adipogenic effects of phenolic compounds showing different chemical structure in 3T3-L1 preadipocytes

This study was designed to analyze the anti-adipogenic effect of fifteen phenolic compounds from various chemical groups in 3T3-L1 pre-adipocytes. Cells were treated with 25 μM, 10 μM or 1 μM of apigenin, luteolin, catechin, epicatechin, epigallocatechin, genistein, daizein, naringenin, hesperidin, quercetin, kaempferol, resveratrol, vanillic acid, piceatannol and pterostilbene for 8 days. At 25 μM lipid accumulation was reduced by all the compounds, with the exception of catechin, epicatechin and epigallocatechin. At a dose of 10 μM apigenin, luteolin, naringenin, hesperidin, quercetin and kaempferol induced significant reductions, and at 1 μM only naringenin, hesperidin and quercetin were effective. The expression of c/ebpα was not. C/ebpβ was significantly reduced by genistein and kaempferol, pparγ by genistein and pterostilbene, srebp1c by luteolin, genistein, hesperidin, kaempferol, pterostilbene and vanillic acid, and lpl by kaempferol. In conclusion, the most effective phenolic compounds are naringenin, hesperidin and quercetin. Differences were found in terms of effects on the expression of genes involved in adipogenesis among the analyzed compounds.

Structure-activity relationships and docking studies of synthetic 2-arylindole derivatives determined with aromatase and quinone reductase 1

In our ongoing effort of discovering anticancer and chemopreventive agents, a series of 2-arylindole derivatives were synthesized and evaluated toward aromatase and quinone reductase 1 (QR1). Biological evaluation revealed that several compounds (e.g., 2d, IC50 = 1.61 μM; 21, IC50 = 3.05 μM; and 27, IC50 = 3.34 μM) showed aromatase inhibitory activity with half maximal inhibitory concentration (IC50) values in the low micromolar concentrations. With regard to the QR1 induction activity, 11 exhibited the highest QR1 induction ratio (IR) with a low concentration to double activity (CD) value (IR = 8.34, CD = 2.75 μM), while 7 showed the most potent CD value of 1.12 μM. A dual acting compound 24 showed aromatase inhibition (IC50 = 9.00 μM) as well as QR1 induction (CD = 5.76 μM) activities. Computational docking studies using CDOCKER (Discovery Studio 3.5) provided insight in regard to the potential binding modes of 2-arylindoles within the aromatase active site. Predominantly, the 2-arylindoles preferred binding with the 2-aryl group toward a small hydrophobic pocket within the active site. The C-5 electron withdrawing group on indole was predicted to have an important role and formed a hydrogen bond with Ser478 (OH). Alternatively, meta-pyridyl analogs may orient with the pyridyl 3'-nitrogen coordinating with the heme group.

Effects of resveratrol on drug- and carcinogen-metabolizing enzymes, implications for cancer prevention

Resveratrol is a polyphenol found in grape skins and peanuts that has demonstrated many health benefits including protection against aging, cardiovascular and metabolic disease, neurological decline, and cancer. The anticancer properties of resveratrol have been attributed to a variety of mechanisms, including its general inhibition of phase I metabolism and induction of phase II metabolism. The effects of resveratrol on these enzymes, however, are still unclear, as in vitro evidence often contrasts with animal studies and clinical trials. Reasons for these variances could include the low bioavailability of resveratrol and the effects of resveratrol metabolites. Due to resveratrol's interactions with drug-metabolizing enzymes and drug transporters, individuals concurrently taking pharmacological doses of resveratrol with other supplements or medications could potentially experience nutrient-drug interactions. This review summarizes the known effects of resveratrol and its main metabolites on drug metabolism in order to help characterize which populations might benefit from resveratrol for the prevention of cancer, as well as those that may need to avoid supplementation due to potential drug interactions.

Development of resveratrol-curcumin hybrids as potential therapeutic agents for inflammatory lung diseases

Acute lung injury (ALI) is a major cause of acute respiratory failure in critically-ill patients. Resveratrol and curcumin are proven to have potent anti-inflammatory efficacy, but their clinical application is limited by their metabolic instability. Here, a series of resveratrol and the Mono-carbonyl analogs of curcumin (MCAs) hybrids were designed and synthesized by efficient aldol construction strategy, and then screened for anti-inflammatory activities in vitro and in vivo. The results showed that the majority of analogs effectively inhibited the LPS-induced production of IL-6 and TNF-α. Five analogs, a9, a18, a19, a20 and a24 exhibited excellent anti-inflammatory activity in a dose-dependent manner along with low toxicity in vitro. Structure activity relationship study revealed that the electron-withdrawing groups at meta-position and methoxyl group (OCH₃) at the para position of the phenyl ring were important for anti-inflammatory activities. The most promising compound a18 decreased LPS induced TNF-α, IL-6, IL-12, and IL-33 mRNA expression. Additionally, a18 significantly protected against LPS-induced acute lung injury in the in vivo mouse model. The research of resveratrol and MCAs hybrids could bring insight into the treatment of inflammatory diseases and compound a18 may serve as a lead compound for the development of anti-ALI agents.

Antioxidant and anti-inflammatory properties of 1,2,4-oxadiazole analogs of resveratrol

The chemopreventive properties of resveratrol are ascribed mostly to its antioxidant activity, in particular its scavenging ability for reactive oxygen species (ROS), and to the inhibition of NF-κB pathway which has also been suggested as an important underlying mechanism of its reported properties. In present study, a small library of nine 1,2,4-oxadiazole-based structural analogs of resveratrol were assayed for their antioxidant and anti-inflammatory activities. Several compounds showed significant inhibitory activities against NF-κB and/or ROS production. Compound 2, incorporating two para-hydroxyphenyl moieties connected by the 1,2,4-oxadiazole ring, was the most active, its potency in inhibiting activation of NF-κB and ROS scavenging abilities surpassing that of resveratrol. Additionally, we elucidated the mechanisms underlying the NF-κB inhibitory activity of compound 2. Finally, in contrast to resveratrol, compound 2 significantly reduced the LPS-induced release of pro-inflammatory cytokines, indicating its prominent anti-inflammatory potential.

Recent applications of 1,3-thiazole core structure in the identification of new lead compounds and drug discovery

1,3-Thiazole is one of the most important scaffolds in heterocyclic chemistry and drug design and discovery. It is widely found in diverse pharmacologically active substances and in some naturally-occurring compounds. Thiazole is a versatile building-block for lead generation, and is easily access of diverse derivatives for subsequent lead optimization. In the recent years, many thiazole derivatives have been synthesized and subjected to varied biological activities. In this article we intended to review the most important biological effects of thiazole-based compounds and highlight their roles in new leads identification and drug discovery. This article is also intended to help researches for finding potential future directions on the development of more potent and specific analogs of thiazole-based compounds for various biological targets.

Spongiapyridine and related spongians isolated from an Indonesian Spongia sp

New compounds 18-nor-3,17-dihydroxyspongia-3,13(16),14-trien-2-one (1), 18-nor-3,5,17-trihydroxyspongia-3,13(16),14-trien-2-one (2), and spongiapyridine (3) and the known compound 17-hydroxy-4-epi-spongialactone A (4) were isolated from an Indonesian sponge of the genus Spongia. The structures of 1-3 were deduced by analyses of physical and spectroscopic data. Diterpene 3 is unusual, as the D-ring is a pyridyl ring system rather than the standard δ-lactone. The structure elucidation of this compound was complicated by facile exchange of the axial proton at the C-11 methylene with deuterium from methanol-d4. The isolated compounds were tested for biological activity in a battery of in vitro assays (TNF-α-induced NFκB, LPS-induced iNOS, RXR stimulation, quinone reductase 1 induction, aromatase inhibition, TRPM7 ion channels, and aspartic protease BACE1 inhibition). Norditerpene 2 modestly inhibited aromatase with an IC50 of 34 μM and induced quinone reductase 1 activity with a CD (the concentration needed to double the enzymatic response) of 11.2 μM. The remaining isolates were inactive.

Resveratrol derivatives: a patent review (2009 - 2012)

INTRODUCTION

There is currently a wealth of information on the effects of resveratrol and its derivatives in therapeutic, cosmetic and nutraceutical patent applications. Structure-activity studies of the resveratrol scaffold provide a foundation for the development of new analogs with potent activity or other beneficial properties. Ongoing research has yielded promising results and potential use in the treatment of various diseases.

AREAS COVERED

This review provides analysis of patents published from January 2009 to April 2013. There is a focus on different approaches for the production of resveratrol derivatives, combinations of new derivatives with old drugs, and applications in therapeutic areas, nutraceutical compositions and cosmetics.

EXPERT OPINION

The ability of resveratrol to interact with a disparate array of subcellular targets is uncanny. Nonetheless, even though limited or no toxicity is apparent, the molecule is not a panacea due to lack of potency and issues with bioavailability. Thus, as witnessed by a number of patents, a large assortment of derivatives have been synthesized under the guise of having superior characteristics for treating or preventing various diseases or for use as neutraceutics and cosmetics. Some of these suppositions are probably correct, but evidence-based applications are essentially nil due to a lack of commitment in terms of investing the resources necessary for the conduct of obligatory clinical trials. Current usage is largely based on anecdotes and publicity. Hopefully, at some point in time, it will be possible to follow a standard protocol with a predicable outcome.

Potential chemopreventive activity of a new macrolide antibiotic from a marine-derived Micromonospora sp

Agents capable of inducing phase II enzymes such as quinone reductase 1 (QR1) are known to have the potential of mediating cancer chemopreventive activity. As part of a program to discover novel phase II enzyme-inducing molecules, we identified a marine-derived actinomycete strain (CNJ-878) that exhibited activity with cultured Hepa 1c1c7 cells. Based on this activity, a new macrolide, juvenimicin C (1), as well as 5-O-α-L-rhamnosyltylactone (2), were isolated from the culture broth of a Micromonospora sp. Compound 1 enhanced QR1 enzyme activity and glutathione levels by two-fold with CD values of 10.1 and 27.7 μM, respectively. In addition, glutathione reductase and glutathione peroxidase activities were elevated. This is the first reported member of the macrolide class of antibiotics found to mediate these responses.