Chemotherapy of leishmaniasis. Part VII: synthesis and bioevaluation of substituted terpenyl pyrimidines

Antiplasmodial Activity of β-Ionone and the Effect of the Compound on Amelioration of Anaemia and Oxidative Organ Damage in Mice Infected with Plasmodium berghei

INTRODUCTION

Owing to evolution of parasite strains that are resistant to existing antimalarial drugs, research for novel antimalarial medicines is progressing on numerous fronts.

PURPOSE

Herein, we evaluated the in vivo anti-Plasmodium berghei activity of β-ionone including its ameliorative potential towards P. berghei-associated anaemia and oxidative organ damage.

METHODS

Mice were infected with chloroquine-sensitive strain of P. berghei and then treated with β-ionone at doses of 10 and 20 mg/kg body weight (BW) for seven days. The parasitemia, packed cell volume and redox sensitive biomarkers in the liver, brain and spleen were estimated.

RESULTS

Our result showed that β-ionone, in a dose-dependent fashion, significantly (p < 0.05) repressed the multiplication of P. berghei. More so, the compound, at doses of 10 and 20 mg/kg BW, significantly (p < 0.05) mitigated anaemia and organ damage induced by P. berghei.

CONCLUSION

Overall, the findings demonstrated that β-ionone has antiplasmodial actions and plays a mitigative role against P. berghei-induced anaemia and oxidative organ damage.

β-Ionone represses renal cell carcinoma progression through activating LKB1/AMPK-triggered autophagy

β-Ionone, the end ring analog of β-carotenoids, has been proven to have an antitumor effect in a variety of cancers. In this study, we investigated the impact of β-ionone on renal cell carcinoma (RCC) cell lines (786-O and ACHN) using colony formation assays, flow cytometry analysis, and western blot analysis. We found that β-ionone effectively inhibited the proliferation of RCC cells in vitro, which was also confirmed in a xenograft model. Moreover, we found that β-ionone could induce autophagy, as indicated by LC3 puncta in 786-O and ACHN cell lines and the expression of LC3 in β-ionone-treated RCC cells. To further explore the underlying mechanism, we assessed liver kinase B1/AMP-activated protein kinase (LKB1/AMPK) signaling pathway activity, and the results showed that β-ionone inhibited the proliferation of RCC cells by inducing autophagy via the LKB1/AMPK signaling pathway. In summary, our findings provide a new therapeutic strategy of β-ionone-induced autophagy in RCC.

A review of synthetic bioactive tetrahydro-β-carbolines: A medicinal chemistry perspective

1, 2, 3, 4-Tetrahydro-β-carboline (THβC) scaffold is widespread in many natural products (NPs) and synthetic compounds which show a variety of pharmacological activities. In this article, we reviewed the design, structures and biological characteristics of reported synthetic THβC compounds, and structure and activity relationship (SAR) of them were also discussed. This work might provide a reference for subsequent drug development based on THβC.

Carotenoids and Apocarotenoids in Planta: Their Role in Plant Development, Contribution to the Flavour and Aroma of Fruits and Flowers, and Their Nutraceutical Benefits

Carotenoids and apocarotenoids are diverse classes of compounds found in nature and are important natural pigments, nutraceuticals and flavour/aroma molecules. Improving the quality of crops is important for providing micronutrients to remote communities where dietary variation is often limited. Carotenoids have also been shown to have a significant impact on a number of human diseases, improving the survival rates of some cancers and slowing the progression of neurological illnesses. Furthermore, carotenoid-derived compounds can impact the flavour and aroma of crops and vegetables and are the origin of important developmental, as well as plant resistance compounds required for defence. In this review, we discuss the current research being undertaken to increase carotenoid content in plants and research the benefits to human health and the role of carotenoid derived volatiles on flavour and aroma of fruits and vegetables.

Structural Insights of Three 2,4-Disubstituted Dihydropyrimidine-5-carbonitriles as Potential Dihydrofolate Reductase Inhibitors

In this report, we describe the structural characterization of three 2,4-disubstituted-dihydropyrimidine-5-carbonitrile derivatives, namely 2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-4-propyl-1,6-dihydropyrimidine-5-carbonitrile 1, 4-(2-methylpropyl)-2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-1,6-dihydropyrimidine-5-carbonitrile 2, and 2-[(2-ethoxyethyl)sulfanyl]-6-oxo-4-phenyl-1,6-dihydropyrimidine-5-carbonitrile monohydrate 3. An X-ray diffraction analysis revealed that these compounds were crystallized in the centrosymmetric space groups and adopt an L-shaped conformation. One of the compounds (3) crystallized with a water molecule. A cyclic motif (R₂²(8)) mediated by N–H···O hydrogen bond was formed in compounds 1 and 2, whereas the corresponding motif was not favorable, due to the water molecule, in compound 3. The crystal packing of these compounds was analyzed based on energy frameworks performed at the B3LYP/6-31G(d,p) level of theory. Various inter-contacts were characterized using the Hirshfeld surface and its associated 2D-fingerprint plots. Furthermore, a molecular docking simulation was carried out to assess the inhibitory potential of the title compounds against the human dihydrofolate reductase (DHFR) enzyme.

β-Ionone: Its Occurrence and Biological Function and Metabolic Engineering

β-Ionone is a natural plant volatile compound, and it is the 9,10 and 9′,10′ cleavage product of β-carotene by the carotenoid cleavage dioxygenase. β-Ionone is widely distributed in flowers, fruits, and vegetables. β-Ionone and other apocarotenoids comprise flavors, aromas, pigments, growth regulators, and defense compounds; serve as ecological cues; have roles as insect attractants or repellants, and have antibacterial and fungicidal properties. In recent years, β-ionone has also received increased attention from the biomedical community for its potential as an anticancer treatment and for other human health benefits. However, β-ionone is typically produced at relatively low levels in plants. Thus, expressing plant biosynthetic pathway genes in microbial hosts and engineering the metabolic pathway/host to increase metabolite production is an appealing alternative. In the present review, we discuss β-ionone occurrence, the biological activities of β-ionone, emphasizing insect attractant/repellant activities, and the current strategies and achievements used to reconstruct enzyme pathways in microorganisms in an effort to to attain higher amounts of the desired β-ionone.

Ionone Is More than a Violet's Fragrance: A Review

The term ionone is derived from “iona” (Greek for violet) which refers to the violet scent and “ketone” due to its structure. Ionones can either be chemically synthesized or endogenously produced via asymmetric cleavage of β-carotene by β-carotene oxygenase 2 (BCO2). We recently proposed a possible metabolic pathway for the conversion of α-and β-pinene into α-and β-ionone. The differences between BCO1 and BCO2 suggest a unique physiological role of BCO2; implying that β-ionone (one of BCO2 products) is involved in a prospective biological function. This review focuses on the effects of ionones and the postulated mechanisms or signaling cascades involved mediating these effects. β-Ionone, whether of an endogenous or exogenous origin possesses a range of pharmacological effects including anticancer, chemopreventive, cancer promoting, melanogenesis, anti-inflammatory and antimicrobial actions. β-Ionone mediates these effects via activation of olfactory receptor (OR51E2) and regulation of the activity or expression of cell cycle regulatory proteins, pro-apoptotic and anti-apoptotic proteins, HMG-CoA reductase and pro-inflammatory mediators. α-Ionone and β-ionone derivatives exhibit anti-inflammatory, antimicrobial and anticancer effects, however the corresponding structure activity relationships are still inconclusive. Overall, data demonstrates that ionone is a promising scaffold for cancer, inflammation and infectious disease research and thus is more than simply a violet’s fragrance.

Quantitative analysis of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives, potential DHFR inhibitors: an integrated crystallographic and theoretical study

Two potential bioactive pyrimidine-5-carbonitrile derivatives have been synthesized and characterized by spectroscopic techniques (1H and 13C-NMR) and the three dimensional structures were elucidated by single crystal X-ray diffraction at low temperature (160 K). In both structures, the molecular conformation is locked by an intramolecular C-H⋯C interaction involving the cyano and CH of the thiophene and phenyl rings. The intermolecular interactions were analyzed in a qualitative manner based on the Hirshfeld surface and 2D-fingerprint plots. The results suggest that the phenyl and thiophene moieties have an effect on the crystal packing. For instance, the chalcogen bonds are only preferred in the thiophene derivative. However, both structures uses a common N-H⋯O hydrogen bond motif. Moreover, the structures of 1 and 2 display 1D isostructurality and molecular chains stabilize by intermolecular N-H⋯O and N-H⋯N hydrogen bonds. The nature and extent of different non-covalent interactions were further characterized by the topological parameters derived from the quantum theory of atoms-in-molecules approach. This analysis indicates that apart from N-H⋯O hydrogen bonds, other non-covalent interactions are closed-shell in nature. A strong and linear N-H⋯O hydrogen bond shows intermediate bonding character between shared and closed-shell interactions. The molecular docking analysis suggests that both compounds display potential inhibitory effect against the dihydrofolate reductase (DHFR) enzyme from humans and Staphylococcus aureus.

β-Ionone and its analogs as promising anticancer agents

β-Ionone is an end-ring analog of β-carotenoids which widely distributed in fruit and vegetables. Recent studies have demonstrated anti-proliferative, anti-metastatic and apoptosis induction properties of β-ionone in vitro and in vivo. Also, the studies have focused on investigating the β-ionone action on different types of malignant cells and the possible mechanisms of action. Moreover, the quest of new synthetic β-ionone-based compounds possessing anti-proliferative, anti-metastatic and apoptosis induction activities may enable the discovery of compounds which can be used in combination regimes thus overcoming tumor resistance to conventional anticancer agents. These new agents will also be useful for targeting distinct signaling pathways, to activate selectively mechanisms for apoptosis in cancer cells but devoid of undesirable side effects. In this paper, we reviewed the potentialities of β-ionone and related compounds in cancer prevention and chemotherapy.

Synthesis, antifungal activity, and QSAR studies of 1,6-dihydropyrimidine derivatives

INTRODUCTION

A practical synthesis of pyrimidinone would be very helpful for chemists because pyrimidinone is found in many bioactive natural products and exhibits a wide range of biological properties. The biological significance of pyrimidine derivatives has led us to the synthesis of substituted pyrimidine.

MATERIALS AND METHODS

With the aim of developing potential antimicrobials, new series of 5-cyano-6-oxo-1,6-dihydro-pyrimidine derivatives namely 2-(5-cyano-6-oxo-4-substituted (aryl)-1,6-dihydropyrimidin-2-ylthio)-N-substituted (phenyl) acetamide (C1-C41) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), mass analysis, and proton nuclear magnetic resonance ((1)H NMR). All the compounds were screened for their antifungal activity against Candida albicans (MTCC, 227).

RESULTS AND DISCUSSION

Quantitative structure activity relationship (QSAR) studies of a series of 1,6-dihydro-pyrimidine were carried out to study various structural requirements for fungal inhibition. Various lipophilic, electronic, geometric, and spatial descriptors were correlated with antifungal activity using genetic function approximation. Developed models were found predictive as indicated by their square of predictive regression values (r(2pred)) and their internal and external cross-validation. Study reveals that CHI_3_C, Molecular_SurfaceArea, and Jurs_DPSA_1 contributed significantly to the activity along with some electronic, geometric, and quantum mechanical descriptors.

CONCLUSION

A careful analysis of the antifungal activity data of synthesized compounds revealed that electron withdrawing substitution on N-phenyl acetamide ring of 1,6-dihydropyrimidine moiety possess good activity.

Antitumor, antioxidant and antimicrobial studies of substituted pyridylguanidines

A series of N-pivaloyl-N′-(alkyl/aryl)-N″-pyridylguanidine of general formula C₄H₉CONHC(NR¹R²)NPy have been synthesized and characterized using elemental analysis, FT-IR, multinuclear NMR spectroscopy, and in the case of compounds 7 and 11, by single crystal X-ray diffraction (XRD). The synthesized guanidines were tested for antitumor activities against potato tumor, and showed excellent inhibition against Agrobacterium tumefaciens (AT10)-induced tumor. The antioxidant and antimicrobial activities of these new compounds against various bacterial and fungal strains were also investigated.

Synthesis of novel 6-phenyl-2,4-disubstituted pyrimidine-5-carbonitriles as potential antimicrobial agents

New series of 6-phenyl-2,4-disubstituted pyrimidine-5-carbonitriles namely, 2-substitued thio-6-phenyl-3,4-dihydro-4-oxopyrimidine-5-carbonitriles (5a-d, 6, 7a-d, 8), 2-(4-chlorobenzylthio)-4-chloro-6-phenylpyrimidine-5-carbonitrile (9), 2-(4-chlorobenzylthio)-4-arylthio-6-phenylpyrimidine-5-carbonitriles (10a-d) and 2-(4-chlorobenzylthio)-4-arylamino-6-phenylpyrimidine-5-carbonitriles (11a-d) was synthesized and tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compounds 5b, 5c, 6, 7a, 7b, 7c, 9 and 11a displayed marked antibacterial activity particularly against the tested Gram-positive bacteria, while compounds 6, 7c, 7d and 9 were moderately or weakly active against C. albicans.