Design, Synthesis and Biological Activity Evaluation of S-Substituted 1H-5-Mercapto-1,2,4-Triazole Derivatives as Antiproliferative Agents in Colorectal Cancer

Colon cancer is a widespread pathology with complex biochemical etiology based on a significant number of intracellular signaling pathways that play important roles in carcinogenesis, tumor proliferation and metastasis. These pathways function due to the action of key enzymes that can be used as targets for new anticancer drug development. Herein we report the synthesis and biological antiproliferative evaluation of a series of novel S-substituted 1H-3-R-5-mercapto-1,2,4-triazoles, on a colorectal cancer cell line, HT-29. Synthesized compounds were designed by docking based virtual screening (DBVS) of a previous constructed compound library against protein targets, known for their important role in colorectal cancer signaling: MEK1, ERK2, PDK1, VEGFR2. Among all synthesized structures, TZ55.7, which was retained as a possible PDK1 (phospholipid-dependent kinase 1) inhibitor, exhibited the most significant cytotoxic activity against HT-29 tumor cell line. The same compound alongside other two, TZ53.7 and TZ3a.7, led to a significant cell cycle arrest in both sub G0/G1 and G0/G1 phase. This study provides future perspectives for the development of new agents containing the 1,2,4-mercapto triazole scaffold with antiproliferative activities in colorectal cancer

Chemical Composition, In Vitro and In Silico Antioxidant Potential of Melissa officinalis subsp. officinalis Essential Oil

The investigation aimed to study the in vitro and in silico antioxidant properties of Melissa officinalis subsp. officinalis essential oil (MOEO). The chemical composition of MOEO was determined using GC–MS analysis. Among 36 compounds identified in MOEO, the main were beta-cubebene (27.66%), beta-caryophyllene (27.41%), alpha-cadinene (4.72%), caryophyllene oxide (4.09%), and alpha-cadinol (4.07%), respectively. In vitro antioxidant properties of MOEO have been studied in 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging, and inhibition of β-carotene bleaching assays. The half-maximal inhibitory concentration (IC50) for the radical scavenging abilities of ABTS and DPPH were 1.225 ± 0.011 μg/mL and 14.015 ± 0.027 μg/mL, respectively, demonstrating good antioxidant activity. Moreover, MOEO exhibited a strong inhibitory effect (94.031 ± 0.082%) in the β-carotene bleaching assay by neutralizing hydroperoxides, responsible for the oxidation of highly unsaturated β-carotene. Furthermore, molecular docking showed that the MOEO components could exert an in vitro antioxidant activity through xanthine oxidoreductase inhibition. The most active structures are minor MOEO components (approximately 6%), among which the highest affinity for the target protein belongs to carvacrol

The Optimized Delivery of Triterpenes by Liposomal Nanoformulations: Overcoming the Challenges

The last decade has witnessed a sustained increase in the research development of modern-day chemo-therapeutics, especially for those used for high mortality rate pathologies. However, the therapeutic landscape is continuously changing as a result of the currently existing toxic side effects induced by a substantial range of drug classes. One growing research direction driven to mitigate such inconveniences has converged towards the study of natural molecules for their promising therapeutic potential. Triterpenes are one such class of compounds, intensively investigated for their therapeutic versatility. Although the pharmacological effects reported for several representatives of this class has come as a well-deserved encouragement, the pharmacokinetic profile of these molecules has turned out to be an unwelcomed disappointment. Nevertheless, the light at the end of the tunnel arrived with the development of nanotechnology, more specifically, the use of liposomes as drug delivery systems. Liposomes are easily synthesizable phospholipid-based vesicles, with highly tunable surfaces, that have the ability to transport both hydrophilic and lipophilic structures ensuring superior drug bioavailability at the action site as well as an increased selectivity. This study aims to report the results related to the development of different types of liposomes, used as targeted vectors for the delivery of various triterpenes of high pharmacological interest

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part II)

Triterpenic acids are a widespread class of phytocompounds which have been found to possess valuable therapeutic properties such as anticancer, anti-inflammatory, hepatoprotective, cardioprotective, antidiabetic, neuroprotective, lipolytic, antiviral, and antiparasitic effects. They are a subclass of triterpenes bearing a characteristic lipophilic structure that imprints unfavorable in vivo properties which subsequently limit their applications. The early investigation of the mechanism of action (MOA) of a drug candidate can provide valuable information regarding the possible side effects and drug interactions that may occur after administration. The current paper aimed to summarize the most recent (last 5 years) studies regarding the MOA of betulinic acid, boswellic acid, glycyrrhetinic acid, madecassic acid, moronic acid, and pomolic acid in order to provide scientists with updated and accessible material on the topic that could contribute to the development of future studies; the paper stands as the sequel of our previously published paper regarding the MOA of triterpenic acids with therapeutic value. The recent literature published on the topic has highlighted the role of triterpenic acids in several signaling pathways including PI3/AKT/mTOR, TNF-alpha/NF-kappa B, JNK-p38, HIF-α/AMPK, and Grb2/Sos/Ras/MAPK, which trigger their various biological activities

The C30-Modulation of Betulinic Acid Using 1,2,4-Triazole: A Promising Strategy for Increasing Its Antimelanoma Cytotoxic Potential

Cancer, in all its types and manifestations, remains one of the most frequent causes of death worldwide; an important number of anticancer drugs have been developed from plants, fungi and animals, starting with natural compounds that were later derivatized in order to achieve an optimized pharmacokinetic/pharmacological profile. Betulinic acid is a pentacyclic triterpenic compound that was identified as an anticancer agent whose main advantage consists in its selective activity, which ensures the almost total lack of cytotoxic side effects. Conjugates of betulinic acid with substituted triazoles, scaffolds with significant pharmacological properties, were synthesized and tested as anticancer agents in order to achieve new therapeutic alternatives. The current paper aims to obtain a C30-1,2,4-triazole derivative of betulinic acid simultaneously acetylated at C3 whose biological activity was tested against RPMI melanoma cells. The compound revealed significant cytotoxic effects at the tested concentrations (2, 10 and 50 μΜ) by significantly decreasing the cell viability to 88.3%, 54.7% and 24.5%, respectively, as compared to the control. The compound’s testing in normal HaCaT cells showed a lack of toxicity, which indicates its selective dose-dependent anticancer activity. The investigation of its underlying molecular mechanism revealed an apoptotic effect induced at the mitochondrial level, which was validated through high-resolution respirometry studies

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part I)

Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids (asiatic acid, oleanolic acid, and ursolic acid), corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value

The Antimelanoma Biological Assessment of Triterpenic Acid Functionalized Gold Nanoparticles

One of several promising strategies for increasing the bioavailability and therapeutic potential of high-lipophilic biologically active compounds is gold nanoparticle formulation. The current study describes the synthesis and biological antimelanoma evaluation of three triterpen-functionalized gold nanoparticles, obtained using our previously reported antimelanoma benzotriazole-triterpenic acid esters. Functionalized gold nanoparticle (GNP) formation was validated through UV-VIS and FTIR spectroscopy. The conjugate’s cytotoxic effects were investigated using HaCaT healthy keratinocytes and A375 human melanoma cells. On A375 cells, all three conjugates demonstrated dose-dependent cytotoxic activity, but no significant cytotoxic effects were observed on normal HaCaT keratinocytes. GNP-conjugates were found to be more cytotoxic than their parent compounds. After treatment with all three GNP-conjugates, 4,6′-diamidino-2-phenylindole (DAPI) staining revealed morphological changes consistent with apoptosis in A375 melanoma cells. Quantitative real-time polymerase chain reaction (RT-qPCR) analysis revealed that the triterpene-GNP conjugate treated A375 melanoma cells had a fold change increase in Bcl-2-associated X protein (BAX) expression and a fold change decrease in B-cell lymphoma 2 (Bcl-2) expression. In A735 melanoma cells, high-resolution respirometry studies revealed that all three GNP-conjugates act as selective inhibitors of mitochondrial function. Furthermore, by examining the effect on each mitochondrial respiratory rate, the results indicate that all three conjugates are capable of increasing the production of reactive oxygen species (ROS), an apoptosis trigger in cancer cells

The Anti-Melanoma Effect of Betulinic Acid Functionalized Gold Nanoparticles: A Mechanistic In Vitro Approach

Implementing metallic nanoparticles as research instruments for the transport of therapeutically active compounds remains a fundamentally vital work direction that can still potentially generate novelties in the field of drug formulation development. Gold nanoparticles (GNP) are easily tunable carriers for active phytocompounds like pentacyclic triterpenes. These formulations can boost the bioavailability of a lipophilic structure and, in some instances, can also enhance its therapeutic efficacy. In our work, we proposed a biological in vitro assessment of betulinic acid (BA)-functionalized GNP. BA-GNP were obtained by grafting BA onto previously synthesized citrate-capped GNP through the use of cysteamine as a linker. The nanoformulation was tested in HaCaT human keratinocytes and RPMI-7951 human melanoma cells, revealing selective cytotoxic properties and stronger antiproliferative effects compared to free BA. Further examinations revealed a pro-apoptotic effect, as evidenced by morphological changes in melanoma cells and supported by western blot data showing the downregulation of anti-apoptotic Bcl-2 expression coupled with the upregulation of pro-apoptotic Bax. GNP also significantly inhibited mitochondrial respiration, confirming its mitochondrial-targeted activity

Novel Semisynthetic Betulinic Acid−Triazole Hybrids with In Vitro Antiproliferative Potential

Betulinic acid, BA, is a lupane derivative that has caught the interest of researchers due to the wide variety of pharmacological properties it exhibits towards tumor cells. Because of their prospective increased anti−proliferative efficacy and improved pharmacological profile, BA derivatives continue to be described in the scientific literature. The current work was conducted in order to determine the antiproliferative activity, under an in vitro environment of the newly developed 1,2,4−triazole derivatives of BA. The compounds and their reaction intermediates were tested on three cancer cell lines, namely RPMI−7951 human malignant melanoma, HT−29 colorectal adenocarcinoma, A549 lung carcinoma, and healthy cell line (HaCaT human keratinocytes). BA−triazole derivatives 4a and 4b revealed lower IC50 values in almost all cases when compared to their precursors, exhibiting the highest cytotoxicity against the RPMI−7951 cell line (IC50: 18.8 μM for 4a and 20.7 μM for 4b). Further biological assessment of these compounds executed on the most affected cell line revealed a mitochondrial level induced apoptotic mechanism where both compounds inhibited mitochondrial respiration in RPMI−7951 cells. Furthermore, the triazole−BA derivatives caused a significant decrease of the anti−apoptotic Bcl−2 gene expression, while increasing the pro−apoptotic BAX gene’s expression

Cytotoxic Potential of Betulinic Acid Fatty Esters and Their Liposomal Formulations: Targeting Breast, Colon, and Lung Cancer Cell Lines

Betulinic acid is a lupane-type pentacyclic triterpene mostly found in birch bark and thoroughly explored for its wide range of pharmacological activities. Despite its impressive biological potential, its low bioavailability has challenged many researchers to develop different formulations for achieving better in vitro and in vivo effects. We previously reported the synthesis of fatty acid esters of betulinic acid using butyric, stearic, and palmitic acids (But-BA, St-BA, and Pal-BA) and included them in surfaced-modified liposomes (But-BA-Lip, St-BA-Lip, Pal-BA-Lip). In the current study, we evaluated the cytotoxic effects of both fatty acid esters and their respective liposomal formulations against MCF-7, HT-29, and NCI-H460 cell line. The cytotoxic assessment of BA derivatives revealed that both the fatty esters and their liposomal formulations acted as cytotoxic agents in a dose- and time-dependent manner. But-BA-Lip exerted stronger cytotoxic effects than the parent compound, BA and its liposomal formulation, and even stronger effects than 5-FU against HT-29 cells (IC50 of 30.57 μM) and NCI-H460 cells (IC50 of 30.74 μM). BA’s fatty esters and their respective liposomal formulations facilitated apoptosis in cancer cells by inducing nuclear morphological changes and increasing caspase-3/-7 activity. The HET-CAM assay proved that none of the tested compounds induced any irritative effect, suggesting that they can be used safely for local applications