Search Results (24)

This review summarizes current knowledge on naturally occurring pristimerin-pristimerin triterpenoid dimers, a rare and structurally diverse class of secondary metabolites reported mainly from Celastraceae species. Known dimers are compiled with emphasis on botanical sources and key architectural features, including the variety of interunit linkages, regio- and stereochemical diversity, and distinct isomeric forms (including atropisomerism). Major advances in structure elucidation and structural revisions are discussed, highlighting the role of modern spectroscopic tools—particularly 2D NMR methods and chiroptical techniques—in resolving connectivity and absolute configuration, and in correcting several earlier assignments. Proposed biosynthetic scenarios are outlined, focusing on the reactivity of the quinone-methide motif and its interconversion with 2,3-diketone forms, as well as (hetero) Diels-Alder-type processes; selected biomimetic studies are summarized as supportive evidence for these pathways. A critical overview of available biological data indicates that many pristimerin dimers display limited activity in common antimicrobial and cytotoxicity assays when compared with monomeric congeners, which may point to alternative ecological roles or storage/transport functions in planta. Finally, key knowledge gaps and future directions are identified, including improved isolation coverage, rigorous synthetic/biomimetic work, and broader pharmacological screening beyond standard panels. Full article

Natural products from plants have played an important role in cancer and neurodegenerative diseases. In this context, the root bark of Maytenus chiapensis (Celastraceae) was investigated to examine its chemical constituents and potential biological activities. Chromatographic separation of the root bark extract yielded a new Diels–Alder adduct (morenine) formed by a triterpenophenolic moiety derived from tingenone and a bicyclic guaiane-type sesquiterpene linked through a 1,4-dioxane bridge. In addition, eight previously reported Diels–Alder adducts—retusonine and cheiloclines A–D and F–H—were isolated, together with their biosynthetic precursors, the quinone-methide triterpenoids (QMTs) pristimerin and tingenone. Structural elucidation was achieved through detailed 1D and 2D NMR spectroscopic analyses. The adducts were tested for cytotoxicity against six cancer cell lines (A549, SW1573, MIA PaCa-2, T-47D, HeLa, and WiDr cell lines), showing moderate-to-low activity compared with their precursors. Continuous live cell imaging identified apoptosis and vacuole formation as the main modes of action of pristimerin in SW1573 cells. Moreover, acetylcholinesterase inhibition assays revealed that cheiloclines B–D, F, and H exhibited up to 50% inhibition. These findings reinforce the potential of Celastraceae species as a source of unique and complex compounds and enhance our understanding of their therapeutic potential. Full article

Chemotherapy-induced neuropathic pain (CINP) can be caused by several chemotherapeutic drugs, including paclitaxel, oxaliplatin, and vincristine, which is difficult to treat with several drugs, including antidepressants and anticonvulsants. The patho-mechanisms of CINP are not completely understood. However, they showed oxidative stress, mitochondrial damage, ion channel damage, and immunological dysfunction. Acting as a key regulator of antioxidant responses, nuclear factor erythroid 2-related factor 2 (Nrf2) decreased oxidative stress and mitochondrial damage. In addition, it plays a role in inhibiting nuclear factor kappa B (NF-κB). A systematic, English-only search of MEDLINE (PubMed) was performed for studies on Nrf2, chemotherapy, and neuropathic pain from database inception through 1 December 2024. Several Nrf2 activators, including tempol, oltipraz, rosiglitazone, pristimerin, cannabidiol, daidzein, bardoxolone methyl, curcumin, resveratrol, and mitoquinone, demonstrated analgesic effects in CINP animal models. Furthermore, in clinical studies, curcumin demonstrated significant efficacy in reducing vincristine-induced neuropathy in pediatric leukemia patients, while the combined administration of alpha-lipoic acid with ipidacrin hydrochloride prevented paclitaxel-induced motor neuropathy and improved axonal function in breast cancer patients. Thus, the purposes of our review article were to summarize the analgesic effects of Nrf2 activators and the patho-mechanisms of Nrf2 in CINP animal, and then the consequences for clinical trials were presented. Full article

Development of paclitaxel-induced neuropathic pain (PINP) during chemotherapy may lead to paclitaxel discontinuation, potentially compromising effective anticancer therapy. PINP can manifest as allodynia. One recently discovered key factor in paclitaxel-induced mechanical allodynia (PIMA) pathogenesis is the elevated activity of monoacylglycerol lipase (MAGL), an enzyme that metabolizes the endocannabinoid 2-arachidonoylglycerol (2-AG). Thus, inhibiting MAGL serves as a potential analgesic target. Notoginsenoside R1 (NGR1), a metabolite of Panax notoginseng, has shown promise in reducing oxidative stress and neuronal apoptosis in nerve injury models. However, its effects on PIMA and MAGL activity have not yet been explored. This study is a proof-of-concept preclinical study investigating the antiallodynic effects of NGR1 on PIMA in female BALB/c mice and also examining its effect on MAGL activity. The effect of treatment of mice with NGR1 intraperitoneally on the development of PIMA was evaluated. Molecular docking using CB-Dock2 compared the binding energies to MAGL of NGR1 and pristimerin, a triterpene MAGL inhibitor. The effects of NGR1 on human recombinant MAGL activity, as well as the MAGL activity in mice paw skin tissues, were assessed using MAGL inhibitor screening and MAGL activity assay kits, respectively. NGR1 prevented the development of PIMA in a dose-dependent manner. The docking scores showed that NGR1 has a good affinity for MAGL (−7.8 kcal/mol, binding energy) but less affinity than pristimerin (−10.3 kcal/mol). NGR1 inhibited the human recombinant MAGL activity in a reversible and concentration-dependent manner, although the inhibition was in a reverse order. Treatment of mice with NGR1 showed a non-significant trend in reducing the paclitaxel-induced increase in MAGL activity in the paw skin. This study shows for the first time that NGR1 prevents the development of PIMA and suggests that NGR1 has affinity for and inhibits human recombinant MAGL activity with a paradoxical inhibition pattern. More mechanistic studies are needed to fully elucidate the molecular mechanisms of NGR1 in preventing PIMA. Full article

Monoacylglycerol lipase (MAGL) degrades the endocannabinoid 2-arachidonyl glycerol. MAGL inhibitors, such as the triterpene pristimerin, alleviate neuropathic pain in animal models. In silico studies were carried out using SwissDock, PyRx-0.8 and CB-Dock2, to check if they correlated with the in vitro MAGL inhibition potency of various triterpenes. In terms of affinity, free energy of binding and docking scores to MAGL, pristimerin (52.75, −9.32, −10.83, and −11.5 kcal/mol) was better than euphol (44.86, −8.49, −9.56, and −10.7 kcal/mol), which in turn was better than β-amyrin (35.17, −7.37, −8.21, and −8.8 kcal/mol). Finally, β-amyrin was better than or equal to α-amyrin (35.10, −7.19, −7.95, and −8.6 kcal/mol). In molecular dynamic simulations (MDSs), pristimerin exhibited the highest stability and reached the steady state after 20 ns with the lowest root mean square fluctuation (RMSF) at the binding site, compared to the triterpenes. The reported half maximal inhibitory concentration (IC₅₀) values of recombinant human and rat MAGL inhibition were in the following order: α-amyrin > β-amyrin > euphol > pristimerin. Linear regression analysis showed that the affinity, free energy of binding, and docking scores significantly correlated with the IC₅₀ of MAGL inhibition. Amongst the triterpenes studied, pristimerin was the most potent inhibitor of MAGL and also had the highest affinity in the in silico studies. Thus, molecular docking and MDS results correlated with the potency of triterpenes inhibiting MAGL activity in vitro and could be used for screening of triterpenes prior to experimental validation. Full article

Background: Acetaminophen (APAP) is a popular and safe pain reliever. Due to its widespread availability, it is commonly implicated in intentional or unintentional overdoses, which result in severe liver impairment. Pristimerin (Prist) is a natural triterpenoid that has potent antioxidant and anti-inflammatory properties. Our goal was to explore the protective effects of Prist against APAP-induced acute liver damage. Method: Mice were divided into six groups: control, Prist control, N-acetylcysteine (NAC) + APAP, APAP, and two Prist + APAP groups. Prist (0.4 and 0.8 mg/kg) was given for five days and APAP on day 5. Liver and blood samples were taken 24 h after APAP administration and submitted for different biochemical and molecular assessments. Results: Prist counteracted APAP-induced acute liver damage, as it decreased general liver dysfunction biomarkers, and attenuated APAP-induced histopathological lesions. Prist decreased oxidative stress and enforced hepatic antioxidants. Notably, Prist significantly reduced the genetic and protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-II), p-phosphatidylinositol-3-kinase (p-PI3K), p-protein kinase B (p-AKT), and the inflammatory cytokines: nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukins-(IL-6 and IL-1β) in hepatic tissues. Additionally, the m-RNA and protein levels of the apoptotic Bcl2-associated X protein (BAX) and caspase-3 were lowered and the anti-apoptotic B-cell leukemia/lymphoma 2 (BCL-2) was increased upon Prist administration. Conclusion: Prist ameliorated APAP-induced liver injury in mice via its potent anti-inflammatory/antioxidative and anti-apoptotic activities. These effects were mediated through modulation of NF-κB/iNOS/COX-II/cytokines, PI3K/AKT, and BAX/BCL-2/caspase-3 signaling pathways. Full article

A fluorescent cell-based assay was developed for the screening of chemicals repressing the expression of human telomerase reverse transcriptase (hTERT). hTERT is reactivated during carcinogenesis and is overexpressed in more than 90% of cancers but is almost silent in normal tissue cells. Because of its critical role in cancer, hTERT is a target in various therapeutic strategies for cancer treatment. In this study, the hTERT promoter was cloned in MCF7 breast cancer cells and used to control the expression of enhanced green fluorescent protein (EGFP). The fluorescence of EGFP indicated the activity of the hTERT promoter, and, in the presence of an hTERT repressor, the EGFP fluorescence signal was reduced as compared to the EGFP fluorescence controlled by the human cytomegalovirus (CMV) promoter, which was not affected by changes in culture conditions and worked as a control. The EGFP reporter cells were cultivated in three-dimensional (3D) microbioreactors to resemble the in vivo tumor physiology and provide in vivo-like responses. The assay’s predictability was demonstrated with three known hTERT inhibitors, pristimerin, epigallocatechin gallate, and n-butylidenephthalide, and further evaluated with five widely used anticancer compounds, doxorubicin, cisplatin, paclitaxel, blasticidin, and tamoxifen. The results showed overall accuracy of over 83.3%, demonstrating the feasibility of using the hTERT promoter with EGFP as a reporter for the screening of potential cancer drugs targeting hTERT. Full article

Maytenus senegalensis (Lam.) Excell, also known as Gymnosporia senegalensis (Lam.) Loes, is distributed particularly in savannah regions of tropical Africa. It is used to treat malaria, tuberculosis, rheumatism and diarrhea, amongst other afflictions. The objective of this comprehensive review is to summarize studies on phytochemistry, molecular docking, pharmacology, toxicology, ethnopharmacology, botany, and clinical trials of M. senegalensis. Data on M. senegalensis were collected using different databases such as Google Scholar, Science Direct, Web of Science, Scopus, SciFinder, Wiley Online, etc. This review showed that 118 biomolecules from different parts of M. senegalensis were identified. A total of 46 compounds were tested for antiplasmodial, anti-inflammatory, and antiproliferative activities, and some in vivo studies were carried out on mice. Isomintlactone (31), pristimerin (24), and jacareubin (32) were analyzed for molecular docking. The crude extracts and fractions had pharmacological activities, including antiparasitic, antimycobacterial, anti-inflammatory, antiviral, antiproliferative, and antidiabetic, while showing low toxicity in mice. Clinical trial studies on the safety and tolerability of M. senegalensis ethanol root bark extracts in male volunteers showed its potential immunomodulatory effects. Another trial specifically evaluated the electrocardiographic effects of M. senegalensis in adult volunteers and showed its advantageous cardiac profile by improving the overall safety profile. Full article

Esophageal cancer (EC) is a very common form of cancer in developing countries, and its exponential progression is a cause for concern. Available treatments face the phenomenon of multi-drug resistance, as well as multiple disabling side effects. The number of deaths is expected to double by 2030 if nothing is done. Due to their high representativeness in plants, phenolic compounds are a potential alternative for halting the spread of this disease, which bereaves many thousands of families every year. This study aims to identify phenolic compounds with activity against esophageal cancer, assess their toxicological profiles, and explore future perspectives. To achieve this, the literature search was meticulously carried out in the Google Scholar, Scopus, Web of Sciences, and Pub-Med/Medline databases, in accordance with the PRISMA 2020 guidelines. The results show that proanthocyanidin and curcumin represent promising therapeutic options, given their significant in vitro and in vivo activity, and their safety in human subjects in clinical trials. Moscatilin, Genistein, and pristimerin have anticancer activities (≤10 µM) very close to those of doxorubicin and 5-FU, although their safety has not yet been fully established. The compounds identified in vivo exhibit highly significant activities compared with the results obtained in vitro, and are sometimes more effective than the molecules conventionally used to treat EC. Generally, with the exceptions of plumbagin, lapachol, and β-lapachone, all other molecules are relatively non-toxic to normal human cells and represent a therapeutic avenue to be explored by pharmaceutical companies in the fight against esophageal cancer. However, more detailed toxicological studies of certain molecules remain a priority. Full article

In our previous study, two oleanane-type pentacyclic triterpenoids (oleanolic acid and maslinic acid) were reported to affect the N-glycosylation and intracellular trafficking of intercellular adhesion molecule-1 (ICAM-1). The present study was aimed at investigating the structure–activity relationship of 13 oleanane-type natural triterpenoids with respect to the nuclear factor κB (NF-κB) signaling pathway and the expression, intracellular trafficking, and N-glycosylation of the ICAM-1 protein in human lung adenocarcinoma A549 cells. Hederagenin, echinocystic acid, erythrodiol, and maslinic acid, which all possess two hydroxyl groups, decreased the viability of A549 cells. Celastrol and pristimerin, both of which possess an α,β-unsaturated carbonyl group, decreased cell viability but more strongly inhibited the interleukin-1α-induced NF-κB signaling pathway. Oleanolic acid, moronic acid, and glycyrrhetinic acid interfered with N-glycosylation without affecting the cell surface expression of the ICAM-1 protein. In contrast, α-boswellic acid and maslinic acid interfered with the N-glycosylation of the ICAM-1 protein, which resulted in the accumulation of high-mannose-type N-glycans. Among the oleanane-type triterpenoids tested, α-boswellic acid and maslinic acid uniquely interfered with the intracellular trafficking and N-glycosylation of glycoproteins. Full article

The growing global burden of malignant tumors with increasing incidence and mortality rates underscores the urgent need for more effective and less toxic therapeutic options. Herbal compounds are being increasingly studied for their potential to meet these needs due to their reduced side effects and significant efficacy. Pristimerin (PS), a triterpenoid from the quinone formamide class derived from the Celastraceae and Hippocrateaceae families, has emerged as a potent anticancer agent. It exhibits broad-spectrum anti-tumor activity across various cancers such as breast, pancreatic, prostate, glioblastoma, colorectal, cervical, and lung cancers. PS modulates several key cellular processes, including apoptosis, autophagy, cell migration and invasion, angiogenesis, and resistance to chemotherapy, targeting crucial signaling pathways such as those involving NF-κB, p53, and STAT3, among others. The main objective of this review is to provide a comprehensive synthesis of the current literature on PS, emphasizing its mechanisms of action and molecular targets with the utmost clarity. It discusses the comparative advantages of PS over current cancer therapies and explores the implications for future research and clinical applications. By delineating the specific pathways and targets affected by PS, this review seeks to offer valuable insights and directions for future research in this field. The information gathered in this review could pave the way for the successful development of PS into a clinically applicable anticancer therapy. Full article

The relationship between oxidative stress and inflammation is well known, and exogenous antioxidants, primarily phytochemical natural products, may assist the body’s endogenous defense systems in preventing diseases due to excessive inflammation. In this study, we evaluated the antioxidant properties of ethnomedicines from Peru that exhibit anti-inflammatory activity by measuring the superoxide scavenging activity of ethanol extracts of Maytenus octogona aerial parts using hydrodynamic voltammetry at a rotating ring-disk electrode (RRDE). The chemical compositions of these extracts are known and the interactions of three methide-quinone compounds found in Maytenus octogona with caspase-1 were analyzed using computational docking studies. Caspase-1 is a critical enzyme triggered during the activation of the inflammasome and its actions are associated with excessive release of cytokines. The most important amino acid involved in active site caspase-1 inhibition is Arg341 and, through docking calculations, we see that this amino acid is stabilized by interactions with the three potential methide-quinone Maytenus octogona inhibitors, hydroxytingenone, tingenone, and pristimerin. These findings were also confirmed after more rigorous molecular dynamics calculations. It is worth noting that, in these three compounds, the methide-quinone carbonyl oxygen is the preferred hydrogen bond acceptor site, although tingenone’s other carbonyl group also shows a similar binding energy preference. The results of these calculations and cyclovoltammetry studies support the effectiveness and use of anti-inflammatory ethnopharmacological ethanol extract of Maytenus octogona (L’Héritier) DC. Full article

This review identifies terpenes isolated from the medicinal Angiosperms of Asia and the Pacific with antibacterial and/or antifungal activities and analyses their distribution, molecular mass, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and library searches from 1968 to 2022. About 300 antibacterial and/or antifungal terpenes were identified during this period. Terpenes with a MIC ≤ 2 µg/mL are mostly amphiphilic and active against Gram-positive bacteria, with a molecular mass ranging from about 150 to 550 g/mol, and a polar surface area around 20 Ų. Carvacrol, celastrol, cuminol, dysoxyhainic acid I, ent-1β,14β-diacetoxy-7α-hydroxykaur-16-en-15-one, ergosterol-5,8-endoperoxide, geranylgeraniol, gossypol, 16α-hydroxy-cleroda-3,13 (14)Z-diene-15,16-olide, 7-hydroxycadalene, 17-hydroxyjolkinolide B, (20R)-3β-hydroxy-24,25,26,27-tetranor-5α cycloartan-23,21-olide, mansonone F, (+)-6,6′-methoxygossypol, polygodial, pristimerin, terpinen-4-ol, and α-terpineol are chemical frameworks that could be candidates for the further development of lead antibacterial or antifungal drugs. Full article

Rheumatoid arthritis (RA) is characterized by systemic inflammation and synovial hyperplasia. Pristimerin, a natural triterpenoid isolated from plants belonging to the Celastraceae and Hippocrateaceae families, has been reported to exhibit anti-inflammation and anti-proliferation activities. Our study aims to reveal the antiarthritic effects of pristimerin and explore its potential mechanism using in vitro, in silico, and in vivo methods. In the present study, pristimerin treatment led to a dose-dependent decrease in cell viability and migration in TNF-α stimulated human rheumatoid arthritis fibroblast-like synoviocytes MH7A. Moreover, UPLC-LTQ-Orbitrap-based cell metabolomics analysis demonstrated that phospholipid biosynthesis, fatty acid biosynthesis, glutathione metabolism and amino acid metabolic pathways were involved in TNF-α induced MH7A cells after pristimerin treatment. In addition, the adjuvant–induced arthritis (AIA) rat model was employed, and the results exhibited that pristimerin could effectively relieve arthritis symptoms and histopathological damage as well as reduce serum levels of TNF-α, NO and synovial expressions of p-Akt and p-Erk in AIA rats. Furthermore, network pharmacology analysis was performed to visualize crucial protein targets of pristimerin for RA treatment, which showed that the effects were mediated through the MAPK/Erk1/2, PI3K/Akt pathways and directing binding with TNF-α. Taken together, our study not only offered new insights into the biochemical mechanism of natural compounds for RA treatment, but also provided a strategy that integrated in vitro, in silico and in vivo studies to facilitate screening of new anti-RA drugs. Full article

A literature search on plant natural products with antimyeloma activity until the end of 2020 resulted in 92 compounds with effects on at least one human myeloma cell line. Compounds were divided in different compound classes and both their structure–activity-relationships as well as eventual correlations with the pathways described for Multiple Myeloma were discussed. Each of the major compound classes in this review (alkaloids, phenolics, terpenes) revealed interesting candidates, such as dioncophyllines, a group of naphtylisoquinoline alkaloids, which showed pronounced and selective induction of apoptosis when substituted in position 7 of the isoquinoline moiety. Interestingly, out of the phenolic compound class, two of the most noteworthy constituents belong to the relatively small subclass of xanthones, rendering this group a good starting point for possible further drug development. The class of terpenoids also provides noteworthy constituents, such as the highly oxygenated diterpenoid oridonin, which exhibited antiproliferative effects equal to those of bortezomib on RPMI8226 cells. Moreover, triterpenoids containing a lactone ring and/or quinone-like substructures, e.g., bruceantin, whitaferin A, withanolide F, celastrol, and pristimerin, displayed remarkable activity, with the latter two compounds acting as inhibitors of both NF-κB and proteasome chymotrypsin-like activity. Full article