Design and synthesis of spiro derivatives of parthenin as novel anti-cancer agents

Functionalized Cyclopentenones with Low Electrophilic Character as Anticancer Agents

In this study were synthesized non-Michael acceptor cyclopentenones (CP) from biomass derivative furfural as anticancer agents. Cyclic enones, both from natural sources and synthetic analogues, have been described as cytotoxic agents. Most of these agents were unsuccessful in becoming valuable therapeutic agents due to toxicity problems derived from unselective critical biomacromolecule alkylation. This may be caused by Michael addition to the enone system. Ab initio studies revealed that 2,4-substituted CPs are less prone to Michael additions, and as such were tested three families of those derivatives. We prepare the new CPs from furfural through a tandem furan ring opening/Nazarov electrocyclization and further functionalization. Experimentally the 2,4-substituted CPs exhibited no reactivity towards sulphur nucleophiles, while maintaining cytotoxicity against HT-29, MCF-7, NCI-H460, HCT-116 and MDA-MB 231 cells lines. Moreover, the selected CP are non-toxic against healthy HEK 293T cell lines and present proper calculated drug-like properties.

Investigation of radiation protective features of azadispiro derivatives and their genotoxic potential with Ames/Salmonella test system

PURPOSE

Five different types of synthesized azadispiro derivatives have been analyzed for radiation absorption capacity and determined their potential to be exploited as substances for a drug to be developed against radiation has been investigated.

MATERIAL AND METHODS

Fast neutron attenuation parameters like the effective mean free path, half-value layer (HVL), removal cross-sections, and neutron transmission number were found with the Monte Carlo simulation Geometry And Tracking (GEANT4) code. Gamma radiation absorption parameters, such as effective atom number (Z_eff), mean free path (MFP), mass attenuation coefficient (MAC), and half-value layer (HVL) were theoretically determined with WinXCom software. Besides, the exposure build-up factor (EBF) was calculated by using GP fitting parameters. Neutron absorption dose rate was experimentally calculated with ²⁴¹Am-Be fast neutron source which has 4.5 MeV of energy, 74 GBq activity, and portative BF₃ neutron detector. Ames/Salmonella test systems were used for the genotoxic potentials of the azadispiro derivatives.

RESULTS AND CONCLUSIONS

Experimental and theoretical results were checked with paraffin and High-Density Polyethylene. The results showed that Azadispiro derivatives have neutron radiation absorption capability close to paraffin and High-Density Polyethylene. The gamma radiation absorption properties for azadispiro derivatives have been investigated, and it has been observed that these materials can absorb gamma radiation. Ames/Salmonella assay was used to examine whether the derivatives had a genotoxic effect probability or not. The results showed that these derivatives were genotoxic and safe at test doses (up to 5 mM). Consequently, it has been understood that these azadispiro derivatives can be used as active and genotoxic safety ingredients in the production of a protective drug against both neutrons and gamma rays.

Parthenium hysterophorus's Endophytes: The Second Layer of Defense against Biotic and Abiotic Stresses

Parthenium hysterophorus L. is considered an obnoxious weed due to its rapid dispersal, fast multiplications, and agricultural and health hazards. In addition to its physio-molecular and phytotoxic allelochemical usage, this weed most probably uses endophytic flora as an additional line of defense to deal with stressful conditions and tolerate both biotic and abiotic stresses. The aim of this article is to report the diversity of endophytic flora (fungi and bacteria) in P. hysterophorus and their role in the stress mitigation (biotic and abiotic) of other important crops. Various endophytes were reported from P. hysterophorus and their roles in crops evaluated under biotic and abiotic stressed conditions. These endophytes have the potential to alleviate different stresses by improving crops/plants growth, development, biomass, and photosynthetic and other physiological traits. The beneficial role of the endophytes may be attributed to stress-modulating enzymes such as the antioxidants SOD, POD and APX and ACC deaminases. Additionally, the higher production of different classes of bioactive secondary metabolites, i.e., flavonoids, proline, and glutathione may also overcome tissue damage to plants under stressed conditions. Interestingly, a number of medicinally important phytochemicals such as anhydropseudo-phlegmcin-9, 10-quinone-3-amino-8-O methyl ether 'anhydropseudophlegmacin-9, 10-quinone-3-amino-8-Omethyl ether were reported from the endophytic flora of P. hysterophorus. Moreover, various reports revealed that fungal and bacterial endophytes of P. hysterophorus enhance plant growth-promoting attributes and could be added to the consortium of biofertilizers.

Expedient metal-free preparation of aryl aziridines via thermal cycloaddition reactions

A straightforward synthesis of aryl aziridines is reported from readily available azides and alkenes and using technical solvents in the presence of air. This methodology does not require any additives and the obtained compounds can be employed in ring-opening and ring-expansion reactions.

Synthesis of novel chiral spiro-β-lactams from nitrile oxides and 6-(Z)-(benzoylmethylene)penicillanate: batch, microwave-induced and continuous flow methodologies

The first examples of the diastereoselective 1,3-dipolar cycloaddition reaction of nitrile oxides and 6-alkylidene penicillanates leading to chiral spiroisoxazoline-penicillanates are reported. The synthesis of this new type of penicillanate involved the selective generation of two consecutive stereogenic centers, including a quaternary chiral center. Furthermore, the present work also describes the outcomes of these 1,3-dipolar cycloaddition reactions under three distinct reaction conditions (conventional heating, microwave irradiation and continuous flow). The successful use of the continuous flow technique as well as the proper selection of the reaction media allowed the development of a sustainable route to chiral spiroisoxazoline-penicillanates.

The first examples of the diastereoselective 1,3-dipolar cycloaddition reaction of nitrile oxides and 6-alkylidene penicillanates leading to chiral spiroisoxazoline-penicillanates are reported.

Comprehensive review on ethnobotanical uses, phytochemistry, biological potential and toxicology of Parthenium hysterophorus L.: A journey from noxious weed to a therapeutic medicinal plant

ETHNO-PHARMACOLOGICAL RELEVANCE

Parthenium hysterophorus L. is a noxious weed and a species of flowering plant in the Asteraceae family. It is regarded as the seventh most deadly weed in the world: harmful to both humans and livestock. It is widely known as Congress Grass or Feverfew. Despite its pitfalls, P. hysterophorus bestows medicinal effects. Although prolific in nature and difficult to control, many novel applications of this controversial herb have been discovered as an approach to manage the weed.

AIM

The current review aims to compile all the ethnobotanical, phytochemistry, biological activities and utilities, clinical studies and toxicity data available on P. hysterophorus and its major chemical constituent parthenin.

MATERIALS AND METHODS

Extensive literature surveyed Google search, Google scholar, Wiley online library, Elsevier, Springer, Science direct, American Chemical Society, Royal Society of Chemistry and Research Gate.

RESULT

According to the study, P. hysterophorus is utilized as a traditional medicine throughout Central America and the Caribbean. It can be used to treat skin infections, dermatitis, amoebic dysentery, and as an analgesic in the treatment of muscular rheumatism. The extracts obtained from P. hysterophorus have anti-inflammatory, antioxidant, larvicidal, anti-microbial, insecticidal, hypoglycaemic and anti-cancer activity.

CONCLUSION

The earlier investigations confirmed that P. hysterophorus has numerous traditional and biological applications. However, the scientific data are limited in clinical and toxicological studies. Therefore, further research is required on clinical and toxicological aspects to understand the complete potential and effects of P. hysterophorus.

Parthenin-A Sesquiterpene Lactone with Multifaceted Biological Activities: Insights and Prospects

Parthenin, a sesquiterpene lactone of pseudoguaianolide type, is the representative secondary metabolite of the tropical weed Parthenium hysterophorus (Asteraceae). It accounts for a multitude of biological activities, including toxicity, allergenicity, allelopathy, and pharmacological aspects of the plant. Thus far, parthenin and its derivatives have been tested for chemotherapeutic abilities, medicinal properties, and herbicidal/pesticidal activities. However, due to the lack of toxicity–bioactivity relationship studies, the versatile properties of parthenin are relatively less utilised. The possibility of exploiting parthenin in different scientific fields (e.g., chemistry, medicine, and agriculture) makes it a subject of analytical discussion. The present review highlights the multifaceted uses of parthenin, on-going research, constraints in the practical applicability, and the possible workarounds for its successful utilisation. The main aim of this comprehensive discussion is to bring parthenin to the attention of researchers, pharmacologists, natural product chemists, and chemical biologists and to open the door for its multidimensional applications.

Natural Products Containing Olefinic Bond: Important Substrates for Semi-synthetic Modification Towards Value Addition

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Semi-synthesis, the way of preparing novel bioactive molecules via modification of compounds isolated from natural sources is very much useful nowadays in the drug discovery process. The modification is based on the reaction of functional group(s) present in a natural compound. Among the examples of functional group transformation, double bond modification is also common in the literature. Several reactions like hydrogenation, cyclopropanation, epoxidation, addition reaction (halogenations, hydroxylation), Michael addition, Heck reaction, cycloaddition, dipolar cycloaddition, etc. are employed for this purpose. In this review, we have tried to gather the reactions performed with several double bond containing classes of natural products like diterpenes, xanthones, sesquiterpene exomethylene lactones, diaryl heptanoids, steroidal lactones, triterpenoids, limonoids, and alkamides. Where available, the effects of transformations on the biological activities of the molecules are also mentioned.

Applications of Sesquiterpene Lactones: A Review of Some Potential Success Cases

Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.

A Molecular Electron Density Theory Study of the Chemoselectivity, Regioselectivity, and Diastereofacial Selectivity in the Synthesis of an Anticancer Spiroisoxazoline derived from α-Santonin

The [3 + 2] cycloaddition (32CA) reaction of an α-santonin derivative, which has an exocyclic C–C double bond, with p-bromophenyl nitrile oxide yielding only one spiroisoxazoline, has been studied within the molecular electron density theory (MEDT) at the MPWB1K/6-311G(d,p) computational level. Analysis of the conceptual density functional theory (CDFT) reactivity indices and the global electron density transfer (GEDT) account for the non-polar character of this zwitterionic-type 32CA reaction, which presents an activation enthalpy of 13.3 kcal·mol⁻¹. This 32CA reaction takes place with total ortho regioselectivity and syn diastereofacial selectivity involving the exocyclic C–C double bond, which is in complete agreement with the experimental outcomes. While the C–C bond formation involving the β-conjugated carbon of α-santonin derivative is more favorable than the C–O one, which is responsible for the ortho regioselectivity, the favorable electronic interactions taking place between the oxygen of the nitrile oxide and two axial hydrogen atoms of the α-santonin derivative are responsible for the syn diastereofacial selectivity.

What Has Come out from Phytomedicines and Herbal Edibles for the Treatment of Cancer?

Several modern treatment strategies have been adopted to combat cancer with the aim of minimizing toxicity. Medicinal plant-based compounds with the potential to treat cancer have been widely studied in preclinical research and have elicited many innovations in cutting-edge clinical research. In parallel, researchers have eagerly tried to decrease the toxicity of current chemotherapeutic agents either by combining them with herbals or in using herbals alone. The aim of this article is to present an update of medicinal plants and their bioactive compounds, or mere changes in the bioactive compounds, along with herbal edibles, which display efficacy against diverse cancer cells and in anticancer therapy. It describes the basic mechanism(s) of action of phytochemicals used either alone or in combination therapy with other phytochemicals or herbal edibles. This review also highlights the remarkable synergistic effects that arise between certain herbals and chemotherapeutic agents used in oncology. The anticancer phytochemicals used in clinical research are also described; furthermore, we discuss our own experience related to semisynthetic derivatives, which are developed based on phytochemicals. Overall, this compilation is intended to facilitate research and development projects on phytopharmaceuticals for successful anticancer drug discovery.

Development of Anticancer Agents from Plant-Derived Sesquiterpene Lactones

Sesquiterpene lactones are of considerable interest due to their potent bioactivities, including cancer cell cytotoxicity and antineoplastic efficacy in in vivo studies. Among these compounds, artesunate, dimethylaminoparthenolide, and L12ADT peptide prodrug, a derivative of thapsigargin, are being evaluated in the current cancer clinical or preclinical trials. Based on the structures of several antitumor sesquiterpene lactones, a number of analogues showing greater potency have been either isolated as natural products or partially synthesized, and some potential anticancer agents that have emerged from this group of lead compounds have been investigated extensively. The present review focuses on artemisinin, parthenolide, thapsigargin, and their naturally occurring or synthetic analogues showing potential anticancer activity. This provides an overview of the advances in the development of these types of sesquiterpene lactones as potential anticancer agents, including their structural characterization, synthesis and synthetic modification, and antitumor potential, with the mechanism of action and structure-activity relationships also discussed. It is hoped that this will be helpful in stimulating the further interest in developing sesquiterpene lactones and their derivatives as new anticancer agents.

Synthesis of novel spiro-isoxazoline and spiro-isoxazolidine derivatives of tomentosin

A series of novel enantiomerically pure spiro-(isoxazolidines/isoxazolines) were synthesized regioselectively by 1,3-dipolar cycloaddition using nitrones and nitrile oxides, on the exocyclic double bond of tomentosin extracted from Dittrichia viscosa.

Synthesis, molecular structure and spectroscopic investigations of novel fluorinated spiro heterocycles

This paper describes an efficient and regioselective method for the synthesis of novel fluorinated spiro-heterocycles in excellent yield by cascade [5+1] double Michael addition reactions. The compounds 7,11-bis(4-fluorophenyl)-2,4-dimethyl- 2,4-diazaspiro[5.5] undecane-1,3,5,9-tetraone (3a) and 2,4-dimethyl-7,11-bis (4-(trifluoromethyl)phenyl)-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone (3b) were characterized by single-crystal X-ray diffraction, FT-IR and NMR techniques. The optimized geometrical parameters, infrared vibrational frequencies and NMR chemical shifts of the studied compounds have also been calculated using the density functional theory (DFT) method, using Becke-3-Lee-Yang-Parr functional and the 6-311G(d,p) basis set. There is good agreement between the experimentally determined structural parameters, vibrational frequencies and NMR chemical shifts of the studied compounds and those predicted theoretically. The calculated natural atomic charges using NBO method showed higher polarity of 3a compared to 3b.The calculated electronic spectra are also discussed based on the TD-DFT calculations.

Microwave-assisted synthesis and antimicrobial evaluation of novel spiroisoquinoline and spiropyrido[4,3-d]pyrimidine derivatives

Bromination of N-substituted homophthalimides and tetrahydropyrido[4,3-d]-pyrimidine-5,7-diones produces 4,4-dibromohomophthalimide and 8,8-dibromo-tetrahydropyrido[4,3-d]pyrimidine-5,7-dione derivatives, respectively, that can be used as precursors for spiro derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiroisoquinoline and spirotetrahydropyrido[4,3-d]-pyrimidine-5,7-dione derivatives, respectively. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro derivatives. All new compounds are prepared by using the usual chemical conditions and microwave assisted conditions. The latter conditions improved the reaction yields, reduced reaction times and ameliorated the effects on the surrounding environment as the reactions are carried out in closed systems. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, MS, ¹H-NMR and ¹³C-NMR and elemental analyses. Some of the newly synthesized compounds were tested for their antimicrobial activities, whereby four of them showed moderate activities and the rest showed low or no activities towards the investigated species.

Antiproliferative potential of a novel parthenin analog P16 as evident by apoptosis accompanied by down-regulation of PI3K/AKT and ERK pathways in human acute lymphoblastic leukemia MOLT-4 cells

Leukemia is one of the deadliest types of cancer. Lack of effective treatment strategies has resulted in an extensive quest for new therapeutic molecules against it. This study explores the molecular mechanism of anticancer activity of P16, a semisynthetic analog of parthenin, against the human acute lymphoblastic leukemia MOLT-4 cells. P16 displayed antiproliferative activity in different cancer cell lines; however, MOLT-4 cells showed highest sensitivity for P16 with IC50 value of 0.6μM. Further studies revealed that P16 induced cell death by apoptosis. It caused mitochondrial stress, which was mediated by the translocation of Bax from cytosol to mitochondria and release of cytochrome c into the cytosol and consequent activation of caspase-9. However, P16 was also able to activate caspase-8, thus involving both extrinsic and intrinsic pathways of apoptosis. Further, activation of caspase-3 led to cleavage of its target proteins PARP-1 and ICAD, which resulted in apoptotic DNA damage. P16 induced apoptosis was accompanied by the down-regulation of important leukemic cell survival proteins like pAKT (S473), pAKT (T308), pP70S6K, pCRAF, and pERK1/2. However, inhibition of caspases by Z-VAD-FMK reversed the down-regulatory effect of P16 on pAKT (S473) and pP70S6K, as evident by the cell viability assay and flow cytometric analysis but this inhibition did not completely reverse the antiproliferative effect of P16, thereby indicating the role of additional factors apart from caspases in P16 induced apoptosis in MOLT-4 cells. Owing to its antiproliferative potential against leukemia cells, P16 can further be explored as an effective therapeutics against leukemia.

Antioxidant mediated protective effect of Parthenium hysterophorus against oxidative damage using in vitro models

BACKGROUND

Parthenium hysterophorus L. (Asteraceae) is a common weed occurring throughout the globe. In traditional medicine its decoction has been used for treatment of many infectious and degenerative diseases. This work was therefore designed to assess the phytochemical constitution of P. hysterophorus flower and root extracts and to evaluate their reducing power, radical scavenging activity as well as protective efficacy against membrane lipid damage.

METHODS

Dried flower and root samples were sequentially extracted with non-polar and polar solvents using Soxhlet apparatus. The phytochemical screening was done using standard chemical methods and thin layer chromatography. Total phenolic content was determined spectrophotometrically. Reducing power and hydroxyl radical scavenging activity assays were used to measure antioxidant activity. Protection against membrane damage was evaluated by inhibition of lipid peroxidation (TBARS assay) in rat kidney homogenate.

RESULTS

Flavonoids, terpenoids, alkaloids and cardiac glycosides were present in all the extract. The total phenol contents in flower and root extracts were found to be in the range 86.69-320.17 mg propyl gallate equivalent (PGE)/g and 55.47-253.84 mg PGE/g, respectively. Comparatively better reducing power was observed in hexane fractions of flower (0.405) and root (0.282). Benzene extract of flower and ethyl acetate fraction of root accounted for appreciable hydroxyl radical scavenging activity (75-77%). Maximum protection against membrane lipid peroxidative damage among flower and root extracts was provided by ethanol (55.26%) and ethyl acetate (48.95%) fractions, respectively. Total phenolic content showed positive correlations with reducing power and lipid peroxidation inhibition (LPOI) % in floral extracts as well as with hydroxyl radical scavenging activity and LPOI % in root extracts.

CONCLUSION

Study established that phytochemicals present in P. hysterophorus extracts have considerable antioxidant potential as well as lipo-protective activity against membrane damage.

Sesquiterpene lactones as drugs with multiple targets in cancer treatment: focus on parthenolide

Sesquiterpene lactones (SLs) constitute a large and diverse group of biologically active plant compounds that possess anti-inflammatory and antitumor activity. The subclass germacranolides is one of the major groups of SLs. It includes parthenolide, a highly cytotoxic SL that is being tested in clinical trials as an anti-cancer agent. In this review, we focus on SL antitumor activity related to cell-cycle arrest, differentiation, apoptosis induction through the intrinsic pathway, and sensitization of the extrinsic pathway. We also address the regression of tumors in response to cotreatment with conventional chemotherapeutics. We review the nuclear factor-κB-targeted anti-inflammatory activity in vitro and in vivo and relate it to the SL structural features involved in the molecular mechanisms. It is obvious that SLs are emerging as promising anticancer agents, but more investigations are required to fully understand the molecular mechanisms of known SLs in different cell death modalities and how these mechanisms contribute toward the potent antitumor and anti-inflammatory activities of SLs.

Synthesis and anticancer activity of novel spiro-isoxazoline and spiro-isoxazolidine derivatives of α-santonin

In the present study, novel spiro derivatives of α-santonin were prepared and tested for their anticancer activity against a panel of six human cancer cell lines. Spiro-isoxazoline and spiro-isoxazolidine derivatives have been generated on C-ring of α-santonin (α-methylene-γ-butyrolactone) by the 1,3-dipolar cycloaddition of α-santonin derivative 6 with nitrile oxides 7 and nitrones 9 respectively. Among all, compound 10b″ had shown IC50 of 0.01, 0.5 and 0.3 μM against PC-3, THP-1 and MCF-7 cell lines respectively. Further, flow cytometry studies showed that PC-3 cells treated with the spiro-isoxazolidine derivative 10b″ were arrested in the sub G1 phase of the cell cycle in a concentration dependent manner. The spiro-isoxazolidine derivative 10b″ also showed concentration dependent inhibitory activity against NF-κB, p65 with 57% inhibition in 24 h at 10 μM.

Microfluidics assisted synthesis and bioevaluation of sinomenine derivatives as antiinflammatory agents

Sinomenine (1) is currently used for the treatment of rheumatoid arthritis (RA) in China and there is still room for the improvement of its efficacy. In present study, capillary based microfluidic system was effectively applied for the syntheses of two novel series of sinomenine derivatives. The Heck reactions in microreactor gave much higher conversions compared to the batch ones. The two-step synthesis of the isoxazoline in microreactor greatly shortened the reaction time without any isolation of intermediates. The inhibitory activity of synthesized compounds on the TNF-α-induced nuclear factor kappa B (NF-κB) activation was evaluated in vitro. Among the compounds, 3c and 3g showed the potent inhibitory activity. Furthermore, 3g exhibited the antiinflammatory effect in vivo.