Anticancer activity of 7-epiclusianone, a benzophenone from Garcinia brasiliensis, in glioblastoma

A review of natural products and small-molecule therapeutics acting on central nervous system malignancies: Approaches for drug development, targeting pathways, clinical trials, and challenges

In 2021, the World Health Organization released the fifth edition of the central nervous system (CNS) tumor classification. This classification uses histopathology and molecular pathogenesis to group tumors into more biologically and molecularly defined entities. The prognosis of brain cancer, particularly malignant tumors, has remained poor worldwide, approximately 308,102 new cases of brain and other CNS tumors were diagnosed in the year 2020, with an estimated 251,329 deaths. The cost and time-consuming nature of studies to find new anticancer agents makes it necessary to have well-designed studies. In the present study, the pathways that can be targeted for drug development are discussed in detail. Some of the important cellular origins, signaling, and pathways involved in the efficacy of bioactive molecules against CNS tumorigenesis or progression, as well as prognosis and common approaches for treatment of different types of brain tumors, are reviewed. Moreover, different study tools, including cell lines, in vitro, in vivo, and clinical trial challenges, are discussed. In addition, in this article, natural products as one of the most important sources for finding new chemotherapeutics were reviewed and over 700 reported molecules with efficacy against CNS cancer cells are gathered and classified according to their structure. Based on the clinical trials that have been registered, very few of these natural or semi-synthetic derivatives have been studied in humans. The review can help researchers understand the involved mechanisms and design new goal-oriented studies for drug development against CNS malignancies.

Hypericum sampsonii Hance: a review of its botany, traditional uses, phytochemistry, biological activity, and safety

Ethnopharmacological relevance: Hypericum sampsonii Hance, also known as Yuanbao Cao in Chinese, is a traditional medicinal herb from the Guttiferae family and has been widely used in China to treat various conditions, including dysentery, enteritis, mastitis, scrofula, and contusion. Aim of the review: This review aims to provide a comprehensive overview of the botany, traditional uses, phytochemistry, biological activity and safety of H. sampsonii and to highlight its potential for medical application and drug development. Materials and methods: We searched several databases, i.e., Web of Science, SciFinder, PubMed, CBM, CNKI, Google Scholar, etc., for relevant information on H. sampsonii. Additionally, we also consulted some books on Chinese medicine. Results: To date, 227 secondary metabolites have been isolated from H. sampsonii, including polycyclic polyprenylated acylphloroglucinols (PPAPs), benzophenones, xanthones, flavonoids, naphthodianthrones, anthraquinones and aromatic compounds. These metabolites exhibit various biological activities such as anti-inflammatory, anti-tumor, anti-depressant, anti-oxidant, anti-viral and anti-bacterial effects. PPAPs are considered the main active metabolites with rich biological activities. Despite being known as rich source of PPAPs, the full extent of H. sampsonii biological activities, including their potential as PDE4 inhibitors, remained unclear. Since, previous studies have mainly been based on structural identification of metabolites in H. sampsonii, and efficacy evaluations of these metabolites based on clinical applications of H. sampsonii lack sufficient data. However, current evidence suggest that PPAPs are the most likely material basis for efficacy. From the limited information available so far, there is no evidence of potential safety issues and the safety data are limited. Conclusion: Collectively, this review provides a comprehensive overview of the botany, traditional uses, phytochemistry, pharmacology, and safety of H. sampsonii, a valuable medicinal plant in China with various pharmacological activities. Based on pharmacological studies, H. sampsonii shows potential for treating gastrointestinal and gynecological disorders as well as traumatic injuries, which aligns with traditional medicinal use due to the presence of PPAPs, benzophenones, xanthones, and flavonoids. Therefore, further studies are needed to evaluate the pharmacological effects and elucidate the pharmacological mechanisms. In addition, pharmacological mechanisms and safety evaluation of PPAPs on animal models need to be clarified. Yet, further comprehensive studies are required to elucidate the phytochemical constituents, pharmacological mechanisms, structure-activity relationships, safety evaluation, and quality standards of this plant. Takentogether, this review highlights the potential of H. sampsonii for medical application and drug development.

Three New Benzophenone Derivatives from Selaginella tamariscina

Six compounds including three new benzophenones, selagibenzophenones D-F (1-3), two known selaginellins (4-5) and one known flavonoid (6), were isolated from Selaginella tamariscina. The structures of new compounds were established by 1D-, 2D-NMR and HR-ESI-MS spectral analyses. Compound 1 represents the second example of diarylbenzophenone from natural sources. Compound 2 possesses an unusual biphenyl-bisbenzophenone structure. Their cytotoxicity against human hepatocellular carcinoma HepG2 and SMCC-7721 cells and inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells were evaluated. Compound 2 showed moderate inhibitory activity against HepG2 and SMCC-7721 cells, and compounds 4 and 5 showed moderate inhibitory activity to HepG2 cells. Compounds 2 and 5 also exhibited inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production.

Triterpene Derivatives from Garcinia oligantha and Their Anti-Cancer Activity

Phytochemical investigations of leaves and twigs from Garcinia oligantha Merr. resulted in the isolation of five undescribed triterpene derivatives (1-5) and six known analogs (6-11). Their structures were determined based on extensive spectroscopic data and high-resolution mass spectra analyses. Compounds 1-11 were tested for their in vitro cytotoxicity against three human cancer cell lines (HeLa, HepG-2, and MCF-7). Compounds 1, 2, 8, and 11 exhibited broad and significant cytotoxicity against the tested cell lines with IC50 values ranging from 5.04 to 21.55 μM. Compounds 5 and 9 showed cytotoxicity against HeLa and MCF-7 with IC50 values ranging from 13.22 to 19.62 μM. The preliminary structure-activity relationship for the 11 isolated compounds is also discussed.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

Theoretical study of keto-enol tautomerism in 7-epi-clusianone by quantum chemical calculations of NMR chemical shifts

Plants from the Garcinia genus have been used worldwide due to their therapeutic properties. Among the various metabolites isolated from this genus, 7-epi-clusianone, a tetraprenylated benzophenone, stands out for its wide range of identified biological activities. This benzophenone can exist in five tautomeric forms, although the benzene-d₆ and chloroform-d₃ solution nuclear magnetic resonance (NMR) spectra revealed only two tautomeric forms (B and C) in equilibrium, with concentration ratio depending on the solvent in which the spectrum was obtained. Calculated energy values suggested that tautomeric forms B and E would be prevalent in benzene-d₆ solution, in contrast to the experimental data. Considering this conflicting result, we employed the statistical DP4 + method based on ¹³C and ¹H NMR chemical shift calculations, in the gas phase and in benzene-d₆ solution, to confirm that the B and C tautomeric forms of 7-epi-clusianone are the most prevalent in the experimental conditions.

Review On Documented Medicinal Plants Used For The Treatment Of Cancer

Background:

Cancer is a frightful disease and it is the second leading cause of death worldwide. Naturally derived compounds are gaining interest of research workers as they have less toxic side effects as compared to currently used treatments such as chemotherapy. Plants are the pool of chemical compounds which provides a promising future for research on cancer.

Objective:

This review paper provides updated information gathered on medicinal plants and isolated phytoconstituents used as anticancer agents and summarises the plant extracts and their isolated chemical constituents exhibiting anticancer potential on clinical trials.

Methods:

An extensive bibliographic investigation was carried out by analysing worldwide established scientific databases like SCOPUS, PUBMED, SCIELO, ScienceDirect, Springerlink, Web of Science, Wiley, SciFinder and Google Scholar etc. In next few decades, herbal medicine may become a new epoch of medical system.

Results:

Many researches are going on medicinal plants for the treatment of cancer but it is a time to increase further experimental studies on plant extracts and their chemical constituents to find out their mechanism of action at molecular level.

Conclusion:

The article may help many researchers to start off further experimentation that might lead to the drugs for the cancer treatment.

Medicinal Potential of Garcinia Species and Their Compounds

Garcinia is a genus of Clusiaceae, distributed throughout tropical Asia, Africa, New Caledonia, Polynesia, and Brazil. Garcinia plants contain a broad range of biologically active metabolites which, in the last few decades, have received considerable attention due to the chemical compositions of their extracts, with compounds which have been shown to have beneficial effects in several diseases. Our work had the objective of reviewing the benefits of five Garcinia species (G. brasiliensis, G. gardneriana, G. pedunculata, G. cambogia, and G. mangstana). These species provide a rich natural source of bioactive compounds with relevant therapeutic properties and anti-inflammatory effects, such as for the treatment of skin disorders, wounds, pain, and infections, having demonstrated antinociceptive, antioxidant, antitumoral, antifungal, anticancer, antihistaminic, antiulcerogenic, antimicrobial, antiviral, vasodilator, hypolipidemic, hepatoprotective, nephroprotective, and cardioprotective properties. This demonstrates the relevance of the genus as a rich source of compounds with valuable therapeutic properties, with potential use in the prevention and treatment of nontransmissible chronic diseases.

A tetraprenylated benzophenone 7-epiclusianone induces cell cycle arrest at G1/S transition by modulating critical regulators of cell cycle in breast cancer cell lines

Breast cancer is a complex disease and encompassing different types of tumor. Although advances in understanding of the molecular bases of breast cancer biology, the therapeutic proposals available still are not effective. In this scenario, the present study aimed to evaluate the mechanisms associated to antitumor activity of 7-Epiclusianone (7-Epi), a tetraprenylated benzophenone, on luminal A (MCF-7) and claudin-low (Hs 578T) breast cancer cell lines. We found that 7-Epi efficiently inhibited cell proliferation and migration of these cells; however MCF-7 was slightly more responsive than Hs 578T. Cell cycle analysis showed accumulation of cells at G0/G1 phase with drastic reduction of S population in treated cultures. This effect was associated to downregulation of CDKN1A (p21) and cyclin E in both cell lines. In addition, 7-Epi reduced cyclin D1 and p-ERK expression levels in MCF-7 cell line. Cytotoxic effect of 7-Epi on breast cancer cell lines was associated to its ability to increase BAX/BCL-2 ratio. In conclusion, our findings showed that 7-Epi is a promising antitumor agent against breast cancer by modulating critical regulators of the cell cycle and apoptosis.

Hexane Extract of Garcinia quaesita Fruits Induces Apoptosis in Breast Cancer Stem Cells Isolated from Triple Negative Breast Cancer Cell Line MDA-MB-231

Development of therapy resistance is a major clinical issue in breast cancer treatments. Breast cancer stem cells (bCSCs) have a clearly defined role in the development of breast cancer therapy resistance and tumor recurrence. Therefore, discovery of new treatment strategies to circumvent cancer therapy resistance and tumor recurrence by targeting bCSCs is desperately needed. Fruits of many Garcinia species are edible and, possess a range of health benefits. Garcinia quaesita, a species in the genus Garcinia, is endemic to Sri Lanka. Dried fruits of G. quaesita are commonly used to flavor dishes in Sri Lanka. The present study assessed the potential anticancer and apoptotic properties of G. quaesita fruit extracts in bCSCs using WST-1 cell proliferation assay, sphere formation assay, caspase 3/7 assay, real-time PCR and fluorescent and phase-contrast microscopy. DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (Ferric Reducing Anti-oxidant Power) assays were used as anti-oxidant assays. The hexane extract of G. quaesita fruits was found to mediate cytotoxicity in bCSCs through induction of apoptosis. Furthermore, the hexane extract showed free radical scavenging ability. This pilot investigation provides a rationale to consume G. quaesita fruits as an anticancer dietary supplement for breast cancer patients.

7-epi-Clusianone, a Multi-Targeting Natural Product with Potential Chemotherapeutic, Immune-Modulating, and Anti-Angiogenic Properties

Targeted therapies have changed the treatment of cancer, giving new hope to many patients in recent years. The shortcomings of targeted therapies including acquired resistance, limited susceptible patients, high cost, and high toxicities, have led to the necessity of combining these therapies with other targeted or chemotherapeutic treatments. Natural products are uniquely capable of synergizing with targeted and non-targeted anticancer regimens due to their ability to affect multiple cellular pathways simultaneously. Compounds which provide an additive effect to the often combined immune therapies and cytotoxic chemotherapies, are exceedingly rare. These compounds would however provide a strengthening bridge between the two treatment modalities, increasing their effectiveness and improving patient prognoses. In this study, 7-epi-clusianone was investigated for its anticancer properties. While previous studies have suggested clusianone and its conformational isomers, including 7-epi-clusianone, are chemotherapeutic, few cancer types have been demonstrated to exhibit sensitivity to these compounds and little is known about the mechanism. In this study, 7-epi-clusianone was shown to inhibit the growth of 60 cancer cell types and induce significant cell death in 25 cancer cell lines, while simultaneously modulating the immune system, inhibiting angiogenesis, and inhibiting cancer cell invasion, making it a promising lead compound for cancer drug discovery.

Prospect of natural products in glioma: A novel avenue in glioma management

Glioma is one of the most perplexing cancers because of its infiltrating nature, molecular signaling, and location in central nervous system. Blood-brain barrier acts as a natural barrier to the glioma making it difficult to access by conventional chemotherapy. Clinicians are using natural compounds or their derivatives for several diseases including different cancers. However, the feasibility of using natural compounds in glioma is not explored in details. Natural compounds can act over a wide variety of signaling pathways such as survival and metabolic pathways and induce cell death. Some of the natural agents have additional benefits of crossing biological barriers such as blood-brain barrier with ease having few or no impact on the surrounding healthy cells. All of these benefits make natural compounds a prospective candidate for the glioma management. This article evaluates the benefits of using natural compounds for glioma therapy and their possible mechanism of actions. We have discussed the natural compounds assessed currently for glioma therapy and proposed a few novel natural compounds with potential antiglioma effect based on their mechanism of action.

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.

A Rapid Determination and Quantification of Three Biologically Active Polyisoprenylated Benzophenones using Liquid Chromatography-Tandem Mass Spectrometry (MRM) Method in Five Garcinia species from Cameroon

Following investigation of Garcinia genus, a sensitive, rapid and simple reversed-phase high performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the identification and quantification of three polyisoprenylated benzophenones, garcinol (1), isogarcinol (2) and 7- epi-clusianone (3), in the extracts of five Garcinia species from Cameroon. The separation of those compounds was achieved on a RP-18 column using a solvent system consisting of a mixture of acetonitrile-water-formic acid as a mobile phase in a gradient elution mode. The identification of the three compounds was determined on a triple quadripole mass spectrometer with ESI interface operating in the negative mode. A multiple reaction monitoring (MRM) method was developed for the quantification of these polyisoprenylated benzophenones in the extracts of the Garcinia species. The method was validated through intra- and inter-day precision, with the relative standard deviation (RSD) less than 6%, limits of detection (LOD) and limits of quantification (LOQ) <1 ng. Overall recoveries ranged from 94% to 104%, with RSDs ranging from 0.8% to 4.5%. The results indicated that the fruits of G. preussii and the roots of G. brevipedicellata are good source of garcinol (1) and isogarcinol (2) respectively.

[Ru(pipe)(dppb)(bipy)]PF6: A novel ruthenium complex that effectively inhibits ERK activation and cyclin D1 expression in A549 cells

Lung cancer is the most frequent type of cancer worldwide. In Brazil, only 14% of the patients diagnosed with lung cancer survived 5years in the last decades. Although improvements in the therapeutic approach, it is relevant to identify new chemotherapeutic agents. In this framework, ruthenium metal compounds emerge as a promising alternative to platinum-based compounds once they displayed lower cytotoxicity and more selectivity for tumor cells. The present study aimed to evaluate the antitumor potential of innovative ruthenium(II) complex, [Ru(pipe)(dppb)(bipy)]PF₆ (PIPE) on A549 cells, which is derived from non-small cell lung cancer. Results demonstrated that PIPE effectively reduced the viability and proliferation rate of A549 cells. When PIPE was used at 9μM there was increase in G0/G1 cell population with concomitant reduction in frequency of cells in S-phase, indicating cell cycle arrest in G1/S transition. Antiproliferative activity of PIPE was associated to its ability of reducing cyclin D1 expression and ERK phosphorylation levels. Cytotoxic activity of PIPE on A549 cells was observed when PIPE was used at 18μM, which was associated to its ability of inducing apoptosis by intrinsic pathway. Taken together, the data demonstrated that PIPE is a promising antitumor agent and further in vivo studies should be performed.

Garcinol and Its Role in Chronic Diseases

The various bioactive compounds isolated from leaves and fruits of Garcinia sps plants, have been characterized and experimentally demonstrated to be anti-oxidant, anti-inflammatory and anti-cancer in nature. Garcinol, a polyisoprenylated benzophenone, obtained from plant Garcinia indica has been found to be an effective inhibitor of several key regulatory pathways (e.g., NF-kB, STAT3 etc.) in cancer cells, thereby being able to control malignant growth of solid tumours in vivo. Despite its high potential as an anti-neoplastic modulator of several cancer types such as head and neck cancer, breast cancer, hepatocellular carcinoma, prostate cancer, colon cancer etc., it is still in preclinical stage due to lack of systematic and conclusive evaluation of pharmacological parameters. While it is promising anti-cancer effects are being positively ascertained for therapeutic development, studies on its effectiveness in ameliorating other chronic diseases such as cardiovascular diseases, diabetes, allergy, neurodegenerative diseases etc., though seem favourable, are very recent and require in depth scientific investigation.

Cearoin Induces Autophagy, ERK Activation and Apoptosis via ROS Generation in SH-SY5Y Neuroblastoma Cells

Neuroblastomas are the most common solid extracranial tumors in childhood. We investigated the anticancer effect of cearoin isolated from Dalbergia odorifera in human neuroblastoma SH-SY5Y cells. SH-SY5Y cells were treated with various doses of cearoin. The viability was measured by MTT assay. DCFDA fluorescence assay and Griess assay were used for the measurement of intracellular reactive oxygen species (ROS) and nitric oxide (NO), respectively. Western blot analysis was performed to clarify the molecular pathway involved. Cearoin induced cell death in a dose-dependent manner. Cearoin increased the phosporylation of ERK, the conversion of LC3B-I to LC3B-II, decrease in Bcl2 expression, the activation of caspase-3, and the cleavage of PARP, indicating the induction of autophagy and apoptosis. Furthermore, cearoin treatment increased the production of ROS and NO. Co-treatment with the antioxidant N-acetylcysteine completely abolished cearoin-mediated autophagy, ERK activation and apoptosis, suggesting the critical role of ROS in cearoin-induced anticancer effects. Moreover, co-treatment with ERK inhibitor PD98059 partially reversed cearoin-induced cell death, indicating the involvement of ERK in cearoin anticancer effects. These data reveal that cearoin induces autophagy, ERK activation and apoptosis in neuroblastoma SH-SY5Y cells, which is mediated primarily by ROS generation, suggesting its therapeutic application for the treatment of neuroblastomas.

gem-Diprenylation of Acylphloroglucinols by a Fungal Prenyltransferase of the Dimethylallyltryptophan Synthase Superfamily

Aspergillus terreus aromatic prenyltransferase (AtaPT) catalyzes predominantly C-monoprenylation of acylphloroglucinols in the presence of different prenyl diphosphates. With dimethylallyl diphosphate (DMAPP) as prenyl donor, gem-diprenylated products 1D3, 2D3, and 3D3 were also detected. High conversion of 1D1 to 1D3, 2D1 to 2D3, and 3D1 to 3D3 was demonstrated by incubation with AtaPT and DMAPP. The first example of gem-diprenylation by a member of the dimethylallyltryptophan synthase superfamily is provided.