Anticancer Properties of Solamargine: A Systematic Review

Deregulation of New Cell Death Mechanisms in Leukemia

Hematological malignancies are among the top five most frequent forms of cancer in developed countries worldwide. Although the new therapeutic approaches have improved the quality and the life expectancy of patients, the high rate of recurrence and drug resistance are the main issues for counteracting blood disorders. Chemotherapy-resistant leukemic clones activate molecular processes for biological survival, preventing the activation of regulated cell death pathways, leading to cancer progression. In the past decade, leukemia research has predominantly centered around modulating the well-established processes of apoptosis (type I cell death) and autophagy (type II cell death). However, the development of therapy resistance and the adaptive nature of leukemic clones have rendered targeting these cell death pathways ineffective. The identification of novel cell death mechanisms, as categorized by the Nomenclature Committee on Cell Death (NCCD), has provided researchers with new tools to overcome survival mechanisms and activate alternative molecular pathways. This review aims to synthesize information on these recently discovered RCD mechanisms in the major types of leukemia, providing researchers with a comprehensive overview of cell death and its modulation.

Contribution of Sub-Saharan African medicinal plants to cancer research: Scientific basis 2013-2023

Cancer incidence and mortality rates are increasing worldwide. Cancer treatment remains a real challenge for African countries, especially in sub-Saharan Africa where funding and resources are very limited. High costs, side effects and drug resistance associated with cancer treatment have encouraged scientists to invest in research into new herbal cancer drugs. In order to identify potential anticancer plants for drug development, this review aims to collect and summarize anticancer activities (in vitro/in vivo) and molecular mechanisms of sub-Saharan African medicinal plant extracts against cancer cell lines. Scientific databases such as ScienceDirect, Google Scholar and PubMed were used to search for research articles published from January 2013 to May 2023 on anticancer medicinal plants in sub-Saharan Africa. The data were analyzed to highlight the cytotoxicity and molecular mechanisms of action of these listed plants. A total of 85 research papers covering 204 medicinal plant species were selected for this review. These plants come from 57 families, the most dominant being the plants of the family Amaryllidaceae (16), Fabaceae (14), Annonaceae (10), Asteraceae (10). Plant extracts exert their anticancer activity mainly by inducing apoptosis and stopping the cell cycle of cancer cells. Several plant extracts from sub-Saharan Africa therefore have strong potential for the search for original anticancer phytochemicals. Chemoproteomics, multi-omics, genetic editing technology (CRISPR/Cas9), combined therapies and artificial intelligence tools are cutting edge emerging technologies that facilitate the discovery and structural understanding of anticancer molecules of medicinal plants, reveal their direct targets, explore their therapeutic uses and molecular bases.

Extract of Astragali Radix and Solanum nigrum Linne regulates microglia and macrophage polarization and inhibits the growth and infiltration of C6 glioblastoma

ETHNOPHARMACOLOGICAL RELEVANCE

The polarization of glioma-associated microglia/macrophages (GAMs) affects the growth and infiltration of glioma. Astragali Radix (AR) and Solanum nigrum L. (SN) are traditional antitumor combinations in Chinese herbal medicine, but their roles and mechanisms against glioma are not yet clear.

AIM OF THE STUDY

The effects of AR and SN compound (ARSN) on the polarization of GAMs and glioma cells in vitro and in vivo were studied, providing new ideas for the treatment of glioma.

MATERIALS AND METHODS

The UPLC-QTOF-MS method was used to examine the quality of ARSN extracts. The effects of ARSN on proliferation, migration and apoptosis of C6 cells were investigated using CCK-8 assay, colony-forming assay, wound healing assay and flow cytometry. The impact of ARSN on the polarization of GAMs was verified by PCR, ELISA, and flow cytometry. In addition, a rat glioma model was established to assess the effects of ARSN on glioma growth, infiltration, and polarization of GAMs.

RESULTS

In vitro experiments, ARSN can effectively inhibit the proliferation and migration of C6 cells and promote apoptosis. In the rat orthotopic tumor model, ARSN also effectively inhibited tumor growth and infiltration. The SN part of ARSN has strong cytotoxicity. Meanwhile the AR part can effectively inhibit the M2 polarization of GAMs and chemokine production induced by tumor, promote the M1 phenotype of GAMs, and regulate the tumor immune microenvironment to indirectly kill glioma.

CONCLUSIONS

ARSN inhibited glioma growth both in vitro and in vivo. SN takes effect through direct cytotoxicity, while AR works by regulating GAMs polarization. ARSN extracts can be used as a potential agent for glioma treatment.

Solanum nigrum Linn.: Advances in anti-cancer activity and mechanism in digestive system tumors

Cancer has currently become a serious public health issue in many countries worldwide, and tumors of the digestive system have attracted an increasing number of researchers' due to their numerous types, high proportion and wide area of occurrence. While tumors of the digestive system suffer from high mortality rates, leading to untimely diagnosis and a poor prognosis, making it necessary to update current treatment approaches such as surgery, radiation therapy, and chemotherapy. This highlights the importance of exploring novel therapeutic ideas and targets. Traditional Chinese medicine has a long history of clinical use due to its low toxicity and multi-factor targeting of multiple pathways. As a kind of traditional Chinese herb, S. nigrum Linn. is highly regarded for its proven antitumor activity. The aim of this study was to comprehensively recapitulate and analyze the anti-cancer effects and molecular mechanisms of treatment of gastrointestinal tumors with S. nigrum Linn. extracts and related compounds, including classical signaling pathways mediated by them as well as noncoding RNA pathways associated with tumor suppression. Components that have been found to be responsible for the anti-cancer activity of S. nigrum Linn. include solanine, solasonine, solamargine, a-L-rhhamnopyranose, uttroside B, degalactotigonin, glycoprotein, and other compounds. The underlying mechanisms of anti-cancer activity reflected in this study include apoptosis, cell cycle arrest, autophagy, anti-angiogenesis, suppression of metastasis and invasion, immune escape, and increased sensitivity to radiotherapy. S. nigrum Linn. has great potential in the treatment of tumors of the digestive system, and through further clinical trials and pharmacological mechanisms it has the potential to become a uniform and standardized anti-tumor drug.

The Therapeutic Value of Solanum Steroidal (Glyco)Alkaloids: A 10-Year Comprehensive Review

Steroidal (glycol)alkaloids S(G)As are secondary metabolites made of a nitrogen-containing steroidal skeleton linked to a (poly)saccharide, naturally occurring in the members of the Solanaceae and Liliaceae plant families. The genus Solanum is familiar to all of us as a food source (tomato, potato, eggplant), but a few populations have also made it part of their ethnobotany for their medicinal properties. The recent development of the isolation, purification and analysis techniques have shed light on the structural diversity among the SGAs family, thus attracting scientists to investigate their various pharmacological properties. This review aims to overview the recent literature (2012-2022) on the pharmacological benefits displayed by the SGAs family. Over 17 different potential therapeutic applications (antibiotic, antiviral, anti-inflammatory, etc.) were reported over the past ten years, and this unique review analyzes each pharmacological effect independently without discrimination of either the SGA's chemical identity or their sources. A strong emphasis is placed on the discovery of their biological targets and the subsequent cellular mechanisms, discussing in vitro to in vivo biological data. The therapeutic value and the challenges of the solanum steroidal glycoalkaloid family is debated to provide new insights for future research towards clinical development.

Exploration of the Use of Natural Compounds in Combination with Chemotherapy Drugs for Tumor Treatment

Currently, chemotherapy is the main treatment for tumors, but there are still problems such as unsatisfactory chemotherapy results, susceptibility to drug resistance, and serious adverse effects. Natural compounds have numerous pharmacological activities which are important sources of drug discovery for tumor treatment. The combination of chemotherapeutic drugs and natural compounds is gradually becoming an important strategy and development direction for tumor treatment. In this paper, we described the role of natural compounds in combination with chemotherapeutic drugs in synergizing, reducing drug resistance, mitigating adverse effects and related mechanisms, and providing new insights for future oncology research.

An overview of natural products that modulate the expression of non-coding RNAs involved in oxidative stress and inflammation-associated disorders

Oxidative stress is a state in which oxidants are produced in excess in the body's tissues and cells, resulting in a biological imbalance amid the generation of reactive oxygen and nitrogen species (RONS) from redox reactions. In case of insufficient antioxidants to balance, the immune system triggers signaling cascades to mount inflammatory responses. Oxidative stress can have deleterious effects on major macromolecules such as lipids, proteins, and nucleic acids, hence, Oxidative stress and inflammation are among the multiple factors contributing to the etiology of several disorders such as diabetes, cancers, and cardiovascular diseases. Non-coding RNAs (ncRNAs) which were once referred to as dark matter have been found to function as key regulators of gene expression through different mechanisms. They have dynamic roles in the onset and development of inflammatory and oxidative stress-related diseases, therefore, are potential targets for the control of those diseases. One way of controlling those diseases is through the use of natural products, a rich source of antioxidants that have drawn attention with several studies showing their involvement in combating chronic diseases given their enormous gains, low side effects, and toxicity. In this review, we highlighted the natural products that have been reported to target ncRNAs as mediators of their biological effects on oxidative stress and several inflammation-associated disorders. Those natural products include Baicalein, Tanshinone IIA, Geniposide, Carvacrol/Thymol, Triptolide, Oleacein, Curcumin, Resveratrol, Solarmargine, Allicin, aqueous extract or pulp of Açai, Quercetin, and Genistein. We also draw attention to some other compounds including Zanthoxylum bungeanum, Canna genus rhizome, Fuzi-ganjiang herb pair, Aronia melanocarpa, Peppermint, and Gingerol that are effective against oxidative stress and inflammation-related disorders, however, have no known effect on ncRNAs. Lastly, we touched on the many ncRNAs that were found to play a role in oxidative stress and inflammation-related disorders but have not yet been investigated as targets of a natural product. Shedding more light into these two last points of shadow will be of great interest in the valorization of natural compounds in the control and therapy of oxidative stress- and inflammation-associated disorders.

Discovering the potential active ingredients of Qi-Yu-San-Long decoction for anti-oxidation, inhibition of non-small cell lung cancer based on the spectrum-effect relationship combined with chemometric methods

Qi-Yu-San-Long decoction (QYSLD), a traditional Chinese medicine (TCM) prescription, consisting of ten types of herbal medicine which has significant clinical efficacy in the treatment of non-small cell lung cancer (NSCLC). However, the bioactive ingredients of QYSLD remain unclear, due to their “multi-ingredients” and “multi-targets” features. This study aimed to construct a spectrum-effect correlation analysis model and screen the potential active components of QYSLD. A fingerprint method based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was developed and validated to obtain seventy common peaks of ten batches of QYSLD. The results of methodological evaluation, including precision, repeatability and stability, were less than 8.19%. In terms of linearity, eleven common components did not reach the linear standard (R² < 0.99), they were removed before spectrum-effect relationship analysis. After treated with ten batches of QYSLD, the results of DPPH and FRAP assays ranged from 1.59 to 5.50 mg mL⁻¹ and 143.83–873.83 μmol L⁻¹, respectively. Meanwhile, the cell viabilities of A549 cells treated with QYSLD samples ranged from 21.73% to 85.71%. The relative healing rates ranged from 21.50% to 44.46%. The number of migrated and invaded cells ranged from 12.00 to 68.67 and 7.67 to 27.00, respectively. Then, the potential active components of QYSLD were screened through spectrum-effect relationship constructed by grey correlation analysis (GRA), partial least squares regression (PLSR) and backpropagation neural network (BP-ANN). The results were as follow: 1) eight ingredients of QYSLD were relevant to DPPH free radical scavenging ability; 2) nine ingredients were relevant to FRAP; 3) six ingredients were relevant to inhibit the proliferation ability of A549 cells; 4) twenty-two ingredients were relevant to inhibit the horizontal migration ability; 5) five ingredients were relevant to inhibit the vertical migration ability; 6) twelve ingredients were relevant to inhibit the invasion ability. Confirmatory experiments showed that compared with the unscreened ingredients, the potential active ingredients screened by the spectrum-effect relationship had better antioxidant and anti-NSCLC effects. In general, this study found the potential active ingredients in QYSLD. Meanwhile, the established method provided a valuable reference model for the potential active ingredients of TCM.

The pathogenesis of liver cancer and the therapeutic potential of bioactive substances

Liver cancer is the third most common cause of cancer-related deaths in the world and has become an urgent problem for global public health. Bioactive substances are widely used for the treatment of liver cancer due to their widespread availability and reduced side effects. This review summarizes the main pathogenic factors involved in the development of liver cancer, including metabolic fatty liver disease, viral infection, and alcoholic cirrhosis, and focuses on the mechanism of action of bioactive components such as polysaccharides, alkaloids, phenols, peptides, and active bacteria/fungi. In addition, we also summarize transformation methods, combined therapy and modification of bioactive substances to improve the treatment efficiency against liver cancer, highlighting new ideas in this field.

Solamargine Inhibits the Development of Hypopharyngeal Squamous Cell Carcinoma by Decreasing LncRNA HOXA11-As Expression

Hypopharyngeal squamous cell carcinoma (HSCC) is one of the high mortality cancers with a poor prognosis, which is driving the development of new chemotherapeutic agents. We identified the anticancer effects of a natural compound, solamargine (SM), on FaDU cells and explored its mechanism in terms of non-coding RNA. It was observed that SM inhibited the proliferation of FaDU cells with an IC₅₀ of 5.17 μM. High-throughput sequencing data revealed that lncRNA HOXA11-AS was significantly downregulated in cells co-incubated with SM. Further assays demonstrated that SM-induced downregulation of lncRNA HOXA11-AS showed important implications for apoptosis. Given the properties of HOXA11-AS as a miR-155 sponge, we further confirmed that SM upregulated the expression of miR-155 in FaDU cells. C-Myc is a transcription factor that regulates cell differentiation and apoptosis, whose mRNA is considered to be targeted by miR-155. We showed that c-Myc expression was downregulated by SM and accompanied by increased apoptosis, which was consistent with the findings of transcriptome sequencing. Furthermore, SM administration suppressed xenograft tumor growth in a xenograft mouse model in vivo. In the light of the aforementioned findings, our results suggested that SM downregulated the expression of HOXA11-AS, which in turn induces apoptosis by downregulating c-Myc in FaDU, providing evidence for the anticancer effect of SM on HSCC and uncovering the effect of SM on non-coding RNAs as, at least partly, a mechanism of action.

In vitro anticancer properties of anthocyanins: A systematic review

Anthocyanins have been associated with beneficial effects on human health. Cancer has been one of the main public health issues due to its aggressiveness and high mortality rate. This systematic review aimed to address recent research (from January 2000 to September 2021) on the anticancer activity of anthocyanins assessed by in vitro assays. The selected studies revealed that anthocyanins have anticancer potential by inhibiting cancer cell viability and proliferation, controlling cell cycle, and promoting apoptosis.

Solamargine Alleviated UVB-Induced Inflammation and Melanogenesis in Human Keratinocytes and Melanocytes via the p38 MAPK Signaling Pathway, a Promising Agent for Post-inflammatory Hyperpigmentation

Post-inflammatory hyperpigmentation (PIH) is a common acquired pigmentary disorder occurring after skin inflammation or injury. Ultraviolet B irradiation could exaggerate PIH clinically due to its effect on promoting cutaneous inflammation and melanogenesis in keratinocytes and melanocytes, respectively. Solamargine (SM), a steroidal alkaloid glycoside extracted from Solanum undatum, significantly inhibits Ultraviolet B (UVB)-induced pro-inflammatory cytokines IL-1α, IL-1β, IL-8, and IFN-γ, as well as paracrine melanogenic factors ET-1, α-MSH, and bFGF in human keratinocytes. Additionally, SM significantly attenuated UVB-induced melanin synthesis in human epidermal melanocytes through down-regulation of tyrosinase activity and expression of MITF, TRP-1, TRP-2, and tyrosinase. SM exerted an anti-inflammatory effect in UVB-irradiated keratinocytes through the p38 MAPK/Nrf2/HO-1 signaling pathway. With its anti-inflammatory and whitening effect, SM may improve PIH through paracrine regulations of keratinocytes and direct action on melanocytes, making it a promising agent for PIH.

Solamargine Inhibits Prostate Cancer Cell Growth and Enhances the Therapeutic Efficacy of Docetaxel via Akt Signaling

Prostate cancer (PCa) has become a leading cause of cancer-associated incidence and mortality in men worldwide. However, most primary PCas relapse to castration-resistant PCa (CRPC) after androgen deprivation treatment. The current treatment for CRPC is based on chemotherapeutic drugs such as docetaxel, while the development of chemoresistance and severe side effects limit the therapeutic benefit. Solamargine, a natural alkaloid isolated from a traditional Chinese herbal medicine known as Solanum nigrum, exhibits antitumor activity in various human cancers. In this study, we demonstrated that solamargine substantially inhibited CRPC cell growth in a dose-dependent manner through the suppression of phosphoinositide 3-kinase (PI3K)/Akt signaling. Moreover, solamargine exhibited significant antitumor effects in mouse xenograft models. Bioinformatics analysis of docetaxel-resistant PCa cells indicated that the PI3K/Akt pathway mediated the chemoresistance of CRPC. Furthermore, solamargine significantly enhanced the efficacy of docetaxel in PCa cells. These results reveal the therapeutic potential of solamargine against human PCa.

Antitumor activity of solamargine in mouse melanoma model: relevance to clinical safety

Melanoma is the most aggressive type of skin cancer, and thus it is important to develop new drugs for its treatment. The present study aimed to examine the antitumor effects of solamargine a major alkaloid heteroside present in Solanum lycocarpum fruit. In addition solamargine was incorporated into nanoparticles (NP) of yttrium vanadate functionalized with 3-chloropropyltrimethoxysilane (YVO₄:Eu³⁺:CPTES:SM) to determine antitumor activity. The anti-melanoma assessment was performed using a syngeneic mouse melanoma model B16F10 cell line. In addition, systemic toxicity, nephrotoxic, and genotoxic parameters were assessed. Solamargine, at doses of 5 or 10 mg/kg/day administered subcutaneously to male C57BL/6 mice for 5 days, decreased tumor size and frequency of mitoses in tumor tissue, indicative of a decrease in cell proliferation. Treatments with YVO₄:Eu³⁺:CPTES:SM significantly reduced the number of mitoses in tumor tissue, associated with no change in tumor size. There were no apparent signs of systemic toxicity, nephrotoxicity, and genotoxicity initiated by treatments either with solamargine alone or plant alkaloid incorporated into NP. The animals treated with YVO₄:Eu³⁺:CPTES:SM exhibited significant increase in spleen weight accompanied by no apparent histological changes in all tissues examined. In addition, animals treated with solamargine (10 mg/kg/day) and YVO₄:Eu³⁺:CPTES:SM demonstrated significant reduction in hepatic DNA damage which was induced by tumor growth. Therefore, data suggest that solamargine may be considered a promising candidate in cancer therapy with no apparent toxic effects.

Solamargine inhibits the growth of hepatocellular carcinoma and enhances the anticancer effect of sorafenib by regulating HOTTIP-TUG1/miR-4726-5p/MUC1 pathway

Hepatocellular carcinoma (HCC) is one of the most common primary malignancies. Drug resistance has significantly prevented the clinical application of sorafenib (SF), a first‐line targeted medicine for the treatment of HCC. Solamargine (SM), a natural alkaloid, has shown potential antitumor activity, but studies about antitumor effect of SM are obviously insufficient in HCC. In the present study, we found that SM significantly inhibited the growth of HCC and enhanced the anticancer effect of SF. In brief, SM significantly inhibited the growth of HepG2 and Huh‐7 cells. The combination of SM and SF showed a synergistic antitumor effect. Mechanistically, SM downregulated the expression of long noncoding RNA HOTTIP and TUG1, followed by increasing the expression of miR‐4726‐5p. Moreover, miR‐4726‐5p directly bound to the 3′‐UTR region of MUC1 and decreased the expression of MUC1 protein. Overexpression of MUC1 partially reversed the inhibitory effect of SM on HepG2 and Huh‐7 cells viability, which suggested that MUC1 may be the key target in SM‐induced growth inhibition of HCC. More importantly, the combination of SM and SF synergistically restrained the expression of MUC1 protein. Taken together, our study revealed that SM inhibited the growth of HCC and enhanced the anticancer effect of SF through HOTTIP‐TUG1/miR‐4726‐5p/MUC1 signaling pathway. These findings will provide potential therapeutic targets and strategies for the treatment of HCC.

Pharmacological validation of Solanum mammosum L. as an anti-infective agent: Role of solamargine

ETHNOPHARMACOLOGICAL RELEVANCE

Fungal and bacterial infections remain a major problem worldwide, requiring the development of effective therapeutic strategies. Solanum mammosum L. (Solanaceae) ("teta de vaca") is used in traditional medicine in Peru to treat fungal infections and respiratory disorders via topical application. However, the mechanism of action remains unknown, particularly in light of its chemical composition.

MATERIALS AND METHODS

The antifungal activity of TDV was determined against Trichophyton mentagrophytes and Candida albicans using bioautography-TLC-HRMS to rapidly identify the active compounds. Then, the minimum inhibitory concentration (MIC) of the fruit crude extract and the active compound was determined to precisely evaluate the antifungal activity. Additionally, the effects of the most active compound on the formation of Pseudomonas aeruginosa biofilms and pyocyanin production were evaluated. Finally, a LC-HRMS profile and a molecular network of TDV extract were created to characterize the metabolites in the fruits' ethanolic extract.

RESULTS

Bioautography-TLC-HRMS followed by isolation and confirmation of the structure of the active compound by 1D and 2D NMR allowed the identification solamargine as the main compound responsible for the anti-Trichophyton mentagrophytes (MIC = 64 μg mL^-1) and anti-Candida albicans (MIC = 64 μg mL^-1) activities. In addition, solamargine led to a significant reduction of about 20% of the Pseudomonas aeruginosa biofilm formation. This effect was observed at a very low concentration (1.6 μg mL^-1) and remained fairly consistent regardless of the concentration. In addition, solamargine reduced pyocyanin production by about 20% at concentrations of 12.5 and 50 μg mL^-1. Furthermore, the LC-HRMS profiling of TDV allowed us to annotate seven known compounds that were analyzed through a molecular network.

CONCLUSIONS

Solamargine has been shown to be the most active compound against T. mentoagrophytes and C. albicans in vitro. In addition, our data show that this compound affects significantly P. aeruginosa pyocyanin production and biofilm formation in our conditions. Altogether, these results might explain the traditional use of S. mammosum fruits to treat a variety of fungal infections and respiratory disorders.

Anticancer activity of monoterpenes: a systematic review

Secondary metabolites have been recognized for centuries as medicinal agents, in particular monoterpenes which have been the target of research in the discovery of antineoplastic drugs, as they have potential antitumor effect and low toxicity and are used as additives in foods and cosmetics. Another advantage of monoterpenes is structural diversity, which gives greater plasticity when interacting with cells. The purpose of this review was to summarize and critically discuss the anticancer potential of monoterpenes and their respective mechanisms of action. A systematic review of articles in the MEDLINE/PubMed, Web of Science, Scopus and Science Direct electronic databases was independently conducted by three reviewers using the combination of the following keywords: monoterpenes AND anticancer AND in vitro. Restriction in selecting articles followed pre-established inclusion and exclusion criteria by the reviewers, and also a time limitation with works published between 2015 and 2019 being selected. In total, 39 works were deemed eligible for inclusion in the final review. Monoterpenes have cytotoxic activity in a wide variety of tumor cell lines, and mainly appear to exert this effect by inducing apoptosis caused by oxidative stress. In addition, improved use of monoterpenes when used in drug delivery systems and the synergistic effect with conventional chemotherapeutic drugs are reported. These findings validate this class of compounds as a promising source of chemotherapeutic drugs yet to be explored.

Current Insight into the Therapeutic Potential of Phytocompounds and their Nanoparticle-based Systems for Effective Management of Lung Cancer

Lung cancer is the second most common cancer and the primary cause of cancer-related death in both men and women worldwide. Due to diagnosis at an advanced stage, it is associated with high mortality in the majority of patients. At present, various treatment approaches are available such as chemotherapy, surgery, and radiotherapy. However, all these approaches usually cause serious side effects like degeneration of normal cells, bone marrow depression, alopecia, extensive vomiting, etc. To overcome the aforementioned problems, researchers have focused on the alternative therapeutic approach in which various natural compounds are reported, which possessed anti-lung cancer activity. Phytocompounds exhibit their anti-lung cancer activity via targeting various cell-signaling pathways, apoptosis, cell cycle arrest, and regulating antioxidant status and detoxification. Apart from the excellent anti-cancer activity, clinical administration of phytocompounds is confined because of their high lipophilicity and low bioavailability. Therefore, researchers show their concern in the development of a stable, safe, and effective approach of treatment with minimal side effects by the development of nanoparticle-based delivery of these phytocompounds to the target site. Targeted delivery of phytocompound through nanoparticles overcomes the aforementioned problems. In this article, the molecular mechanism of phytocompounds, their emerging combination therapy, and their nanoparticles-based delivery systems in the treatment of lung cancer have been discussed.

Synthetic Strategies to Access Heteroatomic Spirocentres Embedded in Natural Products

The spirocyclic motif is abundant in natural products and provides an ideal three-dimensional template to interact with biological targets. With significant attention historically expended on the synthesis of flat-heterocyclic compound libraries, methods to access the less-explored three-dimensional medicinal-chemical space will continue to increase in demand. Herein, we highlight by reaction class the common strategies used to construct the spirocyclic centres embedded in a series of well-studied natural products.

1 Introduction

2 Cycloadditions

3 Palladium-Catalysed Coupling Reactions

4 Conjugate Additions

5 Imines, Aminals, and Hemiaminal Ethers

6 Mannich-Type Reactions

7 Oxidative Dearomatisation

8 Alkylation

9 Organometallic Additions

10 Conclusions

A review on traditionally used South African medicinal plants, their secondary metabolites and their potential development into anticancer agents

ETHNOPHARMACOLOGICAL RELEVANCE

Approximately 70% of anticancer drugs were developed or derived from natural products or plants. Southern Africa boasts an enormous floral diversity with approximately 22,755 plant species with an estimated 3000 used as traditional medicines. In South Africa more than 27 million individuals rely on traditional medicine for healthcare. The use of South African plants for the treatment of cancer is poorly documented, however there is potential to develop anticancer agents from these plants. Limited ethnobotanical studies report the use of plants for cancer treatment in traditional medicine. Plants growing in tropical or subtropical regions, such as in South Africa, produce important secondary metabolites as a protective mechanism, which could be used to target various factors that play a key role in carcinogenesis.

AIMS

The aim was to collate information from primary ethnobotanical studies on South African plants traditionally used for the treatment of cancer. Evaluation of literature focused on traditionally used plants that have been tested for their in vitro activity against cancer cells. Secondary metabolites, previously identified within these plant species, were also included for discussion regarding their activity against cancer. The toxicity was evaluated to ascertain the therapeutic potential in further studies. Additionally, the aim was to highlight where a lack of reports were found regarding plant species with potential activity and to substantiate the need for further testing.

MATERIALS AND METHODS

A review of ethnobotanical surveys conducted in South Africa for plants used in the treatment of cancer was performed. Databases such as Science Direct, PubMed and Google Scholar, university repositories of master's dissertations and PhD theses, patents and books were used. Plant species showing significant to moderate activity were discussed regarding their toxicity. Compounds identified within these species were discussed for their activity against cancer cells and toxicity. Traditionally used plants which have not been scientifically validated for their activity against cancer were excluded.

RESULTS

Twenty plants were documented in ethnobotanical surveys as cancer treatments. Numerous scientific reports on the potential in vitro activity against cancer of these plants and the identification of secondary metabolites were found. Many of the secondary metabolites have not been tested for their activity against cancer cells or mode of action and should be considered for future studies. Lead candidates, such as the sutherlandiosides, sutherlandins, hypoxoside and pittoviridoside, were identified and should be further assessed. Toxicity studies should be included when testing plant extracts and/or secondary metabolites for their potential against cancer cells to give an indication of whether further analysis should be conducted.

CONCLUSION

There is a need to document plants used traditionally in South Africa for the treatment of cancer and to assess their safety and efficacy. Traditionally used plants have shown promising activity highlighting the importance of ethnobotanical studies and traditional knowledge. There are many opportunities to further assess these plants and secondary metabolites for their activity against cancer and their toxic effects. Pharmacokinetic studies are also not well documented within these plant extracts and should be included in studies when a lead candidate is identified.

Solanum Nigrum Fruit Extract Increases Toxicity of Fenitrothion-A Synthetic Insecticide, in the Mealworm Beetle Tenebrio Molitor Larvae

Synthetic insecticides are widely used for crop protection both in the fields and in the food stored facilities. Due to their toxicity, and assumptions of Integrated Pest Management, we conducted two independent experiments, where we studied the influence of Solanum nigrum unripe fruit extract on the toxicity of an organophosphorus insecticide fenitrothion. In the first variant of the experiment, Tenebrio molitor larvae were fed with blended fenitrothion (LC50) and the extract in four concentrations (0.01, 0.1, 1 and 10%) in ratio 1:1 for 3 days. In the second variant, a two-day application of fenitrothion (LC40) was preceded by a one-day extract treatment. The first variant did not show any increase in lethality compared to fenitrothion; however, ultrastructure observations exhibited swollen endoplasmic reticulum (ER) membranes in the midgut and nuclear and cellular membranes in the fat body, after application of blended fenitrothion and extract. An increased amount of heterochromatin in the fat body was observed, too. In the second variant, pre-treatment of the extract increased the lethality of larvae, decreased the level of glycogen and lipids in the fat body and disrupted integrity of midgut cellular membranes. S. nigrum extract, applied prior to fenitrothion treatment can be a factor increasing fenitrothion toxicity in T. molitor larvae. Thus, this strategy may lead to decreased emission of synthetic insecticides to the environment.

Chemoresistant ovarian cancer enhances its migration abilities by increasing store-operated Ca2+ entry-mediated turnover of focal adhesions

Background

Among gynecological cancers, ovarian carcinoma has the highest mortality rate, and chemoresistance is highly prevalent in this cancer. Therefore, novel strategies are required to improve its poor prognosis. Formation and disassembly of focal adhesions are regulated dynamically during cell migration, which plays an essential role in cancer metastasis. Metastasis is intricately linked with resistance to chemotherapy, but the molecular basis for this link is unknown.

Methods

Transwell migration and wound healing migration assays were used to analyze the migration ability of ovarian cancer cells. Real-time recordings by total internal reflection fluorescence microscope (TIRFM) were performed to assess the turnover of focal adhesions with fluorescence protein-tagged focal adhesion molecules. SOCE inhibitors were used to verify the effects of SOCE on focal adhesion dynamics, cell migration, and chemoresistance in chemoresistant cells.

Results

We found that mesenchymal-like chemoresistant IGROV1 ovarian cancer cells have higher migration properties because of their rapid regulation of focal adhesion dynamics through FAK, paxillin, vinculin, and talin. Focal adhesions in chemoresistant cells, they were smaller and exhibited strong adhesive force, which caused the cells to migrate rapidly. Store-operated Ca²⁺ entry (SOCE) regulates focal adhesion turnover, and cell polarization and migration. Herein, we compared SOCE upregulation in chemoresistant ovarian cancer cells to its parental cells. SOCE inhibitors attenuated the assembly and disassembly of focal adhesions significantly. Results of wound healing and transwell assays revealed that SOCE inhibitors decreased chemoresistant cell migration. Additionally, SOCE inhibitors combined with chemotherapeutic drugs could reverse ovarian cancer drug resistance.

Conclusion

Our findings describe the role of SOCE in chemoresistance-mediated focal adhesion turnover, cell migration, and viability. Consequently, SOCE might be a promising therapeutic target in epithelial ovarian cancer.

Graphical abstract

Alkaloids from Traditional Chinese Medicine against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has become one of the major diseases that are threatening human health in the 21st century. Currently there are many approaches to treat liver cancer, but each has its own advantages and disadvantages. Among various methods of treating liver cancer, natural medicine treatment has achieved promising results because of their superiorities of high efficiency and availability, as well as low side effects. Alkaloids, as a class of natural ingredients derived from traditional Chinese medicines, have previously been shown to exert prominent anti-hepatocarcinogenic effects, through various mechanisms including inhibition of proliferation, metastasis and angiogenesis, changing cell morphology, promoting apoptosis and autophagy, triggering cell cycle arrest, regulating various cancer-related genes as well as pathways and so on. As a consequence, alkaloids suppress the development and progression of liver cancer. In this study, the mechanisms of representative alkaloids against hepatocarcinoma in each class are described systematically according to the structure classification, which mainly divides alkaloids into piperidine alkaloids, isoquinoline alkaloids, indole alkaloids, terpenoids alkaloids, steroidal alkaloids and other alkaloids. Besides using them alone, synergistic effects created together with other chemotherapy drugs and some special preparation methods also have been demonstrated. In this review, we have summarized the potential roles of several common alkaloids in the prevention and treatment of HCC, by revising the preclinical studies, highlighting the potential applications of alkaloids when they function as a therapeutic choice for HCC treatment, and integrating them into clinical practices.

Novel reciprocal interaction of lncRNA HOTAIR and miR-214-3p contribute to the solamargine-inhibited PDPK1 gene expression in human lung cancer

Solamargine (SM) has been shown to have anti‐cancer properties. However, the underlying mechanism involved remains undetermined. We showed that SM inhibited the growth of non‐small cell lung cancer (NSCLC) cells, which was enhanced in cells with silencing of long non‐coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR), while it overcame by overexpression of HOTAIR. In addition, SM increased the expression of miR‐214‐3p and inhibited 3‐phosphoinositide‐dependent protein kinase‐1 (PDPK1) gene expression, which was strengthened by miR‐214‐3p mimics. Intriguingly, HOTAIR could directly bind to miR‐214‐3p and sequestered miR‐214‐3p from the target gene PDPK1. Intriguingly, overexpression of PDPK1 overcame the effects of SM on miR‐214‐3p expressions and neutralized the SM‐inhibited cell growth. Similar results were observed in vivo. In summary, our results showed that SM‐inhibited NSCLC cell growth through the reciprocal interaction between HOTAIR and miR‐214‐3p, which ultimately suppressed PDPK1 gene expression. HOTAIR effectively acted as a competing endogenous RNA (ceRNA) to stimulate the expression of target gene PDPK1. These complex interactions and feedback mechanisms contribute to the overall effect of SM. This unveils a novel molecular mechanism underlying the anti‐cancer effect of SM in human lung cancer.

Solamargine inhibits proliferation and promotes apoptosis of CM-319 human chordoma cells through suppression of notch pathway

Background

Solamargine (SM), which represents a natural steroid alkaloid glycoside compound and a cytotoxic agent, has been proved to enhance the sensitivity of lung cancer cells to tumor necrosis factors (TNFs). In this study, we aimed to investigate the roles and mechanisms of SM in chordoma.

Methods

Cell viability, proliferation, apoptosis and cell cycle were measured by cell counting Kit-8 (CCK-8) assay, 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling and flow cytometry (FCM), respectively. Western blot and quantitative real-time reverse transcription PCR (qRT-PCR) assays were performed to detect the expressions of related mRNAs and proteins.

Results

The results revealed that SM distinctly suppressed the proliferation of CM-319 cells. SM significantly induced the CM-319 cells apoptosis through up-regulating the expression levels of Caspase-3/8/9. The cell cycle of CM-319 cells was blocked by SM in G1 phase. Moreover, SM could significantly suppress the Notch pathway in CM-319 cells.

Conclusions

In conclusion, SM suppressed the proliferation and enhanced the apoptosis ability of CM-319 cells via suppressing the Notch pathway. The results suggested that SM might be a novel therapeutic agent and supported the utilization of SM in chordoma.

Solamargine inhibits gastric cancer progression by regulating the expression of lncNEAT1_2 via the MAPK signaling pathway

Solamargine, a derivative from the steroidal solasodine in Solanum species, has exhibited anticancer activities in numerous types of cancer; however, its role in gastric cancer (GC) remains unknown. In the present study, it was demonstrated that Solamargine suppressed the viability of five gastric cancer cell lines in a dose‑dependent manner and induced notable alterations in morphology. Treatment with Solamargine promoted cell apoptosis (P<0.01). Solamargine increased the expression of long noncoding RNA (lnc) p53 induced transcript and lnc nuclear paraspeckle assembly transcript 1 (NEAT1)_2 (P<0.01) in GC by reducing the phosphorylation of extracellular signal‑regulated kinase (Erk)1/2 mitogen‑activated protein kinase (MAPK). To gain insight into the potential mechanism, an Erk1/2 inhibitor (U0126) was applied. The results revealed that lncNEAT1_2 expression levels increased, which was consistent with the effects of Solamargine. Downregulation of lncNEAT1_2 in GC cells revealed no effect on the expression levels of total Erk1/2 and, and counteracted the effect of Solamargine. Solamargine was observed to increase the expression of lncNEAT1_2 via the Erk1/2 MAPK signaling pathway. Of note, the knockdown of lncNEAT1_2 reduced the inhibitory effect of Solamargine (P<0.05). Additionally, experiments in vivo and in primary GC cells from patients demonstrated that Solamargine significantly suppressed tumor growth (P<0.05). In vivo analysis of a xenograft mouse model further supported that Solamargine could induce the apoptosis of cancer cells in tumor tissue as observed by a terminal deoxynucleotidyl transferase‑mediated dUTP‑biotin nick end labeling and H&E staining (P<0.05). Experiments in primary GC cells from patients verified the anti‑tumor effect of Solamargine. In summary, the findings of the present study indicated that Solamargine inhibited the progression of GC by regulating lncNeat1_2 via the MAPK pathway.

Degalactotigonin, a Steroidal Glycoside from Solanum nigrum, Induces Apoptosis and Cell Cycle Arrest via Inhibiting the EGFR Signaling Pathways in Pancreatic Cancer Cells

Degalactotigonin (1) and three other steroidal compounds solasodine (2), O-acetyl solasodine (3), and soladulcoside A (4) were isolated from the methanolic extract of Solanum nigrum, and their chemical structures were elucidated by spectroscopic analyses. The isolated compounds were evaluated for cytotoxic activity against human pancreatic cancer cell lines (PANC1 and MIA-PaCa2) and lung cancer cell lines (A549, NCI-H1975, and NCI-H1299). Only degalactotigonin (1) showed potent cytotoxicity against these cancer cell lines. Compound 1 induced apoptosis in PANC1 and A549 cells. Further study on its mechanism of action in PANC1 cells demonstrated that 1 significantly inhibited EGF-induced proliferation and migration in a concentration-dependent manner. Treatment of PANC1 cells with degalactotigonin induced cell cycle arrest at G0/G1 phase. Compound 1 induced downregulation of cyclin D1 and upregulation of p21 in a time- and concentration-dependent manner and inhibited EGF-induced phosphorylation of EGFR, as well as activation of EGFR downstream signaling molecules such as Akt and ERK.

African Nightshade (Solanum scabrum Mill.): Impact of Cultivation and Plant Processing on Its Health Promoting Potential as Determined in a Human Liver Cell Model

Plant cultivation and processing may impact nutrient and phytochemical content of vegetables. The present study aimed at determining the influence of cultivation and processing on the health promoting capacity of African nightshade (Solanum scabrum Mill.) leaves, an indigenous vegetable, rich in nutrients and phytochemicals. Anti-genotoxicity against the human liver carcinogen aflatoxin B1 (AFB₁) as determined by the comet assay and radical oxygen species (ROS) scavenging capacity of ethanolic and aqueous extracts were investigated in human derived liver (HepG2) cells. ROS scavenging activity was assessed using electron paramagnetic spin resonance and quantification of ARE/Nrf2 mediated gene expression. The cultivation was done under different environmental conditions. The processing included fermentation and cooking; postharvest ultraviolet irradiation (UV-C) treatment was also investigated. Overall, S. scabrum extracts showed strong health promoting potential, the highest potential was observed with the fermented extract, which showed a 60% reduction of AFB₁ induced DNA damage and a 38% reduction in FeSO₄ induced oxidative stress. The content of total polyphenols, carotenoids and chlorophylls was indeed affected by cultivation and processing. Based on the present in vitro findings consumption of S. scabrum leaves could be further encouraged, preferentially after cooking or fermentation of the plant.