Targeting signal transducer and activator of transcription 3 contributes to the solamargine-inhibited growth and -induced apoptosis of human lung cancer cells

Solamargine improves the therapeutic efficacy of anti-PD-L1 in lung adenocarcinoma by inhibiting STAT1 activation

OBJECTIVE

The effect of solamargine on lung adenocarcinoma and its effect on STAT1 signaling pathway mediated immune escape were studied through network pharmacology and in vitro and in vivo experiments.

METHODS

The solamargine targets were screened using the TCMSP and the LUAD targets were screened using the GeneCard, OMIM, PharmGkb, TTD and DrugBank databases. PPI network analysis and target prediction were performed using GO and KEGG. Colony formation assay, EDU staining, wound healing, transwell assay, Hoechst and flow cytometry were used to detect the effects of solamargine on the proliferation, migration and apoptosis of LUAD. Western blotting (WB) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to detect P-STAT1 and PD-L1 expression. And immunofluorescence was used to detect P-STAT1 expression. In vivo experiments, C57BL/6 mice were divided into control group, low concentration group, high concentration group, positive control group and combination group. Every other day, following seven consecutive doses, the size of the tumor was assessed. Finally, the expressions of P-STAT1, STAT1, PD-L1 and apoptosis index proteins were detected by WB.

RESULTS

The anti-LUAD effect of solamargine was found by wound healing, colony formation assay, transwell assay, hoechst and EdU staining. The results of network pharmacological analysis showed that solamargine could suppress STAT1 expression level. Further enrichment assay of STAT1 showed that STAT1 was associated with immune-related pathways. In addition, molecular signal analysis by WB and RT-qPCR indicated that solamargine could reduce the expression levels of P-STAT1 and PD-L1 in a concentration-dependent manner. According to the results of in vivo assays, combination of solamargine and immune checkpoint inhibitors (ICIs) durvalumab could significantly inhibit the growth of Lewis transplanted tumors in C57BL/6 mice, and no toxic side effect was recoded.

CONCLUSION

These results indicated that solamargine could inhibit the proliferation and promote the apoptosis of LUAD. It also could reduce the expression level of P-STAT1 protein and inhibit the expression level of PD-L1. At the same time, the combination with the ICIs can better block the expression of PD-L1 in cells, thereby inhibiting the immune escape pathway of tumor cells and achieving anti-tumor effects. This study proposed a novel combined therapeutic approach, involving the inhibition of STAT1 by solamargine in conjunction with ICIs.

Unleashed Treasures of Solanaceae: Mechanistic Insights into Phytochemicals with Therapeutic Potential for Combatting Human Diseases

Plants that possess a diverse range of bioactive compounds are essential for maintaining human health and survival. The diversity of bioactive compounds with distinct therapeutic potential contributes to their role in health systems, in addition to their function as a source of nutrients. Studies on the genetic makeup and composition of bioactive compounds have revealed them to be rich in steroidal alkaloids, saponins, terpenes, flavonoids, and phenolics. The Solanaceae family, having a rich abundance of bioactive compounds with varying degrees of pharmacological activities, holds significant promise in the management of different diseases. Investigation into Solanum species has revealed them to exhibit a wide range of pharmacological properties, including antioxidant, hepatoprotective, cardioprotective, nephroprotective, anti-inflammatory, and anti-ulcerogenic effects. Phytochemical analysis of isolated compounds such as diosgenin, solamargine, solanine, apigenin, and lupeol has shown them to be cytotoxic in different cancer cell lines, including liver cancer (HepG2, Hep3B, SMMC-772), lung cancer (A549, H441, H520), human breast cancer (HBL-100), and prostate cancer (PC3). Since analysis of their phytochemical constituents has shown them to have a notable effect on several signaling pathways, a great deal of attention has been paid to identifying the biological targets and cellular mechanisms involved therein. Considering the promising aspects of bioactive constituents of different Solanum members, the main emphasis was on finding and reporting notable cultivars, their phytochemical contents, and their pharmacological properties. This review offers mechanistic insights into the bioactive ingredients intended to treat different ailments with the least harmful effects for potential applications in the advancement of medical research.

Solamargine induces apoptosis of human renal carcinoma cells via downregulating phosphorylated STAT3 expression

Solamargine (SM), an active compound derived from Solanum nigrum, triggers apoptosis and inhibits the metastatic and oxidative activities of various types of tumor cells. However, the effect of SM on human renal carcinoma cells remains unknown. In the present study, the molecular mechanisms underlying the antitumor effects of SM on ACHN and 786-O cells were elucidated. Specifically, MTT and colony formation assays were conducted to evaluate the impact of SM treatment on the proliferation of ACHN and 786-O cells, and flow cytometry was conducted to determine the influence of SM on the apoptosis rates of these cells. In addition, the expression of target proteins was determined by western blotting. The results revealed that SM not only inhibited cell viability but also promoted the apoptosis of ACHN and 786-O cells in a time- and dose-dependent manner. Moreover, treatment of ACHN and 786-O cells with SM significantly enhanced the caspase-3, caspase-8 and caspase-9 activities. Furthermore, SM downregulated the expression of phosphorylated signal transducer and activator of transcription-3 (p-STAT3) and Bcl-2 but increased the expression of cleaved caspase-3, -8, -9 and Bax. BAY2353, a p-STAT3 inhibitor, inhibited the viability of ACHN and 786-O cells, increased the expression of cleaved caspase-9 and Bax and decreased the expression of p-STAT3 and Bcl-2. Further experiments demonstrated that SM inhibited tumor growth in xenograft nude mice without causing specific toxicity to the major organs. Collectively, these findings indicated that SM not only inhibited the viability but also promoted the apoptosis of ACHN and 786-O cells, through a mechanism involving downregulation of p-STAT3 expression.

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.

Identification of solamargine as a cisplatin sensitizer through phenotypical screening in cisplatin-resistant NSCLC organoids

Although Cisplatin (DDP) is a widely used first-line chemotherapy medication, DDP resistance is one of the main causes of treatment failure in advanced lung cancer. Therefore, it is urgent to identify DDP sensitizers and investigate the underlying molecular mechanisms. Here we utilized DDP-resistant organoids established from tumor biopsies of patients with relapsed lung cancers. In this study, we identified Solamargine as a potential DDP sensitizer through screening a natural product library. Mechanically, Solamargine induced G0/G1-phase arrest and apoptosis in DDP-resistant lung cancer cell lines. Gene expression analysis and KEGG pathway analysis indicated that the hedgehog pathway was suppressed by Solamargine. Moreover, Gli responsive element (GRE) reporter gene assay and BODIPY-cyclopamine binding assay showed that Solamargine inhibited the hedgehog pathway via direct binding to SMO protein. Interestingly, Solamargine and DDP showed a synergetic effect in inhibiting DDP-resistant lung cancer cell lines. Taken together, our work herein revealed Solamargine as a hedgehog pathway inhibitor and DDP-sensitizer, which might provide a new direction for further treatment of advanced DDP-resistant lung cancer patients.

Identification of the constituents and the cancer-related targets of the fruit of Solanum nigrum based on molecular docking and network pharmacology

The fruit of Solanum nigrum (FSN) exhibited a variety of biological activities. However, the chemical composition of the fruit, as well as the steroidal alkaloids responsible for the bioactivity and the mechanism of action need to be further studied. The ultrahigh performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q Orbitrap HRMS) and nuclear magnetic resonance (NMR) were applied to investigate the chemical composition of FSN, which led to the identification of 170 compounds, including 12 amino acids, 4 caffeoylquinic acids, 2 flavonols, 114 steroid alkaloids, 5 steroid saponins and 33 other structure compounds. The network pharmacology showed that the anticancer effect of 14 steroid alkaloids was probably acting through 99 biological targets. Among them, 11 alkaloids and 11 targets probably played the important role based on the results of molecular docking. This study enriched our knowledge about the chemical composition of FSN, as well as the anticancer mechanism of steroidal alkaloids in FSN.

The regulation and interaction of colon cancer-associated transcript-1 and miR7-5p contribute to the inhibition of SP1 expression by solamargine in human nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a common head and neck malignancy with higher incidence in Southern China and Southeast Asia. Solamargine (SM), a steroidal alkaloid glycoside, has been shown to have anticancer properties. However, the underlying mechanism involved remains undetermined. In this study, we showed that SM inhibited the growth of NPC cells. Mechanistically, we found that solamargine decreased lncRNA colon cancer-associated transcript-1 (CCAT1) and increased miR7-5p expression. There was a reciprocal interaction of CCAT1 and miR7-5p. In addition, SM inhibited the expression of SP1 protein and promoter activity, which was strengthened by miR7-5p mimics and inhibited by overexpressed CCAT1. MiR7-5p could bind to 3'-UTR of SP1 and attenuated SP1 gene expression. Exogenously expressed SP1 feedback resisted SM-increased miR7-5p expression and more importantly reversed SM-inhibited growth of NPC cells. Finally, SM inhibited NPC tumor growth in vivo. Collectively, our results show that SM inhibits the growth of NPC cells through reciprocal regulation of CCAT1 and miR7-5p, followed by inhibition of SP1 gene expression in vitro and in vivo. The interregulation and correlation among CCAT1, miR7-5p and SP1, and the feedback regulatory loop unveil the novel molecular mechanism underlying the overall responses of SM in anti-NPC.

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.

Emerging themes of regulation of oncogenic proteins by Solanum nigrum and its bioactive molecules in different cancers

Research over the decades has sequentially and systematically provided a near-complete resolution of multifaceted and therapeutically challenging nature of cancer. Drug discovery from plants has enjoyed a renaissance in the past few years. Natural products have provided many of the lead structures, which are currently being used as templates for the design and synthesis of novel compounds with biologically enhanced properties. With the maturity and diversification of technologies, there is a growing need to design high-throughput functional assays for the evaluation of the myriad of compounds being catalogued. This review sheds light on the tumor suppressive properties of Solanum nigrum and its bioactive ingredients. Several worthy of mention include uttroside B, solanine, solamargine, and physalins, which have been tested for efficacy in cancer cell lines and xenografted mice. We have summarized the most recent findings related to S. nigrum-mediated regulation of intracellular protein network in different cancers. α-Solanine, an active component of S. nigrum, is involved in the regulation of microRNA-21 (miRNA-21) (oncogenic) and miRNA-138 (tumor suppressor) in prostate cancer. However, this is the only available evidence that gives us a clue related to the tumor suppressive effects exerted by components of S. nigrum at a posttranscriptional level. More interestingly, S. nigrum and its components exerted inhibitory effects on different pathways including PI3K/AKT, JAK-STAT, VEGF/VEGFR, and matrix metalloproteinases in different cancers. We also provide an overview of new tools, methodologies, and approaches, which will allow researchers to extract as much information as possible out of the tremendous data sets currently being generated. The use of computational tools will be helpful in processing structurally complex natural products and also in prediction of their macromolecular targets.

OSU-A9 inhibits pancreatic cancer cell lines by modulating p38-JAK-STAT3 signaling

Pancreatic cancer is an aggressive malignancy that is the fourth leading cause of death worldwide. Since there is a dire need for novel and effective therapies to improve the poor survival rates of advanced pancreatic cancer patients, we analyzed the antitumor effects of OSU-A9, an indole-3-carbinol derivative, on pancreatic cancer cell lines in vitro and in vivo. OSU-A9 exhibited a stronger antitumor effect than gemcitabine on two pancreatic cancer cell lines, including gemcitabine-resistant PANC-1 cells. OSU-A9 treatment induced apoptosis, the down-regulation of Akt phosphorylation, up-regulation of p38 phosphorylation and decreased phosphorylation of JAK and STAT3. Cell migration and invasiveness assays showed that OSU-A9 reduced cancer cell aggressiveness and inhibited BxPC-3 xenograft growth in nude mice. These results suggest that OSU-A9 modulates the p38-JAK-STAT3 signaling module, thereby inducing cytotoxicity in pancreatic cancer cells. Continued evaluation of OSU-A9 as a potential therapeutic agent for pancreatic cancer thus appears warrented.

Interplay of DNA methyltransferase 1 and EZH2 through inactivation of Stat3 contributes to β-elemene-inhibited growth of nasopharyngeal carcinoma cells

β-elemene, a compound extracted from Curcuma wenyujin plant, exhibits anticancer activity in many cancer types. However, the detailed mechanism by which β-elemene inhibits growth of nasopharyngeal carcinoma (NPC) cells remains unknown. We showed that β-elemene reduced phosphorylation of signal transducer and activator of transcription 3 (Stat3), and protein expressions of DNA methyltransferase 1 (DNMT1) and enhancer of zeste homolog 2 (EZH2). Exogenously expressed Stat3 antagonized the effect of β-elemene on DNMT1 and EZH2 expressions. Furthermore, overexpressions of DNMT1 and EZH2 reversed the effect of β-elemene on phosphorylation of Stat3 and cell growth inhibition. Intriguingly, exogenously expressed DNMT1 overcame β-elemene-inhibited EZH2 protein expression and promoter activity. On the contrary, silencing of EZH2 and DNMT1 genes feedback strengthened the effect of β-elemene on phosphorylation of Stat3. Consistent with this, β-elemene inhibited tumor growth, phosphorylation of Stat3, expressions of DNMT1 and EZH2 in a mouse xenograft model. Collectively, this study shows that β-elemene inhibits NPC cell growth via inactivation of Stat3, and reduces DNMT1 and EZH2 expressions. The interplay of DNMT1 and EZH2, and the mutual regulations among Stat3, EZH2 and DNMT1 contribute to the overall responses of β-elemene. This study uncovers a novel mechanism by which β-elemene inhibits growth of NPC cells.

Activation of AMPKα mediates additive effects of solamargine and metformin on suppressing MUC1 expression in castration-resistant prostate cancer cells

Prostate cancer is the second most common cause of cancer-related deaths worldwide. The mucin 1 (MUC1) oncoprotein is highly expressed in human prostate cancers with aggressive features. However, the role for MUC1 in occurrence and progression of castration-resistant prostate cancer (CRPC) remained elusive. In this study, we showed that solamargine, a major steroidal alkaloid glycoside, inhibited the growth of CRPC cells, which was enhanced in the presence of metformin. Furthermore, we found that solamargine increased phosphorylation of AMPKα, whereas reducing the protein expression and promoter activity of MUC1. A greater effect was observed in the presence of metformin. In addition, solamargine reduced NF-κB subunit p65 protein expression. Exogenously expressed p65 resisted solamargine-reduced MUC1 protein and promoter activity. Interestingly, exogenously expressed MUC1 attenuated solamargine-stimulated phosphorylation of AMPKα and, more importantly reversed solamargine-inhibited cell growth. Finally, solamargine increased phosphorylation of AMPKα, while inhibiting MUC1, p65 and tumor growth were observed in vivo. Overall, our results show that solamargine inhibits the growth of CRPC cells through AMPKα-mediated inhibition of p65, followed by reduction of MUC1 expression in vitro and in vivo. More importantly, metformin facilitates the antitumor effect of solamargine on CRPC cells.

Targeting EP4 downstream c-Jun through ERK1/2-mediated reduction of DNMT1 reveals novel mechanism of solamargine-inhibited growth of lung cancer cells

Lung cancer is the most common cancer and the leading cause of cancer deaths worldwide. We previously showed that solamargine, one natural phytochemicals from traditional plants, inhibited the growth of lung cancer cells through inhibition of prostaglandin E2 (PGE₂ ) receptor EP4. However, the potential downstream effectors of EP4 involving in the anti-lung cancer effects of solamargine still remained to be determined. In this study, we further verified that solamargine inhibited growth of non-small-cell lung cancer (NSCLC) cells in multiple cell lines. Mechanistically, solamargine increased phosphorylation of ERK1/2. Moreover, solamargine inhibited the protein expression of DNA methyltransferase 1 (DNMT1) and c-Jun, which were abrogated in cells treated with MEK/ERK1/2 inhibitor (PD98059) and transfected with exogenously expressed DNMT1 gene, respectively. Interestingly, overexpressed DNMT1 gene antagonized the effect of solamargine on c-Jun protein expression. Intriguingly, overexpressed c-Jun blocked solamargine-inhibited lung cancer cell growth, and feedback resisted the solamargine-induced phosphorylation of ERK1/2. A nude mouse xenograft model implanted with lung cancer cells in vivo confirmed the results in vitro. Collectively, our results show that solamargine inhibits the growth of human lung cancer cells through reduction of EP4 protein expression, followed by increasing ERK1/2 phosphorylation. This results in decrease in DNMT1 and c-Jun protein expressions. The inter-correlations between EP4, DNMT1 and c-Jun and feedback regulation of ERK1/2 by c-Jun contribute to the overall responses of solamargine in this process. This study uncovers an additional novel mechanism by which solamargine inhibits growth of human lung cancer cells.

Inactivation of PI3-K/Akt and reduction of SP1 and p65 expression increase the effect of solamargine on suppressing EP4 expression in human lung cancer cells

BACKGROUND

Lung cancer is the most common cause of cancer-related deaths worldwide. Natural phytochemicals from traditional medicinal plants such as solamargine have been shown to have anticancer properties. The prostaglandin E2 receptor EP4 is highly expressed in human cancer, however, the functional role of EP4 in the occurrence and progression of non small cell lung cancer (NSCLC) remained to be elucidated.

METHODS

Cell viability was measured by MTT assays. Western blot was performed to measure the phosphorylation and protein expression of PI3-K downstream effector Akt, transcription factors SP1, p65, and EP4. Quantitative real-time PCR (qRT-PCR) was used to examine the mRNA levels of EP4 gene. Exogenous expression of SP1, p65, and EP4 genes was carried out by transient transfection assays. EP4 promoter activity was measured by Dual Luciferase Reporter Kit.

RESULTS

We showed that solamargine inhibited the growth of lung cancer cells. Mechanistically, we found that solamargine decreased the phosphorylation of Akt, the protein, mRNA expression, and promoter activity of EP4. Moreover, solamargine inhibited protein expression of SP1 and NF-κB subunit p65, all of which were abrogated in cells transfected with exogenous expressed Akt. Intriguingly, exogenous expressed SP1 overcame the effect of solamargine on inhibition of p65 protein expression, and EP4 protein expression and promoter activity. Finally, exogenous expressed EP4 feedback reversed the effect of solamargine on phosphorylation of Akt and cell growth inhibition.

CONCLUSION

Our results show that solamargine inhibits the growth of human lung cancer cells through inactivation of Akt signaling, followed by reduction of SP1 and p65 protein expression. This results in the inhibition of EP4 gene expression. The cross-talk between SP1 and p65, and the positive feedback regulatory loop of PI3-K/Akt signaling by EP4 contribute to the overall responses of solamargine in this process. This study unveils a novel mechanism by which solamargine inhibits growth of human lung cancer cells.

Chemistry and anticarcinogenic mechanisms of glycoalkaloids produced by eggplants, potatoes, and tomatoes

Inhibition of cancer can occur via apoptosis, a genetically directed process of cell self-destruction that involves numerous biomarkers and signaling pathways. Glycoalkaloids are nitrogen-containing secondary plant metabolites found in numerous Solanaceous plants including eggplants, potatoes, and tomatoes. Exposure of cancer cells to glycoalkaloids produced by eggplants (α-solamargine and α-solasonine), potatoes (α-chaconine and α-solanine), and tomatoes (α-tomatine) or their hydrolysis products (mono-, di-, and trisaccharide derivatives and the aglycones solasodine, solanidine, and tomatidine) inhibits the growth of the cells in culture (in vitro) as well as tumor growth in vivo. This overview comprehensively surveys and consolidates worldwide efforts to define the following aspects of these natural compounds: (a) their prevalence in the three foods; (b) their chemistry and structure-activity relationships; (c) the reported factors (biomarkers, signaling pathways) associated with apoptosis of bone, breast, cervical, colon, gastric, glioblastoma, leukemia, liver, lung, lymphoma, melanoma, pancreas, prostate, and squamous cell carcinoma cell lines in vitro and the in vivo inhibition of tumor formation and growth in fish and mice and in human skin cancers; and (d) future research needs. The described results may make it possible to better relate the structures of the active compounds to their health-promoting function, individually, in combination, and in food, and allow the consumer to select glycoalkaloid-containing food with the optimal content of nontoxic beneficial compounds. The described findings are expected to be a valuable record and resource for further investigation of the health benefits of food-related natural compounds.