The effect of purple rice (Oryza sativa L. indica) extract on the inflammatory response in a colon cancer cell line and dextran sulfate-induced tumor promotion in the rat colon

The nutritional profile and human health benefit of pigmented rice and the impact of post-harvest processes and product development on the nutritional components: A review

Pigmented rice has attracted considerable attention due to its nutritional value, which is in large conferred by its abundant content of phenolic compounds, considerable micronutrient concentrations, as well as its higher resistant starch and thereby slower digestibility properties. A wide range of phenolic compounds identified in pigmented rice exhibit biological activities such as antioxidant activity, anti-inflammatory, anticancer, and antidiabetic properties. Post-harvest processes significantly reduce the levels of these phytochemicals, but recent developments in processing methods have allowed greater retention of their contents. Pigmented rice has also been converted to different products for food preservation and to derive functional foods. Profiling a large set of pigmented rice cultivars will thus not only provide new insights into the phytochemical diversity of rice and the genes underlying the vast array of secondary metabolites present in this species but also provide information concerning their nutritional benefits, which will be instrumental in breeding healthier rice. The present review mainly focuses on the nutritional composition of pigmented rice and how it can impact human health alongside the effects of post-harvest processes and product development methods to retain the ambient level of phytochemicals in the final processed form in which it is consumed.

Attenuation of benign prostatic hyperplasia by hydrophilic active compounds from pigmented rice in a testosterone implanted rat model

Benign prostatic hyperplasia (BPH) is a common chronic disease in aging men. The present study aimed to identify the active fraction of a purple rice extract and determine its anti-prostatic hyperplasia effect in a testosterone implanted rat model. The hexane insoluble fraction (HIF) which mainly contains hydrophilic phytochemicals from the purple rice crude ethanolic extract was defined as the active fraction, due to a potent effect on the downregulation of androgen receptor (AR) expression in malignant prostate cells, in addition to low toxicity for normal fibroblast cells. To induce BPH, subcutaneous implanting of a testosterone containing tube was performed in the castrated rats. Oral administration of HIF of at least 0.1 g kg-1 retarded prostate enlargement and improved histological changes induced by testosterone, without any effects on the serum testosterone levels. A lower proliferating cell nuclear antigen (PCNA) labelling index and the downregulated expression of AR, cyclinD1, and fatty acid synthase were clearly observed in the prostates of HIF-fed rats. Additionally, the mRNA levels of inflammation-related cytokines and enzymes in the prostate tissues significantly decreased after HIF treatment. Taken together, these findings demonstrate molecular mechanisms underlying the potential protective effects of the purple rice active fraction against testosterone-induced BPH in rats.

Inhibitory effect of a gamma-oryzanol-rich fraction from purple rice extract on lipopolysaccharide-induced metastasis in human colon cancer cells

The incidence of colon cancer recurrence and metastasis is known to increase as an adverse effect related to postoperative infection. Lipopolysaccharide or LPS, which is derived from gram-negative bacteria, is a key inducer of inflammatory-related tumor metastasis. Although there are numerous known biological effects of purple rice extract (PRE), its protective effect on colon metastasis was unknown. This study first evaluated the effects of hexane soluble fraction (HSF) or γ-oryzanol-rich fraction of PRE on LPS-induced colon cancer adhesion and invasion, which was accomplished using adhesive and invasive assay. Gelatin zymography was also utilized for gelatinase activity and secretion. Its chelating activity was also further analyzed by reverse gelatin zymography with zinc chloride. The study findings support the synergistic effect of HSF in protection against adverse events from LPS-induced colon cancer metastasis, as shown by effects on adhesive and invasive ability as well as matrix metalloproteinase-2 secretion and activity. PRACTICAL APPLICATIONS: Bacterial infection is still one of the main adverse events following abdominal cancer surgery and is associated with an increased incidence of colon cancer metastasis. Lipopolysaccharide (LPS) is a major component of this pathogen-mediated response. This first study investigated the efficiency of a gamma-oryzanol (OR) rich fraction, collected from purple rice extract (PRE), against LPS-induced colon cancer metastasis that occurs via three main steps; adhesion to the extracellular matrix, the secretion, and activity of gelatinase and further tissue invasion. The acquired data supported the role of an OR-rich fraction from PRE as a potential inhibitor to LPS-induced colon cancer progression. This finding, related to PRE, could be further developed to create a new adjunctive treatment to reduce operative complications related to bowel cancer surgery as well as increasing the value of this crop in Thailand.

Enhancement of Radiosensitivity by Eurycomalactone in Human NSCLC Cells Through G₂/M Cell Cycle Arrest and Delayed DNA Double-Strand Break Repair

Radiotherapy (RT) is an important treatment for non-small cell lung cancer (NSCLC). However, the major obstacles to successful RT include the low radiosensitivity of cancer cells and the restricted radiation dose, which is given without damaging normal tissues. Therefore, the sensitizer that increases RT efficacy without dose escalation will be beneficial for NSCLC treatment. Eurycomalactone (ECL), an active quassinoid isolated from Eurycoma longifolia Jack, has been demonstrated to possess anticancer activity. In this study, we aimed to investigate the effect of ECL on sensitizing NSCLC cells to X-radiation (X-ray) as well as the underlying mechanisms. The results showed that ECL exhibited selective cytotoxicity against the NSCLC cells A549 and COR-L23 compared to the normal lung fibroblast. Clonogenic survival results indicated that ECL treatment prior to irradiation synergistically decreased the A549 and COR-L23 colony number. ECL treatment reduced the expression of cyclin B1 and CDK1/2 leading to induce cell cycle arrest at the radiosensitive G₂/M phase. Moreover, ECL markedly delayed the repair of radiation-induced DNA double-strand breaks (DSBs). In A549 cells, pretreatment with ECL not only delayed the resolving of radiation-induced γ-H2AX foci but also blocked the formation of 53BP1 foci at the DSB sites. In addition, ECL pretreatment attenuated the expression of DNA repair proteins Ku-80 and KDM4D in both NSCLC cells. Consequently, these effects led to an increase in apoptosis in irradiated cells. Thus, ECL radiosensitized the NSCLC cells to X-ray via G₂/M arrest induction and delayed the repair of X-ray-induced DSBs. This study offers a great potential for ECL as an alternative safer radiosensitizer for increasing the RT efficiency against NSCLC.

Apoptosis and G2/M cell cycle arrest induced by a timosaponin A3 from Anemarrhena asphodeloides Bunge on AsPC-1 pancreatic cancer cells

BACKGROUND

Timosaponin A3 (TA3), one of the active components of spirostanol saponin isolated from A. asphodeloides, is widely used as an anticancer agent in a variety of cancer cell lines. However, the research on the anticancer efficacy is very limited in human pancreatic cancer models.

PURPOSE

In this study, we investigated the molecular targets in the active components of A. asphodeloides, which showed anti-cancer effects in human pancreatic cancer cells, and confirmed the pathways involved.

STUDY DESIGN

The apoptotic effects of five solvent extracts of A. asphodeloides in human pancreatic cancer cells (AsPC-1) was studied, and the phytochemical leading to their effects identified. Next, we determined whether the phytochemical inhibit STAT3 and ERK1/2, and investigated the pathways involved.

METHODS

Five solvent extracts of A. asphodeloides (100  µg/ml, 24  h) was investigated for their cytotoxicity against AsPC-1 cells. The active ingredient of the extract exhibiting the highest toxicity were analyzed by liquid chromatography-mass spectrometry. Next, we studied the mechanism of action of the phytochemical in pancreatic cancer. Cell cycle and annexin V/FITC assays were performed to assess cell growth and apoptosis capacity. The effects on apoptosis and proliferation-related pathways, STAT3, and MAPKs were confirmed at the protein level using immunoblotting. The factors regulated in the pathways were investigated using reverse transcription polymerase chain reaction.

RESULTS

The results showed that the ethyl acetate extract of A. asphodeloides (EAA) induced apoptotic and anti-proliferative activities through the STAT3 and MAPKs pathways. We found that TA3, an active component of EAA, inhibits constitutive STAT3 and ERK1/2 proteins. EAA and TA3 decreased the viability of AsPC-1 cells, leading to cell cycle arrest at the sub-G1 and G2/M phases. Moreover, TA3 inhibited the expression of various genes encoding anti-apoptotic (Bcl-2, Bcl-xl), proliferative (Cyclin D1), metastatic (MMP-9), and angiogenic (VEGF-1) proteins.

CONCLUSION

The results indicated that TA3, an active phytochemical from A. asphodeloides, could induce apoptosis and suppress cell proliferation by inhibiting the STAT3 and ERK1/2 pathways. Thus, TA3 is a candidate cancer chemotherapeutic agent instead to treat human pancreatic cancer.

Cucurbitacin B Induces Hypoglycemic Effect in Diabetic Mice by Regulation of AMP-Activated Protein Kinase Alpha and Glucagon-Like Peptide-1 via Bitter Taste Receptor Signaling

Taste receptors exist in several organs from tongue to colon and have diverse functions dependent on specific cell type. In enteroendocrine L-cells, stimulation of taste receptor signaling induces incretin hormones. Among incretin hormones, glucagon-like peptide-1 (GLP-1) induces insulinotropic action by activating GLP-1 receptor of pancreatic β-cells. However, GLP-1 mimetic medicines have reported clinical side effects, such as autoimmune hepatitis, acute kidney injury, pancreatitis, and pancreatic cancer. Here, we hypothesized that if natural components in ethnomedicines can activate agonistic action of taste receptor; they may stimulate GLP-1 and therefore, could be developed as safe and applicable medicines to type 2 diabetes mellitus (T2DM) with minimal side effects. Cucurbitacin B (CuB) is composed of triterpenoid structure and its structural character, that represents bitterness, can stimulate AMP-activated protein kinase (AMPK) pathway. CuB ameliorated hyperglycemia by activating intestinal AMPK levels and by inducing plasma GLP-1 and insulin release in diabetic mice. This hypoglycemic action was decreased in dorsomorphin-injected mice and α-gustducin null mice. Moreover, systemic inhibition study in differentiated NCI-H716 cell line showed that CuB-mediated GLP-1 secretion was involved in activation of AMPK through α-gustducin and Gβγ-signaling of taste receptors. In summary, we conclude that, CuB represents novel hypoglycemic agents by activation of AMPK and stimulation of GLP-1 in differentiated enteroendocrine L-cells. These results suggest that taste receptor signaling-based therapeutic agents within tremendously diverse ethnomedicines, could be applied to developing therapeutics for T2DM patients.