Inhibition of P-glycoprotein activity by limonin and other secondary metabolites from Citrus species in human colon and leukaemia cell lines

Intestinal absorption mechanism and nutritional synergy promotion strategy of dietary flavonoids: transintestinal epithelial pathway mediated by intestinal transport proteins

Dietary flavonoids exhibit a variety of physiological functions in regulating glucose and lipid metabolism, improving cardiovascular function, and enhancing stress resistance. However, poor intestinal absorption limits their health benefits. Previous studies on improving the absorption efficiency of flavonoids have focused on targeted release, enhanced gastrointestinal stability and prolonged retention time in digestive tract. But less attention has been paid to promoting the uptake and transport of flavonoids by intestinal epithelial cells through modulation of transporter protein-mediated pathways. Interestingly, some dietary nutrients have been found to modulate the expression or function of transporter proteins, thereby synergistically or antagonistically affecting flavonoid absorption. Therefore, this paper proposed an innovative regulatory strategy known as the "intestinal transport protein-mediated pathway" to promote intestinal absorption of dietary flavonoids. The flavonoid absorption mechanism in the intestinal epithelium, mediated by intestinal transport proteins, was summarized. The functional differences between the uptake transporter and efflux transporters during flavonoid trans-intestinal cellular transport were discussed. Finally, from the perspective of nutritional synergy promotion of absorption, the feasibility of promoting flavonoid intestinal absorption by regulating the expression/function of transport proteins through dietary nutrients was emphasized. This review provides a new perspective and developing precise dietary nutrient combinations for efficient dietary flavonoid absorption.

Limonin inhibits the stemness of cancer stem-like cells derived from colorectal carcinoma cells potentially via blocking STAT3 signaling

BACKGROUND

Limonin is one of the most abundant active ingredients of Tetradium ruticarpum. It exerts antitumor effects on several kinds of cancer cells. However, whether limonin exerts antitumor effects on colorectal cancer (CRC) cells and cancer stem-like cells (CSCs), a subpopulation responsible for a poor prognosis, is unclear.

AIM

To evaluate the effects of limonin on CSCs derived from CRC cells.

METHODS

CSCs were collected by culturing CRC cells in serum-free medium. The cytotoxicity of limonin against CSCs and parental cells (PCs) was determined by cholecystokinin octapeptide-8 assay. The effects of limonin on stemness were detected by measuring stemness hallmarks and sphere formation ability.

RESULTS

As expected, limonin exerted inhibitory effects on CRC cell behaviors, including cell proliferation, migration, invasion, colony formation and tumor formation in soft agar. A relatively low concentration of limonin decreased the expression stemness hallmarks, including Nanog and β-catenin, the proportion of aldehyde dehydrogenase 1-positive CSCs, and the sphere formation rate, indicating that limonin inhibits stemness without presenting cytotoxicity. Additionally, limonin treatment inhibited invasion and tumor formation in soft agar and in nude mice. Moreover, limonin treatment significantly inhibited the phosphorylation of STAT3 at Y705 but not S727 and did not affect total STAT3 expression. Inhibition of Nanog and β-catenin expression and sphere formation by limonin was obviously reversed by pretreatment with 2 μmol/L colievlin.

CONCLUSION

Taken together, these results indicate that limonin is a promising compound that targets CSCs and could be used to combat CRC recurrence and metastasis.

Bioactive Compounds from Kinnow Processing Waste and their Associated Benefits: A Review

We have explored the expansive possibilities of kinnow peel, a frequently ignored by-product of the fruit processing industry, in this thorough analysis. The production of kinnow generates a significant amount of waste, including peel, seeds, and pulp. The disposal of this waste is a major environmental issue, as it can lead to pollution and greenhouse gas emissions. Due to the presence of bioactive substances that may be used in a variety of sectors, kinnow processing waste has the potential to provide a number of advantages. In the culinary, pharmaceutical, and cosmetic industries, the peel, seeds, and pulp from kinnow can be used as natural sources of antioxidants, aromatics, pectin, and dietary fibre. Utilizing kinnow waste promotes eco-innovation, increases sustainability, and aids in waste reduction. The development of a circular economy can be sped up with more study and commercialization of kinnow waste products. This analysis emphasises how important it is to understand and utilise the unrealized potential of agricultural byproducts, like kinnow peel.

Cymbopogon citratus and Citral Overcome Doxorubicin Resistance in Cancer Cells via Modulating the Drug's Metabolism, Toxicity, and Multidrug Transporters

Multidrug resistance (MDR) is the major complex mechanism that causes the failure of chemotherapy, especially with drugs of natural origin such as doxorubicin (DOX). Intracellular drug accumulation and detoxification are also involved in cancer resistance by reducing the susceptibility of cancer cells to death. This research aims to identify the volatile composition of Cymbopogon citratus (lemon grass; LG) essential oil and compare the ability of LG and its major compound, citral, to modulate MDR in resistant cell lines. The composition of LG essential oil was identified using gas chromatography mass spectrometry (GC-MS). In addition, a comparison of the modulatory effects of LG and citral, performed on breast (MCF-7/ADR), hepatic (HepG-2/ADR), and ovarian (SKOV-3/ADR) MDR cell lines, were compared to their parent sensitive cells using the MTT assay, ABC transporter function assays, and RT-PCR. Oxygenated monoterpenes (53.69%), sesquiterpene hydrocarbons (19.19%), and oxygenated sesquiterpenes (13.79%) made up the yield of LG essential oil. α-citral (18.50%), β-citral (10.15%), geranyl acetate (9.65%), ylangene (5.70), δ-elemene (5.38%), and eugenol (4.77) represent the major constituents of LG oil. LG and citral (20 μg/mL) synergistically increased DOX cytotoxicity and lowered DOX dosage by >3-fold and >1.5-fold, respectively. These combinations showed synergism in the isobologram and CI < 1. DOX accumulation or reversal experiment confirmed that LG and citral modulated the efflux pump function. Both substances significantly increased DOX accumulation in resistant cells compared to untreated cells and verapamil (the positive control). RT-PCR confirmed that LG and citral targeted metabolic molecules in resistant cells and significantly downregulated PXR, CYP3A4, GST, MDR1, MRP1, and PCRP genes. Our results suggest a novel dietary and therapeutic strategy combining LG and citral with DOX to overcome multidrug resistance in cancer cells. However, these results should be confirmed by additional animal experiments before being used in human clinical trials.

Natural Inhibitors of P-glycoprotein in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) remains an insidious neoplasm due to the percentage of patients who develop resistance to both classic chemotherapy and emerging drugs. Multidrug resistance (MDR) is a complex process determined by multiple mechanisms, and it is often caused by the overexpression of efflux pumps, the most important of which is P-glycoprotein (P-gp). This mini-review aims to examine the advantages of using natural substances as P-gp inhibitors, focusing on four molecules: phytol, curcumin, lupeol, and heptacosane, and their mechanism of action in AML.

Limonin, a Component of Immature Citrus Fruits, Activates Anagen Signaling in Dermal Papilla Cells

Hair loss remains a significant problem that is difficult to treat; therefore, there is a need to identify safe natural materials that can help patients with hair loss. We evaluated the hair anagen activation effects of limonin, which is abundant in immature citrus fruits. Limonin increased the proliferation of rat dermal papilla cells (rDPC) by changing the levels of cyclin D1 and p27, and increasing the number of BrdU-positive cells. Limonin increased autophagy by decreasing phosphorylated mammalian target of rapamycin levels and increasing the phospho-Raptor, ATG7 and LC3B. Limonin also activated the Wnt/β-catenin pathway by increasing phospho-β-catenin levels. XAV939, a Wnt/β-catenin inhibitor, inhibited these limonin-induced changes, including induced autophagy, BrdU-positive cells, and cell proliferation. Limonin increased the phosphorylated AKT levels in both two-dimensional cultured rDPC and three-dimensional spheroids. Treatment with the PI3K inhibitor wortmannin inhibited limonin-induced proliferation, and disrupted other limonin-mediated changes, including decreased p27, increased BrdU-positive cells, induced autophagy, and increased ATG7 and LC3B levels. Wortmannin also inhibited limonin-induced cyclin D1 and LC3 expression in spheroids. Collectively, these results indicate that limonin can enhance anagen signaling by activating autophagy via targeting the Wnt/β-catenin and/or PI3K/AKT pathways in rDPC, highlighting a candidate nutrient for hair loss treatment.

Recent advances in the biosynthesis, bioavailability, toxicology, pharmacology, and controlled release of citrus neohesperidin

Neohesperidin (hesperetin 7-O-neohesperidoside), a well-known flavanone glycoside widely found in citrus fruits, exhibits a variety of biological activities, with potential applications ranging from food ingredients to therapeutics. The purpose of this manuscript is to provide a comprehensive overview of the chemical, biosynthesis, and pharmacokinetics profiles of neohesperidin, as well as the therapeutic effects and mechanisms of neohesperidin against potential diseases. This literature review covers a wide range of pharmacological responses elicited by Neohesperidin, including neuroprotective, anti-inflammatory, antidiabetic, antimicrobial, and anticancer activities, with a focus on the mechanisms of those pharmacological responses. Additionally, the mechanistic pathways underlying the compound's osteoporosis, antiulcer, cardioprotective, and hepatoprotective effects have been outlined. This review includes detailed illustrations of the biosynthesis, biopharmacokinetics, toxicology, and controlled release of neohesperidine. Neohesperidin demonstrated a broad range of therapeutic and biological activities in the treatment of a variety of complex disorders, including neurodegenerative, hepato-cardiac, cancer, diabetes, obesity, infectious, allergic, and inflammatory diseases. Neohesperidin is a promising therapeutic candidate for the management of various etiologically complex diseases. However, further in vivo and in vitro studies on mechanistic potential are required before clinical trials to confirm the safety, bioavailability, and toxicity profiles of neohesperidin.

Potential of Kalanchoe pinnata as a Cancer Treatment Adjuvant and an Epigenetic Regulator

Cancer is a global public health problem that is related to different environmental and lifestyle factors. Although the combination of screening, prevention, and treatment of cancer has resulted in increased patient survival, conventional treatments sometimes have therapeutic limitations such as resistance to drugs or severe side effects. Oriental culture includes herbal medicine as a complementary therapy in combination with chemotherapy or radiotherapy. This study aimed to identify the bioactive ingredients in Kalanchoe pinnata, a succulent herb with ethnomedical applications for several diseases, including cancer, and reveal its anticancer mechanisms through a molecular approach. The herb contains gallic acid, caffeic acid, coumaric acid, quercetin, quercitrin, isorhamnetin, kaempferol, bersaldegenin, bryophyllin a, bryophyllin c, bryophynol, bryophyllol and bryophollone, stigmasterol, campesterol, and other elements. Its phytochemicals participate in the regulation of proliferation, apoptosis, cell migration, angiogenesis, metastasis, oxidative stress, and autophagy. They have the potential to act as epigenetic drugs by reverting the acquired epigenetic changes associated with tumor resistance to therapy-such as the promoter methylation of suppressor genes, inhibition of DNMT1 and DNMT3b activity, and HDAC regulation-through methylation, thereby regulating the expression of genes involved in the PI3K/Akt/mTOR, Nrf2/Keap1, MEK/ERK, and Wnt/β-catenin pathways. All of the data support the use of K. pinnata as an adjuvant in cancer treatment.

Bioavailability of Hesperidin and Its Aglycone Hesperetin—Compounds Found in Citrus Fruits as a Parameter Conditioning the Pro-Health Potential (Neuroprotective and Antidiabetic Activity)—Mini-Review

Hesperidin and hesperetin are polyphenols that can be found predominantly in citrus fruits. They possess a variety of pharmacological properties such as neuroprotective and antidiabetic activity. However, the bioavailability of these compounds is limited due to low solubility and restricts their use as pro-healthy agents. This paper described the limitations resulting from the low bioavailability of the presented compounds and gathered the methods aiming at its improvement. Moreover, this work reviewed studies providing pieces of evidence for neuroprotective and antidiabetic properties of hesperidin and hesperetin as well as providing a detailed look into the significance of reported modes of action in chronic diseases. On account of a well-documented pro-healthy activity, it is important to look for ways to overcome the problem of poor bioavailability.

Current Advances in Coptidis Rhizoma for Gastrointestinal and Other Cancers

Cancer is a serious disease with an increasing number of reported cases and high mortality worldwide. Gastrointestinal cancer defines a group of cancers in the digestive system, e.g., liver cancer, colorectal cancer, and gastric cancer. Coptidis Rhizoma (C. Rhizoma; Huanglian, in Chinese) is a classical Chinese medicinal botanical drug for the treatment of gastrointestinal disorders and has been shown to have a wide variety of pharmacological activity, including antifungal, antivirus, anticancer, antidiabetic, hypoglycemic, and cardioprotective effects. Recent studies on C. Rhizoma present significant progress on its anticancer effects and the corresponding mechanisms as well as its clinical applications. Herein, keywords related to C. Rhizoma, cancer, gastrointestinal cancer, and omics were searched in PubMed and the Web of Science databases, and more than three hundred recent publications were reviewed and discussed. C. Rhizoma extract along with its main components, berberine, palmatine, coptisine, magnoflorine, jatrorrhizine, epiberberine, oxyepiberberine, oxyberberine, dihydroberberine, columbamine, limonin, and derivatives, are reviewed. We describe novel and classic anticancer mechanisms from various perspectives of pharmacology, pharmaceutical chemistry, and pharmaceutics. Researchers have transformed the chemical structures and drug delivery systems of these components to obtain better efficacy and bioavailability of C. Rhizoma. Furthermore, C. Rhizoma in combination with other drugs and their clinical application are also summarized. Taken together, C. Rhizoma has broad prospects as a potential adjuvant candidate against cancers, making it reasonable to conduct additional preclinical studies and clinical trials in gastrointestinal cancer in the future.

Nanoplatform-based natural products co-delivery system to surmount cancer multidrug-resistant

The emergence of multidrug resistance (MDR) in malignant tumors is the primary reason for invalid chemotherapy. Antitumor drugs are often adversely affected by the MDR of tumor cells. Treatments using conventional drugs, which have specific drug targets, hardly regulate the complex signaling pathway of MDR cells because of the complex formation mechanism of MDR. However, natural products have positive advantages, such as high efficiency, low toxicity, and ability to target multiple mechanism pathways associated with MDR. Natural products, as MDR reversal agents, synergize with chemotherapeutics and enhance the sensitivity of tumor cells to chemotherapeutics, and the co-delivery of natural products and antitumor drugs with nanocarriers maximizes the synergistic effects against MDR in tumor cells. This review summarizes the molecular mechanisms of MDR, the advantages of natural products combined with chemotherapeutics in offsetting complicated MDR mechanisms, and the types and mechanisms of natural products that are potential MDR reversal modulators. Meanwhile, aiming at the low bioavailability of cocktail combined natural products and chemotherapeutic in vivo, the advantages of nanoplatform-based co-delivery system and recent research developments are illustrated on the basis of our previous research. Finally, prospective horizons are analyzed, which are expected to considerably improve the nano-co-delivery of natural products and chemotherapeutic systems for MDR reversal in cancer.

Multiple Molecular Mechanisms to Overcome Multidrug Resistance in Cancer by Natural Secondary Metabolites

Plant secondary metabolites (SMs) common natural occurrences and the significantly lower toxicities of many SM have led to the approaching development and use of these compounds as effective pharmaceutical agents; especially in cancer therapy. A combination of two or three of plant secondary metabolites together or of one SM with specific anticancer drugs, may synergistically decrease the doses needed, widen the chemotherapeutic window, mediate more effective cell growth inhibition, and avoid the side effects of high drug concentrations. In mixtures they can exert additive or even synergistic activities. Many SM can effectively increase the sensitivity of cancer cells to chemotherapy. In phytotherapy, secondary metabolites (SM) of medicinal plants can interact with single or multiple targets. The multi-molecular mechanisms of plant secondary metabolites to overcome multidrug resistance (MDR) are highlighted in this review. These mechanisms include interaction with membrane proteins such as P-glycoprotein (P-gp/MDR1); an ATP-binding cassette (ABC) transporter, nucleic acids (DNA, RNA), and induction of apoptosis. P-gp plays an important role in the development of MDR in cancer cells and is involved in potential chemotherapy failure. Therefore, the ingestion of dietary supplements, food or beverages containing secondary metabolites e.g., polyphenols or terpenoids may alter the bioavailability, therapeutic efficacy and safety of the drugs that are P-gp substrates.

Tangeretin boosts the anticancer activity of metformin in breast cancer cells via curbing the energy production

BACKGROUND

Breast cancer is the first leading cause of women cancer-related deaths worldwide. While there are many proposed treatments for breast cancer, low efficacy, toxicity, and resistance are still major therapeutic obstacles. Thus, there is a need for safer and more effective therapeutic approaches. Because of the direct link between obesity and carcinogenesis, energy restriction mimetic agents (ERMAs) such as the antidiabetic agent, metformin was proposed as a novel antiproliferative agent. However, the anticancer dose of metformin alone is relatively high and impractical to be implemented safely in patients. The current work aimed to sensitize resistant breast cancer cells to metformin's antiproliferative effect using the natural potential anticancer agent, tangeretin.

METHODS

The possible synergistic combination between metformin and tangeretin was initially evaluated using MTT cell viability assay in different breast cancer cell lines (MCF-7, MDA-MB-231, and their resistant phenotype). The possible mechanisms of synergy were investigated via Western blotting analysis, reactive oxygen species (ROS) measurement, annexin/PI assay, cell cycle analysis, and wound healing assay.

RESULTS

The results indicated the ability of tangeretin to improve the anticancer activity of metformin. Interestingly, the improved activity was almost equally observed in both parental and resistant cancer cells, which underlines the importance of this combination in cases of the emergence of resistance. The synergy was mediated through the enhanced activation of AMPK and ROS generation in addition to the improved inhibition of cell migration, induction of cell cycle arrest, and apoptosis in cancer cells.

CONCLUSION

The current work underscores the importance of metformin as an ERMA in tackling breast cancer and as a novel approach to boost its anticancer activity via a synergistic combination with tangeretin.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Synthesis of some tropane-based compounds targeting colon cancer

Background: In continuation of a previous work concerned with the anticancer activity of some 8-alkyl-2,4-bisarylidene-8-nortropan-3-ones, this work focuses on further modification to the tropane/pyran fused skeleton aiming to obtain improved anticancer activity. Methodology: Reaction of 8-alkyl-2,4-bisarylidene-8-nortropan-3-ones 1-21 with malononitrile under basic conditions afforded tropane/pyran hybrids 22-40 and tropane/pyridine hybrids 41, 42. X-ray crystallography for compounds 22 and 41 as representative examples confirmed their structures. They were tested for their anticancer activity in the HCT116 cell line. Results: Compounds 26 and 33 were the most active compounds with IC₅₀ values of 3.39 and 0.01 μM against HCT116. Moreover, they revealed cyclin-dependent kinase-2 (CDK2) inhibition with IC₅₀ = 104.91 and 49.13 nM, respectively. Furthermore, molecular docking of compounds 26 and 33 in the active site of CDK2 confirmed the obtained results. Conclusion: Tropane/pyran scaffold can be considered as a promising core for anticancer agents acting as CDK2 inhibitors.

Limonin ameliorates dextran sulfate sodium-induced chronic colitis in mice by inhibiting PERK-ATF4-CHOP pathway of ER stress and NF-κB signaling

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammation regulated by intricate mechanisms. Limonin, a natural tetracyclic triterpenoid compound, possesses multiple bioactivities including anti-inflammation, anti-cancer and so on. However, the therapeutic potential and the underlying mechanism of limonin on IBD remain unclear. Here, we probe into the effect of limonin on chronic colitis induced by dextran sulfate sodium (DSS) and illustrated the potential mechanisms. We found that limonin relieved the risk and severity of DSS-induced chronic colitis in mice through various aspects including increasing body weight and colon length, decreasing the mortality rate, inhibiting MPO activity and improving colon pathology. Limonin also decreased the production of proinflammatory cytokines TNF-α, IL-1β, IL-6 and the expression of inflammatory proteins COX-2, iNOS in colon tissues from DSS-induced colitis mice. Moreover, limonin attenuated DSS-induced chronic colitis by inhibiting PERK-ATF4-CHOP pathway of endoplasmic reticulum (ER) stress and NF-κB signaling. In vitro, limonin not only decreased LPS-induced higher production of pro-inflammatory cytokines and inflammatory proteins mentioned above by inhibiting NF-κB signaling in macrophage cells RAW264.7, but also suppressed PERK-ATF4-CHOP pathway of ER stress. In summary, our study demonstrated that limonin mitigated DSS-induced chronic colitis via inhibiting PERK-ATF4-CHOP pathway of ER stress and NF-κB signaling. All of this study provides the possibility for limonin as an effective drug for chronic colitis of IBD in the future.

The carotenoid fucoxanthin can sensitize multidrug resistant cancer cells to doxorubicin via induction of apoptosis, inhibition of multidrug resistance proteins and metabolic enzymes

BACKGROUND

Multidrug resistance (MDR) causes failure of doxorubicin therapy of cancer cells, which develops after or during doxorubicin treatment resulting in cross-resistance to structurally and functionally-unrelated other anticancer drugs. MDR is multifactorial phenomenon associated with overexpression of ATP-binding cassette (ABC) transporters, metabolic enzymes, impairment of apoptosis, and alteration of cell cycle checkpoints. The cancer-prevention of the dietary carotenoid; fucoxanthin (FUC) has been extensively explored. Nevertheless, the underlying mechanism of its action is not full elucidated.

HYPOTHESIS/PURPOSE

Investigation of the underlying mechanism of MDR reversal by the dietary carotenoid fucoxanthin (FUC) and its ability to enhance the doxorubicin (DOX) cytotoxicity in resistant breast (MCF-7/ADR), hepatic (HepG-2/ADR), and ovarian (SKOV-3/ADR) cell lines.

METHODS

The synergistic interaction of FUC and DOX was evaluated using several techniques, viz.; MTT assay, ABC transporter function assays using FACS and fluorimetry, enzyme activity via spectroscopy and luminescence assays, and apoptosis assay using FACS, and gene expression using RTPCR.

RESULTS

FUC (20 µM) synergistically enhanced the cytotoxicity of DOX and significantly reduced the dose of DOX (FR) in DOX resistant cells (MCF-7/ADR), hepatic (HepG-2/ADR), and ovarian (SKOV-3/ADR) to 8.42-(CI= 0.25), 6.28-(CI= 0.32), and 4.56-fold (CI=0.37) (P<0.001). FUC significantly increased the accumulation of DOX more than verapamil in resistant cells by 2.70, 2.67, and 3.95-fold of untreated cells (p<0.001), respectively. A FUC and DOX combination significantly increased the Rho123 accumulation higher than individual drugs by 2.36-, 2.38-, 1.89-fold verapamil effects in tested cells (p<0.001), respectively. The combination of the FUC and DOX decreased ABCC1, ABCG2, and ABCB1 expression. The FUC and DOX combination increased the levels and activity of caspases (CASP3, CASP8) and p53, while decreased the levels and activity of CYP3A4, GST, and PXR in resistant cancer cells. The combination induced early/late apoptosis to 91.9/5.4% compared with 0.0/0.7% of untreated control.

CONCLUSION

Our data suggests a new dietary and therapeutic approach of combining the FUC with DOX to overcome multidrug resistance in cancer cells. However, animal experiments should be conducted to confirm the findings before applying the results into clinical trials.

Impact of kinnow peel and nano-limonin on the performance and meat quality of commercial broilers

This study was taken up with the objective to assess the effect of limonin on the performance of commercial broilers and quality of meat. Day old chicks (200) were divided into 8 groups, each group contained 4 replicates of 6 chicks each in equal sex ratio. The iso-nitrogenous and iso-caloric diets were fed for 35 days, i.e. starter, grower and finisher phase. Kinnow peel powder (KPP) and solid lipid nanoparticles (SLN) of kinnow peel powder containing 7.47 mg limonin/g was added in the required quantity of feed to supply 0, 0.5, 1.0 and 1.5 mg limonin/bird/day. The data was analyzed using 2×4 factorial design. The data revealed that the birds fed diet supplemented with SLN consumed more feed in comparison to those fed diet supplemented with KPP, resulting in higher gain in weight, but without affecting feed conversion ratio (FCR). The digestibility of CP was lower and that of CF was higher when diet was supplemented with SLN in comparison to the one supplemented with KPP. As compared to control diet, limonin up to 1% level did not have any adverse effect on the digestibility of nutrients, but it was depressed beyond 1% level of limonin supplementation. The limonin beyond 1% depressed the dressing percentage. It was concluded that nano-formulations @ 1.0 mg/bird/d is an effective carrier of limonins, leading to improved growth, health characteristics in broilers and meat enriched with limonin.

Phytochemicals: Potential Lead Molecules for MDR Reversal

Multidrug resistance (MDR) is one of the main impediments in the treatment of cancers. MDR cancer cells are resistant to multiple anticancer drugs. One of the major mechanisms of MDR is the efflux of anticancer drugs by ABC transporters. Increased activity and overexpression of these transporters are important causes of drug efflux and, therefore, resistance to cancer chemotherapy. Overcoming MDR is a fundamental prerequisite for developing an efficient treatment of cancer. To date, various types of ABC transporter inhibitors have been employed but no effective anticancer drug is available at present, which can completely overcome MDR. Phytochemicals can reverse MDR in cancer cells via affecting the expression or activity of ABC transporters, and also through exerting synergistic interactions with anticancer drugs by addressing additional molecular targets. We have listed numerous phytochemicals which can affect the expression and activity of ABC transporters in MDR cancer cell lines. Phytochemicals in the groups of flavonoids, alkaloids, terpenes, carotenoids, stilbenoids, lignans, polyketides, and curcuminoids have been examined for MDR-reversing activity. The use of MDR-reversing phytochemicals with low toxicity to human in combination with effective anticancer agents may result in successful treatment of chemotherapy-resistant cancer. In this review, we summarize and discuss published evidence for natural products with MDR modulation abilities.

The MYB transcription factor CiMYB42 regulates limonoids biosynthesis in citrus

BACKGROUND

Limonoids are major bioactive compounds that are produced by the triterpenoid metabolic pathway. The detailed biochemical process of limonoid biosynthesis and the mechanism of its molecular regulation remain elusive. The identification of transcription factors that regulate limonoid biosynthetic pathways is very important for understanding the underlying regulatory mechanisms. This information could also provide tools for manipulating biosynthesis genes to modulate limonoid production.

RESULTS

In this study, the CiMYB42 transcription factor was isolated to identify its role in limonoid biosynthesis. Multiple alignment analysis and phylogenetic analysis demonstrated that CiMYB42 is a typical R2R3MYB transcription factor that shares high similarity of its amino acid sequence with AtMYB42. Limonoids contents were higher in Citrus sinensis and Citrus grandis than in other species. Limonoid accumulation during leaf development also showed diverse trends in different genotypes. The expression of CiMYB42 was significantly related to the limonoid content and the expression of CiOSC in some citrus accessions. The overexpression of CiMYB42 in sweet orange resulted in significant accumulation of limonin, whereas the downregulation of CiMYB42 by RNAi resulted in a dwarf phenotype and less nomilin accumulation. Furthermore, the results of a yeast one-hybrid assay and EMSA indicated that CiMYB42 binds exclusively to the TTGTTG sequence (type II MYB core) in the promoter of CiOSC. Together, these results suggest that CiMYB42 positively regulates limonoid biosynthesis by regulating the expression of CiOSC by binding to the TTGTTG sequence (type II MYB core) of its promoter.

CONCLUSIONS

CiMYB42 is an important transcription activator involved in limonoid biosynthesis that regulates the expression of CiOSC by binding to the TTGTTG sequence (type II MYB core).

Limonin suppresses the progression of oral tongue squamous cell carcinoma via inhibiting YAP transcriptional regulatory activity

The suppressive roles of limonin have been established in various tumors. However, its roles in oral tongue squamous cell carcinoma (OTSCC) progression are still confusing. This work aims to explore limonin-mediated effects on OTSCC progression. CCK8 analysis was performed to evaluate limonin-mediated effects on OTSCC cell viability. Wound healing and transwell invasion analysis were constructed to examine the effects of limonin on OTSCC cell migration and invasion capacity. RT-qPCR, western blot and luciferase reporter assays were used to explore the underlying mechanisms contributing to limonin-mediated effects on OTSCC progression. It was found that limonin significantly suppressed the viability of OTSCC cells. Additionally, limonin reduced the migration and invasion ability of OTSCC cells. Mechanistically, limonin suppresses OTSCC progression by promoting the nuclear to cytoplasm translocation of YAP, decreasing YAP protein expression and subsequently decreasing YAP transcriptional regulatory activity, this is responsible for limonin-mediated suppression on OTSCC progression. Thus, this work suggests that limonin suppresses OTSCC progression through inhibiting YAP transcriptional regulatory activity.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

Ohmic heating polyphenolic extracts from vine pruning residue with enhanced biological activity

Vine Pruning residue was submitted to conventional heating and ohmic heating (OH) for the extraction of bioactive compounds and analyzed for total phenolic content (TPC), polyphenolic profile, antioxidant activity, antimicrobial activity and anticancer activity. The OH extracts were obtained using Low electric field (496.0 V/cm) or Intermediate electric field - IEF (840.0 V/cm). The tests were performed using 45% (v/v) ethanol-water extraction solution at 80 °C at different extraction times (20-90 min). The extract that stood out among the others concerning anticancer potential was the one obtained by OH when used, IEF, where the TPC was significantly higher than in the other extracts which correlated with higher antioxidant, antimicrobial and anti-proliferative activity on different tumor cell lines (HepG2, MDA-MB-231, MCF-7 and Caco2). Vine pruning OH extracts obtained using green solvents by an eco-friendly procedure were revealed as a source of compounds with relevant antioxidant and anticancer activity.

Alleviation of Multidrug Resistance by Flavonoid and Non-Flavonoid Compounds in Breast, Lung, Colorectal and Prostate Cancer

The aim of the manuscript is to discuss the influence of plant polyphenols in overcoming multidrug resistance in four types of solid cancers (breast, colorectal, lung and prostate cancer). Effective treatment requires the use of multiple toxic chemotherapeutic drugs with different properties and targets. However, a major cause of cancer treatment failure and metastasis is the development of multidrug resistance. Potential mechanisms of multidrug resistance include increase of drug efflux, drug inactivation, detoxification mechanisms, modification of drug target, inhibition of cell death, involvement of cancer stem cells, dysregulation of miRNAs activity, epigenetic variations, imbalance of DNA damage/repair processes, tumor heterogeneity, tumor microenvironment, epithelial to mesenchymal transition and modulation of reactive oxygen species. Taking into consideration that synthetic multidrug resistance agents have failed to demonstrate significant survival benefits in patients with different types of cancer, recent research have focused on beneficial effects of natural compounds. Several phenolic compounds (flavones, phenolcarboxylic acids, ellagitannins, stilbens, lignans, curcumin, etc.) act as chemopreventive agents due to their antioxidant capacity, inhibition of proliferation, survival, angiogenesis, and metastasis, modulation of immune and inflammatory responses or inactivation of pro-carcinogens. Moreover, preclinical and clinical studies revealed that these compounds prevent multidrug resistance in cancer by modulating different pathways. Additional research is needed regarding the role of phenolic compounds in the prevention of multidrug resistance in different types of cancer.

Anticancer effect of Limonin against benzo(a)pyrene-induced lung carcinogenesis in Swiss albino mice and the inhibition of A549 cell proliferation through apoptotic pathway

The main purpose of the current study is to reveal the anticancer action of limonin against benzo(a)pyrene [B(a)P]-treated lung carcinogenesis in Swiss albino mice and A549 lung cancer cells. B(a)P was orally supplemented (50 mg/kg body weight) twice a week for four weeks induction of lung cancer in mice. The lung weight, body weight, incidence of tumor, lipid peroxidation, carcinoembryonic antigen (CEA), enzymatic and nonenzymatic antioxidants (superoxide dismutase, GPx, glutathione, glutathione reductase, catalase, and glutathione S-transferase), serum marker enzymes (aryl hydroxylase, lactate dehydrogenase, 5'-nucleotidases, and γ-glutamyl transpeptidase), and inflammatory mediators (interleukin-1β, interleukin-6, and tumor necrosis factor-α) were estimated. Moreover, a histopathological study of lung tissues was supported by the biochemical analysis. Furthermore, the anticancer activity of limonin on A549 cells was measured by cell viability, production of reactive oxygen species (ROS), apoptotic morphological changes by AO/EtBr staining. Additionally, the status of apoptosis protein (caspase-9 and -3) expressions was analyzed by the colorimetric analysis. B(a)P-induced mice showed increased lipid peroxidation, CEA, serum marker enzymes and inflammatory cytokines levels with simultaneously decreased in the nonenzymatic and enzymatic antioxidants levels. Limonin supplements significantly reverted back to all these changes in this manner, showing the efficiency of anticancer effect. Furthermore, our in vitro study also supported the anticancer effect of the treatment of limonin-enhanced apoptosis by loss of cell viability, improved ROS production, apoptotic morphological changes, and apoptosis protein expression were analyzed. Overall, these results suggest the anticancer potential of limonin against B(a)P-induced lung cancer in Swiss albino mice and A549 lung cancer cells.

Anti-inflammatory and cytotoxic activities of the extracts, fractions, and chemical constituents isolated from Luehea ochrophylla Mart

BACKGROUND

Stem bark of Luehea ochrophylla (L. ochrophylla) is used by the traditional Brazilian medicine for treatment of rheumatic diseases and tumors. This study aimed to investigate inhibition of acute and chronic inflammations and cytotoxic activity of extracts, fractions, and isolated compounds from L. ochrophylla.

METHODS

Hexane (HE) and ethanol (EE) extracts obtained from stem bark of L. ochrophylla were submitted to chromatographic fractionation. In order to test acute inflammation, experimental model of impact injury was used, followed by transdermal application of gels using phonophoresis. Histological analysis was based on scores assigned by the capacity of decreasing the lesion. To evaluate the effect EE and fractions on cell proliferation, human lymphocytes were stimulated with phytohemagglutinin and analyzed using flow cytometry. Proliferation was measured using VPD 450 staining and the calculated proliferative index (PI). The cytotoxic activity was evaluated using MTT colorimetric method against MDA-MB-231, MCF-7, HCT-116, and Vero cells. GraphPad Prism Version 5 was used for statistical analysis.

RESULTS

HE and EE provided friedelin, β-friedelinol, lupeol, mixture of lupeol and pseudotaraxasterol, β-sitosterol, betulinic acid, mixture of lupeol and taraxasterol, (-)-epicatechin, β-sitosterol-3-O-β-D-glucopyranoside, and (+)-epicatechin-(4β-8)-epicatechin. HE, ethyl acetate fraction (AF), betulinic acid, and β-sitosterol promoted regeneration of muscle fibers caused by muscle injury. AF significantly (p < 0.05) reduced the lymphocyte proliferation index (1.36 for cultures stimulated with PHA, 0.7 for untreated cultures and 0.12 for cultures stimulated with PHA and treated with AF 25 μg/mL and AF 50 μg/mL, respectively). β-Sitosterol-3-O-β-D-glucopyranoside exhibited high cytotoxic activity (IC50 = 1.279 μg/mL) against HCT-116 cell line.

CONCLUSION

These results suggest that extracts, fractions, and chemical constituents from L. ochrophylla decreases inflammatory processes generated by muscle injury. The anti-inflammatory activity may be justified by high inhibition of T cell proliferation. These extracts, fractions, and chemical constituents from L. ochrophylla may be useful as a therapeutic agent against rheumatic diseases. Moreover, chemical constituents from L. ochrophylla show potent cytotoxic activity against colon and rectal carcinomas.

Limonin: A Review of Its Pharmacology, Toxicity, and Pharmacokinetics

Limonin is a natural tetracyclic triterpenoid compound, which widely exists in Euodia rutaecarpa (Juss.) Benth., Phellodendron chinense Schneid., and Coptis chinensis Franch. Its extensive pharmacological effects have attracted considerable attention in recent years. However, there is no systematic review focusing on the pharmacology, toxicity, and pharmacokinetics of limonin. Therefore, this review aimed to provide the latest information on the pharmacology, toxicity, and pharmacokinetics of limonin, exploring the therapeutic potential of this compound and looking for ways to improve efficacy and bioavailability. Limonin has a wide spectrum of pharmacological effects, including anti-cancer, anti-inflammatory and analgesic, anti-bacterial and anti-virus, anti-oxidation, liver protection properties. However, limonin has also been shown to lead to hepatotoxicity, renal toxicity, and genetic damage. Moreover, limonin also has complex impacts on hepatic metabolic enzyme. Pharmacokinetic studies have demonstrated that limonin has poor bioavailability, and the reduction, hydrolysis, and methylation are the main metabolic pathways of limonin. We also found that the position and group of the substituents of limonin are key in affecting pharmacological activity and bioavailability. However, some issues still exist, such as the mechanism of antioxidant activity of limonin not being clear. In addition, there are few studies on the toxicity mechanism of limonin, and the effects of limonin concentration on pharmacological effects and toxicity are not clear, and no researchers have reported any ways in which to reduce the toxicity of limonin. Therefore, future research directions include the mechanism of antioxidant activity of limonin, how the concentration of limonin affects pharmacological effects and toxicity, finding ways to reduce the toxicity of limonin, and structural modification of limonin—one of the key methods necessary to enhance pharmacological activity and bioavailability.

Limonin enhances the radiosensitivity of nasopharyngeal carcinoma cells via attenuating Stat3-induced cell stemness

The inhibitory effects of limonin have been disclosed in various tumors, however, its roles in nasopharyngeal carcinoma (NPC) progression are never been revealed. In the current work, we collected NPC cells with a higher stemness compared with bulk cells through isolating the side population (SP) cells. It was found that limonin exhibited a stronger inhibitory effect on SP cells than that in bulk cells, which was evident by a lower IC50 value. Additionally, limonin attenuated the stemness and migration ability of SP cells with the higher stemness, characterized as decreasing the spheroid formation ability, expression of stemness markers and migration ability. Moreover, the proportion of SP cells in G0 phase was remarkably higher than that in bulk cells. Notably, upon limonin treatment, the proportion of SP cells in G0 was decreased and S/G2/M increased. Furthermore, limonin enhanced the radiosensitivity of NPC cells. The mechanistic studies based on RNA-sequencing analysis revealed that limonin inhibited the gene transcription driven by Stat3 (signal transducer and activator of transcription 3) and an activator of Stat3 (Colivelin or IL-6) rescued the inhibitory effects of limonin. Therefore, these results demonstrate that limonin could reduce the stemness of NPC cells and thus the radiosensitivity through suppressing Stat3 transcriptional activity.

Natural products as multidrug resistance modulators in cancer

Cancer is a prominent cause of death globally. Currently, many drugs that are in clinical practice are having a high prevalence of side effect and multidrug resistance. Risk of tumors acquiring resistance to chemotherapy (multidrug resistance) remains a significant hurdle to the successful treatment of various types of cancer. Membrane-embedded drug transporters, generally overexpressed in cancer, are the leading cause among multiple mechanisms of multidrug resistance (MDR). P-glycoprotein (P-gp) also MDR1/ABCB1, multidrug resistance associated protein 1 (MRP1/ABCC1), MRP2 and breast cancer resistance protein (BCRP/ABCG2) are considered to be a prime factor for induction of MDR. To date, several chemical substances have been tested in a number of clinical trials for their MDR modulatory activity which are not having devoid of any side effects that necessitates to find newer and safer way to tackle the current problem of multidrug resistance in cancer. The present study systematically discusses the various classes of natural products i.e flavonoids, alkaloids, terpenoids, coumarins (from plants, marine, and microorganisms) as potential MDR modulators and/or as a source of promising lead compounds. Recently a bisbenzyl isoquinoline alkaloid namely tetrandrine, isolated from Chinese herb Stephania tetrandra (Han-Fang-Chi) is in clinical trials for its MDR reversal activity.

Synthesis, antiproliferative activity and 2D-QSAR study of some 8-alkyl-2,4-bisbenzylidene-3-nortropinones

AIM

Colon cancer is the third leading cause of death worldwide; therefore, there is a need for an effective therapy with lower side effects.

METHODS

A series of 8-alkyl-2,4-bisbenzylidene-3-nortropinones 3 & 14-39 was prepared via Claisen-Schmidt condensation of 8-alkyl-3-nortropinones 11-13 with different aromatic aldehydes. The target compounds were screened for their antiproliferative activity.

RESULTS

Most of the prepared compounds showed promising antiproliferative activity against many of 60 National Cancer Institute cell lines at 10 μM. Furthermore, 8-ethyl-2,4-bis(3,4-dimethoxybenzylidene)-8-nortropin-3-one 29 and its 3,4,5-trimethoxy analog 30 were the most active compounds against HCT116 cell line with IC₅₀ values 0.01 and 0.46 μM, respectively. Using CODESSA-Pro software, a significant 2D-quantitative structure-activity relationship (QSAR) model was obtained.

CONCLUSION

The 8-Alkyl-2,4-bisbenzylidene-8-azabicyclo[3.2.1]octan-3-one represents an interesting core for further structural optimization to obtain more promising hits.

Citron Essential Oils Alleviate the Mediators Related to Rosacea Pathophysiology in Epidermal Keratinocytes

Background

Citron is well known for an abundance of antioxidative and anti-inflammatory ingredients such as vitamin C, polyphenol compounds, flavonoids, and limonoids.

Objective

In this study, we aimed to evaluate the effects of citron essential oils on rosacea mediators in activated keratinocytes in vitro.

Methods

Normal human epidermal keratinocytes (NHEKs) were stimulated with 1α, 25-dihydroxyvitamin D₃ (VD₃) and interleukin 33 (IL-33) with LL-37 to induce rosacea mediators such as kallikrein 5 (KLK5), cathelicidin, vascular endothelial growth factor (VEGF), and transient receptor potential vanilloid 1 (TRPV1). These mediators were analyzed by performing reverse-transcription polymerase chain reaction (PCR), quantitative real-time PCR, immunocytofluorescence and enzyme-linked immunosorbent assay after NHEKs were treated with citron seed and unripe citron essential oils.

Results

The messenger RNA (mRNA) and protein levels of KLK5 and LL-37 induced by VD₃ were suppressed by citron seed and unripe citron essential oils. Furthermore, the mRNA and protein levels of VEGF and TRPV1 induced by IL-33 with LL-37 were also suppressed by citron essential oils.

Conclusion

These results show that citron essential oils have suppressive effects on rosacea mediators in activated epidermal keratinocytes, which indicates that the citron essential oils may be valuable adjuvant therapeutic agents for rosacea.

Variation in limonin and nomilin content in citrus fruits of eight varieties determined by modified HPLC

The nomilin and limonin content in citrus fruits of different varieties was determined at fruit growth and maturation stages by HPLC. The results showed that the two limonoids can be separated, identified, and quantified in citrus fruits within 10 min by the developed method. The method exhibited good precision, repeatability, stability, and recovery rate. The content of limonin and nomilin in most citrus fruits presented an increasing trend initially, and then decreased during fruit growth and maturation; a peak was observed at the young fruit or fruit expansion stage. The dropped fruits also contained some amount of limonoids, suggesting their industrial application. The variation and cluster analyses results revealed that the orange varieties contained the highest amount of limonoids at the mature stage. The results of this study will enable better use of citrus limonoids.

7-Isopenthenyloxycoumarin, Arctigenin, and Hesperidin Modify Myeloid Cell Leukemia Type-1 (Mcl-1) Gene Expression by Hormesis in K562 Cell Line

Hormesis is a new concept in dose–response relationship. Despite of traditional dose–response curves, there is a low-dose stimulation and a high-dose inhibition in this case. Hormesis effect in apoptosis induction/inhibition by natural compounds is reported previously. Here, we searched this effect for myeloid cell leukemia type-1 (Mcl-1) gene expression by phytochemicals 7-isopenthenyloxycoumarin (7-IP), arctigenin (Arg), and hesperidin (Hsp). For this purpose, first we tested the cytotoxicity of various doses of these compounds against K562 leukemia cell lines for different times by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. After that we explored the effect of various doses of these phytochemicals on Mcl-1 gene expression for different times by real-time polymerase chain reaction method. We found that these phytochemicals have cytotoxicity against K562 cell line. Hesperidin is the most cytotoxic agent. We also found that these natural compounds have hormetic effect on Mcl-1 gene expression. The hormetic model in Mcl-1 gene expression is overcompensation stimulation. This phenomenon is reported for the first time. We conclude that 7-IP, Arg, and Hsp are cytotoxic against K562 cancerous cells and induce/inhibit Mcl-1 gene expression by hormesis dose–response relationship.

Hexane fraction of adlay (Coix lachryma-jobi L.) testa ethanolic extract inhibits human uterine sarcoma cancer cells growth and chemosensitizes human uterine sarcoma cells to doxorubicin

BACKGROUND

Cancer has remained among the top ten causes of death in Taiwan since 1982. Uterine sarcoma is a rare gynecologic cancer, and chemotherapy is one type of cancer treatment. Doxorubicin (Dox) is widely used for treating several cancers, including uterine sarcoma, however, multidrug resistance (MDR) is a major clinical problem and a critical cause of treatment failure. The ethanolic extracts of adlay testa (ATE) exhibited significant anticancer activities against many cancer types.

PURPOSE

In this study we investigated the antitumor effects of the hexane fraction of the adlay testa ethanolic extracts (ATE-Hex) on the human uterine sarcoma cancer cell line MES-SA, as well as on the multidrug-resistant human uterine sarcoma cancer cell line MES-SA/Dx5.

METHODS

The MTT assay was performed to assess the effects of the extracts of different parts of the adlay on the proliferation of human uterine sarcoma cells (MES-SA and MES-SA/Dx5) and human uterine smooth muscle cells (HUtSMCs). To determine whether ATE-Hex has a chemosensitizing effect on drug-resistant uterine sarcoma cells, the MTT assay was performed to examine the synergistic effects of ATE-Hex, the chemotherapeutic drug Dox alone, and in combination. Rhodamine accumulation was analyzed using fluorescence detection. Apoptotic cells were analyzed via flow cytometry. In addition, employing a flame ionization detector (GC/FID) gas chromatography was also developed as the analysis platform for ATE-Hex.

RESULTS

The results demonstrated that ATE-Hex exhibited the best effects of inhibition on MES-SA and MES-SA/Dx5 cells. Co-treatment of ATE-Hex and Dox could synergistically inhibit the proliferation of cancer cells. ATE-Hex reduced the rhodamine efflux in MES-SA/Dx5 cells, indicating that ATE-Hex could reduce the expression of P-gp. In addition, our results showed that treatment with ATE-Hex alone or in combination with Dox significantly inhibited the growth of cancer cells and induced apoptosis by increasing the sub-G1 phase and poly(ADP-ribose) polymerase (PARP) being cleaved. Flow cytometry revealed that ATE-Hex induced apoptosis.

CONCLUSION

These results suggest that ATE-Hex can inhibit human uterine sarcoma cancer cells by inducing apoptosis and increasing the chemosensitivity of the multidrug-resistant human uterine sarcoma cancer cell MES-SA/Dx5 to Dox. Furthermore, the combination of ATE-Hex and Dox could decrease MDR and increase the synergistic effect.

Solamargine, a bioactive steroidal alkaloid isolated from Solanum aculeastrum induces non-selective cytotoxicity and P-glycoprotein inhibition

Background

Solanum aculeastrum fruits are used by some cancer sufferers as a form of alternative treatment. Scientific literature is scarce concerning its anticancer activity, and thus the aim of the study was to assess the in vitro anticancer and P-glycoprotein inhibitory potential of extracts of S. aculeastrum fruits. Furthermore, assessment of the combinational effect with doxorubicin was also done.

Methods

The crude extract was prepared by ultrasonic maceration. Liquid-liquid extraction yielded one aqueous and two organic fractions. Bioactive constituents were isolated from the aqueous fraction by means of column chromatography, solid phase extraction and preparative thin-layer chromatography. Confirmation of bioactive constituent identity was done by nuclear magnetic resonance and ultra-performance liquid chromatography mass spectrometry. The crude extract and fractions were assessed for cytotoxicity and P-glycoprotein inhibition in both cancerous and non-cancerous cell lines using the sulforhodamine B and rhodamine-123 assays, respectively.

Results

Both the crude extract and aqueous fraction was cytotoxic to all cell lines, with the SH-SY5Y neuroblastoma cell line being most susceptible to exposure (IC₅₀ = 10.72 μg/mL [crude], 17.21 μg/mL [aqueous]). Dose-dependent P-glycoprotein inhibition was observed for the crude extract (5.9 to 18.9-fold at 100 μg/mL) and aqueous fraction (2.9 to 21.2 at 100 μg/mL). The steroidal alkaloids solamargine and solanine were identified. While solanine was not bioactive, solamargine displayed an IC₅₀ of 15.62 μg/mL, and 9.1-fold P-glycoprotein inhibition at 100 μg/mL against the SH-SY5Y cell line. Additive effects were noted for combinations of doxorubicin against the SH-SY5Y cell line.

Conclusions

The crude extract and aqueous fraction displayed potent non-selective cytotoxicity and noteworthy P-glycoprotein inhibition. These effects were attributed to solamargine. P-glycoprotein inhibitory activity was only present at concentrations higher than those inducing cytotoxicity, and thus does not appear to be the likely mechanism for the enhancement of doxorubicin’s cytotoxicity. Preliminary results suggest that non-selective cytotoxicity may hinder drug development, however, further assessment of the mode of cell death is necessary to determine the route forward.

A significant mechanism of molecular recognition between bioflavonoids and P-glycoprotein leading to herb-drug interactions

Inhibition of P-glycoprotein (P-gp)'s function may conduct significant changes in the prescription drugs' pharmacokinetic profiles and escalate potential risks in taking place of drug/herb-drug interactions. Computational modeling was advanced to scrutinize some bioflavonoids which play roles in herb-drug interactions as P-gp inhibitors utilizing molecular docking and pharmacophore analyses. Twenty-five flavonoids were utilized as ligands for the modeling. The mouse P-gp (code: 4Q9H) was acquired from the PDB. The docking was operated utilizing AutoDock version 4.2.6 (Scripps Research Institute, La Jolla, CA) against the NBD2 of 4Q9H. The result illustrated the high correlation between the docking scores and observed activities of the flavonoids and the putative binding site of these flavonoids was proposed and compared with the site for ATP. To evaluate hotspot amino acid residues within the NBD2, Binding modes for the ligands were achieved using LigandScout to originate the NBD2-flavonoid pharmacophore models. The results asserted that these inhibitors competed with ATP for binding site in the NBD2 (as competitive inhibitors) including the hotspot residues which associated with electrostatic and van der Waals interactions with the flavonoids. In MD simulation of eight delegated complexes selected from the analyzed flavonoid subclasses, RMSD analysis of the trajectories indicated the residues were stable throughout the duration of simulations.

Natural Products as Alternative Choices for P-Glycoprotein (P-gp) Inhibition

Multidrug resistance (MDR) is regarded as one of the bottlenecks of successful clinical treatment for numerous chemotherapeutic agents. Multiple key regulators are alleged to be responsible for MDR and making the treatment regimens ineffective. In this review, we discuss MDR in relation to P-glycoprotein (P-gp) and its down-regulation by natural bioactive molecules. P-gp, a unique ATP-dependent membrane transport protein, is one of those key regulators which are present in the lining of the colon, endothelial cells of the blood brain barrier (BBB), bile duct, adrenal gland, kidney tubules, small intestine, pancreatic ducts and in many other tissues like heart, lungs, spleen, skeletal muscles, etc. Due to its diverse tissue distribution, P-gp is a novel protective barrier to stop the intake of xenobiotics into the human body. Over-expression of P-gp leads to decreased intracellular accretion of many chemotherapeutic agents thus assisting in the development of MDR. Eventually, the effectiveness of these drugs is decreased. P-gp inhibitors act by altering intracellular ATP levels which are the source of energy and/or by affecting membrane contours to increase permeability. However, the use of synthetic inhibitors is known to cause serious toxicities. For this reason, the search for more potent and less toxic P-gp inhibitors of natural origin is underway. The present review aims to recapitulate the research findings on bioactive constituents of natural origin with P-gp inhibition characteristics. Natural bioactive constituents with P-gp modulating effects offer great potential for semi-synthetic modification to produce new scaffolds which could serve as valuable investigative tools to recognize the function of complex ABC transporters apart from evading the systemic toxicities shown by synthetic counterparts. Despite the many published scientific findings encompassing P-gp inhibitors, however, this article stand alones because it provides a vivid picture to the readers pertaining to Pgp inhibitors obtained from natural sources coupled with their mode of action and structures. It provides first-hand information to the scientists working in the field of drug discovery to further synthesise and discover new P-gp inhibitors with less toxicity and more efficacies.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions

The most commonly prescribed oral anticoagulants worldwide are the vitamin K antagonists (VKAs) such as warfarin. Factors affecting the pharmacokinetics of VKAs are important because deviations from their narrow therapeutic window can result in bleedings due to over-anticoagulation or thrombosis because of under-anticoagulation. In addition to pharmacodynamic interactions (e.g., augmented bleeding risk for concomitant use of NSAIDs), interactions with drugs, foods, herbs, and over-the-counter medications may affect the risk/benefit ratio of VKAs. Direct oral anticoagulants (DOACs) including Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and thrombin inhibitor (dabigatran) are poised to replace warfarin. Phase-3 studies and real-world evaluations have established that the safety profile of DOACs is superior to those of VKAs. However, some pharmacokinetic and pharmacodynamic interactions are expected. Herein we present a critical review of VKAs and DOACs with focus on their potential for interactions with drugs, foods, herbs and over-the-counter medications.

The Chemistry and Pharmacology of Citrus Limonoids

Citrus limonoids (CLs) are a group of highly oxygenated terpenoid secondary metabolites found mostly in the seeds, fruits and peel tissues of citrus fruits such as lemons, limes, oranges, pumellos, grapefruits, bergamots, and mandarins. Represented by limonin, the aglycones and glycosides of CLs have shown to display numerous pharmacological activities including anticancer, antimicrobial, antioxidant, antidiabetic and insecticidal among others. In this review, the chemistry and pharmacology of CLs are systematically scrutinised through the use of medicinal chemistry tools and structure-activity relationship approach. Synthetic derivatives and other structurally-related limonoids from other sources are include in the analysis. With the focus on literature in the past decade, the chemical classification of CLs, their physico-chemical properties as drugs, their biosynthesis and enzymatic modifications, possible ways of enhancing their biological activities through structural modifications, their ligand efficiency metrics and systematic graphical radar plot analysis to assess their developability as drugs are among those discussed in detail.

Chemopreventive Agents and Inhibitors of Cancer Hallmarks: May Citrus Offer New Perspectives?

Fruits and vegetables have long been recognized as potentially important in the prevention of cancer risk. Thus, scientific interest in nutrition and cancer has grown over time, as shown by increasing number of experimental studies about the relationship between diet and cancer development. This review attempts to provide an insight into the anti-cancer effects of Citrus fruits, with a focus on their bioactive compounds, elucidating the main cellular and molecular mechanisms through which they may protect against cancer. Scientific literature was selected for this review with the aim of collecting the relevant experimental evidence for the anti-cancer effects of Citrus fruits and their flavonoids. The findings discussed in this review strongly support their potential as anti-cancer agents, and may represent a scientific basis to develop nutraceuticals, food supplements, or complementary and alternative drugs in a context of a multi-target pharmacological strategy in the oncology.

3D-QSAR modelling dataset of bioflavonoids for predicting the potential modulatory effect on P-glycoprotein activity

The data is obtained from exploring the modulatory activities of bioflavonoids on P-glycoprotein function by ligand-based approaches. Multivariate Linear-QSAR models for predicting the induced/inhibitory activities of the flavonoids were created. Molecular descriptors were initially used as independent variables and a dependent variable was expressed as pFAR. The variables were then used in MLR analysis by stepwise regression calculation to build the linear QSAR data. The entire dataset consisted of 23 bioflavonoids was used as a training set. Regarding the obtained MLR QSAR model, R of 0.963, R²=0.927, Radj2=0.900, SEE=0.197, F=33.849 and q²=0.927 were achieved. The true predictabilities of QSAR model were justified by evaluation with the external dataset (Table 4). The pFARs of representative flavonoids were predicted by MLR QSAR modelling. The data showed that internal and external validations may generate the same conclusion.

Dose-response relationship in Schistosoma mansoni juvenile and adult stages following limonin treatment in experimentally infected mice

Preventive chemotherapy with praziquantel is the mainstay of schistosomiasis control. However, drug resistance is an imminent threat, particularly with large-scale administration of praziquantel, in addition to much less efficacy against young schistosomes. Several biological activities of limonin have been explored such as insecticidal, insect antifeedant, and growth-regulating activity on insects as well as antimalarial, antiviral, anticancer, cholesterol-lowering, and antioxidant activities. This study investigates limonin as an alternative antischistosomal compound using two novel, single, oral dose regimens. In the current work, the therapeutic efficacy of different limonin dosing protocols was evaluated in experimentally infected mice harboring Schistosoma mansoni (Egyptian strain) juvenile or adult stages. Oral administration of limonin in a single dose of 50 or 100 mg/kg on day 21 post-infection (p.i.) resulted in a significant worm burden reduction of 70.0 and 83.33 %, respectively. The same dose given on day 56 p.i. reduced total worm burdens by 41.09 and 60.27 %, respectively. In addition, significant reductions of 34.90 and 47.16 % in the hepatic and 46.67 and 56.1 % in the intestinal tissue egg loads, respectively, associated with significant alterations in the oogram pattern with elevated dead egg levels. Limonin produced ameliorations of hepatic pathology with reduction in dimensions and number of granulomas. Limonin also produced a variety of tegumental alterations in treated worms including tubercular disruption, edema, blebbing, and ulcerations. Results obtained by this work elucidated promising limonin bioactivity against S. mansoni juvenile and adult stages and provided a basis for subsequent experimental and clinical trials.

P-glycoprotein Mediated Efflux Modulators of Plant Origin: A Short Review

Drug efflux transporters such as P-glycoprotein (P-gp) help maintain cellular homeostasis but are also major contributors to the development of multidrug resistance (MDR) phenomena. Since P-gp was associated with MDR, several compounds showing potential to inhibit this transporter have been identified. Particular attention has been given to natural products, namely those of plant origin, looking for highly effective and safe P-gp inhibitors with little to no interaction with other cellular or metabolic processes. Here we abridge several examples of plant compounds from distinct classes, polyketides, lignans, anthraquinones, coumarins, alkaloids, mono- and sesqui-terpenes, steroids and limonoids, which have shown the ability to modulate in vitro or in vivo the P-gp activity.