Apoptosis-mediated proliferation inhibition of human colon cancer cells by volatile principles of Citrus aurantifolia

A recent update on the connection between dietary phytochemicals and skin cancer: emerging understanding of the molecular mechanism

Constant exposure to harmful substances from both inside and outside the body can mess up the body's natural ways of keeping itself in balance. This can cause severe skin damage, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. However, plant-derived compounds found in fruits and vegetables have been shown to protect against skin cancer-causing free radicals and other harmful substances. It has been determined that these dietary phytochemicals are effective in preventing skin cancer and are widely available, inexpensive, and well-tolerated. Studies have shown that these phytochemicals possess anti-inflammatory, antioxidant, and antiangiogenic properties that can aid in the prevention of skin cancers. In addition, they influence crucial cellular processes such as angiogenesis and cell cycle control, which can halt the progression of skin cancer. The present paper discusses the benefits of specific dietary phytochemicals found in fruits and vegetables, as well as the signaling pathways they regulate, the molecular mechanisms involved in the prevention of skin cancer, and their drawbacks.

Phytochemical Profile of Cymbopogon citratus (DC.) Stapf Lemongrass Essential Oil from Northeastern Thailand and Its Antioxidant and Antimicrobial Attributes and Cytotoxic Effects on HT-29 Human Colorectal Adenocarcinoma Cells

Colorectal cancer is the third most prevalent cancer in Thailand, prompting the search for alternative or preventive treatments using natural constituents. In this study, the authors employed hydrodistillation to extract Cymbopogon citratus (DC.) Stapf (lemongrass) essential oil (LEO) from plants in northeastern Thailand and assessed its chemical profile, antioxidant, antimicrobial, and anticancer properties. The LEO displayed potent antioxidant activities in DPPH and hydroxyl scavenging assays with IC50 values of 2.58 ± 0.08 and 4.05 ± 0.12 mg/mL, respectively, and demonstrated antimicrobial activities against Escherichia coli, Cutibacterium acnes, Streptococcus agalactiae, and Staphylococcus aureus at 8-10 µg/mL. At 48 h, the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay showed the LEO exhibiting low cell viability (3%) at concentrations of 200-400 µg/mL, with an IC50 value of 82.46 ± 1.73 µg/mL, while in the clonogenic assay it exhibited a lower IC50 value of 23.11 ± 1.80 µg/mL. The GC-MS analysis identified citral (79.24%) consisting of 44.52% geranial and 34.72% neral, and β-myrcene (5.56%). The addition of LEO significantly influenced apoptotic genes (Bcl-2, Bax, p21, and Caspase-3) and proteins, as indicated by real-time polymerase chain reaction (RT-PCR) and Western blot studies. Results suggested that LEO initiated apoptosis through intrinsic pathways and demonstrated potential as a chemopreventive, antimicrobial, and antioxidant agent with substantial health advantages.

Citrus Essential Oils: A Rational View on its Chemical Profiles, Mode of Action of Anticancer Effects/Antiproliferative Activity on Various Human Cancer Cell Lines

Cancer is a complex genetic disorder due to uncontrolled growth of abnormal cells in the body, causes damage to the immune system, and may lead to life-threatening situations. Common approaches to cancer treatment includes chemotherapy, hormone therapy, immunotherapy, radiation therapy etc. Development of novel and natural chemotherapeutic agents is highly demanded because of the side effects of synthetic drugs. Essential oils from aromatic plants exhibited antioxidant, antimutagenic, antiproliferative and immunomodulating activities. Mechanism of multidrug resistance and synergistic action of these volatile constituents are responsible for their chemopreventive properties. These oils primarily comprising of terpenoid constituents and are characterized by volatility, aroma, low molecular weight etc. The chemical composition of these oils varies depending on the environmental condition, species, plant part and geographical region. Literature analysis revealed that plant essential oils play an important role in cancer prevention and treatment. Cancer patients exposed to essential oils via inhaler devices were found to have less anxiety, stress, and nausea and insomnia. Nowadays, there is an increasing demand for investigating the biological properties of aromatic plants due to their availability, chemical diversity, and low toxicity. In aromatherapy, Citrus essential oils repress cancer related pain and enhance immune system. Current review summarizes existing variability of the chemical composition of Citrus essential oils and its molecular level anticancer mechanism against various human cancer cell lines. Citrus essential oils enhance cytotoxicity, antiproliferative and apoptotic behavior of cancer cell lines. Since essential oils exhibiting significant anticancer potential is worthy of further investigation for cancer chemoprevention. The findings of various research activities can be exploited by cancer researchers world wide for the development of anticancer drugs which can relieve cancer symptoms.

Natural essential oils as a new therapeutic tool in colorectal cancer

Colorectal cancer (CRC) is the third most revalent type of cancer in the world and the second most common cause of cancer death (about 1 million per year). Historically, natural compounds and their structural analogues have contributed to the development of new drugs useful in the treatment of various diseases, including cancer. Essential oils are natural odorous products made up of a complex mixture of low molecular weight compounds with recognized biological and pharmacological properties investigated also for the prevention and treatment of cancer. The aim of this paper is to highlight the possible role of essential oils in CRC, their composition and the preclinical studies involving them. It has been reviewed the preclinical pharmacological studies to determine the experimental models used and the anticancer potential mechanisms of action of natural essential oils in CRC. Searches were performed in the following databases PubMed/Medline, Web of science, TRIP database, Scopus, Google Scholar using appropriate MeSH terms. The results of analyzed studies showed that EOs exhibited a wide range of bioactive effects like cytotoxicity, antiproliferative, and antimetastatic effects on cancer cells through various mechanisms of action. This updated review provides a better quality of scientific evidence for the efficacy of EOs as chemotherapeutic/chemopreventive agents in CRC. Future translational clinical studies are needed to establish the effective dose in humans as well as the most suitable route of administration for maximum bioavailability and efficacy. Given the positive anticancer results obtained from preclinical pharmacological studies, EOs can be considered efficient complementary therapies in chemotherapy in CRC.

Citrus Essential Oils in Aromatherapy: Therapeutic Effects and Mechanisms

Citrus is one of the main fruit crops cultivated in tropical and subtropical regions worldwide. Approximately half (40-47%) of the fruit mass is inedible and discarded as waste after processing, which causes pollution to the environment. Essential oils (EOs) are aromatic compounds found in significant quantities in oil sacs or oil glands present in the leaves, flowers, and fruit peels (mainly the flavedo part). Citrus EO is a complex mixture of ~400 compounds and has been found to be useful in aromatic infusions for personal health care, perfumes, pharmaceuticals, color enhancers in foods and beverages, and aromatherapy. The citrus EOs possess a pleasant scent, and impart relaxing, calming, mood-uplifting, and cheer-enhancing effects. In aromatherapy, it is applied either in message oils or in diffusion sprays for homes and vehicle sittings. The diffusion creates a fresh feeling and enhances relaxation from stress and anxiety and helps uplifting mood and boosting emotional and physical energy. This review presents a comprehensive outlook on the composition, properties, characterization, and mechanism of action of the citrus EOs in various health-related issues, with a focus on its antioxidant properties.

Anticancer activity of Nigerian medicinal plants: a review

Background

Cancer is currently the leading cause of death globally and the number of deaths from cancer is on the rise daily. Medicinal plants have been in continuous use over the years for the management of cancer, particularly, in most developing countries of the world including Nigeria. The use of synthetic drugs for the treatment of cancer is often accompanied by toxic side effects. Thus, the alternative use of readily available and inexpensive medicinal plants is the panacea to the toxic side effects associated with synthetic drugs.

Main body

The present review summarized the anticancer activity of 51 medicinal plants that are widespread in all regions of Nigeria. Furthermore, the proposed anticancer pharmacological actions as well as the anticancer bioactive compounds, the type of cancer cell inhibited, the plant parts responsible for the anticancer activity, and the nature of the extracts used for the studies were discussed in this review. The 51 Nigerian medicinal plants were reported to exhibit anticancer activities of the prostate, cervices, lung, skin, colon, esophagus, blood, ovary, central nervous system/brain, breast, stomach, pancreas, larynx, and kidney. The major classes of bioactive compounds indicated to be responsible for the anticancer activity include the polyphenols, flavonoids, alkaloids, saponins, triterpenes, tannins, and quinones. The major anticancer pharmacological actions of these bioactive compounds were antiproliferative, cytotoxic, cytostatic, antimetastatic, apoptotic, and antioxidative as well as provoked cell cycle arrest, inhibition of angiogenesis and reduction of cancer cell viability.

Conclusion

The Nigerian medicinal plants can be harnessed to provide for readily available and inexpensive anticancer drugs in the future because the plants reported in this review showed promising anticancer activity.

Insights into the chemical composition and bioactivities of citrus peel essential oils

Citrus peel (CP), a by-product of the citrus fruit processing, comprises nearly forty to fifty percent of the fruit portion. Interestingly, the essential oil (EO) is primarily concentrated in the peel portion of the citrus fruit. Extraction of CP essential oil (CPEO) is an effective way of utilizing the citrus fruit processing waste. The CPEO can be more efficiently recovered from CP waste by improving the efficiency of conventional extraction processes. The main components of CPEO include monoterpenes, sesquiterpenes and their oxygenated derivatives. Specifically, limonene is the major oil component identified in the peel of different citrus species. The health promoting biological activities of CPEO are functioning as antioxidant, anti-inflammatory, analgesic, antimicrobial and anticancer agents, thereby can be used as a source of functional components and preservatives for the development of nutritionally safe newer food products. This paper provides an in-depth knowledge about the chemical constituents and bioactivities of EOs extracted from peels of different citrus species.

Thermosensitive Betulinic Acid-Loaded Magnetoliposomes: A Promising Antitumor Potential for Highly Aggressive Human Breast Adenocarcinoma Cells Under Hyperthermic Conditions

PURPOSE

Breast cancer presents one of the highest rates of prevalence around the world. Despite this, the current breast cancer therapy is characterized by significant side effects and high risk of recurrence. The present work aimed to develop a new therapeutic strategy that may improve the current breast cancer therapy by developing a heat-sensitive liposomal nano-platform suitable to incorporate both anti-tumor betulinic acid (BA) compound and magnetic iron nanoparticles (MIONPs), in order to address both remote drug release and hyperthermia-inducing features. To address the above-mentioned biomedical purposes, the nanocarrier must possess specific features such as specific phase transition temperature, diameter below 200 nm, superparamagnetic properties and heating capacity. Moreover, the anti-tumor activity of the developed nanocarrier should significantly affect human breast adenocarcinoma cells.

METHODS

BA-loaded magnetoliposomes and corresponding controls (BA-free liposomes and liposomes containing no magnetic payload) were obtained through the thin-layer hydration method. The quality and stability of the multifunctional platforms were physico-chemically analysed by the means of RAMAN, scanning electron microscopy-EDAX, dynamic light scattering, zeta potential and DSC analysis. Besides this, the magnetic characterization of magnetoliposomes was performed in terms of superparamagnetic behaviour and heating capacity. The biological profile of the platforms and controls was screened through multiple in vitro methods, such as MTT, LDH and scratch assays, together with immunofluorescence staining. In addition, CAM assay was performed in order to assess a possible anti-angiogenic activity induced by the test samples.

RESULTS

The physico-chemical analysis revealed that BA-loaded magnetoliposomes present suitable characteristics for the purpose of this study, showing biocompatible phase transition temperature, a diameter of 198 nm, superparamagnetic features and heating capacity. In vitro results showed that hyperthermia induces enhanced anti-tumor activity when breast adenocarcinoma MDA-MB-231 cells were exposed to BA-loaded magnetoliposomes, while a low cytotoxic rate was exhibited by the non-tumorigenic breast epithelial MCF 10A cells. Moreover, the in ovo angiogenesis assay endorsed the efficacy of this multifunctional platform as a good strategy for breast cancer therapy, under hyperthermal conditions. Regarding the possible mechanism of action of this multifunctional nano-platform, the immunocytochemistry of the MCF7 and MDA-MB-231 breast carcinoma cells revealed a microtubule assembly modulatory activity, under hyperthermal conditions.

CONCLUSION

Collectively, these findings indicate that BA-loaded magnetoliposomes, under hyperthermal conditions, might serve as a promising strategy for breast adenocarcinoma treatment.

Isolation and biological activity of agrostophillinol from kaffir lime (Citrus hystrix) leaves

The leaves of the kaffir lime (Citrus hystrix) are commonly used in cuisine and folk medicine. The aim of this study was to isolate a bioactive compound in kaffir lime leaves and characterize its biological activity. The compound was isolated from a hexane fractional extract and identified as agrostophillinol. This is the first report of agrostophillinol isolated from kaffir lime leaves. In terms of cytotoxicity, agrostophillinol exhibited IC₅₀ values of 36.27 ± 7.30 and 53.44 ± 10.63 μg/mL against EoL-1 and HL60 cells, respectively. Agrostophillinol also exhibited potent anti-inflammatory activity, significantly inhibiting IL-6 secretion.

Antileukemic Cell Proliferation of Active Compounds from Kaffir Lime (Citrus hystrix) Leaves

Kaffir lime (Citrus hystrix) is a plant member of family Rutaceae, and its leaves are commonly used in folk medicine. The present study explores antileukemic effects of the extracts and purified active compounds from the leaves. The antileukemic activity was investigated via inhibition of Wilms’ tumor 1 (WT1), which is a protein that involves in leukemic cell proliferation. In addition, the compounds were investigated for their effects on WT1 gene expression using real time RT-PCR and Western blotting. Cell cycle arrest and total cell number were investigated using flow cytometry and trypan blue exclusion method, respectively. The results demonstrated that the hexane fractionated extract had the greatest inhibitory effect on WT1 gene expression of many leukemic cell lines and significantly decreased WT1 protein levels of K562 cells (representative of the leukemic cells), in a dose- and time-dependent manner. Subfraction No. 9 (F9) after partial purification of hexane fractioned extract showed the highest suppression on WT1 protein and suppressed cell cycle at G2/M. The organic compounds were isolated from F9 and identified as phytol and lupeol. The bioassays confirmed antiproliferative activities of natural products phytol and lupeol. The results demonstrated anticancer activity of the isolated phytol and lupeol to decrease leukemic cell proliferation.

β-Caryophyllene in the Essential Oil from Chrysanthemum Boreale Induces G1 Phase Cell Cycle Arrest in Human Lung Cancer Cells

Chrysanthemum boreale is a plant widespread in East Asia, used in folk medicine to treat various disorders, such as pneumonia, colitis, stomatitis, and carbuncle. Whether the essential oil from C. boreale (ECB) and its active constituents have anti-proliferative activities in lung cancer is unknown. Therefore, we investigated the cytotoxic effects of ECB in A549 and NCI-H358 human lung cancer cells. Culture of A549 and NCI-H358 cells with ECB induced apoptotic cell death, as revealed by an increase in annexin V staining. ECB treatment reduced mitochondrial membrane potential (MMP), disrupted the balance between pro-apoptotic and anti-apoptotic Bcl-2 proteins, and activated caspase-8, -9, and -3, as assessed by western blot analysis. Interestingly, pretreatment with a broad-spectrum caspase inhibitor (z-VAD-fmk) significantly attenuated ECB-induced apoptosis. Furthermore, gas chromatography-mass spectrometry (GC/MS) analysis of ECB identified six compounds. Among them, β-caryophyllene exhibited a potent anti-proliferative effect, and thus was identified as the major active compound. β- Caryophyllene induced G₁ cell cycle arrest by downregulating cyclin D1, cyclin E, cyclin-dependent protein kinase (CDK) -2, -4, and -6, and RB phosphorylation, and by upregulating p21^CIP1/WAF1 and p27^KIP1. These results indicate that β-caryophyllene exerts cytotoxic activity in lung cancer cells through induction of cell cycle arrest.

Fumonisins: Impact on Agriculture, Food, and Human Health and their Management Strategies

The fumonisins producing fungi, Fusarium spp., are ubiquitous in nature and contaminate several food matrices that pose detrimental health hazards on humans as well as on animals. This has necessitated profound research for the control and management of the toxins to guarantee better health of consumers. This review highlights the chemistry and biosynthesis process of the fumonisins, their occurrence, effect on agriculture and food, along with their associated health issues. In addition, the focus has been put on the detection and management of fumonisins to ensure safe and healthy food. The main focus of the review is to provide insights to the readers regarding their health-associated food consumption and possible outbreaks. Furthermore, the consumers' knowledge and an attempt will ensure food safety and security and the farmers' knowledge for healthy agricultural practices, processing, and management, important to reduce the mycotoxin outbreaks due to fumonisins.

Citrus peels prevent cancer

BACKGROUND

Citrus comprises the largest fruit sector worldwide, and its fruit peels are the dominant 'residue' of the industry. Though not profitable, Citrus peels are industrially used for making some byproducts (cattle feed, molasses, ethanol, fiber) and for the extraction of bioactives (flavonoids, essential oils, d-limonene). Still huge amounts of peels are wasted by Citrus industries, juice and other vending sectors.

PURPOSE

The biological potentials of these unutilized or 'wasted' Citrus peels are least exploited. Here we tested the anticancer potentials of Citrus medica (2 morphotypes), C. sinensis, C. maxima, C. limon and C. reticulata peels by in vitro assays and in vivo cancer models.

METHODS

Chemical profiles of Citrus peel oils and peel extracts were analyzed by gas chromatographic techniques (GC-FID, GC-MS) and HPTLC-densitometry, respectively. Anticancer potentials of Citrus peels (Citrus medica 2 morphotypes, C. sinensis, C. maxima, C. limon and C. reticulata) were evaluated by various in vitro assays (MTT assay, morphological observations, fast halo assay, flow cytometric analysis) and in vivo cancer models.

RESULTS

C. reticulata peels (extracts, essential oils) showed significant activity against DLA cell line in MTT assay. We found C. reticulata peel water extract inducing cell cycle arrest of DLA in G0/G1 phase followed by nuclear condensation, membrane blebbing, formation of apoptotic bodies and DNA damage leading to apoptosis. In in vivo experiments, C. reticulata peel extract pre-treated mice were significantly (50%) protected from DLA compared to post-treated mice (33%), without any conspicuous toxic symptoms. Citrus peels have volatiles (essential oils, limonoids) and non-volatiles (mainly polymethoxy flavones) as their bioactive/anticancer constituents.

CONCLUSION

Our results encourage the use of Citrus peels, which is wasted in huge amounts, as cancer preventive food additives and as anticancer agents.

Insight into the negative impact of ionic liquid: A cytotoxicity mechanism of 1-methyl-3-octylimidazolium bromide

Ionic liquids (ILs) as a green replacement for volatile organic solvents are increasingly used in large-scale commercial applications. A good understanding of the toxic mechanisms and environmental impact of ILs is neede to reduce the risk for human health and the environment. For this purpose, we aimed to evaluate the possible impacts of 1-methyl-3-octylimidazolium bromide ([C₈mim]Br) exposure on human hepatocellular carcinoma (HepG2) cells as to elucidate the cytotoxic mechanism of [C₈mim]Br. Biochemical assays revealed that [C₈mim]Br exposure altered the protein levels of heat shock protein 70 (HSP70) and HSP90, generally inhibiting total antioxidative capacity (T-AOC), depleting heme oxygenase-1 (HO-1) and increasing transcription and activity of inducible nitric oxide synthase (iNOS) in HepG2 cells. These results indicated that [C₈mim]Br may induce biochemical disturbances and cause oxidative stress in HepG2 cells. Moreover, increased phosphorylation of p53, mitochondrial membrane disruption, cyclooxygenase-2 activation, Bcl-2 family protein modulation, cytochrome c and Smac/DIABLO release, and inhibition of apoptosis inhibitory protein-2 (c-IAP2) and survivin were also observed in [C₈mim]Br-treated cells, suggesting that [C₈mim]Br-induced apoptosis might be mediated by the mitochondrial pathway. Further research showed that [C₈mim]Br exposure increased tumour necrosis factor α (TNF-α) transcription and content and promoted the expression of Fas and FasL, indicating that TNF-α and Fas/FasL are involved in the apoptosis induced by [C₈mim]Br. Additionally, [C₈mim]Br cytotoxicity was partly inhibited by N-acetyl-cysteine (NAC), and NAC reversed [C₈mim]Br-mediated mitochondrial dysfunction and blocked apoptotic events by inhibiting the generation of reactive oxygen species (ROS). This work first demonstrated that the ROS-mediated mitochondrial and death receptor-initiated apoptotic pathway is involved in [C₈mim]Br-induced HepG2 cell apoptosis.

Experimental Paper. The effect of different development stages on the quantity and quality of the essential oil of Citrus aurantifolia (Christm.) Swingle in Iran

Introduction: The Mexican lime tree with the scientific name of Citrus aurantifolia (Christm.) Swingle have great economic value because of its essential oil with a unique flavour. Objective: The essential oils from the peel of C. aurantifolia were collected during three development periods. Methods: The essential oil was analyzed by capillary GC and GC-MS. Results: The essential oil yields (v/w%) were 1.54%, 0.88% and 1.23%, respectively. The highest oil yield was obtained at stage I (1.54% v/w). The analysis of the essential oil indicated that limonene, β-pinene, geranial, neral and γ-terpinene were the main compounds of all samples. At the first stage, the highest percentages belonged to limonene (39.38%), geranial (14.32%) and neral (11.01%). On the other hand, the highest percentages of β-pinene and γ-terpinene (24.25% and 8.92%, respectively) were found at the final stage. Conclusion: Therefore, it is concluded that the harvest time has a considerable effect on the content and amount of lime fruit essential oil.

Enhanced colon cancer chemoprevention of curcumin by nanoencapsulation with whey protein

To improve bioavailability and enhance colon cancer prevention ability of curcumin, whey protein was used to nanoencapsulate at three different ratios such as 70:30, 50:50 and 35:65 for the first time. The drug loading, entrapment efficiency and structural changes of curcumin was confirmed by quantitative NMR spectroscopy. The nanoparticles prepared using the three ratios had an average diameters of 236.5±8.8, 212±3.4, and 187±11.4nm, as well as zeta (ζ) potentials of -13.1,-9.26, and -4.63mV, respectively, at pH 7.0. The cytotoxicity assay was performed for human colon and prostate cancer (SW480 and LNCap) by MTT assay and results showed significantly higher cytotoxicity of nanoencapsulated curcumin (NEC) (equivalent to 30.91, 20.70 and 16.86µM of NEC-1, 2 and 3 respectively), as compared to plain curcumin at 50µM after 72h of treatment. Cytotoxicity was also confirmed by microscopy of treated cells stained with acridine orange and propidium iodide. The cells treated with 50µM of curcumin, 30.91µM (NEC-1), 20.70µM (NEC-2) and 16.86µM (NEC-3) showed enhanced activation of p53 and elevated bax/Bcl2 expression (NEC-3), increased cytochrome-c in cytosol (NEC-2) confirming the enhanced cytotoxicity. To confirm the increased bioavailability, the intracellular curcumin was measured using fluorescence intensity. The fluorescent signal for intracellular curcumin was increased by 12, 30, and 21% for NEC-1, NEC-2, and NEC-3 respectively as compared to plain curcumin at 4h. Based on these results, we conclude that nanoencapsulated curcumin with whey protein will have potential to be considered for clinical applications for future studies.

Inhibitory Effect of Cinnamaldehyde, Citral, and Eugenol on Aflatoxin Biosynthetic Gene Expression and Aflatoxin B1 Biosynthesis in Aspergillus flavus

In order to reveal the inhibitory effects of cinnamaldehyde, citral, and eugenol on aflatoxin biosynthesis, the expression levels of 5 key aflatoxin biosynthetic genes were evaluated by real-time PCR. Aspergillus flavus growth and AFB1 production were completely inhibited by 0.80 mmol/L of cinnamaldehyde and 2.80 mmol/L of citral. However, at lower concentration, cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L) significantly reduced AFB1 production with inhibition rate of 68.9%, 95.4%, and 41.8%, respectively, while no effect on fungal growth. Real-time PCR showed that the expressions of aflR, aflT, aflD, aflM, and aflP were down-regulated by cinnamaldehyde (0.40 mmol/L), eugenol (0.80 mmol/L), and citral (0.56 mmol/L). In the presence of cinnamaldehyde, AflM was highly down-regulated (average of 5963 folds), followed by aflP, aflR, aflD, and aflT with the average folds of 55, 18, 6.5, and 5.8, respectively. With 0.80 mmol/L of eugenol, aflP was highly down-regulated (average of 2061-folds), followed by aflM, aflR, aflD, and aflT with average of 138-, 15-, 5.2-, and 4.8-folds reduction, respectively. With 0.56 mmol/L of citral, aflT was completely inhibited, followed by aflM, aflP, aflR, and aflD with average of 257-, 29-, 3.5-, and 2.5-folds reduction, respectively. These results suggest that the reduction in AFB1 production by cinnamaldehyde, eugenol, and citral at low concentration may be due to the down-regulations of the transcription level of aflatoxin biosynthetic genes. Cinnamaldehyde and eugenol may be employed successfully as a good candidate in controlling of toxigenic fungi and subsequently contamination with aflatoxins in practice.

Auraptene, a Major Compound of Supercritical Fluid Extract of Phalsak (Citrus Hassaku Hort ex Tanaka), Induces Apoptosis through the Suppression of mTOR Pathways in Human Gastric Cancer SNU-1 Cells

The supercritical extraction method is a widely used process to obtain volatile and nonvolatile compounds by avoiding thermal degradation and solvent residue in the extracts. In search of phytochemicals with potential therapeutic application in gastric cancer, the supercritical fluid extract (SFE) of phalsak (Citrus hassaku Hort ex Tanaka) fruits was analyzed by gas chromatography-mass spectrometry (GC-MS). Compositional analysis in comparison with the antiproliferative activities of peel and flesh suggested auraptene as the most prominent anticancer compound against gastric cancer cells. SNU-1 cells were the most susceptible to auraptene-induced toxicity among the tested gastric cancer cell lines. Auraptene induced the death of SNU-1 cells through apoptosis, as evidenced by the increased cell population in the sub-G1 phase, the appearance of fragmented nuclei, the proteolytic cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP) protein, and depolarization of the mitochondrial membrane. Interestingly, auraptene induces an increase in the phosphorylation of Akt, which is reminiscent of the effect of rapamycin, the mTOR inhibitor that triggers a negative feedback loop on Akt/mTOR pathway. Taken together, these findings provide valuable insights into the anticancer effects of the SFE of the phalsak peel by revealing that auraptene, the major compound of it, induced apoptosis in accompanied with the inhibition of mTOR in SNU-1 cells.

Flavor chemistry of lemon-lime carbonated beverages

The most potent aroma-active components of Sprite (SP), Sierra Mist (SM), and 7UP (7UP) were identified. Aroma extracts were prepared by liquid–liquid continuous extraction/solvent-assisted flavor evaporation (LLCE/SAFE). Twenty-eight compounds were detected by gas chromatography–olfactometry (GC-O) with linalool (floral, lavender), octanal (pungent orange), and 2,3-dehydro-1,8-cineole (minty) determined to be predominant aroma compounds based on their high flavor dilution (FD) factors by aroma extract dilution analysis (AEDA). The data indicate that lemon-lime flavor is composed of a small number of compounds (22 at the most in SM), and only a subset of these may be important because many compounds were detected only at low FD factors. Predominant aroma compounds (23) were quantified using static headspace solid phase microextraction (SPME) combined with stable isotope dilution assays (SIDA). In contrast to FD factors, the calculated odor-activity values (OAVs) indicate that octanal and limonene make the greatest contribution to the overall aroma of lemon-lime carbonated beverages, followed by nonanal, decanal, linalool, 1,8-cineole, and geranyl acetate. The results demonstrate that lemon-lime carbonated beverages share many of the same compounds but the relative abundance of these compounds varies by brand.

Inhibitory effect of essential oils on Aspergillus ochraceus growth and ochratoxin A production

Ochratoxin A (OTA) is a mycotoxin which is a common contaminant in grains during storage. Aspergillus ochraceus is the most common producer of OTA. Essential oils play a crucial role as a biocontrol in the reduction of fungal contamination. Essential oils namely natural cinnamaldehyde, cinnamon oil, synthetic cinnamaldehyde, Litsea citrate oil, citral, eugenol, peppermint, eucalyptus, anise and camphor oils, were tested for their efficacy against A. ochraceus growth and OTA production by fumigation and contact assays. Natural cinnamaldehyde proved to be the most effective against A. ochraceus when compared to other oils. Complete fungal growth inhibition was obtained at 150-250 µL/L with fumigation and 250-500 µL/L with contact assays for cinnamon oil, natural and synthetic cinnamaldehyde, L. citrate oil and citral. Essential oils had an impact on the ergosterol biosynthesis and OTA production. Complete inhibition of ergosterol biosynthesis was observed at ≥ 100 µg/mL of natural cinnamaldehyde and at 200 µg/mL of citral, but total inhibition was not observed at 200 µg/mL of eugenol. But, citral and eugenol could inhibit the OTA production at ≥ 75 µg/mL and ≥ 150 µg/mL respectively, while natural cinnamaldehyde couldn't fully inhibit OTA production at ≤ 200 µg/mL. The inhibition of OTA by natural cinnamaldehyde is mainly due to the reduction in fungal biomass. However, citral and eugenol could significant inhibit the OTA biosynthetic pathway. Also, we observed that cinnamaldehyde was converted to cinnamic alcohol by A. ochraceus, suggesting that the antimicrobial activity of cinnamaldehyde was mainly attributed to its carbonyl aldehyde group. The study concludes that natural cinnamaldehyde, citral and eugenol could be potential biocontrol agents against OTA contamination in storage grains.

Apoptotic effect of genistein on human colon cancer cells via inhibiting the nuclear factor-kappa B (NF-κB) pathway

Genistein possesses a wide variety of biological activities, and it is best known for its ability to inhibit cancer progression. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell cycle arrest and apoptosis as well as the antioxidant functions. Nuclear factor kappa-B (NF-κB) is a signaling pathway that controls transcriptional activation of genes important for the tight regulation of many cellular processes and is aberrantly expressed in many types of cancer. Inhibitors of NF-κB pathway have shown potential anti-tumor activities. However, it is not fully elucidated in colon cancer. In the present study, we demonstrated that genistein could induce apoptosis in human colon cancer LoVo and HT-29 cells through inhibiting NF-κB pathway, as well as downregulation of Bcl-2 and upregulation of Bax, thus providing basis for clinical application of genistein in colon cancer cases.

Essential oils and their constituents as anticancer agents: a mechanistic view

Exploring natural plant products as an option to find new chemical entities as anticancer agents is one of the fastest growing areas of research. Recently, in the last decade, essential oils (EOs) have been under study for their use in cancer therapy and the present review is an attempt to collect and document the available studies indicating EOs and their constituents as anticancer agents. This review enlists nearly 130 studies of EOs from various plant species and their constituents that have been studied so far for their anticancer potential and these studies have been classified as in vitro and in vivo studies for EOs and their constituents. This review also highlights in-depth various mechanisms of action of different EOs and their constituents reported in the treatment strategies for different types of cancer. The current review indicates that EOs and their constituents act by multiple pathways and mechanisms involving apoptosis, cell cycle arrest, antimetastatic and antiangiogenic, increased levels of reactive oxygen and nitrogen species (ROS/RNS), DNA repair modulation, and others to demonstrate their antiproliferative activity in the cancer cell. The effect of EOs and their constituents on tumour suppressor proteins (p53 and Akt), transcription factors (NF- κB and AP-1), MAPK-pathway, and detoxification enzymes like SOD, catalase, glutathione peroxidase, and glutathione reductase has also been discussed.

Apoptosis mediated anti-proliferative effect of compound isolated from Cassia auriculata leaves against human colon cancer cell line

A compound was isolated from Cassia auriculata leaves and characterized by high-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC-MS), UV-vis spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The in vitro anticancer effect of the compound isolated from C. auriculata was evaluated in human colon cancer cells HCT 15 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cytotoxicity, nuclear morphology analysis and measurement of lactate dehydrogenase. The isolated compound 4-(2,5 dichlorobenzyl)-2,3,4,5,6,7 hexahydro7(4 methoxyphenyl)benzo[h][1,4,7] triazecin8(1H)-one showed 50% inhibition of HCT 15 cells when tested at 20μg/ml after 24h incubation. Cytotoxicity, nuclear morphology and lactate dehydrogenase assays clearly show potent anticancer activity of the isolated compound against colon cancer. Thus, the in vitro findings suggest that the compound isolated from C. auriculata leaves have potent anti-cancer properties with possible clinical applications.

PI3K/Akt pathway involving into apoptosis and invasion in human colon cancer cells LoVo

In this study we determined the effects of Curcumin on human colon cancer cells line LoVo. We found that Curcumin significantly inhibited the proliferation, migration and invasion, and clone formation of LoVo cells in a dose-dependent manner. Curcumin also dose-dependently reduced the phosphorylation of proteins Akt and increased expression levels of the genes caspase-3, cytochrome-c, Bax mRNA in LoVo cells. In addition, Curcumin dose-dependently decreased gene Bcl-2 mRNA expression. Similar results were observed in LoVo cells treated with LY294002. These in vitro studies suggest that Curcumin may play its anti-cancer actions partly via suppressing PI3K/Akt signal pathway in LoVo cells.

Citrus limonoids and curcumin additively inhibit human colon cancer cells

In the current study, we examined the ability of limonoids, including limonin, limonin glucoside (LG) and curcumin, to inhibit proliferation of human colon cancer (SW480) cells. Additionally, we studied the effect of combining these two classes of natural compounds on inhibition of proliferation and the possible mode of cytotoxicity. The SW480 cells were treated with compounds individually and in combination to understand the effect on cell death, DNA fragmentation, caspase-3 activity and the expression of Bax, Bcl-2 and caspase-3 proteins. Results of cell proliferation assays suggest that combinations of limonoids with curcumin at three different ratios (1 : 3, 1 : 1 and 3 : 1) to a final concentration of 50 ppm demonstrated up to 96% inhibition of cell proliferation. The MTT assay results were also confirmed by counting viable cells. Further, incubation of cells with combinations of limonoids and curcumin resulted in elevation of total cellular caspase-3 activity by 3.5-4.0 fold along with a 2- to 4-fold increase in the Bax/Bcl-2 ratio. The expression of pro-caspase-3 and its cleaved products in cells treated with curcumin (individually or combination) indicates higher potency of the combination to induce apoptosis. For the first time, this study provides compelling evidence of the pharmacodynamic additive effect of limonoids and curcumin in inhibiting human colon cancer cells. The above results were also confirmed by fluorescence microscopy of SW480 cells treated with limonoids, curcumin and combination, after tagging with fluorescent probes. These results suggest that consumption of curcumin and limonoids together may offer greater protection against colon cancer.

Anticancer activity of essential oils: a review

Natural essential oil constituents play an important role in cancer prevention and treatment. Essential oil constituents from aromatic herbs and dietary plants include monoterpenes, sesquiterpenes, oxygenated monoterpenes, oxygenated sesquiterpenes and phenolics among others. Various mechanisms such antioxidant, antimutagenic and antiproliferative, enhancement of immune function and surveillance, enzyme induction and enhancing detoxification, modulation of multidrug resistance and synergistic mechanism of volatile constituents are responsible for their chemopreventive properties. This review covers the most recent literature to summarize structural categories and molecular anticancer mechanisms of constituents from aromatic herbs and dietary plants.

Anti-proliferative effect of a compound isolated from Cassia auriculata against human colon cancer cell line HCT 15

The compound was isolated from leaves of Cassia auriculata and its structure was characterized using high-performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC-MS), UV-vis spectroscopy (UV-vis), fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, cytotoxicity, nuclear morphology and lactate dehydrogenase assay of isolated compound was tested against human colon cancer cell line HCT 15. The isolated compound, 4-(4-chlorobenzyl)-2,3,4,5,6,7-hexahydro-7-(2-ethoxyphenyl)benzo[h][1,4,7]triazecin-8(1H)-one at 25μg/ml concentration and by 48h showed 50% inhibition of human colon cancer cells (HCT 15). The results suggest that isolated compound from C. auriculata has potential to prevent colon cancer cell line.

Volatile Composition and Biological Activity of Key Lime Citrus aurantifolia Essential Oil

The essential oil of Citrus aurantifolia (Christm) Swingle fruits (limes) was studied for its potential spasmolytic effects in relation to its chemical composition. The essential oil, extracted by hydrodistillation (HD), was analyzed by GC-FID and GC-MS. The antispasmodic activity was evaluated on isolated rabbit jejunum, aorta and uterus. The results indicated that the essential oil of C aurantifolia possesses important spasmolytic properties, which are likely to be due to its major constituents, limonene (58.4%), β-pinene (15.4%), γ-terpinene (8.5%), and citral (4.4%).

D-limonene rich volatile oil from blood oranges inhibits angiogenesis, metastasis and cell death in human colon cancer cells

AIMS

To identify the chemical constituents of volatile oil from blood orange (Citrus sinensis (L) Osbeck) and understand the possible mechanisms of inhibition of colon cancer cell proliferation.

MAIN METHODS

Volatile oil was obtained from blood oranges by hydro-distillation. Nineteen compounds were identified by GC-MS and d-limonene was found to be the major component. The blood orange volatile oil was formulated into an emulsion (BVOE) and examined for its effects on viability of colon cancer cells. In addition, experiments were performed to understand the possible mechanism of proliferation inhibition, angiogenesis and metasasis by BVOE.

KEY FINDINGS

BVOE exhibited dose-dependent inhibition of cell proliferation and induced apoptosis in the colon cancer cells, as confirmed by flow cytometry. Immunoblotting of colon cancer cells treated with BVOE shows dose-dependent induction of Bax/Bcl2) and inhibition of vascular endothelial growth factor (VEGF). Furthermore, treatment of serum starved SW480 and HT-29 cells with 100μg/ml BVOE suggested the inhibition of VEGF and markers associated with inhibition of angiogenesis. The antiangiogenic activity of BVOE was also confirmed by inhibition of in vitro tube formation in human umbilical vein endothelial cells. Dose-dependent anti-metastasis activity and blockage of vascular endothelial growth factor receptor 1 (VEGFR1) binding following treatment with BVOE were confirmed by cell migration assays and immunoblots to detect decreased expression of matrix metalloproteinases (MMP-9).

SIGNIFICANCE

The results of this study provide persuasive evidence of the apoptotic and anti-angiogenesis potential of BVOE in colon cancer cells. The extent of induction of apoptosis and inhibition of angiogenesis suggest that BVOE may offer great potential for prevention of cancer and may be appropriate for further studies.

Cytotoxic effect of Eucalyptus citriodora resin on human hepatoma HepG2 cells

The aim of this study was to evaluate the antiproliferative effect of Eucalyptus citriodora resin (ECR) on human hepatoma HepG2 cells. The results from MTT assay and LDH leakage analysis showed that water extracts of ECR (WEECR) in the dose range of 0-500 μg/ml displayed stronger cytotoxic effects on HepG2 cells than other organic solvent extracts of ECR. By flow cytometry analysis, WEECR slowed down the cell cycle at the G0/G1 phase after 24 h of incubation. Moreover, WEECR treatment induced an apoptotic response in HepG2 cells. WEECR-induced apoptosis was in association with the attenuation of mitochondrial transmembrane potentials (ΔΨ(m)), increased Bax/Bcl-2 ratio and activation of caspase-3. In addition, WEECR contained high concentration of phenolics and flavonoids, which may be responsible for the potent cytotoxicity of WEECR on HepG2 cells. Taken together, WEECR may be a potent antihepatoma agent due to apoptosis in HepG2 cells.

The anti-proliferative effects of a palm oil-derived product and its mode of actions in human malignant melanoma MeWo cells

Melanoma incidence and mortality have risen dramatically in recent years. No effective treatment for metastatic melanoma exists; hence currently, an intense effort for new drug evaluation is being carried out. In this study, we investigated the effects of a palm oil-derived nanopolymer called Bio-12 against human malignant melanoma. The nanopolymers of Bio-12 are lipid esters derived from a range of fatty acids of palm oil. Our study aims to identify the anti-proliferative properties of Bio-12 against human malignant melanoma cell line (MeWo) and to elucidate the mode of actions whereby Bio-12 brings about cell death. Bio-12 significantly inhibited the growth of MeWo cells in a concentration- and time- dependent manner with a median inhibitory concentration (IC₅₀) value of 1/25 dilution after 72 h but was ineffective on human normal skin fibroblasts (CCD-1059sk). We further investigated the mode of actions of Bio-12 on MeWo cells. Cell cycle flow cytometry demonstrated that MeWo cells treated with increasing concentrations of Bio-12 resulted in S-phase arrest, accompanied by the detection of sub-G1 content, indicative of apoptotic cell death. Induction of apoptosis was further confirmed via caspase (substrate) cleavage assay which showed induction of early apoptosis in MeWo cells. In addition, DNA strand breaks which are terminal event in apoptosis were evident through increase of TUNEL positive cells and formation of a characteristic DNA ladder on agarose gel electrophoresis. Moreover, treatment of MeWo cells with Bio-12 induced significant increase in lactate dehydrogenase (LDH) activity. These results show that Bio-12 possesses the ability to suppress proliferation of human malignant melanoma MeWo cells and this suppression is at least partly attributed to the initiation of the S-phase arrest, apoptosis and necrosis, suggesting that it is indeed worth for further investigations.