Moringa oleifera leaves alleviated inflammation through downregulation of IL-2, IL-6, and TNF-α in a colitis-associated colorectal cancer model.

New chemopreventive alternatives are needed due to the rising worldwide incidence of colorectal cancer. The objective was to evaluate the chemopreventive activity of Moringa oleifera leaves (MO) in a colitis-associated colon carcinogenesis model. We hypothesized that MO contain bioactive compounds capable of modulating the expression of genes involved in the inflammatory response and carcinogenesis. Forty-eight male mice (CD-1) were divided into six groups; 1: Healthy control; 2: Positive control induced with azoxymethane (AOM, 10 mg/Kg body weight, intraperitoneal injection) and three cycles of dextran sodium sulfate (DSS, 1.5% in drinking water); groups 3, 4, and 5 were induced with AOM/DSS and supplemented with 5%, 10%, and 20% of MO, respectively; group 6: had no disease induction and supplemented with 20% of MO. Mice were treated for 12 weeks and euthanized. Significant differences (p < 0.05) were found for the moringa-administered groups in morphological and histopathological parameters compared to the AOM/DSS control. A decrease in myeloperoxidase activity (~50%) and lipid peroxidation (1.9-3.1 times) were found in groups with 10% and 20% of MO compared to the AOM/DSS control (p < 0.05). The group supplemented with 10% MO showed a significant increase (~3 times) in butyrate and propionate in fecal and cecal content. Groups supplemented with 10%, and 20% MO showed a reduction in proinflammatory cytokines in serum (MCP-1, IL-6, TNF-α) compared to the AOM/DSS control. Treatment with 10% MO induced differential expression of 65 genes in colon tissue such as IL-2, IL-6, TNF, IL-1ß, and INF-γ. MO downregulated proinflammatory mediators showing chemopreventive properties against inflammatory response and colon carcinogenesis.

Physicochemical and nutraceutical properties of moringa (Moringa oleifera) leaves and their effects in an in vivo AOM/DSS-induced colorectal carcinogenesis model.

Moringa (Moringa oleifera) is a plant that has generated great interest in recent years because of its attributed medicinal properties. The aim of this study was to characterize the bioactive compounds of moringa leaves (MO) and evaluate their effect on a colorectal carcinogenesis model. Twenty-four male CD-1 mice were divided into 4 groups: Group 1 fed with basal diet (negative control/NC); Group 2 received AOM/DSS (positive control); Groups 3 and 4 were fed with basal diet supplemented with moringa leaves (2.5% w/w and 5% w/w, respectively) for 12weeks. Moringa leaves exhibited a high content of dietary fiber (~18.75%) and insoluble dietary fiber (2.29%). There were identified 9 phenolic compounds whereas the chlorogenic and ρ-coumaric acid showed the higher contents (44.23-63.34µg/g and 180.45-707.42µg/g, respectively). Moringa leaves decreased the activity of harmful fecal enzymes (ß-glucosidase, ß-glucuronidase, tryptophanase and urease up to 40%, 43%, 103% and 266%, respectively) as well tumors incidence in male CD1-mice (~50% with 5% w/v of moringa dose). These findings suggest that the bioactive compounds of moringa such as total dietary fiber and phenolic compounds may have chemopreventive capacity. This is the first study of the suppressive effect of moringa leaves in an in vivo model of AOM/DSS-induced colorectal carcinogenesis.

Hibiscus sabdariffa L. extracts inhibit the mutagenicity in microsuspension assay and the proliferation of HeLa cells.

Hibiscus sabdariffa L. is used as a refreshing beverage and as a traditional medicine. The objective of this study was to determine the in vitro effect of phenolic compounds present in aqueous, ethyl acetate, and chloroform extracts of H. sabdariffa against mutagenicity of 1-nitropyrene (1-NP), and also the antiproliferative effect of these extracts. Inhibition of cell proliferation and DNA fragmentation were tested on transformed human HeLa cells. The hot aqueous extract (HAE) contained 22.27 +/- 2.52 mg of protocatechuic acid (PCA) per gram of lyophilized dried extract, and was not statistically different from the cold aqueous or chloroform extracts; the ethyl acetate extract produced the least amount of PCA. The H. sabdariffa extracts inhibited mutagenicity of 1-NP in a dose-response manner. The inhibition rate on HeLa cells of HAE was also dose-dependent. The HAE did not induce DNA fragmentation. The results suggest that H. sabdariffa L. extracts have antimutagenic activity against 1-NP and decrease the proliferation of HeLa cells, probably due to phenolic acid composition.

Inhibition of liver carcinogenesis in Wistar rats by consumption of an aqueous extract from leaves of Ardisia compressa.

This study evaluates the chemopreventive effect of an aqueous extract of dried leaves of Ardisia compressa against liver cancer. A rat liver assay that mimics progressive forms of human disease was used as a carcinogenesis model. Forty-five male Wistar rats (180-200 g body weight) were injected intraperitoneally on day 1 with a single dose (100 mg/kg) of diethylnitrosamine (DEN), and also received via gavage 20 mg/kg acetylaminofluorene (2-AAF), on days 7, 8 and 9. The rats were randomly divided into four groups (n=15). Control groups (Group 1 and Group 2) had free access to water. Group 3 received 0.5% (w/v) of A. compressa tea for 10 days before treatment and during the study as the sole source of fluid until the rats were killed. A fourth group of 15 rats received no carcinogen or promoter but did receive 0.5%, (w/v) of A. compressa tea. All animals had 70% partial hepatectomy at day 10. The incidences of hepatocellular foci, nodules and carcinoma were significantly smaller in Group 3 than in Group 2 (P<0.01). A. compressa tea consumption alone (Group 4) did not induce the development of foci, nodules or carcinomas (P<0.01). The striking observation of this study was that consumption of A. compressa tea resulted in complete inhibition of the chemically-induced hepatocarcinogenesis in Wistar rats.

El efecto quimioprotector del té y sus compuestos / The chemo-protector effects of tea and its components

Tea has been consumed worldwide since ancient times to maintain and improve health. Its main active components are a type of polyphenols known as flavonoids, which include catechins and theaflavins. Several epidemiological studies suggest that the consumption of green tea could prevent cancer development in humans. Likewise, animal studies have shown that green tea consumption may inhibit the development of prostate and breast cancer. It has been shown that, through several mechanisms, tea polyphenols present antioxidant and anticarcinogenic activities, thus affording several health benefits. It is important to better characterize tea components, to study their bio-availability and bio-transformation in vivo and to conduct clinical studies of its main active compounds.

Purification and acute toxicity of a lectin extracted from tepary bean (Phaseolus acutifolius).

Lectins are proteins or glycoproteins known for their ability to agglutinate cells, especially erythrocytes. Several lectins are toxic to mammalian cells both in vitro and in vivo, inhibit growth when incorporated into the diet and are toxic when injected into animals. On the other hand, the use of lectins has been suggested as an alternative in cancer treatment. The objective of the present study was to evaluate the acute toxicity of a lectin extracted and purified from tepary bean (Phaseolus acutifolius, G-400-34) on CD-1 mice. Fetuin affinity chromatography, electrophoretic pattern and Western-immunoblot techniques were used to purify and partially characterize the lectin. This tepary bean line presented high levels of lectin activity. Western blot revealed that the sera reacted with the known PHA subunits in the 34-40 kD range. Four major lectin and lectin-related glycopolypeptides were identified. The purified lectin from tepary bean was a tetrameric one that ran at about 115-120 kD. The LD(50) (ip) was 1100 mg/kg body weight for males and 1120 mg/kg body weight for females. The body weight of experimental animals decreased in a dose-dependent manner. The main target organs affected were small intestine, spleen and thymus. The lectin isolated from tepary bean showed affinity towards fetuin, with high agglutination values and low acute toxicity.

alpha-Tocopherol modulates liver toxicity of the pyrethroid cypermethrin.

The objective of the current study was to analyze the hepatotoxic effect caused by cypermethrin (CYP) in rats, and to evaluate the possible protective effect of the antioxidant alpha-tocopherol (alpha-T). Fifty male Wistar rats were given daily i.p. doses of 300 mg/kg per day of CYP during 7 days. Half of them were administered three previous doses of 100 mg/kg per day of alpha-T, followed by seven subsequent oral doses of 40 mg/kg per day of alpha-T. The levels of biochemical indicators and histological liver damage were determined, as well as DCVA in urine. CYP altered the lipid metabolism. Such alterations were inhibited 32% by alpha-T, except for LDL. Alterations in AST were modulated in 29%. In the histology, alpha-T reduced mitochondria damage, and swelling of the endoplasmic reticulum of the liver cells. The results suggest that alpha-T can modify CYP metabolism, changing the lipidic profile and the histological analysis.

Effect of lycopene on lipid peroxidation and glutathione-dependent enzymes induced by T-2 toxin in vivo.

Lycopene, obtained from fresh tomatoes, was incorporated into the chicks diet. The treatments were: (1) Control, (2) 1.5 mg T-2 toxin/kg body weight/day; (3) 25 mg lycopene/kg body weight/day, (4) 1.5 mg T-2 toxin plus 25 mg lycopene/kg body weight/day. Male broiler chicks, 7-28 days of age, were provided with feed and water ad libitum. Every 7 days, malondialdehyde (MDA) and glutathione (GSH) levels, and enzymatic activities of glutathione-S-transferase (GST), gamma-glutamyltransferase (GGT) and glutathione peroxidase (GP) were evaluated in liver homogenates. Compared to the controls after 7 days of treatment, T-2 toxin increased hepatic MDA concentration (128%). A significant consumption of endogenous antioxidant GSH (45%) was induced as well as a marked increase in hepatic enzymatic activities of GST, GGT, and GP (312, 187, and 324%, respectively). Addition of T-2 plus lycopene, at an approximate ratio of 1:17 in the diet, diminished some parameters measured (P < 0.05). Apparently lycopene participated as an antioxidant agent and also protecting the cellular level of GSH.

[Protein quality of three strains of Mexican mushrooms (Pleurotus ostreatus)]. / Calidad proteínica de tres cepas mexicanas de setas (Pleurotus ostreatus).

The protein quality of fruits bodies of three Pleurotus ostreatus Mexican strains (INIREB-8, CDBB-H-896 and CDBB-H-897) was evaluated. The protein concentration (Nx4.38) ranged from 17.26 to 19.97 g/100 g dry weight; chemical scores were between 74 and 93% with available lysine as a first limiting amino acid in either INIREB-8 and CDBB-H-896 strains or leucine in CDBB-H-897 strain. The nutritional evaluation revealed 67.75 to 68.38% in vitro digestibility. Relative protein values were from 100.06-107.85%, which were lower than soybean meal and whole egg but larger than those of rice, maize, beans, fava beans and pasta, no differences were found between these values and those of skim milk powder, casein plus methionine and albumin. In accordance with the last results we concluded that due to their essential amino acids content, mushroom proteins are a good complement of cereals; furthermore, it is highly recommended to include Pleurotus in the daily diet.

Protection of extract from leaves of Ardisia compressa against benomyl-induced cytotoxicity and genotoxicity in cultured rat hepatocytes.

The potential of the Ardisia compressa extract (EA) was examined regarding its capacity to reduce the cytotoxic effect of benomyl on rat hepatocytes. The protective effect was evaluated by Janus Green dye exclusion method. An approximate 50% cytotoxic effect of benomyl on hepatocytes was observed at 35mug/ml after 2hr of incubation. (-)Epigallocatechin 3-gallato (EGCG) and EA decreased the viability of hepatocytes at concentrations above 3mug/ml and 2.52mug, equivalent to (+)catechin/ml, respectively. A protective effect against benomyl was observed when hepatocytes were previously exposed to EGCG (3mug/ml) or EA (2.52mug, equivalent to (+)catechin/ml) followed by incubation with benomyl (35mug/ml) alone. When EGCG or EA were in contact with cells, either simultaneously or after pretreatment with benomyl, did not protect hepatocytes. EGCG (1.3x10(-2)mug/ml) or EA (9.8x10(-2)mug, equivalent to (+)catechin/ml) inhibited 57% and 34%, respectively, the unscheduled DNA synthesis (UDS) induced by benomyl at a concentration of 23x10(-2)mum, when both were incubated with hepatocytes prior to benomyl. The simultaneous incubation of benomyl with EGCG or EA did not protect the cell against the genotoxic effect of benomyl. These results indicate that the dried leaves extract of Ardisia compressa protect rat hepatocytes from benomyl-induced cytotoxicity and genotoxicity.

Comparative study of enzymes related to proline metabolism in tepary bean (Phaseolus acutifolius) and common bean (Phaseolus vulgaris) under drought and irrigated conditions, and various urea concentrations.

There are several mechanisms used by plants for survival in adverse environments such as drought, high temperature and salinity. The objective of this study was to evaluate the drought tolerance of tepary bean as a function of biochemical processes linked to isozyme synthesis and changes in enzymatic activity related to proline metabolism. Mature seeds of common beans var. flor de mayo, Phoseolus vulgaris and tepary beans Phaseolus acutifolius were grown under two water conditions (irrigation and drought), and four levels of urea. Vertical electrophoresis and spectrophotometric techniques were used to evaluate protein patterns, glutamate dehydrogenase (GDH), proline oxidase (PO) and pyrroline-5-carboxylate reductase (P5C reductase) enzyme activities. These enzymes were studied because they are directly related to protein synthesis. Electrophoretic patterns showed more proteins in tepary beans than in common beans with limited irrigation. GDH showed only one isozyme, with a molecular weight between 240) to 270 kDa. A decrease in PO activity was observed in common beans under drought stress with a value of 237 micromol/min, in comparison to irrigation conditions of 580 micromol/min. GDH and P5C reductase enzymes have had higher activity in common beans than in tepary beans under water stress. There was a significant difference only in glutamate dehydrogenase enzyme with respect to urea level. The results suggest that drought tolerance of tepary beans is due to biochemical processes related to proline metabolic enzymes.

Cypermethrin increases apo A-1 and apo B mRNA but not hyperlipidemia in rats.

The hepatotoxic effect of cypermethrin and the expression of hepatic genes at the mRNA level, as molecular markers of liver damage, were evaluated in rats following exposure to cypermethrin. The expression of hepatic genes was compared with conventional liver functional tests, and correlations were made by studying the liver at the ultrastructural level. Cypermethrin treated rats presented a significant decrease, of 79% and 22%, on the expression of albumin and apo E genes at 5 days, respectively. The levels of apo A-1 and apo B mRNA were increased up to four- and fivefold, respectively. This increase did not correlate with the serum values of HDL and VLDL lipoprotein particles. Intracytoplasmic lipid droplets were observed after the first 2 days following cypermethrin administration, suggesting that apo A-1 and B mRNA were translated but not secreted. There were significant correlations between the low values of the albumin gene expression, the decrease in the HDL concentrations, and the ultrastructural alterations, respectively. These alterations were mainly a large amount and increased size of mitochondria in the animals exposed to cypermethrin. It is concluded that under the experimental conditions used, cypermethrin may alter the metabolism of lipids and proteins in rat liver.

[Chemical composition of three Mexican strains of mushrooms (Pleurotus ostratus)]. / Composición química de tres cepas mexicanas de setas (Pleurotus ostreatus).

The chemical composition of three Mexican strains of Pleurotus ostreatus (INIREB-8, CDBB-H-896 and CDBB-H-897), were determined. The mushrooms were cultivated on wheat straw in a greenhouse (22-28 degrees C temperature and 80 +/- 5% of relative humidity). Fruits bodies of P. ostreatus contained (all values are expressed in g/100 g dry wt.), protein (N x 6.25): 24.64 +/- 0.21-28.50 +/- 0.26; lipids: 1.10 +/- 0.16-1.85 +/- 0.22; mineral matter: 7.66 +/- 0.23-8.79 +/- 0.25; dietary fibre: 32.14 +/- 0.14-36.81 +/- 0.40; and available carbohydrates: 26.33 +/- 1.04-30.46 +/- 0.21. They contain vitamins (mg/100 g dry wt): riboflavin: 3.31-3.7, thiamin: 1.92-1.96, niacin: 35.98-36.56 and ascorbic acid: 28-35. The main fatty acid was linoleic (0.70-1.19 g/100 g dry wt), it was also reported a low calcium and phosphorus content. Concluding the Pleurotus ostreatus could be a source of some of the complex B vitamins, dietary fiber, protein and linoleic acid.

Effect of carotenoids against genotoxicity of diethylnitrosamine on rat hepatocytes.

Carotenoids have been considered as special nutrients due to their biological activity as provitamin A compounds, and because of their natural antioxidant and anticarcinogenic properties. The main objective of this study was to evaluate the protective effect of carotenoids against the genotoxic cellular damage induced by diethylnitrosamine (DEN), a potent hepatocarcinogen. Normal and freshly isolated hepatocytes were cultured as the biological system. Concentrations of 2.5 and 5 mum DEN caused 1.3 and 2.0 times more DNA T(3)H incorporation, respectively, when compared with control cells. Pure carotenoids, beta-carotene (50 mum), lutein (1 mum) and a carotenoid extract from green peppers (1 mum eq. lutein) were used as functional nutrients to protect the cells. All the carotenoids studied prevented the genotoxic damage caused by 2.5 mum DEN. When 5 mum DEN was used, only beta-carotene and the pepper extract inhibited the damage up to 30-40%. Carotenoids provide a dose-dependent protective effect against DNA damage induced by DEN in isolated hepatocytes.

Antimutagenicity of xanthophylls present in Aztec Marigold (Tagetes erecta) against 1-nitropyrene.

The principal natural food colorants used in modern food manufacture are anthocyanins, betalains, carotenoids, chlorophylls, riboflavin and caramel. Carotenoids (carotenes and xanthophylls) occur naturally in some foods such as carrots, red tomatoes, butter, cheese, paprika, palm oil, corn kernels, marigold petals, annatto, and red salmon. Carotenoids (alpha- or beta-carotene and xanthophylls) are excellent antioxidants and inhibit some types of cancers. In the present study, we used the Salmonella typhimurium tester strain YG1024 in the plate-incorporation test to examine the antimutagenicity of xanthophylls extracted from Aztec Marigold (Tagetes erecta) on 1-nitropyrene (1-NP) mutagenicity. Further, we investigated the effect of lutein on DNA-repair system of tester strain YG1024, using a preincubation test. The possible mechanism of lutein on 1-NP mutagenicity was studied by comparing the absorption spectrum of lutein, 1-NP and lutein plus 1-NP. In a dose-response curve of 1-NP, the mutagenic potency was 4317 revertants/nmol, and the dose of 0.06 microgram of 1-NP/plate was chosen for the antimutagenicity studies. Lutein and xanthophylls from Aztec Marigold (pigments for poultry and human use) inhibited mutagenicity of 1-NP in a dose-dependent manner. Lutein and the pigments were not toxic to the bacteria at the concentrations tested (0.002, 0.02, 0.2, 2.0 and 10 micrograms/plate). The percentages of inhibition of 1-NP mutagenicity were 72%, 92% and 66.2% for lutein (10 micrograms/plate), pigment for poultry use (10 micrograms/plate) and pigment for human use (2 micrograms/plate), respectively. Lutein had no effect on the DNA-repair system of strain YG1024. A new peak was detected at 429 nm when lutein was added at 1-NP, and it was stable throughout the incubation time. The results suggest that the major mechanisms of lutein against 1-NP mutagenicity is the potential formation of a complex between lutein and 1-NP, which could limit the bioavailability of 1-NP.

Antimutagenic activity of natural xanthophylls against aflatoxin B1 in Salmonella typhimurium.

Carotenoids (carotenes and xanthophylls) are excellent antioxidants with antimutagenic and anticarcinogenic properties. They occur naturally in some foods such as carrots, red tomatoes, butter, cheese, paprika, palm oil, corn kernels, Marigold petals, annatto, and red salmon. In the present study, we used the Salmonella plate incorporation test to examine the effect of xanthophylls extracted from Aztec Marigold (Tagetes erecta) on the AFB1 mutagenicity, using tester strain YG1024. The effect of lutein on the DNA-repair system in YG1024 was investigated by a pre-incubation test. In a dose-response curve of AFB1, the mutagenic potency was 1,031 revertants/nmol. The dose of 0.5 microgram AFB1/ plate was chosen for the antimutagenicity studies. Pure lutein and xanthophylls from Aztec Marigold flower (oleoresin and xanthophyll plus) inhibited the mutagenicity of AFB1 in a dose-dependent manner. The pigments were more efficient at inhibiting the AFB1 mutagenicity than pure lutein. The percentages of inhibition on AFB1 mutagenicity were 37, 66, and 76% for lutein, oleoresin, and xanthophyll plus at the dose of 2 micrograms/plate, respectively. Lutein had a modest effect on the DNA-repair system of YG1024. In spectrophotometric studies, a new absorption peak was detected at 378 nm when lutein and AFB1 were incubated together, and lutein reacted with AFB1 metabolites. The results suggest that the inhibitory mechanism of lutein against AFB1 mutagenicity is most probably the result of a combination of the following events: formation of a complex between lutein and AFB1, direct interaction between lutein and AFB1 metabolites, and finally that the lutein may also affect the metabolic activation of AFB1 by S9 and the expression of AFB1-modified Salmonella DNA.

[Antitumor activity of natural substances: lectins and saffron]. / Actividad antitumoral de compuestos naturales: lectinas y azafrán.

A major problem in the use of chemopreventing agents in cancer treatment is the potential toxicity of these drugs to normal cells. One approach to solve this problem is to employ the inhibitors of tumorigenesis which have a natural origin. Within the past few years, natural extracts or purified compounds have become a well-established means for studying varied aspects of cancer. The recent development in plant lectins research is characterized by increasing interest in the biological activities of these lectins, specially in their antitumor effect. Another natural spice-saffron-also become the focus of recent interest as antitumor agent. This review will briefly summarize research on the study of antitumor and anticarcinogenic effects of plant lectins and saffron extract or their constituents. These findings are interpreted and the possible mechanism of antitumor effects of plant lectins and saffron are discussed.

Transfer of lead from lead-glazed ceramics to food.

Recent studies have shown a clear correlation between the use of lead-glazed ceramicware for cooking or food preparation and elevated blood lead levels. Two lots of lead-glazed ceramic bowls, each from a single manufacturing and firing lot were used to measure the sequential leaching of lead into salsa (an acidic food) and beans (a neutral food) stored or cooked in the bowls. The USFDA acetic acid extraction assay was also repeatedly performed on these bowls. The results of the USFDA extraction test were highly variable with levels ranging from 200 to more than 2,000 ppm (regulatory level for rejection is 2 ppm). The levels extracted declined rapidly but the rates were variable. Leaching of lead into salsa (pH = 4.8) was variable and ranged from 8 to greater than 500 ppm. Sequential extractions using salsa yielded variable but declining lead levels. Cooking beans with water in the bowls did not cause substantial leaching (levels between 3 and 8 ppm) and sequential cooking did not show any significant decline over 10 cycles. The results indicate substantial variability in leaching of lead into foods stored or cooked in lead-glazed ceramicware.

Antimutagenicity of ellagic acid against aflatoxin B1 in the Salmonella microsuspension assay.

Ellagic acid (EA) is a phenolic compound with antimutagenic and anticarcinogenic properties. It occurs naturally in some foods such as strawberries, raspberries, grapes, black currants and walnuts. In the present study, we used the Salmonella microsuspension assay to examine the antimutagenicity of EA against the potent mutagen aflatoxin B1 (AFB1) using tester strains TA98 and TA100. Further, we used a two-stage incubation procedure that incorporates washing the bacterial cells free of the incubation mixture after the first incubation to investigate EA and AFB1 interaction. Three different concentrations of AFB1 (2.5, 5 and 10 ng/tube) were tested against five different concentrations of EA for TA98 and TA100. EA significantly inhibited mutagenicity of all doses of AFB1 in both tester strains with the addition of S9. EA alone was not mutagenic at the concentrations tested. The greatest inhibitory effect of EA on AFB1 mutagenicity occurred when EA and AFB1 were incubated together. Lower inhibition was apparent when the cells were first incubated with EA followed by a second incubation with AFB1, and also when the cells were first incubated with AFB1 followed by a second incubation with EA alone. The results of the sequential incubation studies support the hypothesis that one mechanism of inhibition could involve the formation of a chemical complex between EA and AFB1.

Inhibition of colony formation of Hela cells by naturally occurring and synthetic agents.

The present study compared the effects of naturally occurring extracts or compound in combination with synthetic selenium compounds on the colony formation and nucleic acid synthesis of cultured human cervical epitheloid carcinoma cells (Hela). Crude extract of bean (Phaseolus vulgaris) or purified lectin from red kidney bean (Phaseolus vulgaris) in combination with selenomethionine were more effective in inhibiting the colony formation of Hela cells than when these cells were treated with these agents alone. Extracts of saffron (Crocus sativus) and selenite have previously been shown to inhibit the colony formation and nucleic acid synthesis by Hela cells in vitro. In the present study we examined the effects of saffron extract in combination with selenite on the colony formation and DNA and RNA synthesis in Hela cells. We found that the treatment of tumor Hela cells with saffron extract in combination with selenite increased the level of inhibition of the colony formation and nucleic acid synthesis in comparison with cells that were treated with only one of these agents. The inhibitory effect of saffron extract in combination with selenite was modified by intracellular sulfhydryl compounds.