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.

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.

[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.

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.

[Effect of ripening and drying on pro-vitamin A carotenoid content in pepper (Capsicum annuum var. Anaheim)]. / Efecto de la maduración y el secado en el contenido de carotenoides pro-vitamina A en chile (Capsicum annuum var. Anaheim).

The content of the principal carotenes with biological activity (alpha-, beta, gamma-carotene and beta-criptoxantine) in green pepper (Capsicum annuum var. Anaheim) was determined in order to investigate the vitamin A content during the traditional process of ripening and drying. The analytical technique used was high pressure liquid chromatography (HPLC) with a Novapack C18 column and acetonitrile/methanol/tetrahydrofuran (58V:35V:7V) as a mobile phase. The results showed differences in vitamin A activity of 7.2 +/- 0.8, 51.1 +/- 2.4 and 55.3 +/- 1.2 micrograms of RE/g dry matter for immature, mature and dry pepper fruit respectively (p < 0.05). Approximately 95% of total activity was due to beta-carotene being synthesized faster than the other carotenes under study during the ripening process. Total vitamin A activity reached its highest value at 14 days after harvest (2738.8 +/- 128.6 micrograms RE/100 g of edible portion), with a decrease in activity with time.

[Effect of home-processing in the preparation of pinto beans (Phaseolus vulgaris L.) on the tannin content and nutritive value of proteins]. / Efecto de los tratamientos caseros en la preparación de frijol pinto (Phaseolus vulgaris L.) sobre el contenido de taninos y valor nutritivo de las protéinas.

A 3(2) factor design was carried out in order to investigate the different home-cooking treatments applied in the preparation of pinto beans (Phaseolus vulgaris L.) on the nutritive value of their protein. The factors studied were previous soaking, type of cooking and addition of cooking broth. Biological evaluation of the protein was performed, and the protein efficiency ratio (PER) and apparent digestibility of the protein (DAP) values were obtained. The tannin content was measured in hulls, cotyledons and in the cooking broths of each experimental treatment. The most significant effect of the PER value was the type of cooking (P less than 0.0001), followed by the addition of cooking broth (P less than 0.05) as well as a significant interaction between cooking method and addition of broth (P less than 0.025). Soaking did not have significant effects per se or through its interactions in relation to PER. The highest values for PER and DAP were obtained with the boiling treatment without broth. The detrimental effect of the cooking broth can be explained by its tannin content (108.5-272.25 mg Eq. catechin/100g).

[Characterization of the nutritional potential of tepari bean (Phaseolus acutifolius) grown in Mexico]. / Caracterización del potencial nutricional del frijol tepari (Phaseolus acutifolius) cultivado en México.

The chemical, physical, antiphysiological and biological quality of the protein of three varieties (white, brown and black) of tepary bean (Phaseolus acutifolius) were studied. Its proximate composition was determined, as well as water absorption, hardness of the seed, tannin content, trypsin inhibitors and lectins. Beans were also submitted to differential scanning calorimetry of the starch. The biological quality of its proteins was also established, based on the protein efficiency ratio (PER) and protein apparent digestibility. It was found that the protein content of the bean was high (25%). The white variety had the highest water absorption and the lowest hardness of the seed when compared with the other varieties (p less than 0.05). The black variety had a lower starch gelatinization energy and a higher cooking time than the white and brown varieties. The tannin content of the three varieties was low, particularly in the white one. The trypsin inhibitor and lectin content were relatively high in the raw beans, but disappeared almost totally during cooking. The biological quality of the tepari proteins was higher than that of the common bean cultivated under the same conditions, More evidently so in the white bean (PER = 1.48 as compared to 1.23 in pinto bean). It can be concluded that the tepary bean is a potentially good protein source and has also a great potential ad donor of genes for the obtention of better bean varieties from the culinary, nutritional and toxicological points of view.

[Evaluation of chemical and nutritional characteristics of the seed of the rubber tree (Hevea brasiliensis)]. / Evaluación de algunas características quimico--nutricionales de la semilla del arbol de hule (Hevea brasiliensis).

Some chemical and nutritional characteristics of the rubber seed Hevea brasiliensis were studied. The protein content, its amino acid composition as well as the iron, calcium, phosphorus and cyanide (free and bound) concentrations, were determined in the dehulled seed. The effect of soaking, cooking, soaking-cooking and cooking-fat extraction procedure of the seed on the cyanide content and its in vivo protein utilization, was also evaluated. The protein quality was biologically assessed using the protein efficiency ratio (PER). The protein content of the seed was 18%, and the most limiting amino acid was threonine, with a chemical score of 71.6. The iron, calcium and phosphorus contents were 6.2, 109 and 429 mg/100 g, respectively. Its fat content was 48% with a total energy value of 702 kcal/100 g (2,948 Kj/100 g). The total cyanide content in the fresh seed was 130-230 mg/100 g; 6% was in the free form and 94% as bound cyanide. The most effective treatment for reducing the cyanide content was found to be 20 hours of soaking in water, combined with one hour of cooking. The raw seed had a low nutritive value and produced weight loss and death when fed to rats. The protein value, however, improved upon the seed treatment, reaching PER values close to those found in traditional cereals such as corn. It is therefore concluded that the seed of Hevea brasiliensis is a good source of energy, calcium, valine, isoleucine, phenylalanine and tyrosine. In contrast, it is a poor source of threonine, leucine and lysine. Its cyanide content is high, but when removed by treatment, such as soaking in water, cooking or fat extraction, the protein utilization can be improved.