Antioxidant properties of aroma compounds isolated from soybeans and mung beans

Crabgrass (Digitaria sanguinalis) allelochemicals that interfere with crop growth and the soil microbial community

Three chemicals, veratric acid, maltol, and (−)-loliolide, were isolated from crabgrass and their structures were identified by spectroscopic analysis. The chemicals were detected in crabgrass root exudates and rhizosphere soils, and their concentrations ranged from 0.16 to 8.10 μg/g. At an approximate concentration determined in crabgrass root exudates, all chemicals significantly inhibited the growth of wheat, maize, and soybean and reduced soil microbial biomass carbon. Phospholipid fatty acid profiling showed that veratric acid, maltol, and (−)-loliolide affected the signature lipid biomarkers of soil bacteria, actinobacteria, and fungi, resulting in changes in soil microbial community structures. There were significant relationships between crop growth and soil microbes under the chemicals' application. Chemical-specific changes in the soil microbial community generated negative feedback on crop growth. The results suggest that veratric acid, maltol, and (−)-loliolide released from crabgrass may act as allelochemicals interfering with crop growth and the soil microbial community.

Total polyphenols, antioxidant and antiproliferative activities of different extracts in mungbean seeds and sprouts

The aim of this investigation was to evaluate the biological, alcohol dehydrogenase (ADH) and antiproliferative activities of different extracts of mungbean seeds and sprouts. All extracts from the sprouts showed higher contents of total phenolics (TP), total flavonoids (TF), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than from seeds. The highest DPPH and tyrosinase inhibition activities were registered in ethyl acetate (EtOAc) extract. ADH activity of methanol (MeOH), n-hexane (n-hexane) and n-butanol (n-BuOH) extracts from sprouts was significantly higher (P < 0.05) than from seeds. However, the highest ADH activity was found in water extract of seeds. According to 3-(4, 5-dimethylthiazol -2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, extracts from sprouts were more effective against Calu-6 (human pulmonary carcinoma) and SNU-601 (human gastric carcinoma) cells than from seeds. EtOAc extract showed the highest antiproliferative activity in both sprouts and seeds, followed by n-hexane extraction. During sprouting of mungbean, all the studied components significantly increased. In conclusion, the extracts of sprouts are more effective than from seeds and could be a potential source of antioxidants linked with health benefits.

Immunostimolatory activities of Vigna mungo L. extract in male Sprague-Dawley rats

Vigna mungo L. (Fabaceae) is a popular food legume used in the traditional Indian system of medicine for the treatment of a variety of disease conditions. The objective of the study was to evaluate any immunostimulatory activities of the extract of V. mungo seeds in an animal model. The induction of any immunostimulatory effects were evaluated using measures of sheep red blood cells (SRBC)-induced humoral antibody titer, SRBC-induced delayed-type hypersensitivity (DTH), neutrophil adhesion, and in vivo phagocytosis (via the carbon clearance method) after host treatment with the extract. The results here indicated that primary and secondary antibody titers in the rats were significantly increased by treatment with the V. mungo extract as compared with those noted among rats in a control group. Increases in DTH response, the percentage (%) neutrophil adhesion, and in situ phagocytosis were also observed after treatment with the extract. We summarize that the apparent immunostimulatory effect of the V. mungo seed extract might be attributed to an augmentation of humoral and cell-mediated responses, phagocytosis, and hematopoiesis in the treated rats. The findings in this study suggest that V. mungo seed extract possesses profound immunostimulatory activities. Whether such outcomes are also evidenced by consumption of the intact seeds themselves, as is most likely to be the case with humans, remains to be determined. Nonetheless, the present study provides evidence that could help explain how the traditional use of V. mungo has been successful in the treatment of various disorders in humans.

Antihyperlipidemic activity of Clitoria ternatea and Vigna mungo in rats

CONTEXT

Hyperlipidemia is one of the major risk factors for atherosclerosis and cardiovascular diseases. Some plants are effective in controlling hyperlipidemia.

OBJECTIVE

To investigate the anti-hyperlipidemic effect of Clitoria ternatea L. and Vigna mungo L. (Fabaceae) on experimentally induced hyperlipidemia in rats.

MATERIALS AND METHODS

The poloxamer 407-induced acute hyperlipidemia and diet-induced hyperlipidemia models were used for this investigation.

RESULTS

Oral administration of the hydroalcoholic extract of the roots and seeds of C. ternatea and the hydroalcoholic extract of the seeds of V. mungo resulted in a significant (p < 0.05) reduction of serum total cholesterol, triglycerides, very low-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels. The atherogenic index and the HDL/LDL ratio were also normalized after treatment in diet-induced hyperlipidemic rats. The effects were compared with atorvastatin (50 mg/kg, p.o.) and gemfibrozil (50 mg/kg, p.o.), reference standards.

DISCUSSION

The cholesterol-lowering effect of C. ternatea might be attributed to increased biliary excretion and decreased absorption of dietary cholesterol. The cholesterol-lowering effects of V. mungo seeds might be because of decreased HMG-CoA reductase activity, increased biliary excretion, and decreased absorption of dietary cholesterol. Additionally, they improved natural antioxidant defense mechanisms.

CONCLUSION

The findings of the investigation suggest that C. ternatea and V. mungo have significant antihyperlipidemic action against experimentally-induced hyperlipidemia.

Antioxidant assays for plant and food components

Recently, research on natural antioxidants has become increasingly active in various fields. Accordingly, numerous articles on natural antioxidants, including polyphenols, flavonoids, vitamins, and volatile chemicals, have been published. Assays developed to evaluate the antioxidant activity of plants and food constituents vary. Therefore, to investigate the antioxidant activity of chemical(s), choosing an adequate assay based on the chemical(s) of interest is critical. There are two general types of assays widely used for different antioxidant studies. One is an assay associated with lipid peroxidations, including the thiobarbituric acid assay (TBA), malonaldehyde/high-performance liquid chromatography (MA/HPLC) assay, malonaldehyde/gas chromatography (MA/GC) assay, beta-carotene bleaching assay, and conjugated diene assay. Other assays are associated with electron or radical scavenging, including the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, ferric reducing/antioxidant power (FRAP) assay, ferrous oxidation-xylenol orange (FOX) assay, ferric thiocyanate (FTC) assay, and aldehyde/carboxylic acid (ACA) assay. In this review, assays used recently were selected for extended discussion, including discussion of the mechanisms underlying each assay and its application to various plants and foods.

A novel compound, maltolyl p-coumarate, attenuates cognitive deficits and shows neuroprotective effects in vitro and in vivo dementia models

To develop a novel and effective drug that could enhance cognitive function and neuroprotection, we newly synthesized maltolyl p-coumarate by the esterification of maltol and p-coumaric acid. In the present study, we investigated whether maltolyl p-coumarate could improve cognitive decline in scopolamine-injected rats and in amyloid beta peptide(1-42)-infused rats. Maltolyl p-coumarate was found to attenuate cognitive deficits in both rat models using passive avoidance test and to reduce apoptotic cell death observed in the hippocampus of the amyloid beta peptide(1-42)-infused rats. We also examined the neuroprotective effects of maltolyl p-coumarate in vitro using SH-SY5Y cells. Cells were pretreated with maltolyl p-coumarate, before exposed to amyloid beta peptide(1-42), glutamate or H2O2. We found that maltolyl p-coumarate significantly decreased apoptotic cell death and reduced reactive oxygen species, cytochrome c release, and caspase 3 activation. Taking these in vitro and in vivo results together, our study suggests that maltolyl p-coumarate is a potentially effective candidate against Alzheimer's disease that is characterized by wide spread neuronal death and progressive decline of cognitive function.

Chemical composition of the volatile extract and antioxidant activities of the volatile and nonvolatile extracts of Egyptian corn silk (Zea mays L.)

A total of 36 compounds, which comprised 99.4% of the extract, were identified by gas chromatography and mass spectrometry (GC-MS) in the volatile dichloromethane extract obtained from Egyptian corn silk. The main constituents of the volatile extract were cis-alpha-terpineol (24.22%), 6,11-oxidoacor-4-ene (18.06%), citronellol (16.18%), trans-pinocamphone (5.86%), eugenol (4.37%), neo-iso-3-thujanol (2.59%), and cis-sabinene hydrate (2.28%). Dried Egyptian corn silk was also directly extracted with petroleum ether, ethanol, and water. All extracts from solvent extraction and the volatile extract described above exhibited clear antioxidant activities at levels of 50-400 microg/mL in the 2,2-diphenyl-1-picrylhydrazyl (DPPH)/linoleic acid assay. The ethanol extract inhibited DPPH activity by 84% at a level of 400 microg/mL. All samples tested via the beta-carotene bleaching assay also exhibited satisfactory antioxidant activity with clear dose responses. This study indicates that corn silk could be used to produce novel natural antioxidants as well as a flavoring agent in various food products.

Cell-cell communication in the plant pathogen Agrobacterium tumefaciens

The plant pathogen Agrobacterium tumefaciens induces the formation of crown gall tumours at wound sites on host plants by directly transforming plant cells. This disease strategy benefits the bacteria as the infected plant tissue produces novel nutrients, called opines, that the colonizing bacteria can use as nutrients. Almost all of the genes that are required for virulence, and all of the opine uptake and utilization genes, are carried on large tumour-inducing (Ti) plasmids. The observation more than 25 years ago that specific opines are required for Ti plasmid conjugal transfer led to the discovery of a cell-cell signalling system on these plasmids that is similar to the LuxR-LuxI system first described in Vibrio fischeri. All Ti plasmids that have been described to date carry a functional LuxI-type N-acylhomoserine lactone synthase (TraI), and a LuxR-type signal receptor and transcriptional regulator called TraR. The traR genes are expressed only in the presence of specific opines called conjugal opines. The TraR-TraI system provides an important model for LuxR-LuxI-type systems, especially those found in the agriculturally important Rhizobiaceae family. In this review, we discuss current advances in the biochemistry and structural biology of the TraR-TraI system.

Increase in the free radical scavenging activity of ginseng by heat-processing

To investigate whether or not the radical scavenging activity of ginseng is enhanced by heat processing, we evaluated the scavenging effects of white ginseng (WG), red ginseng (RG, steamed ginseng at 98-100 degrees C) and sun ginseng (SG, steamed ginseng at 120 degrees C) on nitric oxide, superoxide (O2-), hydroxyl (*OH) radicals and peroxynitrite (ONOO-). Heat-treated ginseng (RG and SG) showed better O2-, ONOO- and *OH-scavenging activities than WG. In particular, the radical scavenging activities of SG were stronger than those of RG. Furthermore, we evaluated the radical scavenging activities of maltol, salicylic acid, vanillic acid and p-coumaric acid, known as principal antioxidant components of ginseng, in WG, RG and SG, and also investigated their contents. Of the tested compounds, maltol, vanillic acid and p-coumaric acid exhibited ONOO(-)-scavenging activity. In addition, maltol and p-coumaric acid showed strong *OH-scavenging activity. Moreover, the content of maltol was remarkably increased in a temperature-dependent manner by heat processing, implying that maltol was closely related to the radical scavenging activity of heat-processed ginseng. These findings indicate that SG may act as a free radical scavenger and protect against damage caused by oxidative stress related with these radicals.

Protective effect of Phyllanthus fraternus against allyl alcohol-induced oxidative stress in liver mitochondria

The effect of administration of allyl alcohol on the oxidative stress and the protective effect due to administration of an aqueous extract of Phyllanthus fraternus against allyl alcohol-induced damage in liver mitochondria were studied. When rats were treated with allyl alcohol, the rate of mitochondrial respiration was decreased significantly with both NAD(+)- and FAD-linked substrates. The respiratory control ratio, an index of membrane integrity and the P/O ratio, a measure of phosphorylation efficiency also decreased significantly. There was a significant increase in the lipid peroxide level and the protein carbonyl content. A significant decrease was observed in the total sulphydryl groups and a significant increase in the generation of superoxide radicals. Administration of rats with an aqueous extract of Phyllanthus fraternus (100 mg/kg) prior to allyl alcohol administration showed protection of 72, 40 and 80% using glutamate+malate (NADH oxidation) and 77, 54 and 20% using succinate as substrate on state 3, RCR and P/O ratio, respectively. The protection on lipid peroxide level was 88 and 91% in homogenate and mitochondria, respectively. In case of protein carbonyls, total sulphydryl groups and on the generation of superoxide radicals the protection was 99, 59 and 53%, respectively.

Inhibitory effects of volatile antioxidants found in various beans on malonaldehyde formation in horse blood plasma

The inhibitory effect of aroma extracts isolated from dried soybeans, mung beans, kidney beans, and azuki beans on malonaldehyde (MA) formation from horse blood plasma oxidized with Fenton's reagent was determined by gas chromatography (GC) coupled with nitrogen-phosphorus detector (NPD). Aroma chemicals such as maltol, eugenol, benzyl alcohol, 1-octen-3-ol, butyrolactone, and 1-methyl-2-pyrrolidone, found in the aroma extracts of beans, were also examined for their inhibitory effect on the same system. Among the four aroma extracts tested, the aroma extract of soybeans exhibited the strongest antioxidant activity. Extracts of soybeans, mung beans, azuki beans, and kidney beans inhibited MA formation by 58%, 47%, 40%, and 23%, respectively, at the level of 400 microg/mL, whereas, alpha-tocopherol and BHT inhibited MA formation by 52% and 70%, respectively, at the same level. Among the tested aroma chemicals, the antioxidant activity decreased in the following order: eugenol>maltol>1-octen-3-ol>benzyl alcohol>butyrolactone>1-methyl-2-pyrrolidone.

The assimilation of gamma-butyrolactone in Agrobacterium tumefaciens C58 interferes with the accumulation of the N-acyl-homoserine lactone signal

Agrobacterium tumefaciens C58 communicates using N-acyl-homoserine lactones (acyl-HSL) and contains two lactonase-encoding genes, attM and aiiB, the products of which are capable of inactivating the acyl-HSL signal. In A. tumefaciens A6, the expression of the attKLM operon is controlled by the transcriptional repressor encoded by an adjacent gene, attJ. An attJ::Tn5 mutant does not accumulate acyl-HSL because of the constitutive expression of the lactonase AttM, the activity of which inactivates acyl-HSL. In this work, the attKLM operon of A. tumefaciens C58 was shown to be involved in an assimilative pathway of gamma-butyrolactone (GBL), gamma-hydroxybutyrate (GHB), and succinate semialdehyde (SSA), in which AttM and AttL are key enzymes for GBL and GHB assimilation. The expression of the attKLM promoter was activated in the presence of GBL, GHB, and SSA. Under these conditions, A. tumefaciens C58 did not accumulate the acyl-HSL that it naturally synthesizes, and also became able to inactivate exogenous acyl-HSL signals. Therefore, in A. tumefaciens C58, the assimilative pathway of gamma-butyrolactone interferes with the acyl-HSL signaling.

Ability of eugenol to reduce tongue edema induced by Dieffenbachia picta Schott in mice

Dieffenbachia picta Schott (Araceae), known in Brazil as "comigo-ninguém-pode" is an ornamental plant with toxic properties. Its juice, when chewed, causes a painful edema of the oral mucous membranes, buccal ulcerations and tongue hypertrophy. This acute inflammation sometimes becomes severe enough to produce glottis obstruction, respiratory compromise and death. Eugenol (4-alil-2-metoxiphenol), the essential oil extracted from Caryophyllus aromaticus (Myrtaceae) is widely used in odontology. In this study, our objective was to standardize, in mice, a measurable methodology for the tongue edema induced by the topical application of the D. picta stem juice; evaluate the effects of eugenol in this model and compare the results with emergency treatment used in hospitals. Our results show that in spite of a small increase in edema a few minutes after administration, emergency treatment reduced by 70% the overall edema. When compared with the combination of the above drugs, eugenol, even at the smallest dose of 5 microg/kg, regardless of the chosen administration route, or the moment the treatment began, presents better results in the reduction and inhibition of the tongue edema induced by the D. picta juice.

Fenólicos totais e atividade antioxidante do extrato aquoso de broto de feijão-mungo (Vigna radiata L.)

OBJETIVO: Considerando a importância dos compostos fenólicos em alimentos e que o broto de feijão-mungo vem sendo incluído na culinária brasileira, este estudo teve como objetivo quantificar o teor de fenólicos totais deste vegetal e avaliar a ação antioxidante do seu extrato aquoso. MÉTODOS: Os compostos fenólicos foram extraídos por quatro sistemas de solventes e dois métodos de extração, os quais foram diferenciados no tempo (2 e 1h) e número de extrações (2 e 3 extrações). Os fenólicos totais dos extratos foram quantificados por método espectrofotométrico. RESULTADOS: Os extratos obtidos com água à temperatura ambiente (28ºC), nos dois métodos de extração, foram os que apresentaram maior quantidade de fenólicos totais, sem contudo apresentar diferença significativa entre eles. O método II, que consistiu de três extrações em 1h, pode ser considerado o melhor por ter utilizado menor tempo de extração. O extrato aquoso em sistema modelo b-caroteno/ácido linoléico exibiu ação antioxidante (48,07% de inibição da oxidação), entretanto foi inferior ao padrão BHT. CONCLUSÃO: O broto de feijão-mungo possui considerável quantidade de fenólicos totais, compostos responsáveis por sua ação antioxidante, cujo consumo pode proporcionar efeitos benéficos à saúde.

Screening of medicinal plant extracts for antioxidant activity

The methanol extracts of nine medicinal plants traditionally used in Chinese medicine were screened for antioxidant activity versus resveratrol, which has been shown to protect cells from oxidative damage [Toxicol. Lett. 102 (1998) 5]. Most of the plant extracts used in this study inhibited the H(2)O(2)-induced apoptosis of Chinese hamster lung fibroblast (V79-4) cells. The extracts of Areca catechu var. dulcissima, Paeonia suffruticosa, Alpinia officinarum, Glycyrrhiza uralensis and Cinnamomun cassia strongly enhanced viability against H(2)O(2)-induced oxidative damage in V79-4 cells. Relatively high levels of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were detected in extracts of Areca catechu var. dulcissima, Paeonia suffruticosa and Cinnamomun cassia (IC(50) < 6.0 microg/ml). The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were dose-dependently enhanced in V79-4 cells treated with most of the plant extracts. The extracts of Areca catechu var. dulcissima showed higher antioxidant activity than resveratrol in all experiments. These results suggest that the plant extracts prevent oxidative damage in normal cells probably because of their antioxidant characteristics.

Inhibition of malonaldehyde formation from blood plasma oxidation by aroma extracts and aroma components isolated from clove and eucalyptus

The inhibitory effect of aroma extracts isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry] and eucalyptus leaves (Eucalyptus polyanthemos Schauer) on malonaldehyde (MA) formation from horse blood plasma oxidized with Fenton's reagent was determined by gas chromatography. Aroma chemicals such as eugenol, thymol and benzyl alcohol, identified in the aroma extracts, were examined for their inhibitory effect on the same system. Between the two aroma extracts tested, clove exhibited the most potent antioxidant activities. Extracts of eucalyptus and clove inhibited MA formation by 23 and 48%, respectively, at the level of 400 microg/ml, whereas, alpha-tocopherol and BHT inhibited MA formation by 52 and 70%, respectively, at the same level. Eugenol, thymol and benzyl alcohol inhibited MA formation by 57, 43 and 32%, respectively, at the level of 400 microg/ml.