Antioxidative and Antigenotoxic Effects of Garlic (<Emphasis Type="Italic">Allium sativum</Emphasis> L.) Prepared by Different Processing Methods

This study describes the antioxidant activities and antigenotoxic effects of garlic extracts prepared by different processing methods. Aged-garlic extract (AGE) showed a significantly higher total phenolic content (562.6 ± 1.92 mg/100 g garlic acid equivalents) than those of raw garlic extract (RGE) or heated garlic extract (HGE). The SC₅₀ for DPPH RSA in HGE was significantly the highest at 2.1 mg/ml. The SC₅₀ for SOD-like activity in garlic extracts was, in decreasing order, RGE (7.3 mg/ml) > AGE (8.5 mg/ml) > HGE (9.2 mg /ml). The ED₅₀ of AGE was the highest (19.3 μg/ml) regarding H₂O₂ induced DNA damage and its inhibition rate was 70.8%. The ED₅₀ of RGE for 4-hydroxynonenal (a lipid peroxidation product) induced DNA damage was 38.6 μg/ml, followed by AGE > HGE. Although the heat treatment of garlic tended to decrease the TPC and SOD-like activity and increased DPPH RSA, garlic, in general, has significant antioxidant activity and protective effects against oxidative DNA damage regardless of processing method.     

Antioxidative and Anticancer Activity of Extracts of Cherry (<Emphasis Type="Italic">Prunus serrulata</Emphasis> var. <Emphasis Type="Italic">spontanea</Emphasis>) Blossoms

Organic solvent (methanol, ethanol, and acetone) extracts and water extracts of cherry (Prunus serrulata var. spontanea) blossoms were prepared, and antioxidant activities of the extracts were evaluated. Methanolic CBE (100 μg/ml) showed the highest total phenol content (104.30 μM), radical scavenging activity (34.2%), and reducing power (0.391). The effect of CBE on DNA damage induced by H₂O₂ in human leukocytes was evaluated by Comet assay. All CBE was a potent dose dependent inhibitor of DNA damage induced by 200 μM of H₂O₂, methanolic CBE showed the most strong inhibition activity. The methanolic CBE of 500 μg/ml showed 38.8% inhibition against growth of human colon cancer cell line HT-29. These results indicated that cherry blossoms could provide valuable bioactive materials.     

Inhibitory Effects of Rosemary Extracts, Carnosic Acid and Rosmarinic Acid on the Growth of Various Human Cancer Cell Lines

The leaves of Rosmarinus officinalis harvested from three different locations of Turkey were extracted by both methanolic and supercritical CO₂ extraction. Subsequently, six extracts and the active compounds, carnosic acid, and rosmarinic acid were applied to various human cancer cell lines including NCI-H82 (human, small cell lung, carcinoma), DU-145 (human, prostate, carcinoma), Hep-3B (human, black, liver, carcinoma, hepatocellular), K-562 (human chronic myeloid leukemia), MCF-7 (human, breast, adenocarcinoma), PC-3 (human, prostate, adenocarcinoma) and MDA-MB-231 (human, breast, adenocarcinoma) by MTT assay. Supercritical CO₂ extracts had superior antiproliferative effect compared to the soxhlet extracts. Although the extracts exhibited various cytotoxic effects against different cell lines, comparatively low IC₅₀ values ranging between 12.50 and 47.55 μg/ml were attained against K-562, being the most sensitive cell line. Moreover, carnosic acid caused the lowest cell viability with values ranging from 13 to 30 % at a concentration of 19 μM after 48 h of treatments, resulting in superior antiproliferative effect. Rosemary extract is a potential candidate to be included in the anti-cancer diet with pre-determined doses avoiding toxicity.     

Antioxidant and Antiproliferative Activity of <Emphasis Type="Italic">Diospyros lotus</Emphasis> L. Extract and Isolated Compounds

The object of the study was to determine the chemical composition of Diospyros lotus L. extract and their antioxidant and antiproliferative properties. Eight compounds were isolated from D. lotus and identified as gallic acid, methylgallate, ellagic acid, kaempferol, quercetin, myricetin, myricetin 3-O-β-glucuronide, and myricetin-3-O-α-rhamnoside. D. lotus extract tested in different in vitro systems (DPPH, ABTS, FRAP, and Fe²⁺ chelating activity assay) showed significant antioxidant activity. The potential antiproliferative properties of D. lotus extract and isolated compounds against nine human cancer cell lines such as COR-L23, CaCo-2, C32, ACHN, A375, A549, Huh-7D12, MCF-7, and LNCaP were investigated in vitro by SRB assay. D. lotus extract demonstrated the highest inhibitory activity against COR-L23 with an IC₅₀ value of 12.2 μg/ml. Among identified hydrolysable tannins, ellagic acid evidenced strong antiproliferative activity against both C32 and A375 cells with IC₅₀ values of 0.8 and 4.1 μg/ml, respectively. Interesting results were observed, also, with gallic acid that showed the highest cytotoxic activity against CaCo-2 (IC₅₀ 2.6 μg/ml). Overall, the results of this study suggest that D. lotus displays a good antioxidant activity and has antiproliferative effects. Both activities are related to identified phenolic compounds.     

Inhibitory Activity of Cinnamon Bark Species and their Combination Effect with Acarbose against Intestinal α-glucosidase and Pancreatic α-amylase

Inhibition of α-glucosidase and pancreatic α-amylase is one of the therapeutic approaches for delaying carbohydrate digestion, resulting in reduced postprandial glucose. The aim of this study was to evaluate the phytochemical analysis and the inhibitory effect of various cinnamon bark species against intestinal α-glucosidase and pancreatic α-amylase. The results showed that the content of total phenolic, flavonoid, and condensed tannin ranged from 0.17 to 0.21 g gallic acid equivalent/g extract, from 48.85 to 65.52 mg quercetin equivalent/g extract, and from 0.12 to 0.15 g catechin equivalent/g extract, respectively. The HPLC fingerprints of each cinnamon species were established. Among cinnamon species, Thai cinnamon extract was the most potent inhibitor against the intestinal maltase with the IC₅₀ values of 0.58 ± 0.01 mg/ml. The findings also showed that Ceylon cinnamon was the most effective intestinal sucrase and pancreatic α-amylase inhibitor with the IC₅₀ values of 0.42 ± 0.02 and 1.23 ± 0.02 mg/ml, respectively. In addition, cinnamon extracts produced additive inhibition against intestinal α-glucosidase and pancreatic α-amylase when combined with acarbose. These results suggest that cinnamon bark extracts may be potentially useful for the control of postprandial glucose in diabetic patients through inhibition of intestinal α-glucosidase and pancreatic α-amylase.     

Antioxidative and Antigenotoxic Activity of Extracts from Cosmos (Cosmos bipinnatus) Flowers

The Cosmos bipinnatus has been used in a traditional herbal remedy for various diseases such as jaundice, intermittent fever, and splenomegaly. The present study describes the preliminary evaluation of antioxidant activities and antigenotoxic effect of Cosmos bipinnatus flowers according to four different colors (white, pink, orange, and violet). The antioxidants properties were evaluated by determining TPC, DPPH RSA, ABTS RSA, and RP. The highest TPC of methanolic CFE (at concentration of 1 mg/ml) showed in violet colored CF (1,013 μM), and IC₅₀ of DPPH RSA, ABTS RSA, and RP were also the lowest in violet colored CFE with values of 0.61, 1.48, and 0.82 mg/ml, respectively. The antigenotoxic effect of the CFE on DNA damage induced by H₂O₂ in human leukocytes was evaluated by Comet assay. Pretreatments with CFE produced significant reductions in oxidative DNA damage at the concentration of 500 μg/ml, except for violet colored CFE. The ED₅₀ value of white colored CFE has shown the highest inhibition (0.40 mg/ml) on H₂O₂ induced DNA damage, followed by orange > pink > violet color. These results suggested that Cosmos bipinnatus has significant antioxidant activity and protective effect against oxidative DNA damage.     

Antioxidant Capacity and Phenolics Content of Apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) Kernel as a Function of Genotype

Fourteen apricot genotypes grown under similar cultural practices in Trans-Himalayan Ladakh region were studied to find out the influence of genotype on antioxidant capacity and total phenolic content (TPC) of apricot kernel. The kernels were found to be rich in TPC ranging from 92.2 to 162.1 mg gallic acid equivalent/100 g. The free radical-scavenging activity in terms of inhibitory concentration (IC₅₀) ranged from 43.8 to 123.4 mg/ml and ferric reducing antioxidant potential (FRAP) from 154.1 to 243.6 FeSO₄.7H₂O μg/ml. A variation of 1–1.7 fold in total phenolic content, 1–2.8 fold in IC₅₀ by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and 1–1.6 fold in ferric reducing antioxidant potential among the examined kernels underlines the important role played by genetic background for determining the phenolic content and antioxidant potential of apricot kernel. A positive significant correlation between TPC and FRAP (r = 0.671) was found. No significant correlation was found between TPC and IC₅₀; FRAP and IC₅₀; TPC and physical properties of kernel. Principal component analysis demonstrated that genotypic effect is more pronounced towards TPC and total antioxidant capacity (TAC) content in apricot kernel while the contribution of seed and kernel physical properties are not highly significant.     

White Tea (<Emphasis Type="Italic">Camellia sinensis</Emphasis> Kuntze) Exerts Neuroprotection against Hydrogen Peroxide-Induced Toxicity in PC12 Cells

Tea is a popular beverage whose consumption is associated with prevention of certain disorders. The objective of the study was to investigate the potential neuroprotective effect of white tea extract (WTE) on hydrogen peroxide induced toxicity in PC12 cells. Cells were treated with various doses of WTE (10–250 μg/ml) before exposition to 250 μM hydrogen peroxide and cell survival was determined through the MTT and LDH assays. Oxidative stress was quantified in the cells after treatments as intracellular reactive oxygen species (ROS) production and the antioxidant activity of the extract was assessed in a cell free system in terms of free radical scavenging capacity. Results showed that WTE has a significant protective effect in the PC12 cell line against hydrogen peroxide as cell survival was significantly superior in WTE-treated cells compared to hydrogen peroxide-treated cells. A reduction on intracellular oxidative stress as well as radical scavenging properties were produced by WTE. Results suggest that WTE protects PC12 cells against H₂O₂-induced toxicity, and that an antioxidant mechanism through ROS scavenging may be in part responsible for cells neuroprotection.     

Insulin Secretagogue,Alpha-glucosidase and Antioxidant Activity of Some Selected Spices in Streptozotocin-induced Diabetic Rats

Spices are extensively used to enhance the taste and flavor of foods and are known to possess several medicinal properties. Myristica fragrans, Parmelia perlata, Illicium verum, Trachyspermum copticum and Myristica malabarica, the commonly used spices in India were assessed for antidiabetic activity in streptozotocin induced diabetic rats. In the in vitro insulin secretion studies on isolated islets of Langerhans, M. fragrans, T. copticum and M. malabarica showed dose dependent insulin secretion. At 1 mg/ml, P. perlata showed significant in vitro alpha-glucosidase inhibitory activity with IC₅₀ value of 0.14 mg/ml followed by M. malabarica (0.64 mg/ml), I. verum (0.67 mg/ml), M. fragrans (0.85 mg/ml) and T. copticum (0.92 mg/ml). The DPPH free radical scavenging activity of the extracts at a concentration of 1 mg/ml was as M. malabarica (90.45%), M. fragrans (89.89%), I. verum (87.22%), P. perlata (76.70%) and T. copticum (38.14%). P. perlata showed the highest phenolic content (i.e., 118.5 mg gallic acid equivalents/g) followed by M. malabarica (84.13 mg gallic acid equivalents/g). M. malabarica showed the highest flavonoid content (i.e., 38.35 mg quercetin equivalents/g). Regular use of these spices may prevent postprandial rise in glucose levels through inhibition of intestinal alpha-glucosidase and may maintain blood glucose level through insulin secretagogue action.     

Antihyperglycemic,Antioxidant and Antiglycation Activities of Mulberry Leaf Extract in Streptozotocin-Induced Chronic Diabetic Rats

In Thailand, beverages containing mulberry leaf (Morus alba L.) are believed to promote good health, especially in people with diabetes. We examined the effects of long-term administration of an ethanolic extract of mulberry leaf (MA) on blood glucose, oxidative damage, and glycation in streptozotocin-induced diabetic rats. Daily administration of 1 g/kg MA for six weeks decreased blood glucose by 22%, which was comparable to the effect of 4 U/kg insulin. Lipid peroxidation, measured as malondialdehyde and lipid hydroperoxide concentrations (3.50 ± 0.33 and 3.76 ± 0.18 μM, respectively) decreased significantly (P < 0.05) compared to nontreated control diabetic rats (8.19 ± 0.45 and 7.50 ± 0.46 μM, respectively). Hemoglobin A_1C, a biomarker for chronic exposure to high concentration of glucose, was also significantly decreased in the MA-treated group (6.78 ± 0.30%) in comparison to untreated group (9.02 ± 0.30%). The IC₅₀ of in vitro antiglycation and free radical scavenging activities of MA were 16.4 ± 5.6 μg/ml and 61.7 ± 2.1 μg/ml, respectively. These findings support that long-term administration of MA has antihyperglycemic, antioxidant and antiglycation effects in chronic diabetic rats, which may be beneficial as food supplement for diabetics.     

Antioxidant activity and phenolic content of chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark extracts

Chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark, waste products of the food and wood industries, respectively, were analysed as potential sources of antioxidant compounds. The extraction yield, the antioxidant activity and total phenols content of the extracts were greater in chestnut shell than in eucalyptus bark for most of the extraction conditions essayed. Extraction of chestnut shell with a 2.5% Na₂SO₃ aqueous solution led to the highest extraction yield, 25.6%, total phenols, 13.4 g gallic acid equivalent/100 g oven-dried shell, and FRAP antioxidant activity, 80.7 mmol ascorbic acid equivalent/100 g oven-dried shell. Extraction with methanol:water (50:50, v/v) provided the best results for eucalyptus bark. The antioxidant activity and the total phenols content of the extracts had a positive linear correlation. FTIR spectroscopy confirmed the higher content of phenolic compounds in chestnut shell extracts compared to eucalyptus bark extracts. Chestnut shell extracts were characterized by the presence of high molecular weight species whereas lower molecular weight species were predominant in eucalyptus bark extracts.     

Studies on Indian Green Leafy Vegetables for Their Antioxidant Activity

To identify the potential of green leafy vegetables (GLV) as antioxidants, methanolic extracts of Amaranthus sp., Centella asiatica, Murraya koenigii and Trigonella foenum graecum were studied for their antioxidant activity in different systems at multiple concentrations. Total antioxidant activity assessed by phosphomolybdenum method, free radical scavenging activity by 1,1-diphenly-2-picryl hydrazyl (DPPH), reducing power and ferrous ion chelating activity were determined. The GLV were analyzed for ascorbic acid, total and β-carotene and total polyphenol contents. The ascorbic acid, total carotene, β-carotene and total phenolic content (tannic acid equivalents) of the GLV ranged between 15.18–101.36, 34.78–64.51, 4.23–8.84 and 150.0–387.50 mg/100 g GLV, respectively. The extracts were found to have significantly different levels of antioxidant activities in the systems tested. The total antioxidant activity was highest in Murraya koenigii (2,691.78 μmol of ascorbic acid/g sample) and least in Centella asiatica (623.78 μmol of ascorbic acid/g sample). The extract concentration causing 50% inhibition of DPPH (IC₅₀) was determined (M. koenigii < C.asiatica < Amaranthus sp. < T. graecum). The maximum DPPH scavenging activity and reducing power was exhibited by Murraya koenigii. Multiple regression analysis showed that the relationship of total antioxidant activity, free radical scavenging activity, and reducing power with polyphenol and total and β-carotene was highly significant. Paper awarded the Young Scientist Award in Experimental Nutrition at the Young Scientist Award Session of the 39th Annual Meet of the Nutrition Society of India, Hyderabad, India on 15–16th Dec 2007.     

Seasonal Variation of Phenolic Antioxidant-mediated α-glucosidase Inhibition of <Emphasis Type="Italic">Ascophyllum nodosum</Emphasis>

Ascophyllum nodosum is a brown seaweed that grows abundantly in the US Northeast coastal region. This study examined the seasonal variation of A. nodosum in phenolic contents and subsequent antioxidant, α-glucosidase and α-amylase inhibitory activities. A. nodosum was harvested monthly and extracted in hot water and the resulting extracts were spray-dried. The results indicate a clear seasonal variation in terms of phenolic content, with June and July being the highest (36.4 and 37 mg/g, respectively) and May the lowest (21.8 mg/g). The antioxidant activities, in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, correlated with the phenolic contents observed (r = 0.81), with the month of July being the highest (58%) and April the lowest (26%). Similarly in terms of Trolox equivalent, July had the highest activity (15.53 μM) and April and May the lowest (8.40 and 8.27 μM, respectively). α-glucosidase inhibitory activity exhibited a pattern similar to the phenolic contents observed with July having the highest inhibitory activity (IC₇₀ 2.23 μg) and April the lowest (IC₇₀ 26.13 μg), resulting in an inverse correlation between IC₇₀ values and total phenolic content (r = −0.89). Such seasonal variation is believed to be caused by temperature-related stress considering that A. nodosum is a cold water species.     

Functional study of raw and cooked blue maize flour: Starch digestibility,total phenolic content and antioxidant activity

The purpose of this study was to determine the chemical composition and antioxidant capacity of blue maize (BM) (Zea mays L.) flour and to investigate the effects of polyphenol-containing extracts and BM wholegrain flour on starch digestion under uncooked and cooked conditions; commercial white maize flour was used as control. Total phenolic content in BM flour (BMF) (164 ± 14 mg gallic acid/g of dry matter) was higher than white maize (127 ± 7 mg gallic acid/g of dry matter), and the presence of anthocyanins (2.0 ± 0.5 mg cyanidin 3-glucoside/100 g) was detected. Also, an important scavenging activity against ABTS (2,2’-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and ferric reducing power (FRAP) was determined. Extracts of BMF reduced amylase activity (>90% of inhibition). BMF showed higher slowly digestible and resistant starch contents, thus exhibiting lower predicted glycemic index than white maize. Total anthocyanins (r = −0.89 and r = −0.79, p<0.05), antioxidant capacity (r = −0.86 and r = −0.96, p<0.05), total starch (r = 0.99 and 0.92, p<0.05) and resistant starch content (r = −0.99 and r = −0.92, p<0.05) were correlated with pGI for uncooked and cooked flours, respectively. These results indicate the potential use of BMF and its phenolic-rich extract as functional ingredients to develop antioxidant and indigestible carbohydrate-rich foods with potential health benefits.     

Antihyperglycemic, Antihyperlipidemic and Antiglycation Effects of Byrsonima crassifolia Fruit and Seed in Normal and Streptozotocin-Induced Diabetic Rats

The hypoglycemic effects of hexane, chloroform and methanol extracts from fruits and seeds of Byrsonima crassifolia were evaluated by oral administration to normoglycemic and streptozotocin-induced severe diabetic rats (SD). The anti-diabetic effect was examined by blood glucose, triglycerides, lipid peroxidation, total cholesterol levels in the serum, glycogen content of liver and skeletal muscles, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and oxidized glutathione (GSSG) levels. The most active extracts were obtained with hexane. Hexane and chloroform extracts from fruits and seeds of Byrsonima crassifolia increased the levels of SOD, GSH, GSSG and CAT, hepatic glycogen content, glucose-6-phosphatase (G6Pase) and the plasma insulin levels. They also decreased glucokinase (GK) and TBAR (thiobarbituric acid assay). In conclusion, Byrsonima crassifolia possesses significant antihyperglycemic properties after 4 h of a single oral dose. It can also improve hyperlipidemia and hyperinsulinemia in streptozotocin-induced diabetic rats. Both extracts exhibited significant inhibitory activity against AGEs (advanced glycation end products) formation with IC₅₀ values ranging from 94.3 to 138.7 μg/ml. Therefore, B. crassifolia can be considered as a potential safe anti-diabetic agent.     

Antioxidant and Antimutagenic Activities of Mexican Oregano (Lippia graveolens Kunth)

Free essential oil methanolic extracts from three different geographical populations of Lippia graveolens in México were screened for antioxidant and antimutagenic properties by the DPPH and Kado microsuspension assay, respectively. Total phenolic and flavonoid contents as well as HPLC identification and quantification of naringenin and rosmarinic acid were also carried out. In addition, a taxonomical phenetic analysis was performed. The L. graveolens extracts showed varying content of phenols and flavonoids. Significant concentration of rosmarinic acid was found for the first time in the species. All the extracts were capable of scavenging DPPH radicals in a concentration dependent fashion; the IC₅₀ values correlate with the phenolic content. None of the extracts was toxic to TA100 and TA98 strains at the concentrations tested; moreover, the extracts at a concentration equivalent to 200 μg of gallic acid inhibited a 39 and 30% the mutagenicity induced by 4-nitro-o-phenylenediamine and sodium azide, respectively. The results suggest that the Mexican oregano is a source of polar bioactive ingredients for the food industry.     

Comparative Study on the Chemical Composition,Antioxidant Properties and Hypoglycaemic Activities of Two <Emphasis Type="Italic">Capsicum annuum</Emphasis> L. Cultivars (<Emphasis Type="Italic">Acuminatum</Emphasis> small and <Emphasis Type="Italic">Cerasiferum</Emphasis>)

The present study aimed to evaluate for the first time the phenols, flavonoids, carotenoids, capsaicin and dihydrocapsaicin content and the antioxidant and hypoglycemic properties of Capsicum annuum var. acuminatum small and C. annuum var. cerasiferum air-dried fruits. The ethanol extract of C. annuum var. acuminatum small, characterized by the major content of total poliphenols, flavonoids, carotenoids and capsaicinoids, showed the highest radical scavenging activity (IC₅₀ of 152.9 μg/ml). On the contrary, C. annuum var. cerasiferum showed a significant antioxidant activity evaluated by the β-carotene bleaching test (IC₅₀ of 3.1 μg/ml). The lipophilic fraction of both C. annuum var. acuminatum and C. annuum var. cerasiferum exhibited an interesting and selective inhibitory activity against α-amylase (IC₅₀ of 6.9 and 20.1 μg/ml, respectively).     

Folates Stability in Two Types of Rye Breads During Processing and Frozen Storage

High-performance liquid chromatography was used to study the stability of folate vitamers in two types of rye breads after baking and 16 weeks of frozen storage. Bread made using sourdough seeds contained less total folate (74.6 μg/100 g dry basis, expressed as folic acid) than the whole rye flour (79.8 μg/100 g dry basis) and bread leavened only with baker’s yeast (82.8 μg/100 g dry basis). Most importantly, it was generated by a significant decrease in 5-CH₃-H₄folate form. The baking process caused some changes in folate distribution. Storage of breads at -18°C for 2 weeks did not have a significant effect (p < 0.05) on total folates compared to the content directly after baking. After a 5-weeks storage period, a significant decrease (p < 0.05) in the content of total folates was recorded and it dropped on average by 14% for both type of breads. After a longer period of storage (16 weeks), a 25% loss of folates in the bread made with baker’s yeast and a 38% loss in the bread fermented with sourdough seeds was found. Retention of 5-CH₃-H₄folate and 10-HCO-H₂folate forms were much lower in the bread made with a sourdough addition than with baker’s yeast only.     

Polyphenol-Rich Extract of Fenugreek Seeds Protect Erythrocytes from Oxidative Damage

A polyphenol-rich extract from the seeds of fenugreek was evaluated for its protective effect against hydrogen peroxide(H₂O₂)-induced oxidation in normal and diabetic human erythrocytes (RBCs). RBCs, preincubated with increasing amounts of fenugreek seed extract and challenged with H₂O_2, were analyzed for hemolysis and lipid peroxidation. RBCs from diabetic subjects were more susceptible to oxidative hemolysis and lipid peroxidation than those from normal subjects. However preincubation with the polyphenol-rich extract significantly reduced the oxidative modifications in both the groups. The inhibition of lipid peroxidation was concentration-dependent up to 100 l of extract, which contained 0.75mM gallic acid equivalent (GAE) of phenolic compounds. These findings demonstrate the potent antioxidant properties of the fenugreek seeds.