Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1-15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86?μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R?=?0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1–15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86 μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R = 0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

The antioxidant and cytotoxic activities of Sonchus oleraceus L. extracts

This study investigated in vitro antioxidant activity of Sonchus oleraceus L. by extraction solvent, which were examined by reducing power, hydroxyl radical-scavenging activity(HRSA) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. 70% MeOH extract had the greatest reducing power while EtOH extract had the greatest HRSA. The antioxidant activity of S. oleraceus extracts was concentration dependent and its IC₅₀ values ranged from 47.1 to 210.5 µg/ml and IC₅₀ of 70% MeOH, boiling water and 70% EtOH extracts were 47.1, 52.7 and 56.5 µg/ml, respectively. 70% MeOH extract of S. oleraceus contained the greatest amount of both phenolic and flavonoid contents. The extracts tested had greater nitrite scavenging effects at lower pH conditions. The cytotoxic activity showed that EtOH extract had the best activity against the growth of stomach cancer cell. These results suggest that S. oleraceus extract could be used as a potential source of natural antioxidants.     

Carbohydrase inhibition and anti-cancerous and free radical scavenging properties along with DNA and protein protection ability of methanolic root extracts of Rumex crispus

The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for 60℃ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content (211 µg/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC₅₀ = 42.86 (absolute methanol) and 36.91 µg/mL (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in H₂O₂/Fe³⁺/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at 400 µg/mL was observed to be highest (10.2% ± 1.03). Moreover, methanolic RERC inhibited α-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.     

Antioxidant and antidiabetic activities of extracts from Cirsium japonicum roots

This study investigated the antioxidant activity of methanol (MeOH) and water extracts from roots of Cirsium japonicum in vitro. MeOH extract showed a stronger free radical scavenging activity than water extract. However, both of extracts showed a concentration dependent hydroxyl radical scavenging activity, reducing power and metal chelating ability. MeOH extract had greater phenolic and flavonoid contents than water extract. The antidiabetic activity of these two extracts was evaluated by the α-glucosidase inhibition assay. The water extract showed a considerable α-glucosidase inhibitory activity. To our knowledge, this may be the first time to report the antioxidant and antidiabetic activities in Cirsium japonicum roots.     

Chestnut extract induces apoptosis in AGS human gastric cancer cells

In Korea, chestnut production is increasing each year, but consumption is far below production. We investigated the effect of chestnut extracts on antioxidant activity and anticancer effects. Ethanol extracts of raw chestnut (RCE) or chestnut powder (CPE) had dose-dependent superoxide scavenging activity. Viable numbers of MDA-MD-231 human breast cancer cells, DU145 human prostate cancer cells, and AGS human gastric cancer cells decreased by 18, 31, and 69%, respectively, following treatment with 200 µg/mL CPE for 24 hr. CPE at various concentrations (0-200 µg/mL) markedly decreased AGS cell viability and increased apoptotic cell death dose and time dependently. CPE increased the levels of cleaved caspase-8, -7, -3, and poly (ADP-ribose) polymerase in a dose-dependent manner but not cleaved caspase-9. CPE exerted no effects on Bcl-2 and Bax levels. The level of X-linked inhibitor of apoptosis protein decreased within a narrow range following CPE treatment. The levels of Trail, DR4, and Fas-L increased dose-dependently in CPE-treated AGS cells. These results show that CPE decreases growth and induces apoptosis in AGS gastric cancer cells and that activation of the death receptor pathway contributes to CPE-induced apoptosis in AGS cells. In conclusion, CPE had more of an effect on gastric cancer cells than breast or prostate cancer cells, suggesting that chestnuts would have a positive effect against gastric cancer.     

Bioconverted Jeju Hallabong tangor (Citrus kiyomi × ponkan) peel extracts by cytolase enhance antioxidant and anti-inflammatory capacity in RAW 264.7 cells

BACKGROUND/OBJECTIVES

Citrus and its peels have been used in Asian folk medicine due to abundant flavonoids and usage of citrus peels, which are byproducts from juice and/or jam processing, may be a good strategy. Therefore, the aim of this study was to examine antioxidant and anti-inflammatory effects of bioconversion of Jeju Hallabong tangor (Citrus kiyomi × ponkan; CKP) peels with cytolase (CKP-C) in RAW 264.7 cells.

MATERIALS/METHODS

Glycosides of CKP were converted into aglycosides with cytolase treatment. RAW 264.7 cells were pre-treated with 0, 100, or 200 µg/ml of citrus peel extracts for 4 h, followed by stimulation with 1 µg/ml lipopolysaccharide (LPS) for 8 h. Cell viability, DPPH radical scavenging activity, nitric oxide (NO), and prostagladin E₂ (PGE₂) production were examined. Real time-PCR and western immunoblotting assay were performed for detection of mRNA and/or protein expression of pro-inflammatory mediators and cytokines, respectively.

RESULTS

HPLC analysis showed that treatment of CKP with cytolase resulted in decreased flavanone rutinoside forms (narirutin and hesperidin) and increased flavanone aglycoside forms (naringenin and hesperetin). DPPH scavenging activities were observed in a dose-dependent manner for all of the citrus peel extracts and CKP-C was more potent than intact CKP. All of the citrus peel extracts decreased NO production by inducible nitric oxide synthase (iNOS) activity and PGE₂ production by COX-2. Higher dose of CKP and all CKP-C groups significantly decreased mRNA and protein expression of LPS-stimulated iNOS. Only 200 µg/ml of CKP-C markedly decreased mRNA and protein expression of cyclooxygenase-2 in LPS-stimulated RAW 264.7 cells. Both 100 and 200 µg/ml of CKP-C notably inhibited mRNA levels of interleukin-1β (IL-1β) and IL-6, whereas 200 µg/ml CKP-C significantly inhibited mRNA levels of TNF-α.

CONCLUSIONS

This result suggests that bioconversion of citrus peels with cytolase may enrich aglycoside flavanones of citrus peels and provide more potent functional food materials for prevention of chronic diseases attributable to oxidation and inflammation by increasing radical scavenging activity and suppressing pro-inflammatory mediators and cytokines.     

Antioxidant Activities and Total Phenolic Content of Aqueous Extract of Pleurotus ostreatus (Cultivated Oyster Mushroom)

Pleurotus ostreatus better known as oyster mushroom is widely cultivated and consumed as food in Malaysia. The present study aims to assess the antioxidative potential and total phenolic content of P. ostreatus aqueous extract. The antioxidant activities were evaluated against DPPH and ABTS radical-scavenging activity, ferric-reducing antioxidant power (FRAP) and β-carotene-linoleate bleaching assay, and the Folin-Ciocalteu method for total phenolic content (TPC). The DPPH and ABTS radical-scavenging activity was found to be 63.20% and 87.29% respectively; antioxidant activity using FRAP at 1.45 mM FE/100g and β-carotenelinoleate bleaching assay was 83.51%, while the TPC was found to be 798.55 mg GAE/100g. These antioxidant activities were compared to synthetic antioxidant, BHA and ascorbic acid. Ascorbic acid showed highest scavenging effects on DPPH and ABTS radical, followed by P. ostreatus and BHA (at maximum safety limit). The ferric reducing power of P. ostreatus was significantly higher than BHA and ascorbic acid. The antioxidant activity as assessed in β-carotene-linoleate bleaching assay was found to be higher in BHA compared to P. ostreatus. The aqueous extract of P. ostreatus was found to respond differently in antioxidant assays. The antioxidative activity of the aqueous extract of P. ostreatus correlated with its total phenolic content. Generally, the antioxidant activities of P. ostreatus' aqueous extract are comparable to that of BHA and ascorbic acid to a certain extent.     

Phenolic Composition,Antioxidant Activity and Anti-Adipogenic Effect of Hot Water Extract from Safflower (Carthamus tinctorius L.) Seed

This study was to evaluate the phenolic content and composition of Carthamus tinctorius L. seed extract (CSE) and to further assess its antioxidant and anti-adipogenic activities using various radical scavenging systems and 3T3-L1 cells. Our results show that the total phenolic and flavonoid contents of CSE were 126.0 ± 2.4 mg GAE/g and 62.2 ± 1.9 mg QE/g, respectively. The major phenolic compounds in CSE was (−)-epigallocatechin (109.62 mg/g), with a 4-hydroxy benzhydrazide derivative and gallocatechin present at 18.28 mg/g and 17.02 mg/g, respectively. CSE exhibited remarkable radical scavenging activities, FRAP (ferric reducing antioxidant power) and reducing power in a dose-dependent manner. Moreover, the oxygen radical absorbance capacity (ORAC) value of CSE (0.1 mg/mL) was 62.9 ± 4.7 μM TE (trolox equivalent)/g. During adipogenesis, CSE significantly inhibited fat accumulation in 3T3-L1 cells compared with control cells. Overall, these results indicate that CSE might be a valuable source of bioactive compounds that impart functional food and natural antioxidant properties.     

Antioxidant activities of New Zealand-grown tomatoes

The objective of this study was to compare the antioxidant activities, total phenolics, lycopene and ascorbic acid content of four commercial tomato cultivars (Excell, Tradiro, Flavourine and Campari) of New Zealand, grown under similar hydroponic conditions. The mean antioxidant activity of the four cultivars, as measured with the ABTS radical decolourization assay, ranged from 2329 to 3268 micromole TEAC/100 g dry matter (DM) in the hydrophilic extracts and from 178 to 303 micromole TEAC/100 g DM in the lipophilic extracts. The major antioxidant components per 100 g DM were phenolics (343-451 mg gallic acid equivalents in hydrophilic extract and 53-74 mg gallic acid equivalents in lipophilic extract), flavonoids (175-204 mg rutin equivalents), ascorbic acid (153-195 mg) and lycopene (33-54 mg). Ascorbic acid and flavonoids were found to contribute 28-38% and 29-34%, respectively, to the antioxidant activity of the hydrophilic extract of tomatoes. The results showed that the smallest cultivar (Campari) had significantly (P < 0.05) higher antioxidant activities, total phenolics and flavonoids than the larger sized cultivars (Excell, Tradiro and Flavourine). This could be attributed to the significantly (P < 0.05) higher surface area/volume ratio of the small cultivar (0.15) when compared with the large-sized cultivars (0.10-0.12). The tomato cultivar (Flavourine) with a brighter red colour (higher a*/b* value), had a higher lycopene content as well, which suggests that the a*/b* value of tomatoes can be used as an indicator of their lycopene content. The phenolics (r = 0.84**) and flavonoids (r = 0.88**) were significantly related to the antioxidant activity of the hydrophilic extract, which suggests that measurement of total phenolics or flavonoids can be used as indicators of the antioxidant activity of tomatoes.     

Evaluation of antioxidant properties of a new compound, pyrogallol-phloroglucinol-6,6'-bieckol isolated from brown algae, Ecklonia cava

In this study, antioxidant and free radical scavenging activities of the natural antioxidative compound, pyrogallol-phloroglucinol-6,6''-bieckol (PPB) isolated from brown algae, Ecklonia cava was assessed in vitro by measuring the radical scavenging activities (DPPH, alkyl, hydroxyl, and superoxide) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assay. According to the results of these experiments, the scavenging activity PPB against difference radicals was in the following order: DPPH, alkyl, hydroxyl, and superoxide radicals (IC₅₀; 0.90, 2.54, 62.93 and 109.05 µM). The antioxidant activities of PPB were higher than that of the commercial antioxidant, ascorbic acid. Furthermore, PPB effectively inhibited DNA damage induced by H₂O₂. These results suggest that the natural antioxidative compound, PPB, can be used by the natural food industry.     

Comparison of antioxidant capacities of Ganoderma lucidum (Curtis) P. Karst and Funalia trogii (Berk.) Bondartsev & Singer by using different in vitro methods

The aim of the study was to investigate antioxidant activities of Ganoderma lucidum and Funalia trogii. Ethanol and water crude extracts from G. lucidum and F. trogii were investigated for their antioxidant capacity in some different assays, namely, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal chelating activity against ferrous ions, and plasma lipid peroxidation inhibitory. In addition, the amounts of total phenol, ascorbic acid, β-carotene, and lycopene components in the extracts were determined. Among the four mushroom extracts, G. lucidum water extract and G. lucidum ethanol extract showed the highest scavenging activity against DPPH radicals (50% inhibitory concentration?=?0.055?±?0.001?mg/mL). Total phenol was the major antioxidant component found in the mushroom extracts. These results showed that G. lucidum may be used in pharmaceutical applications because of its effective antioxidant properties.     

Anthocyanins in Red Jasmine Rice (Oryza sativa L.) Extracts and Efficacy on Inhibition of Herpes Simplex Virus,Free Radicals and Cancer Cell

Rice is one of the most important food crops in many countries, with nutritional value and health benefits. In this study, the ethanolic and aqueous extracts of red jasmine rice from Chiang Mai, Thailand were examined for their anthocyanins and phenolic contents. The antioxidant and antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), as well as anticancer activity, were investigated. The total anthocyanins content of 708.03 ± 11.56 mg Cy-3-glc equivalent/g extract, determined from the ethanolic extract, was higher than the aqueous extract. However, the aqueous extract showed the highest total phenolic compound of 81.91 ± 0.51 mg GAE/g extract. In addition, the ethanolic extract demonstrated higher antioxidant activity than aqueous extract using DPPH, ABTS, and FRAP assays by 28.91 ± 3.26 mg GAE/g extract, 189.45 ± 11.58 mg 24 TEAC/g extract, and 3292.46 ± 259.64 g FeSO₄/g extract, respectively. In the antiviral assay, it was found that the ethanolic extract of red jasmine rice could inhibit HSV-1 more effectively than HSV-2 when treated before, during, and after the viral attachment on Vero cells, with 50% effective doses of 227.53 ± 2.41, 189.59 ± 7.76, and 192.62 ± 2.40 µg/mL, respectively. The extract also demonstrated the highest reduction of HSV-1 particles at 4 h after treatment and the inhibition of HSV-1 replication. The ethanolic extract exhibited a higher toxicity level than the aqueous extract, as well as the potential to induce DNA fragmentation by intrinsic and extrinsic apoptosis pathways on the Caco-2 cells. These findings suggest that red jasmine rice extract demonstrates nutritional value and biological activity on HSV, free radicals, and cancer cell inhibition.     

Antioxidant activity of selected commercial seaweeds

This study aims to evaluate the antioxidant activity (total antioxidant and free radical scavenging activities) of seaweeds commercially available in the Malaysian supermarket. Four types of seaweeds namely Nori (Porphyra sp.), Kumbu (Laminaria sp.), Wakame (Undaria sp.) and Hijiki (Hijikia sp.) were used in the study. The extracts were prepared with water and ethanol, respectively. The b-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine antioxidant properties of seaweeds by measuring the decrease in absorbance at 470 and 517 nm. In water extract, Kumbu showed the highest total antioxidant activity of 63% compared with other samples. Kumbu, Nori and Hijiki exhibited higher radical scavenging activity than Wakame when extracted with water. Wakame exhibited the highest antioxidant and free radical scavenging activities in ethanolic extract with 58% and EC50 = 0.42 mg/ml respectively. The results of ANOVA analysis show significant differences (p<0.05) in the means of total antioxidant and free radical scavenging activities of the seaweeds. The results showed that processed commercial seaweeds exhibited varying degrees of antioxidant properties.     

Scavenging effects of methanolic extracts of broad beans on free-radical species

This report describes the antioxidant characteristics of methanolic extracts from broad beans (Vicia fava). The methanolic extracts of broad beans (MEBB) exhibited a marked scavenging effect on superoxide. MEBB also exerted scavenging activities on hydrogen peroxide and 1, 1-diphenyl-2-picrylhydrazyl radical. The radical scavenging activity of MEBB was highest when the scavenging effect of MEBB on Superoxide (IC₅₀ = 0.15 mg/ml) was examined. These results suggest that MEBB have effective activities both as a radical scavenger and as a hydrogen donor. The chelating activity of MEBB (0.70 mg/ml) on Fe²⁺ and Cu²⁺ was 31.2% and 28.5%, respectively. The antioxidant effect of MEBB on lipid peroxidation might be attributed to their properties of scavenging free-radical species and their chelating activity on metal ions. The antioxidant activity of MEBB against tert-butyl hydroperoxide (BHP)-induced oxidative stress in WI-38 cells was assessed. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) were measured as indices of oxidative stress. WI-38 cells incubated with 0.1 mM BHP for 2 hr exhibited the increase of SOD, catalase and GSH-Px activities over the control. When the cells incubated in MEBB (45–450 μg/ml) for 18 hr were subjected to a BHP challenge test, SOD activity returned to its control value or lower at all levels tested. When catalase activity was determined, a similar trend occurred except in the cells incubated in 112.5 μ g/ml MEBB. These results imply that MEBB inhibit oxidative stress in WI-38 cells.     

Optimized mixture of hops rho iso-alpha acids-rich extract and acacia proanthocyanidins-rich extract reduces insulin resistance in 3T3-L1 adipocytes and improves glucose and insulin control in db/db mice

Rho iso-alpha acids-rich extract (RIAA) from Humulus lupulus (hops) and proanthocyanidins-rich extracts (PAC) from Acacia nilotica exert anti-inflammatory and anti-diabetic activity in vitro and in vivo. We hypothesized that a combination of these two extracts would exert enhanced effects in vitro on inflammatory markers and insulin signaling, and on nonfasting glucose and insulin in db/db mice. Over 49 tested combinations, RIAA:PAC at 5:1 (6.25 µg/mL) exhibited the greatest reductions in TNFα-stimulated lipolysis and IL-6 release in 3T3-L1 adipocytes, comparable to 5 µg/mL troglitazone. Pretreatment of 3T3-L1 adipocytes with this combination (5 µg/mL) also led to a 3-fold increase in insulin-stimulated glucose uptake that was comparable to 5 µg/mL pioglitazone or 901 µg/mL aspirin. Finally, db/db mice fed with RIAA:PAC at 5:1 (100 mg/kg) for 7 days resulted in 22% decrease in nonfasting glucose and 19% decrease in insulin that was comparable to 0.5 mg/kg rosiglitazone and better than 100 mg/kg metformin. RIAA:PAC mixture may have the potential to be an alternative when conventional therapy is undesirable or ineffective, and future research exploring its long-term clinical application is warranted.     

Radical scavenging, antibacterial, and antiproliferative activities of Melissa officinalis L. extracts

The aromatic herb Melissa officinalis L. can be used as an easily accessible source of natural antioxidants and as a possible food supplement and as a phytochemical. Radical scavenging, antibacterial, and antiproliferative activities of petroleum ether, chloroform, ethyl acetate, n-butanol, and water extracts of M. officinalis L. extracts were investigated. The results of antioxidative activity, obtained by electron spin resonance spectroscopy, confirmed that investigated extracts suppressed the formation of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and lipid peroxyl radicals in all investigated systems in a dose-dependent manner. The maximum DPPH and hydroxyl radical scavenging activities (SA(DPPH) = SA(OH) = 100%) were achieved in the presence of n-butanol extract at concentrations of 0.4 mg/mL and 0.5 mg/mL, respectively. The highest lipid peroxyl scavenging activity (93.20%) was observed at a higher concentration (5 mg/mL) of n-butanol extract in the lipid peroxidation system. The most effective antibacterial activities were expressed by petroleum ether and ethyl acetate extracts on Sarcina lutea. Chloroform extract showed the strongest antiproliferative effect with 50% inhibitory concentration values of 0.09 mg/mL and 0.10 mg/mL for HeLa and MCF-7 cell lines, respectively. The present study demonstrated the high phenolic content and radical scavenging, antibacterial, and antiproliferative activities of extracts of M. officinalis L. originating from Serbia.     

Antioxidant levels and activities of selected seeds of malaysian tropical fruits

The aims of this study are to determine and compare the antioxidant levels and activities (i.e. primary and secondary) between selected seeds of Malaysian tropical fruits - guava (Psidium guajava), mango (Mangifera indica L.) and papaya (Carica papaya L.). Seeds are among byproducts from the processing of fruitsbased products. Instead of discarding seeds as waste, seeds with high potential as antioxidants could be utilised for commercial purposes. Accordingly, the selected seeds of Malaysian tropical fruits were tested in this study for total phenolic content (TPC), free radical scavenging activity by 1, 1- diphenyl-2-picrylhydrazyl (DPPH) assay and metal ion chelating effect by ferrous ion chelating (FIC) assay. Extraction of antioxidant compounds from sample was done with 70% ethanol. TPCs of the seeds were expressed as gallic acid equivalents (GAE) in mg per 100 g fresh seed weight. TPC assay showed that mango seeds had the highest TPC (i.e. 32 ± 0.001 mg GAE) followed by guava seeds (i.e. 20 ± 0.001 mg GAE) and papaya seeds (8 ± 0.003 mg GAE). For DPPH assay, IC50 data showed that mango seed extract scavenged 50% DPPH radicals at the lowest concentration (0.11 ± 0.01 mg/mL) followed by the positive control BHA (0.13 ± 0.01 mg/mL), guava seed extract (0.26 ± 0.01 mg/mL) and papaya seed extract (0.34 ± 0.01 mg/mL). Interestingly, all seed extracts showed higher free radical scavenging activities than BHA after sample concentration of 0.60 mg/mL. However, FIC assay indicated that metal ion chelating effects of all seed extracts were weaker than BHA suggesting that the fruit seeds are not sources of good metal ion chelators. Overall, present results suggest that TPC of the seeds show strong negative correlation with their primary antioxidant activity (r= -0.985, R2= 0.970), and not all compounds in extracts which could scavenge DPPH radicals are good metal ion chelators. Mango seeds relatively showed the highest antioxidant level and primary antioxidant activity followed by guava seeds and papaya seeds.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75?µg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8?µg gallic acid equivalent of phenols was detected in 1?mg WEBP and EEBP.     

The antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts

Antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts were evaluated using various antioxidant measurements, i.e., inhibitory effect on thiobarbituric acid-reactive substances (TBARS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating effect, reducing power effect, and total phenolic compounds. When the extraction solvents n-hexane, chloroform, ethanol, and water were compared, the water extract showed the highest yield in extracted mass. Total phenolic compounds were the highest in the ethanol extract, with 127.4 mg/g. The TBARS inhibition of chloroform and ethanol extracts at 10 mg/mL was 90.9% and 80.9%, respectively. DPPH radical scavenging capacity was more than 90% in all extracts at 1 mg/mL. The chloroform extract exhibited the highest metal ion chelating ability of 69.6% at 10 mg/mL. The reducing power was found to be the highest in the ethanol extract at 10 mg/mL, showing an effect similar to ascorbic acid. Thus, the ethanol extract of S. siliquastrum has potential as a natural antioxidant.