A systematic survey of antioxidant activity of 30 Chinese medicinal plants using the ferric reducing antioxidant power assay

The antioxidant activities and total phenolic contents of 30 Chinese medicinal plants were evaluated using the ferric reducing antioxidant power assay and the Folin–Ciocalteu method, respectively. The Chinese medicinal plants were extracted by the traditional method, boiling in water and also in 80% methanol. A significant and linear correlation coefficient between the antioxidant activity and the total phenolic content was found in both aqueous (R² = 0.7917) and methanol (R² = 0.7584) extracts. Phenolic compounds are thus a major contributor of antioxidant activity. Comparing the extraction efficiency of the two methods, the boiling water method extracted phenolic compounds more efficiently, and antioxidant activity of the extract was higher. It was found that the Chinese medicinal plants Rhodiola sacra Fu, the stem of Polygonum multiflorum Thunb. and the root of P. multiflorum Thunb. possessed the highest antioxidant activities and thus could be potential rich sources of natural antioxidants.     

Hepatoprotective and antioxidant activity of ethanolic extracts of edible lotus (Nelumbo nucifera Gaertn.) leaves

Lotus (Nelumbo nucifera Gaertn.), an aquatic vegetable, is extensively cultivated in eastern Asia, particularly in China. An ethanolic extract of the leaves was studied for its hepatoprotective activity against CCl₄-induced liver toxicity in rats. In vitro and in vivo antioxidant activity was also assessed. The results showed the hepatoprotective activity of lotus leaf extract (LLE) at doses of 300 and 500 mg/kg and in vivo antioxidant activity at 100 mg/kg that was comparable with that of a standard treatment comprising 100 mg/kg of silymarin, a known hepatoprotective drug. These data were supplemented with histopathological studies of rat liver sections. The main flavonoids and phenolic compounds of LLE were analysed by HPLC-DAD-ESI/MS methods. Six of the compounds detected were tentatively characterised, one as catechin glycoside and five as flavonoid glycoside derivatives: miricitrin-3-O-glucoside, hyperin, isoquercitrin, quercetin-3-O-rhamnoside and astragalin.     

Antioxidant and anti-inflammatory properties of taiwanese yam (Dioscorea japonica Thunb. var. pseudojaponica (Hayata) Yamam.) and its reference compounds

Dioscorea japonica Thunb. var. pseudojaponica (DP) is consumed as food and widely used in traditional Chinese medicine in Taiwan. The aims of this study are to investigate the antioxidant and anti-inflammatory effects of ethanol extract of DP (EDP) and its reference compounds. Fingerprint chromatogram from HPLC indicated that EDP contains gallic acid and vanillic acid. EDP was evaluated for its antioxidant effects and LPS-induced nitrite oxide (NO) production in RAW264.7 cells. EDP decreased the LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells. In-vivo anti-inflammatory activities of EDP were assessed in mouse paw oedema induced by λ-carrageenan (Carr). We investigated the antioxidant mechanism of EDP via studies of the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) and the levels of malondialdehyde (MDA) in the oedematous paw. The results showed that EDP might be a natural antioxidant and anti-inflammatory agent.     

Antioxidant and anti-inflammatory properties of Dichondra repens Forst. and its reference compounds

Dichondra repens (DR) is the main constituent in herbal beverages and consumed daily as a nutrition supplement for the liver in Taiwan. This study investigated the antioxidant and anti-inflammatory effects of D. repens ethanol extract (EDR) and its reference compounds ex vivo and in vivo. Fingerprint chromatograms (from HPLC) indicated that EDR contained vanillin, umbelliferone and scopoletin. EDR was evaluated for its antioxidant effects and LPS-induced NO production in RAW 264.7 cells. EDR decreased the LPS-induced NO production and expressions of iNOS and COX-2 in RAW 264.7 cells. In vivo anti-inflammatory activities of EDR were assessed in mouse paw oedema, induced by λ-carrageenan (Carr). We investigate the antioxidant mechanism of EDR via studies of the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the liver and the levels of malondialdehyde (MDA) and nitrite oxide (NO) in the oedematous paw. Serum NO and TNF-α were also measured. EDR exerts anti-inflammatory effects by suppressing TNF-α, NO, and might be related to the decrement of the level of MDA in the oedema paw via increasing the activities of CAT, SOD and GPx in the liver. The results show that EDR might be a natural antioxidant and anti-inflammatory agent.     

The in vitro and in vivo antioxidant properties of seabuckthorn (Hippophae rhamnoides L.) seed oil

The antioxidant capacity of seabuckthorn (Hippophae rhamnoides L.) seed oil was investigated with a number of established in vitro assays and in an in vivo study of carbon tetrachloride (CCl₄)-induced oxidative stress in mice. The results showed that DPPH radical scavenging activity, ferrous ion chelating activity, reducing power and inhibition of lipid peroxidation activity all increased with increasing concentrations of seabuckthorn seed oil. Moreover, the EC₅₀ values of seabuckthorn seed oil from the hydrogen peroxide, superoxide radical, hydroxyl radical scavenging assays were 2.63, 2.16 and 0.77 mg/ml, respectively. In the in vivo study, seabuckthorn seed oil inhibited the toxicity of CCl₄, as seen from the significantly increased activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The GSH content in the liver was also increased, whereas hepatic malondialdehyde was reduced. Taken together, these results clearly indicate that seabuckthorn seed oil has significant potential as a natural antioxidant agent.     

Antioxidant activity of phenolic and phenylethanoid glycosides from Teucrium polium L

In the present study, the chemical composition and antioxidant activities of Teucrium polium L. (Lamiaceae) were assessed. Fractionation of methanol extract obtained from the aerial parts of T. polium yielded one new phenylethanoid glycoside, named poliumoside B, together with four known flavonoids, two iridoid glycosides and a known poliumoside. The structures of all of these compounds were elucidated on the basis of spectroscopic data from 1D and 2D NMR experiments and MS spectral analyses. The antioxidant activities of the crude extracts and of the isolated compounds were evaluated through tests such as DPPH radical-scavenging capability, reducing power, xanthine oxidase inhibitory effect and inhibition of linoleic acid peroxidation. The highest antioxidant activity was found in the n-butanol extract, which also contained active polyphenols, thus suggesting that this plant could be used as a source of natural molecules, to provide safe antioxidant additives and nutraceuticals. The structure–activity relationships of the isolated compounds are also discussed.     

Antioxidant and immunomodulatory activity of selenium exopolysaccharide produced by Lactococcus lactis subsp. lactis

Exopolysaccharide (EPS) was isolated and purified from Lactococcus lactis subsp. Lactis culture broth. Selenium chloride oxide (SeCl₂O) was added to the EPS to synthesize selenium-exopolysaccharide (Se-EPS). The in vitro and in vivo antioxidant and in vivo immunomodulatory activity of EPS and Se-EPS were compared. EPS and Se-EPS scavenged superoxide anions and hydroxyl radicals. They also increased catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, while decreasing malondialdehyde (MDA) levels in serum and in the livers of mice. Se-EPS showed stronger in vitro and in vivo antioxidant activity than were shown by EPS. The in vivo immunoenhancement activity of EPS and Se-EPS induced by cyclophosphamide (CY) treatment in immunosuppressed mice was researched. EPS and Se-EPS treatments increased macrophage phagocytosis, spleen and thymus indices and haemolytic complement activity (HC₅₀). Se-EPS showed stronger immunomodulatory activity than did EPS.     

何首乌中二苯乙烯苷的体外抗氧化研究

从传统抗衰老中药何首乌中提取、分离、纯化得到不同组分:乙醇粗提物、大孔吸附树脂层析样品及二苯乙烯苷晶体,并运用HPLC-MS、NMR、X-衍射对二苯乙烯苷晶体进行了分析鉴定。对照白藜芦醇分别对三组分的抗氧化清除自由基性能进行了测定。包括还原能力、亚油酸体系抗氧化性能以及清除DPPH自由基、清除羟基自由基、清除超氧阴离子能力。结果表明:不同纯度的二苯乙烯苷均具有还原性,抗氧化及清除自由基性能,其中以二苯乙烯苷纯品最强。其半抑制率分别为:DPPHIC508.06μg/ml;羟基自由基IC502.75μg/ml;超氧阴离子IC500.57μg/ml;以上各指标均略高于白藜芦醇。     

Antioxidant activities of malt extract from barley (Hordeum vulgare L.) toward various oxidative stress in vitro and in vivo

The antioxidant activities of malt extract from barley were evaluated by various methods in vitro and in vivo. Scavenging effects on the hydroxyl and superoxide radicals, and protection against reactive oxygen species induced lipid, protein and DNA damage were evaluated. The d-galactose induced mouse aging model was used to evaluate ability of malt extract to behave as an antioxidant in vivo. The extract exhibited high antioxidant activities both in vitro and in vivo, evidenced by its ability to scavenge hydroxyl- and superoxide-radicals, high reducing power, and protection against biological macromolecular oxidative damage. Furthermore, malt extract prevented the decrease of antioxidant enzyme activities, decreased liver and brain malondialodehyde levels and carbonyl content, and improved total antioxidant capability in d-galactose-treated mice. In conclusion, these results demonstrate potential antioxidant activities and antiaging effect of malt, providing scientific support for the empirical use of malt as an antioxidant for diseases caused by reactive oxygen species.     

Fucoxanthin content and antioxidant properties of Undaria pinnatifida

This study investigated the fucoxanthin content of New Zealand (NZ) Undaria pinnatifida harvested from two locations in the Marlborough Sounds, New Zealand across its growing season. Fucoxanthin content and antioxidant properties of processed New Zealand U. pinnatifida and commercial wakame from Japan and Korea were further compared. Results showed that U. pinnatifida harvested from Port Underwood had higher fucoxanthin content in the blade compared to Pelorus Sound. The sporophyll also contained a significant amount of fucoxanthin throughout the harvest season, although lower than in the blade. Two antioxidant measurement methods, DPPH and CUPRAC, were utilised to measure antioxidant activities. Processed NZ U. pinnatifida had a lower fucoxanthin content and antioxidant activity than freeze-dried Undaria. Fucoxanthin content and antioxidant activities of NZ processed U. pinnatifida were not significantly different from other commercial samples from Japan and Korea. In conclusion, U. pinnatifida in New Zealand has a great potential to be a food and nutraceutical resource.     

Phytoconstituents and therapeutic uses of Rheum emodi wall. ex Meissn

Rhubarb (Rheum emodi, family Polygonaceae) has been traditionally used as diuretic, liver stimulant, purgative/cathartic, stomachic, anticholesterolaemic, antitumour, antiseptic and tonic. A number of anthraquinone derivatives including emodin, aloe-emodin, physcion, chrysophanol, rhein, emodin glycoside and chrysophanol glycoside occur as the main chemical constituents. In the past few years, new components such as sulfemodin 8-O-β-d-glucoside, revandchinone-1, revandchinone-2, revandchinone-3, revandchinone-4, 6-methyl-rhein and 6-methyl aloe-emodin have been reported from the same species. Anthraquinone derivatives show evidence of antifungal, anti-microbial, anti-Parkinson’s, anti-proliferative, immuno-enhancing, antiviral and antioxidant activities. This review covers published work on botany, chemistry and therapeutic uses of different components from rhubarb.     

Phenolic profiles of in vivo and in vitro grown Coriandrum sativum L.

Coriandrum sativum L. is a source of a variety of polyphenols and other phytochemicals, related to its high antioxidant activity and to its use for indigestion, rheumatism, and prevention of lipid peroxidation damage. Plant cell cultures are a means to study or to produce some active metabolites, such as polyphenols. This technique was applied to the investigation of coriander, and a detailed analysis of individual polyphenols in vivo and in vitro grown samples was performed. The in vivo vegetative parts showed quercetin derivatives as the main flavonoids and quercetin-3-O-rutinoside (3296 mg/kg dw) was the main polyphenol found in this part of coriander. The fruits revealed only phenolic acids and derivatives, caffeoyl N-tryptophan hexoside (45.33 mg/kg dw) being the most abundant phenolic derivative. In vitro samples also gave a high diversity of polyphenols, being C-glycosylated apigenin (2983 mg/kg dw) the main compound. Anthocyanins were only found in clone A, which was certainly related to its purple pigmentation, and peonidin-3-O-feruloylglucoside-5-O-glucoside was the major anthocyanin found (1.70 μg/kg dw). In vitro culture can be used to explore new industrial, pharmaceutical, and medicinal potentialities, such as the production of secondary metabolites like flavonoids.     

The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten

This study was designed to examine the in vitro antioxidant activities of the essential oil and methanol extracts of Satureja spicigera and S. cuneifolia from Turkish flora. GC and GC/MS analysis of the essential oils resulted in the identification of 40 and 29 compounds, representing the 99.4% and 99.5% of the oils, respectively. Major constituents of the oils were carvacrol (42.5% and 67.1%), γ-terpinene (21.5% and 15.2%) and p-cymene (20.9% and 6.7%), respectively. Methanol extracts were also obtained from the aerial parts of the plants. The samples were subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene–linoleic acid assays. In general, samples obtained from S. cuneifolia exerted greater antioxidant activities than did those obtained from S. spicigera. In the DPPH test system, free radical-scavenging activity of S. spicigera oil was determined to be 127 ± 1.63 μg/ml, whereas IC₅₀ value of S. cuneifolia was 89.1 ± 2.29 μg/ml. In the β-carotene–linoleic acid test system, antioxidant activities of the oil were 81.7 ± 1.14% and 93.7 ± 1.83%, respectively. Antioxidant activities of the synthetic antioxidant, BHT, ascorbic acid, curcumin and α-tocopherol were also determined in parallel experiments.     

Phytochemicals and antioxidant activity of different parts of bambangan (Mangifera pajang) and tarap (Artocarpus odoratissimus)

Mangifera pajang (family: Anacardiaceae; local name: bambangan) and Artocarpus odoratissimus (familiy: Moraceae; local name: tarap) are popular edible fruits in Sabah, Malaysia. The flesh, kernel and peel from M. pajang; seed and flesh from A. odoratissimus were analysed for total antioxidant activity, total polyphenol, total flavonoid and total anthocyanins contents. M. pajang kernel extract displayed the highest free radical scavenging and ferric reducing activities. Total phenolic content of the samples were in the range of 5.96–103.3 mg gallic acid equivalent/g. M. pajang kernel and M. pajang flesh contained the highest and lowest total flavonoid content with the values of 10.98 and 0.07 mg rutin equivalent/g, respectively. The antioxidant activities of extracts were significantly correlated with the total phenolic and flavonoid content (but not the anthocyanins content). The phytochemicals and antioxidant properties of M. pajang and A. odoratissimus, especially their by-products (kernel/seed), indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidant-rich nutraceuticals.     

Antioxidant activities of Salvia miltiorrhiza and Panax notoginseng

Traditional Chinese medicinal herb Salvia miltiorrhiza (SM) and Panax notoginseng (PN) have been widely used for the prevention and treatment of vascular diseases in the clinics. To better understand their mechanisms of pharmacological actions, the in vitro antioxidant activities of extract of Salvia miltiorrhiza (ESM) and extract of Panax notoginseng (EPN) were evaluated with different antioxidant testing systems. Their activities of scavenging superoxide anion radicals, DPPH radicals, hydroxyl radicals, and hydrogen peroxide, chelating Ferrous ion, and ferric ion reducing power were assessed. The results showed that the mechanisms of their antioxidant effects were distinct and diverse. ESM possessed strong reducing power and high scavenging activities against free radicals including superoxide anion, hydroxyl and DPPH radicals, but a weaker scavenging activity for hydrogen peroxide. ferrous ion chelating activity of ESM was undetectable at the tested concentrations. In contrary, EPN exhibited strong ferrous ion chelating activity and high scavenging activities against hydrogen peroxide, hydroxyl radicals, and a weak activity against superoxide anion and DPPH free radicals. EPN did not show any ferric ion reducing power. Since their antioxidant mechanisms are complementary, the combined use of ESM and EPN might be even more beneficial. These antioxidant properties of SM and PN are likely part of the reasons that they are effective in the prevention and treatment of vascular diseases.     

Chemical composition and biological activities of Algerian Thymus oils

The compositions of essential oils isolated from nine samples of three Thymus species (Thymus algeriensis, Thymus pallescens and Thymus dréatensis) were analysed by GC and GC–MS, and a total of 114 components were identified. T. pallescens collected from various regions showed a great similarity in their compositions and were characterised by carvacrol (44.4–57.7%), p-cymene (10.3–17.3%) and γ-terpinene (10.8–14.2%) as the major components for four samples; only one sample was thymol-rich (49.3%) with a small amount of carvacrol (9.0%). On the other hand, T. algeriensis showed a chemical polymorphism, even for samples from the same location, and two new chemotypes for this species were proposed. Oxygen-containing monoterpenes were the predominant class (76.3%) in T. dreatensis oil, with linalool (30.4%), thymol (20.2%) and geraniol (19.6%) as the principal constituents. The oils were screened for their possible antioxidant activities by four complementary assays, namely DPPH free radical scavenging, hydroxyl radical scavenging, inhibition of lipid peroxidation and reducing power. The two new chemotypes of T. algeriensis exhibited strong hydroxyl radical scavenging (IC₅₀ = 2.2–3.3 μg/ml), but were not or only slightly active against the other radicals and exhibited a weak reducing power. Despite their chemical similarity, T. pallescens oils sometimes produced significant differences in their antioxidant activities. The essential oils were also screened for their antimicrobial activity against five bacteria (three Gram-positive and two Gram-negative) and one yeast (Candida albicans). The tested essential oils showed antimicrobial activity against the microorganisms used, in particular against two important pathogens, C. albicans and Helicobacter pylori.     

Antioxidant properties of Agaricus blazei, Agrocybe cylindracea, and Boletus edulis

Three mushrooms are currently available in Taiwan, including Agaricus blazei, Agrocybe cylindracea, and Boletus edulis. Their ethanolic and hot water extracts were prepared and antioxidant properties studied. Ethanolic extracts from three mushrooms were more effective than hot water extracts in antioxidant activity using the conjugated diene method and scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals whereas hot water extracts were more effective in reducing power, scavenging ability on hydroxyl radials and chelating ability on ferrous ions as evidenced by their lower EC₅₀ values. Overall, for both extracts, B. edulis was more effective among antioxidant properties assayed. Naturally occurring antioxidant components including total tocopherols (3.18-6.18 mg/g) and total phenols (5.67-5.81 mg/g) were found in the extracts and their contents were associated (r=0.636-0.907) with EC₅₀ value of antioxidant properties. Based on the results obtained, both extracts from these three mushrooms were effective in antioxidant properties.     

Nutritional and nutraceutical comparison of Jamaican Psidium cattleianum (strawberry guava) and Psidium guajava (common guava) fruits

Psidium cattleianum (strawberry guava) is one of many underutilised edible fruits that grow wild in Jamaica, and could potentially be commercially exploited to yield health and economic benefits. In this study, the total phenolics, proximate contents, and antioxidant, anti-inflammatory, and antimicrobial activities of P. cattleianum and P. guajava (common guava), a well-known species, were compared. Strawberry guavas were found to be superior to common guavas in antioxidant and antimicrobial activities, total phenolics and vitamin C content. They also possessed relatively high fibre content (24.9%). The hexane and ethyl acetate extracts of strawberry guavas showed cyclooxygenase-2 enzyme inhibitory activities of 18.3% and 26.5%, respectively (250 μg/mL), indicating anti-inflammatory activity. The EtOAc and MeOH extracts of P. guajava showed 56.4% (COX-2) and 44.1% (COX-1) inhibitory activity, respectively. Additionally, nine compounds were isolated from strawberry guava fruits, some of which demonstrated anti-inflammatory activity. These results indicate that strawberry guavas are beneficial for health.     

Phenolics from hull of Garcinia mangostana fruit and their antioxidant activities

The air-dried fruit hulls of Garcinia mangostana Linn. were extracted with 70% MeOH, and then partitioned into the n-BuOH fractions. Furthermore, three major phenolic components related to their antioxidant activities were purified by silica gel column chromatography and Sephadex LH-20 and then identified as P₁ (1,3,6,7-tetrahydroxy-2,8-(3-methyl-2-butenyl)), P₂ [1,3,6-trihydroxy-7-methoxy-2,8-(3-methyl-2-butenyl) xanthone] and P₃ (epicatechin) using UV–visible spectrophotometry, IR spectrophotometry and NMR spectroscopy, respectively. The antioxidant activities of three major phenolics were evaluated using different tests, including the free radical scavenging capability and total antioxidant activity in a linoleic acid peroxidation. These three phenolic compounds exhibited different antioxidant activities in these antioxidant tests. The hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capabilities and the activity against linoleic acid peroxidation of P₁ were greater than those of P₂ and P₃, while the superoxide anion radical scavenging activity of P₃ was greater than that of P₁, but was close to that of P₂ or α-tocopherol. An activity-guided isolation and purification process was used to identify the components showing the strong DPPH radical scavenging activity from G. mangostana Linn.