Secoiridoid and iridoid glucosides from Syringa afghanica

Phytochemical investigation of the dried leaves of Syringa afghanica, has led to the isolation of nine secoiridoid glucosides, safghanosides A-H and 2"-epi-frameroside, as well as an iridoid glucoside, syringafghanoside along with nineteen known compounds. The structures were elucidated by spectroscopic and chemical means.     

Secoiridoid analogues from the fruits of Ligustrum lucidum and their inhibitory activities against influenza A virus

A phytochemical study focusing on the secoiridoid components in the fruits of Ligustrum lucidum was carried out, which finally led to the isolation of nine secoiridoid glycosides (1–9) together with two secoiridoids (10, 11). The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence, of which 1, 2, 4 (ligulucisides A–C), 10 and 11 (liguluciridoids A and B) were identified as new secoiridoid analogues. An in vitro antiviral bioassay indicated that 1, 4, 6, and 10 displayed the inhibitory activities against influenza A virus with the IC₅₀ values of 16.5, 12.5, 13.1, and 18.5?μM, respectively, which were better than the positive control Ribavirin (IC₅₀ 22.6?μM)..     

Stilbenes from the roots of Pleuropterus ciliinervis and their antioxidant activities

Two stilbene glycosides, pieceid-2"-O-gallate and pieceid-2"-O-coumarate, were isolated from the MeOH extract of the roots of Pleuropterus ciliinervis Nakai (Polygonaceae), together with two known compounds, resveratrol and pieceid. Their structures were determined spectroscopically, particularly by 2D NMR spectroscopic analysis. The antioxidant activities of stilbenes isolated were determined in vitro against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals and by determining their lipid peroxidation inhibitory activities. Among the compounds isolated, pieceid-2"-O-gallate had the most potent inhibitory scavenging effect on DPPH, superoxide radicals and upon lipid peroxidation inhibition with IC50 values of 16.5, 23.9 and 5.1 microM, respectively.     

Carboxymethylation of polysaccharides from Auricularia auricula and their antioxidant activities in vitro

The chemical carboxymethylated polysaccharide (CMAAP), which is derived from the poorly water-soluble, crude polysaccharide from Auricularia auricula (AAP), was prepared. The degree of substitution of CMAAP was 0.857, and its solubility in water reached 0.6 mg/mL, much higher than that of AAP (0.1 mg/mL). One fraction, CMAAP22, was purified. Chemical analysis indicated that CMAAP22 was composed of mannose and glucose in a ratio of 1.06:1 with a molecular weight of 3.4 × 10⁶ Da. IR spectra and ¹³C NMR spectra indicated that the C2, C4 and C6 positions were partially substituted by -CH₂COOH. AFM revealed that CMAAP22 was spherical particle structure with a diameter of 80-300 nm. Moreover, the antioxidant activity of CMAAP22 was improved, nearly twice as much as that of the AAP, especially in the scavenging of DPPH and ABTS+.     

Steryl esters and phenylethanol esters from Syringa komarowii

Three new steryl esters and a new phenylethanol ester, together with 22 known compounds were isolated from the aqueous ethanolic extract of the whole plants of Syringa komarowii. The new compounds were elucidated as stigmastane-3beta,6alpha-diol 3-O-tetradecanoate (1), stigmastane-3beta,6alpha-diol 3-O-palmitate (2), stigmastane-3beta,6alpha-diol 3-O-stearate (3), and 2-(4-hydroxyphenyl)-ethyl dotriacontanoate (4) on the basis of extensive spectral data and chemical evidences.     

Chromones from the tubers of Eranthis cilicica and their antioxidant activity

Chemical studies on the constituents of Eranthis cilicica led to isolation of ten chromone derivatives, two of which were previously known. Comprehensive spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of enzymatic hydrolysis allowed the chemical structures of the compounds to be assigned as 8,11-dihydro-5-hydroxy-2,9-dihydroxymethyl-4H-pyrano[2,3-g][1]benzoxepin-4-one, 5,7-dihydroxy-8-[(2E)-4-hydroxy-3-methylbut-2-enyl]-2-methyl-4H-1-benzopyran-4-one, 5,7-dihydroxy-2-hydroxymethyl-8-[(2E)-4-hydroxy-3-methylbut-2-enyl]-4H-1-benzopyran-4-one, 7-[(β-d-glucopyranosyl)oxy]-5-hydroxy-8-[(2E)-4-hydroxy-3-methylbut-2-enyl]-2-methyl-4H-1-benzopyran-4-one, 7-[(β-d-glucopyranosyl)oxy]-5-hydroxy-2-hydroxymethyl-8-[(2E)-4-hydroxy-3-methylbut-2-enyl]-4H-1-benzopyran-4-one, 9-[(O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl)oxy]methyl-8,11-dihydro-5,9-dihydroxy-2-methyl-4H-pyrano[2,3-g][1]benzoxepin-4-one, 8,11-dihydro-5,9-dihydroxy-9-hydroxymethyl-2-methyl-4H-pyrano[2,3-g][1]benzoxepin-4-one, and 7-[(O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl)oxy]methyl-4-hydroxy-5H-furo[3,2-g][1]benzopyran-5-one, respectively. The isolated compounds were evaluated for their antioxidant activity.     

Antioxidant activities of polysaccharides from Lentinus edodes and their significance for disease prevention

The crude polysaccharide (LEP) was extracted by hot water from the fruiting bodies of Lentinus edodes, and further purified by DEAE-cellulose and Sepharose CL-6B chromatography, giving three polysaccharide fractions coded as LEPA1, LEPB1 and LEPC1. In this study, their chemical and physical characteristics of polysaccharide fractions and antioxidant capacities, including scavenging activity against hydroxyl radicals, superoxide radicals and Fe²⁺-chelating ability, were valuated. The results showed that LEPC1 exhibited significantly antioxidant activity at a concentration-dependent manner. Therefore these results indicated that the water-extractable polysaccharide fraction was a potent antioxidant and could be developed to be new health medicine for fighting against various human diseases.     

Synthesized oversulfated and acetylated derivatives of polysaccharide extracted from Enteromorpha linza and their potential antioxidant activity

Sulfated polysaccharide extracted from blue algae Enteromorpha linza is proved to possess excellent antioxidant activities. Two derivatives by means of oversulfated and acetylated coupling were synthesized and investigated their antioxidant activities including scavenging effect of superoxide, hydroxyl and 1,1-diphenyl-2-picrylhydrazyl radicals. And then the relationship between antioxidant activity and chemical characteristics was characterized. The results of chemical analysis and FT-IR showed that the modification of polysaccharide was successful. In addition, it was found that certain derivatives exhibited stronger antioxidant activity than raw material. They could serve as free-radical inhibitors or scavengers, acting possibly as primary antioxidants.     

Phenylpropanoid glucosides from leaves of Coussarea hydrangeifolia (Rubiaceae)

Phenylpropanoid glycosides, 1'-O-benzyl-alpha-L-rhamnopyranosyl-(1'-->6')-beta-D-glucopyranoside (1) and alpha-L-xylopyranosyl-(4'-->2')-(3-O-beta-D-glucopyranosyl)-1'-O-E-caffeoyl-beta-D-glucopyranoside (2), together with the known derivatives, 1,6-di-O-caffeoyl-beta-D-glucopyranoside (3), 1-O-(E)-caffeoyl-beta-D-glucopyranoside (4) and 1-O-(E)-feruloyl-beta-D-glucopyranoside (5), were isolated from leaves of Coussarea hydrangeifolia. Their structures were determined by IR, HRESIMS, and 1D and 2D NMR experiments, and their antioxidant activities, evaluated by assaying the free radical scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical as substrate. The antioxidant activities of 3 and 4 (IC50 values of 15.0 and 19.2 microM, respectively) were comparable to that of the standard positive control caffeic acid, whilst 2 and 5 were only weakly active and 1 was inactive.     

Acylated quercetagetin glycosides with antioxidant activity from Tagetes maxima

The fractionation of a methanolic extract of Tagetes maxima guided for antioxidant activity resulted in the isolation of three acylated quercetagetin glycosides, quercetagetin-7-O-(6-O-caffeoyl-beta-D-glucopyranoside), quercetagetin-7-O-(6-O-p-coumaroyl-beta-D-glucopyranoside) and quercetagetin-7-O-(6-O-galloyl-beta-D-glucopyranoside), as well as four known flavonoid glycosides. The structural elucidation was accomplished by spectroscopic methods (ESI-MS/MS and NMR). The antioxidant activity of fractions and isolated compounds was determined by checking the scavenging activity against three different radicals: 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH*), hydroxyl (*OH), and superoxide (O2*-). The three isolated compounds exhibited a high radical scavenging activity in comparison with reference compounds.     

Chromone and chromanone glucosides from Hypericumsikokumontanum and their anti-Helicobacter pylori activities

Chromone glucosides, takanechromones A-C (1, 2 and 5) and chromanone glucosides, named takanechromanones A and B (3 and 4), were isolated from the methanolic extracts of Hypericumsikokumontanum together with 27 known compounds. Their structures were established based on spectroscopic evidence. The isolated compounds and some chromone derivatives were assayed for antimicrobial activity against Helicobacter pylori and cytotoxicity against human cancer cell lines.     

Structural analysis of water-soluble polysaccharides in the fruiting body of Dictyophora indusiata and their in vivo antioxidant activities

The water-soluble Dictyophora indusiata polysaccharides (DIP) were extracted from the fruiting body of D. indusiata. The structural features of purified DIPs I and II were investigated. The results indicated that DIP I was composed of glucose (Glc) and mannose (Man) with molecular weight of 2100 kDa, while DIP II comprised of xylose (Xyl), galactose (Gal), glucose (Glc) and Man with molecular weight of 18.16 kDa. The glycosidic linkage of DIP I was composed of →1)-Glc-(6→: →1)-Man-(3,6→ with the ratio of 5.6:1.0, while DIP II was composed of →1)-Glc-(6→: →1)-Man-(3,6→: →1)-Xyl-(5→: →1)-Gal-(3→: →1)-Gal-(6→: with the ratio of 4.9: 15.5: 7.8: 1.0: 5.7. DIP significantly (P < 0.05) decreased the malondialdehyde (MDA), lipofuscin levels and increased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities of mice. The strong in vivo antioxidant activity indicated DIP had great potential as functional food.     

Aromatase inhibitory, radical scavenging, and antioxidant activities of depsidones and diaryl ethers from the endophytic fungus Corynespora cassiicola L36

Isolation of a broth extract of the endophytic fungus Corynespora cassiicola L36 afforded three compounds, corynesidones A (1) and B (3), and corynether A (5), together with a known diaryl ether 7. Compounds 1, 3, 5, and 7 were relatively non-toxic against cancer cells, and inactive toward normal cell line, MRC-5. Corynesidone B (3) exhibited potent radical scavenging activity in the DPPH assay, whose activity was comparable to ascorbic acid. Based on the ORAC assay, compounds 1, 3, 5, and 7 showed potent antioxidant activity. However, the isolated natural substances and their methylated derivatives (1−8) neither inhibited superoxide anion radical formation in the XXO assay nor suppressed TPA-induced superoxide anion generation in HL-60 cell line. Corynesidone A (1) inhibited aromatase activity with an IC₅₀ value of 5.30 μM.     

Isolation and antioxidant activities of polysaccharides extracted from the shoots of Phyllostachys edulis (Carr.)

Polysaccharides extracted from Phyllostachys edulis (Carr.) are a group of hetero polysaccharides, and their antioxidant activities were investigated employing various established in vitro systems. Available data obtained with in vitro models suggested that among the three samples, B1 (extraction with water) showed significant inhibitory effects on superoxide radical and hydroxyl radical; its reducing power was also the strongest among the three samples. These results clearly establish the possibility that polysaccharides extracted from P. edulis could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted in experimental animal models.     

Proanthocyanidin glycosides and related polyphenols from cacao liquor and their antioxidant effects

Purification of polar fractions from cacao liquor extracts gave 17 phenolics including four new compounds. The new compounds were characterized as a C-glycosidic flavan, an O-glycoside of a dimeric and two O-glycosides of trimeric A-linked proanthocyanidins, on the basis of spectroscopic data. Isolated polyphenols showed inhibitory effects on nicotinamide adenine dinucleotide phosphate-dependent lipid peroxidation in microsomes and on the autoxidation of linoleic acid. These effects were attributed to the radical-scavenging activity in the peroxidation chain reactions, based on the findings that the cacao polyphenols effectively scavenged the 1,1-diphenyl-2-picrylhydrazyl radical.     

South African Lippia herbal infusions: Total phenolic content,antioxidant and antibacterial activities

Lippia javanica and Lippia scaberrima are used as herbal remedies and are commercially traded as health teas in southern Africa under the brands “Mosukujane” and “Musukudu”, respectively. This study evaluates the relationship between the presence of phenolic compounds and the antioxidant activities of infusions prepared from four Lippia species (L. javanica, L. scaberrima, L. rehmannii and L. wilmsii) indigenous to South Africa. The antioxidant activities of the infusions, determined by the 2,2-diphenylpycrylhydrazyl (DPPH) method, were also compared to those of popular black, green and herbal tea brands. Of the four indigenous species, infusions of L. javanica and L. wilmsii exhibited the highest antioxidant activities (EC₅₀: 358 and 525 µg/ml, respectively) and contained the most phenolic compounds (14.8 and 14.5 mg/ml of dry weight gallic acid equivalent, respectively). Antibacterial activities of methanolic extracts of the four Lippia species were determined against four human pathogens (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa). The extract of L. javanica was the most active against all the pathogens tested. Those Lippia species (L. javanica and L. wilmsii) previously reported to produce higher levels of the pharmacologically active phenylethanoid glycosides verbascoside and isoverbascoside, portrayed stronger antioxidant and antibacterial activities. This study gives credence to the use of infusions of these Lippia species for their general health benefits.     

Bioactivities of water-soluble polysaccharides from fruit shell of Camellia oleifera Abel: Antitumor and antioxidant activities

Polysaccharides were extracted from fruit shell of Camellia oleifera Abel. Fruit shell of Camellia oleifera Abel polysaccharide (WEP2) was a water-soluble compound. Its molecular weight was about 362 kDa. HPLC analysis showed that this polysaccharide was composed of rhamnose, fucose, arabinose, mannose, galactose and glucose in the molecular ratio of 4.05, 11.62, 1.78, 3.91, 8.76 and 27.06, respectively. The broad intense characteristic peak around 3463 cm⁻¹ due to the hydroxyl stretching vibration of the polysaccharide was observed in the polysaccharide. The characteristic absorption bands at 852 cm⁻¹ and 893 cm⁻¹ indicated that WEP2 contained both α-glycosidic and β-glycosidic linkages. WEP2 exhibited remarkable antitumor activity against Sarcoma180 cell compared to the negative control group. At the highest dose 40 mg/kg days, the tumor inhibition rate reached 65.2%. The scavenging effects of WEP2 to hydroxyl radical and superoxide radical anion were 72.5% and 86.3% at a concentration of 1.0 mg/ml, respectively.     

In vitro antioxidant activities of sulfated polysaccharide fractions extracted from Corallina officinalis

Sulfated polysaccharides (F1, F2) from seaweed Corallina officinalis were isolated through anion-exchange column chromatography. Their chemical characteristics were determined by GC, HPLC, FT-IR and UV spectra. F1 and F2 contained only two monosaccharides, namely galactose and xylose. The antioxidant activities of F1, F2 and the de-sulfated polysaccharides (DF-1, DF-2) in vitro were investigated, including hydroxyl radicals scavenging effect, superoxide radical scavenging capacity, DPPH radical activity and reducing power. As expected, antioxidant assay showed that the two sulfated polysaccharide fractions (F1, F2) possessed considerable antioxidant properties and had more excellent abilities than de-sulfated polysaccharides (DF-1, DF-2).     

Norditerpene alkaloids from Delphinium linearilobum and antioxidant activity

From the roots of Delphinium linearilobum (Trautv.) N. Busch two new norditerpene alkaloids linearilobin and linearilin, and the known alkaloids lycoctonine, 14-acetyltalatizamine, browniine, cammaconine, talatizamine, and cochlearenine were isolated. Spectroscopic techniques were used for structure determination. Antioxidant activity was performed by DPPH and metal chelating activity assays.