Oat germination and ultrafiltration process improves the polyphenol and avenanthramide contents with protective effect in oxidative-damaged HepG2 cells.

Oat is the nutritious crop containing various compounds with antioxidant properties, such as polyphenols. In this study, we investigated the effect of germination and ultrafiltration process on polyphenol and avenanthramide contents in oat as well as their cytoprotective effect. Germination of oat for 48 hr significantly increased avenanthramide (5.5 to 11.3 mg/g) and polyphenol (115 to 155 mg GAE/g) contents. The compounds were more concentrated after ultrafiltration using 10 kDa membranes (polyphenol, 206 GAE/g; avenanthramide, 18 mg/g). In addition, oat extracts significantly reduced the cellular ROS level against tert-butyl hydroperoxide (t-BHP) stimulation in HepG2 cells. In the mechanistic study, oat extracts induced Nrf2 translocation to the nucleus by inhibition of Keap1 expression, resulting into upregulation of γ-GCS and NQO1. In conclusion, oat germination and ultrafiltration processes increased the polyphenol content, including that of avenanthramide. These extracts protected cells from t-BHP by radical scavenging activities and induced Nrf2 pathway activation. PRACTICAL APPLICATIONS: This study presents the method for avenanthramide-concentrated extract which is unique bioactive compounds in oat. In addition, antioxidant activity and their mechanisms of the avenanthramide-enriched extracts were evaluated. The polyphenol compounds including avenanthramide were found to increase after germination and ultrafiltration, thereby improving the radical scavenging ability. These results can be utilized as data for the development of health-promoting materials using oats.

Ecological Roles of Tryptanthrin, Indirubin and N-Formylanthranilic Acid in Isatis indigotica: Phytoalexins or Phytoanticipins?

Leaves of the plant species Isatis indigotica Fortune ex Lindl. (Chinese woad) produce the metabolites tryptanthrin, indirubin and N-formylanthranilic acid upon spraying with an aqueous solution of copper chloride but not after spraying with water. The antifungal activities of these metabolites against the phytopathogens Alternaria brassicicola, Leptosphaeria maculans and Sclerotinia sclerotiorum established that tryptanthrin is a much stronger growth inhibitor of L. maculans than the phytoalexin camalexin. The biosynthetic precursors of tryptanthrin and N-formylanthranilic acid are proposed based on the deuterium incorporations of isotopically labeled compounds. The overall results suggest that tryptanthrin is a phytoalexin and indirubin and N-formylanthranilic acid are phytoanticipins in the plant species I. indigotica and that chemical diversity and biodiversity are intimately connected.

Seven new anthranilamide derivatives from Aconitum apetalum.

Seven new anthranilamide derivatives, acoapetalines A-G (1-7), including one new naturally occurring compound (7), together with six known ones (8-13) were isolated from the whole plants of Aconitum apetalum. Their structures were established on the basis of extensive spectroscopic analyses (IR, UV, HRESIMS, 1D and 2D NMR). All compounds were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compound 10 exhibited significant anti-TMV activity with an inhibition rate of 67.57% (100 µg/mL), which was higher than that of ningnamycin (52.89%).

N-acylanthranilic acid derivatives with anti-Aß1-42 aggregation activity from the leaves of Isatis indigotica fortune.

Seven new N-acylanthranilic acid derivatives (1-3, 4a/4b, 5a/5b) including two pairs of enantiomers (4a/4b and 5a/5b) were isolated from the leaves of Isatis indigotica Fortune. Their chemical structures were elucidated by extensive spectroscopic data analyses. The absolute configurations of compounds 4a/4b and 5a/5b were determined by comparison of the experimental and calculated ECD spectra. All compounds were tested for their anti-Aß1-42 aggregation activity. As a result, compounds 1 (72.1%), 2 (79.8%) and 5a (81.8%) showed stronger inhibitory activity than the positive control curcumin (67.0%). By the comparison between 5a (81.8%) and 5b (63.1%), it was found that stereochemical configurations may affect Aß1-42 aggregation activity, which was discussed through the molecular docking results of compounds 5a and 5b.

Induction of new metabolites from the endophytic fungus Bionectria sp. through bacterial co-culture.

A new alkaloid, 1,2-dihydrophenopyrrozin (1), along with five known compounds (2-6) was isolated from an axenic culture of the endophytic fungus, Bionectria sp., obtained from seeds of the tropical plant Raphia taedigera. Co-cultivation of this fungus either with Bacillus subtilis or with Streptomyces lividans resulted in the production of two new o-aminobenzoic acid derivatives, bionectriamines A and B (7 and 8) as well as of two additional known compounds (9 and 10). None of the latter compounds (7-10) were detected in axenic cultures of the fungus or of the bacteria indicating activation of silent biogenetic gene clusters through co-cultivation with bacteria. The structures of the new compounds were unambiguously determined based on detailed NMR and MS spectroscopic analysis and by comparison with the literature. The crystal structure of agathic acid (6) is reported here for the first time. Penicolinate A (4) exhibited potent cytotoxic activity against the human ovarian cancer cell line A2780 with an IC50 value of 4.1µM.

Dianthosaponins G-I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity.

Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G-I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated.

New series of avenanthramides in oat seed.

Avenanthramides are characteristic constituents of oat seeds. We analyzed the methanol extract of oat seeds by HPLC and detected three compounds 1, 2, and 3 eluted at retention times similar to avenanthramides. The three compounds were purified by column chromatography and HPLC. Spectroscopic analyses of 1, 2, and 3 suggested that they are amides of 4,5-dihydroxyanthranilic acid with caffeic, p-coumaric, and ferulic acids, respectively. Their identities were confirmed by comparing spectra and chromatographic behavior with compounds synthesized from 4,5-dihydroxyanthranilic acid and N-hyrdroxysuccinimide esters of hydroxycinnamic acids. LC-MS/MS analysis with multiple reaction monitoring showed that the amounts of 1, 2, and 3 were 16.5-26.9% of corresponding avenanthamides with 5-hydroxyanthranilic acid. Compounds 1, 2, and 3 showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the corresponding avenanthramides with 5-hydroxyanthranilic acid, indicating the involvement of 4,5-dihydroxyanthranilic acid moiety in the scavenging of DPPH radicals.

In vivo anti-inflammatory activity of some naturally occurring O- and N-prenyl secondary metabolites.

A series of O- and N-prenyl secondary metabolites of insect, fungal, and plant origin have been evaluated for their topical anti-inflammatory activity using the Croton oil ear test in mice as a model of acute inflammation. Some of the tested compounds revealed an effect (ID50 = 0.31 divided by 0.56 micromol/cm2) comparable with that of the reference non-steroidal anti-inflammatory drug indomethacin (ID50 = 0.23 micromol/cm2).

The green oat story: possible mechanisms of green color formation in oat products during cooking.

Consumers occasionally report greenish colors generated in their oat products when cooking in tap water. Here we have investigated pH and ferrous (Fe(2+)) ion as possible mechanisms for this color change. Steel-cut oat groats can turn brown-green color when cooked in alkaline conditions (pHs 9 to 12). Extraction of this color with methanol, and high-pressure liquid chromatography indicated a direct association of this color with the phenolic acid or avenanthramide content of the oat. The presence of 50 mM NaHCO(3) in water will cause oat/water mixtures to turn alkaline when cooked as CO(2) is driven off, generating OH(-) ion. Although tap water rarely, if ever, contains so much bicarbonate, bicarbonate is used as a leavening agent in baking applications. Industrial interests using baking soda or alkaline conditions during oat processing should be aware of possible off color generation. We have also found that as little as 10 ppm Fe(2+) will turn oat products gray-green when cooked. The aleurone stained darker than the starchy endosperm. Other divalent cations, such as Ca(2+) or Mg(2+) had no effect on cooked oat color. As much as 50 ppm Fe(2+) may be found in freshly pumped well water, but Fe(2+) reacts quickly with oxygen and precipitates as Fe(OH)(3). Thus, some freshly pumped well water may turn oats green when cooked, but if the water is left under atmospheric conditions for several hours, no discoloration will appear in the cooked oats.

Triterpenoid saponin anthranilates from Albizia grandibracteata leaves ingested by primates in Uganda.

Three new oleanane-type triterpene saponins (1-3), named grandibracteosides A-C, were isolated from the methanolic extract of leaves of Albizia grandibracteata, a species consumed by primates in the Kibale National Park, Uganda. The structures of the saponins were established using 1D and 2D NMR experiments and mass spectrometry and confirmed by acid and alkaline hydrolysis. The crude extract and the pure compounds showed significant inhibitory activity against KB and MCF7 tumoral cell lines in vitro. The compounds are glycosides of acacic acid acylated by an o-aminobenzoyl unit. This is the first report of such ester saponins in dicotyledonous plants. Studies of the primate diet may provide a useful method for finding naturally occurring compounds of medicinal significance.

The anti-endotoxic effect of o-aminobenzoic acid from Radix Isatidis.

AIM: To study the anti-endotoxic effect of o-aminobenzoic acid (OABA) isolated from Banlangen(BLG). METHODS: OABA was extracted and isolated from BLG and diluted into 0.5% solution. The concentration of endotoxin (ET) pretreated with OABA was quantitatively detected using Limulus test. The inhibition of ET-induced fever by OABA was measured in rabbits. The rates of lipopolysaccharides (LPS)-induced death in mice pretreated with or without OABA were then compared. The influence of OABA on the release of TNF-alpha and NO from macrophages induced by LPS was examined in mice. RESULTS: After pretreatment with OABA, 84.4% of ET was destroyed. The ET-induced fever in rabbits decreased significantly and the rate of LPS-induced death in mice dropped from 70% to 20%. The release of TNF-alpha and NO induced by LPS in mice was inhibited dose-dependently when the concentration of OABA was between 0.125% and 0.5%. CONCLUSION: OABA isolated from BLG has an anti-endotoxic effect.

Triterpenoid constituents of Raulinoa echinata.

A phytochemical investigation of the stems of the South Brazilian endemic species Raulinoa echinata has led to the isolation of two new methoxylated protolimonoid epimers (1 and 2) together with the known melianone and melianodiol. The leaves afforded three glabretal-type triterpene derivatives esterified by N-methylanthranilic acid (3-5). Compounds 1 and 2 displayed weak inhibitory activity when assayed in vitro against trypomastigote forms of Trypanosoma cruzi. Compounds 1-5 were inactive in a brine shrimp (Artemia salina) lethality test.

Secoiridoid glycosides and an antifungal anthranilate derivative from Gentiana tibetica.

Repetitive chromatography of the methanol extract of the roots of Gentiana tibetica afforded two new secoiridoid glycosides and a novel antifungal anthranilic acid derivative, together with beta-sitosterol, daucosterol, oleanolic acid, loganic acid, gentiopicroside, sweroside, 2'-(2,3-dihydroxybenzoyl)sweroside, trifloroside, rindoside and macrophylloside A. The structures of the new products were determined mainly by spectroscopic methods as 8-hydroxy-10-hydrosweroside, isomacrophylloside and ethyl N-docosanoylanthranilate. Ethyl N-docosanoylanthranilate inhibited the growth of the human pathogenic fungi Candida albicans and Aspergillus flavus. The taxonomic significance of the constituent is discussed briefly.

New antitumor antibiotics, FR-900405 and FR-900406. II. Production, isolation, characterization and antitumor activity.

The new antitumor antibiotics, FR-900405 and FR-900406, were isolated from the culture broth of Actinomadura pulveracea sp. nov. No. 6049. These compounds which contain sulfur in the molecule, represent a novel class of antitumor agents. FR-900405 and FR-900406 are highly active in mice against experimental tumors and exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi.