Removal of C9-aldehydes and -alcohols from melon juice via cysteine addition.

BACKGROUND: The aroma of a melon fruit is among the most crucial qualities that influence consumer preferences. However, strong grassy and cucumber-like aromas can prevent consumer acceptance. These grassy and cucumber-like aromas are produced by aldehydes containing nine-carbon chains. Several studies have revealed that aldehydes exhibit a high affinity toward cysteine. Thus, the effect of adding cysteine to volatile compounds to melon juice was investigated. RESULTS: The volatile compounds released from the melon juice were analyzed via solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) after 0.5, 5, and 24 h of adding cysteine. The results indicated that the concentrations of aldehydes, such as (E,Z)-2,6-nonadienal and (E)-2-nonenal, in the melon juice decreased after the addition of cysteine at all the analyzed times. Additionally, (E)-2-nonenol and (E,Z)-2,6-nonadien-1-ol, which were formed by the enzymatic reduction of the aldehydes, also decreased by cysteine addition. To confirm the binding of cysteine with the aldehydes, two cysteine adducts were analyzed via liquid chromatography-mass spectrometry (LC-MS) employing (E)-2-nonenal in the melon juice after the addition of cysteine. CONCLUSION: This study demonstrates that cysteine addition could be potentially used to reduce the grassy and cucumber-like aromas of melon juice. © 2022 Society of Chemical Industry.

Omphaloprenol A: a new bioactive polyisoprenepolyol isolated from the mycelium of poisonous mushroom Omphalotus japonicus.

Mushrooms of the Omphalotus genus are known to be rich in secondary metabolites. In the quest for new bioactive compounds, we analyzed the compounds isolated from the mycelium of the poisonous mushroom Omphalotus japonicus. As a result, a new polyisoprenepolyol, which was named omphaloprenol A, was identified, along with known substances such as hypsiziprenol A10 and A11, illudin S, and ergosterol. The chemical structure of omphaloprenol A was elucidated by nuclear magnetic resonance and infrared spectroscopies and mass spectrometry, and its bioactivity was investigated. Omphaloprenol A showed growth promoting activity against the root of lettuce seeds and cytotoxicity against HL60 cells. To the best of our knowledge, this is the first report on the isolation of a polyisoprenepolyol compound from Omphalotaceae mushrooms.

Isopentylamine is a novel defence compound induced by insect feeding in rice.

Plants produce a broad variety of defensive metabolites to protect themselves against herbivorous insects. Although polyamines have been implicated in various responses to abiotic and biotic stress, there have been no studies focused on amines in response to insect herbivory. By screening for bioactive amines, we identified isopentylamine as a novel type of herbivory-induced compound in rice leaves, which was derived from the amino acid leucine in stable isotope labelling experiments. Accumulation of isopentylamine increased during herbivory by the brown planthopper (Nilaparvata lugens, BPH) and the rice-feeding armyworm (Mythimna loreyi), as well as in response to treatment with the plant hormone, jasmonic acid. Likewise, isopentylamine accumulation was compromised in rice jasmonate biosynthesis mutants, hebiba and Osjar1. In bio-assays, BPH insects feeding on rice seedlings submerged in 50 mg/L isopentylamine solution had a higher mortality compared with BPH feeding on seedlings submerged in water. Notably, the rice leaves submerged in 50 mg/L solution showed the endogenous concentrations of isopentylamine similar to that induced by BPHs. These results suggest that isopentylamine functions as a new type of plant defence metabolite that is rapidly induced by herbivore attack and deters insect herbivores in rice.

Changes of volatile flavor compounds of watermelon juice by heat treatment.

Changes of volatile flavor compounds of watermelon juice by heat treatment were investigated by gas chromatography-olfactometry-mass spectrometry. Although the major volatile compounds in watermelon juice, three aldehydes, three alcohols, and one ketone, did not increase significantly by heat treatment, dimethylsulfide and methional increased in heated juice. These two sulfides were suggested to contribute to the off-flavors in heated watermelon juice.

Constituents of the Fruiting Body of Poisonous Mushroom Omphalotus japonicus.

Six new sesquiterpenes, tsukiyols A-C, neoilludin C, and 4-O-methylneoilludins A and B, were isolated from the fruiting body of Omphalotus japonicus (Kawam.) Kirchm. & O. K. Mill. Additionally, six known compounds, illudin S, neoilludins A-B, 5-hydroxydichomitol, ergosterolperoxide, and 3ß,5α,9α-trihydroxyergosta-7,22-diene-6-one, were also obtained. Their chemical structures were determined with MS, IR, and NMR spectra and the absolute configurations of neoilludins A-C, 4-O-methylneoilludins A, and B were determined with electronic circular dichroism (ECD). Illudin S and 3ß,5α,9α-trihydroxyergosta-7,22-diene-6-one showed cytotoxicity against human acute promyelocytic leukemia HL60 cells. Illudin S, 4-O-methylneoilludin A, B, and tsukiyol C showed growth-restoring activity against mutant yeast via Ca2+-signal transduction.

A herbivore-induced homoterpene volatile is emitted from Basella alba leaves.

An irregular C11 homoterpene, (E)-4,8-dimethylnona-1,3,7-triene (DMNT) was identified as a major component of the volatile compounds emitted from Basella alba leaves induced by herbivore. The terpenes including DMNT were not detected from the leaves infected by Botrytis cinerea. These results suggested that volatile emission from B. alba leaves was induced by herbivory but not by a fungal infection.

New isocoumarins, naphthoquinones, and a cleistanthane-type diterpene from Nectria pseudotrichia 120-1NP.

Four new compounds, namely, nectriapyrones A (2) and B (3), nectriaquinone B (5), and zythiostromic acid C (8), were isolated from the brown rice culture of Nectria pseudotrichia 120-1NP together with four known compounds (1, 4, 6, and 7). To the best of our knowledge, this is the first report of 4 from a natural source. Their structures were determined on the basis of 1D/2D-NMR spectroscopy and HRESITOFMS data. In addition, the absolute configuration of secondary alcohols in 8 were determined using modified Mosher's ester method. All isolated compounds were evaluated for their antimicrobials activity, phytotoxicity, and cytotoxicity.

Spectroscopic characterisation of two polyketide metabolites from Cylindrocarpon sp. from driftwood.

Two new polyketides, (5R,7R,9R)-7,9-dihydroxy-5-decanolide and (4E,6R,9R)- 6,9-dihydroxydec-4-enoic acid (2), were isolated from rice cultures of Cylindrocarpon sp. SY-39 discovered during screening of driftwood at a Shonai coast area in Yamagata, Japan. The structures of 1 and 2 were determined using a variety of spectroscopic methods. Compound 2 exhibited moderate antimicrobial activity against Staphylococcus aureus NBRC 13276 and Aspergillus clavatus F 318a at a concentration of 50 µg per disk.

Flavonoid glycosides in Malabar spinach Basella alba inhibit the growth of Spodoptera litura larvae.

Basella alba is a perennial plant of the Basellaceae and is known by various common names including Malabar spinach. There are few insects that cause damage to B. alba. In this study, we examined the effect of B. alba leaves on the growth of Spodoptera litura larvae. B. alba leaves and a methanolic extract of the leaves inhibited the growth of S. litura larvae. Half of the larvae reared on the leaves died within 1 week. We found that two flavonoids, vitexin, and vitexin-2″-O-arabinofuranoside, were abundant in the methanol extract of leaves. When larvae were reared on purified vitexin or vitexin-2″-O-arabinofuranoside, their growth was significantly impaired compared with larvae reared on control spinach leaves. These results suggested that the flavonoid glycosides in B. alba leaves act as deterrents to S. litura larvae.

New Metabolites Produced by Cylindrocarpon sp. SY-39 from a Driftwood.

Four novel compounds, cylindropyrone A (1), 10'-hydroxyilicicolinic acid D (3), cylindrolactones A (4) and B (5), together with known dihydroinfectopyrone (2) were isolated from the culture of Cylindrocarpon sp. SY-39 from a driftwood. Their structures were elucidated using 1D- and 2D-NMR spectroscopy. Compound 3 showed antimicrobial activity against Staphylococcus aureus with MIC value of 5.0 µg/mL.

New eremophilane and dichlororesorcinol derivatives produced by endophytes isolated from Ficus ampelas.

The novel compound, 11-O-methylpetasitol (1), was isolated from Penicillium sp. N-175-1, and two new compounds, cosmochlorins D (5) and E (6), were isolated from Phomopsis sp. N-125. In addition, three known eremophilane sesquiterpenes, sporogen-AO1 (2), petasol (3) and 6-dehydropetasol (4), were isolated from Penicillium sp. N-175-1. The structures of 1, 5 and 6 were elucidated by a combination of extensive spectroscopic analyses, including 2D NMR, high-resolution electrospray ionization time-of-flight mass spectrometry (HRESITOFMS) and chemical reactions. Compounds 2, 3, 5 and 6 exhibited cytotoxicity to HL60 and 2 and 3 to HeLa cells. Furthermore, 2 and 3 showed robust growth-restoring activity of a Saccharomyces cerevisiae (cdc2-1 rad9Δ) mutant strain, whereas 5 and 6 exhibited minor growth-restoring activity in this strain. Thus, these compounds may inhibit the growth of HL60 and HeLa cells by blocking the cell cycle, and they may be utilized as new lead compounds that act as inhibitors of survival signal transduction pathways.

A phytotoxic bicyclic lactone and other compounds from endophyte Xylaria curta.

A new compound, (3aS,6aR)-4,5-dimethyl-3,3a,6,6a-tetrahydro-2H-cyclopenta [b]furan-2-one (2), along with two known metabolites, myrotheciumone A (1) and 4-oxo-4H-pyron-3-acetic acid (3) was isolated from the ethyl acetate extract of fermentation broth of Xylaria curta 92092022. The structures of these compounds were elucidated on the basis of spectroscopic methods (UV, IR, HRESITOFMS, 1D NMR, and 2D NMR). Compounds 1 and 2 showed moderate antibacterial and phytotoxic activities.

Ethyl acetate fraction of Garcina epunctata induces apoptosis in human promyelocytic cells (HL-60) through the ROS generation and G0/G1 cell cycle arrest: a bioassay-guided approach.

Number of deaths due to cancer diseases is increasing in the world. There is an urgent need to develop alternative therapeutic measures against the disease. Our study reports the cytotoxicity activity of Garcina epunctata (gutifferae) in human promyelocytic leukemia cells (HL-60) and prostate cancer cells (PC-3) was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Changes in mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and morphological changes associated with apoptosis were examined by flow cytometry and Hoescht staining respectively. The results of in vitro antiproliferative screening of fractions and extract from G. epunctata indicated that three fractions inhibited the viability of PC-3 cells with IC50 varied from 50 to 88 µ/ml while two fractions inhibited the proliferation of HL-60 cells with IC50 range between 47.5 and 12 µg/ml. Among the entire fraction tested, Hex-EtOAc (75:25) showed cytotoxic effects on the two cell lines and EtOAc fraction was most active only HL-60 cells (12 µg/ml). Treatment of HL-60 cells with G. epunctata (20, 50, 100 µg/ml) for 24 h led to a significant dose-dependent increase in the percentage of cells in sub-G1 phase by analysis of the content of DNA in cells, and a number of apoptotic bodies containing nuclear fragments were observed in cells treated with 100 µg/ml. The EtOAc fraction of G. epunctata treatment significantly arrested HL-60 cells at the G0/G1 phase (p<0.05) and ROS was significantly elevated as well as the loss of membrane mitochondrial potential in a concentration dependant manner. The results demonstrated that the EtOAc fraction of G. epunctata inhibited the proliferation of HL-60 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to occur through the mitochondrial pathway.

Cytotoxicity and modes of action of four naturally occuring benzophenones: 2,2',5,6'-tetrahydroxybenzophenone, guttiferone E, isogarcinol and isoxanthochymol.

INTRODUCTION: The emergence of drug-resistant cancer cells drastically reduces the efficacy of many antineoplasic agents and, consequently, increases the frequency of therapeutic failure. Benzophenones are known to display many pharmacological properties including cytotoxic activities. The present study was aimed at investigating the cytotoxicity and the modes of action of four naturally occurring benzophenones 2,2',5,6'-tetrahydroxybenzophenone (1), isogarcinol (2), isoxanthochymol (3) and guttiferone E (4) on a panel of eleven cancer cell lines including various sensitive and drug-resistant phenotypes. METHODS: The cytotoxicity of the compounds was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect the activation of caspases 3/7, caspase 8 and caspase 9 in cells treated with compounds 2-4. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells, analysis of mitochondrial membrane potential (MMP) as well as measurement of reactive oxygen species (ROS). RESULTS: The four tested benzophenones inhibited the proliferation of all tested cancer cell lines including sensitive and drug-resistant phenotypes. Collateral sensitivity of cancer cells to compounds 1-4 was generally better than to doxorubicin. Compound 2 showed the best activity with IC50 values below or around 1 µM against HCT116 colon carcinoma cells (p53+/+) (0.86 µM) and leukemia CCRF-CEM (1.38 µM) cell lines. Compounds 2-4 strongly induced apoptosis in CCRF-CEM cells via caspases 3/7, caspase 8 and caspase 9 activation and disruption of MMP. CONCLUSIONS: The studied benzophenones are cytotoxic compounds that deserve more detailed exploration in the future, to develop novel anticancer drugs against sensitive and otherwise drug-resistant phenotypes.

Polyketide metabolites from the endophytic fungus Microdiplodia sp. KS 75-1.

Through our screening for new natural compounds, four new polyketide metabolites, 7,8-dihydonivefuranone A (1), 6(7)-dehydro-8-hydroxyterrefuranone (2), 8-hydroxyterrefuranone (3), and 6-hydroxyterrefuranone (4) were isolated from the fermentation extract of Microdiplodia sp. KS 75-1, together with the known compounds nivefuranones A (5) and B (6); their structures were determined by spectroscopic (NMR, UV and IR) and MS analysis. Compounds 1, 2, 4 and 5 showed antimicrobial activity against Candida albicans and Staphylococcus aureus.

Isopimarane diterpene glycosides, isolated from endophytic fungus Paraconiothyrium sp. MY-42.

Six isopimarane diterpenes, compounds 1-6, were isolated from the endophytic fungus Paraconiothyrium sp. MY-42. Compound 1 possesses a 19-glucopyranosyloxy group. Its structure was first elucidated by spectroscopic data analysis and finally confirmed by X-ray crystallography, whereas structures 2-6 were mainly elucidated based on the analysis of spectroscopic evidence. Compounds 2 and 3 showed moderate cytotoxicities against the human promyelocytic leukemia cell line HL60 (IC50 6.7 µM value for 2 and 9.8 µM for 3).

Cadinane sesquiterpenoids, strobilols L and M, from Strobilurus ohshimae.

Strobilols L and M, which are cadinane sesquiterpene derivatives, were isolated from the liquid culture of the edible mushroom Strobilurus ohshimae. Their structures have been established on the basis of spectral analyses. Strobilols A-M were examined for their growth inhibition activity against human cancer cell lines YMB and COLO 201.

Antifungal abietane-type diterpenes from the cones of Taxodium distichum Rich.

The chemical composition of Taxodium distichum cones and the antifungal activities of twelve diterpenoids against two wood decay fungi, Trametes versicolor (white-rot) and Fomitopsis palustris (brown-rot) were examined. The chemical composition of the major extractive fraction, the n-C(6)H(14) extract, was evaluated and its antifungal properties were identified. Twelve diterpenoids including ten abietane-type components were isolated from the n-C(6)H(14) extract: 6,7-dehydroferruginol (1), ferruginol (2), 6,7-dehydroroyleanone (3), sandaracopimaric acid (4), taxodione (5), taxodal (6), taxodone (7), sugiol (8), xanthoperol (9), salvinolone (10), 5,6-dehydrosugiol (11), and 14-deoxycoleon U (12). Compounds 5 and 12 were highly active against both wood-decay fungi. In particular, the activities of these compounds against F. palustris were potent. The results suggest that the position and the number of hydroxyl groups on abietane-type structures may be related to antifungal activities against T. versicolor and F. palustris.

A novel Aspergillus oryzae esterase that hydrolyzes 4-hydroxybenzoic acid esters.

In this study we report the biochemical characterization of a hypothetical protein from Aspergillus oryzae exhibiting sequence identity with feruloyl esterase and tannase from the genus Aspergillus. The purified recombinant protein showed a hydrolytic activity toward the ethyl, propyl, or butyl esters of 4-hydroxybenzoic acid, but did not show feruloyl esterase or tannase activity. Finally, the enzyme decreased the antimicrobial activity of parabens against A. oryzae via hydrolysis of the ester bond present in butyl 4-hydroxybenzoic acid.