Isolation of two peptaibols with potent antimicrobial and cytotoxic activities from the mangrove endophytic fungus Trichoderma lentiforme ML-P8-2.

Trichorzin PA is a family of 18-residue peptaibols with linear and flexible peptide chains. The three-dimensional structures and biological activities of trichorzin PA peptaibols are largely uncharacterised. In this work, two previously identified peptaibols, trichorzin PA VI (1) and II (2), were isolated from Trichoderma lentiforme ML-P8-2. While for the first time, we report here the X-ray crystallographic structure of 1, antimicrobial activities against a panel of common pathogenic bacteria and fungi, and cytotoxicities of 1 and 2. In bioassays, 1 and 2 exhibited strong antimicrobial activities against the seven tested microbes, with MIC values in the range of 0.19-6.25 µM. Additionally, 1 and 2 displayed potent cytotoxicities against five human cancer cell lines, with IC50 values in the range of 0.01 ± 0.02-2.75 ± 0.17 µM. The bioassay results were generally better than those reported for other 18-residue peptaibols, including other trichorzin PA members.

The Polyketides with Antimicrobial Activities from a Mangrove Endophytic Fungus Trichoderma lentiforme ML-P8-2.

Five new polyketides, including two chromones (1-2), two phenyl derivatives (4-5), and a tandyukusin derivative (6), along with five known polyketides (3 and 7-10) were isolated from mangrove endophytic fungus Trichoderma lentiforme ML-P8-2. The planar structures of compounds were elucidated via detailed 1D, 2D NMR, and HR-ESI-MS analysis. ECD spectra, optical rotation values calculation, and alkali hydrolysis were applied in the determination of the absolute configuration of the new compounds. In bioassays, 6 and 9 exhibited promising antifungal activities against Penicillium italicum, with an MIC value of 6.25 µM for both compounds. Moreover, 3 displayed moderate AChE inhibitory activity with an IC50 value of 20.6 ± 0.3 µM.

Mechanism and Influence of Dispersants on the Action of Polymer Flocculants Used in Slurry Separation.

The application of polymer flocculants plays a pivotal role in the slurry separation process of shields, and the dispersant used for treating cutter mud cakes can significantly impact the effectiveness of polymer flocculants, potentially leading to reduced efficiency in slurry separation. Experiments were conducted to select appropriate flocculants and investigate the influence of dispersants on flocculant effectiveness, aiming to assess the effect of flocculants and explore the relationships and mechanisms governing their influence. Changes in the patterns of slurry flocculation were revealed in terms of flocculation-driven precipitation and vacuum-filtration effects. The purpose of this article is to provide a reference for the field application of polymer flocculants in the shield field. The conclusions are as follows. Inorganic flocculants containing 0.5% polyaluminum chloride (PAC) exhibit the most effective flocculation, demonstrating strong charge neutralization action. Organic flocculants containing 0.1% cationic polyacrylamides (CPAM) exhibit the most effective flocculation, demonstrating strong bridging and net capture effects. The dispersant sodium hexametaphosphate (SHMP) can significantly weaken the charge-neutralizing action of flocculants and slightly enhance bridging and net capture effects. SHMP can impede the flocculation of slurry with PAC. For CPAM, SHMP can enhance the flocculation of slurry at a low mass fraction (0.1% and 0.3%), while SHMP can significantly hinder flocculation at a high mass fraction (0.5% and 1%). A low mass fraction of SHMP reduced slurry viscosity to 246.3 mPa.s and enhanced vacuum filtration, while a high mass fraction of SHMP increased slurry viscosity to 667.2 mPa.s and hindered vacuum filtration. In conclusion, while dispersants reduce the effectiveness of inorganic flocculants at any mass fraction, a small number of dispersants enhances the performance of organic flocculants; thus, the organic flocculant CPAM is recommended for slurry separation.

Chemometric Classification of Apple Cultivars Based on Physicochemical Properties: Raw Material Selection for Processing Applications.

Apple cultivars exhibit significant diversity in fruit quality traits, creating distinct consumption scenarios. This study aimed to assess the physicochemical parameters and sensory attributes differences among fifteen apple cultivars and identify characteristic qualities suitable for various processed apple products using chemometric analysis. Relatively large differences were registered between cultivars for deflection, peel color, titratable acidity (TA), the ratio of total soluble solid to titratable acidity (TSS/TA), hardness, soluble sugar, and volatile organic compound contents. Sensory results showed significant differences existed among the preferences for different processed products. Based on the above results, all cultivars could be distinguished into three main clusters. Cluster I (i.e., Aziteke, Bakeai, Magic Flute, Royal Gala, Red General, Red Delicious, and Zhongqiuwang) demonstrated favorable appearance, high sensory scores, and rich aroma volatile compounds, making them suitable for direct consumption. Cluster II (i.e., Fuburuisi, Sinike, Honglu, and Huashuo) exhibited a higher sugar and acid content, making them suitable for apple juice production. Cluster III (i.e., Miqila, Honey Crisp, Shandong Fuji, and Yanfu 3) were more suitable for fresh-cut apples due to their good flavor and undesirable appearance. Several chemometric analyses effectively assessed differences among apple cultivars.

Cytosporones W and X: Two Mutually Converting Epimers from a Mangrove Endophytic Fungus Diaporthe sp. ZJHJYZ-1.

Two new octaketides, cytosporones W (1) and X (2), along with eight known cytosporone derivatives [(±)-3-9], were isolated from mangrove endophytic fungus Diaporthe sp. ZJHJYZ-1. Compounds 1 and 2 were a pair of epimers, whose configuration of C-1 could mutually convert, causing racemization of the lactone ring. The planar structures of compounds were elucidated through detailed 1D, 2D NMR, and HR-ESI-MS analysis. ECD spectra comparison and modified Mosher ester method were applied to determine the absolute configuration of 1 and 2. In bioassays, (±)-3 exhibited promising inhibitory activities against Bacillus subtilis, Pseudomonas aeruginosa, and Penicillium italicum with MIC, respectively, for 12.5, 12.5, and 3.13 µM.

A novel flavonoid and other constituents from Rubus rosifolius S.Vidal (Rosaceae).

Various reports revealed that chemical constituents from many species of Rubus exhibit diverse biological activities. In this study, a novel flavonoid with a 2-(phenanthren-9-yl)-4H-chromen-4-one structure (1), a 5-phenylthiophene-2-carbaldehyde derivative (5) first isolated from a natural source, together with five known compounds including three polyketides (2-4) and two sesquiterpenoids (6-7) were isolated from a traditional Chinese medicine Rubus rosifolius S.Vidal (Rosaceae). The structures of new compounds were elucidated by detailed spectroscopic analysis including NMR and X-ray single-crystal diffraction. The bioassays results indicated that, compound 1 displayed significant cytotoxicity against human colon cancer cell line HCT116 with IC50 value of 8.6 ± 1.9 µM, and compound 5 exhibited moderate cytotoxicity against human breast cancer cell line MDA-MB-435 with IC50 value of 24.1 ± 0.8 µM.

Hemiacetalmeroterpenoids A-C and Astellolide Q with Antimicrobial Activity from the Marine-Derived Fungus Penicillium sp. N-5.

Four new compounds including three andrastin-type meroterpenoids hemiacetalmeroterpenoids A-C (1-3), and a drimane sesquiterpenoid astellolide Q (15), together with eleven known compounds (4-14) were isolated from the cultures of the marine-derived fungus Penicillium sp. N-5, while compound 14 was first isolated from a natural source. The structures of the new compounds were determined by analysis of detailed spectroscopic data, and the absolute configurations were further decided by a comparison of the experimental and calculated ECD spectra. Hemiacetalmeroterpenoid A (1) possesses a unique and highly congested 6,6,6,6,5,5-hexa-cyclic skeleton. Moreover, the absolute configuration of compound 14 was also reported for the first time. Compounds 1, 5 and 10 exhibited significant antimicrobial activities against Penicillium italicum and Colletrichum gloeosporioides with MIC values ranging from 1.56 to 6.25 µg/mL.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release.

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

Secondary Metabolites with α-Glucosidase Inhibitory Activity from Mangrove Endophytic Fungus Talaromyces sp. CY-3.

Eight new compounds, including two sambutoxin derivatives (1-2), two highly oxygenated cyclopentenones (7-8), four highly oxygenated cyclohexenones (9-12), together with four known sambutoxin derivatives (3-6), were isolated from semimangrove endophytic fungus Talaromyces sp. CY-3, under the guidance of molecular networking. The structures of new isolates were elucidated by analysis of detailed spectroscopic data, ECD spectra, chemical hydrolysis, 13C NMR calculation, and DP4+ analysis. In bioassays, compounds 1-5 displayed better α-glucosidase inhibitory activity than the positive control 1-deoxynojirimycin (IC50 = 80.8 ± 0.3 µM), and the IC50 value was in the range of 12.6 ± 0.9 to 57.3 ± 1.3 µM.