Structures and Biological Activities of Secondary Metabolites from Xylaria spp.

The fungus genus Xylaria is an important source of drug discoveries in scientific fields and in the pharmaceutical industry due to its potential to produce a variety of structured novel and bioactive secondary metabolites. This review prioritizes the structures of the secondary metabolites of Xylaria spp. from 1994 to January 2024 and their relevant biological activities. A total of 445 new compounds, including terpenoids, nitrogen-containing compounds, polyketides, lactones, and other classes, are presented in this review. Remarkably, among these compounds, 177 compounds show various biological activities, including cytotoxic, antimicrobial, anti-inflammatory, antifungal, immunosuppressive, and enzyme-inhibitory activities. This paper will guide further investigations into the structures of novel and potent active natural products derived from Xylaria and their potential contributions to the future development of new natural drug products in the agricultural and medicinal fields.

Bioactive polyketides and meroterpenoids from the mangrove-derived fungus Talaromyces flavus TGGP35.

Six new polyketides, which includes three new lactones (talarotones A-C) (1-3), one new polyketide (talarotide A) (4), two new polyenes (talaroyenes A, B) (5, 6), together with one new meroterpenoid (talaropenoid A) (7) and 13 known compounds (8-20) were isolated from the mangrove-derived fungus Talaromyces flavus TGGP35. The structure and configuration of the compounds 1-7 were elucidated from the data obtained from HR-ESI-MS, IR, 1D/2D NMR spectroscopy, Mo2 (OAc)4-induced electronic circular dichroism (ECD), CD spectroscopy, and modified Mosher's method. Compounds 5 and 20 displayed antioxidant activity with IC50 values of 0.40 and 1.36 mM, respectively. Compounds 3, 6, 11, 16, and 17 displayed cytotoxic activity against human cancer cells Hela, A549, and had IC50 values ranging from 28.89 to 62.23 µM. Compounds 7, 10-12, and 14-18 exhibited moderate or potent anti-insect activity against newly hatched larvae of Helicoverpa armigera Hubner, with IC50 values in the range 50-200 µg/mL. Compound 18 showed antibacterial activity against Ralstonia solanacearum with the MIC value of 50 µg/mL.

Talaromarins A-F: Six New Isocoumarins from Mangrove-Derived Fungus Talaromyces flavus TGGP35.

Six new isocoumarin derivative talaromarins A-F (1-6), along with 17 known analogues (7-23), were isolated from the mangrove-derived fungus Talaromyces flavus (Eurotiales: Trichocomaceae) TGGP35. Their structures were identified by detailed IR, UV, 1D/2D NMR and HR-ESI-MS spectra. The absolute configurations of new compounds were determined by the modified Mosher's method and a comparison of their CD spectra with dihydroisocoumarins described in the literature. The antioxidant, antibacterial, anti-phytopathogenic and inhibitory activity against α-glucosidase of all the isolated compounds were tested. Compounds 6-11, 17-19 and 21-22 showed similar or better antioxidant activity than the IC50 values ranging from 0.009 to 0.27 mM, compared with the positive control trolox (IC50 = 0.29 mM). Compounds 10, 18, 21 and 23 exhibited strong inhibitory activities against α-glucosidase with IC50 values ranging from 0.10 to 0.62 mM, while the positive control acarbose had an IC50 value of 0.5 mM. All compounds showed no antibacterial or anti-phytopathogenic activity at the concentrations of 50 µg/mL and 1 mg/mL, respectively. These results indicated that isocoumarins will be useful to developing antioxidants and as diabetes control agents.

Construction and Screening of Fractional Library of Salviae Miltiorrhizae Radix et Rhizoma for the Rapid Identification of Active Compounds against Prostate Cancer.

Efficient screening of anticancer agents is in urgent need to develop new drugs that combat malignant tumors and drug resistance. In this study, a combined strategy composed by solvent partition and HPLC fractionation was developed to generate an herbal fraction library of Salviae Miltiorrhizae Radix et Rhizoma to quickly and efficiently screen anticancer agents. All library entries are directed into 96 well plates which are well mapped with HPLC chromatograms. The cell proliferation assay revealed seven active subfractions. Then, the major active ten peaks in these subfractions were prepared and isolated by semipreparative HPLC, and their inhibitory activities against prostate cancer cells were then tested at the same concentration level, leading to the identification of several active compounds. In addition, the structures of compounds arucadiol (2), 15,16-dihydrotanshinone I (4), methyl tanshinonate (5), cryptanshinone (7), 1,2-dihydrotanshinquinone I (9), and tanshinone IIA (10) were characterized by mass spectrometry and X-ray crystallographic analysis, and they were confirmed to be active in suppressing prostate cancer cell proliferation at 7.5 or 15 µg/mL, among which, the minor compounds 2, 4, and 5 showed higher activities than 9 and 10. This study provided a rapid strategy of identifying new anticancer agents in Salviae Miltiorrhizae Radix et Rhizoma, which can be applied in other herbal medicines.

Bioactive isocoumarins isolated from a mangrove-derived fungus Penicillium sp. MGP11.

Two new isocoumarins penicimarins L-M (1-2), along with seven known analogues (3-9) were isolated from the mangrove-derived fungus Penicillium sp. MGP11. Compounds 1-2 were established by spectroscopic methods and comparison of their circular dichroism (CD) spectra with the literature. All isolated compounds were evaluated for antioxidant and α-glucosidase inhibitory activities. Compound 8 had better antioxidant activity (IC50 = 4.6 µM) than positive control trolox (IC50 = 12.9 µM). Compounds 5, 8 and 9 exhibited α-glucosidase inhibitory activity with the IC50 values of 776.5, 683.7 and 868.7 µM, respectively.[Formula: see text].

A new bioactive isocoumarin from the mangrove-derived fungus Penicillium sp. TGM112.

A new isocoumarin, penicimarin N (1), along with five known compounds (2-6), were isolated from the mangrove-derived fungus Penicillium sp. TGM112. The structure of 1 was elucidated on the basis of extensive spectroscopic data analysis, and the absolute configuration of 1 was determined by comparison of their circular dichroism (CD) spectra with the literature. The structures of known compounds were determined by comparison with the literature data. All the isolated compounds were examined for their antioxidant and α-glucosidase activities. Compound 1 showed strong antioxidant activity with the IC50 value of 1.0 mM, and 1 also exhibited moderate inhibitory activity against α-glucosidase with the IC50 value of 620 µM.

A new phenol derivative isolated from mangrove-derived fungus Eupenicillium sp. HJ002.

A new phenol derivative, 3-chloro-5-hydroxy-4-methoxyphenylacetic acid methyl ester (1), along with five known compounds methyl 4-hydroxyphenylacetate (2), cytosporone B (3), (R)-striatisporolide A (4), (R)-butanedioic acid (5) and ergosterol (6) were isolated from the mangrove-derived fungus Eupenicillium sp. HJ002. Their structures were established by spectroscopic methods, GIAO based 13C NMR chemical shift calculations and comparison with the data of literature. Compounds 1-5 were isolated from Xylocarpus granatum Koening-derived fungus for the first time.

One new α,ß-unsaturated 7-ketone sterol from the mangrove-derived fungus Phomopsis sp.MGF222.

A new α,ß-unsaturated 7-ketone sterol, 5ß,6ß-epoxy-3ß, 15α-dihydroxy-(22E,24R)-ergosta-8(14),22-dien-7-one (1), along with five known sterone derivatives, 5ß,6ß-epoxy-3ß,7α-dihydroxy-(22E,24R)-ergosta-8(14),22-dien-15-one (2), 5ß,6ß-epoxy-3ß,7α,9α-trihydroxy-(22E,24R)-ergosta-8(14),22-dien-15-one (3), 3ß,9α,15α-trihydroxy-(22E,24R)-10(5→4)-abeo-ergosta-6,8(14),22-trien-5-one (4), 3,15-dihydroxyl-(22E,24R)-ergosta-5,8(14),22-trien-7-one (5) and (22E,24R)-ergosta-4,6,8(14),22-tetraen-3,15-dione (6) were isolated from the mangrove-derived fungus Phomopsis sp. MGF222. Their structures were established on the basis of extensive spectroscopic data and comparison with the data of literature. Compound 2 showed weak antibacterial activity against Micrococcus tenuis with the MIC value of 28.2 (±0.52) µM. Compound 5 exhibited moderate antibacterial activity against Staphylococcus aureus with the MIC value of 14.6 (±0.47) µM.

Bioactive Secondary Metabolites from the Culture of the Mangrove-Derived Fungus Daldinia eschscholtzii HJ004.

Two new polyketides, 8-O-methylnodulisporin F (1) and nodulisporin H (2), two new naphthoquinones, 5-hydroxy-2-methoxy-6,7-dimethyl-1,4-naphthoquinone (3) and 5-hydroxy-2-methoxynaphtho[9-c]furan-1,4-dione (4), and a new naphthofuran 1,3,8-trimethoxynaphtho[9-c]furan (5), along with five known compounds 4-O-methyl eleutherol (6), 2-acetyl-7-methoxybenzofuran (7), (-)-orthosporin (8), diaporthin (9), and 6-hydroxymellein (10), were obtained from the EtOAc extract of the mangrove-derived fungus Daldinia eschscholtzii HJ004. The structures of the isolated compounds were elucidated by extensive NMR and MS analyses, while the absolute configurations of the stereogenic carbons were established based on experimental and calculated electronic circular dichroism spectra. Compounds 4 and 7 displayed a potent inhibitory activity against α-glucosidase with the IC50 values of 5.7 and 1.1 µg/mL, respectively. Compounds 1 and 2 showed a moderate antibacterial activity against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Bacillus cereus, with minimum inhibitory concentration (MIC) values ranging from 6.25 to 12.5 µg/mL. Compound 3 exhibited antibacterial activity against B. cereus with the MIC value of 12.5 µg/mL.

Bioactive Polyketide Derivatives from the Mangrove-Derived Fungus Daldinia eschscholtzii HJ004.

Five new tetralones, daldiniones A-E (1-5), three new chromones, 7-hydroxy-5-methoxy-2,3-dimethylchromone (9), 5-methoxy-2-propylchromone (10), and 7-ethyl-8-hydroxy-6-methoxy-2,3-dimethylchromone (11), and two new lactones, helicascolides D and E (16 and 17), together with nine known metabolites (6-8, 12-15, and 18-19) were isolated from the mangrove-derived fungus Daldinia eschscholtzii HJ004. The structures and absolute configurations of the new compounds were determined by analyzing MS and NMR data and utilizing GIAO based 13C NMR chemical shift calculations and quantum chemical electronic circular dichroism (ECD) calculations. Compounds 9, 13, and 18 showed inhibitory activities against α-glucosidase with IC50 values of 13, 15, and 16 µM, respectively.

Bioactive Lactones from the Mangrove-Derived Fungus Penicillium sp. TGM112.

Three new lactones penicilactones A-C (1-3) were obtained from the mangrove-derived fungus Penicillium sp. TGM112. Their structures and absolute configurations were determined by detailed NMR, MS spectroscopic data, Mo2(OAc)4-induced electronic circular dichroism (ECD), and circular dichroism (CD) spectroscopy. Compound 1 showed antibacterial activity against Staphylococcus aureus with an MIC value of 6.25 µg/mL. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with the LC50 value of 78.5 (±0.58) µg/mL.

Bioactive Meroterpenoids and Isocoumarins from the Mangrove-Derived Fungus Penicillium sp. TGM112.

Two new meroterpenoids, penicianstinoids A and B (1 and 2), and eight new isocoumarins, peniciisocoumarins A-H (3-10), together with 10 known analogues (11-20) were obtained from the mangrove-derived fungus Penicillium sp. TGM112. The structures and absolute configurations of 1-10 were determined by interpretation of detailed NMR, MS spectroscopic data, X-ray diffraction analyses, modified Mosher's method, and calculated electronic circular dichroism data. Compounds 1-4, 7, 8, 10, 12, 13, and 16 showed growth inhibition activity against newly hatched larvae of Helicoverpa armigera Hubner with IC50 values ranging from 50 to 200 µg/mL, respectively. Compounds 1, 2, and 11-15 displayed activity against Caenorhabditis elegans with EC50 values ranging from 9.4 (± 1.0) to 38.2 (± 0.6) µg/mL, respectively. Compound 1 represents an austinoid-like meroterpenoid that is reported here for the second time, in which a carbon-carbon double bond was oxidized to a carbonyl group at C-1'-C-2'.

Bioactive cytosporone derivatives isolated from the mangrove-derived fungus Dothiorella sp. ML002.

Three new cytosporone derivatives dothiorelones K-M (1, 2 and 7), together with six known ones (3-6, 8 and 9) were isolated from the mangrove-derived fungus Dothiorella sp. ML002. Their structures were determined by comprehensive 1D, 2D NMR spectroscopic and HR-ESI-MS spectroscopic data. Compounds 1, 2 and 5 displayed inhibitory activities against α-glucosidase with the IC50 values of 22.0, 77.9 and 5.4 µg/mL, respectively. Additionally, compounds 1, 2, and 5 also exhibited antibacterial activities against Staphylococcus aureus (ATCC 6538) with the same MIC values of 50 µg/mL, respectively. The results indicated that cytosporone derivatives will be useful to as diabetes control agents.

Two new benzophenones and one new natural amide alkaloid isolated from a mangrove-derived Fungus Penicillium citrinum.

Two new compounds penibenzophenones A-B (1-2), and the synthetic α,ß-unsaturated amide alkaloid (E)-tert-butyl(3-cinnamamidopropyl)carbamate (4), newly identified as a natural product, alone with three known ones (3, 5-6) were isolated from the EtOAc extract of the endophytic fungus Penicillium citrinum HL-5126 isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Compound 1 was a chlorinated benzophenone. The structures of 1-6 were elucidated by extensive NMR spectral interpretation, MS data and X-ray analysis. The new compound 2 displayed cytotoxic activity against human A549 cell lines with an IC50 value of 15.7 µg/mL, and 1 showed antibacterial activity against Staphylococcus aureus with a MIC value of 20 µg/mL.

Penicilindoles A-C, Cytotoxic Indole Diterpenes from the Mangrove-Derived Fungus Eupenicillium sp. HJ002.

Three new indole diterpenes, penicilindoles A-C (1-3), were isolated from the mangrove-derived fungus Eupenicillium sp. HJ002. Their planar structures and absolute configurations were determined by interpretation of NMR spectroscopic data, HR-ESIMS, and X-ray diffraction analysis using Cu Kα radiation. The cytotoxic and antibacterial activities were evaluated in vitro; penicilindole A (1) showed cytotoxic activity against human A549 and HepG2 cell lines with IC50 values of 5.5 and 1.5 µM, respectively.

One new cytochalasin metabolite isolated from a mangrove-derived fungus Daldinia eschscholtzii HJ001.

One new cytochalasin metabolite [11]-cytochalasa-5(6),13-diene-1,21-dione-7,18-dihydroxy-16,18-dimethyl-10-phenyl-(7S*,13E,16S*,18R*) (1), together with three known compounds (2-4) were obtained from the EtOAc extract of the endophytic fungus Daldinia eschscholtzii HJ001 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1 and 2 were evaluated for their antibacterial and cytotoxic activities.

New chlorinated xanthone and anthraquinone produced by a mangrove-derived fungus Penicillium citrinum HL-5126.

Two new chlorinated metabolites 4-chloro-1-hydroxy-3-methoxy-6-methyl-8-methoxycarbonyl-xanthen-9-one (1) and 2'-acetoxy-7-chlorocitreorosein (2), together with three known compounds (3-5), were obtained from the EtOAc extract of the endophytic fungus Penicillium citrinum HL-5126 isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All compounds were evaluated for their antibacterial and topoisomerase I inhibitory activities. Compound 2 exhibited antibacterial activity against Vibrio parahaemolyticus with an MIC value of 10 µm.

Dihydroisocoumarins from the Mangrove-Derived Fungus Penicillium citrinum.

Three new dihydroisocoumarin penicimarins G-I (1-3), together with one known dihydroisocoumarin (4) and three known meroterpenoids (5-7), were obtained from a fungus Penicillium citrinum isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of spectroscopic data. The absolute configuration of 1 was determined by the X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of 2 and 3 were determined by comparison of their circular dichroism (CD) spectra with the literature. All compounds were evaluated for their antibacterial activities and cytotoxic activities.

A new benzopyrans derivatives from a mangrove-derived fungus Penicillium citrinum from the South China Sea.

One new benzopyran derivative (2R(*),4R(*))-3,4-dihydro-5-methoxy-2-methyl-2H-1-benzopyran-4-ol (1), together with five known compounds (2-6), were obtained from the EtOAc extract of the endophytic fungus Penicillium citrinum HL-5126 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. All compounds were evaluated for their antibacterial activities. Compound 6 exhibited potent inhibitory activity against Bacillus subtilis, Bacillus cereus and Micrococcus tetragenus with the same MIC values of 6.94 µM.

Application of Carbon-Microsphere-Modified Electrodes for Electrochemistry of Hemoglobin and Electrocatalytic Sensing of Trichloroacetic Acid.

By using the hydrothermal method, carbon microspheres (CMS) were fabricated and used for electrode modification. The characteristics of CMS were investigated using various techniques. The biocompatible sensing platform was built by immobilizing hemoglobin (Hb) on the micrometer-sized CMS-modified electrode with a layer of chitosan membrane. On the cyclic voltammogram, a couple of quasi-reversible cathodic and anodic peaks appeared, showing that direct electrochemistry of Hb with the working electrode was achieved. The catalytic reduction peak currents of the bioelectrode to trichloroacetic acid was established in the linear range of 2.0~70.0 mmol·L(-1) accompanied by a detection limit of 0.30 mmol·L(-1) (3σ). The modified electrode displayed favorable sensitivity, good reproducibility and stability, which suggests that CMS is promising for fabricating third-generation bioelectrochemical sensors.