Records of Natural Products

Phlomis pungens Willd. (syn. Phlomis herba-venti subsp. pungens (Willd.) Maire ex DeFilipps) is a medicinal and aromatic species that has been studied mainly for its essential oil composition, whereas its non-volatile phytochemical constituents have remained largely unexplored. In this study, the ethanolic extract of P. pungens was  systematically characterized for the first time using a targeted LC–MS/MS method. In parallel, total phenolic and flavonoid contents, antioxidant potential, and multi-enzyme inhibitory activities were evaluated. LC–MS/MS profiling revealed a phenolic acid–rich composition, with quinic acid (14.146 mg/g extract) and chlorogenic acid (13.187 mg/g) identified as the predominant compounds.These were followed by cynaroside (1.541 mg/g), vanillic acid (1.453 mg/g), and cosmosiin (0.830 mg/g). The extract demonstrated considerable levels of total phenolics and flavonoids (37.18 ± 1.97 μg PEs/mg and 18.19 ± 0.90 μg QEs/mg extract, respectively). Antioxidant evaluation indicated moderate activity, particularly in the ABTS (IC50 = 32.05 ± 0.28 μg/mL) and CUPRAC (A0.5 = 20.83 ± 0.37 μg/mL) assays. Enzyme inhibition studies revealed selective inhibitory effects against collagenase (24.73 ± 0.32%), tyrosinase (15.04 ± 0.11%), and butyrylcholinesterase (13.62 ± 0.12%) at 50 μg/mL, while no inhibition was detected toward acetylcholinesterase, urease, or elastase.These findings suggest that the biological activities of P. pungens may be associated with its non-volatile phenolic constituents.This work provides novel phytochemical data and highlights the potential of the species for future pharmaceutical and dermocosmetic applications.

Cultured lichen mycobionts have been considered as valuable sources of natural compounds with unique structure scaffolds. Nigrovothelium inspersotropicum, a crustose lichen from the family Trypetheliaceae, is an indigenous species in Vietnam. However, there is a scarcity of chemical and biological information available regarding N. inspersotropicum and its cultured mycobionts. In this study, the mycobiont of N. inspersotropicum was cultivated and subjected to chemical and biological investigations. As a result, six compounds, including 3,4-dihydro-7,8-dihydroxy-6-methoxy-3-methylisocoumarin (1), (+)-(3S)-6,7-dimethoxymellein  (2), 8-hydroxy-6,7-dimethoxyisocoumarin (3), aspermytin A (4), subnudatone B (5), and b-sitosterol (6), were isolated and structurally elucidated using extensive spectroscopic analyses (1D- and 2D-NMR and HRESIMS). Notably, compound 1 is new compound, while compound 2 is identified as a new natural compound. The isolated compounds were evaluated for their inhibitory activities against alpha-glucosidase, nitric oxide production, SARS-CoV-2 Mpro, and HIV-1 reverse transcriptase. In summary, this study presents new information on natural compounds derived from the mycobiont of N. inspersotropicum and their promising anti-inflammatory, antihyperglycemic, and antiviral activities.

An in-depth investigation into the chemical constituents of Streptomyces ardesiacus GXIMD 03502, a strain known to produce 2-hydroxyphenylthiazoline derivatives, resulted in the isolation of a new α-pyrone compound, germicidin T (1), together with six known compounds (2–7). Their structures were elucidated using comprehensive spectroscopic analyses. The germicidin biosynthetic gene cluster was identified in the genome of this strain. Notably, ORF 17, a type III polyketide synthase (Germicidin synthase, GCS), was found to utilize trimethylmalonyl-ACP as a starter unit in the biosynthesis of compound 1. Based on this finding, the biosynthetic pathway for compounds 1–7 is proposed. Bioactivity evaluation revealed that all compounds exhibited weak toxicity against Artemia salina, while compounds 3 and 7 showed moderate anti-inflammatory activity.

 A previously uncharacterized 3,4-seco-labdane diterpenoid, which is designated Callinudin A (1), along with two known diterpenoids of the same type (2, 3), was isolated from Callicarpa nudiflora leaves. Multiple spectroscopic techniques and literature comparisons were used to elucidate the structures of these compounds. Furthermore, these compounds were tested in vitro to assess their effects on the NLRP3 inflammasome in lipopolysaccharide (LPS)-induced THP-1 macrophages. Analysis revealed that these compounds exhibit inhibitory effects on the NLRP3 inflammasome.