Records of Natural Products

Two new cucurbitane-type triterpenoids (1-2) and one known compound (3) were obtained from the ethyl acetate extract of Trichosanthes kirilowii Maxim. The structures of these compounds were elucidated on the basis of spectroscopic data analysis and comparison with spectroscopic data in the literature. All compounds were evaluated for anti-inflammatory activity in LPS-induced RAW264.7 cells. Compounds 1 and 2 could inhibit the secretion of IL-6, TNF-α, and NO, with IC50 values ranging from 34.82±1.54 to 86.14±1.94 μM

The emergence of multidrug-resistant Candida strains especially, Candida auris, C. dubliniensis, and C. inconspicua has accelerated the research on antifungal novel molecules. Sesquiterpene lactones, abundant in the Asteraceae family, have drawn attention with their antifungal activity. Therefore, three extracts obtained from the aerial part of Turkish endemic Centaurea polypodiifolia were investigated against Candida albicans (ATCC 90028), C. krusei (ATCC 6258), C. dubliniensis (NCPF 3949a), C. inconspicua (NCPF 8523), and C. auris (NCPF 8977) and gave MIC values between 6.25 and 12.5 µg/mL. Dichloromethane (DCM-M) extract yielded five known (cynaropicrin, cynarinin A, aguerin B, grosheimin, and dehydrocynaropicrin) and one novel (nourolide) guaianolide-type sesquiterpene lactones. Two semi-synthetic cynaropicrin derivatives were obtained to enhance the molecular diversity of the present study. 1D (1H and 13C APT) and 2D (COSY, HSQC, HMBC, and NOESY) NMR experiments were employed for structure elucidation. MIC values of the tested sesquiterpene lactones against the above-mentioned strains ranged between 3.12 and 50 µg/mL. Molecular dynamics simulations were conducted to investigate the interaction of 4 (aguerin B), which demonstrated the highest antifungal activity, with the exo-β-(1,3)-glucanase and 14-α-demethylase enzymes. These findings revealed stable binding interactions, suggesting that aguerin B has potential as a lead for further antifungal drug development.

Eight compounds were isolated from the ethyl acetate extract of the Diaporthe phaseolorum fermentation products, comprising five polyketide derivatives (1–5), one chromene (6), one chromone (7), and one tetralone (8). Among these, compounds 1 and 6 were identified as previously undescribed. Notably, compound 6 features a unique C12 chromone skeleton, representing only the second reported example of such a framework. The structures and spatial configurations of all compounds were elucidated through comprehensive analysis of HR-MS, NMR, and quantum chemical calculations supported by DP4+ analysis. In vitro anti-inflammatory activity screening revealed that none of the isolated compounds (1–8) inhibited nitric oxide (NO) production in mononuclear macrophages.

The genus Teucrium L., a member of the Lamiaceae family, is represented by approximately 36 species in Türkiye. In this study, the essential oil composition of the aerial parts of Teucrium kotschyanum Poech collected from ˙Izmir (Ödemi¸s) was investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for the first time. The major compounds were identified as germacrene D (20.0%), α-cadinol (6.9%), β-bourbonene (6.6%), hexadecanoic acid (6.6%), δ-cadinene (5.9%) and manool (4.1%). The antibacterial and antifungal activities of the essential oil were evaluated against six bacteria and six fungi using the microdilution broth method. The essential oil exhibited limited antimicrobial activity, with the highest efficacy observed against Candida utilis (MIC:125 μg/mL) and the lowest against Staphylococcus epidermidis and Salmonella typhimurium (MIC: 2000 μg/mL).