Phytochemistry最新文献

Sixteen undescribed pyrrololactam alkaloids, including five 2-bromopyrrole-ε-lactam (1a, 1b, 4a, 4b and 5), two 3-bromopyrrole-ε-lactam (9 and 10), eight pyrrole-ε-lactam (2a-3 and 6a-8), and one pyrrole-δ-lactam alkaloids (11), along with three previously reported compounds (12–14) were isolated from the marine sponge Phakellia fusca collected in the South China Sea. The planar structures were determined by NMR and MS analyses, while the absolute configurations were clearly elucidated by comparing the experimental and calculated ECD spectra. Compounds 2a, 2b, 4a-7b, 10, 12 and 13 exhibited anti-inflammatory activity in inhibiting the production of inflammatory cytokines IL-6 in LPS-induced RAW264.7 macrophages.

Centella asiatica (L.) Urban is a medical plant rich in triterpenoids, frequently used in Asia to treat skin conditions such as acne. To search for anti-photoaging agents, 16 known triterpenoids and five undescribed triterpenoids, including three ursane, one oleanane and one nor-ursane were isolated from the whole herb of C. asiatica. The structures and relative stereochemistry of these compounds were elucidated by detailed NMR spectra and HRESIMS. Compounds 1 and 2 were isomers of ursane-type and oleane-type triterpenes with rare aldehyde groups on C-23. Compound 4 was a unique example of a nor-ursane type triterpenoid. The Ultraviolet B (UVB) induced HaCaT cell damage model was used to measure the in vitro anti-photoaging activity of all 21 compounds. Twenty compounds significantly increased HaCaT viability and inhibited lactate dehydrogenase (LDH) release after UVB exposure. These findings highlight the protective effects of C. asiatica-derived triterpenoids against UVB damage and indicate their potential as natural agents that can protect the skin against photoaging.

Phytochemical investigation of the 70% ethanol extract of Isodon henryi Kudô afforded fifteen ent-kaurane diterpenoids, including nine previously undescribed compounds, named isohenolides C–K (1–9). Compounds 1–6 featured an unusual 6,7;8,15-diseco-7,20-olide ent-kaurane diterpenoid scaffold, in which 1 also possessed an 11,15-lactone ring while 2–6 all contained a free α-methylene-γ-carboxylic acid. Compound 6 was also a rare 6,8-cyclo-7,20-olide ent-kauranoid. Their structures were elucidated primarily by HRESIMS, 1D and 2D NMR spectroscopy, electronic circular dichroism and X-ray diffraction (Cu Kα) methods. Additionally, most compounds were also screened for anti-inflammatory actions against lipopolysaccharide-induced RAW 264.7 cells, and compounds 9 and 13 exhibited stronger nitric oxide inhibition, with IC₅₀ values of 15.99 ± 0.75 and 18.19 ± 0.42 μM, respectively.

Four previously undescribed phloroglucinols, including three pairs of enantiomers, (±)-rhodotomentodimer F, (±)-rhodotomentodimer G, and (±)-rhodotomentomonomer E, and one phloroglucinol-sesquiterpene meroterpenoid, rhodotomentodione E, together with one previously reported congener, (±)-rhodomyrtosone A, were obtained from the leaves of Rhodomyrtus tomentosa. The structures including absolute configurations of previously undescribed isolates were elucidated by extensive spectroscopic analysis (HRESIMS and NMR), ECD calculations, and single-crystal X-ray diffraction. (±)-Rhodotomentodimer F is a rare phloroglucinol derivative conjugated by a β-triketone moiety and an unprecedented resorcinol unit via the formation of a rare bis-furan ring system, whereas (±)-rhodotomentomonomer E shares a rearranged pentacyclic scaffold. Pharmacologically, (±)-rhodotomentomonomer E showed the strongest human acetylcholinesterase (hAChE) inhibitory effect with an IC₅₀ value of 1.04 ± 0.05 μM. Molecular formula studies revealed that hydrogen bonds formed between hAChE residues Glu202, Ser203, Ala204, Gly121, Gly122, Tyr337, and His447 and (±)-rhodotomentomonomer E played crucial roles in its observed activity. These findings indicated that the leaves of Rhodomyrtus tomentosa can supply a rich source of hAChE inhibitors. These inhibitors might potentially be utilized in the therapeutic strategy for Alzheimer's disease, offering promising candidates for further research and development.

Short rotation coppices (SRCs) represent an important source of biomass. Since they are grown in various mixtures, SRCs represent an excellent opportunity for assessing the effects of local plant neighbourhoods on their performance. We used a common garden experiment consisting of plots that varied in genotype diversity of SRC willows to test for the effects of chemical traits of individual plants and chemical variation in the plots where they grew on insect herbivory. We also explored whether the composition of willows planted in a plot affected their chemistry. To do this, we performed untargeted metabolomics and quantified various chemical traits related to the total set of metabolites we detected, flavonoids, and salicinoids in four willow genotypes. We measured the leaf herbivory that the plants suffered. The genotypes differed in most chemical traits, yet we found only limited effects of individual traits on herbivory damage. Instead, herbivory damage was positively correlated with structural variation in salicinoids in a plot. When analysing the effects of plot chemical variation on herbivory damage separately for each genotype, we found both positive and negative correlations between the two, suggesting both associational resistance and susceptibility. Finally, we also observed a significant effect of the interaction between genotype and plot composition on structural variation in plant chemistry. Overall, our results suggest that high chemical variation in mixed willow SRCs does not necessarily lower the herbivory damage, possibly due to spillover effects of insect herbivores among genotypes. Our results also show that different genotypes respond differently to plot composition in terms of herbivory damage and chemical composition, which may affect their suitability for growing in mixed stands.

Kopsileuconines A−D (1−4), four monoterpenoid bisindole alkaloids with unprecedented skeletons, along with their biosynthetically related precursors (5−8) were isolated from the roots of Kopsia hainanensis. Compound 1 possessed an undescribed C-6−C-5′ dimerization pattern of aspidofractinine-type alkaloids. Compounds 2−4 were rhazinilam-kopsine (2) and rhazinilam-aspidofractinine type (3 and 4) bisindole alkaloids with undescribed skeletons, respectively. Their structures with absolute configurations were fully accomplished by extensive spectroscopic analysis, quantum-chemical calculations, and X-ray crystallography. A plausible biosynthetic pathway for 1−4 was proposed. Compound 2 exhibited a significant inhibitory effect against human lung cancer cell lines PC9 (EGFR mutant), with an IC₅₀ value of 15.07 ± 1.19 μM.

The phytochemical investigation on the pericarps of Garcinia multiflora resulted in the isolation of 12 previously undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs, 1–12) with a variety of skeletons. Their structures were determined by comprehensive spectroscopic analyses, ECD calculations, and single-crystal X-ray diffraction. Compounds 6–9 possess a rare bicyclo[4.3.1]decane skeleton. Additionally, the anti-tumor activity of the 12 isolates was evaluated. The results indicated that compounds 5, 9, and 12 exhibited significant cytotoxicity in a wide range of cancer cell lines, including the human breast cancer MDA-MB-231 cells, human lung cancer A549 cells, human colon cancer SW480 cells and human ovarian cancer HEY cells. Further studies indicated that compound 5 induced cell cycle arrest and apoptosis, to inhibit the growth of MDA-MB-231 cells. Taken together, these findings expand the chemical diversity of PPAPs and further demonstrate the potential of PPAPs as candidates for cancer treatment.

Scoparodane C (1), a diterpenoid with a rare 3,4-seco-3-nor-2,11-epoxy-ent-clerodane scaffold, was obtained from the aerial parts of Isodon scoparius, along with isocopariusines A–E (2–6), five ent-clerodanoids featuring a 5/6-fused ring system, and isocopariusines F–H (7–9), three common ent-clerodanoids. The structures of these previously undescribed compounds were established by a combination of spectroscopic analysis, X-ray diffraction, chemical derivatization, and quantum chemical calculation. Remarkably, isocopariusine B (3) showed strong resistance reversal activity against fluconazole-resistant Candida albicans.

Six pairs of previously undescribed enantiomeric phytocannabinoid-like meroterpenoids, (±)-spinulinoids A‒F, and two naturally occurring compounds, (+)-rhododaurichromanic acid A and (E)-4-((3,7-dimethylocta-2,6-dien-1-yl)oxy)benzoic acid, together with one known congener, (−)-rhododaurichromanic acid A, were obtained from the twigs and leaves of Rhododendron spinuliferum. Their structures were established by their extensive spectral data (NMR and HRESIMS), ECD calculations, and single-crystal X-ray diffraction data. Spinulinoids A and B are unprecedented phytocannabinoid-like meroterpenoids constructed by the resorcinol moiety and a β-bisabolene unit, whereas spinulinoid C represents a rare adduct of quinone and β-bisabolene with a tricyclic 6/6/6 ring system.

Nine previously unreported lathyrane diterpenoids named euphorantesters A−I, along with 16 known analogues, have been separated from the tubers of Euphorbia antiquorum. Their structures were established by means of spectroscopic analyses, time-dependent density functional theory based electronic circular dichroism calculation and single crystal X-ray crystallography. Their reversal ability against P-glycoprotein-mediated multidrug resistance (MDR) in MCF-7/ADR cell line was then evaluated, and 15 ones exhibited moderate MDR reversal activity with reversal fold falling in the range of 1.12–13.15. The most active euphorantester B could effectively increase the sensitivity of MCF-7/ADR cell to adriamycin comparably to the reference drug verapamil.