SpecDis: quantifying the comparison of calculated and experimental electronic circular dichroism spectra

Antiviral miliusanes and isolation of an unprecedented miliusane dimer from Miliusa balansae

In an extensive screening endeavor for anti-coronaviral compounds, we examined 824 tropical plant extracts from the Annonaceae and Rutaceae families. The screening identified an ethyl acetate extract from the aerial parts of Miliusa balansae for its potent inhibitory activity against Human coronavirus HCoV-229E. Subsequent bioassay-guided fractionation of this extract revealed two unreported miliusanes including a complex dimeric structure and seven known compounds, comprising miliusane XXXVI, (+)-miliusol, bistyryls, styryl-pyranones, and the flavonoid rhamnetin. The absolute configuration of the new dimeric miliusane was determined by X-ray crystallography and a putative biogenetic origin was proposed. Investigation of the antiviral effect of these nine phytochemicals within HCoV-229E-infected Huh-7 cells showed that (+)-miliusol and miliusane XXXVI exert antiviral activity at non-cytotoxic concentrations, with IC50 values of 1.15 μM and 19.20 μM, respectively. Furthermore, these compounds significantly inhibited SARS-CoV-2 infection in Vero cells, presenting IC50 values of 11.31 μM for (+)-miliusol and 17.92 μM for miliusane XXXVI. Additionally, both compounds exhibited a potent antiviral effect against the emergent mosquito-borne Zika virus, with IC50 values of 1.34 μM and 23.45 μM, respectively. Time-of-addition assays suggest that their mechanism of action might target later stages of the viral cycle, indicating potential modulation of specific cellular pathways. These findings reinforce the invaluable contribution of medicinal flora as reservoirs of natural antiviral agents and emphasize their prospective role in combatting viruses of medical interest.

Germacrane-type sesquiterpenes from Pilea cavaleriei Levl. subsp. cavaleriei

The first systematic investigation of germacrane-type sesquiterpenes from Pilea cavaleriei Levl. subsp. cavaleriei was conducted. Eleven undescribed germacrane analogues named cavalinols A-K were identified. Their planar structures were determined by extensive analysis of 1D and 2D NMR spectroscopic data, and the absolute configurations were further determined by X-ray single crystal diffraction, Mosher method, and time dependent density functional theory (TDDFT) electron circular dichroism (ECD) calculation, with the aid from DFT NMR calculation and NOESY experiment. Except for the common 10-memebered ring, ten new compounds contained a p-coumaroyl sidechain connected to C-8 of the nucleus skeleton. All the isolated compounds were screened for anti-inflammatory activity in LPS stimulated RAW 264.7 cells, and compounds 5 and 6 showed moderate activity.

Targeted discovery of unusual diterpenoids with anti-fungal activity from the root of Euphorbia lathyris

Lathyrisone A (1), a diterpene with an undescribed tricyclic 6/6/6 fused carbon skeleton, along with spirolathyrisins B-D (3-5), three diterpenes with a rare [4.5.0] spirocyclic carbon skeleton, and one known compound (2) were isolated from the roots of Euphorbia lathyris. Their chemical structures were characterized by extensive spectroscopic analysis, X-ray crystallography, ECD and quantum chemistry calculation. A plausible biosynthetic pathway for compounds 1-5 was proposed, which suggested it is a competitive pathway for ingenol biosynthesis in the plant. The anti-fungal activities of these compounds were tested, especially, compound 2 showed stronger anti-fungal activities against Fusarium oxysporum and Alternaria alternata than the positive control fungicide thiophanate-methyl. The preliminary structure-activity relationship of compounds 1-5 was also discussed. These results not only expanded the chemical diversities of E. lathyris, but also provided a lead compound for the control of plant pathogens.

Monoterpene-chalcone conjugates and diarylheptanoids isolated from the seeds of Alpinia katsumadai Hayata with cytotoxic activity

Five undescribed monoterpene-chalcone conjugates (1-5), one undescribed hypothetical precursor of diarylheptanoid (6), two undescribed diarylheptanoids (7-8), and fourteen known compounds (9-22) were isolated from the seeds of Alpinia katsumadai. Their structures were elucidated through the interpretation of HRESIMS, NMR, ECD, and X-ray diffraction data. MTT assays on human cancer cell lines (HepG2, A549, SGC7901, and SW480) revealed that compounds 3-8, 11, and 13 exhibited broad-spectrum antiproliferative activities with IC50 values ranging from 3.59 to 21.78 μM. B cell lymphoma 2 was predicted as the target of sumadain C (11) by network pharmacology and verified by homogeneous time-resolved fluorescence assay and molecular docking.

Chalcone-Monoterpene Derivatives from the Buds of Cleistocalyx operculatus and Their Potential as Protein Tyrosine Phosphatase 1B Inhibitors

Four new compounds, racemic chalcone-monoterpene hybrids (1-3) and a chalcone (9), along with nine known compounds (4-8, 10-13), have been isolated from the buds of Cleistocalyx operculatus. The chemical structures of the isolated compounds were identified through NMR data analysis and confirmed by computational methods, including electronic circular dichroism (ECD) calculations, and further synthetic approaches. Compounds 1-5 were synthesized via a Diels-Alder reaction, a process informed by biomimetic condensation studies that combined chalcones and monoterpenes. These synthetic approaches also yielded various unnatural chalcone-monoterpene derivatives (14-23). The inhibitory effects on protein tyrosine phosphatase 1B (PTP1B) of both naturally isolated and synthetically obtained compounds were evaluated. Compounds 4, 9, 13, and 16b exhibited potent PTP1B inhibitory activity, with IC50 values ranging from 0.9 ± 0.2 to 3.9 ± 0.7 μM. The enantiomers (+)-4 and (-)-16b showed enhanced activity compared to their respective enantiomers. Kinetic studies indicate that all active compounds inhibit PTP1B through mixed mechanisms, and molecular docking simulations agree with the experimental assays on PTP1B. Our results suggest that chalcone-meroterpene adducts from the buds of C. operculatus exhibit potential as antidiabetic agents, partly due to their PTP1B enzyme inhibition.

Discriminating Clockwise and Counterclockwise Photoisomerization Paths in Achiral Photoswitches by Excited-State Electronic Circular Dichroism

Despite the numerous investigations of photoisomerization reactions from both the computational and experimental points of view, even in complex environments, to date there is no direct demonstration of the direction of rotation of the retinal chromophore, initiating the vision process in several organisms, occurring upon light irradiation. In the literature, many proposals have been formulated to shed light on the details of this process, most of which are extracted from semiclassical simulations. Although high hopes are held in the development of time-resolved X-ray spectroscopy, I argue in this work that simpler but less known techniques can be used to unravel the details of this fascinating photochemical process. In fact, chiroptical spectroscopy would unambiguously prove the direction of the rotatory motion of the chromophore during the photoisomerization process by probing excited state chirality, a piece of information that, so far, has been exclusively extracted from atomistic simulations. I demonstrate this statement by computing the expected chiroptical response along photoisomerization pathways for several models of the retinal chromophores that are found in nature bound to rhodopsins, including nuclear ensemble spectra from semiclassical dynamics simulations, that can be compared with time-resolved experiments.

Anti-inflammatory Lindenane Sesquiterpene Dimers from the Roots of Chloranthus fortunei

In this study, eight lindenane-type sesquiterpene dimers, including five previously undescribed sesquiterpene dimers (1-5), were isolated from the roots of Chloranthus fortunei, and their structures were elucidated using 1D/2D NMR, HRESIMS, and ECD calculations. Compound 1 presents the second example of a type of novel 8,9-seco lindenane-type sesquiterpene dimer, considered a product of 8/9-diketone oxidation. Compounds 2 and 3 represent the third and fourth examples, respectively, of this kind of C-11 methine dimer. Furthermore, compound 4 was considered as an artifact generated from the radical reaction of a known compound chlojaponilide F (6), which was explained by the density functional theory quantum calculation. All isolates were evaluated for their protective activity against the LPS-induced pulmonary epithelial cell line with compound 7 exhibiting the most potent bioactivity. Further in vitro biological evaluation demonstrated that 7 reduced the production of reactive oxygen species and interleukin-1β, further regulated by the expression of the NLRP3. These results show that compound 7 exhibits therapeutic potential for lung inflammatory diseases.

Four new homoisoflavonoids from Caesalpinia pulcherrima

Four new homoisoflavonoids, 7-hydroxy-3-[hydroxy(4'-methoxyphenyl)methyl]-benzopyran-4-one (1), (3R)-7, 8-dihydroxy-3-(4'-methoxybenzyl)-chroman-4-one (2), 7-hydroxy-3-(2'-hydroxy-4'-methoxybenzyl)-chroman-4-one (3), and 7-hydroxy-3-(2'-hydroxy-4'-methoxybenzyl)-benzopyran-4-one (4), were isolated from the seeds of Caesalpinia pulcherrima. The structures of new compounds were elucidated by MS and NMR spectra. Their absolute configurations were assigned using electronic circular dichroism spectrum. Compounds 2 and 4 exhibited cytotoxic effects on MCF-7/TAM cells with the IC50 values of 101.4 ± 0.03 and 93.02 ± 0.03 μM, respectively.

Laburnicolamine: A Rare Penillic Acid Congener from the Nematode Cyst-Associated Fungus Laburnicola nematophila

A chemical investigation of a methanol extract derived from a solid-state rice culture of the nematode-cyst associated fungus Laburnicola nematophila K01 led to the isolation and characterization of a previously undescribed penillic acid analogue named laburnicolamine (1). The chemical structure was elucidated through comprehensive 1D and 2D NMR spectroscopic analyses in methanol-d4 and DMSO-d6, alongside with HR-ESI-MS spectrometry. The absolute configuration of 1 was concluded through the electronic circular dichroism (ECD) and time-dependent density functional theory-ECD (TDDFT-ECD) computations compared to its acquired spectrum. Biological assays revealed that compound 1 exhibited no significant cytotoxic, antimicrobial, or nematicidal activity.

Crotonoids A-H, Labdane-Type Diterpenoids with Anti-Inflammatory Activity from Croton Sublyratus

Croton sublyratus (Euphorbiaceae) is a traditional medicinal plant used by the Thai populace to treat helminthic infections and dermatologic conditions. In present study, eight new labdane-type diterpenoids, crotonoids A-H (1-8) and one known analogue (9) were isolated from the aerial parts of C. sublyratus. Compounds 6 and 7 belong to the rare class of 14,15-dinor-labdane diterpenoids. Compound 8 exhibited a rare 14,15,17-trinor-labdane skeleton. The structures of all these diterpenoids were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Compound 9 exhibited moderate anti-inflammatory activity via the inhibition of NO production in lipopolysaccharide-induced RAW 264.7 cells.

Two pairs of new isobenzofuranone enantiomers from a soil-derived fungus Penicillium canescens DWS225

Two pairs of new isobenzofuranone derivative enantiomers, (±)-penicifurans E (1) and (±)-penicifurans F (2), together with four know compounds (3-6) were isolated from the solid fermentation of Penicillium canescens DWS225. The structures of these enantiomers were elucidated by extensive NMR spectroscopic data, and their absolute configurations were assigned by the experimental and calculated ECD data. The neuroprotective effects of all the isolates against oxygen-glucose deprivation/reperfusion injury in pheochromocytoma-12 cells (PC12) were investigated.

Four new phenolic constituents from root barks of Paeonia ostii

The Paeonia ostii, also known as "Feng Dan" have a crucial role in folk medicine to treat lumbar muscles strain, knee osteoarthritis and cervical spondylosis. In this study, four new phenolic compounds, specifically Paeoniaostiph A-E (1-4) phenolic compounds were characterised through spectroscopic techniques, including 1D and 2D NMR, HRESIMS, UV, IR, and electronic circular dichroism computations to explore their structures. Cytotoxicity and NO production inhibition of the new phenolic compounds were also studied. The results of the cytotoxicity experiment showed that compound 1 is cytotoxic to two human cancer cell lines with IC50 values ranging from 13.3 to 13.5 μM. Compounds 1 and 2 showed certain inhibitory activity on NO production. This is the first report on isolating the components from natural sources.

Sesquiterpenoids from Carpesium abrotanoides and their anti-inflammatory activity both in vitro and in vivo

Twenty-nine sesquiterpenoids, including pseudoguaiane-type (1-11), eudesmane-type (12-23), and carabrane-type (24-29), have been identified from the plant Carpesium abrotanoides. Of them, compounds 1-4, 12-15, and 24-27, namely carpabrotins A-L, are twelve previously undescribed ones. Compound 3 possessed a pseudoguaiane backbone with a rearrangement modification at C-11, C-12 and C-13, while compound 4 suffered a carbon bond break between the C-4 and C-5 to form a rare 4,5-seco-pseudoguaiane lactone. Compounds 1-3, 5, 13-16 and 25-27 exhibited anti-inflammatory activity by inhibiting NO production in LPS-induced RAW264.7 macrophages with IC50 values less than 40 μM, while compounds 1, 2, 5, 13, 14, 16, and 25-27 showed significant inhibitory activity comparable to that of dexamethasone. The anti-atopic dermatitis (AD) effects of compounds 5 and 16 were tested according to 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in KM mice, and the results revealed that the major products 5 and 16 improved the histological features of AD-like skin lesions and mast cell infiltration in mice. This study suggested that sesquiterpenoids in C. abrotanoides should play a key role in its anti-inflammatory use.

Chemoreactive 2,5-Diketopiperazines from a Penicillium sp., Structure Revision of Reported Analogues and Proposed Facile Transformation Pathways

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous cancer. Two new prenylated indole 2,5-diketopiperazine alkaloids, brevianamides E1 (1) and E2 (2), were isolated from a Penicillium fungus. Both compounds showed moderate cytotoxic activity against select MCC cell lines (i.e., MCC13, MKL-1, UISO, and WaGa) in the low micromolar range. The relative and absolute configurations of 1 and 2 were determined by combined approaches, including NOESY spectroscopy, DFT ECD and DP4 plus calculations, and Marfey's reaction. Literature research and the comparison of NMR and ECD data led to the structure revision of three previously reported natural analogues, notoamides K and P and asperversiamide L. The structurally unstable 1 and 2 underwent steady interconversion under neutral aqueous conditions. Investigation of the degradation of 2 in acidic methanol solutions led to the identification of a new methoxylated derivative (6) and two new ring-opened products (7 and 8) with the rearranged, elongated, 4-methylpent-3-ene side chain. The facile transformation of 2 to 7 and 8 was promoted by the intrinsic impurity (i.e., formaldehyde) of HPLC-grade methanol through the aza-Cope rearrangement.

Phenolic Constituents with Glucose Uptake and GLUT4 Translocation Bioactivities from the Fruits of Cordia dichotoma

From the fruits of Cordia dichotoma, 11 new phenolic compounds, dichotomins A-K, were isolated, together with 19 known compounds. Through the analysis of detailed NMR data and HRESIMS data, the planar structures of all compounds were confirmed. Using NMR calculations, the absolute configuration of dichotomins A-K was elucidated by comparing their observed and computed electronic circular dichroism (ECD) spectra. Dichotomin H (8) and dichotomin I (9) were determined as two pairs of enantiomers. The enantiomers of compounds 8 and 9 were separated using chiral-phase high-performance liquid chromatography (HPLC), and the stereostructure of each enantiomer was determined by similarly calculating the ECD. Compounds 3, 5, 7, 17, 18, 23-25, and 27-30 increased glucose uptake by 1.04- to 2.85-folds at concentrations of 30 μg/mL. Further studies revealed that compounds 3 and 5 had a moderate effect on glucose transporter 4 (GLUT4) translocation activity in L6 cells. At 30 μg/mL, compound 3 significantly enhanced AMPK phosphorylation and GLUT4 expression. As a whole, compound 3 has the potential to be a drug candidate for the treatment of type 2 diabetes mellitus (T2DM).

Bioactive Naphthoquinone and Phenazine Analogs from the Endophytic Streptomyces sp. PH9030 as α-Glucosidase Inhibitors

A talented endophytic Streptomyces sp. PH9030 is derived from the medicinal plant Kadsura coccinea (Lem.) A.C. Smith. The undescribed naphthoquinone naphthgeranine G (5) and seven previously identified compounds, 6-12, were obtained from Streptomyces sp. PH9030. The structure of 5 was identified by comprehensive examination of its HRESIMS, 1D NMR, 2D NMR and ECD data. The inhibitory activities of all the compounds toward α-glucosidase and their antibacterial properties were investigated. The α-glucosidase inhibitory activities of 5, 6, 7 and 9 were reported for the first time, with IC50 values ranging from 66.4 ± 6.7 to 185.9 ± 0.2 μM, as compared with acarbose (IC50 = 671.5 ± 0.2 μM). The molecular docking and molecular dynamics analysis of 5 with α-glucosidase further indicated that it may have a good binding ability with α-glucosidase. Both 9 and 12 exhibited moderate antibacterial activity against methicillin-resistant Staphylococcus aureus, with minimum inhibitory concentration (MIC) values of 16 μg/mL. These results indicate that 5, together with the naphthoquinone scaffold, has the potential to be further developed as a possible inhibitor of α-glucosidase.

A new pair of butylphthalide diastereomers from the roots of Angelica sinensis

A new pair of butylphthalide diastereomers, dangguinolide A (1) and dangguinolide B (2), together with two known butylphthalide were isolated from Angelica sinensis. Their structures were determined by extensive spectroscopic analyses, and the absolute configurations of 1 and 2 were assigned via NMR calculations and ECD calculations. Their anti-inflammatory activities have evaluated in vitro.

Chromomycins from soil-derived Streptomyces sp. inhibit the growth of human non-small cell lung cancer cells by targeting c-FLIP

Three chromomycin derivatives, chromomycins A3 (1, CA3), A5 (2, CA5), and monodeacetylchromomycin A3 (3, MDA-CA3), were identified from the soil-derived Streptomyces sp. CGMCC 26516. A reinvestigation of the structure of CA5 is reported, of which the absolute configuration was unambiguously determined for the first time to be identical with that of CA3 based on nuclear magnetic resonance (NMR) data analysis as well as NMR and electronic circular dichroism calculations. Compounds 1-3 showed potent cytotoxicity against the non-small-cell lung cancer (NSCLC) cells (A549, H460, H157-c-FLIP, and H157-LacZ) and down-regulated the protein expression of c-FLIP in A549 cells. The IC50 values of chromomycins in H157-c-FLIP were higher than that in H157-LacZ. Furthermore, si-c-FLIP promoted anti-proliferation effect of chromomycins in NSCLC cells. In nude mice xenograft model, 1 and 2 both showed more potent inhibition on the growth of H157-lacZ xenografts than that of H157-c-FLIP xenografts. These results verify that c-FLIP mediates the anticancer effects of chromomycins in NSCLC.

Harzianolides B-G: Undescribed Butenolides isolated from the fungus Trichoderma harzianum ZN-4

Five undescribed γ-butyrolactones harzianolides BF (1-5), one precursor harzianolide G (6) along with two known analogues, were isolated and identified from the EtOAc extract of the liquid fermentation of Trichoderma harzianum ZN-4, which was obtained from the sediment of Zhoushan coastal area. Notably, compound 1 featured an unusual carbon skeleton with methylene-bridged furan rings system. Their structures were determined by detailed interpretation of NMR and mass spectroscopic data, and the absolute configurations were unambiguously established based on ECD quantum chemical calculations. In bioassay, 1 and 7 showed inhibitory activity against Pestalotiopsis theae, with MIC values of 25 and 50 μg/mL, respectively.

Diorygmones A-B, two new guaiane-sesquiterpenes from the cultured lichen mycobiont of Diorygma sp

Diorygma sp. is a native crustose-lichen in Vietnam. A mycobiont of this lichen was isolated, then cultivated. The present study described the isolation and structural elucidation of two new guaiane-type sesquiterpenes, namely diorygmones A-B. Their absolute chemical structures were elucidated by extensive 1D and 2D NMR analysis, high-resolution mass spectroscopy, electronic circular dichroism (ECD), and comparisons with the literatures. Compounds 1 and 2 were evaluated for cytotoxic activity against HepG2 cell line.

Lycopodium alkaloids from Huperzia serrata and their cholinesterase inhibitory activities

Huperzia serrata, belonging to the Lycopodiaceae family, has been traditionally utilized for the management of treating rheumatic numbness, arthritic pain, dysmenorrhea, and contusions. This plant is a rich source of lycopodium alkaloids, some of which have demonstrated notable cholinesterase inhibitory activity. The objective of this study was to identify lycopodium alkaloids with cholinesterase inhibitory properties from H. serrata. The structures of these alkaloids were elucidated by HRESIMS, NMR (including a 1H-15N HMBC experiment), ECD methods and single-crystal X-ray diffraction. The inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were assessed using a modified Ellman's method. Consequently, sixteen lycopodium alkaloids (1-16), including ten previously undescribed ones named huperradines A-G and huperradines I-K (1-7 and 9-11), along with one previously undescribed naturally occurring compound, huperradine H (8), were isolated from H. serrata. Among these, compounds 7 and 1 exhibited potent and moderate AChE inhibition, with IC50 values of 0.876 ± 0.039 μM and 13.125 ± 0.521 μM, respectively. Our results suggest that huperradine G (7) may be a promising lead compound for the development of new AChE inhibitors for Alzheimer's disease.

Six new diterpenoids with anti-inflammatory and cytotoxic activity from Isodon serra

Diterpenoids occupy an important slot of the natural products diversity space with wide ranges of bioactivities and complex structures, providing potential applications for the development of therapeutics. In this study, we reported four new abietane-type diterpenoids viroxocin B-E (1-4), a new totarane-type diterpenoid viroxocin F (5), and a new sempervirane-type diterpenoid viroxocin G (6) along with four known compounds (7-10), isolated and identified from a widely used Traditional Chinese Medicine, Isodon serra (I. serra). Their structures were established by spectroscopic data analysis, experimental and calculated electronic circular dichroism (ECD) data, as well as X-ray diffraction analysis. Compounds 2, 5, 7, 8 and 10 exhibited promising anti-inflammatory activities in lipopolysaccharide (LPS)-induced RAW 267.4 cells, and their inhibition rates on NO production were more than 60% at 10 μM. Compound 7 showed cytotoxicity against human renal cell carcinoma 769P at 20 μM, the inhibition rate was 52.66%.

Two new oleanane triterpenes from Maytenus hookeri

Two new triterpenes mayteneri A (1), mayteneri B (2), and seven known compounds (3-9) were isolated from stems of Maytenus hookeri Loes. The chemical structures of compounds 1 and 2 were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds 3-9 were determined by comparison of their spectral with those reported. Compounds 4-7 showed significant inhibitory activity for NLRP3 inflammasome, with the IC50 values of 2.36-3.44 μM.

Phellintremulins A-C, antinociceptive sesquiterpenoids from the medicinal fungus Phellinus tremulae

Phellintremulin A (1), a rearranged sesquiterpenoid with an unprecedented bicyclic backbone, and two previously unreported illudane-type sesquiterpenoids, namely phellintremulin B (2) and phellintremulin C (3), together with two known analogues (±)‒4 and (±)‒5, were isolated from cultures of the medicinal fungus Phellinus tremulae. Their structures and absolute configurations were established by means of spectroscopic data and HRESIMS analyses, as well as ECD and NMR calculations. A plausible biogenesis for 1 was discussed. The electrophysiological experiments showed that phellintremulins (A‒C) can inhibit Nav current in DRG neuron cells at 10 μM, with percentage inhibitions of 23.2%, 49.3%, and 31.7%, respectively. The antinociceptive activities of phellintremulins (A‒C) were evaluated via the acetic acid-induced writhing test in mice at a dose of 3 mg/kg. They showed significant antinociceptive effects with percentages of inhibition of 43.8%, 54.4%, and 50.6%, respectively, and phellintremulin B and C expressed more potent analgesic effect than lidocaine.

Structurally diverse isoquinoline alkaloids from the barks of Alangium salviifolium (L. f.) Wangerin and their cytotoxicity

Eleven undescribed isoquinoline alkaloids (1-8, 14, 15, and 24), along with 19 analogues (9-13, 16-23, and 25-30) were isolated from the barks of Alangium salviifolium. The structures of the undescribed compounds were elucidated through the analysis of their HR-ESI-MS, 1D and 2D NMR, IR, UV, and X-ray diffraction. The absolute configuration of 8 was established via the ECD calculation. Notably, compounds 1/2 and 3/4 were two pairs of C-14 epimers. The isolated alkaloids were evaluated for their cytotoxicity against various cancer cell lines, including SGC-7901, HeLa, K562, A549, BEL-7402, HepG2, and B16, β-carboline-benzoquinolizidine (14-22) and cepheline-type (24-28) alkaloids exhibited remarkable cytotoxicity, with IC50 values ranging from 0.01 to 48.12 μM. Remarkably, compounds 17 and 21 demonstrated greater cytotoxicity than the positive control doxorubicin hydrochloride. Furthermore, a significant proportion of these bioactive alkaloids possess a C-1' epimer configuration. The exploration of their structure-activity relationship holds promise for directing future investigations into alkaloids derived from Alangium, potentially leading to novel insights and therapeutic advancements.

Albiflorenes A-L, polyoxygenated cyclohex(a/e)ne diterpene esters from Kaempferia albiflora

Twelve polyoxygenated cyclohex(a/e)ne diterpene esters, named albiflorenes A-L (1-12), were isolated from the whole plants of Kaempferia albiflora, known as "Prao Mang Mum." Their structures and relative stereochemistry were determined by extensive spectroscopic analysis. Furthermore, the comparison of experimental electronic circular dichroism (ECD) curves with the curves predicted by TDDFT was used to determine the absolute configurations. Albiflorenes contain polyoxygenated cyclohexane (or cyclohexene) derivatives, which are linked to either isopimarane or abietane diterpene acid units. The discovery marks the first occurrence of a conjugate between polyoxygenated cyclohexane (or cyclohexene) rings and diterpenoids. Among the isolates, albiflorene C specifically exhibited antibacterial activity against Bacillus cereus with MIC and MBC values of 3.13 and 6.25 μg/mL, respectively.

Dentifragilones A-B and Other Benzoic Acid Derivatives from the European Basidiomycete Dentipellis fragilis

A chemical and biological exploration of the European polypore Dentipellis fragilis afforded two previously undescribed natural products (1 and 2), together with three known derivatives (3-5). Chemical structures of the isolated compounds were confirmed through 1D/2D NMR spectroscopic analyses, mass spectrometry, and by comparison with the reported literature. The relative and absolute configurations of 1 were determined according to the ROESY spectrum and time-dependent density functional theory electronic circular dichroism (TDDFT-ECD), respectively. Furthermore, the absolute configuration of dentipellinol (3) was revisited and revealed to be of (R) configuration. All the isolated compounds were assessed for their cytotoxic and antimicrobial activities, with some being revealed to have weak to moderate antimicrobial activity, particularly against Gram-positive bacteria.

A polysubstituted cyclopentane and two glycerol esters from the engineered strain Streptomyces sp. S35-LAL1

Activation of silencing gene clusters is an important way to discover structurally novel compounds. In this study, three undescribed compounds were obtained from an engineered strain of Streptomyces sp. S35-LAL1. They include a polysubstituted cyclopentane with an unprecedented 10-carbon skeleton (1) and two glycerol esters (2 and 3). The structures of compounds 1-3 were elucidated through analysis of their spectroscopic data including 1D, 2D NMR, optical rotation, and electronic circular dichroism (ECD).

Diaporchalasin A, a new PDE4 inhibitory cytochalasin from Conus marmoreus-derived fungus Diaporthe sp. XMA007

A novel cytochalasin named diaporchalasin A (1) bearing a cinnamenyl and an epoxy-macrocycloketone, and a new benzenepropionic acid derivative (2), and two known compounds (3 and 4) were isolated from Conus marmoreus-derived fungus Diaporthe sp. XMA007. Their structures were elucidated through detailed spectroscopic analysis, and the absolute configuration of 1 was determined by conformational analysis and TDDFT-ECD calculation. Their activity evaluation on PDE4 inhibition and breast cancer cell cytotoxicity were conducted, and compound 1 showed moderate inhibition on PDE4.

Structurally diverse phthalides from fibrous roots of Ligusticum chuanxiong Hort. and their biological activities

Falonolide A (1) and B (2), two novel polyyne hybrid phthalides resulting from unprecedented carbon skeleton polymerized by Z-ligustilide and falcarindiol, along with six new related phthalides (3-8), were isolated from Ligusticum chuanxiong Hort. Their structures were elucidated by spectroscopic analysis, computer-assisted structure elucidation (CASE) analysis, DP4+ probability analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway for 1-8 was proposed, and the production mechanism of 2 was revealed by density functional theory (DFT) method. Compounds 4 and 6 exhibited significant vasodilatory activity with EC50 of 8.00 ± 0.86 and 6.92 ± 1.02 μM, respectively. Compound 4 also displayed significant inhibitory effect of NO production with EC50 value of 8.82 ± 0.30 μM. Based on the established compounds library, structure-activity relationship analysis of phthalides was explored to provide insights into the drug development of vasodilators and anti-flammatory.

Two Undescribed Germacrane-Type Sesquiterpenoids from Salvia cavaleriei var. simplicifolia Stib. and Their Anti-Alzheimer's Disease Activity

Two undescribed germacrane-type sesquiterpenoids, salcasins A (1) and B (2), together with three known compounds (3-5) were isolated and identified from the whole plant of Salvia cavaleriei var. simplicifolia Stib. The structures of the undescribed compounds were elucidated on the basis of spectroscopic methods, such as HR-ESI-MS, 1D and 2D NMR data. The relative configurations of 1 and 2 were established by analyzing their NOESY spectra as well as by 13C NMR calculations with DP4+ probability analyses. The absolute configurations of 1 and 2 were determined by comparing experimental and calculated ECD spectra. Furthermore, the in vivo anti-Alzheimer's disease activities of 1-5 were evaluated using Caenorhabditis elegans AD pathological model. Among all isolated compounds, salcasin A (1) significantly delayed AD-like symptoms of worm paralysis, which may be a potential anti-AD candidate agent.

Six unprecedented 2-(2-phenethyl)chromone dimers from agarwood of Aquilaria filaria

Six new dimeric 2-(2-phenylethyl)chromones (1-6) were successfully isolated from the ethanol extract of agarwood of Aquilaria filaria from Philippines under HPLC-MS guidance. Compounds 1-6 are all dimers formed by linking 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone and flindersia 2-(2-phenylethyl)chromone via a single ether bond, and the linkage site (C5-O-C8'') of compound 2 is extremely rare. A variety of spectroscopic methods were used to ascertain their structures, including extensive 1D and 2D NMR spectroscopic analysis, HRESIMS, and comparison with literature. The in vitro tyrosinase inhibitory and anti-inflammatory activities of each isolate were assessed. Among these compounds, compound 2 had a tyrosinase inhibition effect with an IC50 value of 27.71 ± 2.60 μM, and compound 4 exhibited moderate inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with an IC50 value of 35.40 ± 1.04 μM.

Harzianic acids and oxazolidinone from the endophytic fungus Ilyonectria sp. and their cytotoxicity activity

Four undescribed compounds including three harzianic acids (1, 3 and 4) and one oxazolidinone (2), along with three known ones (5-7) were isolated from the solid fermented product of endophytic fungus Ilyonectria sp., their structures were elucidated as 1-amino-harzianic acid (1), ilyonectria-oxazolidinone (2),10'-nor- isoharzianic acid (3), isohomoharzianic acid (4), harzianic acid (5), isoharzianic acid (6), homoharzianic acid (7) by means of detailed chemical evidences and spectroscopic data analysis. All the compounds were evaluated for cytotoxicity against SMMC-7721 human cancer cell lines by MTS assay. Among the seven tested compounds, 1-amino-harzianic acid (1) demonstrated well cytotoxic activity against SMMC-7721 with IC50 value of 26.84 μM. The results of molecular docking indicated that compound exhibited moderate anti-tumor activity may through binding to apoptosis related proteins.

Four lathyrane diterpenoids from the seeds of Euphorbia lathyris

Four new diterpenoids, including three secolathyrane diterpenoids (1-3) and one lathyrane diterpenoid (4), together with seven known diterpenoids, were obtained in the shelled seeds of Euphorbia lathyris. In particular, 1-3 possess a rare split ring structure, and currently only one compound with the same skeleton has been identified in E. lathyris. Compound 4 furnishes an unprecedented oxygen bridge structure. The structures were identified using various spectral techniques, including NMR, HR-ESI-MS, single-crystal X-ray diffraction and calculated electronic circular dichroism (ECD). The biosynthetic pathway of 1-4 was inferred. Furthermore, the cytotoxic activities of all compounds (1-11) were measured on three human tumor cells. New compounds 2 and 3 showed moderate cytotoxic activities against U937 cells with IC50 values of 22.18 and 25.41 μM, respectively.

Flavonoids From the Aerial Parts of Sophora tonkinensis and Their Potential Anti-Inflammatory Activities

Four undescribed prenylated flavonoids, sophoratones A-D (1-4), and 17 known flavonoids, were obtained from the aerial parts of Sophora tonkinensis. Their structures with absolute configurations were elucidated by detailed interpretation of NMR spectroscopy, mass spectrometry, and ECD calculations. Meanwhile, the ability of these compounds to inhibit the release of nitric oxide (NO) by a lipopolysaccharide induced mouse in RAW 264.7 cells was assayed. The results indicated that some compounds exhibited clear inhibitory effects, with IC50 ranging from 19.91±1.08 to 35.72±2.92 μM. These results suggest that prenylated flavonoids from the aerial parts of S. tonkinensis could potentially be used as a latent source of anti-inflammatory agents.

Bioactive solanidane steroidal alkaloids from Solanum lyratum

Six previously unreported solanidane steroidal alkaloids, namely lyrasolanosides A-F, were isolated from Solanum lyratum. In addition, five known steroidal alkaloids were also identified. The structures of these compounds were determined through the use of NMR, HRESIMS,UV, IR and ECD analysis. To assess their bioactivities, the cytotoxic effects of the six previously unreported compounds were evaluated on A549 cells. The results revealed that lyrasolanoside B (2) exhibited the highest potency among them. Lyrasolanoside B (2) exhibited significant inhibition of cell migration, invasion, and adhesion dramatically. Mechanistically, it was found to suppress the activity of JAK2/STAT3 signaling pathway by downregulating the expression of phosphorylated JAK2/STAT3 in an exosome-dependent manner. In addition, lyrasolanoside B (2) was found to significantly upregulate the expression of E-cadherin and downregulate the expression of N-cadherin and vimentin. These findings indicate that lyrasolanoside B (2) inhibits the metastasis of A549 cells by suppressing exosome-mediated EMT. These findings suggest that lyrasolanoside B (2) may inhibit the metastasis of lung cancer by regulating A549-derived exosomes.

Genome-Driven Discovery of Hygrocins in Streptomyces rapamycinicus

Ansamycins, represented by the antituberculosis drug rifamycin, are an important family of natural products. To obtain new ansamycins, Streptomyces rapamycinicus IMET 43975 harboring an ansamycin biosynthetic gene cluster was fermented in a 50 L scale, and subsequent purification work led to the isolation of five known and four new analogues, where hygrocin W (2) belongs to benzoquinonoid ansamycins, and the other three hygrocins, hygrocins X-Z (6-8), are new seco-hygrocins. The structures of ansamycins (1-8) were determined by the analysis of spectroscopic (1D/2D NMR and ECD) and MS spectrometric data. The Baeyer-Villiger enzyme which catalyzed the ester formation in the ansa-ring was confirmed through in vivo CRISPR base editing. The discovery of these compounds further enriches the structural diversity of ansamycins.

Three New Ionone Glycosides from Rhododendron capitatum Maxim

Six ionone glycosides (1-3 and 5-7), including three new ones, named capitsesqsides A-C (1-3), together with an eudesmane sesquiterpenoid glycoside (4) and three known triterpenoid saponins (8-10) were isolated from Rhododendron capitatum. The structures of these compounds were determined by extensive spectroscopic techniques (MS, UV, 1D-NMR, and 2D-NMR) and comparison with data reported in the literature. The absolute configurations were determined by comparison of the experimental and theoretically calculated ECD curves and LC-MS analyses after acid hydrolysis and derivatization. The anti-inflammatory activities of these compounds were evaluated in the LPS-induced RAW264.7 cells. Molecular docking demonstrated that 2 has a favorable affinity for NLRP3 and iNOS.

The Discovery of Acremochlorins O-R from an Acremonium sp. through Integrated Genomic and Molecular Networking

The fermentation of a soil-derived fungus Acremonium sp. led to the isolation of thirteen ascochlorin congeners through integrated genomic and Global Natural Product Social (GNPS) molecular networking. Among the isolated compounds, we identified two unusual bicyclic types, acremochlorins O (1) and P (2), as well as two linear types, acremochlorin Q (3) and R (4). Compounds 1 and 2 contain an unusual benzopyran moiety and are diastereoisomers of each other, the first reported for the ascochlorins. Additionally, we elucidated the structure of 5, a 4-chloro-5-methylbenzene-1,3-diol with a linear farnesyl side chain, and confirmed the presence of eight known ascochlorin analogs (6-13). The structures were determined by the detailed interpretation of 1D and 2D NMR spectroscopy, MS, and ECD calculations. Compounds 3 and 9 showed potent antibacterial activity against Staphylococcus aureus and Bacillus cereus, with MIC values ranging from 2 to 16 μg/mL.

New lignans from Phyllanthodendron dunnianum

A new lignan phyllanins A (1) and a lignan phyllanins B (2) for which the absolute configuration was determined for the first time, along with four known lignans (3-6) were isolated from the branch and leaf extracts of Phyllanthodendron dunnianum. Their planar structures were mainly determined by a combination of 1D and 2D NMR, HRESIMS spectral analyses, and the absolute configurations of the compounds 1 and 2 were established by DFT GIAO 13C NMR and electronic circular dichroism (ECD) calculations. In addition, all these six lignans were firstly tested for the antibacterial activities against MRSA, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. Among these compounds, 2 and 5 showed potential antibacterial activities against MRSA and S. aureus with MIC values of 4 and 8 µg/mL, respectively.

Structural variety and pharmacological potential of naphthylisoquinoline alkaloids

Naphthylisoquinoline alkaloids are a fascinating class of natural biaryl compounds. They show characteristic mono- and dimeric scaffolds, with chiral axes and stereogenic centers. Since the appearance of the last comprehensive overview on these secondary plant metabolites in this series in 1995, the number of discovered representatives has tremendously increased to more than 280 examples known today. Many novel-type compounds have meanwhile been discovered, among them naphthylisoquinoline-related follow-up products like e.g., the first seco-type (i.e., ring-opened) and ring-contracted analogues. As highlighted in this review, the knowledge on the broad structural chemodiversity of naphthylisoquinoline alkaloids has been decisively driven forward by extensive phytochemical studies on the metabolite pattern of Ancistrocladus abbreviatus from Coastal West Africa, which is a particularly "creative" plant. These investigations furnished a considerable number of more than 80-mostly new-natural products from this single species, with promising antiplasmodial activities and with pronounced cytotoxic effects against human leukemia, pancreatic, cervical, and breast cancer cells. Another unique feature of naphthylisoquinoline alkaloids is their unprecedented biosynthetic origin from polyketidic precursors and not, as usual for isoquinoline alkaloids, from aromatic amino acids-a striking example of biosynthetic convergence in nature. Furthermore, remarkable botanical results are presented on the natural producers of naphthylisoquinoline alkaloids, the paleotropical Dioncophyllaceae and Ancistrocladaceae lianas, including first investigations on the chemoecological role of these plant metabolites and their storage and accumulation in particular plant organs.

Bioactive Alkaloids from the Mangrove-Derived Fungus Nigrospora oryzae SYSU-MS0024

Chemical investigation of marine fungus Nigrospora oryzae SYSU-MS0024 cultured on solid-rice medium led to the isolation of three new alkaloids, including a pair of epimers, nigrosporines A (1) and B (2), and a pair of enantiomers, (+)-nigrosporine C (+)-3, and (-)-nigrosporine C (-)-3, together with eight known compounds (4-11). Their structures were elucidated based on extensive mass spectrometry (MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopic analyses and compared with data in the literature. The absolute configurations of compounds 1-3 were determined by a combination of electronic circular dichroism (ECD) calculations, Mosher's method, and X-ray single-crystal diffraction technique using Cu Kα radiation. In bioassays, compound 2 exhibited moderate inhibition on NO accumulation induced by lipopolysaccharide (LPS) on BV-2 cells in a dose-dependent manner at 20, 50, and 100 μmol/L and without cytotoxicity in a concentration of 100.0 μmol/L. Moreover, compound 2 also showed moderate acetylcholinesterase (AChE) inhibitory activities with IC50 values of 103.7 μmol/L. Compound 5 exhibited moderate antioxidant activity with EC50 values of 167.0 μmol/L.

Two aromatic acid derivatives and a xanthone from Hypericum hengshanense

Three previously undescribed compounds including two aromatic acid derivatives (1-2), and one xanthone (3), together with ten known compounds (4-13) were isolated from the aerial part of Hypericum hengshanense. The planar structures of three new compounds were established by 1 D and 2 D NMR and MS data. And the absolute configurations of compounds 1-2 were determined by the quantum chemical ECD calculations. Compounds 1-2 showed weak cytotoxicity against Hep-2 human cancer cell lines with IC50 values of 65.1 ± 2.7 and 78.0 ± 1.0 μg/mL, respectively.

Drimane-type sesquiterpenoids and their anti-inflammatory evaluation from Pyrrhoderma noxium HNNU0524

Chemical investigation of a culture broth from the marine-derived fungus Pyrrhoderma noxium HNNU0524 yielded two new compounds including a drimane-type sesquiterpenoid named pyrrnoxin A (1) and a benzoic acid derivative, pyrrnoxin B (5), together with three related known analogues (2-4). The chemical structures of 1 and 5 were determined by detailed analysis of spectroscopic data, single-crystal X-ray crystallography, quantum mechanics-based DP4+ and ECD calculations. Compounds 2 and 3 moderately inhibited NO production of lipopolysaccharide-induced microglia cells BV2 with IC50 values of 26.6 and 60.5 µM, respectively.

Globunoids A-D, undescribed bichalconoid and biflavanoids with α-glucosidase and α-amylase inhibitory activities from Knema globularia stems

A bichalconoid, globunoid A (1) and three biflavanones, globunoids B-D (2-4), previously undescribed, were isolated from the stems of Knema globularia, along with fourteen known analogues 5-18. The chemical structures of 1-4 were elucidated by the comprehensive spectroscopic analysis including UV, IR, HRESIMS, and NMR; the absolute configurations were determined based on their NOESY data, DP4+ statistical analysis, and ECD calculation. Up to now, compounds 2 and 3 represent the first 3,3″-linked biflavanone structures. Among the isolated compounds, 2, 3, and 2,3-dihydrocalodenin B (6) potently inhibited α-glucosidase and α-amylase activities, with IC50 values in the range 1.1-7.5 μM. Furthermore, the most active compound 6 was found to be a non-competitive inhibitor against these two enzymes.

Antiproliferative polycyclic polyprenylated acylphloroglucinols from Garcinia paucinervis

Bioassay-guided isolation of the stems of Garcinia paucinervis led to one new adamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), (-)-garpauvinin A (1), and four known analogues (2-5). The structure and absolute configuration of 1 was established via spectroscopic techniques and ECD method. All the isolates displayed moderate antiproliferative activity against HL-60, PC-3 and Caco-2 human cancer cell lines with IC50 values ranging from 0.81 to 19.92 μM, and exhibited low toxicity on WPMY-1 normal human cells, showing selectivity between normal and malignant prostate cells. The biosynthetic pathways of the isolated PPAPs were proposed.

Cytotoxicity sesquiterpenoids from the leaves of Datura stramonium L

Four new sesquiterpenoids, dstramonins A-D (1-4), and one new natural product (5), together with three known compounds (6-8), were isolated from the leaves of Datura stramonium L. The structures of new compounds were elucidated by extensive spectroscopic analysis and comparison with the literature. The cytotoxicity of isolates against LN229 cells was assessed and compounds 2-4, and 7 displayed cytotoxic activity with IC50 values ranging from 8.03 to 13.83 μM.

Terpenoids from Alpinia galanga and their acetylcholinesterase inhibitory activity

A new labdane diterpene (1), two new norsesquiterpenoids (2-3), as well as eight known terpenoids (4-11) were isolated from the seeds of Alpinia galanga (Zingiberaceae). Their structures and absolute configurations were elucidated by 1D, 2D NMR, MS, and comparison of their experimental and calculated electronic circular dichroism (ECD). The acetylcholinesterase (AChE) inhibitory activities of all the isolated compounds (1-11) were evaluated and the result showed that compounds 6 and 9 had inhibitory activity against AChE, with IC50 values at 295.70 and 183.91 μM, whereas other compounds did not show any inhibitory activity.

Antibacterial Polyketides from the Deep-Sea Cold-Seep-Derived Fungus Talaromyces sp. CS-258

Thirty-two fungal polyketide derivatives, including eleven new compounds, namely (3R,5'R)-5-hydroxytalaroflavone (1), talaroisochromenols A-C (3, 5, and 11), (8R,9R,10aR)-5-hydroxyaltenuene (13), (8R,9R,10aS)-5-hydroxyaltenuene (14), (8R,9S,10aR)-5-hydroxyaltenuene (15), nemanecins D and E (25 and 26), 2,5-dimethyl-8-iodochromone (27), and talarofurolactone A (29), together with one new naturally occurring but previously synthesized metabolite, 6-hydroxy-4-methoxycoumarin (28), were isolated and identified from the deep-sea cold-seep-derived fungus Talaromyces sp. CS-258. Among them, racemic ((±)-11) or epimeric (13-15, 25, and 26) mixtures were successfully separated by chiral or gradient elution HPLC. Meanwhile, compound 27 represents a rarely reported naturally occurring iodinated compound. Their planar structures as well as absolute configurations were determined by extensive analysis via NMR, MS, single-crystal X-ray diffraction, Mosher's method, and ECD or NMR calculation (with DP4+ probability analysis). Possible biosynthetic routes of some isolated compounds, which are related to chromone or isochromone biosynthetic pathways, were put forward. The biological analysis results revealed that compounds 7, 9, 10, 18-22, 24, 30, and 31 showed broad-spectrum antibacterial activities against several human and aquatic pathogens with MIC ranges of 0.5-64 μg/mL.