Lanicepines A and B, Sesquiterpenes with Amino Acid-Derived Substituents from the Flowering Aerial Parts of Saussurea laniceps.

Two new guaianolide sesquiterpenes, lanicepines A (1) and B (2), possessing unusual amino acid-derived substituents at C-13, were isolated from the flowering aerial parts of Saussurea laniceps, a traditional herbal medicine also known as "snow lotus". The structures of 1 and 2 were elucidated based on spectroscopic analysis including applications of the modified Mosher's method and Marfey's method as well as ECD calculations. Lanicepine A (1) contains a dihydropyridinone moiety with a carbamoyl and a hydroxymethyl group. This substituent was considered to consist of asparagine and a C4 unit. In contrast, lanicepine B (2) has a substituent that seems to be derived from l-proline and a C4 unit. Lanicepines A (1) and B (2) and two related known sesquiterpenes isolated from the same plant material, 11ß,13-dihydrodesacylcynaropicrin (3) and 11ß,13-dihydrodesacylcynaropicrin 8-O-ß-d-glucoside (4), demonstrated inhibitory activity against IL-1ß production from LPS-stimulated microglial cells.

Sesquiterpene lactones from Carpesium abrotanoides L. and their activity in inducing protective autophagy.

Fourteen sesquiterpene lactones were isolated from the whole plant of Carpesium abrotanoides L. Their structures were determined on the basis of comprehensive spectroscopic data analysis. All compounds were screened for their cytotoxic activity, and compound 6 showed the strongest activity (IC50 2.73 - 7.21 µM) against five human cancer cell lines, including A549, HepG2, HCT116, MDA-MB-231, and CNE2. Compound 6 was further investigated. Compound 6 effectively induced G2/M cell cycle arrest and ROS accumulation in a dose-dependent manner, which further led to apoptosis in cancer cells. Interestingly, compounds 1 and 6 could also activate protective autophagy, which was reported for the first time in sesquiterpene isolated from Carpesium abrotanoides. In addition, compounds 1 and 6 could induce lysosomal biogenesis by 173.2% and 163.7%, respectively. In sum, sesquiterpene lactones from Carpesium abrotanoides could induce apoptosis and protective autophagy in cancer cells, which provide a serial of compounds with potential clinical applications.

Ten new nortriterpenes from Euphorbia resinifera and their anti-tomato yellow leaf curl virus activities.

Ten new nortriterpenes, euphorbiumrins A-J (1-10), together with three known analogues (11-13) were isolated from the latex of Euphorbia resinifera. Their structures were established on the basis of extensive spectroscopic analyses (IR, UV, HRESIMS, 1D and 2D NMR). Their inhibitions on tomato yellow leaf curl virus (TYLCV) were evaluated and compound 5 exhibited significant anti-TYLCV activity with an inhibition rate of 71.7% at concentration of 40 µg/mL.

Diterpenes with potential treatment of vitiligo from the aerials parts of Euphorbia antiquorum L.

Six new diterpenes Euphonoids A-F including one ingenol (1), three lathyrane (2-5), one ent-abietane (6) and fifteen known derivatives (7-21) were isolated from the aerial parts of Euphorbia antiquorum L. Their structures were elucidated by physical data analysis. Compounds 1, 12, and 16 improve the melanogenesis in B16 cells in vitro.

Two New C21 Steroidal Glycosides from the Roots of Cynanchum paniculatum.

Two new C21 steroidal glycosides, paniculatumosides H and I, together with four known ones were isolated from the roots of Cynanchum paniculatum (Bge.) Kitag. Their structures were identified by spectroscopic methods including extensive 1D and 2D NMR techniques. All compounds were subjected to detect the anti-tobacco mosaic virus (TMV) activities and their cytotoxities against three human tumor cell lines (SMMC-7721, MDA-MB-231 and A549). The results showed that compounds 1 and 5 exhibited potent protective activities against TMV, while 2, 4 and 6 had moderate effects on the SMMC-7721 cancer cells viability.

Anti-TMV Effects of Amaryllidaceae Alkaloids Isolated from the Bulbs of Lycoris radiata and Lycoricidine Derivatives.

Fifteen known amaryllidaceae alkaloids were isolated from the bulbs of Lycoris radiata. Some of the compounds and lycoricidine derivatives had been screened for the activities against tobacco mosaic virus (TMV) by the conventional half-leaf method. Lycoricidine derivatives were also carried out the assay of effect on systemic infection of TMV by western-blot and RT-PCR analysis. The tested compounds showed moderate inactivation effect, whereas the lycoricidine derivatives showed good protective effect. The protective inhibitory activity of compounds L1 (N-methyl-2,3,4-trimethoxylycoricidine) (60.8%) and L3 (N-methyl-2-methoxy-3,4-acetonidelycoricidine) (62.0%) was almost similar to the positive control, Ningnanmycin (66.4%). RT-PCR and Western-blot analysis displayed that compounds L1, L3, L5 (N-allyl-2,3,4-triallyloxylycoricidine) exhibited antiviral activity, which was evidenced by reducing TMV-CP gene replication and TMV-CP protein expression. Additionally, defensive enzyme activities confirmed that compound L1 could increase the activity of PAL, POD, SOD to improve disease resistance of tobacco.

Cytotoxic indole alkaloids from Melodinus khasianus and Melodinus tenuicaudatus.

Four new indole alkaloids, melodinusines A-D (1, 2, 6, and 7), along with 26 known indole alkaloids, were isolated from Melodinus tenuicaudatus and Melodinus khasianus (Melodinus genus). Among them, 1 and 2 are aspidospermine-aspidospermine-type bisindole alkaloids while 7 is a novel melodinus-type alkaloid. Their structures were established on the basis of comprehensive spectroscopic data analysis and the structure of 7 was further confirmed by single-crystal X-ray diffraction analysis. Their cytotoxic activities against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7, and SW480 were also evaluated.

Identification of Ingol and Rhamnofolane Diterpenoids from Euphorbia resinifera and Their Abilities to Induce Lysosomal Biosynthesis.

The phytochemical study of Euphorbia resinifera afforded 18 structurally diverse diterpenoids, including 14 new ingol-type diterpenoids, euphorblins A-N (1-14), a new rhamnofolane diterpenoid, euphorblin O (15), and three known analogues (16-18). The structures of these compounds were deduced using 2D NMR spectroscopy and NOE experiments. The structure of compound 1 was confirmed by single-crystal X-ray crystallography. The abilities of the compounds to enhance lysosomal biosynthesis were evaluated through LysoTracker Red staining. Among the 10 active compounds, compounds 2, 4, and 18 showed remarkable immunofluorescence strength, and their LysoTracker staining intensities were 155.9%, 143.5%, and 140.7%, respectively, greater than that of the control. A series of lysosomal genes were also found to be upregulated by these compounds, which further confirms their ability to induce lysosome biosynthesis and suggests that these diterpenoids have potential as lead compounds for the development of drugs for the treatment of lysosome-related diseases.

Rigenolides D-H, norsecoiridoid and secoiridoids from Gentiana rigescens Franch.

Five new compounds, rigenolides D-H (1-5), were isolated from the aerial parts of Gentiana rigescens Franch. Their structures were assigned by detailed spectroscopic analyses and chemical conversions. Rigenolides D (1) and E (2) were elucidated to be a secoiridoid and a norsecoiridoid, respectively, possessing a dienone moiety in common. Rigenolides F-H (3-5) were assigned as acylated secoiridoid glucosides.

Two novel diterpenoid heterodimers, Bisebracteolasins A and B, from Euphorbia ebracteolata Hayata, and the cancer chemotherapeutic potential of Bisebracteolasin A.

Rare ent-abietane-rosane diterpenoid heterodimers, Bisebracteolasins A and B (1 and 2, respectively), were isolated from the roots of Euphorbia ebracteolata Hayata. Their structures and absolute configurations were elucidated from spectroscopic data and X-ray diffraction analysis. Compounds 1 and 2 exhibited moderate cytotoxic effects against five cancer cell lines. Compound 1 showed more effective antiproliferative activities against human tumour cells, HL-60 and SMMC-7721, with IC50 values of 2.61 and 4.08 µM, respectively, than 2. Both compounds 1 and 2 inhibit the colorectal cancer stem cell line P6C with IC50 values of 16.48 and 34.76 µM, respectively. Moreover, preliminary biological tests showed compound 1 exhibited inhibitory activity towards tumoursphere formation and migration of the P6C cell line. Overall, we identified two novel diterpenoid heterodimers, and Bisebracteolasin A exhibits therapeutic potential in impeding tumour growth and metastatic ability of cancer stem cells.

(±)-Perforison A, A Pair of New Chromone Enantiomers from Harrisonia perforata.

(+)-Perforison A and (-)-perforison A, a new pair of chromone enantiomers, along with four known compounds, were isolated from the leaves and stems of Harrisonia perforata. Their structures and absolute configurations were determined on the basis of extensive analysis of spectroscopic data and electronic circular dichroism (ECD) calculations. The cytotoxic activities in vitro of these compounds were evaluated, but none showed significant activity.

Cycloartane triterpenoid and its glucoside isolated from Cassia occidentalis.

In the present study, one new cycloartane triterpenoid, named cycloccidentalic acid C (1) and its glucoside, cycloccidentaliside VI (2) were isolated from the whole plant of Cassia occidentalis. Their structures were elucidated by a combinational analyses of 1D and 2D NMR data and HRMS. Compound 2 showed modest anti-HIV-1 activity with EC50 value of 1.44 µmol·L-1 and TI (Therapeutic Index) value of 15.59.

Four new tetracyclic alkaloids with cis-decahydroquinoline motif from Myrioneuron effusum.

Four new Myrioneuron alkaloids, mysumamides A-D (1-4), along with three known ones were isolated from the twigs and leaves of Myrioneuron effusum. All of these alkaloids possessed the tetracyclic skeleton and contained the decahydroquinoline (cis-DHQ) moiety. Their structures and relative configurations were elucidated on the basis of spectroscopic methods, especially 2D NMR techniques. The absolute configuration of 1 was determined by single-crystal X-ray diffraction. The cytotoxic activities of these compounds were also evaluated in vitro.

Antimicrobial Diterpenoids of Wedelia trilobata (L.) Hitchc.

Continued interest in the metabolites of Wedelia trilobata (L.) Hitchc, a notoriously invasive weed in South China, led to the isolation of twenty-six ent-kaurane diterpenoids, including seven new ones 1-7. Their structures and relative configuration were elucidated on the basis of extensive spectroscopic analysis, including 1D- and 2D-NMR experiments. The antimicrobial activities of all isolated diterpenoids were evaluated against a panel of bacteria and fungi.

Alkaloids with Different Carbon Units from Myrioneuron faberi.

Three new Myrioneuron alkaloids, myrifamines A-C (1-3), with unique skeletons were isolated from Myrioneuron faberi. The absolute configuration of 1 was confirmed by single-crystal X-ray diffraction analysis, and the stereochemistry of the other two alkaloids was determined using a combination of ROESY experiments and calculated and experimental electronic circular dichroism spectra. Myrifamine C (3) is the first example of a symmetric dimer among the Myrioneuron alkaloids. Known alkaloids myrionamide (4) and schoberine (5) were also isolated, and experimental NMR and X-ray diffraction data suggest their structural revision. Compound 2 showed significant inhibitory activity toward the hepatitis C virus in vitro, with a therapeutic index (CC50/EC50) greater than 108.7.

Bioactive Limonoid Constituents of Munronia henryi.

Fourteen new limonoids, munronins A-N (1-14), and eight known limonoids (15-22) were isolated from the whole plants of Munronia henryi. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry, and the structure of 8 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 represents the first limonoid found with a novel 7-oxabicyclo[2.2.1]heptane moiety produced by incorporating C-11 and C-14 via an oxygen atom. All compounds were evaluated for their anti-tobacco mosaic virus (TMV) activity and in vitro cytotoxicity against the human cancer HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines. Among them, compounds 2, 8, 9, 10, 11, 12, 18, and 20 showed significant anti-TMV activity, with IC50 values in the range 19.6-44.4 µg/mL. Compounds 1 and 18 exhibited cytotoxic effects for all five cancer cell lines, with IC50 values between 0.4 and 4.8 µM.

Chemical Constituents from the Stems of Manihot esculenta.

Two new compounds, maniesculentins A (1) and B (6), together with four known ones were isolated from the stems of Manihot esculenta Crantz. The structures of the new compounds were elucidated by extensive spectroscopic methods including NMR spectroscopy and mass spectrometry. The two new compounds (1, 6) were assayed for antibacterial activity against four tested bacteria lines.

Cyclohexane-fused octahydroquinolizine alkaloids from Myrioneuron faberi with activity against hepatitis C virus.

Investigation of the alkaloids from Myrioneuron faberi, a plant unique to China, gave four pairs of enantiomers (1-4). (±)-ß-Myrifabral A (1) and (±)-α-myrifabral A (2) formed an inseparable mixture of anomers (cluster A), as did (±)-ß-myrifabral B (3) and (±)-α-myrifabral B (4) (cluster B). Their structures were determined by X-ray diffraction and NMR analysis. Compounds 1-4 possessed novel cyclohexane-fused octahydroquinolizine skeletons and represent the first quinolizidine alkaloids from the genus Myrioneuron. The epimers of cluster A (1 and 2) were modified and separated. In vitro, clusters A and B and their derivatives inhibited replication of hepatitis C virus (HCV, IC50 0.9 to 4.7 µM) with cytotoxicity lower than that of telaprevir.

Antimicrobial Constituents of the Mature Carpels of Manglietiastrum sinicum.

Seven new compounds, including a eupodienone-type lignan (1), a dibenzocyclooctadiene-type lignan (2), three tetrahydrofuran-type lignans (3-5), and two 1-phenylbutyl benzoates (6, 7), together with six known compounds, were isolated from the mature carpels of Manglietiastrum sinicum. The structures of new compounds 1-7 were defined by spectroscopic techniques, and the absolute configuration of manglisin A (1) was determined by X-ray crystallography. Compounds 1-4 exhibited moderate antimicrobial activities (MIC values: 0.016-0.14 µM) against Staphylococcus aureus, MRSA 82(#), MRSA 92(#), MRSA 98(#), and MRSA 331(#). Compounds 2 and 3 showed weak cytotoxic activity against five human tumor cell lines.

Japodagricanones A and B, novel diterpenoids from Jatropha podagrica.

Two novel diterpenoids, japodagricanones A (1) and B (2), along with their biogenetically related diterpenoid 15-epi-4E-jatrogrossidentadion (3), were isolated from the leaves and twigs of Jatropha podagrica. Japodagricanones A (1) and B (2) are the first C-5-nor lathyrane-type diterpenoids. Their structures were established using spectroscopic data, including MS, NMR and ECD data. A plausible biosynthetic pathway for their generation was also proposed.