Eight new alkaloids, including three pairs of enantiomers (+)-(2′S,3′R)-clauselansine A (1a) and (−)-(2′R,3′S)-clauselansine A (1b); (+)-(2′S,3′R)-clauselansine B (2a) and (−)-(2′R,3′S)-clauselansine B (2b); (+)-(3S,4R,5S,6S)-clauselansine C (3a) and (−)-(3R,4S,5R,6R)-clauselansine C (3b), (+)-(1′R,2′R,6′R)-claulansine B (4a), and (+)-(1′R,2′R)-claulansine D (5a), together with twelve known alkaloids (4b, 5b, 6a, 6b, 7a, 7b and 8–13) were isolated from the stems of Clausena lansium. Their structural elucidation and stereochemistry determination were achieved by spectroscopic and chemical methods including 1D and 2D NMR experiments, especially the employment of electronic circular dichroism calculation spectra, Mosher's method, and Snatzke's method expressed by the induced circular dichroism spectrum. Compounds 1b, 2a, 3b, 5a, and 5b inhibited PC12 cell damage induced by Okadaic Acid, and increased cell viability from 70.5 ± 5.4% to 83.4 ± 4.1%, 91.2 ± 10.1%, 83.5 ± 7.8%, 89.7 ± 4.8%, 83.3 ± 5.9% at 10 μM, respectively.

Guajavadimer A (1), a dimeric sesquiterpene-based meroterpenoid which possessed an unprecedented two caryophyllenes, a benzylphlorogulcinol, and a flavonone-fused complicated stereochemical skeleton, was isolated from the leaves of Psidium guajava L. Its structure and absolute configuration were elucidated on the basis of spectroscopic data and X-ray crystallography. Guajavadimer A (1) showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced toxicity in HepG2 cells.

Eleven new monoterpenoids including three 1-methyl cantharimide-type derivatives (1–3), five 1,2-dimethyl cantharimide-type derivatives (4, 5, 7–9), and three 1-hydroxymethyl-2-methyl cantharimide-type derivatives (10–12), together with seven known cantharimides (6, 13–18), were isolated from Mylabis phalerata Palla. The planar structures and absolute configurations of compounds 1–14 were fully elucidated on the basis of spectroscopic analysis, ECD spectra, single-crystal X-ray diffraction analysis, and chemical methods. Compounds 6, 15, 16, and 18 were found to be potent inhibitors of HBV virus, with IC50 values of 62, 42, 58, and 19 μM.

•Four phenylpropanoid glucosides and five lignan glycosides were isolated from Lespedeza cuneata.•Their structures and absolute configurations were established from NMR and CD data.•Anti-ulcerative colitis activity was evaluated by dual luciferase report gene assay targeting xbp1.Four phenylpropanoid glucosides (1–4) and five lignan glycosides (5–9) were isolated from the aerial parts of Lespedeza cuneata, together with three known lignan glycosides (10–12). Their structures were elucidated on the basis of spectroscopic analyses, and the absolute configurations of compounds 5–9 were determined from the CD spectra. In addition, the compounds were tested for their ability to activate the transcription effect on xbp1 promoter. Compounds 4, 5, 7, 9, 10, and 12 could activate the transcription of xbp1 to varying degrees, with EC50 values ranging from 0.18 to 0.64 μM.Four phenylpropanoid glucosides (1–4) and five lignan glycosides (5–9) were isolated from the aerial parts of Lespedeza cuneata, together with three known lignan glycosides (10–12). Compounds 4, 5, 7, 9, 10, and 12 could activate the transcription of xbp1 to varying degrees, with EC50 values ranging from 0.18 to 0.64 μM.

Six new alkaloid glycosides, Clausenasides A–F (1–6), along with two new quinoline alkaloids, Clausenasides G–H (7–8), and ten known compounds (9–18) were obtained from the stems of C. lansium. The structures of the new compounds were elucidated on the basis of their spectroscopic analysis, and the absolute configurations of 1, 2, 3 and 7 were confirmed by Mosher's method, CD and ECD spectra, respectively. Compounds 4, 6, 9, 17, and 18 showed moderate inhibitory effects on LPS-induced NO production in murine microglial BV2 cells (IC50 values < 10 μM).

Tripterlides A–F (1–6), six new abietane diterpenoid derivatives, together with six known abietane diterpenoids (7–12) were obtained from the leaves of Tripterygium wilfordii. Tripterlides A–C (1–3) were novel 14(13 → 12),18(4 → 3)-diabeo-abietanoids possessing a 6/6/5 tricyclic ring system. These unusual structures, including their absolute configurations, were determined from UV, IR, HRESIMS, 1D and 2D-NMR data and through comparisons of their experimental and calculated electronic circular dichroism (ECD) spectra. A plausible biosynthetic pathway for 1–3 was proposed. Furthermore, in an in vitro bioassay, 5, 6, 8, and 10–12 showed significant cytotoxic effects against five human cell lines, and 6, 8, 10–12 also exhibited moderate inhibitory activities on hypoxia-inducible factor 1 (HIF-1), which is relevant to tumor development.

•Triptergulides A–D have not been previously reported as natural products.•Triptergulides A and B were novel rearranged abietane diterpenes.•Compounds 5–7 exhibited inhibitory effects on HIV-1 replication.•Five compounds demonstrated inhibitory effects on nitric oxide production.Two novel rearranged abietane diterpenes, triptergulide A (1) containing a fused 5/6/6/3/6/4 hexacyclic system and triptergulide B (2), possessing both 7/12 and 13/14 oxygen bridges, and two new 18(4→3)-abeo-abietanes, triptergulides C and D (3–4), together with three known diterpenoids (5–7) were isolated from the leaves of Tripterygium wilfordii. Among these compounds, compounds 5–7 exhibited inhibitory effects on HIV-1 replication with an IC50 range of 0.027–0.98 μM. Compounds 1, 2, 5, and 6 demonstrated inhibitory effects that were similar to the inhibitory effects of dexamethasone on nitric oxide production in LPS-induced macrophages at a concentration of 10 μM in an in vitro bioassay.

Twelve new A,D-seco-limonoids, clauemargines A–L (1–12), and three known analogues were isolated from the stems of Clausena emarginata. The absolute configurations of 1 and 5 were confirmed by X-ray crystallography and ECD spectroscopy, respectively. Compounds 1, 2, 8–10, and 13 showed moderate inhibitory effects on LPS-induced NO production (IC50 values < 10 μM).

Fifteen new lupane-type triterpenoids (1–15) and 10 known triterpenoids (16–25) were isolated from the stems of Euonymus carnosus. The structures of the new compounds were elucidated on the basis of spectroscopic analyses, and the absolute configuration of compound 1 was confirmed by X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. In addition, the compounds were tested for their cytotoxic activity against five human cancer cell lines and their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line. Compound 11 exhibited moderate cytotoxicity against several human cancer cell lines, and compounds 1, 2, 4, 5, 20, and 25 showed neuritis inhibitory activity against microglial inflammation factor, with IC50 values of 7.39, 7.48, 7.80, 3.48, 2.54, and 6.09 μM, respectively.

Twelve new dihydroagarofuran sesquiterpene polyol esters, triptersinines A–L (1–12), and eight known sesquiterpene pyridine alkaloids were isolated from the leaves of Tripterygium wilfordii. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, and NMR experiments (1H–1H COSY, NOESY, HSQC, and HMBC). Furthermore, in an in vitro bioassay, compounds 1, 9, 11, 13, 14, and 18 showed moderate inhibitory effects on nitric oxide production in LPS-induced macrophages at 5 μM; all compounds were inactive when tested against five human cancer cell lines (IC50 values >1 μM).

Eleven oleanane-type triterpenoid glycosides, named gordonsaponins A−K, were isolated from the stems of Gordonia kwangsiensis. Their structures were elucidated by spectroscopic and chemical methods. The cytotoxic activities of all eleven were evaluated against five human tumor cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780), with only one having activity against all tested cell lines, with IC50 values ranging from 0.1 to 2.41 μM.Graphical abstractEleven oleanane-type triterpenoid glycosides, named, gordonsaponins A−K (1–11), were isolated from the stems of Gordonia kwangsiensis. Their cytotoxic activities were tested.Highlights► Eleven oleanane-type triterpenoid glycosides were isolated from the stems of Gordonia kwangsiensis. ► All were evaluated for their cytotoxic activities. ► Only one showed activity against all tested cell lines, with IC50 values ranging from 0.1 to 2.41 μM.

Ten new carbazole alkaloids, claulansines A–J (1–10), and seven known analogues (11–17) were isolated from the stems of Clausena lansium. Their structures were established on the basis of extensive spectroscopic analyses, and their absolute configurations were determined by CD experiments and computational methods. Screening results indicated that compounds 1, 6, 8–10, 13, 14, and 17 showed selective neuroprotective effects at the concentration of 10 μM.

One new sesquiterpene lactone, 1α,8α,9α-trihydroxyeudesman-3(4),7(11)-dien-8β,12-olide (1) and two new phenylpropanoid-substituted catechin glycosides, glabraoside C (2) and glabraoside D (3) were isolated from the whole plant of Sarcandra glabra. Their structures were established by the analyses of spectral and chemical evidences.

Eight new oleanane-type triterpenoid glycosides, gordonosides I−P (1−8), and two new phenolic glycosides (9 and 10) were isolated from the stems of Gordonia chrysandra. Their structures were elucidated by spectroscopic and chemical methods. In an in vitro bioassay, compound 1 showed a strong inhibitory effect on nitric oxide production in LPS-activated macrophages with an IC50 value of 0.14 μM.

A new 3-(3,4-methylenedioxyphenyl)-propane-1,2-diol glycoside, named cinnamomdiol A (1), together with two known compounds, 3-(3,4-methylenedioxyphenyl)-propane-1,2-diol (2) and taxifolin (3), was isolated from the roots of Cinnamomum camphora. Their structures were determined on the basis of spectroscopic evidences. Compounds 2 and 3 were isolated from the title plant for the first time.

A new benzophenone glycoside, 2,6-dihydroxy-4-O-β-d-glucopyranosylbenzophenone (1), was isolated from the leaves of guajava L. Its structure was elucidated by spectral and chemical methods. 1 showed significant activities to secretion of NO in mouse peritoneal macrophages in 10 μmol/L.

Three novel sesquiterpenoid-based meroterpenoids of psidials A−C (1−3) have been isolated from the leaves of Psidium guajava L. Their complete structures were elucidated by spectral and chemical methods, and that of 1 was confirmed by single-crystal X-ray diffraction analysis. Psidial B (2) and C (3) represented the new skeleton of the 3,5-diformylbenzyl phloroglucinol-coupled sesquiterpenoid. A possible biosynthetic pathway for 2−3 was postulated. 2−3 showed activity to enzyme PTP1B in 10 μM.

Eight new oleanane triterpenoid glycosides, gordonosides A−H (1−8), were isolated from a 50% EtOH extract of the roots of Gordonia chrysandra. Their structures were determined by spectroscopic analysis, including 1D and 2D NMR and ESIMS, and by chemical methods. Among these substances, compounds 1, 3, 5, and 6 exhibited cytotoxic activity against several human cancer cell lines, with 3 being the most potent.

Bis-sesquiterpenes, henriols A (1), B (2), C (3), and D (4), and three diterpenes, henrilabdanes A (5), B (6), and C (7), together with two known bis-sesquiterpenes and three known labdane diterpenes, were isolated from the ethanol extract of the roots of Chloranthushenryi. Their structures and absolute configurations were elucidated by NMR spectroscopic, X-ray crystallographic and CD analyses. Compounds 1, 5, 6 and 7 showed moderate hepatoprotective activities with IC50 values of 0.19, 0.66, 0.09 and 0.18 μM, respectively. They were not studied further due to the weak effects noted. Compounds 3 and 8 exhibited cytotoxic activities against three types of cancer cell lines including the hepatoma (BEL-7402), human gastric carcinoma (BGC-823), and colon cancer (HCT-8).Four bis-sesquiterpenes and three diterpenes were isolated from roots of Chloranthus henryi. Compounds 1, 5, 6 and 7 showed moderate hepatoprotective activities against d-galactosamine-induced toxicity in WB-F344 rat hepatic epithelial stem-like cells with IC50 values of 0.19, 0.66, 0.09 and 0.18 μM, respectively. Moreover, compounds 3 and 5 showed cytotoxic activities against BEL-7402, HCT-8, and BGC-823 cells.

Two new phenylpropanoid glycosides named cuneataside E (1) and cuneataside F (2), were isolated from the aerial parts of Lespedeza cuneata (Dum. Cours.) G. Don, whose structures were E and Z isomer, respectively. Their structures were elucidated on the basis of comprehensive spectroscopic analysis (UV, IR, HR-ESI-MS, 1D and 2D NMR). In in vitro bioassays at 10 μmol/L, compound 1 showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced toxicity in HeG2 cells.Two new phenylpropanoid glycosides, cuneataside E (1) and cuneataside F (2), were isolated from the aerial parts of Lespedeza cuneate (Dum. Cours.) G. Don, as E and Z isomer, respectively. At the concentration of 10 μmol/L, compound 1 showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced toxicity in HepG2 cells.Download full-size image

•Seven isopimarane diterpenes and one abietane diterpene together with six known sesquiterpenes were isolated.•The absolute configuration of 1 was determined by single-crystal X-ray crystallographic analysis.•Inhibitory ability against LPS-induced nitric oxide production and cytotoxicity against A549 cell line growth.Seven isopimarane diterpenes and one abietane diterpene, together with six known sesquiterpene derivatives, were isolated from the stems of Euonymus oblongifolius. Their structures were elucidated on the basis of spectroscopic analyses, and the absolute configuration of euonymusisopimaric acid A was confirmed by single-crystal X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. All of the isolated compounds were evaluated for their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line, and for their cytotoxic activity against five human cancer cell lines. Euonymusisopimaric acids A, E and F inhibited LPS-induced nitric oxide production in the murine microglia BV2 cell line, with IC50 values of 2.4, 4.8, and 1.6 μM, respectively. Euonymusisopimaric acid B exhibited moderate cytotoxicity against A549 cell line growth, with an IC50 value of 2.6 μM.Seven isopimarane diterpenes (1–7) and one abietane diterpene (8) were isolated from stems of Euonymus oblongifolius.

•Six new pentacyclic triterpenes (1–6) were isolated from Euonymus carnosus.•Compounds 1–5 are among the relatively few pentacyclic triterpenes that incorporate a 3α-hydroxy (3α-acetoxy) group.•The inhibitory on LPS-induced NO production in microglia BV2 cells of compounds 1–8 were evaluated.Three new lupane-type triterpenoids (1–3), three new oleane-type triterpenoids (4–6), as well as two known compounds (7–8) were isolated from Euonymus carnosus. The structures of the compounds were elucidated on the basis of spectroscopic data analyses, including UV, IR, MS, and NMR experiments. The inhibitory on LPS-induced NO production in microglia BV2 cells of compounds 1–8 were also evaluated. Compounds 1 and 2 showed moderate abilities to inhibit NO production, with IC50 values of 5.99 and 8.47 μM, respectively.Three new lupane-type triterpenoids (1–3) and three new oleane-type triterpenoids (4–6) were isolated from the stems of Euonymus carnosus, together with two known compounds (7–8). In addition, compounds 1–5 are among the relatively few naturally occurring pentacyclic triterpenes that incorporate a 3α-hydroxy or 3α-acetoxy group. Compounds 1 and 2 showed moderate abilities to inhibit NO production, with IC50 values of 5.99 and 8.47 μM, respectively.Download high-res image (122KB)Download full-size image