Three New Cassane‐Type Diterpenes from Caesalpinia minax

Three new cassane‐type diterpenes, 14‐dehydroxy‐12,16‐dihydrocaesaldekarin L ( 1 ), 1‐deacetyl‐12‐ethoxyneocaesalpin N ( 2 ), and 1‐deacetylneocaesalpin N ( 3 ), together with two known cassane‐type diterpenes, neocaesalpin A and neocaesalpin L, were isolated from the EtOH extract of the twigs and leaves of Caesalpinia minax. Their structures were elucidated by spectroscopic methods, as well as by comparison of their spectral data with those of related compounds.     

Cassane‐Type Diterpenoids from the Seeds of Caesalpinia magnifoliolata

Two novel cassane‐type diterpenes, named magnicaesalpin ( 1 ) and neocaesalpin O ( 2 ), together with three known compounds, caesalmin D ( 3 ), caesalmin E ( 4 ), and neocaesalpin L ( 5 ), were isolated from the MeOH extract of seeds of Caesalpinia magnifoliolata Metc . Their structures were determined by spectroscopic methods, (1D‐ and 2D‐NMR, HR‐EI‐MS) and X‐ray analysis, as well as by comparison of their spectral data with those of related compounds.     

Cassane‐Type Diterpenes from the Seeds of Caesalpinia crista

A new dimer 1 and two new cassane‐type diterpenes 2 and 3 , designated taepeenin J–L, were isolated from the seeds of Caesalpinia crista L. Compound 1 possesses a dimeric vouacapane skeleton. Their structures were elucidated on the basis of spectroscopic analysis.     

Structure Revision of Caesalpinistas A and B and Isolation of a New Furanoditerpenoid from the Cotyledons of Caesalpinia decapetala var. japonica

A known cassane‐type furanoditerpenoid, caesalpinista B ( 1 ), and a new diterpenoid, deoxycaesaljaponin A ( 2 ), were isolated from the cotyledons of Caesalpinia decapetala var. japonica. The previously reported configurational assignments of 1 and the related diterpenoid caesalpinista A ( 3 ) were revised on the basis of X‐ray crystallography and chemical conversion. The structure of 2 was elucidated by spectroscopic data and chemical conversion into 3 .     

The isolation and structure elucidation of new cassane diterpene-acids from Caesalpinia crista L. (Fabaceae), and review on the nomenclature of some Caesalpinia species

New cassane diterpene-acids, neocaesalpins H and I, were isolated from the leaves of Caesalpinia crista (Fabaceae), and their structures were deduced on the basis of the spectroscopic and chemical basis. These compounds were characterized as having an alpha,beta-butenolide hemiacetal ring that is rare in nature. The lacking of 5-hydroxy group also distinguished neocaesalpins H and I from cassane diterpenes (caesalpins) occurring in other Caesalpinia species from the phytochemical viewpoint. The nomenclature of three Caesalpinia species was also reviewed, and it was found that some species belonging to the genus Caesalpinia are improperly named and should be changed to valid names.     

Caesaljaponins A and B: New Cassane‐Type Furanoditerpenoids from the Seeds of Caesalpinia decapetala var. japonica

Two new cassane‐type furanoditerpenoids, designated caesaljaponin A and caesaljaponin B ( 1 and 2 , resp.), were isolated from seeds of Caesalpinia decapetala var. japonica. The structures were elucidated by spectroscopic data, and the absolute configuration of 1 was determined by X‐ray crystallographic analysis using the anomalous scattering of CuK_α radiation.     

Antioxidative Cassane Diterpenoids from the Seeds of Caesalpinia minax

Five new cassane diterpenoids, caesalmins I–M ( 1 – 5 ), and 23 known analogs were isolated from the seeds of Caesalpinia minax. Their structures were elucidated by spectroscopic methods and comparison with reported data. The antioxidant properties of 1 – 28 were determined by the method of oxygen radical absorbance capacity of fluorescein (ORAC‐FL), and 14 compounds exhibited good antioxidant activities with ORAC‐FL values of 2.24–4.89 Trolox equivalents. The structure? activity relationship of the active compounds was also discussed.     

Chemical studies on the Philippine crude drug calumbibit (seeds of Caesalpinia bonduc): the isolation of new cassane diterpenes fused with alpha,beta-butenolide

New cassane diterpenes named neocaesalpins C and D were isolated from the Philippine crude drug calumbibit botanically originating from the seeds of Caesalpinia bonduc (Fabaceae), and their structures were elucidated on the basis of the spectroscopic evidence. These compounds are characterized by the presence of the alpha,beta-butenolide moiety. Although a number of cassane furanoditerpenes have been known to occur in the same plant species, such constituents could not be isolated from the crude drug of Philippine origin in this study. It is presumed that the chemical difference resulted from chemical differentiation of the species.     

Three new cassane diterpenes from the seeds of Caesalpinia minax Hance

Four fractions were prepared from the crude extract of Caesalpinia minax Hance and the inhibitory activity of nitric oxide (NO) production release of RAW 264.7 cells stimulated by lipopolysaccharide (LPS) was evaluated. The ethyl acetate (EtOAc) fraction showed obvious inhibitory effect. Bioassay-guided fractionation led to the isolation of three new cassane diterpenes, caesalmin X (1), caesalmin Y (2) and caesalmin Z (3), together with 19 known cassane diterpenoids (4–22). Their structures were mainly characterised on the basis of extensive spectroscopic analyses and comparison with reported data. Moreover, three compounds (20–22) which possessed furanditerpenoid 7,17-lactone structures, displayed moderate activities, with IC₅₀ value of 29.85, 27.38 and 25.40 μM, respectively.     

Simultaneous identification and analysis of cassane diterpenoids in Caesalpinia minax Hance by high‐performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

Cassane diterpenoids were successfully and simultaneously identified in Caesalpinia minax Hance by high‐performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry. A total of 59 peaks were detected, and among them 51 compounds, including 41 furanocassane diterpenoids, 10 furanolactone cassane diterpenoids were simultaneously identified and characterized on the basis of the protonated molecule, retention behavior, and fragments in MS². Ten compounds, including seven novel compounds, were identified or tentatively identified for the first time in C. minax. In a positive ion mode, the fragmentation pathways of cassane diterpenoids were also analyzed for the first time. The relative amounts of the five main diterpenoids (caesalpinin L, caesalpinin F₂, bondcellpin C, caesalpinin E, and ξ‐caesalmin) were simultaneously quantified by high‐performance liquid chromatography. Results showed that the newly discovered and known components of C. minax can be used to determine the material basis of bioactivity; this method can also be applied to analyze cassane diterpenoids in herbal medicines from the genus Caesalpinia belonging to the family Fabaceae.     

Two new cassane diterpene lactams from the fruits of Caesalpinia mimosoides Lam

Two new cassane ditepenoid lactams, caesmimotam A (1) and B (2), along with eight known compounds (3–10) were isolated from the fruits of Caesalpinia mimosoides Lam. Their structures were identified by 1D and 2D NMR spectral data. Compounds 1 and 2 were evaluated for their cytotoxicity on HL-60, SMMC-7721, A-549, MCF-7 and SW-480 human cancer cell lines, but they were inactive.     

New Antifungal `Quinone Methide' Diterpenes from Bobgunnia madagascariensis and Study of Their Interconversion by LC/NMR

Two new `quinone methide' diterpenes with a cassane skeleton were isolated from the root bark of Bobgunnia madagascariensis (Desv. ) J. H. Kirkbr. & Wiersema (Leguminosae). The two compounds occurred as a diastereoisomer mixture 1 / 2 . Their structure was established as (4R,6aS,10aS)‐ and (4S,6aS,10aS)‐ 1,4,6a,7,8,9,10,10a‐octahydro‐4,11‐dihydroxy‐7,7,10a‐trimethyl‐2H‐phenanthro[1,2‐c]pyran‐6,12‐dione by spectroscopic methods and by comparison with the data obtained for another `quinone methide' diterpene isolated previously from the same plant and identified by single‐crystal X‐ray analysis. ¹H‐ and ¹³C‐NMR signals were assigned by extensive in‐mixture 2D correlation experiments, and ¹H‐NMR spectra of the separated diastereoisomers 1 and 2 were recorded by on‐flow LC/NMR. The interconversion of 1 and 2 was followed by repeated stop‐flow LC/NMR experiments over a two‐hour period. Compounds 1 and 2 showed moderate antifungal properties towards human pathogenic fungi, in particular the yeast Candida albicans.     

Pharmacokinetic and tissue distribution studies of cassane diterpenoids,in rats through an ultra‐high‐performance liquid chromatography–Q exactive hybrid quadrupole–Orbitrap high‐resolution accurate mass spectrometry

Cassane diterpenoids (CA) are considered as the main active constituents of medicinal plants belonging to the Caesalpinia genus. Three cassane derivatives, bonducellpin G (BG), 7‐O‐acetyl‐bonducellpin C (7‐O‐AC) and caesalmin E (CE), isolated from Caesalpinia minax Hance seeds, showed strong anti‐inflammatory activity. In this paper, pharmacokinetics (BG, 7‐O‐AC, CE) and tissue distribution (7‐O‐AC, CE) properties were studied for the first time using a reliable, sensitive and rapid UHPLC–Q‐Orbitrap HR‐MS to develop new anti‐inflammatory agents. A novel quantitative method with full scan in positive ion mode was used to determine the contents of compounds. They were separated using acetonitrile–water (0.1% formic acid) as gradient mobile phase. The calibration curve displayed good linearity and the lower limit of quantitation was 0.005–0.02 μg/mL for all analytes. Meanwhile, the absorption, distribution, metabolism, excretion (ADME) property was predicted using PreADMET web. The pharmacokinetic parameters indicated that they were absorbed quickly, eliminated rapidly together with high blood concentration. The results of tissue distribution demonstrated that CE was distributed rapidly and widely among tissues, and stomach was the main tissue site of CE and 7‐O‐AC, followed by small intestine/liver. This study indicates that the structures and dosages of active CA should be modified to help improve the absorption rate and residence time, and the findings are helpful for the pharmaceutical design of CA derivatives.     

Novel norcassane-type diterpene from the seed kernels of Caesalpinia crista

Three novel norcassane-type diterpenes were isolated from a CH₂Cl₂ extract of the seed kernels of Caesalpinia crista together with four known cassane-type diterpenes. All the new compounds represent unprecedented carbon framework. Norcaesalpinin A (1) and B (2) had 17-norcassane skeleton, while norcaesalpinin C (3) had 16-norcassane skeleton. Their structures were elucidated on the basis of spectral analysis.     

Two New Abietane Diterpenoids from the Roots of Tripterygium wilfordii Hook. f.

Two new abietane‐type diterpenoids, named triptobenzene R ( 1 ) and triptobenzene S ( 2 ), together with three known abietane‐type diterpenoids, triptophenolide ( 3 ), triptonodiol ( 4 ), and triptonoterpene methyl ether ( 5 ), were isolated from the roots of Tripterygium wilfordii Hook . f. Their structures and relative configurations were established by detailed spectral studies, including 1D‐ and 2D‐NMR (HSQC, HMBC, and NOESY), and HR‐ESI‐TOF‐MS, and by comparison with published data. Their absolute configurations were assigned by the CD technique, applied for the first time to abietane diterpenes from Tripterygium wilfordii. Compound 2 is the first abietane‐type norditerpenoid isolated from the genus Tripterygium.     

New diterpenoids from stems and roots of Caesalpinia crista

Nine new cassane-type diterpenes, named taepeenin A-I, and two new norcassane-type diterpenes, named nortaepeenin A-B, were isolated from the stems and roots of Caesalpinia crista along with three known diterpenes: vinhaticoic acid, methyl vinhaticoate and ent-11β-hydroxy-rosa-5,15-diene. Their structures were elucidated on the basis of spectroscopic analysis. In addition, the structure of taepeenin A was confirmed by X-ray diffraction analysis.     

ent‐Kaurane Diterpenes and Further Constituents from Wedelia trilobata

Two new ent‐kaurane diterpenes, wedelidins A ( 8 ) and B ( 9 ), together with eighteen other constituents, including the sesquiterpenoids 1 and 2 , ent‐kaurane diterpenes 3 – 7 , triterpenoids 10 and 11 , steroids 12 – 14 , and flavonoids 15 – 17 as well as benzene derivatives 18 – 20 , were isolated from the aerial parts of Wedelia trilobata. The structures of wedelidins A ( 8 ) and B ( 9 ) were elucidated by extensive spectroscopic analyses (including UV, IR, NMR, and MS). Furthermore, the structures of compounds 2 and 3 were confirmed by X‐ray single‐crystal diffraction analyses.     

Constituents of Caesalpinia crista from Indonesia

Ten new furanocassane-type diterpenes named, caesalpinins H-P (1-9) and norcaesalpinin F (10), were isolated from the CH(2)Cl(2) extract of the seed kernels of Caesalpinia crista, together with 13 known diterpenes. Their structures were determined based on the spectroscopic analysis. Among the isolated compounds, caesalpinin N (7) represents the first example of furanocassane-type diterpene possessing an aldehyde group at C-14.     

New cassane butenolide hemiketal diterpenes from the marine creeper Caesalpinia bonduc and their antiproliferative activity

Two new cassane butenolides, caesalpinolide A (1) and B (2), epimeric at the hemiketal position were isolated from the marine creeper Caesalpinia bonduc. The structures were elucidated by the analysis of spectroscopic data and relative stereochemistry was assigned on the basis of ROESY correlations. Compounds 1 and 2 were found to inhibit MCF-7 breast cancer cell lines with IC₅₀ values of (μM) 12.8 and 6.1, respectively, along with the inhibition of endometrial and cervical cancer cell lines.     

Terpenes and Polybromoindoles from the Marine Red Alga Laurencia decumbens (Rhodomelaceae)

Two new brominated diterpenes, namely, laurendecumtriol ( 1 ) and 11‐O‐deacetylpinnaterpene C ( 2 ), one new polybromoindole, 2,3,4,6‐tetrabromo‐1‐methyl‐1H‐indole ( 7 ), and six known natural products were isolated and identified from the marine red alga Laurencia decumbens. Their structures were elucidated on the basis of detailed spectroscopic and mass‐spectrometric analysis as well as by comparison with literature data. Based on 2D‐NMR experiments, the previously reported NMR data for pinnaterpene C ( 3 ) were reassigned.