Kadsufolins A – D and Related Cytotoxic Lignans from Kadsura oblongifolia

Kadsufolins A–D ( 1 – 4 , resp.), four new dibenzocyclooctane‐type lignans, were isolated from the roots and stems of Kadsura oblongifolia, together with eleven known lignans. Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR techniques. The compounds were also evaluated for cytotoxic activity against human tumor cell lines A549 (lung carcinoma), DU145 (prostate carcinoma), KB (epidermoid carcinoma of the nasopharynx), and HCT‐8 (ileocecal carcinoma). Kadsufolin A ( 1 ), kadsufolin D ( 4 ), angeloylbinankadsurin A, and heteroclitin B were found to show cytotoxic activities against A549, DU145, KB and HCT‐8 with GI₅₀ values of 5.1–20.0 μg/ml.     

Structural determination of aspericins A?C,new furan and pyran derivates from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61, by 1D and 2D NMR spectroscopy

Three new furan and pyran derivatives named aspericins A? C (1–3), as well as a known asperic acid (4), have been isolated from the marine‐derived fungus Rhizopus sp. 2‐PDA‐61. The complete ¹H and ¹³C NMR assignments for the new compounds were carried out using ¹H, ¹³C, DEPT, COSY, HMQC, HMBC, and NOESY NMR experiments. Compounds 1–3 were evaluated for their cytotoxic activities on P388, A549, HL‐60, and BEL‐7420 cell lines by the MTT and SRB methods. Copyright © 2009 John Wiley & Sons, Ltd.     

Seven New Lignan Esters from Kadsura philippinensis

Five new oxygenated lignans with a dibenzocyclooctadiene skeleton, kadsuphilols P–T ( 1 – 5 ), and two new C₁₉ homolignans, kadsuphilols U and V ( 6 and 7 ), were isolated by chromatographic fractionation of an AcOEt extract of the stems of Kadsura philippinensis. The structures of the isolated metabolites were elucidated through extensive spectroscopic analysis including HR‐ESI‐MS and 2D‐NMR (HMQC, COSY, and HMBC). The configuration at the chiral centers and at the biphenyl moiety were determined by interpretation of NOESY and CD data, respectively.     

1H and 13C NMR assignments of eight nitrogen containing compounds from Nocardia alba sp.nov (YIM 30243T)

An unprecedented new natural product named nocarsin A (1), 5H‐4a,6,7a‐triazacyclopenta[cd]indene‐5,7(6H)‐dione (1), together with seven known compounds lumichrome (2), cyclo (L ‐Leu‐L ‐Tyr) (3), cyclo (L ‐Ala‐L ‐Ile) (4), cyclo (L ‐Ala‐L ‐Leu) (5), cyclo (L ‐Val‐L ‐Ala) (6), 5‐methyluracil (7) and uracil (8), was isolated from Nocardia alba sp.nov (YIM 30243^T), which was isolated from a soil sample collected from Yunnan Province, P. R. China. NMR techniques including COSY, HSQC, ROESY, and HMBC were used to elucidate the structures of these compounds. We report the unambiguous assignments of the ¹H and ¹³C NMR spectra of the new compound nocarsin A (1). Copyright © 2009 John Wiley & Sons, Ltd.     

Structure determination of Aervins A‐D,new coumaronochromone analogues from Aerva persica,by 1D and 2D NMR spectroscopy

Aervins A‐D (1‐4), four new coumaronochromone analogues have been isolated from the CHCl₃‐soluble fraction of the MeOH extract of the whole plant of Aerva persica. Their structures were assigned based on ¹H NMR, ¹³C NMR spectra, DEPT, and by 2DNMR experiments. Copyright © 2009 John Wiley & Sons, Ltd.     

NMR and structure review of some natural furoclerodanes

The structures of some natural occurring furoclerodanes isolated from Croton cajucara were re‐examined using a more powerful NMR instrument (600 MHz for ¹H), 2D NMR experiments, AM1 calculations and ¹H spectrum simulations. This study led to new signal assignments and allowed us to establish the correct structure of the compound named sacacarin, which corresponding to its 20‐oxo‐isomer, is thus renamed iso‐sacacarin. Copyright © 2003 John Wiley & Sons, Ltd.     

New Oxygenated Lignans from Kadsura philippinensis

Seven new oxygenated lignans, kadsuphilins G–M ( 1 – 7 , resp.), were isolated by chromatographic fractionation of an AcOEt extract of the aerial part of Kadsura philippinensis including four compounds with a dibenzocyclooctadiene skeleton, two with a bicyclooctane ring system, and one of 1,4‐biphenyldimethylbutane type. The structures of the isolated compounds were elucidated through extensive spectroscopic analyses, particularly 2D‐NMR experiments (HMQC, HMBC, and NOESY). The configuration of the chiral centers and the biphenyl moiety were determined by NOESY as well as CD spectroscopy, respectively.     

Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.     

Complete assignments of 1H and 13C NMR data for seven arylnaphthalide lignans from Justicia procumbens

Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.     

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.     

Complete assignments of 1H and 13C NMR data for two new sesquiterpenes from Cyperus rotundus L.

Two new sesquiterpenes, epi‐guaidiol A (1) and sugebiol (3), together with four known sesquiterpenes, guaidiol A(2), sugetriol triacetate (4), cyperenoic acid (5), and cyperotundone (6) were isolated from the rhizomes of Cyperus rotundus L. Their structures were identified by MS and NMR experiments, and the complete assignments of ¹H and ¹³C NMR data for two new sesquiterpenes were obtained by the aid of two‐dimensional (2D) NMR techniques, including HSQC, HMBC, ¹H‐¹HCOSY and nuclear overhauser enhancement spectroscopy(NOESY). Copyright © 2009 John Wiley & Sons, Ltd.     

Four New Dibenzocyclooctene Lignans from Kadsura renchangiana

Four new dibenzocyclooctene‐type lignans, named renchangianins A–D ( 1 – 4 ), were isolated from the stems of Kadsura renchangiana. Their structures and configurations were elucidated by spectroscopic methods, including 2D‐NMR techniques. Renchangianin D ( 4 ) possesses a spiro[dibenzocyclooctene‐6,2′‐oxirane] parent structure previously unknown in plants of the Schisandraceae family.     

Chemical constituents isolated from stems of Schisandra chinensis and their antifeedant activity against Tribolium castaneum

Abstract

One new sesquiterpene (α-iso-cubebenol acetate, 8), together with 9 known compounds (1-7, 9, 10) were isolated from the stems of Schisandra chinensis (Turcz.) Baill. by repeated silica gel column chromatography. Based on the results of MS, NMR spectra and comparing with literature data, the six dibenzocyclooctadiene lignans were identified as schizandrin A to C (1-3), schizandrin (4), schisantherin A (5) and gomisin J (6), the two sesquiterpenes were identified as α-iso-cubebenol (7) and α-iso-cubebenol acetate (8), while the two triterpenic acids were identified as ganwuweizic acid (9) and kadsuric acid (10). The antifeedant activity of the 10 compounds against Tribolium castaneum adults was tested. Gomisin J (6) exhibited activity at 1500?ppm concentration with 40.3% antifeeding index percentages. As for the dibenzocyclooctene lignans (compounds 1–3, 6), the number of methylenedioxies and the position of hydroxyl groups were the main factors to affect their antifeedant activities.     

1H and 13C NMR spectral assignments of pyridinium salts linked to a N‐9 or N‐3 adenine moiety

¹H and ¹³ C NMR spectral data of 13 new compounds containing a 4‐(dimethylamino)‐ or 4‐(pyrrolidin‐1‐yl)pyridinium moiety linked to the N‐9 or N‐3 nitrogen atom of an adenine moiety were assigned. 1D and 2D NMR experiments (DEPT, HSQC and HMBC) allowed the unequivocal identification of N‐9 and N‐3 isomers. Copyright © 2012 John Wiley & Sons, Ltd.     

Structure elucidation and NMR assignments for three anthraquinone derivatives from the marine fungus Fusarium sp. (No. ZH‐210)

The structure elucidations and complete ¹H and ¹³C NMR assignments are reported for three new anthraquinone derivatives: Fusaquinon A (1), B (2), and C (3) isolated from the fermentation medium of the marine fungus Fusarium sp. (No. ZH‐210). HREIMS, Fourier transform infrared absorption spectrometry (FT‐IR), NMR experiments including gCOSY, gHMQC, gHMBC, and NOESY were used for the determination of the structures and NMR spectral assignments. Preliminary pharmacological test showed that they exhibited low cytotoxic activity towards KB, KBv200, and MCF‐7 cell lines. Copyright © 2009 John Wiley & Sons, Ltd.     

1H and 13C NMR assignments of abietane diterpenes from Aegiphila lhotzkyana

An NMR study of one new and several known abietane diterpenes isolated from the roots of Aegiphila lhotzkyana is described. In addition to 1D NMR, several 2D shift‐correlated NMR pulse sequences (¹H–¹H‐COSY, NOESY, HMQC and HMBC) were used to establish all the structures, and unambiguously perform the ¹H and ¹³C chemical shift assignments of the new natural diterpene and three derivatives, the NMR data for which have not been reported previously. Revision of current data assignment for teuvincenone H is also suggested. Copyright © 2003 John Wiley & Sons, Ltd.     

Structure elucidation and NMR assignments for curcuminoids from the rhizomes of Curcuma longa

Thirteen curcuminoids (1–13) were isolated from the rhizomes of Curcuma longa. Among them, 1,5‐dihydroxy‐1,7‐bis(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (1), 1,5‐dihydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)‐7‐(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (2), 1,5‐dihydroxy‐1‐(4‐hydroxyphenyl)‐7‐(4‐hydroxy‐3‐methoxyphenyl)‐4,6‐heptadiene‐3‐one (3), and 3‐hydroxy‐1,7‐bis‐(4‐hydroxyphenyl)‐6‐heptene‐1,5‐dione (4) are new compounds, and 1‐(4‐hydroxyphenyl)‐7‐(3, 4‐dihydroxyphenyl)‐1, 6‐heptadiene‐3, 5‐dione (5) is isolated from natural sources for the first time. The structures of these compounds were elucidated by extensive spectroscopic analyses, especially 1D and 2D NMR spectroscopy. The ¹³C NMR data and complete ¹H and ¹³C NMR assignments of some known compounds are reported for the first time. In addition, the errors of ¹H and ¹³C assignments reported in the literature were corrected. Copyright © 2009 John Wiley & Sons, Ltd.     

Lyciumaside and Lyciumate: A New Diacylglycoside and Sesquiterpene Lactone from Lycium shawii

One new diacylglycoside named lyciumaside ( 1 ) and a new sesquiterpene lactone named lyciumate ( 2 ) were isolated from Lycium shawii Roem . & Schult . The structures of the two new compounds were elucidated based on 1D‐ (¹H‐ and ¹³C‐NMR and NOE) and 2D‐NMR (COSY, HSQC, and HMBC) spectroscopic techniques, and mass spectrometry (ESI‐MS). Preliminary evaluations demonstrated lyciumaside ( 1 ) possesses strong antioxidant activity with an IC₅₀ = 30 μg/ml (80% inhibition) while it was inactive in α‐glucosidase and urease enzymes assays.     

Structural elucidation and total assignment of the 1H and 13C NMR spectra of new chalcone dimers

Conventional 1D NMR methods and 2D shift‐correlated NMR experiments (COSY, HMQC, HMBC) were used for the structural elucidation and ¹H and ¹³C chemical shifts assignments of four new types of chalcone dimers isolated from Myracrodruon urundeuva. Copyright © 2003 John Wiley & Sons, Ltd.     

Lignans from the Bark of Magnolia kobus

The Et₂O‐soluble fraction from the bark of Magnolia kobus led to the isolation of two new lignans, (+)‐(7α,7′α,8α,8′α)‐3′,4,4′,5,5′‐pentamethoxy‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 1 ) and (+)‐(7α,7′α,8α,8′α)‐4,5‐dimethoxy‐3′,4′‐(methylenedioxy)‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 2 ), along with five known lignans 3 – 7 . Their structures were established on the basis of various spectroscopic analyses including 1D‐ (¹H, ¹³C, and DEPT) and 2D‐NMR (COSY, NOESY, HMQC, and HMBC) and by comparison of their spectral data with those of related compounds.