Diterpenoid Alkaloids from Delphinium yunnanense

Three new diterpenoid alkaloids, along with eleven known alkaloids, were isolated from the whole herbs of Delphinium yunnanense. The new alkaloids include a rearranged‐type C₁₉‐diterpenoid alkaloid, named yunnanenseine A ( 1 ), and two hetisine‐type C₂₀‐diterpenoid alkaloids, named yunnanenseine B and C ( 2 and 3 , resp.). Their structures were elucidated by detailed NMR‐spectroscopic studies.     

Diterpenoid Alkaloids from Delphinium tatsienense

Three new C₂₀‐diterpenoid alkaloids, along with twenty‐two known alkaloids, were isolated from the whole herbs of Delphinium tatsienense. The new alkaloids include a vakognavine‐type C₂₀‐diterpenoid alkaloid, designated as tatsienenseine A ( 1 ), and two hetisine‐type C₂₀‐diterpenoid alkaloids, designated as tatsienenseines B ( 2 ) and C ( 3 ). Their structures were elucidated by IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR analyses.     

Pregnane‐Type Steroidal Alkaloids of Sarcococca saligna: a New Class of Cholinesterase Inhibitors

Phytochemical investigation of Sarcococca saligna by extensive bioassay‐guided fractionation resulted in the isolation of the pregnane‐type steroidal alkaloids 1 – 15 , i.e. of the five new compounds 1 – 5 and the ten known alkaloids 6 – 15 . The structures of the new alkaloids salignenamide C ( 1 ), salignenamide D ( 2 ), 2β‐hydroxyepipachysamine D ( 3 ), salignenamide E ( 4 ), and salignenamide F ( 5 ) were elucidated with the help of modern spectroscopic techniques, while the known alkaloids axillarine C ( 6 ), axillarine F ( 7 ), sarcorine ( 8 ), N³‐demethylsaracodine ( 9 ), saligcinnamide ( 10 ), salignenamide A ( 11 ), vaganine A ( 12 ), axillaridine A ( 13 ), sarsalignone ( 14 ), and sarsalignenone ( 15 ) were identified by comparing their spectral data with those reported earlier. Inhibition of electric‐eel acetylcholinesterase (EC 3.1.1.7) and horse‐serum butyrylcholinesterase (EC 3.1.1.8) by alkaloids 1 – 15 were investigated. These new cholinesterase inhibitors may act as potential leads in the discovery of clinically useful inhibitors for nervous‐system disorders, particularly by reducing memory deficiency in Alzheimer's disease patients by potentiating and effecting the cholinergic transmission process. These compounds were found to inhibit both enzymes in a concentration‐dependent fashion with the IC₅₀ values ranging from 5.21–227.92 μM against acetylcholinesterase and 2.18–38.36 μM against butyrylcholinesterase.     

New Diterpene Alkaloids from Aconitum sungpanense var. leucanthum

Five new C₁₉ diterpene alkaloids, leucanthumsines A ( 1 ), B ( 2 ), C ( 3 ), D ( 4 ), and E ( 5 ), were isolated from the Chinese medicinal herb Aconitum sungpanense var. leucanthum, together with the known C₁₉ diterpene alkaloids pseudaconine, neoline, 1‐O‐methyldelphisine, crassicaudine, chasmanine, talatisamine, indaconitine, ezochansmanine, and leueantine D. The structures of these new alkaloids were elucidated by HR‐MS and advanced NMR methods, including ¹H‐ and ¹³C‐NMR (DEPT), ¹H,¹H‐COSY, HMQC, and HMBC experiments.     

New Diterpenoid Alkaloids from Aconitum liangshanicum

One new C₁₉‐diterpenoid alkaloid, named liangshantine ( 1 ), and three new C₂₀‐diterpenoid alkaloids, liangshansines A–C ( 2 – 4 , resp.), as well as eight known compounds, were isolated from the roots of Aconitum liangshanicum. The structures of these new alkaloids were elucidated by spectroscopic methods.     

New C19－Diterpenoid Alkaloids from the Roots of Delphinium Giraldii

Three new C19-diterpenoid alkaloids, giraldines A (1), B (3) and C (4), were isolated from the roots of Delphinium giraldii Diels, together with three known C19-diterpenoid alkaloids, dihydrogadesine (5), tatsiensine (6) and siwanine A (7), as well as their structures were elucidated by chemical evidence and spectral analyses, including IR, MS, 1D NMR and 2D NMR.     

New Alkaloids from Aconitum vaginatum

Two new amide alkaloids, vaginatunine A and B ( 1 and 2 , resp.), and a new C₁₈‐diterpenoid alkaloid vaginatunine C ( 3 ), together with four known alkaloids, were isolated from the tubers of Aconitum vaginatum. Their structures were determined by means of spectroscopic analyses and comparison of the data with those reported previously.     

Three New C19‐Diterpenoid Alkaloids from Aconitum transsectum

Three new C₁₉‐diterpenoid alkaloids, named aconitramines A ( 1 ), B ( 2 ), and C ( 3 ), were isolated from Aconitum transsectum. By UV, IR, 1D‐ and 2D‐NMR, and MS analyses, their structures were elucidated as 18‐methoxyvilmoraconitine, 18‐demethoxydolichotine A, and 18‐demethoxydolichotine B. Compound 1 is the second known C₁₉‐diterpenoid alkaloid with a three‐membered ring formed by C(8), C(9), and C(10).     

Two New Bis‐alkaloids from the Aerial Part of Piper flaviflorum

Two new bis‐alkaloids, flavifloramides A ( 1 ) and B ( 2 ), as well as two known alkaloids, N‐trans‐feruloyltyramine ( 3 ) and paprazine ( 4 ), were isolated from the aerial part of Piper flaviflorum. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR techniques.     

Alkaloids from the Stems of Glycosmis pentaphylla

A new simple carbazole alkaloid, 4‐(7‐hydroxy‐3‐methoxy‐6‐methyl‐9H‐carbazol‐4‐yl)but‐3‐en‐2‐one ( 1 ), and two new dimeric carbazole alkaloids, bisglybomine B ( 2 ) and biscarbalexine A ( 3 ), together with seven known alkaloids, were isolated from the stems of Glycosmis pentaphylla. Their structures were elucidated by spectroscopic methods, especially 2D‐NMR techniques.     

交让木树皮中的新虎皮楠生物碱的结构研究

本文报道从虎皮楠科植物交让木的树皮中分到4个新的和7个已知的虎皮楠生物碱的结构研究。4个新生物碱分别命名为脱氧交让木碱（dehydroxymacropodumineA）(1), 4,21-脱乙酰-23-脱甲基-脱氧交让木胺（4,21-deacetyl-23-demethyl-deoxyyuzurimine） (2),7-氧杂--脱氧交让木胺（7-oxo-deoxyyuzurimine）(3),和4-乙酰氧-虎皮楠素B （4-acetoxydaphmanidinB）(4)。新化合物1-4的结构是通过仔细解析其波谱数据和与已知结构相关的化合物波谱数据比较而确定。脱氧交让木碱（dehydroxymacropodumineA）(1) 具有罕见的11元环的大环内酯结构,是从自然界中分到的第二个具有这一新颖结构特征的生物碱。     

Three New Indole Alkaloids from the Leaves of Kopsia officinalis

Three new indole alkaloids, 11,12‐de(methylenedioxy)danuphylline ( 1 ), methyl (2β,11β,12β,19α)‐6,7‐didehydro‐8,21‐dioxo‐11,21‐cycloaspidospermidine‐2‐carboxylate ( 2 ), and (2β,5β)‐aspidofractinin‐16‐ol ( 3 ) were isolated from Kopsia officinalis, together with 16 known compounds. Their structures were determined by spectroscopic methods. The isolated known compound (?)‐12‐methoxykopsinaline displayed antimanic effects in Drosophila, with an IC₅₀ value of 12.5 μg/ml.     

Novel Alkaloids from Stemona sessilifolia

Two new alkaloids, sessilifolines A ( 1 ) and B ( 2a ), were isolated from the stems of Stemona sessilifolia, together with three known alkaloids, tuberstemonine ( 3 ), sessilifoliamide A ( 4 ), and stemoninoamide ( 5 ). Their structures were established by mass‐spectrometric and spectroscopic methods, especially 2D‐NMR techniques.     

New Stephaoxocane Alkaloids from Stephania longa

Three new stephaoxocane‐type alkaloids, stephalonganines A–C ( 1 – 3 ), together with the known eletefine ( 4 ), were isolated from the whole plant of Stephania longa. Their structures were fully characterized spectroscopically, and the absolute configurations of the new alkaloids were assigned by comparison of their circular‐dichroism (CD) data with those of 1,2‐dihydrostephaoxocanine ( 5 ), in combination with 2D‐NMR experiments.     

Three New Pregnane Alkaloids from Pachysandra terminalis

Three new pregnane alkaloids, pachystermine C ( 1 ), pachysanamine A ( 2 ), and pachysanamine B ( 3 ), together with four known ones, pachystermine B ( 4 ), pachysamine A ( 5 ), (20S)‐20‐(dimethylamino)‐16α‐hydroxy‐3β‐(3′α‐isopropyl)lactam‐5α‐pregnan‐4‐one ( 6 ), and E‐salignone ( 7 ), were isolated from Pachysandra terminalis. The chemical structures of the new alkaloids were elucidated by spectroscopic methods. All the compounds were evaluated for their inhibitory activities against HL‐60, SMMC‐7721, A‐549, MCF‐7, and SW480 cell lines, some of the compounds showed stronger cytotoxicity for the test cell lines, especially compounds 2 , 3 , and 7 .     

Cytotoxic 5‐Hydroxyindole Alkaloids from the Marine Sponge Scalarispongia sp.

Three new 5‐hydroxyindole alkaloids ( 1 , 2 , 3 ) along with seven known analogs ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ) were isolated from a Dokdo marine sponge Scalarispongia sp. The elucidation of the structures of the new compounds by spectroscopic analyses indicated that these compounds were an indole glyoxylate ( 1 ), a mono‐indole analog of hyrtinadine A ( 2 ), and a symmetrical bis‐indole with pyridine linker ( 3 ). The comparison of IC₅₀ values for obtained compounds against a human leukemia cell line revealed that the bis‐indole structure is a requirement for cytotoxicity.     

Two New Cytotoxic Alkaloids from Mappianthus iodoides Hand.‐Mazz.

Two new alkaloids, mappine A ( 1 ) and mapposidic acid ( 2 ), together with eleven known compounds, were isolated from the stems of Mappianthus iodoides Hand.‐Mazz. Their structures were elucidated by means of spectroscopic and mass‐spectrometric analyses, particularly 1D‐ and 2D‐NMR spectroscopy. The cytotoxic activities of the two new alkaloids were also evaluated.     

Alkaloids from the Roots of Stemona tuberosa

Four new alkaloids, didehydrotuberostemonine A ( 1 ), stemoninone ( 2 ), tuberostemospiroline ( 3 ), and tuberostemonine L ( 4 ), together with seven known alkaloids, were isolated from the roots of Stemona tuberosa. Their structures were elucidated on the basis of spectroscopic analysis. The known alkaloids were identified as 2‐oxostenine ( 5 ), tuberostemonine ( 6 ), sessilifoliamide H ( 7 ), tuberostemonone ( 8 ), didehydrotuberostemonine ( 9 ), bisdehydrostemoninine ( 10 ), and tuberostemoamide ( 11 ).     

New Alkaloids from Hippeastrum papilio (Ravenna) Van Scheepen

A new phytochemical study of the indigenous Brazilian species Hippeastrum papilio is reported herein. Three novel Amaryllidaceae alkaloids were isolated, including hippapiline ( 1 ), papiline ( 2 ), and 3‐O‐demethyl‐3‐O‐(3‐hydroxybutanoyl)haemanthamine ( 3 ). Their structures were determined by physical and spectroscopic methods. In addition, the known alkaloids, haemanthamine ( 4 ), galanthamine ( 5 ), narwedine ( 6 ), 11β‐hydroxygalanthamine ( 7 ), apogalanthamine ( 8 ), and 9‐O‐demethyllycosinine B ( 9 ) were identified. The unusual cis‐B/C‐ring fusion for the new homolycorine representative hippapiline was ratified by NMR and CD spectroscopy.     

Two New Lycopodium Alkaloids from Lycopodium obscurum

Two new Lycopodium alkaloids, (+)‐cermizine D N‐oxide ( 1 ) and (8β)‐8‐(acetyloxy)obscurumine A ( 2 ), along with five known compounds, were isolated from the crude alkaloid portion of Lycopodium obscurum. Their structures were elucidated on the basis of spectroscopic data and chemical correlation. All of these alkaloids were tested in an assay for acetylcholine esterase (AChE) inhibitory activity.