New Triterpenoid and Ergostane Glycosides from the Leaves of Hydrocotyle umbellata L.

Two new triterpenoid glycosides, together with two new ergostane glycosides, umbellatosides A–D ( 1 – 4 , resp.), have been isolated from the leaves of Hydrocotyle umbellata L. Their structures were established by 2D‐NMR spectroscopic techniques (¹H,¹H‐COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as 3β,22β‐dihydroxy‐3‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucuronopyranosyl]olean‐12‐en‐28‐oic acid 28‐O‐β‐D ‐glucopyranosyl ester ( 1 ), 3‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucuronopyranosyl]oleanolic acid 28‐O‐β‐D ‐glucopyranosyl ester ( 2 ), (3β,11α,26)‐ergosta‐5,24(28)‐diene‐3,11,26‐triol 3‐O‐(β‐D ‐glucopyranosyl)‐11‐O‐(α‐L ‐rhamnopyranosyl)‐26‐O‐β‐D ‐glucopyranoside ( 3 ), and (3β,11α,21,26)‐ergosta‐5,24(28)‐diene‐3,11,21,26‐tetrol 3‐O‐(β‐D ‐glucopyranosyl)‐11‐O‐(α‐L ‐rhamnopyranosyl)‐26‐O‐β‐D ‐glucopyranoside ( 4 ).     

New Steryl Esters of Fatty Acids from the Mangrove Fungus Aspergillus awamori

The polyhydroxylated ergostane‐type sterol 9 , its derivatives 10 – 15 , and the fatty acid esters 1 – 8 were isolated from a fungus strain which was collected from mangrove areas at Wenchang, Hainan Province, P. R. China, exhibited potent cytotoxic activity, and was identified as Aspergillus awamori. The structures of 1 – 15 were elucidated by spectroscopic and chemical methods. Among them, the six steryl esters 1 – 6 of fatty acids were new compounds, i.e., (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate ( 1 ), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate ( 2 ), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐oleate ( 3 ), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐linoleate ( 4 ), (3β,5α,6β,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate ( 5 ), and (3β,5α,6β,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate ( 6 ). The related known fatty acids stearic acid (=octadecanoic acid) and palmitic acid (=octadecanoic acid) were also obtained. A speculative biogenetic relationship of the metabolites is proposed. The known polyhydroxylated sterols and derivatives showed cytotoxic activities, in agreement with earlier reports. The cytotoxic activities against B16 and SMMC‐7721 cell lines of the new steryl esters 1 – 6 by the MTT method were weak.     

Highly Conjugated Ergostane‐Type Steroids and Aranotin‐Type Diketopiperazines from the Fungus Aspergillus terreus BCC 4651

Two new ergostane derivatives, 12β,15α,25,26‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 1 ) and 12β,15α,25,28‐tetrahydroxyergosta‐4,6,8(14),22‐tetraen‐3‐one ( 2 ), and a new aranotin‐type diketopiperazine, bisdethiobis(methylsulfanyl)apoaranotin ( 3 ), were isolated from the fungus Aspergillus terreus BCC 4651. The structures of the new compounds were elucidated by means of NMR spectroscopic and MS analyses.     

Sterols from the Stems of Momordica charantia

A new sterol, 5α,6α‐epoxy‐3β‐hydroxy‐(22E,24R)‐ergosta‐8,22‐dien‐7‐one ( 1 ), together with eight known sterols, 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8,22‐diene‐3β,7α‐diol ( 2 ), 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8,22‐diene‐3β,7β‐diol ( 3 ), 5α,6α‐epoxy‐(22E,24R)‐ergosta‐8(14),22‐diene‐3β,7α‐diol ( 4 ), 3β‐hydroxy‐(22E,24R)‐ergosta‐5,8,22‐trien‐7‐one ( 5 ), ergosterol peroxide ( 6 ), clerosterol ( 7 ), decortinol ( 8 ), and decortinone ( 9 ), were isolated from the stems of Momordica charantia. Their structures were elucidated by mean of extensive spectroscopic methods, including ¹H, ¹³C, 2D‐NMR and HR‐EI‐MS, as well as comparison with the literature data. Compounds 1 , 4 , 5 , 8 , and 91 were not cytotoxic against the SK‐Hep 1 cell line.     

Cyclodextrin‐modified capillary electrophoresis for achiral and chiral separation of ergostane and lanostane compounds extracted from the fruiting body of Antrodia camphorata

A CD‐modified capillary electrophoretic method has been developed for achiral and chiral analysis of seven bioactive compounds isolated from the fruiting body of Antrodia camphorata. Such important target analytes exhibit similar chemical structures and are known for their diverse properties including antioxidant and anticancer effects. The analytes were separated in 25 min using a pH 9.3, 20 mM sodium borate buffer containing 20 mM methyl‐β‐CD and 30 mM sulfobutylether‐β‐CD. With the exception of the optical isomer pairs (antcin B or zhankuic acid A, zhankuic acid C, and antcin A), the remaining bioactive compounds including the chiral pair antcin C were baseline‐separated. Analysis time was noticeably longer to baseline separate all of the above chiral pairs (～38 min) by adding 5% DMF to the running buffer. The migration order was reversed compared with the HPLC elution. More hydrophobic compounds complexed favorably with methyl‐β‐CD and emerged earlier in the electropherogram than their more hydrophilic counterparts which were strongly associated with sulfobutylether‐β‐CD. The simple capillary electrophoretic method developed was applicable for rapid separation and characterization of several important bioactive compounds isolated from the fruiting body of A. camphorata.     

Ergostane Steroids from Dysoxylum lukii

Phytochemical investigation of the 70% EtOH extract from the stem bark of Dysoxylum lukii led to the isolation of three new ergostane steroids, (3β)‐3,20‐dihydroxyergosta‐5,24(28)‐dien‐7‐one ( 1 ), (3β,4β,7α)‐ergosta‐5,24(28)‐diene‐3,4,7‐triol ( 2 ), and (3β,7α)‐3,20‐dihydroxyergosta‐5,24(28)‐dien‐7‐yl acetate ( 3 ), together with the known compound (3β,4β)‐ergosta‐5,24(28)‐diene‐3,4,20‐triol ( 4 ). Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR (COSY, HMQC, HMBC, and NOESY) analyses.