Satyesh C. Pakrashi

A clerodane diterpene and other constituents of Clerodendron inerme

Abstract A new clerodane diterpene clerodermic acid was isolated from Clerodendron inerme and the structure deduced from spectral data. The known compounds friedelin, 5-hydroxy-7,4′-dimethoxyflavone, salvigenin, acacetin and apigenin were also found.

Two isomeric flavanones from vitex negundo

Abstract Two new flavanoids, characterized as 5,3′-dihydroxy-7,8,4′-trimethoxyflavanone and 5,3′-dihydroxy-6,7,4′-trimethoxyflavanone, have been isolated from the leaves of Vitex negundo.

Studies on Indian medicinal plants—XXVIII : Sesquiterpene lactones of Enhydra fluctuans Lour. Structures of enhydrin, fluctuanin and fluctuadin

Abstract The structures of enhydrin (2) and the co-occurring sesquiterpene lactones, viz. fluctuanin (3) and fluctuadin (4) isolated from Enhydra fluctuans Lour have been established. The stereochemistry of enhydrin has been suggested from NMR data. Selective hydrolysis of the acetate and the glycidate group in 2 yielded the alcohols 11 and 16 indicating acyl migration during their formation. Acetylation of 11 led further to acetolysis of the glycidate ester function to afford the diacetate 17. The location of the two acyl groups in 2 (and also in 3 and 4) still remain to be settled.

An N-glycoside and steroids from Aristolochia indica

Abstract A phenanthrene derivative, aristololactam N-β- d -glucoside, and the steroids 3β-hydroxy-stigmast-5-en-7-one and 6β-hydroxy-stigmast-4-en-3-one have been isolated from Aristolochia indica.

A neolignan and sterols in fruits of Solanum sisymbrifolium

A new neolignan, designated as sisymbrifolin, and carpesterol were isolated from the berries of Solanum sisymbrifolium. Their structures were established mainly on the basis of 2D NMR analyses.

Triterpenoid prosaponins from leaves of Maesa chisia var. angustifolia

Abstract Acid hydrolysis of the saponin fraction of the leaves of Maesa chisia var. angustifolia yielded a monoglucoside fraction besides camelliagenin A as a minor constituent. The glucose moiety of the former could be removed by hydrolysis by Smith degradation to yield two new acylated triterpenoids characterised as 16α- O -acetyl-22α- O -angeloyl-camelliagen A and 16α- O -acetyl-22α- O -(2′-methylbutyroyl)-camelliagenin A as well as camelliagenin A and its 22α,28-glycolaldehyde acetal. The possibility of the later acetal derivative being an artefact could not, however, be ruled out.

Simple aromatic amines from justicia gendarussa. 13C NMR spectra of the bases and their analogues

Abstract Four simple 0-disubstituted aromatic amines have been isolated from the leaves of Justicia gendarussa Burm and characterized as 2-amino benzyl alcohol (3), 2-(2′-amino-benzylamino) benzyl alcohol (4) and their respective 0-methyl ethers 1 and 2 from 1H NMR and mass spectral analyses of the bases and their acetates. Structures 3 and 4 have also been confirmed by synthesis. Intramolecular hydrogen bonding (cf. 9, 13 and 14) has been envisaged to explain the unexpected shielding of -CH2-OH carbon signals of 3 4 on acetylation and upfield displacement of -CH2-N signal of 2a vs 4a in their 13C NMR spectra in CDCl3 solution 1JCH values have been found to be useful for the assignment of aromatic methine carbon signals in o-disubstituted compounds. Part 68 of the series Studies on Indian medicinal plants. For Part 67, see P. K. Dutta, D. Bagchi and S.C. Pakrashi, Indian J. Chem. in press.

Isolation and structure of wallichoside, a novel pteroside from Pteris wallichiana

Abstract Wallichoside has been isolated from the rhizomes of Pteris wallichiana and its structure and absolute configuration has been established as the 3-β- d -glucoside of 2 S , 3 S -pterosin C on the basis of UV, IR, NMR and MS data of wallichoside and its derivatives.

Solanolide, a steroid lactone sapogenin from Solanum hispidum☆

Abstract Solanolide, a new C 22 steroid lactone sapogenin isolated from the leaves of Solanum hispidum Pers., has been characterized as 3β, 6α, 16β-trihydroxy-5α-pregnane-20 S -carboxylic acid (22, 16)-lactone from 1 H and 13 C NMR analyses and correlation with neochlorogenin.

Lipids and fatty acids of the horseshoe crabsTachypleus gigas andCarcinoscorpius rotundicauda

Total lipids from hepatopancreas of the horseshoe crabs,Tachypleus gigas andCarcinoscorpius rotundicauda, obtained in 7.6 and 3.3% wet weight respective yields, were fractionated by various chromatographic techniques and identified by gas-liquid chromatography and spectroscopic methods. Fatty acid-containing lipids were rich in 16∶0 (8.0–25%), 18∶1ω9 (6.9–22%) and 18∶2ω6 (6.8–18.5%); appreciable amounts of 16∶1ω7, 18∶3ω3, 20∶5ω3 and 22∶6ω3 were also present. The level of 26∶0 in the hydrocarbon fractions was unusually high (64 and 68%). Carbon chain lengths of major wax esters were 44, 46 and 48 forT. gigas and 38, 40 and 42 forC. rotundicauda. 1-O-Alkyl diglycerides were 7.2 and 9.1% of the total lipids in the two species and contained 14∶0(20%), 16∶0(60%) and 18∶0(20%) alkyl chains along with a relatively higher percentage (32–35%) of saturated fatty acids. High levels of cholesterol (>50% of total sterol) in the free and combined state were encountered in both samples, phospholipid contents being 40 and 35%, respectively, and contained highest levels of unsaturated fatty acids.