Parthasarathi Ghosh

Sterol compositions of seeds and mature plants of family cucurbitaceae

The sterol fractions of the unsaponifiable lipids obtained from 32 seed and mature plant (leaves and stems, pericarp of the fruit, and roots) materials from the 12 generaApodanthera, Benincasa, Citrullus, Coccinea, Cucumis, Cucurbita, Gynostemma, Lagenaria, Luffa, Momordica, Sechium andTrichosanthes, of the family Cucurbitaceae were investigated by gas liquid chromatography (GLC) on an OV-17 glass capillary column. Among the 23 sterols with Δ5-, Δ7- and Δ8-skeletons identified by GLC, the Δ7-sterols were found to be the major sterols of most of the Cucurbitaceae investigated. The seed materials contained 24-ethyl-Δ7-sterols possessing Δ25-bonds, i.e. 24-ethylcholesta-7,25-dienol and 24-ethylcholesta-7,22,25-trienol, whereas the mature plant materials contained 24-ethyl-Δ7sterols without a Δ25-bond, i.e. 24-ethylcholest-7-enol and 24-ethylcholesta-7,22-dienol, as the most predominant sterols, with a few exceptions. The isolation and identification of 24α-ethylcholesta-8(14),22-dienol from the aerial parts ofCucumis sativus also is described.

Compositions of triterpene alcohols of seeds and mature plants of family cucurbitaceae

Compositions of the triterpene alcohol fractions of the unsaponifiable lipids obtained from 28 seed and mature plant [aerial parts (leaves and stems), pericarp of the fruits, and roots] of 13 genera of the family Cucurbitaceae were determined by gas liquid chromatography (GLC) on an OV-17 glass capillary column. Among the 14 tetracyclic and pentacyclic triterpene alcohols identified, isomultiflorenol was found to be the major component for most of the seed materials. The abundance of this triterpene suggests that it may be a taxonomical marker of the seeds of Cucurbitaceae since only a few higher plants are known to contain isomultiflorenol. The mature plant materials of the Cucurbitaceae, on the other hand, were shown to contain either one or some of the common triterpene alcohols such asα- andβ-amyrins, cycloartenol and 24-methylenecycloartanol as the major triterpene constituents.

Sterols of some Clerodendrum species (verbenaceae): Occurrence of the 24α- and 24β-epimers of 24-ethylsterols lacking a Δ25-bond

Abstract The configurations at C-24 of 24-alkylsterols of six samples of Clerodendrum species (Verbenaceae) — the aerial parts of C. fragrans , C. inerme , C. infortunatum , C. scandens , and C. sipho - nanthus , and the seeds of C. infortunatum — were examined by NMR. All samples contained 24β-ethylsterols possessing a Δ25 -bond, clerosterol and 22-dehydroclerosterol, as the dominant sterol components. The other 24-ethylsterols lacking a Δ25 -bond, 24-ethyl-22-dehydrocholestanol, 24-ethylcholesterol, and 24-ethyl-22-dehydrocholesterol, which were present as minor components, were shown to be mixtures of the 24α- and 24β-epimers, with the 24α-epimers predominating in all cases. Four minor 24-methyl-sterols, 24-methylcholestanol, 24-methylcholesterol, 24-methyl-22-dehydrocholesterol, and 24-methyllathosterol, were shown to be C-24 epimeric mixtures, whereas two others, 24-methyl-22, 25-bis-dehydrocholesterol and 24-methyl-22-dehydrolathosterol, were found to be present only as the 24β-epimers. This is the first report of the occurrence of 24β-ethyl-22-dehydrocholestanol in higher plants.

The 24α- and 24β-epimers of 24-ethylcholesta-5,22-dien-3β-ol in two Clerodendrum species

Abstract 13 C NMR spectroscopy of the 24-ethylcholesta-5,22 E -dien-3β-ol isolated from the aerial parts of Clerodendrum fragrans and C. infortunatum demonstrated the occurrence of a minor amount of the 24β-epimer, poriferasterol, in addition to,the dominant 24α-epimer, stigmasterol. This was confirmed by 400 MHz 1 H NMR spectroscopy after enrichment of the 24p-epimer by repetitive reverse-phase HPLC. The ratios (24α:24β) of the C-24 epimeric mixtures were estimated to be 23:2 for the C. fragrans sterol and 19:1 for the C. infortunatum sterol.

Sterols of Cajanus cajan and three other leguminosae seeds

Abstract The occurrence of 24-epiclerosterol, three Δ 8(14) -sterols [24α- and 24β-methyl-5α-cholest-8(14)-en-3β-ols and 24α-ethyl-5α-cholest-8(14)-en-3β-ol] and four 14α-methyl-Δ 9(11) -sterols [14α,24α- and 14α,24β-dimethyl-5α-cholest-9(11)-en-3β-ols, 14α-methyl-24α-ethyl-5α-cholest-9(11)-en-3β-ol and 14α-methyl-24β-ethyl-5a-cholesta-9(11),25-dien-3β-ol] has been demonstrated in the seeds of four Leguminosae species, Cajanus cajan , Cicer arietinum , Pisum sativum and Vigna mungo . These compounds were minor sterol constituents. In addition, 24α-ethyl-5α-cholest-9(11)-en-3β-ol and 24-methylenepollinastanol were isolated and identified from V. mungo seeds. Sitosterol was the principal sterol in all of the four Leguminosae seeds investigated.

24β-methylcholesta-5,22E,25-trien-3β-ol and 24α-ethyl-5α-cholest-22E-en-3β-ol from Clerodendrum fragrans

Abstract Two minor sterols isolated from Clerodendrum fragrans were identified as 24β-methylcholesta-5,22E,25-trien-3β-ol and 24α-ethyl-5α-cholest-22E-en-3β-ol of which the former has so far been detected only in a marine sponge. The other sterols identified in the plant were clerosterol, 22E-dehydroclerosterol and several other common sterols.

A coumarin from Limonia acidissima

Dihydrosuberenol, a new coumarin, was isolated from the methanol extract of the defatted root-bark of Limonia acidissima. Its structure has been es

Triterpene alcohols and 3-oxo steroids of nine leguminosae seeds

Abstract The seeds of nine Leguminosae plants were investigated for their triterpene alcohol constituents. This led to the isolation and identification of 25 triterpene alcohols including one new compound, 24Z-ethylidene-24-dihydroparkeol, and three series of skeletal double bond isomers of lanostane-type compounds, 9β, 19-cyclolanostanes, and Δ 8 - and Δ 9 (11)-lanostenes. The occurrence of eight 3-oxo steroids was also demonstrated. β-Amyrin was the principal triterpene alcohol found in five of the Leguminosae seeds investigated.

24,24-Dimethyl-25-dehydrolophenol, a 4α-methylsterol from Clerodendrum inerme.

Abstract The structure of a new 4α-methylsterol isolated from the aerial parts of Clerodendrum inerme has been shown to be 4α,24,24-trimethyl-5α-cholesta-7,25-dien-3β-ol (24,24-dimethyl-25-dehydrolophenol) based mainly on the 1 H NMR spectroscopic comparison with known compounds. In addition 24β-ethyl-25-dehydrolophenol and two other common 4α-methylsterols were isolated and identified.

(22Z,24S)-Stigmasta-5,22,25-trien-3β-ol and other novel sterols from Clerodendrum scandens: first report of the isolation of a cis-Δ22-unsaturated sterol from a higher plant

(22Z,24S)-Stigmasta-5,22,25-trien-3β-ol was isolated from Clerodendrum scandens(Verbenaceae). It is only the second example of a naturally occurring Z-Δ22-unsaturated sterol. Four other novel sterols were isolated from the same source, viz.(24S)-5α-stigmast-25-en-3β-ol, (22E,24S)-5α-stigmasta-22,25-dien-3β-ol, 24-methylergosta-5,25-dien-3β-ol, and (24S)-14α-methyl-5α-stigmasta-9(11),25-dien-3β-ol. All structures were determined by chemical and spectroscopic methods.