M.S. Chadha

Isolation of ecdysterone from indian plants

Abstract Ecdysterone has been isolated from the following plants: Achyranthes aspera, Gomphrena celosioides, Trianthema portulacastrum and Sesuvium portulacastrum, the latter being one of the best sources for ecdysterone.

Tissue differentiation and plumbagin synthesis in variant cell strains of plumbago zeylanica L. in vitro

Abstract Chemical analysis of 3 different cell strains derived from stem explants of Plumbago zeylanica and cultured in vitro varied in pigmentation and morphology. The plumbagin content was highest in the anthocyanin-pigmented strain. The induction of roots in the nodular strain did not influence plumbagin synthesis. Chlorophyll induction in a non-pigmented strain was accompanied by the synthesis of β-carotene and trace amounts of plumbagin. The plumbagin content of variant cell strains in culture has been compared to that of isolated parts of the intact plant.

Hormonal control of steroid synthesis in Solanum xanthocarpum tissue cultures

Abstract Analysis of tissue cultures of Solanum xanthocarpum subjected to the influence of different plant hormones such as 2,4-D, IAA, IBA, kinetin and GA singly and in synergistic combinations showed changes in the steroidal content indicating chemical regulation by auxins.

Isolation of 5-hydroxy-3,6,7,3′,4′-pentamethoxy flavone from Vitex negundo

Abstract 5-Hydroxy-3,6,7,3′,4′-pentamethoxylflavone has been isolated from the leaves of Vitex negundo.

Insect moulting hormone from Achyranthes aspera

Abstract Ecdysterone (I) has been isolated from the methanolic extract of Achyranthes aspera roots.

A possible prebiotic synthesis of thymine: Uracil-formaldehyde-formic acid reaction☆

When uracil is reacted with formaldehyde and formic acid in dilute aqueous solutions at 100-140 degrees C, 5-hydroxymethyluracil (5-HMU), methylenebiuracil (MBU) and thymine are formed. It has been shown that 5-HMU is an intermediate in the formation of MBU and thymine. In the presence of formic acid, 5-HMU gives MBU, thymine and in some cases uracil. The formation of thymine is generally favoured under acidic conditions, although small amounts of this base could also be obtained when the reactions were carried out under mildly basic conditions. A hydride ion transfer mechanism is suggested for some of these reactions. These results have relevance to the formation of thymine under prebiotic conditions.

Stereoselective and versatile approach for the synthesis of gossyplure and its components

Abstract Efficient synthetic routes to gossyplure and its components (1a and 1b) were formulated. The three key units viz the alkynol 3, the bromide 5, and the alkanal 13 were derived from easily accessible starting materials. Alkylation of 3 with 5, and subsequent semihydrogenation followed by oxidation, provided the C11-alkenal 8 which was subjected to a stereocontrolled Wittig reaction with a C5-phosphonium salt, to yield directly the desired pheromone (1a + 1b). The synthesis of its individual components involved the manipulation via an acetylenic intermediate, viz the alkynol 14 which was obtained through alkylation of 3. A sequence of well-established reactions on 14, then provided the corresponding (E)- and (Z)-alkenylphosphonium salts which upon a (Z)-specific Wittig olefination with the C7-aldehyde (13), led to the stereoselective synthesis of 1a and 1b.

Morphogenetic and biosynthetic studies on tissue cultures of Atropa belladonna L.

Abstract The morphogenetic and biosynthetic ability of tissue cultures established from haploid and diploid plants of Atropa belladonna L. have been investigated. It was observed that the haploid tissue regenerated plantlets much more readily than did the diploids. The regenerants obtained in vitro were successfully transplanted to soil and grown to flowering stage. Haploid and diploid calli, regenerated young shoot buds and the in vitro obtained plants (at the stage of flowering) were subjected to chemical analysis. The total alkaloid contents in the calli and young shoot buds were very low (8–20 μg/g) as compared to the mature plant (1160 μg/g). Tropine, atropine, scopolamine and several unidentified Dragendorff-positive components were observed in the cultures. The alkaloid spectrum of the shoot buds was comparable to that of the unorganized calli. However, the relative proportion of atropine was more in the shoot buds as compared to the callus cultures. The regenerated flowering plants contained the principal belladonna alkaloids in quantities comparable to the plants raised from seeds.

A new convenient approach to peptide synthesis using a diselenide and a phosphine

Abstract A new and highly efficient method based on a redox reaction using diphenyl diselenide and tributylphosphine for the general synthesis of peptides is described. The side reaction due to selenophenol formation is overcome by using chalcone as a scavenger or by selective oxidation to diselenide.

Metabolism of cholesterol by callus culture of Holarrhena antidysenterica

Abstract A chemically defined medium was established for the growth of tissue cultures of Holarrhena antidysenterica . Administration of cholesterol-[4- 14 C] to 10-day-old callus yielded radioactive 24-methylenecholesterol, 28-isofucosterol, sitosterol, stigmasterol, and conessine, thereby indicating that the conversion of cholesterol into sitosterol is mediated through 24-methylenecholesterol and 28-isofucosterol in this system.