Uniflorin, a new steroidal compound of biogenetic importance, isolated from the orchid Coelogyne uniflora was shown to be 24-ethyl-4α,14α,24-trimethyl-9β,19-cyclo-cholest-25-en-3βyl cis-p-hydroxycinnamate from spectral and chemical evidence. © 1990.

P L MAJUMDER

(NEE ROY) S PAL

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

A steroidal ester from Coelogyne uniflora

Phytochemistry

Agrostophyllinol and agrostophyllinone, two new triterpenoids, were isolated from the orchid Agrostophyllum brevipes. Agrostophyllinone was also isolated from another orchid Agrostophyllum callosum. The structures of agrostophyllinol and agrostophyllinone were established as 24-methylene-lanosta-9(11)-en-3β-ol (5a) and 24-methylene-lanosta-9(11)-en-3-one (5c), respectively, from spectral and chemical evidence. The above triterpenoids are of considerable biogenetic importance. © 2002 Elsevier Science Ltd. All rights reserved.

Triterpenoids from the orchids Agrostophyllum brevipes and Agrostophyllum callosum

Coeloginanthridin, a 9,10-dihydrophenanthrene derivative, and coeloginanthrin, the corresponding phenanthrene analogue, were isolated from the orchid Coelogyne cristata which earlier afforded coelogin (1a) and coeloginin (1b). The structures of coeloginanthridin and coeloginanthrin were established as 3,5,7-trihydroxy-1,2-dimethoxy-9,10-dihydrophenanthrene (2a) and 3,5,7-trihydroxy-1,2-dimethoxyphenanthrene (2c), respectively, from spectral and chemical evidence including the conversion of coeloginanthridin triacetate (2b) to coeloginanthrin triacetate (2d) by dehydrogenation with DDQ. In the light of earlier reports on structurally similar compounds, 2a and 2c may have biological activities of phytoalexins and endogenous plant growth regulators. © 2001 Published by Elsevier Science Ltd.

Phenanthrene derivatives from the orchid Coelogyne cristata

Agrostophyllol and isoagrostophyllol, two novel diastereomeric 9,10- dihydrophenanthropyran derivatives isolated from the orchid Agrostophyllum callosum, were shown to have the structures 2,7-dihydroxy-6-methoxy-9,10- dihydro-5H-phenanthro[4,5-bcd]pyran-5(ax)ol (1l) and 2,7-dihydroxy-6-methoxy- 9,10-dihydro-5H-phenanthro[4,5-bcd]pyran-5(equat)ol (1n), respectively, from spectral and chemical evidence. 1l and 1n were shown to be the racemic mixtures of 1l' and 1l'', and 1n' and 1n'', respectively.

Tetrahedron

Agrostophyllol and isoagrostophyllol, two novel diastereomeric 9,10- dihydrophenanthropyran derivatives from the orchid Agrostophyllum callosum

Thunalbene, a new stilbene derivative, was isolated from the orchid Thunia alba which also afforded six known stilbenoids: batatasin-III, lusianthridin, 3,7-dihydroxy-2,4-dimethoxyphenanthrene, 3,7-dihydroxy-2,4,8- trimethoxyphenanthrene, cirrhopetalanthrin and flavanthrin. The structure of thunalbene, the first stilbene derivative isolated so far from an Orchidaceae plant, was established as 3,3'-dihydroxy-5-methoxystilbene from spectral and chemical evidence.

Thunalbene, a stilbene derivative from the orchid Thunia alba

Callosumin, callosuminin and callosumidin, three new stilbenoids, were isolated from the orchid Agrostophyllum callosum which earlier afforded, besides 4-hydroxy-3,5-dimethoxybenzoic acid, 10 other structurally related stilbenoids, viz. orchinol, 6-methoxycoelonin, imbricatin, flaccidin, oxoflaccidin, isooxoflaccidin, flaccidinin, agrostophyllin, callosin and callosinin. The structures of callosumin, callosuminin and callosumidin were established as 2,4,6,7-tetramethoxy-9,10 dihydrophenanthrene, 2,4,6,7- tetramethoxyphenanthrene and 2,7-dihydroxy-5-ethoxy(ax)-6-methoxy-9,10- dihydro-5H-phenanthro[4,5-bcd]pyran, respectively, from spectral and chemical evidence. Although in naming callosumidin the systematic numbering system has been adopted, for ease of comparison of the spectral results the phenanthrene numbering system for the compound and its structural analogues is used.

Three stilbenoids from the orchid Agrostophyllum callosum

From the orchid Eria convallarioides nudol, erianthridin, sitosterol and an uncharacterized fatty alcohol, along with a new steroidal compound, designated as erianol, which constitutes a modified intermediate in the biogenetic transformation of lanosterol to the steroidal system were isolated. The structure of erianol was established as 4α,24,24-trimethylcholesta-7,25-dien-3β-ol from spectral and chemical evidence. © 1989.

Erianol, a 4Î±-methylsterol from the orchid Eria convallarioides

Cyclootochilone and otochilone, two novel steroidal ketones of the orchids Otochilus porecta were shown to have the structures 1a and 2, respectively, from spectral and chemical evidence, 1a alone has also been obtained from the taxonomically related orchid Otochilus fusca. The significance of these compounds in the biogenetic transformation of lanosterol to steroids and the biogenetic sequence of the origin of 9,19- cyclopropane ring present in some terpenoids and steroids, as well as the mechanism of incorporation of two methyl groups at C-24 of some of these compounds were discussed. © 1985.

Structures of cyclootochilone and otochilone, two novel steroidal ketones of the orchids otochilus porecta and otochilus fusca

From the orchid Cirrhopetalum elatum was isolated a new triterpene of the cycloartane series, which was shown to be 24-methylenecycloartanyl p-hydroxycinnamate from spectral and chemical evidence. © 1985.

Journal	Phytochemistry
Publisher	-
ISSN	0031-9422