Lusianthrin and lusianthridin, two new stilbenoids, were isolated from the orchid Lusia indivisa. The structures of lusianthrin and lusianthridin were established from detailed spectral and chemical evidence. © 1990.

P L MAJUMDER

S LAHIRI

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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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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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

Lusianthrin and lusianthridin, two stilbenoids from the orchid Lusia indivisa

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

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

Callosin and callosinin, two new stilbenoids, were isolated from the orchid Agrostophyllum callosum, which also afforded, 4-hydroxy-3,5-dimethoxybenzoic acid, orchinol, 6-methoxycoelonin, imbricatin, flaccidin, oxoflaccidin, iso-oxoflaccidin, flaccidinin and agrostophyllin of previously known structures. Callosin was also isolated from another orchid, Coelogyne flaccida. The structures of callosin and callosinin were established as 2,6-dihyroxy-4,7-dimethoxy-9,10- dihydrophenanthrene and 2,6,7-trimethoxy-9,10-dihydro-5H-phenanthro [4,5-bcd]pyran-5-one, respectively, from spectral and chemical evidence. For ease of comparison of the spectral data the phenanthrene numbering system is used in this paper. © 1995.

Stilbenoids from the orchids Agrostophyllum callosum and Coelogyne flaccida

From the orchid, Arundina bambusifolia, were isolated two new stilbenoids, arundin and arundinin, besides p-hydroxybenzaldehyde, batatasin III, lusianthridin, flavanthrin, flavidin and the polyphenyl propanoid-malonate-derived compound 3,3′-dihydroxy-2,6-bis-(p-hydroxybenzyl)-5-methoxybibenzyl of previously known structures. Arundin and arundinin were shown to be 3-hydroxy-2,6-bis-(p-hydroxybenzyl)-5-methoxybibenzyl and 3,3′-dihydroxy-4-(p-hydroxybenzyl)-5-methoxybibenzyl, respectively, mainly from spectral evidence. © 1993.

Two stilbenoids from the orchid Arundina bambusifolia

Cirrhopetalanthrin, a dimeric phenanthrene derivative from the orchid Cirrhopetalum maculosum

Gymnopusin, the first naturally occurring phenanthrene derivative having a hydroxyl group at C-9, was isolated from the orchid Bulbophyllum gymnopus. It was shown to be 7,9-dihydroxy-2,3,4-trimethoxyphenanthrene (1a) mainly from the spectral data of the compound and those of its diacetyl (1b) and dimethyl ether (1c) derivatives. © 1988.

A ring-B oxygenated phenanthrene derivative from the orchid Bulbophyllum gymnopus

Flaccidin, a new 9,10-dihydrophenanthropyran derivative, was isolated from the orchid Coelogyne flaccida. It was shown to be 2,6-dihydroxy-7-methoxy-9,10-dihydro-5H-phenanthro[4,5-bcd]pyran mainly from spectroscopic evidence. © 1988.

Flaccidin, a 9,10-dihydrophenanthropyran derivative from the orchid Coelogyne flaccida

From the orchid Eria confusa were isolated two new polyoxygenated phenanthrene derivatives, confusarin and confusaridin, which were shown to be 2,7-dihydroxy-3,4,8-trimethoxyphenanthrene and 2,6-dihydroxy-3,4,7,8-tetramethoxyphenanthrene, respectively. © 1987.

Confusarin and confusaridin two phenanthrene derivatives of the orchid Eria Confusa

An amorphous phenanthrene, named nudol has been isolated from Eulophia nuda, Eria carinata and E. stricta. It was identified as 2,7-dihydroxy-3,4-dimethoxyphenanthrene. Synthesis of nudol and its dimethyl ether is described. © 1985.

Journal	Phytochemistry
Publisher	-
ISSN	0031-9422