Vadali Lakshmana Rao

Five diterpenoids (agallochins A-E) from the mangrove plant Excoecaria agallocha Linn.

Chemical examination of the hexane extract of the roots of Excoecaria agallocha Linn collected from the Godavari estuary resulted in the isolation of altogether eleven diterpenoids of which five (1-5) are new. The structures of the new diterpenoids have been elucidated by a study of their physical and spectral (UV, IR, 1H, 13C, DEPT, 1H-1H COSY, NOESY, HMQC, HMBC and MASS) data as 3-oxo-ent-13epi-8(13)-epoxy-15-chloro-14-hydroxylabdane (1), ent-15-chloro-13,14-dihydroxylabd-8(9)-en-3-one (2), ent-15-chloro-labd-8(9)ene-3alpha,13,14-triol (3), ent-11beta-hydroxy-8(14),15-isopimaradien-3-one (4), 8,13-epoxy-3-nor-2,3-seco-14-epilabden-2,4-olide (5). The six known diterpenoids have been characterised respectively as ent-3-oxo-13-epi-manoyl oxide (6), ent-3beta-hydroxy-13-epi-manoyl oxide (7), (13R,14S)-ent-8alpha,13;14,15-diepoxy-13-epi-labdan-3-one (8), ent-16-hydroxy-3-oxo-13-epimanoyl oxide (9), ent-15-hydroxylabda-8(17),13E-dien-3-one (10), labda-8(17),13E-diene-3beta,15-diol (11) by a comparative study of their spectral data with the literature values.

Seco diterpenoids from Excoecaria agallocha L.

Chemical examination of the ethyl acetate solubles of the CH(3)OH:CH(2)Cl(2) (1:1) extract of the roots of Excoecaria agallocha L. collected from Godavary estuary resulted in the isolation of three more new diterpenoids, agallochins M-O (1-3). The structures of the new diterpenoids were elucidated by a study of their physical and spectral data as methyl ent-13-epi-8,13-epoxy-4,6alpha-dihydroxy-3,4-secolabd-14-en-3-oate (1), methyl ent-13-epi-8,13-epoxy-2,3-secolabd-14-en-2,11-olid-3-oate (2), and methyl ent-17-hydroxy-3,4-secokaura-4(19),15-dien-3-oate (3).

Rhizophorin A, a novel secolabdane diterpenoid from the Indian mangrove plant Rhizophora mucronata.

Abstract The ethyl acetate extract of Rhizophora mucronata furnished rhizophorin A, a novel secolabdane diterpenoid, (6R,11S,13S)-6,11,13-trihydroxy-2,3-seco-14-labden-2,8-olide-3-oic acid (1).

New beyerane and isopimarane diterpenoids from Rhizophora mucronata

Chemical examination of the ethyl acetate extract of the roots of Rhizophora mucronata collected from Mangalore Coast resulted in the isolation of three more new diterpenoids, rhizophorins C-E ( 1 - 3 ) in addition to the two, rhizophorin A, (6 R ,11 S ,13 S )-6,11,13-trihydroxy-2,3-seco-14-labden-2,8-olid-3-oic acid, and rhizophorin B, ent -3 g; ,20-epoxy-3 f; ,18-dihydroxy-15-beyerene, recently reported. The structures of the new diterpenoids have been elucidated by a study of their physical and spectral data as 17-hydroxybeyer-15-en-3-one ( 1 ), 3 g; ,17-diacetoxy-15-beyeren-2-one ( 2 ) and 3 g; ,6 f; -diacetoxy-8(14),15-isopimaradien-2-one ( 3 ).

Agallochins J-L, New Isopimarane Diterpenoids from Excoecaria Agallocha L

The ethyl acetate extract of Excoecaria agallocha L. furnished three more new isopimarane diterpenoids, 11 f ,14 f -dihydroxy-7,15-isopimaradien-3-one, agallochin J ( 1 ), 3 f ,11 f ,14 f -trihydroxyisopimara-7,15-diene, agallochin K ( 2 ), and 6 f ,14 f ,17-trihydroxy-7,15-isopimaradien-3-one, agallochin L, ( 3 ).

Trocheliophorin: A novel rearranged sesquiterpenoid from the Indian Ocean soft coral Sarcophyton trocheliophorum

A novel rearranged sesquiterpenoid, trocheliophorin (1) has been isolated from the soft coral Sarcophyton trocheliophorum besides the known compounds, sarcophytin, methyl arachidonate, and two polyhydroxy steroids (24S)-24-methylcholestane-3β,5α,6β,25-tetrol-25-monoacetate and (24S)-24-methylcholestane-3β,5α,6β,25-tetrol. The structure of the new sesquiterpenoid was elucidated by a study of its spectral data.

A New Spiroketal Steroid from Gorgonella Umbraculum

A new spiroketal steroid ( 2 ) was isolated from the Indian Ocean gorgonian, Gorgonella umbraculum besides the known briarane diterpenoids, juncellin, umbraculides A and D. The new steroid was characterised as 22-acetoxy-3,25-dihydroxy-16-24,20-24-bisepoxy-(3 g , 16 f , 20 S , 22 R , 24 S )-cholest-5-ene ( 2 ) by a study of its spectral data.