Isolation, structure elucidation and synthesis of 1-deoxyforskolin

Khandelwal, Y.; Jotwani, B. R.; Inamdar, P. K.; Souza, N. J. De; Rupp, R. H.

doi:10.1016/0040-4020(89)80107-3

Cited by 13 publications

(8 citation statements)

References 13 publications

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“…According to these spectral data, 1 was considered to be a 8,13-epoxy-labd-14-en-11-one diterpene. [1][2][3][4][5][8][9][10][11] The 1 H-NMR signal at d 5.71 (1H, dd, Jϭ4.0, 2.4 Hz) was assigned to H-6 by its coupling constants. 13,14) The chemical shifts of H-6 and C-6 suggested that Pharmacy, Meijo University; Tempaku, Nagoya 468-8503, Japan.…”

Section: Resultsmentioning

confidence: 99%

Diterpenes from Coleus forskohlii (WILLD.) BRIQ. (Labiatae)

Shan

Liu

et al. 2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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Coleus forskohlii (WILLD.) BRIQ. (Labiatae) has been used for medical treatment in Hindu and Ayurvedic traditional medicine from ancient times. 1) Since its major constituent forskolin was discovered to have positive inotropic, antihypertensive, and adenylatecyclase-stimulating activities, it has ever aroused a great deal of scientific interest, and many 8,13-epoxy-labd-14-en-11-one diterpenes have been obtained.1-11) The plant was subsequently found in Yunnan Province of China, while the major diterpene was determined to be coleonol B.10,11) So as to discover more novel and active compounds, further examination of the polar fraction of the whole plant extract has been carried out and yielded two new diterpene glycosides and a sesquiterpene in our earlier research.12) Continuing work yielded three other new diterpene glycosides forskoditerpenosides C, D, and E (1-3) and a diterpene forskoditerpene A (4). Complete NMR data studies on each compound were performed unambiguously to determine the structures of the compounds and to assign all the proton and carbon resonances. The isolation and structural elucidation of them are reported below. Forskoditerpenosides C, D, and E (1-3) were tested for their effects on isolated guinea pig tracheal spirals in vitro. Results and DiscussionAir-dried whole plants of C. forskohlii were extracted with EtOH three times. The concentrated extract was dissolved in water and successively extracted with petroleum ether (60-90°C) and n-BuOH. The n-BuOH soluble fraction was extracted with H 2 O in reflux and the combined solution was separated by means of various chromatographic procedures to afford four labdane diterpenes (1-4). . According to these spectral data, 1 was considered to be a 8,13-epoxy-labd-14-en-11-one diterpene. [1][2][3][4][5][8][9][10][11] The 1 H-NMR signal at d 5.71 (1H, dd, Jϭ4.0, 2.4 Hz) was assigned to H-6 by its coupling constants. 13,14) The chemical shifts of H-6 and C-6 suggested that Pharmacy, Meijo University; Tempaku, Nagoya 468-8503, Japan. Received August 6, 2007; accepted September 25, 2007 Three new minor labdane diterpene glycosides, forskoditerpenoside C, D, and E (1-3), and a novel labdane diterpene forskoditerpene A (4) were isolated from the ethanol extract of the whole plant of Coleus forskohlii. Their structures and relative stereochemistry were elucidated on the basis of extensive spectroscopic analyses including 1D-, 2D-NMR, and HR-ESI-MS experiments. Compounds 1-3 showed an unusual 8,13-epoxy-labd-14-en-11-one glycoside pattern. They showed relaxative effects on isolated guinea pig tracheal spirals in vitro. Compound 4 with a cyclopropyl, confirmed by a single-crystal X-ray diffraction determination, is the first known labdane derivative with a spiro element.

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Section: Resultsmentioning

confidence: 99%

Diterpenes from Coleus forskohlii (WILLD.) BRIQ. (Labiatae)

Shan

Liu

et al. 2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…(H-134, DSM 3205) was the only microorganism that offered the desired 1, 9-dihydroxylation (3) [15], though in limited yield (0.76%). Mortierella isabellina (ATCC 160074) [16] and Neurospora crassa (ATCC 10336) [17] provided a 1 -hydroxylation, yielding 9-deoxyforskolin (4), a minor metabolite of C. forskohlii that could be converted to forskolin (1) by chemical methods [18] (Fig. 2).…”

Section: Forskolin and Other Natural Manoyl Ox-idesmentioning

confidence: 99%

“…The aim of these biotransformation processes was to get compounds with a functionalization similar to that of forskolin (1). The substrates employed were jhanol, (18) (18-hydroxymanoyl oxide) and jhanidiol (19), a 1 -hydroxyl derivative, both isolated from a Venezuelan plant [25], and 1-oxo-jhanol (20), a major metabolite obtained from the incubation of jhanidiol (19) with G. fujikuroi, or chemically from jhanol (18).…”

Section: Forskolin and Other Natural Manoyl Ox-idesmentioning

confidence: 99%

Manoyl-Oxide Biotransformations with Filamentous Fungi

Garcı́a-Granados¹,

Martı́nez²,

Parra³

et al. 2007

COC

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Microbial transformations of manoyl oxides by filamentous fungi have been used to introduce hydroxyl groups, regio-and stereoselectively, into substrates at positions difficult to achieve by chemical means. The principal objective of most papers published in this field has been to produce new, highly oxygenated, bioactive manoyl-oxide compounds that present a large diversity of biological properties. The manoyl oxides most frequently studied at present are forskolin and its derivatives, the pharmacological activity of which is related to their ability to activate AC (adenylate cyclase), thus generating an increase in intracellular cAMP (cyclic adenosine monophosphate). The microbial hydroxylation of forskolin and 1,9-dideoxyforskolin has been extensively studied, using the fungi Scopuloriopsis sp., Syncephalastrum sp., Neurospora crassa, Mortierella isabellina and several Aspergillus sp.. Other biotransformation studies of natural manoyl oxides and hemi-synthetic enantio derivatives, carried out via the biomimetic cyclization of ent-8 -hydroxylabda-13(16),14-dienes, have used filamentous fungi Curvularia lunata, Cunninghamella elegans, Fusarium moniliforme, Gibberella fujikuroi, Gliocladium roseum, Mucor plumbeus, Rhizopus nigricans and Neurospora crassa. In some cases, the new hydroxylations were introduced at the same positions as in natural forskolin, yielding some noteworthy products that show biological activities.

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“…[2,7] 1,9-Dideoxyforskolin (3) has been synthesized starting from (E,E)-farnesol [8] as well as the natural products larixol [9] and ptychantin A, [10] and has itself been used as the starting material for the preparation of 1-deoxyforskolin (2). [7] Figure 1. Structures of forskolin (1), 1-deoxyforskolin (2) and 1,9-dideoxyforskolin (3).…”

Section: Synthesismentioning

confidence: 99%

Synthesis and Pharmacological Properties of New Tetracyclic Forskolin Analogues

et al. 2009

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New tetracyclic analogues of forskolin have been prepared by derivatization of the natural product. Treatment of a forskolin-derived cyclic thionocarbonate with 1,3-dimethyl-2-phenyl-1,3,2-diazaphospholidine resulted in the formation of a seven-membered cyclic carbonate derivative by an unprecedented rearrangement of an intermediate dialkoxycarbene or 1,3-dipole, whereas radical deoxygenation was followed by intramolecular cyclization with the double bond to form a third analogue. Two of the new analogues were investigated

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Isolation, structure elucidation and synthesis of 1-deoxyforskolin

Cited by 13 publications

References 13 publications

Diterpenes from Coleus forskohlii (WILLD.) BRIQ. (Labiatae)

Diterpenes from Coleus forskohlii (WILLD.) BRIQ. (Labiatae)

Manoyl-Oxide Biotransformations with Filamentous Fungi

Synthesis and Pharmacological Properties of New Tetracyclic Forskolin Analogues

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