Excoecarins D, E, and K, from <i>Excoecaria agallocha</i>

Konishi, Tenji; Konoshima, Takao; Fujiwara, Yasuhiro; Kiyosawa, Shiu

doi:10.1021/np990366t

Cited by 54 publications

(43 citation statements)

References 12 publications

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“…The 1 H-and 13 C-NMR spectra of 1 were similar to those of excoecarin D (10) 16) which was assigned to be 3a,18-dihydroxy-3b,20-epoxybeyer-15-ene, except that the methine proton at C-2 was substituted by a hydroxyl group. This was confirmed by a heteronuclear multiple-bond coherence (HMBC) experiment (Fig.…”

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confidence: 71%

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Three Diterpenoids (Excoecarins V1-V3) and a Flavanone Glycoside from the Fresh Stem of Excoecaria agallocha

Konishi

Yamazoe

Kanzato

et al. 2003

CHEMICAL & PHARMACEUTICAL BULLETIN

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Excoecaria agallocha LINN. (family Euphorbiaceae) is distributed on seashores and edge-mangroves throughout tropical Africa, Asia, and northwest Australia.1) The Excoecaria genus is well known to contain skin irritants, called irritant Excoecaria factors. In traditional Thai medicine, the bark and wood of the plant is used to treat flatulence. 2,3) In Sri Lanka, the smoke of the burning wood is used in the treatment of leprosy, and the root, when pounded with ginger, as an embrocation for swollen hands and feet.4) The milky latex exuded from the bark of E. agallocha may cause blindness or blistering of the skin.2,3) This latex has been used as a poison for fish by adding it to water and to poison arrowheads. The piscicidal constituent excoecariatoxin characterizing the daphnane diterpene ester and some related compounds have been obtained from the twigs, bark, and latex of Excoecaria agallocha in Japan and Thailand, respectively.2,3,5) Daphnaneand tigliane-type diterpene esters are known to be skin irritants and tumor promoters. 2,3)Previously we reported the isolation and structural elucidation of many diterpenoids from the resinous wood of this plant, 6) as well as their inhibitory effect on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-Otetradecanoylphorbol-13-acetate (TPA) in Raji cells. 7) In our search for bioactive compounds from plants of the Euphorbiaceae, we isolated three new diterpenoids, excoecarins V1-V3 (1-3) and a new flavanone glycoside (7) with five known compounds, ent-atisane-16a-ol (4) [8][9][10][11] and ent-2,3-secobeyer-15-ene-2,3-dioic acid (5), 12) ent-15,18-dihydroxylabda-8(17),13E-diene (6), 13) methyl 3,4,5-trihydroxybezoate (8), 14) and 3,4,5-trimethoxyphenol 1-O-b-D-(6-galloyl)-glucopyranoside (9) 15) from the fresh stem of E. agallocha collected in Okinawa. In this paper, we describe the stereochemistry of the new diterpenoids (1-3) and flavanone glycoside (7).Excoecarin V1 (1) Table 2). Two of the eight methylene carbons showed lower-field chemical shifts at d 65.1 and 67.3. We therefore concluded that 1 may be a beyerane-type diterpenoid with a ketal group and primary and secondary hydroxyl groups.The 1 H-and 13 C-NMR spectra of 1 were similar to those of excoecarin D (10) 16) which was assigned to be 3a,18-dihydroxy-3b,20-epoxybeyer-15-ene, except that the methine proton at C-2 was substituted by a hydroxyl group. This was confirmed by a heteronuclear multiple-bond coherence (HMBC) experiment (Fig. 1). The relative stereochemistry of 1 was assigned on the basis of the nuclear Overhauser effect (NOE) correlations. In the NOE difference NMR experiments, irradiation at d 3.61 (H 2 -20) and 3.67 (H 2 -20) enhanced the signal intensities of H-2 and H-15, respectively. NOEs were also observed between H-5 and H-18 and between H 3 -17 and H-14, H-16. (Fig. 2) These data suggested that the structure of 1 had the same relative conformation as excoecarin D (10). To determine the absolute configuration of C-2 in 1, a modified Mosher's method 17,18) was applied following...

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confidence: 71%

“…3). The optical rotation of 1 showed a negative sign, similar to that of excoecarin D. 16) Consequently, the structure of 1 was assigned to be 2a,3a,18-trihydroxy-3b,20-epoxybeyer-15-ene.…”

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confidence: 82%

Three Diterpenoids (Excoecarins V1-V3) and a Flavanone Glycoside from the Fresh Stem of Excoecaria agallocha

Konishi

Yamazoe

Kanzato

et al. 2003

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…The EtOAc fraction (110 g) was chromatographied on a silica gel column with a gradient CHCl 3 -MeOH solvent system to afford ten fractions (Fr. [1][2][3][4][5][6][7][8][9][10]. Purification of some parts of the fractions was reported in our previous report.…”

Section: Methodsmentioning

confidence: 99%

“…and 13 C-NMR signal 5,7,8) showed the presence of beyer-15-ene skeleton in the structure. So compound 1 should be composed of a (Z)-p-coumaroyl and a beyer-15-ene units through an ester linkage.…”

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confidence: 96%

Beyerane Derivatives and a Sesquiterpene Dimer from Japanese Cypress (Chamaecyparis obtusa)

Gao

Muto

et al. 2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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Social problems resulting from aging and degeneration of brain function have drawn attention around the world and especially in Japan. Biologically active constituents from plant resources are expected to suppress the development of these problems. We have studied various biologically active constituents from woody plants collected in the Chugoku area of Japan.1-3) In our previous work, the ethyl acetate (EtOAc) soluble fraction of Japanese Cypress (Chamaecyparis obtusa) showed neurite outgrowth-promoting activity on neuronal PC12 cells, and we isolated two novel compounds, 9-O-acetoxydihydrosesamin and a lignan-sesquiterpene conjugate, together with eleven known compounds, and some of the compounds showed potent neurite outgrowth activity. 4) In order to find more new constituents from this fraction, further chemical investigations of the residual fraction were carried out and four new beyerene type derivatives 1-4 (named obtsurins A-D) and a new sesquiterpene dimer ent-cryptomeridiol-4-yl-hinokiate (5), were obtained. Their structures were determined by means of spectral analysis including 2D-NMR and high-resolution (HR)-MS. This paper deals with the isolation and structural elucidation of the new compounds from C. obtusa.

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“…Previous phytochemical investigation studies of E. agallocha leaves revealed that the presence of diterpenoids, triterpenoids, flavonoids, alkaloids, anthraquinone, phytosterol, fixed oil, tannin, phorbole esters, free amino acids, mucilage, glycosides, carbohydrates, and lignin [55,56]. Novel Exoecarin D, E and F diterpenoid from Leaves of E. agallocha and their structure depicted as 3α,18-dihydroxy-3β,20-epoxybeyer-15-ene, (15R,16S)-ent-15,16-epoxybeyeran-3-one and ent-3β-hydroxykaur-16-en-2-one using NMR and X-ray analytical techniques [57]. Additionally, 14-taraxeren-3-one, dibutyl phthalate, phaeophytin A, betulin, beta rosasterol, betulinic aicd oleanolic and ursolic acid also identified from EA [58].…”

Section: Chemical Composition Of E Agallochamentioning

confidence: 99%

Insight on Excoecaria agallocha: An Overview

Kaliamurthi¹,

Selvaraj²

2016

Nat Prod Chem Res

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Excoecaria agallocha is a milky mangrove widely distributed in Indian coastal regions. This review article explains chemical composition, pharmaceutical and environmental applications of E. agallocha. There are 20 different polyphenols, 15 terpenoids and more than 50 volatile derivatives were identified from leaves, stem, latex and root extract. Enormous number of compounds isolated from ethanolic extact of leaves. In conclusion, E. agallocha has huge amount of polyphenols and terpenoids, which was reported to have endocrine, epidemic and endemic disease control as anti-microbial, anti-cancer and anti-diabetic agent.

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Excoecarins D, E, and K, from Excoecaria agallocha

Cited by 54 publications

References 12 publications

Three Diterpenoids (Excoecarins V1-V3) and a Flavanone Glycoside from the Fresh Stem of Excoecaria agallocha

Three Diterpenoids (Excoecarins V1-V3) and a Flavanone Glycoside from the Fresh Stem of Excoecaria agallocha

Beyerane Derivatives and a Sesquiterpene Dimer from Japanese Cypress (Chamaecyparis obtusa)

Insight on Excoecaria agallocha: An Overview

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