Lanostane-Type Triterpenoids from Diospyros discolor

Abstract

Plants in the Diospyros genus (Ebenacea) are well documented as a rich sources of naphthoquinones and triterpenes, which have been found to exhibit ichthyotoxic, 1,2) antimicrobial, [2][3][4] and antitumor activities. 4,5) Thirteen species of this genus are indigenous to Taiwan. Several species, including fruits of D. discolor WILLD., 6) leaves of D. kaki THUNB., 7) barks and stems of D. eriantha CHAMP., 8,9) stems of D. morrisiana HANCE., [10][11][12] fruits of D. ferrea, 13) and bark, root, fruits, leaves, and twigs of D. maritima BLUME. [1][2][3][4][5][14][15][16][17][18][19][20][21][22] have been studied for their chemical constituents, resulting in the isolation and structure elucidation of various triterpenes, lignans, steroids, benzoquinones, and naphthoquinone. Previously, we had reported on the isolation of some new naphthoquinones 15,16) and triterpenes from stems of D. maritima.5,17-21) As a part of our continuing interest in secondary metabolites from the Diospyros plants, we investigated the chemical principles of the twigs of D. discolor and isolated four new lanostane-type triterpenes: 24-ethyl-3b-methoxylanost-9(11)-en-25-ol (1), 3b-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3b -methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3b-methoxy-24-methyllanosta-9(11),25-dien-24-ol (4); in addition to three known triterpenes, betulinaldehyde, 23) betulinic acid methyl ester, 24) and ursaldehyde. 25) In this paper, we report the extraction, isolation, purification, and structural elucidation of four new lanostane-type triterpenes on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments.Compound 1 . In addition, the major fragment ions at m/z 255, 241 and 229 supported that the double bond located at C-9 and C-11. 27) From the above evidences, compound 1 was considered as lanosta-9(11)-ene triterpene with a C 10 H 21 O side chain. Detailed comparison of the 1 H-and 13 C-NMR data of 1 with those of the known lanostane-type triterpene, 25,26,27-trinor-3b -methoxylanost-9(11)-en-24-oic acid, isolated from the stem bark of Pinus luchuensis, 28) shows that the signals of the tetracyclic part were very similar to each other, except for the signals of C-20-C-27, C-31, and C-32 in the side chain part. Four new lanostane-type triterpenes, 24-ethyl-3b b-methoxylanost-9(11)-en-25-ol (1), 3b b-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3b b-methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3b b-methoxy-24-methyllanosta-9(11),25-dien-24-ol (4) together with three known triterpenes, betulinaldehyde, betulinic acid methyl ester, and ursaldehyde have been isolated from the methanol extract of the twigs of Diospyros discolor. The structures of those new compounds were elucidated by spectroscopic methods.

Anti-Adipogenic Activity of Secondary Metabolites Isolated from Smilax sieboldii Miq. on 3T3-L1 Adipocytes

“…Its molecular formula was determined to be C 32 H 54 O from the molecular ion at m/z 455.4275 [M + H] + based on HR-ESIMS, indicating six indices of hydrogen deficiency. The IR spectrum showed absorption bands at hydroxyl (3382 cm −1 ) and terminal double bond (3043, 1371, and 890 cm −1 ) functionalities [29]. The 1 H-NMR spectrum of 17 (Table 2) indicated the presence of eight tertiary methyls [δ H 1.03, 0.97, 0.80, 0.73, 0.64 (3H each, s), and 1.04 (3H × 3, s)], one secondary methyl [δ H 0.90 (3H, d, J = 6.…”

“…This was supported by the singlet signal of three chemically equivalent methyl groups [δ H 1.04 (3H × 3, s, H-26, H-27, H-32)] observed in the 1 H-NMR spectrum of 17, which revealed the HMBC correlations with C-24 (δ C 159.2) and ROESY correlations with H-31 (δ H 4.82), elucidating the structure of the side chain as CH(CH 3 )CH 2 CH 2 C(CH 2 )C(CH 3 ) 3 (Figure 4). The relative configuration for 17 was determined as follows: first, the large coupling constant of H-3 (J 2-3 = 11.2, 4.2 Hz) indicated that the hydroxyl group (3-OH) was oriented equatorially (β-position) at C-3 [29,31]. Next, the ROESY correlations between H-18 (δ H 0.64) and H-20 (δ H 1.39); and H-17 (δ H 1.61) and H-21 (δ H 0.90) were determined as R configuration for the stereochemistry of C-20.…”

Morphological and organoleptic fruit properties of various persimmon species (Diospyros spp.)

“…Názorne to dokumentuje aj obrázok 6. Pri ebenovníkoch je však všeobecne známe, že plody sa môžu vytvárať partenokarpicky ako bezsemenné, t.j. bez opelenia (Chandler, 1965), čo sme určili aj pri hodnotení plodov pri všetkých druhoch. Pre konzumentov sú takéto plody veľmi vhodné.…”

Composition, in vitro Cytotoxic, and Antimicrobial Activities of the Flower Essential Oil of Diospyros discolor from Taiwan

“…The wood is esteemed as a rare and precious material [2], but nevertheless, there are very few reports on the chemical composition of the species. Santosh and Sandhya [3,4] isolated anthraquinones from the bark of the tree; Ganapaty et al [5] reported dimeric naphthoquinones from the roots; Lee et al [6] found that the leaf extract had excellent antioxidant activity; and Chen et al [7] isolated a lanostane-type triterpenoid. As for essential oils, Smith and Luz [8] analyzed the composition of that from the fruit.…”