New steroidal glycosides from the stem bark of Mimusops elengi

Abstract

Two new steroidal glycosides (1 and 2) have been isolated from the ethanolic extract of the stem bark of Mimusops elengi L. and characterized as Keywords: Mimusops elengi L., Sapotaceae, stem bark, steroidal glycosides.Mimusops elengi L. (Sapotaceae) is an ornamental small tree with sweet scented flowers growing wild throughout the greater part of India [1]. All parts of the plant are prescribed in the indigenous system of medicine as a febrifuge, astringent, purgative, and stimulant [2]. The decoction of the bark is used as a gargle [3]. It exhibited antimicrobial, antiulcer, hypotensive, anti-HIV, and spasmolytic activities [4][5][6][7][8]. Ursolic acid, betulinic acid, the fatty acid ester of D-spinasterol [9], 3E,6E,19D,23-tetrahydroxyurs-12-ene, 1E-hydroxy-3E-hexanoyllup-20(29)-ene-23,28-dioic acid, and bassic acid have been isolated from the bark [10,11]. This paper deals with the isolation and structural elucidation of two new steroidal glycosides from the stem bark of Mimusops elengi L.Compound 1, designated as stigmasterol-E-D-glycopyranoside, was obtained as a colorless amorphous powder from chloroform-methanol (19:1) eluants. It gave a positive test for sterol glycosides. Its IR spectrum exhibited absorption bands for hydroxyl groups (3450, 3380, 3260 cm -1 ), ester group (1738 cm -1 ), and unsaturation (1614 cm -1 ). On the basis of mass and 13 C NMR spectra, its molecular weight was established at m/z 750, consistent with the molecular formula of a sterol diglucoside, C 41 H 66 O 12 , and confirmed by HR-MS 751.9713 [M + H] + . Its mass spectrum showed important ion fragments appearing at m/z 411 [M -C 12 H 19 O 11 , diglycoside] + , 271 [411 -C 10 H 19 , side chain] + , 255 [271 -Me] + , and 239 [255 -Me] + .These fragments suggested that it was a C 29 sterol possessing one double bond in the carbocyclic ring system and one double bond in the side chain. The mass spectrum indicated the presence of an ethyl group in the side chain, which was placed at C-24 on the basis of biosynthesis analogy as well as similarities in chemical shifts of protons and carbons of the side chain with the related compounds. The ion fragments at m/z 339 [M -411] + and 179 [C 6 H 11 O 6 ] + suggested the glucuronosyl glucoside nature of the carbohydrate moiety. The 1 H NMR spectrum of 1 exhibited two one-proton multiplets at G 5.07 and 5.28 assigned to vinylic H-22 and H-23. A one-proton broad signal at G 5.30 was ascribed to vinylic H-6. A one-proton broad multiplet at G 3.85 with half-width 16.5 Hz was attributed to D-oriented C-3 carbinol proton. Two one-proton doublets at G 4.95 (J = 7.2 Hz) and 4.88 (J = 7.0 Hz) were attributed to H-1c and H-1cc anomeric protons, respectively. A two-proton broad signal at G 3.33 was associated with oxygenated C-6cc methylene protons. The remaining hydroxymethine protons of the glycosidic linkage appeared between G 4.50-3.35. Two three-proton broad signals at G 0.66 and 1.19 were assigned to C-18 and C-19 tertiary methyl protons. Four doublets at G 0.96 (J = 6.1 Hz), 0.86 (J = 8.4 Hz), ...

New phytoconstituents from the aerial parts of Fumaria parviflora Lam

“…The 1 H NMR and 13 C NMR spectral data of 4 were compared with the reported data of steroid. [ 14 15 16 ] On the basis of above evidences the structure of 4 has been established as 4-oxo-stigmast-5-en-3β-ol- D -glucopyranoside. This is a new steroidal glycoside.…”

Characterization and Quantitation of Steryl Glycosides in Solanum melongena

“…Acid hydrolysis of SGs was performed as described in the literature in 2 mL of 1 M methanolic hydrochloric acid for 3 h at 70 °C . After the addition of 1 mL of water, free sterols were extracted with n -hexane (2 × 2 mL) and dried with argon.…”

“…Acid hydrolysis of SGs was performed as described in the literature in 2 mL of 1 M methanolic hydrochloric acid for 3 h at 70 °C. 27 After the addition of 1 mL of water, free sterols were extracted with n-hexane (2 × 2 mL) and dried with argon. Residues were dissolved in pyridine (50 μL), and N,Obis(trimethylsilyl)-acetamide with 5% trimethylchlorosilane (50 μL) was added.…”

Evaluation of Biological Activities of Extracts and Chemical Constituents of <i>Mimusops elengi</i>

“…elengi is known to possess various phytochemicals such as gallic acid esters, flavones, triterpenoids and steroids [2,[4][5]. The volatile constituents of the flowers have also been reported [6].…”

“…Previous studies on M. elengi were mainly focused on the isolation and characterization of its phytochemical constituents, mostly from the stem bark, fruit, seeds and roots [10]. Moreover, most of the biological activities reported for M. elengi were on the extracts rather than the active constituents which might be responsible for its observed activities [1,9].…”