Megastigmane glycoside from Ludwigia Stolonifera
Abou El-Hamd1, H Mohamed1, Adila E Mohamed1, Abeer M Ismail1, Magdi A El-sayed2, Mohamed J Sheded2
1 Chemistry Department, Aswan-Faculty of Science, South Valley University, Aswan, Egypt
2 Botany Department, Aswan-Faculty of Science, South Valley University, Aswan, Egypt
|Date of Web Publication||8-Dec-2009|
Chemistry Department, Aswan-Faculty of Science, South Valley University, Aswan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Ludwigia genus belongs to family Onagraceae, is an edible medicinal plant and is also used as a vegetable by the local people in Southwestern China. Some species of this plant, has been used as a traditional treatment for edema, nephritis, and hypertension. Phytochemical study of the CH2 Cl2 : MeOH (1:1) extract of the aerial parts of Ludwigia stolonifera afforded a megastigmane glycoside named, roseoside. The structure was determined by comprehensive NMR studies including DEPT, COSY, HMQC, HMBC and MS.
Keywords: Ludwigia Stolonifera , megastigmane , glycoside , roseoside.
|How to cite this article:|
El-Hamd A, Mohamed H, Mohamed AE, Ismail AM, El-sayed MA, Sheded MJ. Megastigmane glycoside from Ludwigia Stolonifera. Phcog Mag 2009;5:306-8
|How to cite this URL:|
El-Hamd A, Mohamed H, Mohamed AE, Ismail AM, El-sayed MA, Sheded MJ. Megastigmane glycoside from Ludwigia Stolonifera. Phcog Mag [serial online] 2009 [cited 2021 May 15];5:306-8. Available from: http://www.phcog.com/text.asp?2009/5/20/306/58150
| Introduction|| |
Ludwigia , (family Onagraceae) from the tribe jussiaea, is an aquatic plant, which is a very variable genus that contains over 80 species grouped in 23 sections  . Species of this genus is an edible medicinal plant and is also used as a vegetable by the local people in southwestern china  . Some species of this plant, has been used as a traditional treatment for edema, nephritis, and hypertension  . Few reports have appeared in the literature on the chemistry and biological activity of this genus; thus previous studies have shown that the crude extract of Ludwigia octovalvis possess antidiabetic and immunosuppressive activities  . Many species of the genus have been investigated and found to contain oleanane-type triterpenes, triterpene acids and flavonoids. This paper describes the isolation, identification and structural elucidation of a megastigmane glycoside from the aerial parts of Ludwigia stolonifera .
| Materials and Methods|| |
NMR spectra were measured with a Bruker AMX-500 spectrometer, with TMS as an internal standard. CC: Silica gel (Merck, 60-120 mesh) and Sephadex LH-20 (Pharmacia). TLC and Preparative TLC: Silica gel 60 GF 254 (Merck). The compound was visualized either by spraying with vanillin reagent or under UV lamp.
Ludwigia stolonifera was collected in 2006 from Aswan, South of Egypt, Egypt. A voucher specimen of the collection was identified by Dr. Magdi A. El-Sayed and was deposited in the Department of Botany, Aswan Faculty of Science, Egypt.
Extraction and isolation
Air dried and powdered aerial parts (100 g) of Cleome arabica were extracted with CH2 Cl2 -methanol (1:1) at room temperature for 24 h. The extract was concentrated in vacuo to give a residue (14 g), which was chromatographed by using flash column chromatography on a silica gel eluted with n -hexane-CH2 Cl2 step-gradient and finally CH2Cl2- MeOH (85:15) (3 L each of the solvent). The CH2 Cl2 - methanol fraction (9.5:0.5) was carefully chromatographed on a Sephadex LH-20 column eluted with n -hexane- CH2 Cl2 -MeOH (7: 4: 0.5) with increasing the polarity to give a megastigmane glycoside, compound 1 (12 mg).
| Results and Discussion|| |
Compound 1 was obtained from the CH2 Cl2 -MeOH (9.5:0.5 %) fraction and appeared as a dark brown color on the TLC when treated with vanillin-sulphuric acid. Compound 1 , was isolated as a white powder, +20.3 ( c = 0.001, MeOH) and its IR spectrum showed absorption bands at 3250 cm -1 (OH groups) and a conjugated carbonyl group at 1650 cm -1 . The EI-MS of 1 gave a molecularion peak [M] + at m/z = 386 and exact mass determination at m/z = 386.1941 established the elemental composition as C19H30O8 (confirmed by 13 C NMR and DEPT analysis). The fragment ion at m/z = 368, due to the elimination of water molecule. The 1 H NMR spectrum showed a broad singlet at δ H 5.85 (brs, H-4), coupled with a carbon signal at δ C 127.8 (C-4) in HMQC spectrum. Additionally, it showed a broad singlet signal at δ H 5.84 integrated for two protons H-7 and H-8, two doublets at δ H 2.31 (H-2a), 2.14 (H-2b), coupled with a carbon signal at δ C 51.5, C-2 in HMQC spectrum. Furthermore, the 1 H NMR spectrum revealed the presence of four signals for the methyl groups at δ H 1.02 (s, H-11), 1.03 (s, H-12), 1.28 (d, J = 6.7, H-10), and 1.91 (d, J =1.4, H-13). The presence of the sugar moiety was suggested from the anomeric proton signal at δ H 4.33 ( d, J = 7.7, H-1`), which showed a correlation with the double of doublet at δ 3.16 (dd, J = 9.1, 7.7, H-2`) in 1 H -1 H COSY spectrum. The 13 CNMR spectrum of 1 indicated the presence of a glucose moiety and thirteen carbon atoms for the aglycone part. With the aid of DEPT and HMQC experiments, the carbons were classified as follows: one carbonyl carbon at δ 201.6 (C-3), four methyl carbons at [δ c 22.1 (C-10), 25.5 (C-11), 24.3 (C-12), 20.4 (C-13)], two methylene carbons at [ δ c 51.5 (C-2), 63.6 (C-6`)], nine methine carbons at [ δ C 127.8 (C-4), 132.1 (C-7), 135.8 (C-8), 78.0 (C-9), 103.4 (C-1`), 76.0 (C- 2`), 78.8 (C-3`),72.4 (C-4`), 78.2 (C-5`)], three quaternary carbons at [ δ C 43.2 (C-1), 167.8 (C-5), 80.7 (C-6)].
Confirmation of compound 1 was given by the HMBC analysis, the most important correlations were observed between; H-2 a ( δ 2.51, d) and C-1 ( δ 43.2), C-11 ( δ 25.5), C-12 ( δ 24.2); H-2 b ( δ 2.14, d) and C-3 ( δ 201.6), C-4 (δ 127.8), C-6 ( δ 80.7); H-4 (5.85, br s) and C-2 ( δ 51.5), C-13 ( δ 20.4); H-7 ( 5.84, br s ) and C-6 ( δ 80.7 ), C-8 ( δ 135.8), C-9 ( δ 78.0 ); H-8 (5.84, br s) and C-7 ( δ 132.1), C-9 (δ 78.0 ); H-10 (1.28, d) and C-9 ( δ 78.0), C-8 ( δ 135.8); H-11 (25.5, s) and C- 1 (δ 43.2), C-12 ( δ 24.2), C-6 ( δ 80.7), C-2 ( δ 51.5); H-12 (1.03, s) and C-11 ( δ 25.5), C-1( δ 43.2), C-6 ( δ 80.7), C-2 ( δ 51.5); H-13 (1.91, d) and C- 4 ( δ 127.8), C-5 ( δ 167.8), C-6 ( δ 80.7); H-1` (4.33, d) and C-1` ( δ 103.4), C-9 ( δ 78.0). On the basis of these results, compound 1 was identified as 4-hydroxy-3,5,5-trimethyl-4-[( E )-3-(3, 4, 5-trihydro-pyran-2-yloxy)-but-1-enyl]-cyclohex-2- enone (roseoside), isolated for the fi rst time from Ludwigia stolonifera .
| Acknowledgement|| |
The author thanks the late Prof. Ahmed A. Ahmed for his help and assistance. God bless him.[Table 1],[Figure 1],[Figure 2]
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[Figure 1], [Figure 2]