CONTRIBUTION TO THE STUDY ON CHEMICAL CONSTITUENTS OF HYDROCOTYLE VULGARIS ( L . ) , APIACEAE

The essential oil of Hydrocotyle vulgaris was analyzed by GC-MS then tested citotoxicity on the cancer cells. The result showed that the essential oil of Hydrocotyle vulgaris had weaker bioactities than the one of Hydrocotyle bonariensis, and in two species had the same main compounds. In addition, from the ethyl acetate extract, quercetin 3-Ogalactopyranoside was isolated and identified by the spectrum data 1D, 2D-NMR and MS. Key works: Hydrocotyle vulgaris, quercetin 3-O-galactopyranoside, bioactivities on RD, Hep-G2 and LU cancer cells.


INTRODUCTION
Hydrocotyle vulgaris (marsh pennywort, water pennywort, Rau ma la sen) is a new plant growing in the Mekong-delta and used with H. asiatica, H. sibthorpioides as a jumble vegetable.Hydrocotyle and Centella species (Apiaceae) produce characteristic essential oils throughout the whole plant.It is known that H. sibthorpioides Lam and H. maritima Honda have hemostatic and antitumor activities [1] .Besides, H. vulgaris has the botanical aspect similar to the one of the species H. bonariensis.
In the continuation of the study on Hydrocotyle genus, now we report the chemical constituents of H. vulgaris and their bioactivities in vitro on RD and Hep-G2, LU cancer cells.These compounds of essential oil and quercetin 3-O-galactopyranoside were identified by the spectrum data NMR, MS or GC-MS.

RESULT AND DISCUSSION
Compound (1) was isolated from the ethyl acetate extract and presented as yellow crystals.Its TLC, showed indigo-blue spot when the layer was sprayed by solution FeCl 3 5% in
Table 1. 13 C NMR δppm values in DMSOd 6 solutions Hydrcotyle vulgaris was divided into stem, leave and flower and each part was subjected to the steam distillation.Each essential oil was analyzed by GC-MS and the results were presented in table 2. The major components of essential oil of the stem and the flower are the same with the presence of some sesquiterpenes such as: santalene, β-farnesene, βsesquiphellandrene, β-bisabolene.On the contrary, the essential oil of leave contained alcohol and aldehyde such as 3-hexen-1-ol and 2-hexenal with the great amount, like the one of H. bonariensis.
The essential oil was evaluated the antimicrobial activity on E. coli, P. aeruginosa, S. aureus, F. oxysporum (table 3) and was also tested the cytotoxicity on the RD, Hep-G2, LU cancer cells by the Likhiwitayawuid assay (table 4).The essential oil of H. vulgaris had weaker bioactivities than the one of H. bonariensis.

General
1 H-and 13 C-NMR were recorded on Bruker Avance 500 MHz and 125 MHz, respectively, in MEOD.LC-MS spectra were carried out on Agilent-MSD-Trap-SL with the column of

Trang 32
Adserbphere UHF C18.All spectrums were recorded in the Institute of Chemistry, Vietnamese Academy of Science and Technology, Cau Giay Dist., Ha Noi.
The essential oil was evaluated the antimicrobial activities on E. coli, P. aeruginosa, S. aureus, F. oxysporum and cytotoxic activities on the RD, Hep-G2, LU by the Likhiwitayawuid assay.

Plant material
The leaves of Hydrocotyle vulgaris L. were collected in Tien Giang province in December 2007.A voucher specimen was determined by Mr. Phan Đuc Binh, Assistant editor of Journal Medicine and Health-Ho Chi Minh City and was deposited in Department of Sciences, Can Tho University.

Biotest
Whole raw plant of H. vulgaris was divided into stem, leave and flower and each part was subjected to the steam distillation.The essential oils are faint aroma light yellow oil, with small content (0,057 %), ( 30 d ): 0,737, ( 30 D n ): 1,571.Each essential oil was studied by GC-MS.Because of the lack of sample, the essential oil of different parts of the plant were mixed together and then was evaluated the antimicrobial activities and cytotoxic activities on the RD, Hep-G2, LU cancer cells.

Table 2 .
The essential oil of H. vulgaris

Table 3 .
Result of the antimicrobial assay of the essential oil.

Table 4 .
Result of the cytotoxicity test on cancer cells of the essential oil.