Flavanoids fromthe Stembark of Chisocheton pentandrus ( Meliaceae )

Two flavanoid compounds, catechin (1) and epicatechin (2), have been isolated from the stembark of Chisocheton pentandrus. The chemical structure of compounds1and2were identified by spectroscopic data including, UV, IR, NMR ( 1 H, 13 C, DEPT 135°, HMQC, HMBC, 1 H1 H COSY) and MS and by comparing with previously reported spectral data. Compounds 1 and 2, were isolated in this plant for first time and showed no cytotoxic activity against MCF-7 breast cancer cells.


INTRODUCTION
The tropical plant of Chisocheton belong to Meliaceae family is a higher plant that can grow up to 25m in height (Mabberly and Pannell, 1989).This plant is widespread in the tropical and subtropical countries including Indo-China, Papua New Guinea, Southern China, Thailand, Malaysia, Nepal, India, Bhutan and Myanmar (Vossen and Umali, 2002).Some of these plant species have been traditionally used as laxatives, medicinal and cosmetic ingredients as well as for toxins in fish (Lim, 2008).Chisocheton species were known to produce bioactive compounds with complex molecular structures such as erythrocarpine E and chisomecine A (Awang et al., 2007, Najmuldeen et al., 2011).Plant from this genus have been known to be a rich source of secondary metabolites including various sterols, terpenoids and alkaloids with biologically properties such as antifungal, antibacterial, antiviral, anti-inflammatory, and antiplasmodial agents (Mohamad et al., 2009, Joshi et al., 1987, Agbedahunsi et al., 2004).During the course of our continuing search for novel secondary metabolites from Indonesia Chisocheton plants, we isolated and described a new limonoid, dysobinol, from the bark of C. macrophyllus (Nurlelasari et al., 2017) and a new lanostane-type triterpenoid, 3β-hydroxy-25-ethyl-lanost-9(11),24(24′)diene, from the stembark of A. cumingianus (Katja et al., 2016).In the further search for novel compounds from Indonesia Chisocheton plants, recently we explore the phytochemistry of the stembark ofC.pentandrus.The plantis a higher plant and mainly distributed in nothern part of Sulawesi in Indonesia (Inada et al., 1997;Mabberley et al., 1995).Its stembark has been used as an Indonesian folk medicine for reducing fever, moisturizing the lungs, and for treating contused wound (Heyne., 1982).Although secondary metabolite compounds of other Chisocheton plants have been investigated previously, the chemical constituents of C. pentandrus is yet to be reported.In this paper, we describe the isolation and structural elucidation of two flavanoids, 1 and 2.

General Experimental Procedure
Melting points were measured on an electrothermal melting point apparatus and are uncorrected.UV spectra were measured by using a TECAN Infinite M200 pro, with MeOH.The IR spectra were recorded on a SHIMADZU IR Prestige-21 in KBr.The mass spectra were recorded with a Waters Xevo QTOF MS.NMR data were recorded on a Bruker Topspin spectrometer at 500 MHz for 1 H and 125 MHz for 13 C using TMS as an internal standard.Column chromatography was conducted on silica gel 60.TLC plates were precoated with silica gel GF 254 (Merck, 0.25 mm) and detection was achieved by spraying with 10% H 2 SO 4 in EtOH, followed by heating and under UV light at wavelength at 254 and 367 nm.

Plant Material
The stem bark of C. pentandrus was collected in Bogor Botanical Garden, Bogor, West Java Province, Indonesia in June 2016.The plant was identified by the staff of the Bogoriense Herbarium, Bogor, Indonesia and a voucher specimen (No.Bo-104) was deposited at the herbarium.

RESULT AND DISCUSSION
The methanol extract from the dried bark of C. pentandrus was concentrated and extracted successively with n-hexane, ethyl acetate and n-butanol The ethyl acetate extracts showed rich of flavonoid compound by detecting under uv light and AlCl 3 reagent.By using flavonoid test to guide separations, the ethyl acetate fraction was separated by combination of column chromatography on silica gelG60 and preparative TLC on silica gel GF 254 to afford two flavanoid compounds 1 and 2.
This flavonoid compounds, catechin (1) and epicatechin (2), was isolated in this plant for the first time and support also the occurence of flavonoid compound in Chisocheton genus besides the limonoid as a chemical marker.

CONCLUSIONS
Two known flavanoid compounds catechin (1) and epicatechin (2) have been isolated from the stembark of Chisocheton pentandrus.This compound was isolated from this plant for the first time.

Table 1 .
NMR data (500 MHz for 1 H and 125 MHz for 13 C, in DMSO-d 6 ) for 1 and 2