Ardisiphenols A-C, Novel Antioxidants from the Fruits of Ardisia colorata.

Abstract

Novel alk(en)ylphenols, named ardisiphenols A-C (1-3) were isolated from the fruits of Ardisia colorata, together with known alk(en)ylresorcinols (4-6). Their structures were determined by the NMR and MS/MS analyses. All compounds showed scavenging activities towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and cytotoxicities against murine breast cancer cell line, FM3A.Key words Ardisia colorata; Myrsinaceae; ardisiphenol; alk(en)ylphenol; cytotoxicity Ardisia colorata ROXB. (Myrsinaceae) is used as a folk medicine for liver disease, cough and diarrhoea in Thailand. A previous phytochemical investigation on this species resulted in the isolation of rapanone and ilexol.1) No further detailed study has been reported. In the course of the screening for antioxidants in Thai medicinal plants, A. colorata showed a scavenging activity towards DPPH radical in TLC autographic assay.2) This paper deals with the structure elucidation of the newly isolated alk(en)ylphenols and known alk(en)ylresorcinols, and their cytotoxicities against murine breast cancer cell line, FM3A.The 75% ethanol extract of the dried fruits of A. colorata (500 g) was partitioned by successive extraction with organic solvents of increasing polarity. Initially the attention was paid to the antioxidative compounds in n-hexane fraction, then repeated silica gel chromatographies (CHCl 3 -MeOH, n-hexaneAcOEt) and HPLC (MeOH-0.2% AcOH, 85 : 15) were performed to give new compounds 1-3 (0.043, 0.084, 0.058%, respectively) and known compounds 4-6 (0.022, 0.053, 0.037%, respectively). The six compounds were all positive for ferric chloride test and showed scavenging activities towards DPPH radical in TLC autographic assay.Ardisiphenol A (1) has a molecular formula C 23 H 38 O 4 from high-resolution (HR)-FAB-MS. The 1 H-NMR spectrum of 1 showed signals of two meta coupled aromatic protons at d 6.13 (d, Jϭ2.7 Hz, H-5) and 6.21 (d, Jϭ2.7 Hz, H-3), and signals due to a long alkyl side chain at d 0.89 (3H, t, Jϭ7.0 Hz, H-15Ј), 1.28 (24H, overlapped, H-3Ј--14Ј), 1.50 (homobenzyl 2H, m) and 2.35 (benzyl 2H, t, Jϭ7.3 Hz). The 13 C-NMR spectrum of 1 showed signals for tetra-substituted benzene at d 131. 6, 150.6, 102.4, 156.5, 107.9 and 137.4, and signals for an alkyl side chain which were assigned as shown in Fig. 1 by two-dimensional (2D)-NMR spectra. Signals of acetoxyl group were also observed at d 2.25 (3H, s), 20.5 (OCOCH 3 ) and 171.6 (OCOCH 3 ). Electron impact (EI)-MS showed a base peak at m/z 139 corresponding to a benzylic fragmentation of deacetylated ion of 1 and an intense peak of deacetylated ion of 1 at 335 (MϪAc) ϩ . Therefore, it was suspected that 1 was a benzene derivative tetra-substituted by two hydroxyl groups, an acetoxyl group and an unbranched C 15 alkyl chain. However, the position of the acetoxyl group was not deduced from above experimental data and the nuclear Overhauser effect (NOE) enhancement was not observed between the acetyl group and any other protons. To locate hydroxyl groups on the benzene ring, the 13 C-NMR of 1 was caref...

Ardisiphenols and Other Antioxidant Principles from the Fruits of Ardisia colorata.

“…They were fractionated by repeated column chromatographies (CC) according to the activity in the TLC autographic assay. 5) n-Hexane-soluble fraction yielded ardisiphenols (1-3) and alkylresorcinols (4)(5)(6), as previously reported.…”

“…The position of the phenolic hydroxyl groups for 1 and 2 was deduced from the analysis of the heteronuclear multiple bond connectivity (HMBC) spectrum of 2 which was measured in dimethylsulfoxide (DMSO)-d 6 (Fig. 2).…”

Antiproliferative and antimicrobial activities of alkylbenzoquinone derivatives fromArdisia kivuensis

“…Considering these criteria, the activity obtained with our compounds against THP-1 could be considered as significant. The occurrence of alkylbenzoquinone in Ardisia species as well as their cytotoxic activity against murine breast cancer cell line was previously reported (Sumino et al, 2001). Apart THP-1 cell, the antiproliferative activity of compounds against the other cell lines was ranged from moderated to weak.…”

Evaluation of Phytochemical Screening and Antimicrobial Activities of Ethanolic Extracts of Leaves and Bark of Ardisia Colorata

“…is a tree or shrub from Myrsinaceae family. It is used as folk medicine for liver disease, cough and diarrhea in Thailand [4]. The leaves are alternate or pseudo-verticillate, usually punctate or punctate-lineate.…”