New Phenolic Principles from Hypericum sampsonii

Abstract

The phytochemistry and antidepressant activity of Hypericum perforatum (St. John's wort) have attracted much attention to the Hypericum genus and several biologically active components have been isolated. [1][2][3][4][5][6][7][8] Hypericum sampsonii (Guttiferae) is a herbal medicine used in the treatment of blood stasis, to relieve swelling, and as an antitumor herb in Taiwan. 9) Xanthones 10) and series of polyprenylated benzophenone derivatives [11][12][13][14][15] were previously isolated from this plant. In a continuation of our search for active components similar to H. perforatum in H. sampsonii, 15) We report here the isolation and structural determination of five new phenolic compounds together with 16 known compounds from the whole herbs of H. sampsonii. Results and DiscussionThe ethanolic extract of the whole herbs was successively partitioned with ethyl acetate and n-butanol. The ethyl acetate and BuOH-soluble fractions were chromatographed on silica gel and Sephadex LH-20 to give two new benzophenones, 2,6-dihydroxy-4-[(E)-5-hydroxy-3,7-dimethylocta-2,7-dienyloxy]benzophenone (1) and 2,6-dihydroxy-4-[(E)-7-hydroxy-3,7-dimethylocta-2-enyloxy]benzophenone (2), a new xanthone, hyperxanthone (3), a new bisanthraquinone glycoside, R-(Ϫ) -skyrin-6-O-b-D-xylopyranoside (4), and 2-caffeoyloxy-3-hydroxy-3-(3,4-dihydroxyphenyl)propyl alcohol (5) Using the anti-hepatitis B virus (HBV)-producing cell line MS-G2 in vitro cultural system-guided screening was performed, and two new benzophenones, 2,6-dihydroxy-4-[(E)-5-hydroxy-3,7-dimethylocta-2,7-dienyloxy]benzophenone (1) and 2,6-dihydroxy-4-[(E)-7-hydroxy-3,7-dimethylocta-2-enyloxy]benzophenone (2), a new xanthone, hyperxanthone (3), a new bisanthraquinone glycoside, R-(؊)-skyrin-6-O-b b-D-xylopyranoside (4), and 2-caffeoyloxy-3-hydroxy-3-(3,4-dihydroxyphenyl)propyl alcohol (5), and 16 known compounds were isolated from the anti-HBV active fraction of the whole herbs of Hypericum sampsonii. Their structures were elucidated using spectroscopic methods, mainly 2D NMR and MS spectrometry. Circular dichroism was used to determine the stereochemistry of bisanthraquinone glycosides.

Naturally Occurring Xanthones: Chemistry and Biology

“…Among these, only two natural sulfonated xanthones, namely, 1,3-dihydroxy-5-methoxyxanthone-4-sulfonate and 5-O--D-glucopyranosyl-1,3-dihydroxyxanthone-4-sulfonate, are reported from Hypericum sampsonii. These sulfonated xanthones were found to exhibit significant cytotoxicity against cancer cell line [15,16]. 1,3,5-, 1,5,6-, 1,6,7-, and 2,3,4-trihydroxyxanthone, seventeen methyl ethers, and two methylenedioxy derivatives from nine genera have been reported.…”

Naturally-Occurring Xanthones: Recent Developments

“…Meanwhile, an increasing number of bioactive xanthones has been isolated by bioassay-guided fractionation methods. Among the biological activities used to monitor the isolation of bioactive xanthones are antibacterial [15], antifungal [16], antiviral [17,18] trypanocidal [19,20] activities and cytotoxicity against human carcinoma cell lines [21][22][23][24]. Some specific activities such as potentiation of nerve growth factor (NGF) action in the PC12D cell [25] and secreted aspartic protease (SAP) of Candida albicans [26] have also been used to monitor the isolation of several bioactive prenylated xanthones.…”

“…However, only xanthones (17) isolated from the stems of Drypetes littoralis (Euphorbiaceae) [57], and carboxyxanthones (19) and (20) from a microfungus Xylaria sp. [58] as well as (23) were reported as new natural products.…”

Two New Xanthones from Hypericum sampsonii and biological activity of the isolated compounds

“…In mainland China, H. sampsonii is used in the treatment of numerous disorders such as backache, burns, diarrhoea, snakebites and swellings (Liang, 1998). Because of its various bioactivities, H. sampsonii has been investigated and some xanthones and polyprenylated benzophenone derivatives have been isolated (Hu and Sim, 1998, 1999a, 1999b, 2000Xiao et al, 2007Xiao et al, , 2008Chen and Chen, 1985;Hong et al, 2004;Guo et al, 2005;Don et al, 2004). As a part of a programme to discover new antibacterial natural products from plant resources, a CH2Cl2 extract of the aerial parts of H. sampsonii was shown to exhibit significant biological activity in a preliminary in vitro screening against MRSA with an MIC of 64 mg/mL.…”