Bioassay-Guided Isolation of Prenylated Xanthone Derivatives from the Leaves of Garcinia oligantha

Abstract

Four new dihydroxanthone derivatives (1-4), four new tetrahydroxanthone derivatives (5-8), two new xanthone derivatives (9 and 10), and two known caged tetrahydroxanthones were isolated from extracts of the leaves of Garcinia oligantha by bioassay-guided fractionation. These structures of the new compounds were elucidated by NMR and MS spectroscopic data analysis, and the absolute configurations of compounds 1 and 5-7 were determined by electronic circular dichroism and/or single-crystal X-ray diffraction analysis. Compounds 6-9 were shown to be unusual xanthone derivatives with an isopropyl group, which was confirmed by the X-ray crystallographic structure of compound 8. The inhibitory activities of these isolates against four human tumor cell lines (A549, HepG2, HT-29, and PC-3) were assayed, and compounds 1, 2, 5, 11, and 12 showed inhibitory effects on tumor cell growth, with IC50 values ranging from 2.1 to 8.6 μM.

Cytotoxic Prenylated Xanthones from the Leaves of Garcinia bracteata

“…They include six new prenylated xanthones (1-6) (▶ Fig. 1) and sixteen known xanthones (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) (Fig. 54S, Supporting Information).…”

“…54S, Supporting Information). Compounds 7-23 were identified as allanxanthone A (7) [18], ananixanthone (8) [19], morusignin I (9) [20], gartanin (10) [21], 8-deoxygartanin (11) [22], 1,3,5-trihydroxy-6′,6′-dimethylpyrano(2′,3′: [22], brasixanthone B (14) [24], 3-hydroxyblancoxanthone (15) [25], xanthone V1 (16) [26], gerontoxanthone I (17) [27], assiguxanthone A (18) [28], 1,3,5-trihydroxy-13,13-dimethyl-2H-pyran [7,6-b]xanthen-9-one (19) [23], 1,3,5-trihydroxy-2prenylxanthone (20) [29], xanthone V1a (21) [26], latisxanthone D (22) [28], and norswetianin (23) [30] by comparison of their spectroscopic data with those reported in the literature.…”

“…Plants from this genus are well known as rich natural sources of xanthones, benzophenones, and biflavonoids, and these constituents show a wide range of biological and pharmacological properties [2][3][4][5][6]. During our continual efforts to identify anticancer agents from Garcinia plants native to China [7][8][9][10], we found that a 95 % EtOH extract of the leaves of Garcinia bracteata exhibited strong cytotoxic activity against ten human cancer cell lines [11]. G. bracteata C. Y. Wu ex Y. H. Li, a shrub 1-3 m tall, is mainly distributed in 200-1200 m dense forests in the Guangdong and Hainan provinces of China [1].…”

“…In this work, we investigated the xanthones present in the leaves of G. bracteata. Six previously undescribed prenylated xanthones (1)(2)(3)(4)(5)(6) and seventeen known xanthones (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) were isolated from an extract of the leaves of G. bracteata. Their structures were elucidated on the basis of spectroscopic methods and their inhibitory activities against HeLa, A549, PC-3, HT-29, and WPMY-1 cells were examined.…”

Xanthones and Cancer: from Natural Sources to Mechanisms of Action

“…Twigs no [121] Oliganthaxanthone A Garcinia oligantha Leaves yes [122] Oliganthaxanthone B Garcinia oligantha Leaves yes [122] Oliganthin A Garcinia oligantha Stems yes [123] Oliganthin B Garcinia oligantha Stems yes [123] Oliganthin C Garcinia oligantha Stems yes [123] Oliganthin D Garcinia oligantha Stems yes [123] Oliganthin E Garcinia oligantha Stems no [124] Oliganthin F Garcinia oligantha Stems no [124] Oliganthin G Garcinia oligantha Stems no [124] Oliganthin M Garcinia oligantha Leaves yes [125] Oliganthin N Garcinia oligantha Leaves no [125] Oliganthin O Garcinia oligantha Leaves yes [125] Oliganthin P Garcinia oligantha Leaves yes [125] Oliganthone A Garcinia oligantha Stems yes [126] Oxythorelione A Calophyllum thorelii Barks yes [127] Paucinervin E Garcinia paucinervis Leaves no [128] Paucinervin F Garcinia paucinervis Leaves no [128] Paucinervin G Garcinia paucinervis Leaves no [128] Paucinervin H Garcinia paucinervis Leaves yes [129] Paucinervin I Garcinia paucinervis Leaves yes [129] Paucinervin J Garcinia paucinervis Leaves yes [129] Pedunxanthone A Garcinia pedunculata…”