Antibacterial and Antioxidant Xanthones and Benzophenone from Garcinia smeathmannii

Abstract

A new prenylated xanthone, 1,3,5,8-tetrahydroxy-2-(3-methybut-2-enyl)-4-(3,7-dimethylocta-2,6-dienyl) xanthone (1), and a new benzophenone (2), together with four known xanthone derivatives, cheffouxanthone (3), smeathxanthone A (4), smeathxanthone B (5), ananixanthone (6), and two pentacyclic triterpenes, epi-friedelinol (7) and friedelin (8), were isolated from the stem bark of Garcinia smeathmannii. The structures of the compounds were elucidated on the basis of 1D and 2D NMR experiments, and compound 2 was further characterized and confirmed by single X-ray analysis. Compounds 1, 2, and 3 exhibited the most prominent Garcinia activity against gram-positive Enterococcus faecalis with minimal inhibitory concentration values of 8, 8, and 2 µg/mL, respectively, while compounds 1, 3, 4, and 6 showed the capacity to scavenge free radicals.

Two xanthones and two rotameric (3⟶8) biflavonoids from the Cameroonian medicinal plant Allanblackia floribunda Oliv. (Guttiferae)

“…Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. Although xanthones have been reported to have good antibacterial activity, 32 the two new isolated xanthones (1 and 2) did not display any inhibitory activity against the tested bacteria.…”

Two New Diphenylketones and a New Xanthone from Talaromyces islandicus EN-501, an Endophytic Fungus Derived from the Marine Red Alga Laurencia okamurai

“…The 13 C NMR spectrum (Figure S3) displayed 14 resonances, which were classified by DEPT (distortionless enhancement by polarization transfer, Figure S3) experiments as one methyl, five aromatic methines, and eight non-protonated (including one ketone and seven aromatic) carbons (Table 1). The 1 H and 13 C NMR spectroscopic data (Figures S2–S6) are evocative of a benzophenone scaffold [13]. In the HMBC spectrum (Figure S6), the correlations from the proton of 2′-OH (Δ H 11.42) to C-1′, C-2′, and C-3′ located the OH group at C-2′, while the correlations from H-7′ (Δ H 2.18) to C-2′, C-3′, and C-4′ placed the methyl group at C-3′, and at last, the correlations from the OH proton at Δ H 9.02 to C-4′, C-5′, and C-6′ determined this OH group at C-5′.…”

Chemical compounds and antibacterial activity of Garcinia dulcis (Roxb)kurz.

“…[31][32][33] The xanthone compounds are also known to have many biological activities, such as antioxidants, antimicrobials, anti-inflammatory, anti-cancer and antihyperlipid. [34][35][36][37] In this review, there are 46 types of xanthone compounds which have been reported to have been isolated from the plant and more than half of them are prenylated xanthones. This is in accordance with a previous study which stated that the primary type of xanthone compounds in the Guttiferae family (G. dulcis) is prenylated xanthones.…”