Benzophenone glycosides from Hypericum humifusum ssp. austral

Two New Benzophenones From the Endohydric Moss Polytrichastrum formosum

Two new benzophenone derivatives (1 and 2), were obtained from the endohydric moss Polytrichastrum formosum. Their structures were established by 1D and 2D NMR spectroscopic and HRESIMS methods. The cytotoxicity of 1 and 2 against HCT-116, A-549, HepG2 and HeLa cell lines was evaluated, but no obvious cytotoxic activities were observed (IC50 >100 µM). Benzophenones may be characteristic components of Polytrichaceae.

Two new benzophenones from endohydric moss Polytrichum Commune

Two new benzophenones (1 and 2), were isolated from the endohydric moss Polytrichum commune. Their structures were elucidated by spectroscopic methods including extensive 2 D NMR techniques. Compound 2 is the first example of benzophenone with a rare cyclopropylacetamide from the natural resources. Compounds 1 and 2 were screened their cytotoxicity against five cancer cell lines (HCT-116, A-549, MCF-7, HepG2, A-375,), and no cytotoxic activities were observed (IC₅₀ > 100 μM).

Polycyclic Polyprenylated Acylphloroglucinol Derivatives from Hypericum acmosepalum

Hypericum acmosepalum belongs to the Hypericum genus of the Guttiferae family. The characteristic components in Hypericum are mainly a series of polycyclic polyprenylated acylphloroglucinols (PPAPs), flavonoids, and xanthones. Among them, the PPAPs have received much attention due to their novel structures and diverse pharmacological activities and have become hot spots in organic chemistry and medicinal chemistry. However, there are few reports about the chemical constituents of Hypericum acmosepalum at present, especially the PPAPs. This research is dedicated to the study of the air-dried aerial parts of Hypericum acmosepalum, which were extracted with 95% EtOH under reflux, then suspended and successively partitioned with petroleum ether and ethyl acetate. Five PPAP derivatives were obtained using various chromatographic techniques, and their structures were determined by NMR spectroscopic data, including two new phloroglucinol derivatives, hyperacmosin A (1) and hyperacmosin B (2). Those compounds were evaluated for their neuroprotective effect using two models.

Structural diversity and biological activities of phloroglucinol derivatives from Hypericum species

Plants of the genus Hypericum (Hypericaceae) are used in folk medicine all over the world, H. perforatum being the most well-known species. Standardized extracts of this plant are commercially-available to treat mild to moderate depression cases. The present review summarizes the literature published up to 2016 concerning the phloroglucinol derivatives isolated from Hypericum species, together with their structural features and biological activities. These phytochemical studies led to the isolation of 101 prenylated phloroglucinols, chromanes and chromenes, 35 dimeric acylphloroglucinols, 235 polycyclic polyprenylated acylphloroglucinols, 25 simple benzophenones and 33 phloroglucinol-terpene adducts. These compounds show a diverse range of biological activities, such as antimicrobial, cytotoxic, antinociceptive and antidepressant-like effects.

Phenolic metabolites from Hypericum kelleri Bald., an endemic species of Crete (Greece)

Thirteen compounds were isolated from the aerial parts of Hypericum kelleri Bald., growing as an endemic on the island of Crete (Greece). These compounds comprise four previously unknown prenylated xanthones 1,2-dihydro-3,8-dihydroxy-6-methoxy-1,1,5-tri(3-methylbut-2-enyl)xanthen-2,9-dione (kellerine A), 1,2-dihydro-3,6,8-trihydroxy-1,1,5-tri(3-methylbut-2-enyl)xanthen-2,9-dione (kellerine B), 1,2-dihydro-3,8-dihydroxy-6-methoxy-1,1-bi(3-methylbut-2-enyl)xanthen-2,9-dione (6-methylpatulone), (R/S)-1,3,5-trihydroxy-2-(3-methyl-2-buten-1-yl)-4-[2-(3-methylbut-2-enyl)-3-methylbut-3-enyl]-6-methoxy-9H-xanthen-9-one ((2″R/S)-kellerine C) and the hitherto undescribed depsidone (R/S)-1,3,6-trihydroxy-5-methoxy-2-(3-methyl-2-buten-1-yl)-4-[2-(3-methylbut-2-enyl)-3-methylbut-3-enyl]-11Η-dibenzo[b,e] [1,4]dioxepin-9-one ((2″R/S)-creticine). As known compounds, brevipsidone D, 4-geranyl-2-(2'-isobutyryl)-phloroglucinol, 4-geranyl-2-(2'-methylbutyryl)-phloroglucinol, I3, II8-biapigenin, quercetin, avicularin, pseudohypericin and neochlorogenic acid have been isolated. The structures were elucidated on the basis of their 1D, 2D NMR, CD and MS data. The study confirms the typical occurrence of xanthones in Hypericum section Oligostema (Boiss.) Stef., and is also the first report on the simultaneous isolation of acylphloroglucinols in this section. Furthermore the first evidence of depsidones in the genus Hypericum L. is reported. Cytotoxicity was investigated in HeLa cells for prenylated xanthones and the depsidones. Both triprenylated 1,2-dihydroxanthones (kellerine A and B) showed significant in vitro cytotoxicity with IC₅₀ values of 2.5 ± 0.1 (kellerine A) and 5.9 ± 0.9 (kellerine B) μM, whereas other compounds were less cytotoxic (IC₅₀ > 20 μM).

Bioactive polycyclic polyprenylated acylphloroglucinols from Hypericum perforatum

Fifteen new polycyclic polyprenylated acylphloroglucinols with dual-targeted inhibitory activities for Alzheimer's disease, were isolated from Hypericum perforatum.

Tricyclic Polyprenylated Acylphloroglucinols from St John's Wort, Hypericum perforatum

The new polyprenylated acylphloroglucinol derivatives 1-15 and the known furohyperforin (16) were isolated from the stems and leaves of Hypericum perforatum. Their structures were determined by analyses of NMR and HRESIMS data. Their absolute configurations were elucidated by a combination of electronic circular dichroism (ECD) and Rh₂(OCOCF₃)₄-induced ECD, as well as X-ray diffraction crystallography. The new hyperforatin F (9) contains a unique acetyl functionality at C-1 of the bicyclo[3.3.1]nonane core. Hyperforatins G (10) and H (11) are similarly the first examples of naturally occurring [3.3.1]-type polycyclic prenylated acylphloroglucinols possessing a carbonyl functionality at C-32. The compounds were tested for their acetylcholinesterase (AChE) inhibitory activities and cytotoxic activities against a panel of human tumor cell lines. Compounds 3, 5, 6, 8, and 9 exerted moderate inhibitory activities (IC₅₀ 3.98-9.13 μM) against AChE.

Flavonoids as chemotaxonomic markers in the genus Drosera

The botanical classification of the huge genus Drosera remains controversial since long. In the present study, the pattern of major phenolic compounds in ten Drosera species belonging to seven different subgenera and/or sections of the genus was investigated for chemotaxonomic allocation. The composition of flavonoids and ellagic acid derivatives in Drosera adelae, Drosera burmannii, Drosera dielsiana, Drosera hilaris, Drosera montana, Drosera petiolaris, and Drosera pygmaea was elucidated for the first time. The scarce data on these compounds in Drosera binata, Drosera aliciae, and Drosera spatulata were complemented significantly. Detailed LC-DAD-MS, LC-NMR, and offline 1D and 2D NMR analyses resulted in the unambiguous identification of around 40 different substances, three of them (8-hydroxy-luteolin-8-O-arabinopyranoside, tricetin-7-O-xylopyranoside and 8-hydroxytricetin-8-O-arabinopyranoside) being natural products described for the first time. The distribution of the compounds characterized underlines their potential to serve as chemotaxonomic markers in this genus.

Structural diversity and bioactivities of natural benzophenones

Natural benzophenones are a class of compounds with more than 300 members, mainly in the Clusiaceae family. We review key benzophenones, and provide an in-depth discussion of their great structural diversity and biological activity.