Antiproliferative polycyclic polyprenylated acylphloroglucinols from Garcinia paucinervis

Bioassay-guided isolation of the stems of Garcinia paucinervis led to one new adamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), (-)-garpauvinin A (1), and four known analogues (2-5). The structure and absolute configuration of 1 was established via spectroscopic techniques and ECD method. All the isolates displayed moderate antiproliferative activity against HL-60, PC-3 and Caco-2 human cancer cell lines with IC50 values ranging from 0.81 to 19.92 μM, and exhibited low toxicity on WPMY-1 normal human cells, showing selectivity between normal and malignant prostate cells. The biosynthetic pathways of the isolated PPAPs were proposed.

Structurally diverse polycyclic polyprenylated acylphloroglucinols with protective effect on human vein endothelial cells injured by high-glucose from Hypericum acmosepalum N. Robson

Hyperacmotone A, a polycyclic polyprenylated acylphloroglucinol (PPAP) with an unprecedented skeleton, along with five undescribed congeners and eleven reported ones, was isolated from Hypericum acmosepalum. Hyperacmotone A possesses a unique monocyclic ring skeleton based on a cyclopent-4-ene-1,3-dione acylphloroglucinol core. Their structures were elucidated by extensive analysis of HRESIMS, NMR, biogenetic pathway, and quantum-chemical calculations. In addition, hypercohone G exhibited significant protective effects on high-glucose-injured HUVECs.

Polycyclic polyprenylated acylphloroglucinols from Hypericum beanii and their hepatoprotective activity

Twenty-seven polycyclic polyprenylated acylphloroglucinols (PPAPs) with diverse skeletons, including seven previously undescribed ones (hyperbeanins A-G), were isolated from the aerial parts of Hypericum beanii. Their structures were established by comprehensive analysis of NMR, HRESIMS, and experimental electronic circular dichroism (ECD) spectra. Hyperbeanin A was a monocyclic polyprenylated acylphloroglucinols (MPAPs) with an unusual spiro-fused cyclopropane ring. Four of the isolated compounds showed obvious hepatoprotective activity against paracetamol-induced HepG2 cell damage at 10 μM. The present results suggested that these compounds would be potential hepatoprotective agents. In addition, the plausible biogenetic pathways of hyperbeanins A-G were proposed, which gave an insight for future biomimetic synthesis of them.

Four new polyprenylated acylphloroglucinol derivatives from Hypericum beanii

Two new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperbeanins P-Q (1-2), and two new biosynthetic precursors, hyperbeanins R-S (3-4), were isolated from Hypericum beanii, together with three known analogs (5-7). Compound 1 was one of type A PPAPs featured with unusual bicyclo[5.3.1]hendecane core. The structures of isolates were established by NMR spectroscopic methods, experimental electronic circular dichroism (ECD) spectra and comparisons with known compounds. Compounds 5 and 6 showed obvious hepatoprotective activity at 10 µM against paracetamol-induced HepG2 cell damage.

Hypericumsampsonii attenuates inflammation in mice with ulcerative colitis via regulation of PDE4/PKA/CREB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum sampsonii Hance (Yuanbaocao), a traditional herbal medicine with various pharmacological properties, is traditionally used to treat diarrhea and enteritis in China for hundreds of years. Investigations have uncovered its anti-inflammatory effects and corresponding bioactive constituents in H. sampsonii, however, the mechanisms of action for the treatment of enteritis are still unclear.

AIMS OF THE STUDY

This study aims to investigate the therapeutic effects and molecular mechanisms of H. sampsonii in a dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice model.

MATERIALS AND METHODS

The major ingredients of the ethyl acetate extract (HS) in H. sampsonii were analyzed by UPLC-QTOF-MS. The inflammatory state of UC mice was caused by 3% DSS once daily for seven days. During DSS treatment, the mice in the positive drug group and the other three groups were orally administered 5-ASA (positive control) or HS daily. After treatment with HS or 5-ASA for a week, colonic pathological observation and the molecular biological index were performed for therapeutic evaluation, including visual inspection in the length and weight of colons and spleens, pathological morphology by hematoxylin and eosin (HE) staining, determination of oxidative markers, inflammatory cytokines and tumor necrosis factor-alpha (TNF-α) levels in colonic tissues as well as spleen index. Gene expression levels of inflammatory cytokines, antioxidant enzymes and PDE4 were detected using kits and PCR, while the expression of colonic tight junction proteins and relative signals of PKA/CREB signaling pathway were analyzed by Western blot.

RESULTS

The main components in HS were found to be polycyclic polyprenylated acylphloroglucinols (PPAPs). HS distinctly alleviated DSS-stimulated UC-like lesions symptoms as evidenced by a significant recovery from body weight, colon lengths, and histological injuries of colons. HS reduced the accumulation of pro-inflammatory cytokines and improved the mRNA level of IL-10. Simultaneously, the colonic mRNA expression levels of IL-1β, IL-17, iNOS and COX-2 were all significantly suppressed by HS in a dose-dependent manner. Furthermore, HS restored the protein expression of tight junction-associated protein (ZO-1 and occluding). Besides, HS significantly inhibited the protein level of PDE4 and decreased the expressions of PKA and phosphorylated CREB.

CONCLUSION

This is the first work about main composition and anti-UC effect of Hypericum sampsonii Hance. For the first time, this study reveals HS is not toxic in a single dose and exert significantly protective effect in DSS-colitis mice. The underlying mechanisms may involve the improvement to inflammatory status, the protection for intestinal barrier function, the inhibition of PDE4, and the activation of PKA/CREB signaling pathway. This study provided an experimental basis for the traditional application of H. sampsonii Hance in the treatment of diarrhea and dysentery.

Four new polycyclic polyprenylated acylphloroglucinols from Hypericum wilsonii and their glucose uptake bioactivities

Wilsonglucinols H-K (1-4), four new polycyclic polyprenylated acylphloroglucinols (PPAPs), and eight known compounds (5-12) were isolated and identified from the aerial parts of Hypericum wilsonii. Their planner structures were confirmed via extensive NMR and HRESIMS data analysis. The absolute configurations of the new compounds were mainly determined by NMR calculation and electronic circular dichroism (ECD) calculation. Compounds 1, 6, 8, and 10 showed glucose uptake activities at 30 μg/mL, in which compound 6 showed the strongest effect and increased the glucose uptake by 2.73 folds.

Two new polycyclic polyprenylated acylphloroglucinols derivatives from Hypericum acmosepalum

Polycyclic polyprenylated acylphloroglucinols (PPAPs) were mainly obtained from the plants of Hypericum genus of Guttiferae family, and possessed intriguing chemical structures and appealing biological activities. Two new PPAPs derivatives, hyperacmosin C (1) and hyperacmosin D (2) were isolated from H. acmosepalum. Their structures were established by NMR, HREIMS, and experimental electronic circular dichroism spectra. Besides, compound 1 showed significant hepatoprotective activity at 10 µM against paracetamol-induced HepG2 cell damage and compound 2 could moderately increase the relative glucose consumption.

Structurally diverse polyprenylated acylphloroglucinols from Hypericum uralum Buch.-Ham. ex D. Don

Uralins A - D, four undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) featuring an unprecedented fused hexacyclic architecture, a unique monocyclic tetra-seco-tetranor-b-PPAP, an oxidative b-PPAP and a rare norspiroindane-type m-PPAP, respectively, were isolated from the aerial parts of Hypericum uralum, along with ten known PPAPs. Their structures and absolute configurations were elucidated by extensive spectroscopic techniques (MS, NMR, [α]_D, CD), conceivable biogenetic pathways and time-dependent density functional theory-based electronic circular dichroism (TDDFT-ECD) calculations. Biological assays showed three b-PPAPs had moderate antioxidative damage activities, while spiroindanes exhibited moderate cytotoxic effects.

Hypseudohenrins I - K: three new polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum pseudohenryi

Three previously unidentified polycyclic polyprenylated acylphloroglucinols (PPAPs) derivatives, hypseudohenrins I-K (1-3), along with a known analogue hyphenrone X (4), were isolated from the aerial part of Hypericum pseudohenryi. The structures of the new compounds were elucidated by NMR spectroscopy and ECD calculation. The anti-inflammatory activity of the compounds was evaluated. Compounds 1-3 showed mild anti-inflammatory activity while hyphenrone X showed prominent anti-inflammatory activity.[Formula: see text].

Anti-adipogenicadamantane type polycyclic polyprenylated acylphloroglucinols from Hypericum subsessile

Hypersubones D-H (1-5), five new polycyclic polyprenylated acylphloroglucinols (PPAPs) type metabolites with intriguing adamantane and homo-adamantane skeletons, were characterized from aerial parts of Hypericum subsessile. Compounds 1-2 were elucidated to share an adamantane core with 28,29-expoxide moiety, while 3-5 were homo-adamantane type PPAPs sharing a1,2-dioxepane ring system. Their structures were determined on the basis of comprehensive NMR and MS spectroscopic data.The anti-adipogenesis activities of these isolates were evaluated through employing 3T3-L1 cells as an in vitro system using oil red O staining, and compounds 1, 2 and 5 were able to significant inhibit the adipocyte differentiation, which implied that these compounds possessed anti-adipogenic activity.

Polycyclic polyprenylated acylphloroglucinols from Hypericum choisianum

Twenty-one polycyclic polyprenylated acylphloroglucinols, including three new compounds named as hyperichoisins A (3), B (14) and C (21), were isolated from the aerial parts of Hypericum choisianum. The structures of those new compounds were elucidated by analysis of mass, NMR data, and chiroptical properties. A bioassay showed that otogirinin B had significant inhibitory effect on cell proliferation of A549.

homo-Adamantane type polycyclic polyprenylated acylphloroglucinols from Hypericum hookerianum

Hookeriones I-Q (1-9), nine new homo-adamantane type polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from Hypericum hookerianum, along with twenty known analogues. These structures were determined on the basis of comprehensive NMR and MS spectroscopic data. Comprehensive analysis of the NMR data revealed the correlations between the configuration of H-18 and H-28 and the chemical shifts of related signals. The cytotoxicity and anti-allergic activities of the new isolates were evaluated, and several ones exhibited moderate cytotoxicity against ECA-109 cell lines.

13C-NMR dereplication of Garcinia extracts: Predicted chemical shifts as reliable databases

Usually isolated from Garcinia (Clusiaceae) or Hypericum (Hypericaceae) species, some Polycyclic Polyprenylated AcylPhloroglucinols (PPAPs) have been recently reported as potential research tools for immunotherapy. Aiming at exploring the chemodiversity of PPAPs amongst Garcinia genus, a dereplication process suitable for such natural compounds has been developed. Although less sensitive than mass spectrometry, NMR spectroscopy is perfectly reproducible and allows stereoisomers distinction, justifying the development of ¹³C-NMR strategies. Dereplication requires the use of databases (DBs). To define if predicted DBs were accurate enough as dereplication tools, experimental and predicted δ_C of natural products usually isolated from Clusiaceae were compared. The ACD/Labs commercial software allowed to predict 73% of δ_C in a 1.25 ppm range around the experimental values. Consequently, with these parameters, the major PPAPs from a Garcinia bancana extract were successfully identified using a predicted DB.

Polyprenylated acylphloroglucinols from Hypericum scabrum

Fourteen phloroglucinols, named hyperciumoxide A-N, and a known compound were isolated from air-dried aerial parts of Hypericum scabrum. The structures of these compounds were deduced on the basis of extensive 1D- and 2D-NMR experiments. Hepatoprotective properties against D-galactosamine-induced HL-7702 cell damage of isolated compounds were evaluated. Meanwhile, these compounds were also tested for antidepressant activity by inhibiting reuptake of tritiated serotonin ([³H]-5-HT) and Noradrenalinet ([³H]-NE) in rat brain synaptosomes.

Asymmetric, stereodivergent synthesis of (-)-clusianone utilizing a biomimetic cationic cyclization

We report a stereodivergent, asymmetric total synthesis of (-)-clusianone in six steps from commercial materials. We implement a challenging cationic cyclization forging a bond between two sterically encumbered quaternary carbon atoms. Mechanistic studies point to the unique ability of formic acid to mediate the cyclization forming the clusianone framework.

Total syntheses of hyperforin and papuaforins A-C, and formal synthesis of nemorosone through a gold(I)-catalyzed carbocyclization

The remarkable biological activities of polyprenylated polycyclic acylphloroglucinols (PPAPs) combined with their highly decorated bicyclo[3.3.1]nonane-2,4,9-trione frameworks have inspired synthetic organic chemists over the last decade. The concise total syntheses of four natural products PPAPs; hyperforin and papuaforins A-C, and the formal synthesis of nemorosone are reported. Key to the realization of this strategy is the short and scalable synthesis of densely substituted PPAP scaffolds through a gold(I)-catalyzed 6-endo-dig carbocyclization of cyclic enol ethers for late-stage functionalization.