Hyperacmosin R, a New Decarbonyl Prenylphloroglucinol with Unusual Spiroketal Subunit from Hypericum acmosepalum.

Two previously undescribed polycyclic polyprenylated acylphloroglucinols, hyperacmosins R-S (1-2), were obtained from the aerial parts of Hypericum acmosepalum. Their structures were elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation (ECD). Compound 1 featured an unprecedented 5,8-spiroketal subunit as well as the loss of C-2' carbonyl in the phloroglucinol ring. In addition, compounds 1 and 4 showed weak hepatoprotective activity against paracetamol-induced HepG2 cell damage at 10 µm. The plausible biosynthetic pathway of 1 was proposed via a retro-Clasisen reaction and decarboxylation.

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.

Prenylaromadendrane-type diterpenoids from the gum resin of Boswellia sacra flueck and their cytotoxic effects.

Two new prenylaromadendrane-type diterpenoids, and three known analogues, were isolated from the ethanol extract of the gum resin of B. sacra Flueck. The structures of the new compounds were elucidated using 1 D and 2 D NMR spectroscopic analyses, mass spectrometric data, circular dichroism spectra, and comparison with the other compounds in the literature. One diterpenoid represents the first example of an acetoxyl-substituted prenylaromadendranoid in frankincense. All compounds exhibited notable cytotoxicity against human malignant glioma (U87-MG) cell line, with inhibitory rates exceeding that of the positive control 5-fluorouracil. However, nitric oxide inhibition induced by lipopolysaccarides was not observed in primary mouse peritoneal macrophages.

Polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum pseudohenryi.

Seven previously unidentified polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives hypseudohenrins A-G, along with six known analogs, were isolated from the aerial portion of Hypericum pseudohenryi. Their structures were determined by NMR, ECD and X-ray crystallographic spectroscopy. These compounds were screened for anti-inflammatory activity, and hypseudohenrins B and G (at the concentration of 10 µM) showed NO production inhibition ratios of 52.56% and 54.01%, respectively, which imply good anti-inflammatory activity. In particular, uraloidin A exhibited an NO inhibition ratio of 90.61%, while that ratio of the positive control compound dexamethasone was 94.88%. Additionally, anti-cancer and neural-protective activities were screened, but none of these compounds showed desirable activity.

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].

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.

Hyperacmosins K-M, three new polycyclic polyprenylated acylphloroglucinols from Hypericum acmosepalum.

Hyperacmosins K-M (1-3), three new polycyclic polyprenylated acylphloroglucinol (PPAPs) derivatives, were isolated from the air-dried aerial parts of Hypericum asmosepalum. Compounds 1 and 2 both possessed a rare 5,5-spiroketal subunit with the loss of C-2' carbonyl in the phloroglucinal ring, while compound 3 featured an unusual 1,2-seco-bicyclo[3.3.1] PPAP skeleton. Their structures were confirmed by NMR, HRESIMS, and CD spectra. The plausible biogenetic pathways of 1-3 were proposed, which gave an insight for future biomimetic synthesis of the novel compounds.

Ten undescribed cembrane-type diterpenoids from the gum resin of Boswellia sacra and their biological activities.

Ten undescribed cembrane-type diterpenes boscartins AL-AU, as well as five known analogues were isolated from Boswellia sacra Flueck. The relative configurations of these boscartins were established by extensive spectroscopic analysis of NMR spectra, IR and MS. The absolute configurations of boscartin AL, boscartin AN and isoincensole oxide were unequivocally assigned by single crystal X-ray diffraction. Meanwhile, the absolute configurations of boscartin AM, boscartin AP and boscartin AQ were determined by an empirical in situ formed Rh-complex ECD method. Biological evaluations showed that four compounds exhibited obvious hepatoprotective activities against paracetamol-induced HepG2 cell damage at 10 µM. Regarding neuroprotective activity, some isolates displayed moderate to evident protective effects against glutamate-induced toxicity in primary cultured fetal rat cortical neurons or oxygen-glucose deprivation toxicity in SK-N-SH Cells at 10 µM.

Hyperacmosins E-G, three new homoadamantane-type polyprenylated acylphloroglucinols from Hypericum acmosepalum.

Three new homoadamantane-type polyprenylated acylphloroglucinols, hyperacmosins E-G (1-3), with seven known compounds were isolated from the air-dried aerial parts of Hypericum asmosepalum. Their structures were determined by NMR, HRESIMS and experimental electronic circular dichroism (ECD) spectra. The hepatoprotective activity of these compounds were evaluated. Compounds 4 and 8 exhibited hepatoprotective activity against paracetamol-induced HepG2 cell damage.

Hyperacmosins H-J, three new polycyclic polyprenylated acylphloroglucinol derivatives from Hypericum acmosepalum.

Three new polycyclic polyprenylated acylphloroglucinol derivatives, hyperacmosins H-J (1-3), with four known compounds (4-7), were isolated from the air-dried aerial parts of Hypericum acmosepalum. Especially, compounds 1 and 2 were identified as methylated polycyclic polyprenylated acylphloroglucinol derivatives (mPPAPs). Their structures were established by NMR, HRESIMS and experimental electronic circular dichroism (ECD) spectra. The hepatoprotective activity of seven compounds were evaluated. Compounds 1 and 5 exhibited hepatoprotective activity against paracetamol-induced HepG2 cell damage.[Formula: see text].