Polycyclic polyprenylated acylphloroglucinols from the pericarps of Garcinia multiflora champ. ex Benth. with cytotoxic property.

The phytochemical investigation on the pericarps of Garcinia multiflora resulted in the isolation of 12 previously undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs, 1-12) with a variety of skeletons. Their structures were determined by comprehensive spectroscopic analyses, ECD calculations, and single-crystal X-ray diffraction. Compounds 6-9 possess a rare bicyclo[4.3.1]decane skeleton. Additionally, the anti-tumor activity of the 12 isolates was evaluated. The results indicated that compounds 5, 9, and 12 exhibited significant cytotoxicity in a wide range of cancer cell lines, including the human breast cancer MDA-MB-231 cells, human lung cancer A549 cells, human colon cancer SW480 cells and human ovarian cancer HEY cells. Further studies indicated that compound 5 induced cell cycle arrest and apoptosis, to inhibit the growth of MDA-MB-231 cells. Taken together, these findings expand the chemical diversity of PPAPs and further demonstrate the potential of PPAPs as candidates for cancer treatment.

New polycyclic polyprenylated acylphloroglucinols with antidepressant activities from Hypericum perforatum L.

Six new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperidiones A-F (1-6), were obtained from Hypericum perforatum L. Their structures were characterized via extensive spectroscopic analyses, the circular dichroism data of the in situ formed [Mo2(OCOCH3)4] complexes, the nuclear magnetic resonance calculation with DP4 + probability analysis, and the calculated electronic circular dichroism (ECD) spectra. Compounds 1-6 are bicyclic polyprenylated acylphloroglucinols with a major bicyclo[3.3.1]nonane-2,4,9-trione skeleton. Notably, compound 1 is a rare PPAP with a hydroperoxy group, and a plausible biosynthetic pathway for 1 was proposed. Compounds 4 and 6 exhibited significant neuroprotective effects under 10 µM against corticosterone (CORT)-injured SH-SY5Y cells. Furthermore, compound 4 demonstrated a noteworthy antidepressant effect at the dose of 5 mg/kg in the tail suspension test (TST) of mice, which was equivalent to 5 mg/kg of fluoxetine. And it potentially exerted an antidepressant effect through the hypothalamic-pituitary-adrenal (HPA) axis.

Three New Polyprenylated Benzophenone Derivatives Isolated from Clusia burle-marxii.

Three new polyprenylated benzophenone derivatives named burlemarxione G-I (1-3) were isolated from C. burle-marxii trunks (compound 1) and leaves (compounds 2 and 3), along with the known compound burlemarxione F. Burlemarxione G (1) was isolated after methylation with diazomethane and it is the keto-enol tautomeric pair of burlemarxione F. Burlemarxione H (2) derives from burlemarxiones F and G, but it has additional rings due to cyclization of the prenyl group attached to C-5 that establishes new single bonds between C-1 and C-23, as well as, between C-24 and C-29. Burlemarxione I (3) has two additional cyclizations: the first encompasses the cyclization of the former isopentenyl group into an 11,11-dimethyl-six-membered ring, whereas the second produces additional rings due to the cyclization of the prenyl group attached to C-5 that establishes new single bonds between C-1 and C-23, as well as, between C-24 and C-29. All three compounds showed moderate anti-glioma activity. These results show that C. burle-marxii is an important source of sophisticated polyprenylated benzophenone derivatives.

Spirohypertones A and B as potent antipsoriatics: Tumor necrosis factor-α inhibitors with unprecedented chemical architectures.

Tumor necrosis factor-α (TNF-α) is a promising target for inflammatory and autoimmune diseases. Spirohypertones A (1) and B (2), two unprecedented polycyclic polyprenylated acylphloroglucinols with highly rearranged skeletons, were isolated from Hypericum patulum. The structures of 1 and 2 were confirmed through comprehensive spectroscopic analysis, single-crystal X-ray diffraction and electronic circular dichroism calculations. Importantly, 2 showed remarkable TNF-α inhibitory activity, which could protect L929 cells from death induced by co-incubation with TNF-α and actinomycin D. It also demonstrated the ability to suppress the inflammatory response in HaCaT cells stimulated with TNF-α. Notably, in an imiquimod-induced psoriasis murine model, 2 restrained symptoms of epidermal hyperplasia associated with psoriasis, presenting anti-inflammatory and antiproliferative effects. This discovery positions 2 as a potent TNF-α inhibitor, providing a promising lead compound for developing an antipsoriatic agent.

Garciyunnanones A-R: Caged polycyclic polyprenylated acylphloroglucinols decorated with a lavandulyl substituent from Garcinia yunnanensis.

Garciyunnanones A-R (1-18), eighteen undescribed caged polycyclic polyprenylated acylphloroglucinols, two undescribed biogenetic congeners (19-20), and nineteen known analogues (21-39), were isolated from the stem barks of Garcinia yunnanensis Hu. All of these isolates are decorated with a C-5 lavandulyl substituent. Their structures and absolute configurations were confirmed by HRESIMS, 1D & 2D NMR spectroscopic analysis, quantum chemical calculations of electronic circular dichroism data, and single-crystal X-ray diffraction analysis. The X-ray crystallographic data of ten isolated caged compounds ascertained the absolute configuration of C-23 in the lavandulyl as S. The cytotoxicity on three cancer cell lines and the anti-nonalcoholic steatohepatitis activity of the isolates were tested. In a free fatty acid-induced L02 cell model, compounds 33 and 39 decreased intracellular lipid accumulation significantly.

Hyparillums A and B: polycyclic polyprenylated acylphloroglucinols from Hypericum patulum.

Hyparillums A (1) and B (2), two previously unidentified polycyclic polyprenylated acylphloroglucinols (PPAPs) with intricate architectures, were isolated from Hypericum patulum Thunb. Hyparillum A was the first PPAP with eight-carbon rings based on an unprecedented 6/6/5/6/6/5/6/4 octocyclic system featuring a rare heptacyclo[10.8.1.11,10.03,8.08,21.012,19.014,17]docosane core. In contrast, hyparillum B featured a novel heptacyclic architecture (6/6/5/6/6/5/5) based on a hexacyclo[9.6.1.11,9.03,7.07,18.011,16]nonadecane motif. Furthermore, hyparillums A and B demonstrated promising inhibitory effects on the proliferation of murine splenocytes stimulated by anti-CD3/anti-CD28 monoclonal antibodies and lipopolysaccharide, exhibiting half-maximal inhibitory concentration (IC50) values ranging from 6.13 ± 0.86 to 12.69 ± 1.31 µmol·L-1.

Hyperatins A-D, highly oxidized polycyclic polyprenylated acylphloroglucinols from Hypericum perforatum L. with hypoglycemic potential in liver cells.

Hyperatins A-D (1-4), four previously undescribed polycyclic polyprenylated acylphloroglucinols, were isolated from Hypericum perforatum L. (St. John's wort). Compound 1 possessed a unique octahydroindeno[1,7a-b]oxirene ring system with a rare 2,7-dioxabicyclo[2.2.1]heptane fragment. Compounds 2-4 had an uncommon decahydrospiro[furan-3,7'-indeno[7,1-bc]furan] ring system. Their structures were established by spectroscopic analyses and X-ray crystallography. Plausible biosynthetic pathways of 1-4 were also proposed. Compounds 1 and 2 exerted promising hypoglycemic activity by inhibiting glycogen synthase kinase 3 expression in liver cells.

Two rearranged acylphloroglucinols with moderate neuroprotective effects from Hypericum ascyron Linn.

Phytochemical studies on the leaves and twigs of Hypericum ascyron Linn. led to the isolation of two previously undescribed rearranged polycyclic polyprenylated acylphloroglucinols (PPAP) with a 4,5-seco-3(2H)-furanone skeleton, named hyperascone A and B (1-2). Additionally, a known PPAP tomoeone A (3) and two known xanthones 1,3,5 -trihydroxy-6-O-prenylxanthone (4) and 3,7-dihydroxy-1,6-dimethoxyxanthone (5) were also isolated. The structures of the compounds were determined by the analysis of their spectroscopic data including HRMS, NMR and ECD. All of the five isolated compounds exhibited neuroprotective effects against MPP+ and microglia activation induced damage of SH-SY5Y cells.

Discovery of adamantane-type polycyclic polyprenylated acylphloroglucinols that can prevent concanavalin A-induced autoimmune hepatitis in mice.

Hyperadamans A-G (1-7), seven new adamantane type polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from Hypericum wilsonii N. Robson. Structurally, 1-4 were the first adamantanes bearing an unusual 2,7-dioxabicyclo-[2.2.1]-heptane fragment, and compound 5 was the first adamantane with a rare 1,6-dioxaspiro[4.4]nonane section. Importantly, 1-7 exhibited significant immunosuppressive activity on Con A-induced T-lymphocyte proliferation in vitro, with IC50 values ranging from 3.97 ± 0.10 to 18.12 ± 1.07 µM. Pretreatment with 1 in Con A-challenged autoimmune hepatitis mice could dramatically ameliorate the levels of hepatic injury indexes (ALT and AST) and reduce the product of proinflammatory cytokines (COX-2, IL-6, IL-1ß, IL-18, IL-23A and TNF-α). Furthermore, the protective effect of 1 on the Con A-induced liver injury was corroborated by the histological analysis and the immunohistochemistry.

Discovery of bioactive polycyclic polyprenylated acylphloroglucinols with adamantine/homoadamantane skeletons from Hypericum wilsonii.

In this work, nine previous undescribed polycyclic polyprenylated acylphloroglucinols with adamantine/homoadamantane skeletons, cumilcinols A-I (1-9), along with six known analogues, were isolated and identified from the stems, leaves and flowers of Hypericum wilsonii. Their structures were determined by HRESIMS, NMR spectroscopic analysis, single-crystal X-ray crystallography as well as electronic circular dichroism calculations and comparisons. Compound 2 formed a unique furan ring bearing a rare acetal functionality. In bioassays, hyperacmosin G (13) could significantly inhibit the production of NO in LPS-stimulated RAW264.7 cell (IC50 = 4.350 ± 1.146 µM), and increased expression of related transcription factors at the gene level, inhibit the nuclear translocation of NF-κBp65, and reduce the protein expression of COX-2. Additionally, compound 5 showed significant inhibitory activity on Con A-induced T-lymphocyte proliferation (IC50 = 4.803 ± 3.149 µM), and treatment of 5 could reduce the increased ratio of CD4 and CD8 subpopulations induced by Con A in vitro. Those results indicated 13 possesses potential anti-inflammatory activity, and 5 exhibits a certain degree of immunosuppressive activity.

Polycyclic polyprenylated acylphloroglucinols from Hypericum sampsonii Hance and their anti-inflammatory activity.

Phytochemical investigation of Hypericum sampsonii Hance resulted in the isolation of thirty-five polycyclic polyprenylated acylphloroglucinols including six new ones (1, 3, 5, and 15-17). Their structures were elucidated by UV, IR, NMR, HRESIMS, and calculated ECD analysis. Some compounds were evaluated for their anti-inflammatory effects in LPS-induced RAW264.7 cells. Compounds 1 and 26 showed significant inhibitory effects on LPS-induced NO production, and markedly suppressed the protein expression of iNOS and COX-2 in LPS-activated RAW264.7 cells.

Isolation and antihyperglycemic effects of garcibractinols A-H, intricate polycyclic polyprenylated acylphloroglucinols from the fruits of Garcinia bracteata.

Eight previously undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) were isolated from the fruits of Garcinia bracteata and named garcibractinols A-H. Garcibractinols A-F (compounds 1-6) were bicyclic polyprenylated acylphloroglucinols (BPAPs) sharing a rare bicyclo[4.3.1]decane core. On the other hand, garcibractinols G and H (compounds 7 and 8) shared an unprecedented BPAP skeleton bearing a 9-oxabicyclo[6.2.1]undecane core. The structures andabsolute configurations of compounds 1-8 were determined by spectroscopic analysis,single-crystal X-ray diffraction analysis, and quantum chemical calculation. The breakage of the C-3/C-4 linkage through the retro-Claisen reaction was a key step in the biosynthesis of compounds 7 and 8. The antihyperglycemic effects of the eight compounds were evaluated in insulin-resistant HepG2 cells. At a concentration of 10 µM, compounds 2 and 5-8 significantly increased the glucose consumption in the HepG2 cells. Furthermore, compound 7 was more effective than metformin (which was used as a positive control) in promoting glucose consumption in the cells. The findings of this study suggest that compounds 2 and 5-8 have anti-diabetic effects.

Structurally diverse spirocyclic polycyclic polyprenylated acylphloroglucinols from Hypericum ascyron Linn. and their anti-tumor activity.

Ten spirocyclic polycyclic polyprenylated acylphloroglucinols (PPAP), hunascynols A-J (1-10), and 12 known analogs were isolated from the aerial parts of Hypericum ascyron Linn. Compounds 1 and 2, which share a 1,2-seco-spirocyclic PPAP skeleton, could be derived from spirocyclic PPAP, with a common octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core, through a cascade of Retro-Claisen, keto-enol tautomerism, and esterification reactions. Aldolization of normal spirocyclic PPAP yielded 3, which has a caged framework with a 6/5/6/5/6 ring system. The structures of these compounds were determined using spectroscopy and X-ray diffraction. The inhibitory activities of all isolates were tested in three human cancer cell lines and a zebrafish model. Compounds 1 and 2 displayed moderate cytotoxicity against HCT116 cells (IC50 6.87 and 9.86 µM, respectively). The mechanisms of these compounds were evaluated using Western blot assays. Compounds 3 and 5 inhibited the growth of sub-intestinal vessels in zebrafish embryos. Further, the target genes were screened using real-time PCR.

Kiiacylphnols A-H, eight undescribed polycyclic polyprenylated acylphloroglucinols with anticancer activities from Hypericum przewalskii Maxim.

Kiiacylphnols A-H, eight previously undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs), along with two known congeners (hyperforcinol F and oxepahyperforin), were obtained from Hypericum przewalskii Maxim. The structures of these metabolites were confirmed by spectroscopic analyses, quantum-chemical 1H and 13C NMR calculations with DP4+ analyses, electronic circular dichroism (ECD) comparisons and calculations. Kiiacylphnols A and B were the first [3.3.1]-type PPAPs with an unusual octahydrooxireno[2,3-i]chromene scaffold bearing a rare 6/6/6/3 ring system. More significantly, kiiacylphnol A and oxepahyperforin displayed cytotoxicity against acute myeloid leukemia and diffuse large B-cell lymphoma cell lines by inducing cell apoptosis.

Chemical constituents from the flowers of Hypericum monogynum L. with COX-2 inhibitory activity.

Hypericum monogynum L. (Hypericaceae) has been used as a folk Chinese medicine for the treatment of inflammatory related diseases. Cyclooxygenase-2 (COX-2) is a crucial target for the development of agents to treat inflammation. To search for anti-inflammatory compounds from traditional Chinese medicines, a chemical constituent study along with COX-2 inhibitory activity analysis was performed for this plant. In this study, sixteen chemical monomers, including three undescribed oxidative degradation polycyclic polyprenylated acylphloroglucinols (PPAPs, hypemoins C-E), two undescribed PPAPs (hypemoins A and B), and 11 known compounds, were identified from the flowers of H. monogynum. Their structures were characterized by HRESIMS, NMR techniques, ECD, and single crystal X-ray diffraction. Four flavonoid derivatives showed remarkable COX-2 inhibitory activities, with IC50 values ranging from 0.220 ± 0.006 to 1.655 ± 0.098 µM. Among these compounds, the possible recognition mechanism between quercetin 3-(6″-O-caffeoyl)-ß-3-D-galactoside and COX-2 was predicted by molecular docking analysis. Moreover, the multidrug resistance reversal activities for the selected compounds were evaluated.

Discovery of Novel Polycyclic Polyprenylated Acylphloroglucinols from the Fruits of Garcinia xanthochymus as Antitumor Agents by Suppressing the STAT3 Signaling.

Pharmacologic studies have revealed that polycyclic polyprenylated acylphloroglucinols (PPAPs) collectively exhibit a broad range of biological activities, including antineoplastic potential. Here, six new PPAPs, named garcixanthochymones F-K (3, 5, 7, 8, 11, and 15), together with nine known analogues were isolated from the fruits of Garcinia xanthochymus. Their structures were elucidated based on the spectroscopic data, including UV, HRESIMS, and NMR, and quantum chemical calculations. All the isolated PPAPs were tested for anti-proliferative activity against four human tumor cell lines, including SGC7901, A549, HepG2, and MCF-7. Most of the PPAPs possessed high anti-proliferative activity with IC50 values in the range of 0.89 to 36.98 µM, and significant apoptosis was observed in MCF-7 cells exposed to compounds 2 and 5. Besides, docking results showed that compounds 2 and 5 could strongly combine with the Src homology 2 (SH2) domain of STAT3 via hydrogen bond and hydrophobic interaction, which is one of the key oncogenes and crucial therapeutic targets. Furthermore, compounds 2 and 5 efficiently downregulated the expression of p-STAT3Tyr705 and pivotal effector proteins involved in oncogenic signaling pathways of MCF-7 cells.

Hyperpatulones C-G, new spirocyclic polycyclic polyprenylated acylphloroglucinols from the leaves of Hypericum patulum.

Five new spirocyclic polycyclic polyprenylated acylphloroglucinols, Hyperpatulones C-G (1-5), were obtained from the leaves of Hypericum patulum. Their structures were characterized by the comprehensive analysis of their IR, NMR, CD spectra and HRESIMS data. All the new compounds were evaluated for the α-glycosidase inhibitory activities. Among them, compounds 3-5 showed α-glucosidase inhibitory activities, with IC50 values of 14.06-37.69 µM.

Discovery of bioactive polycyclic polyprenylated acylphloroglucinols from Hypericum wilsonii.

Eleven new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperwilsones A-K (1-11), along with five known PPAPs (12-16), were isolated from Hypericum wilsonii. Their structures were established via spectroscopic methods, the careful analysis of calculated and experimental electronic circular dichroism (ECD) spectra, single-crystal X-ray diffraction, the modified Mosher's method, and [Rh2(OCOCF3)4]-induced ECD. Hyperwilsone A (1) and hyperwilsone B (2) possessed the unique acetal functionality. Hyperwilsone C (3) was a rare example of [3.3.1]-type PPAP possessing a 3-isopropylfuran moiety. In bioassay, compounds 9 and 10 showed potent anti-inflammatory activity against LPS-induced NO production by inhibiting the nuclear translocation of NF-κB p65 and thus reducing the production of proinflammatory cytokines. Compounds 5, 8, 11, and 14 exhibited moderate inhibitory activity against SUDHL-4 and HL60 cancer cells with IC50 values in the range of 5.74-19.82 µM.

Polycyclic polyprenylated acylphloroglucinols with immunosuppressive activity from Hypericum perforatum and absolute configurations assignment of previously reported analogues.

Hyperformitins A-I (1-9), nine undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) with double-bond migration, along with four new isomers hyperformitins J-M (10-13), were isolated from Hypericum perforatum. Their structures and absolute configurations were determined by spectroscopic analyses including HRESIMS, IR, UV, NMR, and ECD, as well as optical rotation (OR) calculations. The absolute configurations of previously reported analogues, garsubellins D and C as well as garcinielliptones L and M, were assigned for the first time by NMR spectra and specific rotations analyses assisting with OR calculations. Selected compounds were tested for their immunosuppressive activities against lipopolysaccharide (LPS)-induced B lymphocyte proliferation. Compounds 1, 3, 4, 5, 7, and 11 showed inhibition activities against the proliferation of B lymphocyte with IC50 values ranging from 4.1 to 9.7 µM. Furthermore, the neuroprotective activities of the isolates against corticosterone (CORT)-induced injury in PC12 cells were also tested, and compounds 1, 12, and 13 exhibited neuroprotective effects with cell viabilities of 68.0%, 71.3%, and 68.4%, respectively under the concentration of 10 µM.

Polycyclic polyprenylated acylphloroglucinol congeners from Garcinia yunnanensis Hu with inhibitory effect on α-hemolysin production in Staphylococcus aureus.

α-Hemolysin (Hla) is an extracellular protein secreted by methicillin-resistant Staphylococcus aureus (MRSA) strains that plays a critical role in the pathogenesis of pulmonary, intraperitoneal, intramammary, and corneal infections, rendering Hla a potential therapeutic target. In this study, 10 unreported polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives, garciyunnanins C-L (1-10), with diverse skeletons, were isolated from Garcinia yunnanensis Hu. The structures of these new compounds were determined by HRMS, NMR, electronic circular dichroism (ECD) calculations, single-crystal X-ray diffraction, and biomimetic transformation. Garciyunnanins C and D (1 and 2) were found to be potent Hla inhibitors in the anti-virulence efficacy evaluation against MRSA strain.