Hyperforatins L-U: Prenylated acylphloroglucinols with a terminal double bond from Hypericum perforatum L. (St John's Wort).

Hyperforatins L-U, ten undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) bearing a terminal double bond, together with a known compound hypericumoxide J, were isolated from the aerial parts of Hypericum perforatum L. Their structures were elucidated by spectroscopic methods, including HRESIMS, IR, UV, and NMR (1H, 13C, DEPT, HSQC, HMBC, 1H-1H COSY, and NOESY experiments). Their absolute configurations were determined by comprehensive analyses of their experimental ECD spectra in conjunction with a modified Mosher's method. Evaluation of their neuroprotective activities highlighted hyperforatin L, which displayed mild activity at a concentration of 10 µM.

Anti-Inflammatory Activities of Leaf Oil from Cinnamomum subavenium In Vitro and In Vivo.

The study determined the chemical constituents and anti-inflammatory effects of leaf oil from Cinnamomum subavenium (CS-LO) that has been used in folk medicine to treat various symptoms including inflammation. The anti-inflammatory effects of the oil were evaluated by LPS-stimulated RAW264.7 cells and the Carr-induced hind mouse paw edema model, respectively. In vitro, nitric oxide (NO), prostaglandin E2 (PGE2), TNF-α, IL-6, and IL-1ß were significantly decreased by CS-LO, and the expression of nuclear factor-κB (NF-κB) protein was blocked as well. In in vivo, the malondialdehyde (MDA) and paw edema levels were decreased by CS-LO, and the same result came up on the NO and tumor necrosis factor (TNF-a) of serum at the 5th h after Carr injection. In addition, iNOS and COX-2 immunoreactive cells of the paw tissue were decreased significantly by CS-LO (200 mg/kg) in histological examination. The present findings indicated that CS-LO have anti-inflammatory properties, and the effects might be caused through inhibiting iNOS, COX-2, TNF-α, IL-1ß, and IL-6 expression via affecting NF-κB pathway, which will provide a power scientific basis for CS-LO to be used as the treatment of inflammatory diseases.

Bioactive polycyclic polyprenylated acylphloroglucinols from Hypericum perforatum.

Fifteen new polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperforatones A-O (1-15), along with 3 structurally related analogues (16-18), were isolated from the stems and leaves of Hypericum perforatum. Their structures and absolute configurations were established by a combination of NMR spectroscopic analyses, experimental and calculated electronic circular dichroism (ECD), modified Mosher's methods, Rh2(OCOCF3)4- and [Mo2(OAc)4]-induced ECD, X-ray crystallography, and the assistance of quantum chemical predictions (QCP) of 13C NMR chemical shifts. Compound 5 was found to be the first PPAP decorated by a rare 2,2,4,4,5-(pentamethyltetrahydrofuran-3-yl)methanol moiety and an oxepane ring. Furthermore, the isolates were screened for their acetylcholinesterase (AChE) and ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities. Compounds 5, 10, 11, and 15 showed desirable AChE inhibitory activities (IC50 6.9-9.2 µM) and simultaneously inhibited BACE1 (at a concentration of 5 µM) with inhibition rates of 50.3%, 34.3%, 47.2%, and 34.6%, respectively. Interestingly, compound 5 showed the most balanced inhibitory activities against both AChE and BACE1 of all the tested compounds, which means that 5 could serve as the first valuable dual-targeted PPAP for the treatment of Alzheimer's disease. Preliminary molecular docking studies of 5 with BACE1 and AChE were also performed.

Phenylacetylene-bearing 3,4-seco-cleistanthane diterpenoids from the roots of Phyllanthus glaucus.

Three new cleistanthane diterpenoids, phyllanglins A-C (1-3), a new natural product, 4-acetyl-bergenin (4), and three known compounds (5-7) were isolated from the roots of Phyllanthus glaucus. Their structures were elucidated by extensive spectroscopic data analyses and single-crystal X-ray diffraction. Phyllanglins A-C were unusual cleistanthane diterpenoids with phenylacetylene moieties, and a plausible biogenetic pathway was proposed to discuss the origins of them. All of the isolates were evaluated for their anti-inflammatory activities.

Protoilludane, Illudalane, and Botryane Sesquiterpenoids from the Endophytic Fungus Phomopsis sp. TJ507A.

To explore the chemical diversity of metabolites from endophytic fungi, the strain Phomopsis sp. TJ507A, isolated from the medicinal plant Phyllanthus glaucus, was investigated. A 2,3- seco-protoilludane-type sesquiterpenoid (1), eight protoilludane-type sesquiterpenoids (2-9), four illudalane-type sesquiterpenoids (10a/10b, 11, and 12), and a botryane-type sesquiterpenoid (13) in addition to seven known sesquiterpenoids (14-20) were identified from the liquid culture of the fungus. Structures of the isolated compounds, including their absolute configurations, were elucidated based on extensive spectroscopic analyses, a modified Mosher analysis, electronic circular dichroism (ECD) calculations, and [Rh2(OCOCF3)4]-induced ECD spectra as well as X-ray crystallographic analyses. Compound 1 represents the first example of a naturally occurring sesquiterpenoid containing the unusual 2,3- seco-protoilludane scaffold. Compounds 1 ( p < 0.001); 2-6, 15, and 18 ( p < 0.01); and 7, 9, and 20 ( p < 0.05) displayed ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities ranging from 19.4% to 43.8% at the concentration of 40 µM. LY2811376 was used as the positive control with an inhibitory activity of 38.6% ( p < 0.01). Furthermore, none of these compounds showed obvious hepatotoxicity at concentration of 40 µM.

Azacoccones A-E, five new aza-epicoccone derivatives from Aspergillus flavipes.

Azacoccones A-E (1-5), five new aza-epicoccone derivatives, were isolated from the culture of Aspergillus flavipes. Their structures were determined by extensive NMR spectroscopic analyses and the absolute configuration of 5 was determined by electronic circular dichroism (ECD) calculation. Compounds 1-5 are proposed to be generated via a Pictet-Spengler reaction-based biosynthetic route starting from the precursor flavipin. Pictet-Spengler reaction is rarely found in the fungal kingdom, which indicated the distinctive nature of 1-5. Compounds 3 and 5 exhibit significant free radical scavenging activities with IC50 values of 4.0 and 2.4µg/mL, respectively, which are better than the positive control trolox (4.55µg/mL).

Atrichodermones A-C, three new secondary metabolites from the solid culture of an endophytic fungal strain, Trichoderma atroviride.

An endophytic fungal strain named Trichoderma atroviride was isolated from the bulb of Lycoris radiata. Following cultivation on rice medium, a novel 3-amino-5-hydroxy-5-vinyl-2-cyclopenten-1-one dimer, atrichodermone A (1), a new cyclopentenone derivative, atrichodermone B (2), and a new sesquiterpene, atrichodermone C (3), together with three known cyclopentenone derivatives (4-6) were isolated. Their structures were elucidated by extensive spectroscopic (UV, IR, ECD, HRESIMS, and NMR) data analyses, and absolute configurations of the new compounds were determined by comparing their experimental ECD spectra with structurally similar compounds and computational analyses of their electronic circular dichroism (ECD) spectra. Compounds 1-3 were evaluated for their cytotoxicity against HL60 and U937 cell lines, as well as anti-inflammatory effect against the production of the pro-inflammatory cytokines TNF-α and IL-1ß.

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.

Diterpenoids of the Cassane Type from Caesalpinia decapetala.

Eighteen compounds, including eight new cassane-type furanoditerpenoids, 3ß-hydroxyphanginin H (1), 3ß-acetoxyphanginin H (2), 7ß-acetoxyphanginin H (3), 7ß-hydroxyphanginin H (4), 4-epi-3ß-hydroxycaesalpinilinn (5), 4-epi-3ß-acetoxycaesalpinilinn (6), 20-acetoxytaepeenin D (7), and tomocin E (8), along with 10 known compounds (9-18) were isolated from the roots of Caesalpinia decapetala. Compounds 1-13 were isolated from C. decapetala for the first time. The new compounds with their absolute configurations were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1, 4, 5, 7, and 11 exhibited inhibitory activities against the SW1990 human pancreatic cancer cell line with IC50 values ranging from 2.9 to 8.9 µM.

6,8-Di-C-methyl-flavonoids with neuroprotective activities from Rhododendron fortunei.

Six 6,8-di-C-methyl-flavonoids, (2R,3R)-6,8-di-C-methyl-5,7,4'-trihydroxyflavanonol 7-O-ß-d-gluco-pyranoside (1), (2R,3R)-6,8-di-C-methyl-5,7,4'-trihydroxyflavanonol 7-O-ß-d-xylopyranosyl(1→6)-ß-d-glucopyranoside (2), 6,8-di-C-methylkaempferol 7-O-ß-d-glucopyranoside (3), (2R)-farrerol (4a), (2R/2S)-farrerol 7-O-ß-d-glucopyranoside (5), and (2R/2S)-farrerol 7-O-ß-d-xylopyranosyl(1→6)-ß-d-glucopyranoside (6), and four known analogues, farrerol (4b), (2R,3R)-6,8-di-C-methyldihydrokae-mpferol (7), 6,8-di-C-methylkaempferol 7-O-ß-d-glucopyranoside (8), and 6,8-di-C-methylkaempferol (9), were isolated from the twigs and leaves of Rhododendron fortunei. The structures of compounds 1-9 were determined by spectroscopic analyses (HRESIMS, 1D and 2D NMR, and CD) and chemical methods. Compounds 1-9 were evaluated for their neuroprotective effects on the human neuroblastoma SH-SY5Y cells apoptosis induced by hydrogen peroxide (H2O2) and amyloid ß peptide (Aß), respectively. Compounds 1-3 and 5-9 exhibited significant neuroprotective effects against H2O2-induced SH-SY5Y cell apoptosis, and compound 8 exhibited the strongest activity with a improvement of cell viability by about 30% at the concentration of 10µM. Compounds 1-9 showed significant neuroprotective effects against Aß-induced SH-SY5Y cell apoptosis.

(±)-Japonones A and B, two pairs of new enantiomers with anti-KSHV activities from Hypericum japonicum.

Two pairs of new enantiomers with unusual 5,5-spiroketal cores, termed (±)-japonones A and B [(±)-1 and (±)-2], were obtained from Hypericum japonicum Thunb. The absolute configurations of (±)-1 and (±)-2 were characterized by extensive analyses of spectroscopic data and calculated electronic circular dichroism (ECD) spectra, the application of modified Mosher's methods, and the assistance of quantum chemical predictions (QCP) of (13)C NMR chemical shifts. Among these metabolites, (+)-1 exhibited some inhibitory activity on Kaposi's sarcoma associated herpesvirus (KSHV). Virtual screening of (±)-1 and (±)-2 were conducted using the Surflex-Dock module in the Sybyl software, and (+)-1 exhibited ability to bind with ERK to form key interactions with residues Lys52, Pro56, Ile101, Asp165, Gly167 and Val99.

Enantiomeric Lignans and Neolignans from Phyllanthus glaucus: Enantioseparation and Their Absolute Configurations.

Eight pairs of enantiomeric neolignans, norlignans, and sesquineolignans (1a/1b-8a/8b), together with five known neolignans (9a/9b and 10-12), have been isolated from 70% acetone extract of the whole plants of Phyllanthus glaucus Wall. (Euphorbiaceae). The racemic or partial racemic mixtures were successfully separated by chiral HPLC using different types of chiral columns with various mobile phases. Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configurations of 2a/2b were determined by computational analysis of their electronic circular dichroism (ECD) spectrum, and the absolute configurations of other isolates were ascertained by comparing their experimental ECD spectra and optical rotation values with those of structure-relevant compounds reported in literatures. Compounds 4a/4b featured unique sesquineolignan skeletons with a novel 7-4'-epoxy-8'-8''/7'-2'' scaffold, consisting of an aryltetrahydronaphthalene and a dihydrobenzofuran moiety. The planar structures of compounds 2, 3, 7, and 8 were documented previously; however, their absolute configurations were established for the first time in this study. The antioxidant activities of 1a/1b-8a/8b were evaluated using DPPH free radical scavenging assay, and the results demonstrated that compounds 1b and 3b showed potent DPPH radical scavenging activities with IC50 values of 5.987 ± 1.212 and 9.641 ± 0.865 µg/mL, respectively.

A New Megastigmane Sesquiterpenoid from Zanthoxylum Schinifolium Sieb. et Zucc.

Zanthoxylum schinifolium Sieb. et Zucc. (Rutaceae), a dioecious shrub with hooked prickly branches, has been used as folk medicine for the treatment of the common cold, stomach ache, diarrhea, and jaundice in China, Korea, and Japan. In our phytochemical investigations on this genus, a new megastigmane sesquiterpenoid, which is referred to as schinifolenol A (1), was isolated from Z. schinifolium. The stereochemistry was characterized via the analyses of extensive spectra. The absolute configuration was established by the application of a modified Mosher's experiment and assisted by a time-dependent density functional theory (TD-DFT) on calculated electronic circular dichroism (ECD). Bioactivity screenings showed that compound 1 exhibited a safe hypotoxicity and a better selectivity on anti-Kaposi's sarcoma associated herpes virus (KSHV).

Galanthamine, Plicamine, and Secoplicamine Alkaloids from Zephyranthes candida and Their Anti-acetylcholinesterase and Anti-inflammatory Activities.

Sixteen new alkaloids belonging to the galanthamine (1-6), plicamine (7-14), and secoplicamine (15 and 16) classes, together with eight known analogues (17-24), were isolated from Zephyranthes candida. The structures of 1-16 were determined by extensive spectroscopic analyses, and the absolute configurations of 1, 2, 7, 8, and 17 were confirmed by single-crystal X-ray diffraction analysis. The orientation of 3-OCH3 in N-methyl-5,6-dihydroplicane (22) was revised. Alkaloids 3, 12-14, and 18-21 exhibited anti-acetylcholinesterase activities with IC50 values ranging from 0.48 to 168.7 µM. Compounds 10-12, 14, and 16 showed in vitro anti-inflammatory activities with IC50 values ranging from 7.50 to 23.55 µM.

Hyperisampsins H-M, Cytotoxic Polycyclic Polyprenylated Acylphloroglucinols from Hypericum sampsonii.

Six new polycyclic polyprenylated acylphloroglucinols (PPAPs), named hyperisampsins H-M (1-6), were isolated from the aerial parts of Hypericum sampsonii, together with five known analogs (7-11). The structures of 1-6 were established by extensive spectroscopic analyses, including HRESIMS and NMR. In addition, the absolute configurations of these new compounds were determined by electronic circular dichroism (ECD) calculations. Compounds 1 and 2 represent the first examples of PPAPs possessing a unique γ-lactone ring at C-23, while 3-6 differed from normal PPAPs with an unprecedented 1,2-dioxane ring. Compounds 1-7 were evaluated for their cytotoxic activities against a panel of human cancer cell lines in vitro, of which 3, 4, and 6 exhibited significant cytotoxic activities with IC50 values ranging from 0.56 to 3.00 µM. Moreover, compound 3 induces leukemia cell apoptotic death, evidenced by activation of caspase-3, degradation of PARP, up-regulation of Bax, and down-regulation of Bcl-2 and Bcl-xl.

Three new 1α-alkyldaphnane-type diterpenoids from the flower buds of Wikstroemia chamaedaphne.

Three new 1α-alkyldaphnane type diterpenoids, wikstroelides R-T (1-3), together with three known analogs, genkwadane C (4), pimelea factors S6 (5) and S7 (6), two known 1α-alkyldaphnane ketal-lactone type diterpenoids, pimelotides A (7) and C (8), and a known daphnane type diterpenoid, simplexin (9), were isolated from the flower buds of Wikstroemia chamaedaphne. Their structures were elucidated by a combination of spectroscopic analyses including HRESIMS and NMR. Compounds 1-9 were evaluated for their cytotoxic activities in vitro, and most of them exhibited moderate cytotoxic activities with IC50 values ranging from 8.7-22.0 µM.

Coumarin derivatives from Ainsliaea fragrans and their anticoagulant activity.

Coumarin derivatives are an important class of C6-C3 plant metabolites that show a variety of bioactivities. Currently, most clinical anticoagulant agents are coumarins, such as warfarin, dicoumarol and acenocoumarol, and patients taking these drugs must be monitored for adverse reactions. In a search for safe and effective anticoagulant compounds from Chinese herbal medicine, a screening procedure on the whole plant of Ainsliaea fragrans was performed. The phytochemical investigation of this plant afforded five new coumarin derivatives, including a pair of natural 4-hydroxycoumarin enantiomers (1), a pair of coumarin enantiomers with a rare polycyclic pyrano[3-2c] carbon skeleton (2) and a 7-hydroxycoumarin derivative (3), together with 5 known biogenetically related compounds (4-8). Enantioseparation of 1 and 2 produced optically pure compounds 1a, 1b, 2a and 2b. The absolute configurations of the new compounds were confirmed by single-crystal X-ray diffraction analysis. In addition, we evaluated the anticoagulant activity of all isolates via activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) assays in vitro and in vivo. Of note, compound 3 displayed potent anticoagulant activity and no significant hepatic or renal toxicity, which could make it a promising agent for further preclinical evaluation for preventing abnormal blood clotting.

(±)-Acortatarinowins A-F, Norlignan, Neolignan, and Lignan Enantiomers from Acorus tatarinowii.

Three pairs of new 8-O-4'-type dinorneolignan enantiomers, (±)-acortatarinowins A-C (1a/1b-3a/3b), a pair of new 8-O-4'-type (4a/4b) and a pair of rare C7-C8'-type (5a/5b) neolignan enantiomers, (±)-acortatarinowins D and E, and a pair of new furofuran-type lignan enantiomers, (±)-acortatarinowin F (6a/6b), along with two pairs of known lignan enantiomers (7a/7b and 8a/8b), were obtained from the rhizomes of Acorus tatarinowii. The separation of 1-8 by chiral HPLC using a Daicel IC column led to the isolation of eight pairs of enantiomers, 1a/1b-8a/8b, which had variable enantiomeric excess (ee) values of approximately 66, 71, 63, 60, 0, 38, 48, and 75%, respectively. The structures were elucidated by extensive spectroscopic and chemical methods, and their absolute configurations were determined by a combined analysis of single-crystal X-ray diffraction and a modified Mosher's method, assisted by experimental and calculated electronic circular dichroism data. Among them, compounds 1a, 3a, 6b, 8a, and 8b showed weak inhibitory activities against NO production in activated macrophages with IC50 values ranging from 23.3 to 38.0 µM, respectively.

Grayanane and leucothane diterpenoids from the leaves of Rhododendron micranthum.

Eleven grayanane diterpenoids, 1-epi-grayanotoxin IV, 1-epi-grayanotoxin II, 6-deoxy-1-epi-grayanotoxin XVII, 6-deoxygrayanotoxin XVII, 16-acetylgrayanotoxin II, 3-oxograyanotoxin IX, 14-deoxygrayanotoxin VIII, 14-acetylisograyanotoxin II, rhodomicranols C-E, and a leucothane diterpenoid, rhodomicranol F, together with eleven known diterpenoids were isolated from leaves of Rhododendron micranthum. Their structures were elucidated by spectroscopic analyses, with the absolute configurations of 1-epi-grayanotoxin IV and rhodomicranol C determined by single-crystal X-ray diffraction with Cu Kα radiation, and the structures of 14-acetylisograyanotoxin II and known grayanotoxins IX and X confirmed by single-crystal X-ray diffraction. All twenty-three diterpenoids were evaluated for their in vitro immunomodulatory activities, and none showed significant immunomodulatory activities in a dose-dependent manner. In addition, they are non-toxic to the murine lymphocytes in the general cytotoxicity assay.

Neolignans with a Rare 2-Oxaspiro[4.5]deca-6,9-dien-8-one Motif from the Stem Bark of Cinnamomum subavenium.

Two pairs of racemic spirodienone neolignans with a rare 2-oxaspiro[4.5]deca-6,9-dien-8-one motif, named (±)-subaveniumins A (1) and B (2), were isolated from the bark of Cinnamomum subavenium. The chiral separation of the (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers was accomplished via high-performance liquid chromatography on a chiral column. Their structures were elucidated using single-crystal X-ray diffraction and spectroscopic analyses (UV, IR, HRESIMS, and 1D and 2D NMR). The absolute configurations of the enantiomers were determined by comparing the experimental and calculated electronic circular dichroic spectra. The (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers exhibited moderate inhibitory effects against NO production in RAW264.7 mouse macrophages induced by lipopolysaccharide, with IC50 values of 17.9, 5.6, 15.1, and 4.3 µM, respectively.