[Chemical constituents from stem bark of Aquilaria sinensis and their antibacterial activity against Helicobacter pylori].

The stem bark of Aquilaria sinensis(Thymelaeaceae), with the local name of "Li-Wa-Zi-Xing", is used in traditional Yi medicine for treating chronic gastritis and other diseases. However, its active ingredients remain currently unknown. In this study, Helicobacter pylori(Hp) is used in anti-bacterial experiments to test the active compounds derived from A. sinensis stem bark. Nineteen compounds were isolated from the stem bark of A. sinensis by column chromatography, high-performance liquid chromatography, recrystallization, etc. Aquilaridiester(1) is a new lignan. The other eighteen compounds were reported before, including docosyl caffeate(2), 6-hydroxy-2-[2-(4-methoxyphenyl)ethyl]-4H-1-benzopyran-4-one(3), qinanone A(4), 6-hydroxy-2-(2-phenylethyl)chromone(5), 6-hydroxy-2-[2-(3-hydroxy-4-methoxyphenyl)ethyl]-4H-1-benzopyran-4-one(6), 6-hydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]-4H-1-benzopyran-4-one(7), 6-hydroxy-2-[2-(3,4-dimethoxyphenyl)ethyl]chromone(8), 6-hydroxy-2-[(1E)-2-(4-hydroxy-3-methoxyphenyl)ethenyl]-4H-1-benzopyran-4-one(9), genkwanin(10), 5-hydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-7-methoxy-4H-1-benzopyran-4-one(11), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone(12),(+)-syringaresinol(13), zhebeiresinol(14), aquilarin A(15), caruilignan D(16),(-)-ficusal(17), pistaciamide(18), and protocatechuic acid(19). The anti-bacterial results show that compounds 2-7, 10-11, and 13 have inhibitory activity against Hp. Among them, 6-hydroxy-2-(2-phenylethyl)chromone(5) and 6-hydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]-4H-benzopyran-4-one(7) have superior inhibitory effects on Hp to others, with the same minimum inhibitory concentration(MIC) of 6.25 µmol·L~(-1). The 2-(2-phenylethyl)chromones are the major active ingredients in A. sinensis stem bark.

Polyhydroxylated Spirostanol Saponins from the Rhizomes of Paris dulongensis.

Three new polyhydroxylated spirostanol steroidal saponins, dulongenosides B-D (2-4), along with 14 known compounds, dulongenoside A (1), padelaoside B (5), parisyunnanoside G (6), polyphyllin D (7), ophiopogonin C' (8), formosanin C (9), dioscin (10), paris saponin VII (11), paris H (12), parisyunnanoside I (13), protodioscin (14), proprotogracillin (15), crustecdysone (16), and stigmasterol-3-O-ß-d-glucopyranoside (17), were isolated from the rhizomes of Paris dulongensis (Melanthiaceae). Their chemical structures were elucidated based on extensive analyses of NMR and MS data and acidic hydrolyses. The isolates were evaluated for their cytotoxicity to five human cancer cell lines (HL-60, SW480, MDA-MB-231, A549, and A549/Taxol) and the normal human bronchial epithelial cell line BEAS-2B by the MTS test. Compounds 7-12 and 14 showed cytotoxic activity, with IC50 values ranging from 0.20 to 4.35 µM. Proprotogracillin selectively inhibited A549 (IC50=0.58 µM) and A549/Taxol (IC50=0.74 µM) cells, with no significant cytotoxic activity against HL-60, SW480, MDA-MB-231, or BEAS-2B cells, with IC50 values greater than 40 µM.

[Chemical constituents from Paris rugosa rhizomes and their antimicrobial activities].

Paris rugosa(Melanthiaceae) only grows in Yunnan province of China at present, and its chemical constituents have not been systematically studied. In this study, nine compounds, including one new compound pariposide G(1) and eight known compounds of cerin(2), stigmast-4-en-3-one(3), ß-ecdysone(4), ophiopogonin C'(5), methyl protogracillin(6), gracillin(7), parissaponin H(8), and parisyunnanoside G(9), were isolated and identified from the ethanol extract of P. rugosa rhizomes by column chromatography methods and semi-preparative high-performance liquid chromatography(HPLC). Compounds 1-9 were isolated from this plant for the first time. The antibacterial and antifungal activities of all the compounds were evaluated. The results showed that ophiopogonin C' had strong inhibitory effects on Candida albicans [MIC_(90)=(4.68±0.01) µmol·L~(-1)] and the fluconazole-resistant strain of C. albicans [MIC_(90)=(4.66±0.02) µmol·L~(-1)].

Heterodimers with a cucurbitane-type triterpenoid skeleton from the branches of Elaeocarpus dubius.

Four undescribed and two known cucurbitane-type triterpenoids, including two heterodimers, elaeocarpudubins A and B, were isolated from the branches of Elaeocarpus dubius (Elaeocarpaceae). The chemical structures of these undescribed isolates were determined by analyses of 1D and 2D NMR and MS data, electronic circular dichroism (ECD) calculations, and chemical transformation. Biogenetically, elaeocarpudubins A and B might be derived from cucurbitacin F through Michael addition with vitamin C and (-)-catechin, respectively. These six isolates were evaluated for their cytotoxic activities against human leukemia HL-60, human lung adenocarcinoma A549, human hepatoma SMMC-7721, human breast cancer MCF-7, human colon cancer SW480, and paclitaxel-resistant A549 (A549/Taxol) cell lines, for their antioxidant properties using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and for their differentiation effects on nerve growth factor (NGF)-mediated neurite outgrowth in rat pheochromocytoma PC12 cells. Cucurbitacins F (IC50 of 4.98-38.11 µM) and D (IC50 of 0.03-4.40 µM) showed growth-inhibitory activities against these six cancer cell lines. Elaeocarpudubin B (IC50 of 61.04 µM) and elaeocarpudoside B (IC50 of 6.93 µM) showed antioxidant activities. Elaeocarpudubin B and elaeocarpudoside B also showed neurite outgrowth-promoting activities in PC12 cells at a concentration of 10 µM.

Bioassay-guided isolation of cytotoxic constituents from the flowers of Aquilaria sinensis.

Bioassay-guided fractionation of the EtOH extract from the flowers of Aquilaria sinensis (Lour.) Spreng. (Thymelaeaceae) led to the isolation of a new cucurbitane-type triterpenoid, aquilarolide A (1), along with five known compounds (2-6). The structure of 1 was elucidated by extensive 1D and 2D nuclear magnetic resonance (NMR) experiments and mass spectrometry (MS) data and theoretical calculations of its electronic circular dichroism (ECD) spectra. Aquilarolide A, cucurbitacin E (3), cucurbitacin B (4), and 7-hydroxy-6-methoxy-2-[2-(4-methoxyphenyl)ethyl]-4H-1-benzopyran-4-one (6) showed significant cytotoxicity against human lung adenocarcinoma SPC-A-1, human lung squamous cell carcinoma NCI-H520, human lung adenocarcinoma A549, and paclitaxel-resistant A549 (A549/Taxol) cell lines. All four active compounds, with IC50 values ranging from 0.002 to 0.91 µM, had better inhibitory activities against A549/Taxol cells than paclitaxel (IC50 = 1.80 µM). Among them, cucurbitacin E (IC50 = 0.002 µM) is the most active. Further studies are needed to evaluate their in vivo antitumor activities and to clarify their mechanisms.

Five new 2-(2-phenylethyl)chromone derivatives and three new sesquiterpenoids from the heartwood of Aquilaria sinensis, an aromatic medicine in China.

Five new 2-(2-phenylethyl)chromone derivatives, (5S,6R,7R,8S,7'R)-7'-hydroxyagarotetrol (1), (5S,6R,7R,8S,7'S)-7'-hydroxyagarotetrol (2), (6S,7S,8R)-2­[2­(4-methoxyphenyl)ethyl]­6,7,8­trihydroxy­5,6,7,8­tetrahydrochromone (3), (6S,7S,8R)-2­(2-phenylethyl)­6,7,8­trihydroxy­5,6,7,8­tetrahydrochromone (4), (5S,6R,7S,8R)-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydro-8-[2-(2-phenylethyl)-7-methoxychromonyl-6-oxy]chromone (5), three new sesquiterpenoids, (4S,5S,7S,8S,10S,13R)-7,8,13-trihydroxyrotunda-1,11-dien-3-one (6), (4S,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one (7), and (4R,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one (8), along with 14 known compounds were isolated from the resinous heartwood of Aquilaria sinensis (Thymelaeaceae). The chemical structures of these new compounds were elucidated by 1D and 2D NMR and MS data, single-crystal X-ray diffraction analysis, and electronic circular dichroism (ECD) calculations. The neuroprotective activities of these isolates were evaluated using an in vitro model of rat adrenal pheochromocytoma (PC12) cell injury induced by corticosterone. At concentrations from 5 to 40 µM, compounds 4 and 6, agarotetrol (9), and 6-hydroxy-2-(2-phenylethyl)chromone (17) showed significant protective activities against corticosterone-induced PC12 cell injury (P < 0.001).

Sesquiterpenoids and 2-(2-Phenylethyl)chromone Derivatives from the Resinous Heartwood of Aquilaria sinensis.

One novel spirolactone, aquilarisinolide (1), three new sesquiterpenoids, (2R,4S,5R,7R)-2-hydroxyeremophila-9,11-dien-8-one (2), (1R,4S,5S,7R,11R)-13-hydroxyepidaphnauran-9-en-8-one (3), and (4R,5S,7R,8S,10S,13R)-8,13-dihydroxyrotunda-1,11-dien-3-one (4), together with 13 known compounds (5-17) were isolated from the resinous heartwood of Aquilaria sinensis (Thymelaeaceae). The structures of the new compounds were elucidated based on the analysis of NMR and MS data and theoretical calculations their ECD spectra. The isolated compounds were evaluated for their protective activities against PC12 cell injury induced by corticosterone (CORT) and 1-methyl-4-phenylpyridine ion (MPP+), as well as inhibitory activities against BACE1. Compound 4, 5,6-dihydroxy-2-(2-phenylethyl)chromone (5), daphnauranol B (7), 6-methoxy-2-[2-(3-methyoxyphenyl)ethyl]chromone (10), isoagarotetrol (14), and 1-hydroxy-1,5-diphenylpentan-3-one (16) showed significant protective effects on CORT-induced injury in PC12 cells at a concentration of 20 µM (P < 0.001). Isoagarotetrol (14) showed a significant protective effect on MPP+-induced injury in PC12 cells at a concentration of 20 µM (P < 0.001), while compound 4 showed a moderate activity (P < 0.01). The BACE1-inhibitory activities of all tested compounds were very weak with less than 30% inhibition at a concentration of 20 µM.

Neuroprotective compounds from the resinous heartwood of Aquilaria sinensis.

Six undescribed compounds, including three sesquiterpenoids [(4S,5S,7S,8S,11R)-7-hydroxyguai-1(10)-en-8,12-olide, aquilarisinone, and 2Z,7(13),9E-humulatrien-12-ol-5-one], one diphenylpentanone [1-(2-hydroxyphenyl)-5-phenylpentan-3-one], and two 2-(2-phenylethyl)chromones (6-epiagarotetrol and triepoxyhexahydrochromone A), along with 15 known compounds, were isolated from the resinous heartwood of Aquilaria sinensis (Thymelaeaceae). Their structures were determined by mass (MS) and nuclear magnetic resonance (NMR) spectroscopic data. The absolute configuration of (4S,5S,7S,8S,11R)-7-hydroxyguai-1(10)-en-8,12-olide was confirmed by X-ray diffraction analysis, and the configurations of (4S,7S,8S,10R,11R)-7,10-epoxyguai-1(5)-en-8,12-olide, aquilarisinone, 6-epiagarotetrol, and triepoxyhexahydrochromone A were confirmed by electronic circular dichroism (ECD) calculations. The neuroprotective activities of the compounds were evaluated using models of BACE1 inhibition and PC12 cells with corticosterone- and 1-methyl-4-phenylpyridine ion (MPP+)-induced damage. At concentrations of 1, 2, and 5 µM, triepoxyhexahydrochromone A, (+)-(7R,10R)-selina-4,11(13)-diene-12,15-dial, (-)-(5R,7R,10R)-12,15-dioxo-α-selinene, and (+)-(1R,4S,5R)-1ß-hydroxyeremophila-7(11),9-dien-8-one exerted significant protective effects (p < 0.01) on PC12 cell injury induced by corticosterone, while triepoxyhexahydrochromone A and (-)-(5R,7R,10R)-12,15-dioxo-α-selinene exerted significant protective effects (p < 0.01) on MPP+-induced PC12 cell injury at concentrations of 1, 2, and 5 µM. No compounds produced significant inhibitory effects on BACE1, with inhibition rates of less than 20% observed at a concentration of 20 µM.

Alkaloids from the Branches and Leaves of Elaeocarpus angustifolius.

Nine new alkaloids, (+)-1, (-)-1, 2, (+)-3, (-)-3, and 4-7, along with five known compounds (8-12), were obtained from the branches and leaves of Elaeocarpus angustifolius. The alkaloids were structurally characterized by NMR and MS data. The absolute configurations of (+)-1, (-)-1, (+)-3, and (-)-3 were determined by comparing their experimental and computed electronic circular dichroism spectra. (±)-8,9-Dehydroelaeocarpine (5), (±)-9-epielaeocarpine cis-N-oxide trifluoroacetate (6), and (±)-elaeocarpine trifluoroacetate (9) exerted weak inhibitory activities against butyrylcholinesterase with IC50 values of 39, 29, and 35 µM, respectively, while that of tacrine, the positive control, was 0.07 ± 0.01 µM. This is the first report of the cholinesterase inhibitory activities of Elaeocarpus alkaloids.

Amides, Isoquinoline Alkaloids and Dipeptides from the Aerial Parts of Piper mullesua.

One undescribed amide, pipermullesine A, two undescribed isoquinoline alkaloids, pipermullesines B and C, and six undescribed dipeptides, pipermullamides A-F, along with 28 known compounds, were isolated from the aerial parts of Piper mullesua. The structures of the undescribed compounds were elucidated based on the analysis of 1D and 2D NMR and MS data. Furthermore, the structures of pipermullesines A-C were confirmed by single crystal X-ray diffraction analysis. All isolates were evaluated for inhibitory activity against platelet aggregation induced by thrombin (IIa) or platelet-activating factor (PAF). (-)-Mangochinine, pellitorine, and (2E,4E)-N-isobutyl-2,4-dodecadienamide showed weak inhibitory activity against rabbit platelet aggregation induced by PAF, with IC50 values of 470.3 µg/mL, 614.9 µg/mL, and 579.7 µg/mL, respectively.

Substituting one Paris for another? In vitro cytotoxic and in vivo antitumor activities of Paris forrestii, a substitute of Paris polyphylla var. yunnanensis.

ETHNOPHARMACOLOGICAL RELEVANCE: Chong-lou (Paris polyphylla var. yunnanensis or P. polyphylla var. chinensis) is traditionally used as an anticancer medicine in China. It is also the material basis of some Chinese patent anticancer medicines, such as Gan-Fu-Le capsules, Bo-Er-Ning capsules, Lou-Lian capsules, Ruan-Jian oral liquid, and Qi-Zhen capsules. P. forrestii, a substitute for Chong-lou, is planted at a large scale in the Yunnan Province of China. AIM OF THE STUDY: To clarify the active chemical constituents of P. forrestii and evaluate the in vitro and in vivo anticancer activities of the total saponins from P. forrestii. MATERIALS AND METHODS: The total saponins of P. forrestii were extracted and separated to yield pure compounds by chromatographic techniques, and the structures of the isolates were elucidated by spectroscopic methods. The cytotoxicity of the crude extracts, total saponins, and chemical constituents were evaluated using an MTS assay. In vivo antitumor activities of the total saponins from P. forrestii were measured using H22 tumor-bearing mice by intraperitoneal (ip) administration. RESULTS: Eight compounds, including polyphyllin D (1), formosanin C (2), dioscin (3), diosgenin-3-O-α-l-rhamnopyranosyl-(1→2)-ß-d-glucopyranoside (4), paris saponin H (5), pennogenin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→4)]-ß-d-glucopyranoside (6), pariposide A (7), and crustecdysone (8), were isolated from the total saponins of P. forrestii. The total saponins and compounds 1-6 showed significant inhibitory activity against the growth of the HL-60, SMMC-7721, A-549, MCF-7, and SW480 cell lines. The total saponins from P. forrestii had a tumor-inhibitory effect in H22 tumor-bearing mice upon ip (2.25 mg/kg dose) administration, with an inhibition rate of 42.6% compared with cisplatin (ip, 2 mg/kg dose, 53.9% inhibition rate). CONCLUSION: The results support that P. forrestii could be a substitute for P. polyphylla var. yunnanensis as an anticancer medicine.

New aporphine alkaloids from the aerial parts of Piper semiimmersum §.

Two new aporphine alkaloids, semiimmersumines A (1) and B (2), along with 20 known compounds, were isolated from the aerial parts of Piper semiimmersum (Piperaceae). The structures of the new compounds were elucidated based on the analysis of 1D and 2D NMR, MS, and CD data. The absolute configuration of semiimmersumine A (1) was determined by single crystal X-ray diffraction analysis using anomalous dispersion with copper radiation. The effects of all compounds from the plant on rabbit platelet aggregation induced by thrombin (IIa) or PAF were also evaluated.

Amides and neolignans from the aerial parts of Piper bonii.

Six amides, piperbonamides A-F, three neolignans piperbonins A-C, and 11 known compounds were isolated from the aerial parts of Piper bonii (Piperaceae). The structures of piperbonamides A-F and piperbonins A-C were elucidated based on the analysis of 1D and 2D NMR and MS data. Piperbonin A, (+)-trans-acuminatin, (+)-cis-acuminatin, (+)-kadsurenone, and pipernonaline showed weak activity against platelet aggregation with IC50 values of 118.2, 108.5, 90.02, 107.3, and 116.3 µM, respectively, as compared with the positive control, tirofiban, with an IC50 value of 5.24 µM. Piperbonamides A-F were inactive against five tumor cell lines at concentrations up to 40 µM.

Sarmentosumols A to F, new mono- and dimeric alkenylphenols from Piper sarmentosum.

Two new mono- and four new dimeric alkenylphenols, namely sarmentosumols A to F (1-6), were isolated from the aerial parts of Piper sarmentosum. The structures of these compounds were determined through a detailed analysis of NMR and MS data. Their antimicrobial activity against Escherichia coli, Staphyloccocus aureus, and Candida albicans, and their cytotoxic activity against human myeloid leukemia (K562) and human lung adenocarcinoma (A549) cell lines were also evaluated. Except for sarmentosumol A (1), whose MIC on S. aureus was reported to be 7.0 µg/mL, none of the other newly discovered compounds exhibited antimicrobial property. The studied compounds did not possess any cytotoxic property.

Palhinine A, a novel alkaloid from Palhinhaea cernua.

Palhinine A, a novel C(16)N-type Lycopodium alkaloid with a unique 5/6/6/9 tetracyclic ring system, was isolated from the whole plant of Palhinhaea cernua L. (Lycopodiaceae). Its structure was elucidated by spectroscopic methods, and the absolute configuration was determined by single-crystal X-ray diffraction analysis using the Flack parameter. Palhinine A is reported as the first example of Lycopodium alkaloids of which C-16 is fused to a new ring through a C-16-C-4 lingkage.

Clerodane diterpenoids and prenylated flavonoids from Dodonaea viscosa.

Repeated column chromatography of the EtOAc-soluble fraction of the aerial parts of Dodonaea viscosa led to the isolation of two new modified clerodanes, methyl dodovisate A (1) and methyl dodovisate B (2), two new prenylated flavonoids, 5,7,4'-trihydroxy-3',5'-di(3-methylbut-2-enyl)-3,6-dimethoxyflavone (10) and 5,7,4'-trihydroxy-3'-(4-hydroxy-3-methylbutyl)-5'-(3-methylbut-2-enyl)-3,6-dimethoxyflavone (11), together with eight known compounds, dodonic acid (3), hautriwaic acid (4), hautriwaic lactone (5), (+)-hardwickiic acid (6), 5alpha-hydroxy-1,2-dehydro-5,10-dihydroprintzianic acid methyl ester (7), strictic acid (8), dodonolide (9), and aliarin (12). The structures of the new compounds were elucidated by spectroscopic data analysis. Compounds 1-9 and 11 were evaluated on larvicidal activity against the fourth-instar larvae of Aedes albopictus and Culex pipens quinquefasciatus.