New amide alkaloids from Piper longum fruits

Three new amide alkaloids piperlongumamides A-C(1-3),together with 12 known ones(4-15),were isolated from the fruits of Piper longum.The structures of the new isolates were determined using spectroscopic data analyses.Cytotoxic activity of these amides against HL-60(human leukemia),A-549(human lung cancer),MCF-7(human breast cancer),SMMC-7721(human liver cancer)and SW480(human rectal cancer)cell lines were evaluated.Piperchabamide B(11)exhibited weak inhibitory activity against HL-60(IC_(50)=21.32μM),A-549(IC_(50)=23.82μM)and MCF-7(IC_(50)=16.58μM)cell lines.

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

One undescribedamide,pipermullesine A,twoundescribed isoquinoline alkaloids,pipermullesinesBand 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–Cwere 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 IC_(50)values of 470.3μg/mL,614.9μg/mL,and 579.7μg/mL,respectively.

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,7ʹR)-7ʹ-hydroxyagarotetrol(1),(5S,6R,7R,8S,7ʹS)-7ʹ-hydroxyagarotetrol(2),(6S,7S,8R)-2-[2-(4-methoxyphenyl)ethyl]-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(3),(6S,7S,8R)-2-(2-phenylethyl)-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(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 40μM,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).

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.(Thyme-laeaceae)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 IC_(50) values ranging from 0.002 to 0.91μM,had better inhibitory activities against A549/Taxol cells than paclitaxel(IC_(50)=1.80μM).Among them,cucurbitacin E(IC_(50)=0.002μM)is the most active.Further studies are needed to evaluate their in vivo antitumor activities and to clarify their mechanisms.