Unprecedented Quassinoids with Promising Biological Activity from Harrisonia perforata.

Perforalactone A (1), a new 20S quassinoid with a unique cagelike 2,4-dioxaadamantane ring system and a migrated side chain, was isolated from the plant Harrisonia perforata together with two biosynthetically related new quassinoids. The structures of these natural products were elucidated by NMR spectroscopy, X-ray diffraction analysis, computational modeling, and the CD excitation chirality method. The compounds exhibited notable biological properties, including insecticidal activity against Aphis medicaginis Koch and antagonist activity at the nicotinic acetylcholine receptor of Drosophila melanogaster. The structural features of these compounds may be related to their promising biological characteristics. Their biosynthesis and an alternative origin of quassinoid-type natural products are also discussed.

Camellisins A-C, three new triterpenoids from the roots of Camellia sinensis.

Eighteen compounds, including three new triterpenoids, camellisins A-C (1-3), were isolated from the roots of Camellia sinensis. Their structures were determined on the basis of detailed spectroscopic analysis.

Tetranortriterpenoids from the Leaves of Cipadessa cinerascens.

Seven known and six new tetranortriterpenoids, cineracipadesins A-F (1-6), were isolated from the leaves of Cipadessa cinerascens. Compound 1 has a mexicanolide-type structural skeleton with a rare 9alpha,11alpha-epoxide ring; compound 2 has a methyl angolensate-type structure with 9,11-dihydroxy groups, representing the first example of a precursor of a trijugin-type limonoid; and 3 is the first reported methyl angolensate-type limonoid with a ketone group at ring C. Their structures were determined with extensive spectroscopic analysis. X-ray crystallography confirmed the structure of 1. The ability of compounds 1-7 to inhibit the growth of the P-388 murine leukemia cell line was evaluated.

Novel coumarin and furan from the roots of Angelica pubescens f. biserrata.

A new natural coumarin, angepubebisin (1), and a new furan, angepubefurin (2), together with the five known compounds, umbelliferone, angelol B (3), ulopterol (4), peucedanol (5), and scopoletin, were isolated from the roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan. The structures of angepubebisin (1) and known compounds were determined by spectroscopic methods, including IR, UV, EI-MS, HR-FTICR-MS, 1D-, and 2D-NMR spectral analyses, and angepubefurin (2) was determined by HR-FTICR-MS and X-ray diffraction analyses.

Nortriterpenoids and lignans from Schisandra sphenanthera.

Nortriterpenoids, sphenadilactone C (1) and sphenasin A (2), together with four known lignans (3-6), were isolated from the leaves and stems of Schisandra sphenanthera. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and compound 2 was further confirmed by single-crystal X-ray diffraction. Compound 1 features a partial enol moiety and an acetamide group in its structure. In addition, compounds 1, 3-6 showed weak anti-HIV-1 activity with EC(50) values in the range of 15.5-29.5 microg/mL.

Three new C21-steroidal glycosides from the roots of Cynanchum inamoenum.

Three new C(21)-steroidal glycosides presenting an unusual 13,14:14,15-disecopregnane-type skeleton, named inamosides A-C (1-3), together with two known C(21)-steroidal glycosides, were isolated from the MeOH extract of the roots of Cynanchum inamoeum (Maxim.) Loes (Asclepiadaceae). The aglycone of compounds 1, 2, and 3 has a 2beta-hydroxyl, which has not yet been reported in the literature. The structure and relative configuration of the aglycone of compounds 1, 2, and 3 were established by X-ray crystallographic analysis.

Benzylphenethylamine alkaloids from Hosta plantaginea with inhibitory activity against tobacco mosaic virus and acetylcholinesterase.

Five new benzylphenethylamine alkaloids, hostasine (1), 8-demethoxyhostasine, 8-demethoxy-10-O-methylhostasine, 10-O-methylhostasine, and 9-O-demethyl-7-O-methyllycorenine, along with 12 known compounds, were isolated from Hosta plantaginea by bioassay-guided fractionation. The structures of the new alkaloids were established by means of extensive spectroscopic methods, and the relative configuration of 1 was further confirmed by single-crystal X-ray diffraction. 7-Deoxy-trans-dihydronarciclasine (IC(50) = 1.80 microM), a known alkaloid, showed strong activity against tobacco mosaic virus by the half-leaf method. Some of these alkaloids were also evaluated for their inhibitory activity against acetylcholinesterase. 8-Demethoxy-10-O-methylhostasine was found to possess significant activity, with an IC(50) of 2.32 microM.

Two new sesquiterpenes from Alisma orientalis.

Two new sesquiterpenoids named alismorientols A (1) and B (2) were isolated from the rhizomes of Alisma orientalis collected in Sichuan province, People's Republic of China. Their structures were elucidated based on spectroscopic analyses (1D and 2D NMR data including HSQC, HMBC, COSY, and ROESY) and X-ray crystallographic analysis. Anti-hepatitis B virus (HBV) bioassay revealed that compound 1 showed moderate anti-HBV activity in vitro with IC50 for HBsAg: 1.1 microM, for HBeAg: 14.7 microM.

Isolation and characterization of biogenetically related highly oxygenated nortriterpenoids from Schisandra chinensis.

Pre-schisanartanin (1) and schindilactones A-C (2-4) were isolated from Schisandra chinensis. Among them, compound 1 had an unprecedented carbon skeleton. More importantly, the structure features of this compound provided new insight into the biosynthesis of triterpenoids with schisanartane skeleton. Their structures were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, and on the basis of the absolute structure of one related nortriterpenoid (5), which was determined for the first time by a modified Mosher method.

Wuweizidilactones A-F: novel highly oxygenated nortriterpenoids with unusual skeletons isolated from Schisandra chinensis.

A phytochemical study of secondary metabolites produced by Schisandra chinensis has led to the isolation of six novel highly oxygenated nortriterpenoids, wuweizidilactones A-F (1-6). Compounds 3-6 possess an unprecedented 3,4-seco-18(13-->14)-abeo-artane skeleton. Interestingly, structures 3-6 have a beta-oriented methyl group at the C-14 position. This structural feature corroborates the biogenetic pathway proposed for the formation of 18-norschiartane-type compounds 1 and 2. The structures of these novel metabolites were established on the basis of their detailed spectroscopic analysis. The structure of 1 was also confirmed by single-crystal X-ray diffraction analysis. For the first time, the absolute configuration of these nortriterpenoids was determined by using a modified Mosher method.

Taxoids from Taxus chinensis.

Two new taxoids, 13,15-epoxy-13-epi-taxayunnasin A (1) and taxchinin N (2), were isolated from the leaves and stems of Taxus chinensis. Compound 2 is the first taxoid to be reported with an alpha,beta-unsaturated lactone at C-4, C-5, C-20, and C-2. The structure of 1 was elucidated by spectroscopic analysis and confirmed by semisynthesis from taxayunnasin A, while 2 was determined structurally using spectroscopic methods and by single-crystal X-ray diffraction.

Five new steroidal compounds from Ypsilandra thibetica.

Five new steroids, including the four new steroidal saponins ypsilandroside B (1), ypsilandroside A (2), isoypsilandroside A (4), and isoypsilandroside B (5), as well as the new steroidal sapogenin isoypsilandrogenin (3), were isolated from the whole plant of Ypsilandra thibetica Franch. Their structures were determined on the basis of spectroscopic analyses, including extensive 2D-NMR techniques. The structure and relative configuration of ypsilandroside B (=(3beta,12alpha,25R)-3-[(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-apiofuranosyl)oxy]spirost-5-ene-12,27-diol; 1) was unequivocally determined by single-crystal X-ray diffraction. The antifungal and antibacterial activities of 1-5 towards various types of fungi and bacteria are reported.

Nortriterpenoids from Schisandra lancifolia.

Six new nortriterpenoids, lancifodilactones I-N (1-6), as well as nine known ones, were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated on the basis of spectroscopic methods including 2D NMR analysis, and the structures of compounds 1 and 4 were further confirmed by single-crystal X-ray crystallography. In addition, all new compounds were tested for anti-HIV-1 activity.

Dichotomains A and B: two new highly oxygenated phenolic derivatives from Dicranopteris dichotoma.

[structure: see text] Dichotomains A (1) and B (2), two new highly oxygenated phenolic derivatives that feature a spirodilactone moiety in their structures, were isolated from the fronds of Dicranopteris dichotoma. Their structures were elucidated on the basis of NMR and MS spectroscopic data, and the stereochemistry of 1 was finally determined by single-crystal X-ray diffraction. Compound 2 showed weak anti-HIV-1 activity.

Sphenadilactones A and B, two novel nortriterpenoids from Schisandra sphenanthera.

[structure: see text] Two novel nortriterpenoid compounds, sphenadilactones A (1) and B (2), have been isolated from the leaves and stems of Schisandrasphenanthera. The structural elucidation of 1 and 2 was accomplished by extensive NMR analysis. The relative stereochemistry of 1 was established by single-crystal X-ray crystallography. Both compounds were tested for their cytotoxicities against K562, A549, and HT-29, and compound 1 was further tested for its anti-HIV-1 activity.

Triterpenoids from Schisandra lancifolia with anti-HIV-1 activity.

A new trinorcycloartane triterpenoid, lancifodilactone H (1), and a new A ring-secocycloartane triterpenoid, lancifoic acid A (2), together with a known compound, nigranoic acid (3), were isolated from the leaves and stems of Schisandra lancifolia. Their structures were elucidated by spectroscopic data analysis. Compound 1 features a biosynthetically modified seven-membered lactone ring, which was confirmed by single-crystal X-ray diffraction. Compounds 1-3 exhibited weak anti-HIV-1 activity in vitro.

Rubriflordilactones A and B, two novel bisnortriterpenoids from Schisandra rubriflora and their biological activities.

Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on the basis of extensive spectroscopic methods, including two-dimensional NMR techniques, and confirmed by X-ray crystallographic analysis. Compound 1 showed weak anti-HIV-1 activity, and compound 2 exhibited an EC50 value of 9.75 microg/mL (SI=12.39) against HIV-1 replication with low cytotoxicity.

[A new hetisine-type alkaloid from the stems and leaves of Aconitum coreanum].

AIM: To study the chemical constituents of the stems and leaves of Aconitum coreanum (Lèvl.) Rapaics. METHODS: The constituents of Aconitum coreanum were isolated by using various kinds of modern chromatographic methods. The new alkaloid was identified on the basis of spectral analysis. RESULTS: Two compounds were isolated and identified as: 13-dehydro-1beta-acetyl-2alpha,6beta-dihydroxyhetisine (I) and Guanfu base G (II). CONCLUSION: Compound I is a new alkaloid.

Kadlongilactones A and B, two novel triterpene dilactones from Kadsura longipedunculata possessing a unique skeleton.

[structure: see text] Two novel triterpene dilactones with an unprecedented rearranged hexacyclic skeleton, kadlongilactones A (1) and B (2), have been isolated from the leaves and stems of Kadsura longipedunculata Finet et Gagnep (Schisandraceae). Their structures were established by comprehensive 1D and 2D NMR spectroscopic analysis, coupled with single-crystal X-ray crystallographic diffraction. Compounds 1 and 2 exerted significant inhibitory effects against human tumor K562 cells with IC(50) = 1.40 and 1.71 microg/mL, respectively.