A new bioactive prenylated dihydroflavanoid from Dolichos tenuicaulis （Baker） Craib

A new prenylated dihydroflavonoid was obtained from the root of Dolichos tenuicaulis （Baker） Craib. The structure was elucidated as （2S）-5,2＇,6＇-trihydroxy-3＇″, 8-di （γ,γ-dimethyl-allyl）-2＇″, 2＇″-dimethylpyrano-[5＇″,6＇″： 6,7]-2＇″″,4＇″″-cyclohexadiene-1 ＇″″-one-[2＇″″,3＇″″： 3＇,4＇]-flavanone, named dolichnin A, by spectroscopic methods including UV, IR, HR-EI-MS, 1D NMR and 2D NMR techniques, and subsequently, the anticancer activity of this compound to inhibit human cancer cells＇ growth including A549, BEL-7402, Hep-3B, SMMC7721, HT-29, MCF-7, SGC-7902, K562, A498 and PC3 cell lines by MTT method was evaluated in vitro.     

A new iridoid from Guettarda grazielae M.R.V. Barbosa (Rubiaceae)

Chromatographic fractionation of the chloroform extracts from the stem bark and stems of Guettarda grazielae resulted in the isolation of a new iridoid (guettardodiol, 1) and the secoiridoid sarracenin (2), described for the first time in this genus. The structural elucidation of these compounds was based on spectroscopic analyses (IR, MS as well as 1-D and 2-D NMR experiments).     

A new furostanol saponin from Dendrobium chrysanthum Lindl. with cytotoxic activity

A new furostanol saponin, (25R)-26-O-(α-d-glucopyranosyl)-(1→2)-α-l-rhamnopyranosyl-furost-5-ene-3β, 22α, 26-triol-3-O-α-d-glucopyranoside (1), together with four known compounds 2–5 were isolated from the ethanolic extract of the stems of Dendrobium chrysanthum Lindl. The structures of these new compounds were identified by extensive spectroscopic analysis including 1D and 2D NMR and HR-ESI-MS, as well as chemical methods. Compounds 1–3 were isolated from D. chrysanthum for the first time. Furthermore, the inhibitory effects of the compounds on tumor cells were evaluated, and compounds 1–2 exhibited significant cytotoxic activities potentially against SPC-A1, MCF-7 and HeLa human cancer cell lines. Compounds 3–5 showed inhibitory activity against the SPC-A1 and MCF-7.     

4-dehydroxyepisarcovagine A,a new steroidal alkaloid from Sarcococca pruniformis Lindl.

A new steroidal alkaloid, 4-dehydroxyepisarcovagine A (1), along with seven known alkaloids, sarcovagine D (2), sarcovagenine C (3), epoxysarcovagenine D (4), Pachysamine L (5), Pachysamine E (6), sarcovagine A (7) and sarcovagine B (8), was isolated from the roots and stems of Sarcococca pruniformis Lindl. The structure of compound 1 was elucidated by means of spectroscopic analysis.     

A new naphthopyrone from the root of Pleuropterus ciliinervis

A new naphthopyrone, pleuropyrone A (1), together with (-)-lyoniresinol 3a-O-beta-D-glucopyranoside (2) and (+)-lyoniresinol 3a-O-beta-D-glucopyranoside (3) was isolated from the roots of Pleuropterus ciliinervis. The structure of pleuropyrone A (1) was determined to be 2,5-dimethyl-8-hydroxynaphthopyrone 10-O-beta-D-glucopyranoside by spectroscopic methods including 2D-NMR. Compounds 2 and 3 showed moderate antioxidant activity.     

A new enzymatic approach to (R)-Tamsulosin hydrochloride

An enantioselective baker’s yeast mediated approach to the pharmacologically active (R)-enantiomer of Tamsulosin hydrochloride is reported.     

A novel bacteriohopanoid from Celtis australis L.bark

A novel bacteriohopanoid elucidated as 3β-hydroxy-35-(cyclohexyl-5’-propan-7’-one)-33-ethyl-34-methyl-bactereohopane(1) has been isolated from the bark of Celtis australis(Ulmaceae) together with three known compounds apigenin,quercetin and its glucoside.The structure of 1 was characterized by means of chemical and spectral methods including advanced 2D NMR studies.     

A new and short enantioselective synthesis of (R)-pantolactone

Dihydro-4,4-dimethyl-2(3H)-furanone 6, the key intermediate to (R)-pantolactone 2, has been synthesized in two steps via the radical cyclization of bromoether 5. Silyl enol ether 7, prepared from 6, on Sharpless asymmetric dihydroxylation gave (R)-pantolactone 2 in moderate yield and excellent enantioselectivity.     

A new approach for asymmetric synthesis of (R)-3-methylpyrrolidine alkaloids from (S)-malic acid

Diastereoselective methylation of dimethyl (S)-malate 7, followed by two, three-step reductive de-hydroxylation procedures afforded dimethyl (R)-2-methylsuccinate 11 in 80.2% e.e. and 84.7% e.e., respectively. The latter compound was further transformed into the natural enantiomers of the ant venom alkaloids (R)-leptothoracine 1 and (R)-3-methyl-N-(2-phenylethyl)-pyrrolidine 2.     

A new asymmetric synthesis of the anti-tumor alkaloid (R)-(+)-crispine A

We report a novel, facile, and asymmetric approach for the synthesis of the anti-tumor alkaloid (+)-crispine A via a highly diastereoselective N-acyliminium cyclization reaction as a key synthetic step.     

Studies on the constituents of Gentiana species. II. A new triterpenoid,and (S)-(+)- and (R)-(-)-gentiolactones from Gentiana lutea

A new triterpenoid, 12-ursene-3beta, 11alpha-diol 3-O-palmitate (1), has been isolated from the rhizomes and roots of Gentiana lutea, together with the artificial diene derivative, 9 (11), 12-ursadien-3beta-ol 3-O-palmitate (1a) and five known compounds (3-7). Their structures were established on the basis of spectral analysis. In addition, (+/-)-gentiolactone [(+/-)-2], isolated from this plant, was successfully separated into its enantiomers [(+)-2, (-)-2] for the first time, and the absolute configurations at C-9 of (+)-2, (-)-2 were assigned as S and R, respectively, from the optical rotations and the circular dichroism (CD) spectral data.     

A new alkylbenzoquinone from Embelia rowlandii Gilg. (Myrsinaceae)

A new alkylbenzoquinone named embeliquinone (1) together with five known compounds, lupeol (2), 3-O-[6′-O-palmitoyl-β-d-glucosyl]-spinasta-7,22(23)-diene (3), quercetin (4), (2S,3S,4R,8E)-2-[(2′R)-2′-hydroxy-heneicosanoylamino]-heneicosane-1,3,4-triol-8-ene (5), and β-sitosterol-3-O-β-d-glucopyranoside (6) were isolated from the MeOH leaf extract of Embelia rowlandii by using repeated open column chromatography techniques. The structure of the new compound was characterized by analyses of 1D- and 2D-NMR, and MS data. Embeliquinone (1) had moderate anti-cell proliferation activity against A549 cell line with the IC₅₀ value of 21.8 μM. In addition, 1 exhibited weak antibacterial activities against Klebsiella pneumoniae and Staphylococcus aureus with an MIC value of 206.0 μM in both cases.     

A new ent-kaurane diterpene derivative from the stems of Eurya chinensis R.Br

One new ent-kaurane diterpene derivative (1), along with four known diterpenes, was isolated from the stems of Eurya chinensis R.Br. The structure of the new compound was established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 1 showed moderate anti-inflammatory activities with IC₅₀ value of 8.12 μM. This is the first example of diterpenoids with 4-hydroxy-4-(2-hydroxyethyl)-1-hydroxyl-cyclohexanoyl substituent.