Xi-Kui Liu

Three new hecogenin glycosides from fermented leaves of Agave americana

Eight steroidal compounds, including three new hecogenin glycosides, agamenosides D–F, were isolated from the fermented leaves of Agave americana. The structures of the new steroidal saponins were elucidated by spectroscopic data and chemical methods. The activity of the isolated compounds on deformations of mycelia germinated from conidia of Pyricularia oaryzae P-2b was evaluated.

Steroidal saponins and cytoxicity of the wild edible vegetable - Smilacina atropurpurea.

Four new steroidal saponins, smilacinoside A (1), B (2), C (3), and D (4), together with three known saponins, funkioside D (5), aspidistrin (6) and 26-O-beta-d-glucopyranosyl-22-methoxyl-(25R)-furost-5-en-3beta,26-diol 3-O-beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranosyl-(1-->4)-beta-d-galactopyranoside (7) were isolated from the dried tender aerial parts of Smilacina atropurpurea (Franch.) Wang et Tang. The structures of new compounds were elucidated as diosgenin 3-O-alpha-l-rhamnopyranosyl-(1-->2)-O-beta-d-galactopyranoside (1), diosgenin 3-O-alpha-l-rhamnopyranosyl-(1-->3)-[6-O-palmitoxyl]-O-beta-d-galactopyranoside (2), 26-O-beta-d-glucopyranosyl-(25R)-furost-5-en-3beta,22xi,26-triol 3-O-alpha-l-rhamnopyranosyl-(1-->2)}-beta-d-galactopyranoside (3) and 26-O-beta-d-glucopyranosyl-22-methoxyl-(25R)-furost-5-en-3beta,26-diol 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-galactopyranoside (4) on the basis of chemical methods and detailed spectroscopic analysis, including 1D and 2D NMR techniques and single-crystal X-ray diffraction, respectively. Six of these compounds and MeOH extract were tested for their in vitro cytotoxicity toward K562 human tumor cells by an improved MTT method. Smilacinoside A, funkioside D and aspidistrin exhibited significant in vitro cytotoxicity against K562 with IC(50) values of 1.09, 2.93 and 0.47microg/mL, respectively.

Microbial transformation of diosgenin by filamentous fungus Cunninghamella echinulata

Microbial transformation of diosgenin (1) by suspended-cell cultures of the filamentous fungus Cunninghamella echinulata CGMCC 3.2000 was investigated. Incubation of the substrate diosgenin (1) with this fungus led to the isolation of three products: two known compounds, (25R)-spirost-5-en-3β,7β,12β-triol (2) and (25R)-spirost-5-en-3β,7β,11α-triol (3), and a new compound (25R)-spirost-5-en-3β,7α,11α-triol (4). The structural elucidations of the three compounds were achieved mainly by the MS, 1D and 2D NMR spectroscopic methods and comparison with known compounds. C. echinulata CGMCC 3.2000 has not been used before in the biotransformation of diosgenin (1).

Four new oleanane type Saponins from Morina nepalensis var. alba

Four new oleanane type saponins, monepalosides G–J (1–4), were isolated from the water-soluble part of the whole plant of Morina nepalensis var. alba Hand-Mazz. On the basis of chemical and spectroscopic evidence, their structures were determined as 3-O-α-L-arabinopyranosyl-(1→3)-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside G, 1), 3-O-α-L-arabinopyranosyl-(1→3)-β-D-xylopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside H, 2), 3-O-α-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside I, 3), 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosy-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside J, 4), respectively. Two-dimensional NMR spectra, including H–H COSY, HMQC, 2D HMQC–TOCSY, HMBC and ROESY were utilized in the structure elucidation and complete assignments of 1H and 13C NMR spectra.

A new ergostanol saponin from Dioscorea deltoidea Wall var. orbiculata

From the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata , a novel ergostanol saponin, orbiculatoside A ( 1 ), was isolated and identified as 3- O - g - d -glucopyranosyl-ergost-5-ene-3 g , 26-diol-26- O - g - d -glucopyranosyl(1 M 3)-[ g - d -glucopyranosyl(1 M 2)- g - d -glucupyranosyl(1 M 6)]- g - d -glucopyranoside by various NMR techniques in combination with chemical methods. The new saponin showed strong activity against Pyricularia oryzae , with a MMDC (minimum morphological deformation concentration) value of 28.04 w mol/l and was cytotoxic to cancer cell line K562, HCT-15, A549, HT1080, and A2780a in vitro .

Five new indole alkaloids from the leaves of Rauvolfia yunnanensis

Five new indole alkaloids, rauvoloids A-E (1-5), together with two known ones, raucaffrinoline (6) and perakine (7) were isolated from the leaves of Rauvolfia yunnanensis. Their structures were elucidated by extensive spectroscopic methods. Structurally, rauvoloids A (1), B-C (2-3) and D (4) with unusual substitution patterns (no substitution, Cl and (1E)-3-oxo-butenyl, respectively) at C-20, are the first examples of perakine-type alkaloids with C18 and C22 skeletons.

Anticancer Activity of Tirucallane Triterpenoids from Amoora dasyclada

A new tetranortriterpene 3α-acetoxy-24,25,26,27-tetranortirucalla-7-ene-23(21)-lactone (3), and eleven other compounds were isolated from the twigs of Amoora dasyclada. The structure of compound 3 was identified on the basis of spectroscopic data, and the bioactive experiments of 1 and 3-5 against AGZY 83-a (human lung cancer cells) and SMMC-7721 (human liver cancer cells) are documented. Among them, compound 5 exhibited a strong activity against SMMC-7721.

Anticancer Activity of Diterpenoids from Amoora ouangliensis and Amoora stellato-squamosa

A new ent-halimane-type diterpene, named 5(10),14-ent-halimadien-3β,13S-diol (1), was isolated from the bark of Amoora ouangliensis and its chemical structure determined on the basis of spectroscopic analysis. Additionally, ten other diterpenoids were obtained from A. ouangliensis and A. stellato-squamosa. The bioactive experiments of all compounds against AGZY 83-a (human lung cancer cells) and SMMC-7721 (human liver cancer cells) cells were documented.