Two new norisoprenoid derivatives from the red alga Gymnogongrus flabelliformis

Two new norisoprenoid derivatives have been isolated from the red alga Gymnogongrus flabelliformis. Their structures were elucidated as (3R, 6R, 7E)-(+)-3-O-phenylacetyl-4,7-megastigmadiene-9-one and (3R,7E)-(-)-3-O-phenylacetyl-5,7-megastigmadiene-9-one, respectively, by spectroscopic methods including HRMS, 1D and 2D NMR techniques.

A New Triterpenoid from Amoora dasyclada

Five compounds were isolated from the EtOH extraction of the stem of Amoora dasyclada (How et T. Chen) C. Y. Wu (Meliaceae). On the basis of spectroscopic methods, their structures were elucidated as 24, 25-epoxy-tirucall-7-ene-3, 23-dione (1), 24, 25, 26, 27-tetranortirucall-7-ene-3-oxo-23(21)-lactone (2), taraxerone (3), taraxerol (4) and b-sitosterol (5). Among them, compound 1 was a new triterpenoid, compounds 3-5 were firstly obtained from this plant; compound 2, an tetranortriterpenoid, was firstly isolated from natural sources, and its NMR data were assigned for the first time. Moreover, the D7-bond and the Me-14 in compound 2 were never changed, which has never been found in other tetranortriterpenoids. And the biosynthetic pathway of tetranortriterpenoid was further discussed.

Two new diterpenes from Euphorbia kansuensis

Two new lathyrane diterpenes, 3 beta,5 alpha-dihydroxy-15 beta-cinnamonyloxy-14-oxoladiyra-6Z, 12E- diene (1) and 3 beta,5 alpha,20-trihydroxy-15 beta-cinnamoyloxy-14-oxolathyra-6Z, 12E-diene (2), were isolated from the roots of Euphorbia kansuensis. Their structures were determined by spectroscopic methods. (C) 2008 Elsevier B.V. All rights reserved.

A new guaiane diterpenoid from Euphorbia wallichi

A new guaiane-type diterpenoid, (1 alpha, 5 alpha, 7 alpha)-3,10(18), 11-dictytriene-19-acid, was obtained from the roots of Euphorbia wallichii. This is the first isolation of guaiane diterpene from this genus of Euphorbia. The structure was elucidated by spectral methods. And the compound was tested for the cytotoxicities on the cancer cell line P-388 and A-549 in vitro.

Two new xanthone glycosides from Swertia tetraptera

Two new xanthone glycosides, tetraswerosides A and B, were isolated from the whole plant of Swertia tertraptera. Their structures were determined as 3-O-beta -D-glucopyranosyl-1-hydroxy-4,7-dimethoxyxanthone and 3-O-[beta -D-xylopyranosyl-(1-->6)-beta -D-glucopyranosyl]-1- hydroxy-4,7-dimethoxyxanthone by spectroscopic methods.

A new method for determination of adsorption and desorption coefficients of pesticides with soil column liquid chromatography

The adsorption and desorption coefficients of atrazine, methiocarb and simazine on a sandy loam soil were measured in this study with soil column liquid chromatographic (SCLC) technique. The adsorption and desorption data of all the three pesticides followed Freundlich isotherms revealing the existence of hysteresis. In comparing with other methods, SCLC method showed some characteristics such as rapidity, online and accuracy.

Two new iridoid glycosides from the Tibetan folk medicine Swertia franchetiana

Two new iridoid glycosides designated as senburiside III (2) and senburiside IV (3), together with one known iridoid glycoside senburiside I (1) and three known secoiridoid glucosides swertiamarin (4), gentiopicroside (5) and sweroside (6), were isolated from the whole plant of Swertia franchetiana. The structures of the two new compounds were elucidated by spectroscopic methods.