Accuracy mass screening and identification of phenolic compounds from the five parts of Abutilon theophrasti Medic. by reverse-phase high-performance liquid chromatography-electrospray ionization-quadrupoles-time of flight-mass spectrometry

A rapid and resolutive reverse-phase high-performance liquid chromatography-electrospray ionization-quadrupoles-time of flight-mass spectrometry method was established for the screening and identification of the phenolic compounds in the 70% ethanolic extracts from the five parts (roots, stems, leaves, seeds, and exocarps) of Abutilon theophrasti Medic.. Separation and detection conditions were optimized by using a 22 mixing standard, which included phenolic acids, flavonoids and a naphthalene compound. Optimum LC separation was achieved on a C(18) analytical column (250 mm x 4.6 mm id, 5 μm) by gradient elution with water containing 0.1% v/v formic acid (pH 2.4) and acetonitrile as mobile phases, at a flow rate of 1.0 mL/min. The developed method was applied to the study on the constituents of A. theophrasti Medic., and 16 compounds were unequivocally identified with standards. Meanwhile, 37 constituents were tentatively identified by comparing with references. In addition, accurate molecular formulae were conjectured for unknown compounds. To our knowledge, little is known about how these compounds are distributed in A. theophrasti Medic.. Hence, it is clear that the comprehensive analysis of the phenolic compounds of A. theophrasti Medic. is helpful for the quality control and understanding the usage and function of the herb and its products.     

Structure determination of new steroids from Abutilon pakistanicum by NMR techniques

Two new steroids provisionally named as pakisteroid-A (1) and pakisteroid-B (2) have been isolated in crystalline form from Abutilon pakistanicum. Their structures have been assigned as 3-O-beta-D-glucopyranosyl-stigmasta-5,11(12)-diene (1) and 24beta-ethylcholesta-5, 9(11), 22E-trien-3beta-benzoate (2), respectively through extensive NMR studies.     

Structural determination of abutilins A and B,new flavonoids from Abutilon pakistanicum,by 1D and 2D NMR spectroscopy

Two new flavonoids, abutilin A and B, were isolated from the chloroform soluble fraction of Abutilon pakistanicum and their structures assigned from ¹H and ¹³C NMR spectra, DEPT and by 2D COSY, HMQC and HMBC experiments. Ferulic acid (3), (E)‐cinnamic acid (4), 5‐hydroxy‐4′,6,7,8‐tetramethoxyflavone (5), kaempferol (6), luteolin (7) and luteolin 7‐O‐β‐D ‐glucopyranoside (8) have also been reported from this species. Copyright © 2009 John Wiley & Sons, Ltd.     

Cytotoxic constituents of Abutilon indicum leaves against U87MG human glioblastoma cells

The study was aimed to identify cytotoxic leads from Abutilon indicum leaves for treating glioblastoma. The petroleum ether extract, methanol extract (AIM), chloroform and ethyl acetate sub-fractions (AIM-C and AIM-E, respectively) prepared from AIM were tested for cytotoxicity on U87MG human glioblastoma cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. These extracts exhibited considerable activity (IC₅₀ values of 42.6–64.5 μg/mL). The most active AIM-C fraction was repeatedly chromatographed to yield four known compounds, methyl trans-p-coumarate (1), methyl caffeate (2), syringic acid (3) and pinellic acid (4). Cell viability assay of 1–4 against U87MG cells indicated 2 as most active (IC₅₀ value of 8.2 μg/mL), whereas the other three compounds were much less active. Interestingly, compounds 1–4 were non-toxic towards normal human cells (HEK-293). The content of 2 in AIM-C was estimated as 3% by HPLC. Hence, presence of some more active substances besides methyl caffeate (2) in AIM-C is anticipated.     

New Glycosidic Constituents of Abutilon pakistanicum

Pakisides A and B ( 1 and 2 , resp.), new catalpol‐type iridoid glycosides, and a new glycoside, 3 , of scutellarein have been isolated from the AcOEt‐soluble fraction of the whole plant of Abutilon pakistanicum, along with buddlejoside and lapachol. The structures of new compounds were elucidated by spectroscopic techniques including ¹H‐and ¹³C‐NMR (DEPT), and 2D‐NMR experiments.     

湿法消解-火焰原子吸收光谱法测定青麻不同部位中微量元素

用HNO3和H2O2对样品进行消解,采用火焰原子吸收光谱法直接测定了野生青麻中Fe、Zn、K、Ca、Cu、Mn微量元素。在优化的仪器工作条件下,对青麻中6种微量元素可进行分别测定,互不干扰,结果的相对标准偏差在5%以内,加标回收率在83.3%~105%。方法简单、准确,结果令人满意。