Cytotoxic prenylated phenols of false indigo-bush (Amorpha fruticosa L.)

This study employed the MTT assay to assess the cytotoxicity of one flavan and two stilbene derivatives isolated from the false indigo-bush (Amorpha fruticosa L.) fruits: 5,7-dihydroxy-8-geranylflavanone (1), 2-carboxy-3,5-dihydroxy-4-geranylbibenzyl (2), and 2-carboxy-3-hydroxy-4-prenyl-5-methoxybibenzyl (3). The examined compounds reduced the survival of human cervical and colon tumour cells (HeLa, HT-29, HCT-116, and LS174) with IC50 values ranging from 10.55 to 147.09 μg/mL, except for 1, which did not affect LS174 cells within the tested concentrations. The highest activity was observed for 1 against HeLa cells, and 1 also exhibited the weakest effect against normal foetal lung fibroblasts (IC50 = 166.11 μg/mL), demonstrating good potency and selectivity. Stilbenes 2 and 3 proved efficacious, but lacked selectivity compared to 1. Our findings revealed the cytotoxicity of false indigo-bush constituents, justifying further mechanistic and in vivo investigations, particularly on 5,7-dihydroxy-8-geranylflavanone, which displayed considerable in vitro anticancer capacity and a potentially favourable safety profile.

Isolation and purification of two antioxidant isomers of resveratrol dimer from the wine grape by counter-current chromatography

Resveratrol dimers belong to a group of compounds called stilbenes, which along with proanthocyanidins, anthocyanins, catechins, and flavonols are natural phenolic compounds found in grapes and red wine. Stilbenes have a variety of structural isomers, all of which exhibit various biological properties. Counter-current chromatography with a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water (2:5:4:5, v/v/v/v) was applied to isolate and purify stilbene from the stems of wine grape. Two isomers of resveratrol dimers trans-ε-viniferin and trans-δ-viniferin were obtained from the crude sample in a one-step separation, with purities of 93.2 and 97.5%, respectively, as determined by high-performance liquid chromatography. The structures of these two compounds were identified by (1) H and (13) C NMR spectroscopy. In addition, their antioxidant activities were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant activities of trans-δ-viniferin were higher than that of trans-ε-viniferin in this model. This work demonstrated that counter-current chromatography is a powerful and effective method for the isolation and purification of polyphenols from wine grape. Additionally, the DPPH radical assay showed that the isolated component trans-δ-viniferin exhibited stronger antioxidant activities than trans-ε-viniferin and a little bit weaker than vitamin E at the same concentration.

Amorpha fruticosa - A Noxious Invasive Alien Plant in Europe or a Medicinal Plant against Metabolic Disease?

Amorpha fruticosa L. (Fabaceae) is a shrub native to North America which has been cultivated mainly for its ornamental features, honey plant value and protective properties against soil erosion. It is registered amongst the most noxious invasive species in Europe. However, a growing body of scientific literature also points to the therapeutic potential of its chemical constituents. Due to the fact that A. fruticosa is an aggressive invasive species, it can provide an abundant and cheap resource of plant chemical constituents which can be utilized for therapeutic purposes. Additionally, exploitation of the biomass for medicinal use might contribute to relieving the destructive impact of this species on natural habitats. The aim of this review is to provide a comprehensive summary and systematize the state-of-the-art in the knowledge of the phytochemical composition and the potential of A. fruticosa in disease treatment and prevention, with especial emphasis on diabetes and metabolic syndrome. Also reviewed are aspects related to potential toxicity of A. fruticosa which has not yet been systematically evaluated in human subjects.

A new tropane alkaloid from the leaves of Erythroxylum subsessile isolated by pH-zone-refining counter-current chromatography

Tropane alkaloids are bioactive metabolites with great importance in the pharmaceutical industry and the most important class of natural products found in the Erythroxylum genus. However, these compounds are usually separated by traditional chromatographic techniques, in which the sample is progressively purified in multiple chromatographic steps, resulting in a time- and solvent-consuming procedure. In this work we present the isolation of a novel alkaloid, 6β,7β-dibenzoyloxytropan-3α-ol, together with the two known 3α-benzoyloxynortropan-6β-ol and 3α,6β-dibenzoyloxytropane alkaloids, directly from the crude alkaloid fraction from the leaves of Erythroxylum subsessile, by using a single run pH-zone-refining counter-current chromatography method. The ethyl acetate/water (1:1, v/v) biphasic solvent system with triethylamine and HCl as retention and eluter agents, respectively, was used to isolate tropane alkaloids for the first time. The structures of the isolated alkaloids were elucidated by spectroscopic methods.

Analysis of bioactive constituents from the leaves of Amorpha fruticosa L

Amorpha fruticosa L. is a Chinese folk medicine and rich in polyphenols. Fifteen known compounds were isolated and identified from the leaves of A. fruticosa L. They are tephrosin (1), 6a,12a-dehydrodeguelin (2), vitexin (3), afrormosin-7-O-β-d-glucopyranoside (4), 2″-O-α-l-rhamnopyranosyl isovitexin (5), rutin (6), chrysoeriol (7), 7-O-methylluteolin (8), trans-p-coumaric acid (9), 2-benzyl-4,6-dihydroxybenzoic acid-4-O-β-d-glucopyranoside (10), formononetin (11), quercetin (12), apigenin (13), β-sitosterol (14), and β-daucosterol (15). Compounds 3, 4, 5, and 7-9 were isolated from A. fruticosa L. for the first time. Cytotoxicity of individual compounds 3-10 and 90% ethanol extract against human cancer cell lines HCT116 and HepG2 were reported. The results suggested that compounds 7 and 8, and the crude extract exhibited inhibitory effects on human cancer cell line HCT116, at concentrations of 100 μg/mL, 5 μg/mL, and 25 μg/mL at <60% of cell viability rate, respectively. In addition, a valid high-performance liquid chromatography diode array detector method was established to quantitatively analyze compounds 1-12 in the leaves of A. fruticosa L., which was harvested at three different stages of maturity from May 20 to August 10, 2014. The results demonstrated that contents were greatly influenced by the maturity. Total amounts of the analytical constituents gradually increased from May 20 to August 10, with the values ranging from 10.86 mg/g to 18.84 mg/g, whereas bioactive compounds 7 and 8 presented the opposite variation trend. The results of this study may provide data for further study and comprehensive utilization of A. fruticosa L.

RESOURCE