G. Roger Fenwick

Improved method for the determination of the total glucosinolate content of rapeseed by determination of enzymically released glucose

A method is described for the determination of the total glucosinolate content of rapeseed. The method is an improvement of a previously described procedure and avoids the necessity for a defatting step. The new and old methods are compared with each other and with a high-performance liquid chromatographic method.

Induction of glutathione S-transferase activity in hepG2 cells by extracts from fruits and vegetables

Abstract The human hepatoma cell line, hepG2, retains many of the xenobiotic metabolising enzymes found in normal hepatocytes, including an inducible glutathione S -transferase (GST). The isoform of GST that is induced by xenobiotics in this cell line is GSTA1-1. As a first step to determining the effect of diet on induction of GST in humans, we have examined the ability of extracts from a wide variety of fruits and vegetables to induce GST activity in hepG2 cells. Extracts from cruciferous vegetables (broccoli, Brussels sprouts, cabbage) were the most potent inducers, but this was dependent on the variety. Most of the extracts from fruits, with the exception of grapefruit, were poor inducers. Similarities and differences between the induction of GST and of quinone reductase in mouse hepalclc7 cells are discussed. The results show that extracts from cruciferous vegetables are effective inducers of human GST, in agreement with previous studies on GST in animals and cell lines derived from animals.

A TLC method for the analysis of quinoa (Chenopodium quinoa) saponins

Abstract A method is described which enables both the total saponin content and composition to be assayed in quinoa plant tissue. The saponin composition has been determined according to the three main groups of saponins found in quinoa which contain oleanolic acid, hederagenin and phytolaccagenic acid as the aglycone in each group. The method has been used to measure the saponin content of 15 ecotypes being used in a breeding programme in the UK and to compare the saponins present in sweet and bitter varieties.

Effect of seed size and testa colour on saponin content of Spanish lentil seed

Twenty cultivars of Lens culinaris Medik. were grown over 5 years in 18 provinces of Spain. Saponin content in the harvested seed ranged from 654 to 1269 mg kg−1. Two saponins were detected and identified as soyasaponins I and VI. Changes observed in the saponin content were found to be dependent on both seed size and testa colour. Lentils of the subspecies macrosperma were found to have a significantly higher saponin content (1105 mg kg−1) than seeds of the subspecies microsperma (929 mg kg−1). The total saponin content of seeds with a brown testa was significant lower (800 mg kg−1) than those with a beige or green testa (1106 and 1089 mg kg−1, respectively).