No abstract

Various cultivars of Perilla frutescens (L.) (var. crispa and var. frutescens) Britt. were harvested in China and Japan. They were easily differentiated on the basis of their foliage color, that varied from red to green. Water extracts of dried plants were investigated for their antioxidant activity (AA) and their polyphenolic compounds compared. Among them, cinnamic acid derivatives (coumaroyl tartaric acid, caffeic acid and rosmarinic acid), flavonoids (apigenin 7-O-caffeoylglucoside, scutellarein 7-O-diglucuronide, luteolin 7-O-diglucuronide, apigenin 7-O-diglucuronide, luteolin 7-O-glucuronide, and scutellarein 7-O-glucuronide) and anthocyanins (mainly cis-shisonin, shisonin, malonylshisonin and cyanidin 3-O-(E)-caffeoylglucoside-5-O-malonylglucoside) were quantified. AA assays are based on the inhibition of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The DPPH radical scavenging activity was calculated as Trolox® [(±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid] equivalent antioxidant capacity (TEAC). The mean amount of total phenolics of the water extracts (4-29 µmol/100 mL) and the TEAC value calculated (23-167 µmol TE/100 mL) confirmed the high antioxidant activity of these leaf water extracts. These results were highly correlated within some o-dihydroxylated polyphenolic compounds and AA.

Mango (Mangifera indica L.) byproducts, which represent 35-60 % of the processed fruit, are a potential source of dietary fiber. After ethanolic purification, we found that peels and fibrous waste pulp had a high dietary fiber content (74% of the dry matter) with a soluble/insoluble ratio close to 1 and a 15-20 % uronic acid content. The fiber water-soluble fraction showed shear-thinning behavior. In vitro studies indicate that these fibers decreased total starch digestibility and slowed the final rate of amylolysis of mashed potatoes as the starch source. Glucose diffusion was also retarded in the presence of mango fiber. These results suggest that mango byproducts are a good source of dietary fiber which could be of potential benefit in controlling plasma glucose.

a CIRAD, UMR CIRAD-16, Ge ´nie des proce ´de ´s, eau et bioproduits (GPEB), Centre de coope ´ration internationale en recherche agronomique pour le de ´veloppement (CIRAD), TA B64/16, 73, avenue Agropolis,