Methyl gallate is a natural constituent of maple (Genus Acer) leaves.

Methyl gallate was found in ethanolic extracts of red maple (Acer rubrum L.), silver maple (A. saccharinum L.) and sugar maple (A. saccharum Marsh) leaves, but more was present in methanolic extracts. The increased amount of methyl gallate in methanolic extracts was accompanied by a disappearance of m-digallate. It is concluded that only some of the methyl gallate detected in methanolic extracts is an artefact as a result of methanolysis of m-digallate. Its presence in ethanolic extracts is evidence that it is also a natural constituent of maple leaves.

Acylated anthocyanins in inflorescence of spider flower (Cleome hassleriana).

Five anthocyanins, cyanidin 3-(2''-(6'''-caffeoyl-beta-glucopyranosyl)-6''-(E-p-coumaroyl)-beta-glucopyranoside)-5-beta-glucopyranoside, cyanidin 3-(2''-(6'''-E-sinapoyl-beta-glucopyranosyl)-6''-(E-p-coumaroyl)-beta-glucopyranoside)-5-beta-glucopyranoside, cyanidin 3-(2''-(6'''-feroyl-beta-glucopyranosyl)-6''-(E-p-coumaroyl)-beta-glucopyranoside)-5-beta-glucopyranoside, pelargonidin 3-(2''-(6'''-E-sinapoyl-beta-glucopyranosyl)-6''-(E-p-coumaroyl)-beta-glucopyranoside)-5-beta-glucopyranoside, and pelargonidin 3-(2''-(6'''-E-p-coumaroyl-beta-glucopyranosyl)-6''-(E-p-coumaroyl)-beta-glucopyranoside)-5-beta-glucopyranoside, together with five known anthocyanins have been identified in flowers of Cleome hassleriana Queen line. One monoacylated and four diacylated cyanidin 3-sophoroside-5-glucosides were identified as the main anthocyanins in flowers with mauve colouration, while a homologous glycosidic pattern based on pelargonidin was found in the five main anthocyanins from flowers with pink colouration. The anthocyanins identified in C. hassleriana share the same glycosidic pattern as anthocyanins isolated from the genera Raphanus, Brassica and Iberis in the sister family Brassicaceae.

Photosynthesis research in Canada from 1945 to the early 1970s.

This history traces the development of photosynthesis research in Canada from 1945 to 1975, starting with the work of Gleb(1) Krotkov and his students, Paul Vittorio, Tony(1) Bidwell, Don(1) Nelson, Jim(1) Craigie, Bruce Tregunna, Andreas Hauschild, Geoff Lister and others in the Department of Biology at Queen's University, Kingston, Ontario. They focused on the influence of taxonomy and light quality on the path of carbon into early products, photorespiration and photosynthesis in young trees. During the same period, Ken(1) Clendenning and one of the authors (PRG) at the National Research Council of Canada (NRCC) laboratory in Ottawa began studies of chloroplast photoreduction and leaf carboxylases. They were joined by Don(1) Mortimer, who showed that the path of carbon varies with species of plant and by Morris Kates, who studied phospholipid enzymology in chloroplasts and leaves. Stan(1) Holt researched the chemistry and distribution of chlorophylls in different taxa. In 1952, Ralph Lewin joined NRCC's new Atlantic Regional Laboratory in Halifax, Nova Scotia, followed by Jim Craigie, Jack McLachlan and Tony Bidwell who mainly investigated the products of photosynthesis in marine algae. Tony Bidwell continued these studies in 1959 at the Department of Botany, University of Toronto. Dave(1) Canvin joined the staff at Queen's in 1965 and became involved in solving the mystery of photorespiration. Tony Bidwell returned to Queen's in 1969 and studied photosynthesis of algal chloroplasts using an 'artificial leaf.' In 1965, Don Nelson established a group at Simon Fraser University in Burnaby, British Columbia that included his former student, Geoff Lister who produced the first photosynthetic action spectra for trees, and Bill(1) Vidaver, who showed the useful relation between chlorophyll fluorescence and photosynthetic activity. In 1970, Mário Fragata headed a group at the Université du Québec à Trois Rivières, Québec, that began with studies of Photosystem II in chloroplasts and particles.

Quercetin glycosides in Psidium guajava L: leaves and determination of a spasmolytic principle

The traditional herbal remedy from Psidium guajava leaves had been medically proposed in mexico as effective treatment of acute diarrhea. A methanolic leaf extract was subjected to a bioassay-guided isolation of spasmolytic constituents. Six fractions were separated on a polyvinylpolypyrrolidine (PVPP) columm using a water methanol-gradient. The fraction containing flavonols inhibited peristalsis of guinea pig ileum in vitro. A trace of quercetin aglycone together with five glycosides was isolated from this active fraction and identified as quercentin 3-O-alpha-L-arabinoside (guajaravin); quercetin 3-O-ß-D-glucoside (isoquercetin); quercetin 3-O-ß-D-galactoside (hyperin); quercetin 3-O-ß-L-rhamnoside (quercitrin) and quercetin 3-O-gentobioside. Biological activity of each pure compound was studied in the same bioassay. Obtained results suggets that the spasmolytic activity of the Psidium guajava leaf remedy is mainly due to the aglycone quercetin, present in the leaf and in the extract mainly in the form of live flavonols, and whose effect is produced when these products are hydrolyzed by gastrointestinal fluid

LIPID RESERVES OF SEEDS OF IMPATIENS CAPENSIS AND I. PALLIDA (BALSAMINACEAE): DEVELOPMENTAL ASPECTS.

It has been known since 1948 that seeds of Impatiens species (family Balsaminaceae) contain a polyconjugated 18:4 fatty acid, α-parinaric acid. Content of this acid is high in seeds of the two species of Impatiens native to eastern North America, I. capensis Meerb. and I. pallida Nutt. The cotyledons of these seeds also have an unusual blue pigmentation that disappears when lipids are extracted. Deposition of oil reserves and appearance of cotyledon color was observed during fruit development. Pods of I. capensis and I. pallida were measured daily after anthesis. Length increased linearly to a maximum of about 27 mm (I. capensis) and 30 mm (I. pallida) by day 10 after which increase in girth and fresh weight of pods, and fresh weight of seeds, increased exponentially. At maturity (15 days) seeds of I. pallida were twice the weight of seeds of I. capensis. Lipid reserves, extracted with chloroform-methanol, were detectable by day 6 and increased rapidly to 28% fresh weight (2 mg/seed) in seeds of I. capensis and to 24% (4 mg/seed) in I. pallida. The characteristic ultra-violet (uv) spectrum of α-parinaric acid was already present by day 6, and content of this acid increased to 42% of total lipids in I. capensis and to 30% in I. pallida at maturity. Fatty acids as determined by gas chromatography of oil of mature seeds were 16:0 (13%, I. capensis; 11%, I. pallida); 16:1 (trace); 18:0 (2%); 18:1 (20%, 25%); 18:2 (17%, 14%); 18:3 + 18:4 (48%, 47%). Electron micrographs of mature seeds of I. capensis showed abundant oleosomes and protein bodies. The blue color of the cotyledons was faint at day 11 and then intensified with age. It was somewhat paler in I. pallida than in I. capensis, suggesting that it may be associated with the presence of α-parinaric acid.