Diversité d’usages et Statut de conservation de Syzygium guineense (Willd.) DC. subsp. macrocarpum (Engl.) F. White (Myrtaceae) au Bénin

2019 ◽  
Vol 76 (5) ◽  
pp. 827-842
Author(s):  
Romaël Badjrêhou Badou ◽  
Hounnankpon Yedomonhan ◽  
Monique Tossou
Keyword(s):  
Syzygium Guineense

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

A Novel Normethylfriedelane-Type Isoprenoid from Syzygium guineense Stem Bark

2018 ◽  
Vol 54 (1) ◽  
pp. 112-116
Author(s):  
I. A. Oladosu ◽  
O. O. Aiyelaagbe ◽  
O. E. Afieroho
Keyword(s):  
Stem Bark ◽  
Syzygium Guineense

Stagonospora atriplicis. [Descriptions of Fungi and Bacteria].

2005 ◽  
Author(s):  
T. V. Andrianova
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Czech Republic ◽  
New Zealand ◽  
Geographical Distribution ◽  
Biological Control Agent ◽  
Control Agent ◽  
Allenrolfea Occidentalis ◽  
Syzygium Guineense

Abstract A description is provided for Stagonospora atriplicis, a potential biological control agent of Atriplex and Chenopodium weeds. Information is included on the disease caused by the organism, its transmission, geographical distribution (Kenya, South Africa, Zimbabwe, Canada, USA, Colombia, Cyprus, Georgia, Kyrgyzstan, Russia, Australia, New Zealand, Austria, Belgium, Bulgaria, Czech Republic, Estonia, France, Germany, UK, Hungary, Italy, Latvia, Romania, Sweden, Ukraine and Hawaii) and hosts (Allenrolfea occidentalis, Atriplex spp., Chenopodium spp. and Syzygium guineense).

scholarly journals Identification of Ellagic Acid Derivatives from Stem Bark of Syzygium Guineense (Myrtaceae)

2007 ◽  
Vol 2 (3) ◽  
pp. 1934578X0700200
Author(s):  
Jules Desire Djoukeng ◽  
Eliane Abou-Mansour ◽  
Leon Azefack Tapondjou ◽  
David Lontsi ◽  
Raffaele Tabacchi
Keyword(s):  
Ellagic Acid ◽  
Radical Scavenging ◽  
2D Nmr ◽  
Stem Bark ◽  
Dpph Assay ◽  
Spectrometric Data ◽  
Esi Ms ◽  
Syzygium Guineense ◽  
Fragmentation Patterns

An LC-DAD-ESI-MSn technique was developed to investigate crude extracts of the stem bark of S. guineense for phenolic compounds. Ellagic acids were detected on the basis of their UV absorption spectra and ESI-MS fragmentation patterns. Six ellagic acid conjugates in the complex extract of S. guineense were identified. With the aim to confirm the structures, further purification of the extract afforded the known 3-O-ellagic acid-4′-O-α-rhampyranonosides (3), two new ellagic acid rhamnopyranosides, 3-O-methylellagic acid-4′-O-α-2″-O-acetylrhamnopyranoside (4) and 3-O-methylellagic acid-4′-O-α-3″-O-acetylrhamnopyranoside (6). The structures were identified on the basis of 1D- and 2D- NMR, IR, and UV spectroscopic and mass spectrometric data. The HMBC and NOESY data of these compounds were most useful for determination of their structures. Radical scavenging activities were evaluated in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 3, 4 and 6, with IC50 values of 6.1 ± 0.5, 5.8 ± 0.4, and 6.2 ± 0.4 μM, respectively were as active as ellagic acid (1) (IC50 = 4.9 ± 0.3 μM) and more active than catechin (IC50=10.8 ± 0.3 μM).

scholarly journals Étude ethnobotanique et variabilité morphologique de Syzygium guineense var. macrocarpum dans les hautes savanes guinéennes de l’Adamaoua (Cameroun)

2020 ◽  
Vol 343 ◽  
pp. 83-84
Author(s):  
Georges Maxime Lamy Lamy
Keyword(s):  
Étude Ethnobotanique ◽  
Syzygium Guineense

La problématique de la variabilité morphologique des feuilles et fruits de nombreuses plantes locales multifonctionnelles préoccupe les chercheurs africains. À cela s’ajoute la menace de disparition de certaines de ces plantes vivant encore naturellement. Dans la zone agroécologique des hautes savanes guinéennes de l’Adamaoua au Cameroun se rencontre Syzygium guineense var. macrocarpum (Engl.) F. White, une myrtacée endémique. Pour sa domestication, un problème de choix des sous-variétés à retenir s’est posé. L’ethnobotanique étant la relation entre l’Homme et les plantes dans un milieu donné à travers le temps, la prise en compte du savoir et des préférences locales était indispensable. Par ailleurs, les objectifs visaient à identifier, décrire et déterminer les descripteurs morphologiques (qualitatifs et quantitatifs) et les sous-variétés de la plante. Les personnes enquêtées étaient constituées de 218 hommes et femmes appartenant à neuf ethnies différentes. Dans des quadrats de 100 m x 100 m, 256 arbres des sous-variétés de la plante ont été sélectionnés. Le dispositif expérimental était un plan factoriel (8 x 4 x 8 x 3) : 8 x 4 pour l’unité expérimentale ; 8 pour le nombre de sites d’étude ; 4 pour le nombre de sous-variétés ; 3 pour le nombre de répétitions (3 feuilles et 3 fruits sur chaque pied), les sites étant le traitement principal et les sous-variétés le traitement secondaire. L’évaluation des descripteurs morphologiques a été respectivement faite sur 768 feuilles et fruits. Les critères de différenciation paysanne étaient liés à l’observation (couleur, forme, etc.) des arbres, feuilles et fruits. Les descripteurs de l’accessibilité à une meilleure luminosité de l’arbre, du rendement et du développement végétatif pourront servir de références lors de la domestication de la plante. Les sous-variétés 1, 2 et 3 étaient hautement significatives, de par leur valeur d’usage ethnobotanique total, supérieure à 3 parmi les 4 recensées. Des études moléculaires utilisant les ADN génomiques (chloroplastique et ribosomal) permettront de tirer une conclusion définitive quant à l’origine environnementale ou moléculaire de la variabilité observée au sein de la plante dans cette zone.

scholarly journals Antidiabetic potentials of Syzygium guineense methanol leaf extract

2016 ◽  
Vol 5 (4) ◽  
pp. 150-156
Author(s):  
Ifeoma Chinwude Ezenyi ◽  
◽  
Oluchi Nneka Mbamalu ◽  
Lucy Balogun ◽  
Liberty Omorogbe ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Leaf Extract ◽  
Density Lipoprotein ◽  
Hepatic Glycogen ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Oral Glucose Tolerance ◽  
Control Serum ◽  
Syzygium Guineense ◽  
Alpha Glucosidase

This study examines the effects of a methanol extract of Syzygium guineense leaves in streptozotocin (STZ) - induced diabetes, evaluates its effect on alpha glucosidase and 2, 2-diphenyl-1-picrylhydrazyl radical. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (60 mg/kg). An oral glucose tolerance test was performed after diabetes induction and repeated after 14 days of treatment with the extract. The extract elicited antihyperglycemic action in diabetic rats evidenced by an improved oral glucose tolerance. A dose of 250 mg/kg of extract significantly (P<0.01, 0.001) enhanced glucose clearance at the end of treatment period and was comparable with metformin, the group also showed increase in hepatic glycogen content by 33.9% relative to the diabetic control. Serum biochemical analysis showed that the extract improved indices of renal and hepatic function by reduction in serum albumin, creatinine, liver enzymes, total and direct bilirubin. Similarly, the extract reduced serum cholesterol, triglycerides and high density lipoprotein (HDL) in a non-dose dependent manner; treatment with 250 mg/kg extract caused significant (P<0.05) reduction of HDL. Groups which received 250 and 500 mg/kg of extract showed reversal of glomerular damage compared with the diabetic untreated group. The extract also exhibited concentration-dependent antioxidant activity (EC50= 0.2 mg/ml) and statistically significant (P<0.01, 0.001) alpha glucosidase inhibitory effect (IC50= 6.15 mg/ml). These findings show the antidiabetic potential of S. guineense leaf extract, likely mediated through its ability to inhibit alpha glucosidase, scavenge free radicals and increase intrahepatic glucose uptake and storage.

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