Special metabolites isolated from Urochloa humidicola (Poaceae)

ABSTRACT This study aims to identify special metabolites in polar extracts from Urochloa humidicola (synonym Brachiaria humidicola) that have allelopathic effects and induce secondary photosensitization in ruminants. The compounds were isolated and identified via chromatographic and spectroscopic techniques. The compounds 4-hydroxy-3-methoxy-benzoic acid, trans-4-hydroxycinnamic acid, and p-hydroxy-benzoic acid; the flavonols isorhamnetin-3-O-β-d-glucopyranoside and methyl quercetin-3-O-β-d-glucuronate; and kaempferitrin, quercetin-3-O-α-l-rhamnopyranoside, and tricin were identified in the extract from the leaves of Urochloa humidicola. Two furostanic saponins, namely, dioscin and 3-O-α-l-rhamnopyranosyl-(1-4)-[α-l-rhamnopyranosyl-(1-2)]-β-d-glucopyranosyl-penogenin, as well as catechin-7-O-β-d-glucopyranoside were identified in the methanolic extract obtained from the roots of this plant. This species features a range of metabolites that may be toxic for animals if used in food and may interfere with the growth medium, thereby inhibiting the development of other species.

Evidence of the Presence of Thyroid Hormones in Achatina fulica Snails

ABSTRACT The objective of this study was to identify thyroid hormones and to examine their putative site of synthesis in Achatina fulica snails. For this purpose, radioimmunoassays were performed for T3 and T4 before and after long starvation with or without hemolymph deproteinization. Sodium/iodide symporter activity in vivo was analyzed through 125I administration with and without KClO4 pretreatment. Only T4 was detected, and its concentration decreased due to starvation or deproteinization. However, high-performance liquid chromatography analysis also showed the presence of T2 and T3 apart from T4, but rT3 was not detected in the A. fulica hemolymph. The sodium/iodide symporter activity was greater in cerebral ganglia than digestive gland, but KClO4 treatment did not inhibit iodide uptake in any of the tissues analyzed. Altogether, our data confirm for the first time the presence of thyroid hormones in A. fulica snails and suggest their participation in the metabolism control in this species, although the putative site of hormone biosynthesis remains to be elucidated.

Distribution of metabolites in galled and non-galled leaves of Clusia lanceolata and its antioxidant activity

Essential oils of galled and non-galled leaves of Clusia lanceolata Cambess., Clusiaceae, were obtained by hydrodistillation and analyzed by GC and GC/MS. The chemical composition of both oils was similar, with a predominance of sesquiterpene caryophyllenes. The extracts from the leaves were evaluated regarding total phenols, flavonoids and proanthocyanidins. Galled leaves showed higher levels of phenolics and proanthocyanidins, since the content of flavonoids was higher in non-galled leaves. The chromatographic profiles of extracts were obtained by using HPLC/DAD and LC-ESI-MS. Electrospray ionisation (ESI) in positive and negative ion mode was used to identify four flavones C-glycosides in both extracts. The study constitutes a first report on the chemical research of C. lanceolata. The extract from galled leaves had a higher antioxidant activity.