Bryophyllum pinnatum (Lam) Pers. (Crassulaceae) is widely used in folk medicine as leaf juice, aqueous, or hydro-ethanolic extracts. It is also listed as a medicinal plant in several countries such ...as France and Brazil. The main reported constituents are flavone glycosides, especially those with the rare 3-O-α-l-arabinopyranosyl-(1 → 2)-α-l-rhamnopyranoside moiety. Despite several phytochemical screenings indicating the presence of cyanide derivatives or alkaloids, there are no reports of nitrogenous metabolite characterization from this plant species. Nevertheless, the occurrence and the type of such compounds are of particular interest, as they may account for some of the numerous biological activities and ethnomedicinal uses described for B. pinnatum and could be regarded as chemical/taxonomic markers. Consequently, a hydro-ethanolic extract of B. pinnatum was investigated by using UHPLC–HRMS/MS and the nitrile glucoside sarmentosin was detected for the first time within the genus Bryophyllum/Kalanchoe. Considering the wide use of B. pinnatum and its closely related species for health purposes, the target metabolite was isolated by a combination of centrifugal partition chromatography in elution/extrusion mode and MPLC in order to confirm its structure. A linear, selective, precise, fast, and reliable 1H NMR quantitation method was then developed and validated and may become a tool for easy quality assessment of the plant species. The amount of sarmentosin was determined as 2.07% of the examined sample. Sarmentosin was also detected in Kalanchoe laciniata, confirming the occurrence of this compound within the genus.
A molecular probe, 3-amino-2,2,5,5,-tetramethy-1-pyrrolydinyloxy (3ap), was employed to determine the formation rates of one-electron reducing intermediates generated photochemically from both ...untreated and borohydride-reduced Suwanee River fulvic and humic acids (SRFA and SRHA, respectively). This stable nitroxyl radical reacts rapidly with reducing radicals and other one-electron reductants to produce a relatively stable product, the hydroxylamine, which can be derivatized with fluorescamine, separated by HPLC and quantified fluorimetrically. We provide evidence that O2 and 3ap compete for the same pool(s) of photoproduced reducing intermediates, and that under appropriate experimental conditions, the initial rate of hydroxylamine formation (R H) can provide an estimate of the initial rate of superoxide (O2 –) formation. However, comparison of the initial rates of H2O2 formation (R H2O2) to that of R H show far larger ratios of R H/R H2O2 (∼6–13) than be accounted for by simple O2 – dismutation (R H/R H2O2 = 2), implying a significant oxidative sink of O2 – (∼67–85%). Because of their high reactivity with O2 – and their likely importance in the photochemistry of CDOM, we suggest that coproduced phenoxy radicals could represent a viable oxidative sink. Because O2 –/phenoxy radical reactions can lead to more highly oxidized products, O2 – could be playing a far more significant role in the photooxidation of CDOM than has been previously recognized.
The Earth’s environment is mainly composed of the aerosphere, hydrosphere, pedosphere, lithosphere, and biosphere, which constitute a large interactive system. Once entering the environment, chemical ...pollutants will migrate and transform through the atmosphere, water, soil, rock, and organisms, and thus retain in all layers. For example, heavy metal pollutants can be found not only in the hydrosphere, pedosphere, lithosphere, but also in organisms via food chain and air in the form of solid dust. Therefore, it is not reasonable to study a certain pollutant restricted to a single layer.
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