Gopalamicin, an antifungal antibiotic, was isolated from the cells of two actinomycetes, . Gopalamicin is structurally similar to salbomycin and elaiophylin. Gopalamicin completely inhibited the growth of all pathogenic fungi tested in vitro at 12-16 ppm. Similarly, it was somewhat effective in controlling wheat powdery mildew, grape downy mildew, and rice blast pathogens in greenhouse experiments. Gopalamicin was ineffective against all Gram-positive and -negative bacteria tested.
In spite of considerable efforts by many workers, there has been a lack of progress in the area of amine fungicides since fenpropimorph. Random synthesis of a large variety of different amine compounds, as well as intelligent structural modification of the lead structure fenpropimorph (well over 15 000 amines have been screened at BASF alone) have not led to a new market product so far. Further work has been focused on the reported mode of action of fenpropimorph, notably on the inhibition of the sterol Δ14‐reductase. Although some doubt has to be cast on the hypothesis that fenpropimorph behaves as a sterol mimic, the concept of ‘high energy intermediate’ inhibitors has been employed successfully. Rational drug design of azasterol mimics has led to a number of very potent inhibitors of the sterol Δ14‐reductase which also displayed high fungicidal activity in the greenhouse. Although many of these compounds are more powerful reductase inhibitors than fenpropimorph, under field conditions none showed significant advantages over this established fungicide.
Most likely, fenpropimorph already exhibits the maximum fungicidal activity which can be attained by blocking the sterol Δ14‐reductase. This would mean that, with the development of the ‘second generation’ amine fungicide fenpropimorph, this class of compounds has already virtually been optimized.
Aus dem Rinden-Extrakt von Scufiu buxifoliu Reiss. wurden neben den bereits beschriebenen Peptidalkaloiden Scutianin-A (1) 2) und -B (2)3) drei weitere, Scutianin-C, -D und -E, isoliert und ihre Struktur aufgeklart (3,4,5). Sie geharen zur Gruppe der Cyclopeptidalkaloide mit 14gliedrigem Ringsystem. Mit Scutianin-D und -E wurden erstmals diastereomere Cyclopeptidalkaloide aus einer Pflanze isoliert. Allein Scutianin-E enthalt D-Aminosauren, und zwar D-eryrhro-P-Hydroxyleucin und D-rhreo-P-Phenylserin. Alle Verbindungen haben geringe antibiotische Aktivitat.
Alkaloids from Rhamnaceae, XXIIII)
Scutianine-C, -D, and -E, Three Further Cyclopeptide Alkaloids from
Seuria buxiforia Reiss.Besides the already reported peptide alkaloids scutianine-A (1)2) and -B (Z)3) from the bark extract of Scuriu buxifoliu Reiss. three further alkaloids, scutianine-C, -D, and -E, were isolated and their structures were elucidated (3, 4, 5). They belong to the cyclopeptide alkaloids with a fourteen-membered ring system. Scutianine-D and -E represent the first diastereomeric cyclopeptide alkaloids which have been isolated from the same plant. Only scutianine-E contains D-amino acids and these are D-eryrhro-P-hydroxyleucine and D-rhreo-P-phenylserine. All compounds have a small antibiotic activity. Im Rahmen der Arbeiten uber Alkaloide aus Rhamnaceen war in unserem Institut das Hauptalkaloid der Rinde des brasilianischen Baumes Scutiu buxifoliu Reiss., Scutianin-A (l), isoliert und seine Struktur bestimmt wordenz). Mit einer Rinde, die in der Umgebung von Julio Castilhos in der Provinz Rio-Grande do Sul/Brasilien gesammelt worden war, wurde nunmehr die Untersuchung der Nebenalkaloide vorgenommen. Die fein gemahlene Rinde wurde in ublicher Weisez) aufgearbeitet und das Alkaloidgemisch durch mehrstufige Saulen-und Schichtchromatographie an Kieselgel getrennt. Die Nebenalkaloidejedes liegt in einer Menge von etwa 0.0025 %, bezogen auf die lufttrockene Rinde, vorwurden nach der Reihenfolge zunehmender Polaritat bei der Chromatographie an Kieselgel in System I bezeichnet. Von diesen wurde Scutianin-B (2) bereits beschrieben3).
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