Four new cyclodepsipeptides, trichodestruxins
A–D (1–4), together with destruxin
E2 chlorohydrin
(5) and destruxin A2 (6), were isolated
from the plant endophytic fungus Trichoderma harzianum by a bioassay-guided fractionation method. Their planar structures
were elucidated on the basis of 1D and 2D NMR and MS/MS spectroscopic
analyses. The stereochemical configuration was established by application
of the advanced Marfey’s method, J-based configuration
analysis, Mosher’s method, and chemical derivatizations. Trichodestruxin
B contains hydroxy acid fragments of the THPA unit, while trichodestruxins
A and C contain the β-methylproline moiety. All cyclodepsipeptides
displayed cytotoxicity against HT-29, A549, and/or P388 cell lines
with IC50 values of 0.7–19.1 μM.
Euphorbia maculata is a medicinal plant of the Euphorbiaceae family, which can produce anti-inflammatory and cancer chemopreventive agents of triterpenoids. The present study reports on the bioactive triterpenoids of this plant. Two new lanostane-type triterpenoids, named (3S,4S,7S,9R)-4-methyl-3,7-dihydroxy-7(8→9) abeo-lanost-24(28)-en-8-one (1) and 24-hydroperoxylanost-7,25-dien-3β-ol (2), together with 15 known triterpene derivatives, were isolated from Euphorbia maculata. The structures of the new compounds were determined on the basis of extensive spectroscopic data (UV, MS, 1H and 13C-NMR, and 2D NMR) analysis. All tetracyclic triterpenoids (1–11) were evaluated for their anti-inflammatory effects in the test of TPA-induced inflammation (1 μg/ear) in mice. The triterpenes exhibited significant anti-inflammatory activities.
Dturing the early period of the twentieth century, it was generally thought that alkaloids were byp)roducts of a number of irreversible and physiologically useless reactions associated with nitrogen metabolism (1-3). This idea was gradually discarded as an increasing number of experiments showed that alkaloids are metabolically active.Indirect evidence for the decomposition of ricinine (II, fig 1) (7) has been made on the degradation of ricinine in a cell-free system of young castor plants. Tso and Jeffrey (8) were the first to use isotopic tracers to demonstrate that alkaloids are metabolically active. They fed nitrogen-15 labeled nicotine (III, fig 1), nornicotine and anabasine (IV, fig 1)
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