New lamellarin alkaloids from the Indian ascidian Didemnum obscurum and their antioxidant properties.
Three new lamellarin alkaloids, lamellarins gamma (1), alpha (2), and epsilon (3), along with eight known lamellarin alkaloids, lamellarins M (4), K (5), K-diacetate (6), K-triacetate (7), U (8), I (9), C-diacetate (10), and X-triacetate (11), have been isolated from the Indian ascidian Didemnum obscurum. The structures of 1-11 were established using standard spectroscopic techniques. The structure of lamellarin K-triacetate (7) was further confirmed by X-ray crystallographic analysis. The antioxidant properties of lamellarin gamma, lamellarin gamma-monoacetate, lamellarins K, U, and I, and lamellarin C-diacetate were evaluated.
Natural Products Laboratory, Organic Chemistry Division-I, X-ray Crystallographic Division, and Pharmacology Division, Indian Institute of Chemical Technology, Hyderabad-500 007, India.
P
P
Krishnaiah
V L N
VL
Reddy
G
G
Venkataramana
K
K
Ravinder
M
M
Srinivasulu
T V
TV
Raju
K
K
Ravikumar
D
D
Chandrasekar
S
S
Ramakrishna
Y
Y
Venkateswarlu
D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D003374:Coumarins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D018360:Crystallography, X-Ray; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007194:India; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D014561:Urochordata / Q000737:chemistry*
D000470:Alkaloids; D000975:Antioxidants; D003374:Coumarins; D006576:Heterocyclic Compounds, 4 or More Rings; C489096:lamellarin alpha; C489095:lamellarin epsilon; C489094:lamellarin gamma