ABSTRACT
Gakolanone (3',5'-digeranyl-2',4',6',3-tetrahydroxybenzophenone; 1), a novel benzophenone derivative was isolated from the hexane extract of Garcinia kola Heckel stem-bark along with three known 3-8'' linked biflavonoids: 3'',4',4''',5,5'',7,7''-heptahydroxy-3,8''-biflavanone (2); 3'',4',5,5'',5''',7,7''-heptahydroxy-4-methoxy-3,8''-biflavanone (3) and 4',4''',5,5'',7,7''-hexahydroxy-3,8''-biflavanone (4) from the ethanol extract. The compounds were characterized primarily using 1 D and 2 D nuclear magnetic resonance spectroscopy and mass spectrometry and by comparing with literature. The compounds were subjected to in-vitro alpha-amylase enzyme inhibitory assay using DNSA (3,5-dinitrosalicylic acid) reagent with acarbose used as the standard drug. All the compounds were found to show alpha-amylase inhibitory activities with IC50 of 21.4 ± 1.5, 9.9 ± 0.2, 15.3 ± 2.3, 12.9 ± 2.3 µg/mL respectively. All the compounds exhibited better alpha-amylase inhibitory activities than the standard drug, acarbose (IC50= 38.1 ± 8.3 µg/mL).
Subject(s)
Benzophenones/isolation & purification , Garcinia kola/chemistry , Benzophenones/pharmacology , Biflavonoids/chemistry , Biflavonoids/isolation & purification , Enzyme Inhibitors/pharmacology , Inhibitory Concentration 50 , Plant Bark/chemistry , Plant Extracts/chemistry , alpha-Amylases/antagonists & inhibitorsABSTRACT
Two new prenylflavanones named sigmone and sigmotriol have been isolated from the stem bark of Erythrina sigmoidea along with two known constituents 8-(3"-methylbut-2"-enyl)-7,3',4'-trihydroxyflavanone and 7,3',4'-trihydroxyflavanone. Their structures were elucidated by spectroscopic methods.
Subject(s)
Erythrina/chemistry , Flavanones/chemistry , Molecular StructureABSTRACT
A new prenylflavanone dimer named bis-sigmodiol was isolated from Erythrina sigmoidea, along with six known constituents isobavachin, lupiwighteone, orientanol A, ergosta-4, 6, 8 (14), 22-tetraen-3-one, lupenyl acetate, and p-hydroxybenzoic acid. These known constituents have not been reported so far from E. sigmoidea. Their structures were elucidated by spectroscopic methods.
Subject(s)
Erythrina/chemistry , Flavonoids/isolation & purification , Flavonoids/chemistry , Molecular Structure , Nigeria , Nuclear Magnetic Resonance, Biomolecular , Plant Bark/chemistry , Plant Stems/chemistryABSTRACT
Free radicals are involved in the process of lipid peroxidation and play a cardinal role in numerous chronic diseases like cancer, coronary heart disease and ageing. Thus the ability to scavenge free radicals in order to minimize oxidative damage to living cells is very important. The hexane extract of Acalypha hispida (Burn F.) was screened for phytochemical constituents and was found to contain flavonoids, carbohydrates, phenols and alkaloids. Fractions obtained from chromatographic separation were screened for free radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and hydrogen peroxide. Out of the sixteen pooled fractions (S1-S16) screened, compounds S10 (91.8 %), S11 (93.8 %), S14 (92.5 %) and S15 (91.4 %) at a concentration of 0.1 mg/ml had significant antioxidant activities when compared to the known antioxidant ascorbic acid (90.9 %). However, in the analysis using hydrogen peroxide, S1 (99.5 %), S9 (99.2 %), S10 (95.4 %),S11 (95.8 %) and S15 (95.6 %) gave better activity than ascorbic acid (94.8 %), while only S1 and S9 were more effective than butylated hydroxylanisole (98.9 %) and α-Tocopherol (99.1 %) at the same concentration. The cytotoxicity analysis using the Brine Shrimp lethality test gave LC50 values greater than 1000 µg/ml for some of the fractions indicating very low level of toxicity. The better scavenging activity of A. hispida could be linked to the presence of secondary plant products like flavonoids and phenols, which have the ability to scavenge hydroxyl radicals, superoxide anions and lipid peroxy radicals.
ABSTRACT
Species of the genus Phyllanthus are known for their medicinal values and many are explored phytochemically. Some of them produce phthalates which usually have antimicrobial properties. This paper deals with the phytochemical investigation on Phyllanthus muellerianus. As a result, five compounds, bis(2-ethyloctyl)phthalate (1), bis(2-ethylicosyl)phthalate (2), 3-friedelanone (3), beta-sitosterol (4), and methyl gallate (5), have been isolated and characterized. Metabolites 1 and 2 are new compounds, while 3-5 have been isolated for the first time from this source. Structures of all the isolates were established on the basis of MS, 1D and 2D NMR spectral data and in comparison with the reported data.
