ABSTRACT
A new germacrane derivative, care none (1) was isolated from the stems of a well-known medicinal plant, Carissa spinarum L. together with a new ester, 3'-(4''-methoxyphenyl)-3-oxo-ropionyl hexadecanoate (2). Their structures were established using 1D, 2D NMR spectroscopic and synthetic methods. The chloroform extract of the plant displayed strong antioxidant (DPPH) activity. Several other known compounds were also isolated for the first time from this active extract. The antioxidant activity of major lignans was studied.
Subject(s)
Antioxidants/isolation & purification , Apocynaceae/chemistry , Palmitates/isolation & purification , Sesquiterpenes, Germacrane/isolation & purification , Sesquiterpenes/isolation & purification , Antioxidants/chemistry , Palmitates/chemistry , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Sesquiterpenes/chemistry , Sesquiterpenes, Germacrane/chemistryABSTRACT
Bioassay-guided fractionation of different extracts of both stem and stem bark of Stereospermum personatum led to the isolation of free-radical-scavenging and xanthine oxidase inhibitory molecules along with three new anthraquinones, sterequinones F-H (1-3), a new naphthoquinone, sterequinone I (4), two new phenethyl esters, 2(4'-hydroxyphenyl)ethyl undecanoate (14) and 2(4'-hydroxyphenyl)ethyl nonacosanoate (15), and a new 3,4,5-trimethoxycinnamyl ether, 2-methoxy-4-[3'-(3'',4'',5''trimethoxyphenyl)allyloxymethyl]phenol (16), together with known compounds. The antioxidant and xanthine oxidase inhibitory potentials of the isolated compounds are reported.
Subject(s)
Anthraquinones/pharmacology , Antioxidants/pharmacology , Bignoniaceae/chemistry , Enzyme Inhibitors/pharmacology , Free Radical Scavengers/pharmacology , Naphthoquinones/pharmacology , Plants, Medicinal/chemistry , Xanthine Oxidase/antagonists & inhibitors , Anthraquinones/chemistry , Anthraquinones/isolation & purification , Antioxidants/chemistry , Antioxidants/isolation & purification , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Free Radical Scavengers/chemistry , Free Radical Scavengers/isolation & purification , India , Medicine, Ayurvedic , Molecular Structure , Naphthoquinones/chemistry , Naphthoquinones/isolation & purification , Plant Bark/chemistryABSTRACT
Hydnocarpus wightiana is advocated in traditional Indian medicine to possess strong antidiabetic activity. In the course of identifying bioactive fractions from Indian medicinal plants we observed that acetone extract of the seed hulls of H. wightiana possess strong free radicals (DPPH and ABTS) scavenging, alpha-glucosidase and moderate N-acetyl-beta-D-glucosaminidase inhibitory activities. Further fractionation of the extract led to the isolation of hydnocarpin, luteolin and isohydnocarpin in substantial yields. All the compounds showed strong ABTS scavenging property. However, only luteolin could display strong DPPH scavenging activity. Furthermore, all the three compounds also showed varying degrees of alpha-glucosidase and N-acetyl-beta-D-glucosaminidase inhibitory activity, luteolin being the superior. The kinetics of alpha-glucosidase inhibition by these compounds showed that acetone extract inhibits the enzyme in competitive manner however, luteolin and isohydnocarpin showed mixed-type inhibition. This is the first report assigning hydnocarpin and isohydnocarpin free radical scavenging, alpha-glucosidase and N-acetyl-beta-D-glucosaminidase inhibitory properties and luteolin as N-acetyl-beta-D-glucosaminidase inhibitor. This study suggests that presence of amphiphilic antioxidant molecules along with enzyme inhibitory activities in the acetone extract of H. wightiana seed hulls may be responsible for the antidiabetic properties as advocated in traditional medicine.
Subject(s)
Hypoglycemic Agents/pharmacology , Malpighiaceae , Phytotherapy , Plant Extracts/pharmacology , Biphenyl Compounds , Diabetes Mellitus/drug therapy , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Free Radical Scavengers/administration & dosage , Free Radical Scavengers/pharmacology , Free Radical Scavengers/therapeutic use , Glycoside Hydrolase Inhibitors , Humans , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/therapeutic use , Medicine, Ayurvedic , Picrates/chemistry , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Seeds , Sulfonic Acids/chemistryABSTRACT
Two novel 1(17)-methyl anthraquinones, sterequinone-A and -D, their biogenetic precursors sterequinone-B, -C, and a new naphthoquinone sterequinone-E along with a known naphthoquinone, sterekunthal-B, have been isolated from the petroleum ether extract of stem bark of Stereospermum personatum. Their structures were established using spectroscopic methods.
Subject(s)
Anthraquinones/chemistry , Bignoniaceae/chemistry , Anthraquinones/isolation & purification , Magnetic Resonance Spectroscopy , Plant Bark/chemistry , Plant Stems/chemistry , Plants, Medicinal/chemistryABSTRACT
A new isomer of mesquitol (2,3-trans-3',4',7,8-tetrahydroxyflavan-3-ol) was isolated from Dichrostachys cinerea in excellent yields. It has shown free-radical scavenging property and alpha-glucosidase inhibitory activities but, it could not display xanthine oxidase inhibitory property. However, it was observed that acylation of 3-OH group significantly enhanced the alpha-glucosidase inhibition and displayed xanthine oxidase inhibitory potential. The structure activity relationship revealed that the degree of lipophilicity played a major role in improving enzyme inhibitory activities. A positive correlation was observed between enzyme inhibitory potential and acyl chain length (upto C-16) of aliphatic esters.
