Dolichandroside A, a new alpha-glucosidase inhibitor and DPPH free-radical scavenger from Dolichandrone falcata seem.

A new phenylpropanoid glycoside, dolichandroside-A, together with seven known compounds alpha-lapachone, lapachol, aloesaponarin II, 8-hydroxydehydroiso-alpha-lapachone, beta-sitosterol, 3,8-dihydroxydehydroiso-alpha-lapachone and verbascoside were isolated from the active ethyl acetate soluble extract of heartwood of Dolichandrone falcata. All except for dolichandroside-A are known compounds, but have been isolated for the first time from this plant. The structure of all these compounds was determined on the basis of 1D- and 2D-NMR spectral data.

Isolation, characterization and chemobiological quantification of alpha-glucosidase enzyme inhibitory and free radical scavenging constituents from Derris scandens Benth.

The hexane and chloroform extracts of Derris scandens have displayed potent alpha-glucosidase inhibitory and moderate free radical scavenging activities. Phytochemical investigation of the active extracts led to the isolation of three new prenylated isoflavones, isoscandinone, scandenin A and scandenin B in addition to scandenone, scandinone and 4', 5', 7-trihydroxybiprenylisoflavone as the main constituents, having alpha-glucosidase enzyme inhibitory and free radical scavenging properties. A reversed-phase HPLC method is developed to quantify these active principles in the plant material, which can serve as an effective quality control method for standardization of D.

Two new tetracyclic triterpenes from the heartwood of Ailanthus excelsa Roxb.

Two new dammarane-type triterpenes, ailexcelone and ailexcelol, together with ocotillone, malabaricol, epoxymalabaricol, lupeol, and sitosterol-3-O-beta-D-glucoside were isolated from the heartwood of Ailanthus excelsa. The structures of the new compounds were established on the basis of 1D- and 2D-NMR data. Ocotillone, malabaricol and epoxymalabaricol were isolated for the first time from A.

Isolation and synthesis of analgesic and anti-inflammatory compounds from Ochna squarrosa L.

Two new furanoflavonoids (1, 2), one new chalcone dimer (3) along with six known compounds, chrysophanol, 5-O-methyl squarrosin, 5-methoxy furano[4'',5'',6,7]flavone, calodenone, lophirone A and lophirone H were isolated from the ethyl acetate-soluble fraction of methanol extract of root bark of Ochna squarrosa. Chrysophanol, calodenone, lophirone A and lophirone H were isolated from this plant for the first time. The structures of all the isolated compounds were confirmed by 1D and 2D spectroscopic data.

Schisandrene, a dibenzocyclooctadiene lignan from Schisandra chinensis: structure-antioxidant activity relationships of dibenzocyclooctadiene lignans.

Phytochemical investigation of the fruits of Schisandra chinensis led to the isolation of 13 lignans including schisandrene (13), a new lignan based on a dibenzocyclooctadiene backbone with an exocyclic double bond. Its structure and absolute configuration were established using NMR, MS, and CD data. Antioxidant activity of the lignans was evaluated using a DCFH-DA cellular-based assay.

Novel antimicrobial diterpenoids from Turraeanthus africanus.

The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10).

Rapid and easy identification of Illicium verum Hook. f. and its adulterant Illicium anisatum Linn. by fluorescent microscopy and gas chromatography.

Illicium verum Hook. f. is used as an herbal tea to treat colic pain in infants.

Antibacterial constituents from the berries of Piper nigrum.

Piper nigrum finds an extensive application in antibacterial preparations belonging to Ayurvedic system of medicine. A bioguided extraction and fractionation of the petroleum ether extract of the berries of P. nigrum afforded 2E, 4E, 8Z-N-isobutyleicosatrienamide (1), pellitorine (2), trachyone (3), pergumidiene (4) and isopiperolein B (5).

Yeast and mammalian alpha-glucosidase inhibitory constituents from Himalayan rhubarb Rheum emodi Wall.ex Meisson.

The methanolic extract of rhizome of Himalayan rhubarb Rheum emodi displayed mild yeast as well as mammalian intestinal alpha-glucosidase inhibitory activity. However, further fractionation of active extract led to the isolation of several potent molecules in excellent yields, displaying varying degrees of inhibition on two test models of alpha-glucosidase. Rhapontigenin, desoxyrhapontigenin, chrysophanol-8-O-beta-d-glucopyranoside, torachrysone-8-O-beta-d-glucopyranoside displayed potent yeast alpha-glucosidase inhibition.