Niranjan P. Sahu

Synthesis of a novel quinoline derivative, 2-(2-methylquinolin-4-ylamino)-N-phenylacetamide—a potential antileishmanial agent

Some novel quinoline derivatives were prepared and tested for antileishmanial activity. 2-(2-Methylquinolin-4-ylamino)-N-phenylacetamide (2) was found to be significantly more active than the standard antileishmanial drug sodium antimony gluconate (SAG) in reducing the parasite load both in the spleen and liver at a much lower concentration in hamster models. The results suggest that the compound could be exploited as an antileishmanial drug.

Flavonol glycosides from Calotropis gigantea

Besides isolation and characterization of isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucopyranoside and taraxasteryl acetate, a new flavonol trisaccharide was isolated from the aerial parts of Calotropis gigantea, and its structure was established as isorhamnetin-3-O-[2-O-beta-D-galactopyranosyl-6-O-alpha-L-rhamnopy ranosyl]- beta-D-glucopyranoside by a combination of fast atom bombardment mass spectroscopy, 1H and 13C NMR spectra and some chemical degradations.

Steroidal alkaloids from Solanum khasian um: Application of 13C NMR spectroscopy to their structural elucidation

Abstract The solasodine glycosides, solasonine, solamargine and khasianine have been isolated from berries of Solanum khasianum and characterized by 13 C NMR spectroscopy. By application of this method, the structure of khasianine has been elucidated as O -α- l -rhamnosyl (1→4 glu )- O (3)-β- d -glucopyranosyl-solasodine (β 2 -solamargine).

Triterpenoids and their glucosides from Terminalia bellerica

Abstract In addition to the isolation and identification of arjungenin and its glucoside, the structures of a new triterpene, belleric acid and its glucoside, bellericoside have been defined as 2α,3β,23,24-tetrahydroxyolean-12-en-28-oic acid and its β- d -glucopyranosyl ester.

Triterpenoid saponins from Gymnema sylvestre

Besides six known gymnemic acids, four new tritepenoid saponins, gymnemasins A, B, C and D, isolated from the leaves of Gymnema sylvestre, were identified as 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucuronopyranosyl]-22-O- tigloyl- gymnemanol, 3-O-[beta-D-glucopyranosyl (1-->3)-beta-D-glucuronopyranosyl]-gymnemanol, 3-O-beta-D-glucuronopyranosyl-22-O-tigloyl-gymnemanol and 3-O-beta-D-glucuronopyranosyl-gymnemanol, respectively. The aglycone, gymnemanol, which is a new compound, was characterized as 3 beta, 16 beta, 22 alpha, 23, 28-pentahydroxyolean-12-ene.

Spectroscopic determination of structures of triterpenoid trisaccharides from Centella asiatica

Abstract The structures of two new triterpenoid trisaccharides asiaticoside-A and asiaticoside-B from Centella asiatica have been elucidated as the [O-α- l -rhamnopyranosyl-(1→4)-O-β- d -glucopyranosyl(1→6)]-O-β- d -glucopyranose ester of 2α,3β,6β,23α-tetrahydroxy-urs-12-ene-28-oic acid and the [O-α-[spl-rhamnopyranosyl-(1→4)-O-β- d -glucopyranosyl (1→6)]-O-β- d -glucopyranose ester of 2α,3β,6β,23α-tetrahydroxyolean-12-ene-28-oic acid by spectroscopic analysis.

Potential antitumor agents from Lantana camara : Structures of flavonoid -, and phenylpropanoid glycosides

Abstract Besides the known glycosides, verbascoside and a flavone glycoside, a novel flanonol glycoside named camaraside and a new phenylpropanoid glycoside, lantanaside have been isolated from the leaves of Lantana camara and defined as 3,5-dihydroxy-4′,6-dimethoxyflavonol-7-O-glucopyranoside and 3,4-dihydroxy-,β-phenylethyl-O-α-L-rhamnopyranosyl (1→3)-4-O- cis- caffeoyl- β -D-glucopyranoside respectively by spectroscopic methods and chemical transformations.

Polyoxypregnane glycosides from the flowers of Dregea volubilis.

Three novel polyoxypregnane glycosides, volubiloside A, B and C (1-3), were isolated from the flowers of Dregea volubilis Linn., and their structures were elucidated as drevogenin D-3-O-beta-D-glucopyranosyl (1-->4)-6-deoxy-3-O-methyl-beta-D-allopyranosyl (1-->4)-beta-D-cymaropyranosyl (1-->4)-beta-D-cymaropyranoside, drevogenin D-3-O-beta-D-glucopyranosyl (1-->4)-6-deoxy-3-O-methyl-beta-D-allopyranosyl (1-->4)-beta-D-cymaropyranosyl (1-->4)-beta-D-digitoxopyranoside and drevogenin P-3-O-beta-D-glucopyranosyl (1-->4)-6-deoxy-3-O-methyl-beta-D-allopyranosyl (1-->4)-beta-D-cymaropyranosyl (1-->4)-beta-D-cymaropyranoside, respectively, on the basis of extensive NMR experiments, MALDI-TOF MS, and some chemical strategies.

Anti-inflammatory triterpene saponins of Pithecellobium dulce: Characterization of an echinocystic acid bisdesmoside

A new bisdesmodic triterpenoid saponin, dulcin was isolated from the seeds of Pithecellobium dulce and was identified as 3-O-[beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranosyl]- 28-O-[beta-D-xylopyranosyl (1-->6)-beta-D-glucopyranosyl]-echinocystic acid. The known oleanolic acid saponin PE, oleanolic acid 3-O-beta-D-glucopyranosyl (1-->2)-alpha-L-arabinopyranoside was also obtained. The structural features were elucidated by a combination of spectroscopic methods and some chemical transformations.

Structure elucidation of four new triterpenoid oligoglycosides from anagallis arvensis

Abstract Besides characterisation of desglucoanagalloside, anagallisins A,B,D and E, four new triterpenoid oligoglycosidesisolated from the aerial part of Anagallis arvensis were respectively defined to be anagalligenin B 3-0-{β-D-xylopyranosyl (1 → 2) -β-D-glucopyranosyl (1 → 4)-[β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl (1 → 2)]-α-L-arabinopyranoside} (1), anagalligenone 3- 0 -{β-D-xylopyranosyl (1 ar 2)-β-D-glucopyranosyl (1 ar 2)-β-D-glucopyranosyl(1 ar 4)-[β-D-glucopyranosyl (1 → 2)]-α-L-arabinopyranoside} (2), anagalligenone 3- 0 -{β-D-xylopyranosyl (1 ar 2)-α-D-glucopyranosyl (a ar 4)-[β-D-glucopyranosyl-(1 ar 2)]-α-L-arabinopyranoside) (4) and anagalligenin B-3- 0 -{β-D-glucopyranosyl (1 → 2)-[β-D-glucopyranosyl (1 ar 4)]-α-L-arabinopyranoside} ( 5 ). The structural features were elucidated by a combination of fast - atom - bombardment mass spectrometry, strategic chemical degradation, and 1 H and 13 C NMR spectroscopy.