Dinesh K. Kulshreshtha

Bioactive polysaccharides from plants

Abstract Biologically active polysaccharides isolated from natural sources during the period January 1977 to December 1988 are reviewed. Besides biological activity, the recent techniques used in their isolation, purification and structure elucidation are discussed.

Bacoside A3A triterpenoid saponin from Bacopa monniera

A new triterpenoid saponin, bacoside A3, a constituent of bacosides the saponin mixture of Bacopa monniera, was isolated and characterized. Its structure was established as 3-beta-[O-beta-D-glucopyranosyl(1-->3)-O- [alpha-L-arabinofuranosyl(1-->2) ]O-beta-D-glucopyranosyl)oxy]jujubogenin by chemical and spectral analyses. The cis-isomer of ebelin lactone was also obtained as one of the artefacts of the aglycone and its structure revised.

Flavonoids from Dodonaea viscosa

Abstract An investigation of Dodonaea viscosa afforded a new flavonoid having an isoprenoid side chain along with the seven known flavonoids: 5-hydroxy-3,6,

Triterpenoids and chalcone from Syzygium samarangense

Abstract A new triterpene, methyl 3-epi-betulinate in its native form and 4′,6′-dihydroxy-2′-methoxy-3′,5′-dimethyl chalcone along with ursolic acid, jacoumaric acid and arjunolic acid have been isolated from the aerial parts of Syzygium samarangense.

Streblus asper Lour. (Shakhotaka): A Review of its Chemical, Pharmacological and Ethnomedicinal Properties

Streblus asper Lour is a small tree found in tropical countries, such as India, Sri Lanka, Malaysia, the Philippines and Thailand. Various parts of this plant are used in Ayurveda and other folk medicines for the treatment of different ailments such as filariasis, leprosy, toothache, diarrhea, dysentery and cancer. Research carried out using different in vitro and in vivo techniques of biological evaluation support most of these claims. This review presents the botany, chemistry, traditional uses and pharmacology of this medicinal plant.

Prevention of renal ischemia-reperfusion-induced injury in rats by picroliv

Picroliv is a potent antioxidant extracted from the roots and rhizome of Picrorhiza kurrooa. It has been shown to impart significant hepatoprotective activities, partly by modulation of free radical-induced lipid peroxidation. Lipid peroxidation and reactive oxygen species are associated with tissue injury in post-ischemic acute renal failure. The efficacy of picroliv was assessed in an in vivo model of renal ischemia-reperfusion injury (IRI) in rats at a dose of 12 mg/kg orally for 7 days. The animals were killed at various times after reperfusion. Increased lipid peroxidation and apoptotic cell number reflected the oxidative damage following renal IRI. Picroliv-pretreated rats exhibited lower lipid peroxidation, improved antioxidant status, and reduced apoptosis, indicating better viability of renal cells. Immunohistochemical studies revealed that picroliv pretreatment attenuated the expression of intercellular adhesion molecule-1 in the glomerular region. These results suggested that picroliv pretreatment protects rat kidneys from IRI, perhaps by modulation of free radical damage and adhesion molecules.

Phenolic constituents of Coelogyne ovalis

Abstract The structure of 3′- O -methylbatatasin III, a new bibenzyl of the East Himalayan orchid, Coelogyne ovalis , has been established on the basis of spectral and chemical data. Known 9,10-dihydrophenanthrene derivatives, a bibenzyl and sterols have also been isolated from the orchid.

A xanthone from Swertia chirayita

Abstract The structure of new xanthone from Swertia chirayita has been established as 1,5-dihydroxy-3,8-dimethoxy xanthone (chiratol) on the basis of spectral and chemical evidence. Two other xanthones, i.e. swerchirin (1,8-dihydroxy-3,5-dimethoxy xanthone) and 7- O -methyl swertianin (1,8-dihydroxy-3,7-dimethoxy xanthone) have been isolated. Swerchirin was identified as the hypoglycaemic principle of the plant.

Bacoside A1, A minor saponin from Bacopa monniera

Abstract A new minor triterpene saponin was obtained from Bacopa monniera . Its structure was established as 3- O [α- l -arabinofuranosyl (1 → 3) α- l -arabinopyranosyl]jujubogenin by chemical and spectral studies.

Picroliv preconditioning protects the rat liver against ischemia-reperfusion injury

Cell death following ischemia-reperfusion injury is a major concern in clinical issues such as organ transplantation and trauma. The need to identify agents with a potential for preventing such damage has assumed great importance. We have evaluated the efficacy of picroliv, a potent antioxidant derived from the plant Picrorhiza kurrooa, in protecting against hepatic ischemia-reperfusion injury in vivo. Picroliv was fed to male Sprague Dawley rats in a dose of 12 mg/kg once daily by oral gavage for 7 days prior to hepatic ischemia. Ischemia was induced by occluding the hepatic pedicel with a microaneurysm clip for 30 min and reperfusion was allowed thereafter for varying period (15-120 min) by releasing the microaneurysm clip. Picroliv pretreatment resulted in better hepatocyte glycogen preservation and reduced apoptosis. Reduction in apoptosis was associated with decreased mRNA expression of caspase-3 and Fas. Oxidant induced cellular damage as measured by tissue malondialdehyde (MDA) levels was significantly less following picroliv pretreatment. Both a reduction in neutrophil infiltration and an increased level of intracellular antioxidant enzyme superoxide dismutase possibly contributed to the reduction in tissue lipid peroxidation. Tissue inflammatory cytokines level of interleukin-1alpha (IL-1alpha) and interleukin-1beta (IL-1beta) was also lower in picroliv group. Furthermore, picroliv pretreatment resulted in enhanced proliferating cell nuclear antigen (PCNA) immunoreactivity. These studies strongly suggest picroliv to be a promising agent for ameliorating injury following ischemia-reperfusion.