Biomedical subjects

Sreejayan

Publications and source records attributed to Sreejayan.

5 recordsLinked to original sources

PubMed2001

Genetic variation and population structure in Oryza malampuzhaensis Krish. et Chand. endemic to Western Ghats, South India.

Oryza malampuzhaensis Krish. et Chand. (2n = 4x = 48; Poaceae, Oryza) is endemic to Western Ghats, South India, and shows a highly localized distribution over a small geographical area in this region. This is the most poorly understood taxon in genus Oryza and is often misidentified as O. officinalis owing to their close morphology. We assessed the nature and distribution of genetic variation among 11 populations of O. malampuzhaensis using random amplified polymorphic DNA markers. The analysis revealed low genetic variation in O. malampuzhaensis. Cluster analysis of pairwise genetic distances of populations revealed three distinct clusters and the grouping of populations largely corresponded to their geographical proximity. Restricted gene flow and a geography-dependent differentiation were evident among populations. The altitude-influenced differences in ecological factors among the natural habitats of the populations seem to be the cause of the geography-dependent differentiation. Genetically isolated smaller populations and a narrow genetic base in O. malampuzhaensis point to its vulnerability to genetic drift and genetic depauperation. Thus O. malampuzhaensis appears to be under the threat of extinction and needs to be conserved by use of suitable methods. The present study also identified molecular markers diagnostic for O. malampuzhaensis.

Altitude↗

PubMed1997

Nitric oxide scavenging by curcuminoids.

Because curcumin, a compound with anti-inflammatory and anticancer activity, inhibits induction of nitric oxide synthase in activated macrophages and has been shown to be a potent scavenger of free radicals we have investigated whether it can scavenge nitric oxide directly. Curcumin reduced the amount of nitrite formed by the reaction between oxygen and nitric oxide generated from sodium nitroprusside. Other related compounds, e.g. demethoxycurcumin, bisdemethoxycurcumin and diacetylcurcumin were as active as curcumin, indicating that the methoxy and the phenolic groups are not essential for the scavenging activity. The results indicate curcumin to be a scavenger of nitric oxide. Because this compound is implicated in inflammation and cancer, the therapeutic properties of curcumin against these conditions might be at least partly explained by its free-radical scavenging properties, including those toward nitric oxide.

Antioxidants↗

PubMed1994

Diminution of singlet oxygen-induced DNA damage by curcumin and related antioxidants.

Curcumin, the natural antioxidant from turmeric, an Indian spice, and its derivatives have significant abilities to protect plasmid pBR322 DNA against single-strand breaks induced by singlet oxygen (1O2), a reactive oxygen species with potential genotoxic/mutagenic properties. 1O2 was generated at 37 degrees C in an aqueous buffer system by the thermal dissociation of the endoperoxide of 3,3'-(1,4-naphthylene)dipropionate (NDPO2). Among the compounds tested, curcumin was the most effective inhibitor of DNA damage followed by desmethoxycurcumin, bisdesmethoxycurcumin and other derivatives. The observed antioxidant activity was both time- and concentration-dependent. The protective ability of curcumin was higher than that of the well-known biological antioxidants lipoate, alpha-tocopherol and beta-carotene. However, the highest protective ability with saturating concentrations of curcumin did not exceed 50%. The ability of curcumin and its derivatives to protect DNA against 1O2 seems to be related to their structures and may at least partly explain the therapeutic and other beneficial effects of these compounds including anticarcinogenic and antimutagenic properties.

Antimutagenic Agents↗

PubMed1994

Curcuminoids as potent inhibitors of lipid peroxidation.

Earlier studies showed that curcumin is a potent inhibitor iron-catalysed lipid peroxidation. Demethoxycurcumin, bisdemethoxycurcumin and acetylcurcumin were tested for their ability to inhibit iron-stimulated lipid peroxidation in rat brain homogenate and rat liver microsomes. Comparison of the results with curcumin showed that all compounds are equally active, and more potent than alpha-tocopherol. These results showed that the methoxy and phenolic groups contribute little to the activity. Spectral studies showed that all compounds could interact with iron. Thus, the inhibition of iron-catalysed lipid peroxidation by curcuminoids may involve chelation of iron.

Animals↗

PubMedDate not supplied

Evidence for oxidant stress in chronic pancreatitis.

BACKGROUND: Oxidant stress leading to lipid peroxidation is reported to be the common link in the pathogenesis of chronic pancreatitis irrespective of etiology. AIM: To look for evidence of lipid peroxidation in duodenal juice in patients with chronic pancreatitis. METHODS: 19 patients with chronic pancreatitis (14 tropical, 5 alcoholic) and 19 age- and sex-matched subjects with abdominal pain without any cause were studied. Contents were aspirated from the second part of the duodenum during gastroduodenoscopy. Malonyl dialdehyde (MDA) levels were measured in duodenal juice by the thiobarbituric acid method. RESULTS: MDA levels were higher in patients than in the control group (mean [SD] 42.6 [17.0] vs 29.2 [11.7] nmol/mL; p < 0.05). On linear and multiple regression analysis, none of the disease factors correlated with duodenal juice MDA levels. CONCLUSIONS: Lipid peroxidation products are increased in patients with chronic tropical and alcoholic pancreatitis.

Adult↗