Upregulation of Glut-4 and PPAR gamma by an isoflavone from Pterocarpus marsupium on L6 myotubes: a possible mechanism of action

The purpose of the present study is to analyse the influence of Pterocarpus marsupium methanolic extract and isolated Pterocarpus marsupium isoflavone on a battery of cellular targets Glut-4, PPAR gamma and PI3 kinase. Pterocarpus marsupium is an anti-diabetic plant indigenous to South India. Sequential extraction performed with different solvents were analysed for glucose uptake activity at each step. Fraction-9 showing maximum glucose activity on glucose uptake was purified by column chromatography and the structure was elucidated as 7-O-alpha-L-rhamnopyranosyl oxy-4'-methoxy-5-hydroxy isoflavone using NMR and mass spectroscopy. The significant glucose uptake showed by Pterocarpus marsupium crude and pure was comparable with insulin and rosiglitazone. Elevation of Glut-4 and PPARgamma gene expression in parallel with glucose uptake supported the in vitro glucose uptake activity of Pterocarpus marsupium methanolic extract and Pterocarpus marsupium isoflavone. The inhibitory effect of cycloheximide on Pterocarpus marsupium methanolic extract and Pterocarpus marsupium isoflavone-mediated glucose uptake suggested that new protein synthesis is required for elevated Glut-4 protein expression. PI3 kinase plays an important role in glucose transport and activated by Pterocarpus marsupium methanolic extract but not the isolated pure isoflavone. Therefore, we postulate that the isoflavone from Pterocarpus marsupium may activate glucose transport by a PI3 kinase independent pathway, which require further analysis.     

Effect of Kaempferol Pretreatment on Myocardial Injury in Rats

The present study was undertaken to evaluate the effect of kaempferol in isoprenaline (ISP)-induced myocardial injury in rats. ISP was administered subcutaneously for two subsequent days to induce myocardial injury. Assessment of myocardial injury was done by estimation of hemodynamic functions, myocardial infarcted area, cardiac injury markers, lipid profile, oxidative stress, pro-inflammatory cytokines and histopathology of heart and liver. Rats pretreated with kaempferol showed reduction in the myocardial infarcted area and heart rate. However, no improvement was observed in change in body weight, mean arterial, systolic and diastolic blood pressure. Kaempferol showed significant decrease in serum LDH, CK-MB, troponin-I and lipid profile. However, highest dose of kaempferol did not reduce the serum triglyceride level. Further, antioxidant enzymes, SOD and catalase, were also higher. However, reduced glutathione, serum SGOT and creatinine did not show any improvement. Kaempferol showed reduction in MDA level. Kaempferol at highest dose showed reduction in pro-MMP-2 expression and MMP-9 level. mRNA expression level of TNF-α was not different in kaempferol-pretreated myocardial injured rats with ISP-alone group. Pretreatment with kaempferol at highest dose showed mild mononuclear infiltration and degenerative changes in heart tissue section of myocardial injured rats. Rats pretreated with kaempferol at higher concentration showed normal cordlike arrangement of hepatocytes with moderate swelling of hepatocytes (vacuolar degeneration) around the central vein. Study suggests that kaempferol attenuated lipid profile, infarcted area and oxidative stress in ISP-induced myocardial injury in rats.     

Pharmacology of alpha/beta arteether--a potential antimalarial drug

Pharmacological studies on alpha/beta arteether (a 30:70 mixture of isomers), a potential drug for the treatment of cerebral malaria, were carried out in experimental animals by giving the drug in arachis oil suspension. The compound appears to be devoid of significant pharmacological activity on the central nervous, cardiovascular and urinary systems. It lacks an anti-inflammatory response in rats up to 50 mg/kg intramuscularly but at 50-200 mg/kg it has some antianaphylactic potential.     

Leishmanicidal compounds from the fruits of Piper longum

One new alkaloid amide, piperlongumide (1) [N-isobutyl-19-(3',4'-methylenedioxyphenyl)-2E,4E nonadecadienamide], and six known compounds with leishmanicidal activity against promastigotes and axenic amastigotes of Leishmania donovani were isolated from the n-hexane fraction of the fruits of Piper longum. The structure of 1 was elucidated by spectroscopic evidences.