Antihemolytic and antioxidant activities of Biebersteinia multifida

OBJECTIVES

Biebersteinia multifida is a common herb known in Iran. Its roots have been used locally in folk medicine of western region of Iran in the treatment of many diseases. The antioxidant activity and its inhibition of erythrocyte hemolysis were investigated.

MATERIAL AND METHODS

1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihemolytic activity was evaluated by H2O2 induced hemolysis in rat erythrocyte. The total amount of phenolic compounds was determined as gallic acid equivalents and total flavonoid contents were calculated as quercetin equivalents from a calibration curve.

RESULTS

Root had higher phenol contents (80.1 +/- 3.1 mg ml(-1)) and showed highest activity in DPPH radical-scavenging activity (95.9 +/- 3.2 microg ml(-1)). It also showed better reducing power than other parts. In Fe2+ chelating, leaf extract was the most potent (789 +/- 33 microg ml(-1)). Extracts exhibited good H2O2 scavenging in a concentration dependent manner. All extracts exhibited good protection against hemoglobin-catalyzed peroxidation linoleic acid system. In nitric oxide scavenging model, root extract showed the best activity (696 +/- 2.7 microg ml(-1)). Root and leaf extracts contained total phenol and flavonoids contents than other extracts. Tested extracts show weak activity in H2O2 induced hemolysis in rat erythrocyte which was not comparable with vitamin C.

CONCLUSIONS

Biebersteinia multifida extracts exhibited different levels of antioxidant and antihemolytic activities in all tested models. Biological effects may be attributed, at least in part, to the presence of phenols and flavonoids in the extracts.

Alteration by cadmium of rat submandibular gland secretory function and the role of the l-arginine/nitric oxide pathway

The effects of cadmium, l-arginine (nitric oxide precursor) and N(omega)-nitro-l-arginine methyl ester (l -NAME) as a nitric oxide synthesis inhibitor and cotreatment of them on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Fourteen days treatment with 10 mg l(-1)cadmium as cadmium chloride in drinking water caused significant alterations on salivary function. Salivary flow rate, total protein concentration and amylase activity of saliva were decreased while secretion of calcium was increased by cadmium. Two weeks treatment of rats with l -arginine (2.25%) in drinking water caused an increase in submandibular gland weight. Flow rate was reduced by l-NAME. The total protein concentration of saliva was increased by l-arginine while decreased by l-NAME. Calcium concentration of saliva was reduced by l-arginine and increased by l-NAME. Cotreatment of cadmium with l-arginine prevented cadmium-induced reduction of flow rate while l-NAME cotreatment potentiated cadmium-induced reduction of flow rate. l-arginine showed a preventive effect on cadmium-induced decrease of protein concentration and reached control levels. l-arginine potentiated cadmium-induced increase of saliva calcium concentration. It is confirmed that nitric oxide (NO) has a role in salivary gland function. It is also concluded that cadmium inhibitory effects on salivary gland function are modulated by the NO system as it is observed that the cadmium inhibitory effect on submandibular gland function is diminished by l-arginine and extended by l-NAME. Considering the properties of cadmium substitution for calcium in many intracellular events, different types of alterations can be discussed.

L-arginine/nitric oxide pathway and interaction with lead acetate on rat submandibular gland function

The effects of lead acetate, L-arginine (nitric oxide precursor) and L-NAME (nitric oxide synthesis inhibitor) on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally from anaesthetized rats by a micro polyethylene cannula using pilocarpine as secretagogue. Treatment for twenty-eight days with three doses of lead acetate (0.01%, 0.04%, 0.05% w/v) in drinking water caused significant alterations on salivary function. Salivary flow rate was decreased by lead at all doses used. The total protein concentration and amylase activity of saliva were both decreased by lead (0.04% and 0.05%). All doses of lead decreased saliva calcium concentrations. Two weeks' treatment of rats by L-arginine (2.25% w/v) and L-NAME (0.7% w/v) in drinking water also affected the saliva secretory function. L-Arginine caused increase in submandibular gland weight. The saliva flow rate was reduced by L-NAME. The total protein concentration of saliva was increased by L-arginine and decreased by L-NAME. Amylase activity was reduced by L-arginine treatment. Calcium concentration was reduced by L-arginine and increased by L-NAME. Concurrent L-arginine treatment with lead acetate recovered lead-induced reduction of flow rate but L-NAME potentiated it. Concurrent therapy of lead and L-NAME resulted in greater reduction of protein concentration when compared to that of lead. L-Arginine showed a preventive effect on lead-induced decrease of protein concentration. Both L-arginine and L-NAME prevented lead-induced reduction in calcium concentration. It is concluded that nitric oxide plays a role in salivary gland function. Also lead acetate inhibitory effect on submandibular function is somewhat diminished by L-arginine and partially increased by L-NAME. It seems that lead acetate interacts with nitric oxide modulatory role in salivary gland.

Plasma membrane calcium ATPase isoforms in astrocytes

The plasma membrane Ca(2+)-ATPase (PMCA) is an essential component of the machinery responsible for cellular Ca(2+) homeostasis. Together with the Na(+)/Ca(2+) exchanger, the plasma membrane Ca(2+)-ATPase (PMCA) is responsible for the extrusion of Ca(2+) from the cytosol. Although both PMCAs and Na(+)/Ca(2+) exchangers are present in high amounts in the brain, it is thought that only the latter localize to glia. This study investigates whether PMCAs are also present in astrocytes and thus are components of Ca(2+) signalling in this cell type. Membrane proteins and mRNA were isolated from primary cultures of rat cortical astrocytes and C6 glioma cells. PMCA isoforms were investigated with isoform specific antibodies and the splice variant pattern was studied in RT-PCR experiments using specific oligonucleotides. The PMCA1, 2, and 4 isoforms were detected in rat cortical astrocytes, whereas only PMCA1 and 2 were found in C6 cells. While neurons express both the CI and CII splice variants, only the splice variant CI of PMCA1, 2, and 4 was detected in astrocytes. Thus, the PMCA pump is present in mammalian glial cells. These results also show that the amounts of PMCA1 and 4 isoforms in astrocytes are comparable to those found in neurons. In contrast, astrocytes contain smaller amounts of PMCA2. Furthermore, PMCA2 and PMCA4 underwent an evident time dependent up-regulation in astrocytes cultured in vitro.