S. K. Mitra

Antioxidant activity of ethyl acetate soluble fraction of Acacia arabica bark in rats

Objective: To study the antioxidant activity of various extracts and fractions of Acacia arabica by in vitro and in vivo experimental models. Materials and Methods: Various solvent extracts were prepared by Soxhlet extraction. Extract fractionations were done by solvent-solvent extraction and flash chromatographic separation. In vitro lipid peroxidation was carried out by tertiary butyl hydroperoxide -induced lipid peroxidation. The most active fractions were identified and standardized by thin layer chromatography (TLC). In vivo experiments on the most active fraction were carried out with 50, 100, and 150 mg/kg, p.o. doses, in carbon tetrachloride (CCl 4 )-induced hepatotoxicity, in rats. Various biochemical parameters like serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), glutathione (GSH), and lipid peroxidation were estimated. Results: Flash chromatographic fractions 2-6 of ethyl acetate extract exhibited maximum activity with in vitro lipid peroxidation. In vivo evaluation of this active fraction (AA) in CCl4-induced hepatotoxicity for 19 days at a dose of 150 mg/kg offered marked liver protection, which was evident by significant changes in lipid peroxidation, glutathione, superoxide dismutase and catalase ( P <0.01). The treatment also showed significant changes in AST, ALT, and GSH-Px levels ( P < 0.05). At lower doses, the protection was not consistent. Conclusion: The polyphenol rich active fraction of Acacia arabica is a potent free radical scavenger and hepatoprotective and protects TBH-induced lipid peroxidation and CCl 4 -induced hepatic damage.

Antihistaminic and antianaphylactic activity of HK-07, a herbal formulation

Objective: To study the antianaphylactic, antihistaminic and mast cell stabilization activity of HK-07 in experimental animals. Materials and Methods: HK-07 is a polyherbal formulation containing extracts of various plant constituents. The compound HK-07 was evaluated using Wistar rats and Duncan Hartley guinea pigs. The antianaphylactic activity was investigated in rats using the active anaphylaxis model. The effect on mast cell stabilization was performed by ex vivo challenge of antigen in sensitized rat intestinal mesenteries. Antihistaminic activity was studied in guinea pigs using histamine-induced bronchospasm where preconvulsive dyspnea was used as an end point following exposure to histamine aerosol. Dose response studies of HK-07 were conducted at 125, 250, and 500 mg/kg, p.o. in anaphylactic shock-induced bronchospasm in rats. The optimal dose level was used for the remaining experimental models. Results: Treatment with HK-07 at 125, 250, and 500 mg/kg, p.o. showed significant reduction in signs and severity of symptoms (P Conclusion: The findings from various studies reveal that the antihistaminic and antianaphylactic activity of HK-07 may be due to the mast cell stabilizing potential, suppression of IgE, and inhibition of release of inflammatory mediators.

Anti-inflammatory, antioxidant and antimicrobial activity of Ophthacare brand, an herbal eye drops

In the present study, the herbal preparation of Ophthacare brand eye drops was investigated for its anti-inflammatory, antioxidant and antimicrobial activity, using in vivo and in vitro experimental models. Ophthacare brand eye drops exhibited significant anti-inflammatory activity in turpentine liniment-induced ocular inflammation in rabbits. The preparation dose-dependently inhibited ferric chloride-induced lipid peroxidation in vitro and also showed significant antibacterial activity against Escherichia coli and Staphylococcus aureus and antifungal activity against Candida albicans. All these findings suggest that Ophthacare brand eye drops can be used in the treatment of various ophthalmic disorders.

The beneficial effect of OST-6 (OsteoCare), a herbomineral formulation, in experimental osteoporosis

OST-6 (OsteoCare), a herbomineral formulation, was evaluated for its inhibitory effect on the progress of bone loss induced by ovariectomy in rats. Ovariectomized (Ovx) rats were administered with OST-6 at 250 and 500 mg/kg b.wt., orally daily for 90 days. On 91st day, ovariectomized rats showed reduced bone mineral content and increased serum alkaline phosphatase levels, excretion of urinary calcium and pyridinium cross-links levels. Histologically, bone sections revealed narrowed and disappearance of trabeculae and widened medullary spaces. The total numbers of Tartrate-resistant acid phosphatase (TRAP) positive cells were significantly increased both in-vivo and in-vitro methods. OST-6, at a dose of 500 mg/kg, significantly improved bone mineral contents, serum alkaline phosphatase levels, reduced the elevated urinary calcium and pyridinium cross-links excretion, number of TRAP positive cells and reversal of the above mentioned histological features. These results indicate the usefulness of OST-6 in the management of osteoporosis in a natural way through herbal resources.

Pharmacokinetic interactions of Mentat with carbamazepine and phenytoin.

SummaryIn the present study, Mentat, a herbomineral psychotropic preparation, was studied for its pharmacokinetic interaction with the commonly used anti-epileptic drugs, carbamazepine and phenytoin.The interaction of carbamazepine and phenytoin with Mentat was studied in rabbits. Thirty two rabbits were divided into four groups of eight each. Animals of Group I were treated with carbamazepine (50 mg/kg b.wt. p.o.), Group II were treated with carbamazepine (50 mg/kg b.wt. p.o.) +Mentat (500 mg/kg b.wt. p.o.), Group III were treated with phenytoin (50 mg/kg b.wt.p.o.) and Group IV were treated with phenytoin (50 mg/kg b.wt. p.o.) +Mentat (500 mg/kg b.wt. p.o.) for a period of 8 days. On day 0 and day 8, plasma carbamazepine and phenytoin levels were estimated at different time intervals. A simultaneous treatment with Mentat resulted in a significant increase in plasma AUC of carbamazepine as well as well as phenytoin as compared to carbamazepine or phenytoin alone. Cmax and Tmax of carbamazepine and phenytoin also were evaluated. The results suggest that co-administration of Mentat could improve the effectiveness of anti-epileptic drugs due to the increased bioavailability of the latter. However, this has to be done with critical medical supervision to avoid any toxic reactions and preferably with therapeutic drug monitoring (TDM) which could also help in dose optimization.

Pharmacokinetic interaction of Diabecon (D-400) with rifampicin and nifedipine.

SummaryIn the present study, Diabecon (D-400), a herbomineral anti-diabetic preparation, was studied for its pharmacokinetic interaction with the commonly used drugs rifampicin and nifedipine.Interaction of Diabecon with rifampicinThe pharmacokinetic interaction of rifampicin and Diabecon (D-400) was studied in animal models as well as in healthy human volunteers. Twelve rabbits were divided into two groups of six each. Animals in group I were treated with rifampicin (100 mg/kg body weight, p.o.) and group II with rifampicin (100 mg/kg body weight, p.o.) and Diabecon (D-400) (1 g/kg body weight, p.o.) for a period of 8 days. Rifampicin levels in plasma were estimated on day 1 and day 8 at 2, 4, 6 and 8 h after drug administration. On the basis of these findings, a clinical study in 9 healthy human volunteers aged 25–35 years and weighing 50–75 kg was initiated. They were given 450 mg of rifampicin once only on day 1 and from the second day onwards were given 2 tablets of Diabecon (D-400) twice daily for 7 days. On day 9, another dose of rifampicin (450 mg) was given along with 2 tablets of Diabecon (D-400). Blood samples were collected at 2, 4, 6 and 8 h after drug administration on day 1 and day 9 to estimate the rifampicin levels in plasma.Interaction of Diabecon with nifedipineIn another study, 12 rabbits were divided into two groups of 6 each. Group I animals were treated with nifedipine (2.5 mg/kg body weight, p.o.) and Group II animals were treated with nifedipine (2.5 mg/kg body weight, p.o.) and Diabecon (D-400) (1 g/kg body weight, p.o.) for a period of 8 days. On day 1 and day 8, blood samples were collected at 1, 2, 4 and 6 h after drug administration and plasma nifedipine levels were estimated. The results of these three studies revealed that Diabecon (D-400) did not alter the pharmacokinetic profiles of rifampicin and nifedipine.