Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item Anti-inflammatory and analgesic activity in the polyherbal formulation maharasnadhi quathar(Elsevier, 2003) Thabrew, M.I.; Dharmasiri, M.G.; Senaratne, L.Maharasnadhi Quathar (MRQ) is a polyherbal preparation recommended by Ayurvedic medical practitioners for treatment of arthritic conditions. An investigation has been carried out with rats and human rheumatoid arthritis (RA) patients, to determine the anti-inflammatory and analgesic potential of MRQ. Results obtained demonstrate that MRQ can significantly and dose-dependently inhibit carrageenan-induced rat paw oedema (the inhibition at 3h was greater than at 1h after induction of oedema). MRQ could also increase the reaction time of rats in the hot-plate test (by 57% after the first hour of treatment), although it had no effect on the reaction time in the tail-flick test, indicating that MRQ possesses analgesic activity that is probably mediated via a supra-spinal effect.MRQ also exerted a dose-dependent (a) protective effect on heat-induced erythrocyte lysis, and (b) inhibition of 5-lipoxygenase activity. In RA patients, after 3 months of MRQ treatment, there was a marked improvement in the pain and inflammation experienced by the patients as well as in the mobility of the affected joints. From the overall results obtained, it may be concluded that MRQ possesses significant anti-inflammatory and analgesic activities. Alteration in synthesis of prostaglandins and leukotrienes, membrane stabilization and anti-oxidant activity are some of the possible mechanisms through which MRQ mediates its anti-arthritic effects.Item Diuretic activity of leaf and stem decoctions of Anisomeles indica(2003) Dharmasiri, M.G.; Ratnasooriya, W.D.; Thabrew, M.I.Anisomeles indica (Lamiaceae) is a wild perennial herb growing in South and South East Asia. A decoction of leaves and stems of this plant is said to be diuretic but this point has not been verified in a controlled scientific investigation. The aim of the study was to scientifically investigate the diuretic activity of the decoctions of leaves and stems of both preflowering (E1) and flowering (E2) plants. Rats were used for experiments. The results showed that A. indica has powerful diurecti action and justify the use of the plant in traditional medicine in Sri Lanka. It is concluded that only the preflowering plants possessed marked diuretic activity. The selection of proper stage of the plant is vital for the induction of diuresis.Item Water extracts of leaves and stems of pre-flowering but not flowering plants possess analgesic and antihyperalgesic activities in rat(Informa Healthcare, 2003) Dharmasiri, M.G.; Ratnasooriya, W.D.; Thabrew, M.I.According to Sri Lankan traditional medicine, a decoction made from stems and leaves of Anisomeles indica Kuntze (Lamiaceae) possesses analgesic activity. However, the validity of this claim has not been scientifically tested. The aim of this study was to investigate analgesic and antihyperalgesic activities of this plant using a water extract made from the leaves and stems. The water extracts were made from leaves and stems of both preflowering (E1) and flowering plants (E2). E1 showed a dose-dependent analgesic effect up to 6 h of treatment when tested in rats using the hot plate and the tail flick techniques. Further, the analgesic effect of E1 was not accompanied by toxic effects. This effect was neither gender dependent nor dependent on the stage of the estrous cycle. E1 also showed a dose-dependent antihyperalgesic activity in the hot plate test. In contrast, E2 did not show any analgesic effect (500 mg/kg). The analgesic effect produced by E1 was not abolished by naloxone. E1 dose-dependently retarded the amplitude of the spontaneous contractions of isolated dioestrous rat uterus. Further, E1 induced a dosedependent plasma membrane stabilisation effect on rat erythrocytes. Collectively, these observations suggest that the analgesic and antihyperalgesic effects of E1 are mediated from inhibition of COX-1, thus impairing the synthesis of prostaglandins. A change in chemical contents that accompanies flowering could be one possible reason for the inability of E2 to demonstrate analgesic effect.Item Liv. 52 in alcoholic liver disease: a prospective controlled trial(Elsevier, 2003) de Silva, H.A.; Saparamadu, P.A.M.; Thabrew, M.I.; Pathmeswaran, A.; Fonseka, M.M.D.; de Silva, H.J.Liv.52, a hepatoprotective agent of herbal origin, is used empirically for the treatment of alcoholic liver disease in Sri Lanka. We conducted acontrolled trial to assess the efficacy of Liv.52 in patients with alcoholic liver disease. Patients with evidence of alcoholic liver disease attending outpatient clinics were included in a prospective, double blind, randomized, placebo controlled trial. During the trial period, 80 patients who fulfilled inclusion criteria were randomly assigned Liv.52 (cases; n = 40) or placebo (controls) the recommended dose of three capsules twice daily for 6 months. All patients underwent clinical examination (for which a clinical score was computed), and laboratory investigations for routine blood chemistry and liver function before commencement of therapy (baseline). Thereafter, clinical assessments were done monthly for 6 months, while laboratory investigations were done after 1 and 6 months of therapy. There was no significant difference in the age composition, alcohol intake and baseline liver function between the two groups. The two-sample t-test was used to analyze data obtained after 1 and 6 months of therapy against baseline values. There was no significant difference in clinical outcome and liver chemistry between the two groups at any time point. There were no reports of adverse effects attributable to the drug. Our results suggest that Liv.52 may not be useful in the management of patients with alcohol induced liver disease.Item In-vitro studies on the immunomodulatory effects of extracts of Osbeckia aspera(Elsevier, 2001) Nicholl, D.S.; Daniels, H.M.; Thabrew, M.I.; Grayer, R.J.; Simmonds, M.S.J.; Hughes, R.S.Ayruvedic medical practitioners in Sri Lanka use aqueous extracts of the mature leaves of Osbeckia aspera to treat liver disease. The extract has been shown to have hepatoprotective effects in vitro and in vivo, and to have inhibitory effects on the complement system and on in vitro phagocytosis by polymorphonuclear cells. The aim of this study was to investigate the effect of an aqueous extract of Osbeckia on lymphocyte proliferation stimulated by mitogens and antigen. In control peripheral blood mononuclear cells (PBMC), high concentrations of the Osbeckia extract were inhibitory to proliferation stimulated by phytohaemagglutinin (PHA) and tuberculin purified protein derivative (PPD). On stimulation by phorbol myristate acetate and ionomycin (PMA+I) the extract showed stimulation of proliferation at low concentrations (<10 microg/ml) with inhibition at higher concentrations. A similar inhibitory pattern on mitogen/antigen stimulation was seen with PBMC from patients with chronic hepatitis C virus (HCV) infection. These results suggest that the inhibitory agent(s) in the aqueous extract of Osbeckia may have an effect on antigen-presenting cell function. The combined hepatoprotective and immunosuppressive effects of the extract are more likely to be beneficial in acute hepatitis rather than chronic hepatitis viral infection.Item Protection by garlic against adriamycin induced alterations in the oxido-reductive status of mouse red blood cells(Wiley, 2000) Thabrew, M.I.; Samarawickrema, N.A.; Chandrasena, L.G.; Jayasekara, S.The effects of oral garlic supplementation on the activities of (a) the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) and (b) lipid peroxidation, as assessed by malondialdehyde (MDA) production in red blood cells of normal mice and those subject to oxidative stress by chronic administration of the anti-tumour drug adriamycin has been investigated. As expected, adria-mycin administration resulted in a significant increase in MDA generation (by 105.4%) and a decrease in GPX activity (by 23.8%) in the red blood cells. Although garlic had no significant effects on the basal levels of the antioxidant enzymes or MDA generation in red blood cells of normal mice (untreated with adriamycin), at doses of 20 mg/kg or 100 mg/kg, garlic was able to decrease significantly the adriamycin induced changes in the oxido-reductive status of the redblood cells. Thus, on administration of adriamycin to mice fed diets containing 20 mg/kg or 100 mg/kg garlic, the drug-induced increase in MDA generation was 38.2% and 22.5% respectively, less than that produced by adriamycin in mice fed normal diets, containing no garlic (105.4%). Similarly, in mice fed diets providing 20 mg/kg and 100 mg/kg garlic, adriamycin was able to decrease GPX activity by only 15.1% and 7.6% respectively, less than that produced by adriamycin in rats fed normal diets, containing no garlic (23.9%).Item The Oral hypoglacaemic activity of Ipomea aquatica(Elsevier, 2000) Malalavidhane, T.S.; Wickremasinghe, S.M.D.N.; Jansz, E.R.Ipomoea aquatica is a commonly consumed green leafy vegetable in Sri Lanka which is supposed to possess an insulin-like activity [Jayaweera, D.M.A., 1982. Medicinal Plants (Indigenous and Exotic) Used in Ceylon. Part 11. National Science Council, Colombo, Sri Lanka, pp. 99]. Only a little attention has been paid to the therapeutic use of this plant. We studied the oral hypoglycaemic activity of single and multiple doses of I. aquatica in healthy, male Wistar rats after a glucose challenge. There was a significant reduction in the serum glucose concentrations with both single (33%, P<0.0027) and multiple (25%, P<0.02) doses. The optimum dose was 3.4 g/kg while the optimum activity was given 2 h after the administration of the extract. The present study indicates that a boiled, whole extract of I. aquatica exerts an oral hypoglycaemic effect in healthy, male, Wistar rats after a glucose challenge.Item Possible toxicity of a medicinal plant, "Asteracantha longifolia"(University of Colombo, 2000) Fernando, R.M.; Wickremasinghe, S.M.D.N.; Thabrew, M.I.;Asteracantha longifolia is a medicinal plant that is extensively used for the treatment of diabetes mellitus in Sri Lanka. Experiments were carried out to evaluate any possible toxicological effects mediated by the long-term administration of an aqueous extract of this plant. Investigations with Asteracantha longifolia showed that the aqueous extracts of this plant had no adverse effects on the histology of liver, heart, lung, kidney, intestine and pancreas, on liver function, haematological parameters (haemoglobin concentration, red blood cell count, white blood cell count and packed cell volume) or on the reproductive ability of rats.Item Cytoprotective effect of Osbeckia aspera against oxidative damage to HepG2 cells(Lippincott Williams and Wilkins, 1998) Thabrew, M.I.Aqueous extracts of the leaves of plants of the Osbeckia family are used in Sri Lanka for treatment of liver disease. The extract contains antioxidant compounds and in vitro experiments were performed to determine the antioxidant effects of an extract of Osbeckia aspera. The plant extract significantly protected HepG2 cells against the peroxidating effects of cumene hydroperoxide and tert-butyl hydroperoxide. The protection against cell damage from both hepatotoxic compounds was similar to that of silymarin, but not asgreat as that shown by (+)-catechin. Antioxidant compounds in Osbeckia aspera may be an important mechanism responsible for the in vivo hepatoprotective activity of this plant.Item Protection against galactosamine and test-butyl hydroperoxide induced hepatocyte damage by Melothria maderaspatana extract(Wiley, 1995) Thabrew, M.I.; Gove, C.D.; Hughes, R.D.; McFarlane, I.G.; Williams, R.The aqueous extract of Melothria maderaspatana is used by traditional medical practitioners to treat jaundice in man. The effect of Melothria maderaspatana extract on damage induced in freshly isolated rat hepatocytes by D-galactosamine and tert-butyl hydroperoxide (TBH) has been investigated. On incubation of hepatocytes with galactosamine or TBH in the presence of the plant extract, a significant dose-dependent protection against hepatocyte damage was observed, with maximum protection at a concentration of 500 g/mL. At this concentration the galactosamine-induced release of lactate dehydrogenase (LDH) and aspartate amino-transferase (AST) were reduced by 40.7 percent + or - 4.2 percent and 37.7 percent + or - 6.1 percent respectively, compared with control incubations. The TBH-induced lipid peroxidation (estimated from malondialdehyde production) was decreased by 26.0 + or - 3.7 percent together with a 38.4 percent + or - 4.4 percent and 40.8 + or - 7.6 percent reduction in the release of cellular LDH and AST respectively into the incubation medium. On post-treatment with the plant extract the protective activity was found to decrease with increase in time of exposure of the cells to either of the toxins. The direct protective effects of Melothria extract on hepatocytes support the use of this plant as a herbal remedy.