Eric H. Karunanayake

Effect of Momordica charantia on the glucose tolerance in maturity onset diabetes

Investigations were carried out to evaluate the effect of Momordica charantia on the glucose tolerance of maturity onset diabetic patients. The fruit juice of M. charantia was found to significantly improve the glucose tolerance of 73% of the patients investigated while the other 27% failed to respond.

Oral hypoglycaemic activity of some medicinal plants of Sri Lanka

Investigations were carried out to evaluate the oral hypoglycaemic activity of some Sri Lankan medicinal plants. Approximately 40 plants available locally are reputed to have oral hypoglycaemic activity. Of these, the mostly widely used are (a) Salacia reticulata (Celastraceae) (b) Aegle marmelos (Rutaceae) and (c) Momordica charantia (Cucurbitaceae). Aqueous decoctions of these plants were investigated for their ability to lower the fasting blood glucose level and improve the glucose tolerance in laboratory animals. The results indicate that the aqueous decoctions of all three plants possess significant hypoglycaemic effect. The magnitude of this effect showed time related variation with the three plants. The highest oral hypoglycaemic activity and the maximum improvement of the oral glucose tolerance were associated with the extract of Momordica charantia while the least but significant effects were shown by Salacia reticulata.

Effect of Artocarpus heterophyllus and Asteracanthus longifolia on glucose tolerance in normal human subjects and in maturity-onset diabetic patients

Investigations were carried out to evaluate the effects of hot-water extracts of Artocarpus heterophyllus leaves and Asteracanthus longifolia whole plant material on the glucose tolerance of normal human subjects and maturity-onset diabetic patients. The extracts of both Artocarpus heterophyllus and Asteracanthus longifolia significantly improved glucose tolerance in the normal subjects and the diabetic patients when investigated at oral doses equivalent to 20 g/kg of starting material.

Extra-pancreatic effects of Momordica charantia in rats.

The extra pancreatic effects of the oral hypoglycaemic plant Momordica charantia have been investigated in rats. It was found that the fruit juice of this plant caused an increased glucose uptake by tissues in vitro without concomitant increase of tissue respiration. Oral treatment with the juice prior to a glucose load was found to increase the glycogen content of liver and muscle while it had no effect on the triglyceride content of adipose tissue. Pretreatment of fasted rats with M. charantia fruit juice had no significant effect on the gluconeogenic capacity of kidney slices. Similar results were obtained with kidney slices pre-incubated with M. charantia fruit juice.

Effect of Momordica charantia fruit juice on streptozotocin-induced diabetes in rats.

The oral hypoglycaemic activity of Momordica charantia fruit juice was investigated in rats with streptozotocin-induced diabetes. Oral administration of the juice (10 ml/kg for 30 days) did not show a significant effect, either acute or cumulative, on the ability to tolerate an external glucose load. The glycosylated haemoglobin concentrations were significantly elevated in both juice-treated and untreated diabetic rats and there was no significant difference between the two groups. Viable beta-cells capable of secreting insulin upon stimulation appear to be required for M. charantia to exert its oral hypoglycaemic activity.

Possible hepatotoxicity of Nigella sativa seeds and Dregea volubilis leaves

Aqueous extracts of the seeds of Nigella sativa and mature leaves of Dregea volubilis were administered orally under light ether anaesthesia to male Sprague-Dawley rats for 14 days. Key hepatic enzyme concentrations and histopathological changes in the liver in both treatment groups at the end of 14 days were compared with a control group which received distilled water under identical conditions for 30 days and with a group of normal animals. Serum gamma-glutamyl transferase concentrations were significantly increased in both extract groups while serum alkaline phosphatase concentrations were significantly increased following administration of only D. volubilis when compared with either the control or the normal group. Serum alanine aminotransferase concentrations were significantly increased in both extract groups when compared with the normal group but not with the control group. Degenerative changes in hepatocytes were seen following administration of D. volubilis while consistent significant histopathological changes were not evident following administration of N. sativa.

Effect of Momordica charantia on key hepatic enzymes

The effect of Momordica charantia on certain key hepatic enzymes was investigated using male Sprague-Dawley rats as the animal model. Fruit juice and seed extract of Momordica charantia were administered orally at a daily dose of 1 ml/100 g body weight for 30 days under light ether anaesthesia while the control group received equivalent amounts of distilled water under identical conditions (n = 10 in each case). Serum gamma-glutamyl transferase (P < 0.001) and alkaline phosphatase (P < 0.01-0.001) concentrations were found to be significantly elevated following oral administration of both the fruit juice and the seed extract. Consistent significant histopathological changes in the liver were not observed in either treatment group although the prevalence of dilatation and/or congestion of the central vein sinusoidal system appeared to be twice as high following fruit juice treatment than in the other 2 groups. Thus, Momordica charantia may either contain hepatotoxins capable of causing cellular damage at the molecular level without causing significant histopathological changes or the plant may have an enzyme inducing effect.

Genetic variation in Corynespora cassiicola: a possible relationship between host origin and virulence

Genetic variation of 42 isolates of Corynespora cassiicola, a destructive fungal pathogen of many economically important crop plants including rubber, was investigated using RAPD-PCR analysis. Five genetic groups were identified using RAPD-PCR profiles generated by eight random primers. Results indicate that there is a significant genetic variation among C. cassiicola isolates collected from different host plants. These results should facilitate the development of rubber clones with enhanced resistance against all genetic groups of C. cassiicola.

Isolation of scopoletin from leaves of Hevea brasiliensis and the effect of scopoletin on pathogens of H. brasiliensis.

Scopoletin (7-hydroxy-6-methoxy coumarin) which inhibited the conidial germinationof Corynespora cassiicola was isolated from the uninfected mature leaves ofHevea brasiliensis. Scopoletin was not detected in uninfected immature rubber leaves. The immature leaves produced scopoletin after being infected with C. cassiicola. The concentration of scopoletin in infected leaves was higher than in uninfected mature leaves. Scopoletin also inhibited the conidial germination of other fungal pathogens of H. brasiliensis. However, no correlation was observed between scopoletin accumulation and clonal resistance.

Novel sequence variants and a high frequency of recurrent polymorphisms in BRCA1 gene in Sri Lankan breast cancer patients and at risk individuals

BackgroundBreast Cancer is the most commonly diagnosed cancer among Sri Lankan women. Germline mutations in the susceptibility genes BRCA1 and BRCA2 in hereditary breast/ovarian cancer, though low in prevalence, are highly penetrant and show geographical variations. There have been only a few reports from Asia on mutations in BRCA1/2 genes and none from Sri Lanka.MethodsA total of 130 patients with (N = 66) and without (N = 64) a family history of breast cancer, 70 unaffected individuals with a family history of breast cancer and 40 control subjects were analysed for BRCA1 mutations. All but exon 11 were screened by single strand conformation analysis (SSCP) and heteroduplex analysis. PCR products which showed abnormal patterns in SSCP were sequenced. Exon 11 was directly sequenced.ResultsNineteen sequence variants were found in BRCA1 gene. Two novel deleterious frame-shift mutations; c.3086delT/exon11 (in one patient) and c.5404delG/exon21 (in one patient and two of her family members) were identified. A possibly pathogenic novel missense mutation (c.856T>G/exon 11) and three novel intronic variants (IVS7+36C>T, IVS7+41C>T, IVS7+49del15) were characterised. Ten previously reported common polymorphisms and three previously reported intronic variants were also observed.ConclusionAfter screening of 66 patients with family history and 64 sporadic breast cancer patients, 2 deleterious mutations (c.3086delT and c.5404delG) in two families were identified and two more possibly pathogenic mutations (c.856T>G and IVS17-2A>T) in two families were identified.Data baseBRCA1 - Gene Bank: Accession # U14680 Version # 14680.1