E. R. Jansz

Oral hypoglycaemic activity of Ipomoea aquatica

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.

Bioactivity of cinnamon with special emphasis on diabetes mellitus: a review.

Cinnamon is the oldest spice and has been used by several cultural practices for centuries. In addition to its culinary uses, cinnamon possesses a rising popularity due to many stated health benefits. Out of the large number of cinnamon species available, Cinnamomum aromaticum (Cassia) and Cinnamomum zeylanicum have been subjected to extensive research. Available in vitro and in vivo evidence indicates that cinnamon may have multiple health benefits, mainly in relation to hypoglycaemic activity. Furthermore, the therapeutic potential of cinnamon is stated also to be brought about by its anti-microbial, anti-fungal, antiviral, antioxidant, anti-tumour, blood pressure-lowering, cholesterol and lipid-lowering and gastro-protective properties. This article provides a summary of the scientific literature available on both C. aromaticum and C. zeylanicum. All studies reported here have used cinnamon bark and its products. Although almost all the animal models have indicated a pronounced anti-diabetic activity of both cinnamon species, conflicting results were observed with regard to the few clinical trials available. Therefore, the necessity of evaluating the effects of cinnamon for its therapeutic potential through well-defined and adequately powered randomized controlled clinical trials is emphasized, before recommendations are made for the use of cinnamon as an effective treatment for humans.

Evaluation of the effectiveness of the national vitamin A supplementation programme among school children in Sri Lanka

The Ministry of Health in Sri Lanka commenced a vitamin A supplementation programme of school children with a megadose of 105 micromol (100,000 IU) vitamin A in school years 1, 4 and 7 (approximately 5-, 9- and 12-year-olds, respectively) in 2001. We evaluated the vitamin A supplementation programme of school children in a rural area of Sri Lanka. A cross-sectional study was conducted among children supplemented with an oral megadose of vitamin A (105 micromol; n 452) and children not supplemented (controls; n 294) in Grades 1-5. Children were clinically examined and a sample of blood was taken for serum vitamin A concentration estimation by HPLC. Socio-demographic information was obtained from children or mothers. Supplemented children had a higher proportion of males and stunted children, were younger and lived under poorer conditions as compared to controls. There was no difference in the prevalences of eye signs and symptoms of vitamin A deficiency in the two groups. Supplemented children had higher serum vitamin A concentrations than controls (1.4 (SD 0.49) micromol/l v. 1.2 (SD 0.52) micromol/l). The serum vitamin A concentrations were 1.6 (SD 0.45), 1.4 (SD 0.50), 1.3 (SD 0.44) and 1.1 (SD 0.43) micromol/l in children supplemented within 1, 1-6, 7-12 and 13-18 months of supplementation, respectively. Vitamin A concentrations were significantly greater than controls if supplementation was carried out within 6 months after adjustment. The oral megadose of 105 micromol vitamin A maintained serum vitamin A concentrations for 6 months in school children.

Inhibitory effect of bitter principle of palmyrah (Borassus flabellifer L) fruit pulp on the growth of mice : evidence using bitter and non-bitter fruit pulp

Different cultivars of palmyrah produce mature fruits of differently flavoured palmyrah fruit pulp (PFP). A natural ‘sweet’ (non-bitter) variety exists. Bitter and naturally non-bitter palmyrah fruit pulps showed little difference in total sugars (471 and 543 g kg−1 respectively), estimated by the Nelson method after invertase action, and had total crude flabelliferin contents of 1480 and 1650 mg kg−1 respectively. The flabelliferin profiles on silica gel G60 TLC plates developed using butanol; ethanol; NH3 (7:2:5) differed. Bitter fruit pulp (from Jaffna) contained the bitter flabelliferin F-II as the major component (about 900 mg per kg), while the non-bitter fruit pulp (from Ampara) did not contain F-II but contained the anti-microbial flabelliferin, FB. Incorporation of non-bitter PFP at the 100 g kg−1 level into WHO standard mice-breeding feed resulted in significantly increased (p = 0.00008) weight gain by ICR mice compared with bitter PFP incorporation at the same level in the feed. Weight gain was also significantly higher (p = 0.021) than in the control (WHO standard mice-breeding feed). The study supports the conclusion that the bitter principle, F-II is responsible for reduced weight gain in mice. © 2000 Society of Chemical Industry

A study of the serum carotenoids of eight cases of hypercarotenemia in Sri Lanka

Over-consumption of absorbable carotenoids causes hypercarotenemia. Although hypercarotenemia is detected in Sri Lanka, a detailed study on this condition has not been carried out previously. Two millilitres of venous blood was drawn from hypercarotenemic patients (n=8) and examined by high-performance liquid chromatography for carotenoids and vitamin A. A common high-performance liquid chromatographic pattern in serum was shown by six of the cases with β-carotene (9.9–35.7 µg/dl), β-cryptoxanthin and monohydroxy metabolites collectively (5.3–48.5 µg/dl), and six to eight metabolites of dihydroxy, trihydroxy and polyhydroxy metabolites (22.5–282.1 µg/dl). Vitamin A levels were within the normal range (32–61 µg/dl). However, two cases identified were abnormal. The first of these showed low β-carotene (3.5 µg/dl) and no β-cryptoxanthin and monohydroxy metabolites, but normal dihydroxy, trihydroxy and polyhydroxy metabolites (128.2 µg/dl). However, the vitamin A level was high (75.2 µg/dl). The other case showed high β-carotene (212.3 µg/dl) and β-cryptoxanthin (49.3 µg/dl) but no normal monohydroxy, dihydroxy, trihydroxy and polyhydroxy metabolites. Instead there was an atypical metabolite (343.9 µg/dl). According to the present study, excessive intake of boiled, homogenized carrot and ripe papaw is the main causative factor for hypercarotenemia. Over-consumption of carotenoids-rich plant foods may be complicated in the case of individuals having defects of either the control of the 15,15′-dioxygenase activity or metabolism of carotenoids.

The neurotoxic effect of palmyrah (Borassus flabellifer) flour re-visited.

The neurotoxic effect of palmyrah (Borassus flabellifer L.) shoot flour on Wistar rats has been reported previously by Arseculeratne and co-workers. A deficiency in previous studies was an inadequate description of the methodology, especially on the composition and consumption of test and control feed, and weight gain/losses. This study shows that feeds containing 100% and 70% palmyrah flour result in very little or no feed consumption, and deaths reported could have been interpreted as being due to starvation. A mixture of 50% palmyrah flour and 50% standard breeding feed results in the neurotoxic symptoms such as muscle in-coordination, spasms and immobility of hind limbs reported previously (Arseculeratne and coworkers). These neurotoxic symptoms can be eliminated by heating the palmyrah flour at 80°C for 45 min; that is, detoxification. Attempts were made to reproduce the neurotoxic effect by administering two-fold palmyrah flour extractive compared with that contained in the same flour consumed by experimental rats per day. This did not produce a neurotoxic effects (as reported previously while using rats fed on standard breeding feed). It is interpreted that the nutritional status of the diet influences that manifestation of the neurotoxic effect; the effect being suppressed with a nutritious diet. Studies on the blood enzyme levels of rats showed that while alanine aminotransferase was not affected, aspartate aminotransferase was significantly affected by oral administration of organic solvent-free water and methanol:water (1:1) extractives (P = 0.023 and P = 0.0044), respectively. This study shows that while the reported hepatotoxin is not extracted by these solvent systems, there appears to be a tissue non-specific cellular damage reflected at a subclinical level.

Studies on hypercarotenemia due to excessive ingestion of carrot, pumpkin and papaw

Hypercarotenemia is diagnosed by yellowing of skin. The present study was carried out to study the carotenoids, their metabolites and the vitamin A levels in hypercarotenemics on reporting, changes in serum carotenoids following cessation of feeding carotenoid-bearing foods, and to determine the carotenoids in stools of hypercarotenemics and non-hypercarotenemics. Hypercarotenemic subjects (n = 35) were tested on reporting for a 2-month to 3-month period. Feces from hypercarotenemics (n = 5) and non-hypercarotenemics (n = 8) were extracted and subjected to reverse phase-high-performance liquid chromatography. A questionnaire was administered to parents (n = 35) of these hypercarotenemic children. The serum α- and β carotenoids varied from 119 g/dl to trace and from 149 g/dl to trace respectively, with the monohydroxy metabolites varying from 214 g/dl to nondetectable and polyhydroxy metabolites from 823 g/dl to 7.0 g/dl. Longitudinal studies indicated that serum carotenoid levels declined while vitamin A levels were maintained. α-Carotenes and β-carotenes were not detected in the feces of hypercarotenemics but were present in non-hypercarotenemics.

A Critical Review on Carotenoid Research in Sri Lankan Context and Its Outcomes

As determined by countrywide assessments, vitamin A deficiency is a public health problem in Sri Lanka. Study of carotenoid profile and content could be important to nutritionists as some carotenoids act as precursors of vitamin A. Sri Lanka has a remarkable diversity of carotenoid sources. A number of Sri Lankan sources of carotenoids have been studied by many authors. This study reviews carotenoid research done in Sri Lanka, comparing results which are generally in conflict with a few relevant studies abroad, while focusing on problems of carotenoid research and concluding that it is difficult for a dietician to predict carotenoid intake due to marked biological variation. Therefore, any database on carotenoid covering the entire country has its limitations. Further that even if carotenoid profiles are known using exhaustive sampling, there can be no single method of calculating retinol equivalent (RE) and retinol activity equivalent (RAE) especially as carotenoid uptake and bioconversion could be multifactorially affected and subject to control mechanisms. Therefore, RE and RAE should be calculated differently for different types of plant materials may even be expanded so that a unique calculation depending on plant material and method of cooking.

A review of the neurotoxic effect of palmyrah flour

The present review covers the history of the neurotoxic effect of palmyrah (Borassus flabellifer L). The chemical nature of the active synergists is isomers of a spirostane tetraglycoside containing three rhamnosyl residues and one glucosamine where the position of the NH2 appears to be the difference in the saponins. As neurotoxicity has not been reported in humans consuming palmyrah flour, it is hypothesized that this may be due to one or more of the following: a species effect; the mode of processing flour and cooking palmyrah flour recipes containing these water-soluble and dry-heat decomposable saponin primary amines; frequency of consumption of palmyrah flour-based products; and the nutritive value of other dietary components. It is hypothesized that the Hepatotoxic syndrome as reported previously is due to a collective effect of a number of biologically active compounds, most of which are water-soluble saponins, like neurotoxins.