Showing papers in "Vidyodaya Journal of Science in 2010"

Some nutritional aspects of Lasia spinosa (kohila)

Abstract: Lasia spinosa (local name - kohila) is a stout, marshy plant with a creeping spiny rhizome. The tender leaves and rhizomes are used as a vegetable and are recommended for a variety of diseases in Ayurvedic medicine. The present study was carried out to determine the total antioxidant activity of Lasia spinosa rhizome and the contribution to antioxidant activity from the polyphenol fraction and ascorbic acid and the dietary fiber content (insoluble & soluble). Rhizomes 01=6) of Lasia spinosa were collected from six different markets in the locality near the university. According to the results obtained from the study, Lasia rhizome possessed a wide-ranging antioxidant capacity. A total antioxidant activity of 145.0 - 957.0 |^mol/g TEAC on a wet weight basis was observed. The contribution from polyphenols to the antioxidant activity ranged from 14% - 48%. In addition to polyphenols, ascorbic acid also contributes to the total antioxidant activity (34% - 56%). The rhizome is a rich source of dietary fiber with 40% - 75% of total dietary fiber on dry weight basis, (7.2% - 7.5% on fresh weight basis) constituting 35% - 60% and 4% - 18% of insoluble and soluble fiber respectively. The above antioxidants could act independently or synergistically with fiber, since Lasia spinosa is a rich source of dietary fiber to reduce the adverse effects of various diseases. Thus kohila rhizome can be considered as a valuable functional food from the viewpoint of its antioxidant and dietary fibre content. Key words : Lasia spinosa, antioxidant activity, polyphenols, ascorbic acid, dietary fiber Vidyodaya J. of Sci.. (2009) Vol. 14, pp 59-64

A New Point Estimator for the Median of Gamma Distribution

Abstract: In this paper, we consider the problem of estimating the median of a gamma distribution. We introduce a new point estimator based on an approximation that we derive for the median of a gamma distribution. We compare the new estimator with two conventional estimators, namely the sample median and the maximum likelihood estimator (mle). Comparison is based on the amount of computations required to calculate the estimates and the root mean square errors of the estimators. The new estimator is shown to be 'optimum' with respect to these two criteria. Keywords and phrases: gamma distribution, median, point estimate, maximum likelihood estimate, moment estimate. Vidyodaya J. of Sci.. (2009) Vol. 14, pp 95-103

Oviposition deterrent and insecticidal activities of some indigenous plant extracts against the rice moth, Corcyra cephalonica (Stainton)

Abstract: Methanol extracts of eighteen plants belonging to thirteen families were evaluated under laboratory conditions for their effects on the oviposition and larval mortality of the rice moth, Corcyra cephalonica. Each plant extract was tested at a concentration of 12g/l. All the extracts tested showed significant variations in toxic and oviposition deterrence against C. cephalonica when compared with the control. However, among the eighteen plants evaluated, leaf and seed extracts of Azadiracta indica and the seed extract of Piper nigrum were found to be the most effective causing 100% larval mortality. This was followed by leaf (81%) and seed (84%) extracts of Annona squamosa. Conversely, the seed extract of Annona muricata was the least toxic exhibiting only 2.83 % mortality. More over, maximum ovipostion deterrence was observed with P. nigrum followed by A. indica and A. squamosa. None of the plant extracts had any adverse effects on the viability of maize seeds. When percentage mortality and ovipositional deterrence were considered as indices of insecticidal activity, R nigrum and A. indica together with A. squamosa proved to be the most effective plant materials that could be used as grain protectants in controlling infestations of C. cephalonica. Key words: plant extracts, Corcyra cephalonica, rice moth, larval mortality, oviposition deterrence Vidyodaya J. of Sci.. (2009) Vol. 14, pp 143-150

Aflatoxin contamination in peanuts commercially available in Sri Lanka

Abstract: Peanut is one of the oil seeds available in Sri Lanka. Peanuts and peanut products are considered as popular food items among all age groups of population, especially in urban areas. People prefer to buy peanut based food items as snacks. Peanut is shown to be a good substrate for the growth of Aspergillus sp. and for the production of aflatoxins. Aflatoxins are potent teratogenic, mutagenic, and carcinogenic mycotoxin proven to be contained in food and feed. Present work was carried out as a preliminary study to determine the level of aflatoxin contamination in commercially available roasted and fried peanut samples collected from venders in Colombo city, Sri Lanka. Samples were tested for aflatoxins by the CB method of the Association of Official Analytical Chemists. Degree of aflatoxin contamination was determined by densitometric evaluation. For the method validation of aflatoxin analysis, two extraction and cleanup procedures were performed. Chloroform/water extraction and Sep Pac cartridge clean up procedure were selected as the most reliable methods. Results of the study showed that 6.6 % of the tested peanut samples were moderately contaminated (12.5 ppb) and the remaining was fallen into the category of uncontaminated according to the FAO and WHO standards. Overall result of the study showed that the samples were not significantly contaminated and unnecessary doubt on aflatoxin contamination is not needed. However, effective constant monitoring, surveillance and control programs on aflatoxins contamination are important to protect consumers from aflatoxin toxicities. Therefore, screening programs which prevents unsuitable products entering to the market are recommended to evaluate the contamination. Key words: Peanut, aflatoxin, method validation, Aspergillus flavus, A. parasiticus Vidyodaya J. of Sci.. (2009) Vol. 14, pp 151-159

Studies on a hyper-haemolytic compound of palmyrah flour (Odiyal)

Abstract: Palmyrah (Borassus flabellifer L.) flour (Odiyal) is well known to contain toxins. A new saponin was isolated from the medium pressure liquid chromatography (MPLC) fraction between 90% - 100% MeOH:EtOAc extract and crystallized. On subjecting to Micro-Time of Flight (Micro-TOF) mass spectrometry it was found to have a molecular weight of 1534, containing the common steroidal aglycone of odiyal of molecular weight 414, 5 ramhnosyl and 1 glucosyl residues. The first fragment corresponding to MW 228 may be an uncommon fatty acid derivative. Testing for haemolysis on human red blood cells (RBC) showed the compound to be hyper-haemolytic with a haemolytic index 37 fold that of the flabelliferin B (F B ) which had been the previously reported steroidal saponin RBC haemolyser with highest activity from palmyrah. Key words: Palmyrah, odiyal, hyper-haemolytic agent, steroidal saponin derivative Vidyodaya J. of Sci.. (2009) Vol. 14, pp 79-84

Oral Hypoglycaemic Effect of Canthium coromandelicum Leaf Extract on Wistar Rats

Abstract: Canthium coromandelicum (Burm. F), are trees found in dry scrub and monsoon forests in Sri Lanka and Southern India. Immature leaves have been a traditional food accompaniment to rice among the people living in Sri Lanka where the plant is frequently found. The present study was designed to investigate the possible oral hypoglycaemic activity of the leaf extract in rats. Percentage decreases of serum glucose levels of 15.4 % - 25.7 % were observed at doses of 15-30 g/ kg body weight following a glucose challenge. This is indicative of acute hypoglycaemic (anti-hyperglycaemic) activity of the leaf extract. Oral glucose challenge on the 8 th and 15 th day following repeated administration of leaf extract (20g/kg body weight) for 7 and 14 days did not suppress the fasting or the post-prandial serum glucose levels. It is concluded that the observed acute hypoglycaemic (anti-hyperglycaemic) effect is possibly due to inhibition or reduction of intestinal glucose absorption mediated by soluble dietary fibre (SDF; 1.2% DM) and pectin (38% of SDF) in the leaf. This will explain the absence of a chronic effect. This study provides evidence for its traditional recommendation as a functional food in diabetes. Key words: Canthium coromandelicum, antihyperglycaemic activity, normoglycaemic rats, aqueous extract Vidyodaya J. of Sci.. (2009) Vol. 14, pp 53-57

Efficacy of three plant species on the mortality and food consumption of Epilachna vigintioctopunctata

Abstract: The Evaluation of Azadiracta indica (Neem), Annona reticulata, (Custard apple) and Annona squamosa (Sugar apple) under laboratory conditions showed their potential as antifeedants and insecticides for the control of Epilachna vigintioctopunctata. Methanol extracts of all three plants elicited a highly significant reduction in food consumption from the Epilachna larvae. When compared with the other two plant extracts, A. squamosa produced a very strong antifeedant effect on the larvae at all concentrations tested. At the highest concentration (20.0g/l)., none of the larvae consumed leaf disks treated with A. squamosa extract at all, but all larvae died immediately after they were introduced to the test medium, indicating a strong contact toxic effect on the larvae. With all the plants, the food consumption decreased with the increase of the concentration. Among the three plants tested, A. squamosa was the most effective against the Epilachna larvae causing significantly very high mortality even after 24 hours. A. indica extract on the other hand, elicited a much more delayed toxic action in the larvae. When treated with extracts of A. indica, a positive relationship was observed between larval mortality and concentration of extracts and also between larval mortality and time. Larval mortality increased with the increase of concentration and also with time. However, no larval deaths were recorded for 4 days with any concentration tested and 100% mortality was recorded on the 12 th day after treatment at the highest concentration (20.0g/l). Key Words: Epilachna vigintioctopunctata, Plant extracts, Larval mortality, Antifeedant activity Vidyodaya J. of Sci.. (2009) Vol. 14, pp 167-176

Canthium coromandelicum leaf as a functional food

Abstract: Canthium coromandelicum (Sinhala-Kara) leaf is consumed in the form of a 'Sambal' and 'Malluma' mixed with coconut. It shows a hypocholesterolaemic effect on Wistar rats which is due to high molecular weight pectin (up to 2 million Daltons) as determined by Sepharose (2B) gel chromatography and present in a content of 1.8-3.4% on dry weight. Together with its mild hypoglycaemic effect reported previously its hypocholesterolaemic effect is now hypothesized to be due to the effect of high molecular weight pectin. It is postulated that the leaf would make a good functional food. Key words: Canthium coromandelicum, Hypocholesterolaemic effect, Pectin Vidyodaya J. of Sci.. (2009) Vol. 14, pp 105-109

Avifaunal species richness and diversity at the premises of the University of Sri Jayewardenepura, Nugegoda, Sri Lanka

Abstract: A study on avifaunal species richness and the species diversity at the University of Sri Jayewardenepura, Nugegoda, Sri Lanka was carried out with the objective of identification of the bird species inhabiting the university, using fixed radius point count method from August 2004 to March 2005. Seven circular plots with a 50m radius and their centers at least 150m apart were selected to represent all the habitat types available at the University. Avifaunal populations in those seven plots were recorded from 6:00 hrs to 9:00 hrs, four times each month. Thirty two bird species belonging to eight orders and twenty three families were recorded during the study period. Those included three migratory bird species, Forest wagtail (Dendronanthus indicus), Asian paradise-flycatcher (Terpsiphone paradisi}, Grey wagtail (Motacilla cinered) and one endemic species Crimson-fronted barbet (Megalaima rubricapilla rubricapilla). Four bird species, Rose ringed parakeet (Psittacula krameri), Red vented bulbul (Pycnonotus cafer cafer) and Yellow billed babbler (Turdoides affinis taprobanus} were recorded in all seven sites. Endemic Crimson fronted barbet was recorded only in the site which had canopy trees. Seventeen avian species were recorded in all the months from August 2004 to March 2005. There was no significant difference of the species diversity among months. Site with Casuarina equisetifolis had the highest species richness of 25 and site covered with grass had the lowest species richness of 11. Relative abundance indicated that Common myna was the most common bird followed by the Red-vented bulbul. Long-billed sunbird and Indian pond heron were the least common birds followed by Oriental white-eye and Crimson-fronted barbet. Although the University is situated 2 km away from the well known aquatic bird sanctuary, Bellanwila - Attidiya marsh, no aquatic birds were recorded. The University provides habitats for thirty two avian species despite the fact that it is situated in a highly urbanized area, and thus warrants step to protect them. Keywords: Avifauna, species, richness, diversity Vidyodaya J. of Sci. (2009) Vol. 14, pp 41-51

Activity budgets and habitat preferences of land monitor, "thalagoya" Varanus bengalensis in a residential area

Abstract: A study on habitat use and activity budget of the land monitor Varanus bengalensis was conducted from August 2004 to February 2005 inside the university premises of Sri Jayewardenepura, Nugegoda, Colombo, Sri Lanka. Activity index of the land monitors was significantly high for the time period of 0900 to 1200 hrs (2.22±0.51). Activity patterns varied during the day but remained constant among months. Time spent on basking was highest between 0900 to 1200 hrs and foraging was highest between 1200 to 1500 hrs (p<0.05, x=187. 332). Stones were used significantly more than the other habitat types for basking while wet grounds and dumping sites were used for foraging activities. There was a significant correlation between the individual count and the ambient temperature (P>O.05, Z=2.645). Walkers, sweepers, dogs and cats did not disturb the land monitors but vehicles disturbed them. Findings of the present study suggest that the best time for locating the land monitors are from 0900 to 1200 hrs and that providing suitable basking and foraging sites and making certain areas off lim its to vehicles will be helpful in increasing the land monitor populations in urban areas.

Spoilage after cooking of some rice varieties commonly consumed in Sri Lanka

Abstract: Rice once cooked is perishable. In the present study we investigated cooked rice spoilage of common rice varieties in Sri Lanka. The study was further extended to compare the effect of clay and aluminium pots on the cooked rice spoilage and to study the potential to put off cooked rice spoilage in the traditionally used botanicals rampe (Pandans latifolia), curry leaves (Murraya koenigii} and turmeric (Curcuma domestica). One Gram positive bacteria was isolated and identified as Bacillus cereus. In cooked rice, the total count of Gram positive bacteria increased with time while the total count of Gram negative bacteria decreased. When inoculated separately to sterilized rice, the Gram positive bacteria multiplied to a significantly greater number (p Key words : Rice spoilage, Gram positive bacteria, Bacillus cereus, anti­bacterial effect, Pandanus latifolia Vidyodaya J. of Sci.. (2009) Vol. 14, pp 131-141

Species richness and ecological characterization of wood-inhabiting agaric fungi on home-garden logs in semi-urbanized areas in Colombo suburbs

Abstract: Agaric fungi found on fallen logs of different wood species in home gardens were studied. Species richness and their substrate preferences were determined by examining the fruit body formation, habit and frequency of their appearance on the different wood. The effects of temperature, rain and moisture on fruit body formation were also correlated. During the study period 36 fungal species were identified as wood-inhabiting agaric fungi on 25 home-garden wood species. Frequency of appearance of fruit bodies was directly related to the rainfall pattern, but amount of rainfall, temperature and relative humidity did not show any relationship. The highest species richness was found on Cocos nusifera, recording 16 agaric species. Artocarpus heterophyllus, Tectonia grandis, Swietenia. macrophylla and Vitex altisima showed resistance to macrofungal attack. Schizophyllum commune was observed on 16 wood species as the commonest agaric species while 17 agaric species recorded their preference to one particular wood species. Since there was a high diversity of wood decaying agaric species inhabiting most of the wood species in this semi-urbanized area, it is possible to cause considerable damage to valuable wood and wood products in service resulting in economic loss. Key words: agaric fungi, fallen logs, species richness, wood-decay Vidyodaya J. of Sci.. (2009) Vol. 14, pp 177-187

A novel water soluble carotenoid derivative from palmyrah ( Borassus flabellifer L) fruit pulp

Abstract: A water soluble carotenoid derivative is reported for the first time. The source was the fruit pulp of palmyrah (Borassus flabellifer L). Using the normal carotenoid extraction procedure the yellow pigment was found to be unextractable into petroleum ether and diethyl ether. Subjecting the freeze dried water extract to naringinase hydrolysis resulted in the release of glucose and small amount of rhamnose as detected by thin layer chromatography (Tic). Enzymic hydrolysis resulted in the pigment becoming petroleum ether soluble. The spectrum was typical of carotenoids. All parameters measured changed on enzymic hydrolysis viz., A, max from 413, 443,479 to 401, 426, 462; R f on Tic on 5% methanol in toluene from 0 to 0.89; high performance liquid chromatography (HPLC) retention time in the carotenoid solvent system (acetonitrile: methanol: tetrahydrofuran 58:35:7) from 4 to 28 min; while the water soluble carotenoid had no epoxy groups, after hydrolysis, in the epoxy-furanoid rearrangement and fuming HC1 test gave two epoxy groups which was compatible with the R f values on Tic and the retention time on HPLC. The product configuration was trans. Since the enzymic hydrolysis used was to split glycosidic bonds, the parent aglycone is likely to have had two hydroxy groups, which during or after glycosidic cleavage resulted in the formation of two epoxy groups. Since the raw material (palmyrah fruit pulp) contains several underivatised carotenoids, glucose and rhamnose as well as glycosyl and rhamnosyl transferases, which normally act on p-sitosterol to form glycosides, it is hypothesized that the precursor carotenoid acts as a substrate analog of P-sitosterol. The water soluble derivative or synthetic analogs could have commercial applications as a food colour in the beverage industry. Key words: Carotenoid; Water soluble; Glycoside; Palmyrah; Borassus flabellifer Vidyodaya J. of Sci.. (2009) Vol. 14, pp 111-116

A Review of Carotenoid Analysis Techniques in the Sri Lankan Context and Solution to Some Problems Therein

Abstract: Carotenoid analyses results are subject to much variation. In this study problems of sampling, extraction, chromatography spectral data, and chemical tests are discussed together with in-vitro bioaccessibility In addition, problems in the in-vitro trolox equivalent antioxidant capacity assay will be discussed. Identifying carotenoids requires uv/vis spectra, spectral databases, chromatographic behavior on thin layer chromatography (TLC), high performance liquid chromatography (HPLC), open column chromatography (OCC) and chemical tests all of which must be used in conjunction. Quantification can be done by OCC and HPLC but correction factors are needed in the latter. Vidyodaya J. of Sci.. (2009) Vol. 14, pp 1-13

Antibacterial activity of extracts of pericarp of Garcinia mangostana

Abstract: Pericarp of the fruit of Garcinia mangostana L is used for the treatment of skin infections, wounds and diarrhea in indigenous medicine of Thailand, India, Sri Lanka and Myanmar. In the present study, the inhibitory effect of extracts of pericarp ofGarcinia mangostana on bacterial growth was investigated. An inhibitory activity was exhibited by methanolic extract against Gram-positive bacteria tested (Bacillus subtilis., Staphylococcus aureus. and Streptococcus faecalis) whilst no inhibitory effect was observed against Gram -negative bacteria such as Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) was determined using serially diluted extract with methanol on nutrient agar. After 24 hours of incubation at room temperature, the lowest concentration of the extract which inhibited the visible bacterial growth was recorded as MIC. The MIC of the extract was 0.0005 glml against Bacillus subtilis and Staphylococcus aureus while 0.005g1ml against Streptococcus faecalis. Crude extract was fractionated with ether and ethyl acetate successively to obtain ether-soluble and ethy I acetate soluble phenolics respectively. These two fractions were found to possess inhibitory effect on growth of Bacillus subtilis., Staphylococcus aureus. and Streptococcus faecalis. Chromatographic analysis of the two fractions showed the presence of several phenolic compounds.

Preparation and storage of Pinnatu destroys the hypocholesterolaemic effect of palmyrah fruit pulp

Abstract: It has been suggested that the hypocholesterolaemic effect of palmyrah fruit pulp (PFP) is brought about by the soluble dietary fibre which is dominated by pectin. However, this has not been conclusively proven. The present publication describes studies to determine if pinnatu (dried PFP, fruit leather) could possess any hypocholesterolaemic activity. Neither pinnatu (prepared by drying PFP in layers as in the conventional method) nor pectin extracted from pinnatu (incorporated at a double dose to above experiment) could indicate any hypocholesterolaemic effect on normal Wistar rats. Pinnatu pectin on separation on Sepharose gel chromatography showed a high elution volume pattern indicating the hydrolysis of pectin while processing. Further it was found that pinnatu contains exopectinase activity. Subsequently, pinnatu was prepared using a modified method in order to minimize the hydrolysis of high molecular weight pectin. The Sepharose gel chromatography pattern of the isolated pectin of the modified pinnatu showed no degradation of pectin. However, after storing (6-7 months), this pinnatu pectin showed a slight shift to the lower elution volume indicating slight hydrolysis. On feeding Wistar rats with this pinnatu showed no hypocholesterolaemic effect (p=0.85). It is concluded that the preparation and storage of pinnatu destroys the hypocholesterolaemic effect of PFP. High molecular weight pectin may not be the major factor for the hypocholesterolaemic effect of PFP. It is also possible that storage of pinnatu causes not only chemical but also physical changes in pectin. Keywords: Pinnatu, hypocholesterolaemic effect, Pectin Vidyodaya J. of Sci.. (2009) Vol. 14, pp 85-93

Diurnal avifaunal diversity and density along the Bolgoda Canal of the Bellanwila- Attidiya Marsh, Western Sri Lanka

Abstract: Diurnal Avifaunal species richness, diversity and density was studied along the Bolgoda Canal in BellanwilaAttidiya Marsh from June 2005 to February 2006 using the fixed distance line transect method. Six line transects (length 500m each) totaling 3.00 km, which provided the maximum visibility of the Bolgoda canal was marked along the canal bank using a GPS. All birds seen within one hundred meters on either side of each transect were recorded for each month from June 2005 to February 2006. A total number of 107 individuals belong to 53 bird species, thirteen orders and thirty one families were recorded during the study period. The globally endangered Spot Billed Pelican (Pelecanus philippensis) and four migratory species Common Sandpiper (Actitis hypoleucos), Eurasion ThickKnee (Burhinus Odicnemus), Gull Billed Tern (Gelochelidon niloticai, and Asian Paradise Flycatcher (Terpsiphone paradis i) were among them. Diversity and density indices were significantly different among months (ANOVA, F=4.24, p

Lipid composition of skin and muscle of the Indo-Pacific sailfish, Istiophorus platypterus

Abstract: The fat contents and fatty acid profiles of the skin, dorsal muscle, ventral muscle and belly flap of the Indo-Pacific sailfish, Istiophorus platypterus (Thalapatha) were determined. Three fish samples per month were obtained from Pitipana, Negambo landing site over a period of eight months (August 2007- March 2008). The mean fat content of the edible portion of I. platypterus, was lower than 5%. Therefore I. platypterus can be considered as a low fat fish (low 10%). The percentage content of fat in the skin and muscles were as follows; skin (6.52 ±0.53), ventral muscle (2.52± 0.19), dorsal muscle (1.79± 0.27), belly flap (3.91± 0.15). The composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) were as follows; skin 56%, 39%, 44%; ventral muscle 44%, 46%, 33%; dorsal muscle 39%, 42%, 24%; Belly flap 52%, 34%, 38%. The proportion of eicosopentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) in the fat of skin (2.31%, 7.23%) and belly flap (2.06%, 5.36%) were significantly high (P Key words: Lipid composition, docosapentaenoic acid, eicosapentaenoic acid, Istiophorus platypterus Vidyodaya J. of Sci.. (2009) Vol. 14, pp161-166

Evaluation of trends in integration of organic farming system into potato farming: Soil fertility and productivity

Abstract: Application of chemical fertilizers is the general fertilization practice in the potato (Solanum tuberosum L.) farming system. Present trend is application of animal manure along with reduced rates of chemical fertilizers in potato farming. Precise impacts of incorporation of organic farming system into conventional farming system was evaluated by means of potato productivity and soil fertility using major potato growing fields in Sri Lanka. Three clusters were selected on the basis of different fertilizations, and physical and chemical properties of soils were analyzed. Productivity and production costs of potato were also assessed in all clusters from 2003 to 2005. Major nutrient levels were higher than the required amounts for potatoes in all clusters in both manure amended systems (MASs) and manure unamended systems (MUSs), but there was no significant difference in major nutrient levels between MASs and MUSs. However, the tuber yield was not affected by incorporation of organic farming system and showed a strong positive linear correlation with sand : clay ratio of soil. Animal manure amended systems reduced the potato production costs by 3.0-7.2% without affecting the tuber yield, and thereby increasing the benefit to cost ratio. Key words: Land classes, chemical fertilizer, organic farming, potato yield Vidyodaya J. of Sci.. (2009) Vol. 14, pp 15-29