Supranee Changbumrung

Isolation and characterization of ellagitannins as the major polyphenolic components of Longan (Dimocarpus longan Lour) seeds

Longan (Dimocarpus longan Lour, syn. Euphoria longan Lam.) represents an important fruit in Northern Thailand and has significant economic impact. The fruit is either consumed fresh or as commercially prepared dried and canned products. The canning industry in Thailand produces considerable quantities of waste products, in particular Longan seeds. Because these seeds may be an exploitable source of natural phenolic antioxidants, it was of interest to identify, purify and quantitate the major potential antioxidant phenolics contained therein. The polyphenolic fraction from ground Longan seeds was obtained by extraction with methanol after delipidation with hexane. The hexane extract contained predominantly long-chain fatty acids with major contributions from palmitic (35%) and oleic (28%) acids. The polyphenolic fraction (80.90 g/kg dry weight) was dominated by ellagic acid (25.84 g/kg) and the known ellagitannins corilagin (13.31 g/kg), chebulagic acid (13.06 g/kg), ellagic acid 4-O-α-l-arabinofuranoside (9.93 g/kg), isomallotinic acid (8.56 g/kg) and geraniin (5.79 g/kg). Structure elucidation was performed with mass spectrometry and complete assignment of (1)H and (13)C NMR signals. The methanol extracts exhibited strong antioxidant capacities with an IC(50) of 154 μg/ml for reactive oxygen species attack on salicylic acid and 78 μg/ml for inhibition of xanthine oxidase in the hypoxanthine/xanthine oxidase assay. The extracts were less effective in the 2-deoxyguanosine assay (IC(50)=2.46 mg/ml), indicating that gallates along with ellagic acid and its congeners exert their potential antioxidant effects predominantly by precipitation of proteins such as xanthine oxidase. This was confirmed for the pure compounds gallic acid, methyl gallate, ellagic acid and corilagin.

FLOW RATE AND COMPOSITION OF WHOLE SALIVA IN CHILDREN FROM RURAL AND URBAN THAILAND WITH DIFFERENT CARIES PREVALENCE AND DIETARY INTAKE

The aim of this study was to compare the prevalence of dental caries, dietary composition and whole salivary flow rates together with some of the components of saliva between two groups of children aged 12-16 years, one group from an urban area and the other from a rural area of Thailand. A stratified random samples were taken by class from one schools in each area. The children who had mixed dentition and/or who had migrated from other area of Bangkok and 138 students were selected from a school in a rural area of Khon Kaen in northeast Thailand. Results of completed 24-hour dietary recalls for three consecutive days examining the average nutrient intake were compared looking for differences, if any, between these two groups of children. Dental examinations and whole salivary sampling were also undertaken and possible relationships between some nutrients and certain salivary factors were explored. The prevalence of dental caries was found to be higher in the students living in the urban area. The children in the rural area consumed a higher load of carbohydrate, which came mainly from sticky rice. There was no difference in the protein consumption between the two groups, although the children in the rural area consumed more protein from vegetable sources. The salivary flow rate and the concentrations of fluoride, calcium and phosphate were significantly higher (p < 0.05) in the group from the rural area, while the salivary pH, buffer capacity, concentrations of total protein and urea were higher in the urban area. There was no correlation between nutrient intake and salivary composition in the children from these two areas, which may suggest that dietary nutrients may not have a direct effect on salivary compositions but it was noted that salivary flow rate correlated with salivary urea, albumin and buffer capacity in both areas.

Serum Homocysteine, B12 and Folic Acid Concentration in Thai Overweight and Obese Subjects

This study investigated levels of serum homocysteine, vitamin B12, folic acid, vitamin B6 and vitamin C, in 37 male and 112 female overweight and obese Thai volunteers (body mass index; BMI > or = 25.00), and 23 male and 90 female normal-weight Thai volunteers, who came for a physical check-up at the Out-patient Department, General Practice Section, Rajvithi Hospital, Bangkok from March to October of 2000. Data included anthropometric measurements and waist/hip ratios. All anthropometric variables, except height, were significantly higher for the overweight subjects than for the normal subjects. Statistically significantly higher levels of serum homocysteine were found in the overweight subjects. Serum homocysteine concentrations in overweight and obese males were significantly higher than in overweight and obese females. Serum folic acid and vitamin C in the overweight and obese were found to be statistically significantly lower than in the control subjects. No statistically significant difference in vitamin B12 was found in the overweight and obese subjects compared with the normal control subjects. The medians of serum folic acid and vitamin C concentrations for the overweight and obese males were significantly lower than those of the overweight and obese females. A negative correlation was found between serum folic acid and homocysteine concentrations in all overweight and obese subjects. A significant negative correlation between serum folic acid and vitamin B6 was observed in both male and female overweight and obese subjects. The results of the investigation suggest that homocysteine levels in overweight and obese subjects seem to be caused by insufficient dietary folic acid intake and probably not by B12 deficiency.

Relationship between alpha-2-macroglobulin, anthropometric parameters and lipid profiles in Thai overweight and obese in Bangkok

The aim of this study was to assess anthropometric variables and the lipid pattern in relation to alpha-2-macroglobulin in normal- and over-nourished Thai individuals, to further support the hypothesis that alpha-2-macroglobulin plays a beneficial role in the determination of nutritional status. The study sample comprised of 48 male and 166 female overweight and obese Thai volunteers and 26 male and 81 female normal subjects. The overweight individuals had statistically significant lower alpha-2-macroglobulin (A2M) serum levels. The total serum cholesterol, low density lipoprotein-cholesterol (LDL-C) and triglycerides were significantly higher and high density lipoprotein-cholesterol (HDL-C) lower in the over-nourished group as compared with the normal subjects. The LDL/HDL ratio was slightly but significantly higher in the over-nourished group, but still well below the value of 5 for both groups. In using a stepwise multiple linear regression, the model, which best explained the variation of A2M for all individuals including age, HDL-C, BMI, and gender. The relationship of A2M to the variables under study differed between males and females. For males, a model which includes cholesterol and BMI explained best the variation of the proteinase inhibitor. For the females, the best model includes age, HDL-C and BMI. The role of protease inhibitors has hardly been explored in human epidemiological studies despite its relationship to important public health issues including nutrition, smoking, cancer and cardiovascular diseases. The results of this study further support the hypothesis, that A2M might play a role in the interrelationship of the nutritional status with the occurrence and the prevention of diseases.

Lipid composition of serum lipoprotein in opisthorchiasis.

Lipid composition (i.e. total cholesterol, free cholesterol, cholesteryl ester, triglycerides and phospholipids) in the individual serum lipoprotein fractions (i.e. high-density lipoprotein, low-density lipoprotein and very low-density lipoprotein) were studied in 24 healthy controls and 18 opisthorchiasis patients admitted to the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine. The two groups were similar in age range, sex ration and anthropometric data. Other background data such as blood pressure and alcohol consumption, were also similar in the two groups. All the patients had the habit of eating raw or half-cooked fish. Abnormalities of high-density lipoprotein content in the opisthorchiasis group showed as low cholesterol and cholesteryl ester concentrations but with high triglyceride concentrations. These may result from disturbance of the synthesis of nascent disk high-density lipoprotein or the removal of lipid content in lipoproteins.

The serum protein pattern in primary hepatoma and amoebic liver abscess.

A study of the serum proteins pattern of 30 patients with primary liver cell carcinoma and 11 with amoebic liver abscess was carried out. When compared with controls significant differences were found for both conditions in the values of pre-albumin, transferrin, albumin, haptoglobin, alpha 2-macroglobulin, and alpha 2HS-glycoprotein. In the differential diagnosis of amoebic liver abscess and primary hepatic carcinoma, the estimation of albumin, alpha 1-acid glycoprotein, haptoglobin ceruloplasmin, alpha 2H2-glycoprotein and transferrin was found helpful.

Innovative solutions to nutritional issues in Asia

Asian countries are big, medium and small in size, and comprise industrialised and developing countries. Some are in transitional states, reflected in their types of nutritional problems.