Bioassay-guided fractionation and identification of α-amylase inhibitors from Syzygium cumini leaves.

CONTEXT: Pancreatic α-amylase and α-glucosidase inhibitors serve as important strategies in the management of blood glucose. Even though Syzygium cumini (L.) Skeels (Myrtaceae) (SC) is used extensively to treat diabetes; scientific evidence on antidiabetic effects of SC leaves is scarce. OBJECTIVE: SC leaf extract was investigated for α-amylase inhibitory effect and continued with isolation and identification of α-amylase inhibitors. MATERIALS AND METHODS: Bioassay-guided fractionation was conducted using in vitro α-amylase inhibitory assay (with 20-1000 µg/mL test material) to isolate the inhibitory compounds from ethyl acetate extract of SC leaves. Structures of the isolated inhibitory compounds were elucidated using 1H NMR and 13C NMR spectroscopic analysis and direct TLC and HPLC comparison with authentic samples. Study period was from October 2013 to October 2015. RESULTS: An active fraction obtained with chromatographic separation of the extract inhibited porcine pancreatic α-amylase with an IC50 of 39.9 µg/mL. Furthermore, it showed a strong inhibition on α-glucosidase with an IC50 of 28.2 µg/mL. The active fraction was determined to be a 3:1 mixture of ursolic acid and oleanolic acid. Pure ursolic acid and oleanolic acid showed IC50 values of 6.7 and 57.4 µg/mL, respectively, against α-amylase and 3.1 and 44.1 µg/mL respectively, against α-glucosidase. DISCUSSION AND CONCLUSIONS: The present study revealed strong α-amylase and α-glucosidase inhibitory effects of ursolic acid and oleanolic acid isolated from SC leaves for the first time validating the use of SC leaves in antidiabetic therapy.

Chemical characterization of gallstones: an approach to explore the aetiopathogenesis of gallstone disease in Sri Lanka.

INTRODUCTION: Records on gallstones and associated ailments in Sri Lankan community are scarce, despite frequent detection of gallstone disease. Identification of the chemical composition of gallstones in the local setting is important in defining aetiopathogenic factors which in turn are useful in implementing therapeutic and preventive strategies. This study aimed to describe the chemical composition of gallstones and the socio-demographic factors of a cohort of Sri Lankan patients with gallstone disease. MATERIALS AND METHODS: Data on clinical and socio-demographic factors, and gallstones removed at surgery were collected from patients with cholelithiasis admitted to Teaching Hospital, Peradeniya, Sri Lanka from May 2011 to December 2012. External and cross sectional morphological features of gallstones were recorded by naked eye observation. Compositional analysis was carried out by Fourier Transform Infrared Spectroscopy, X - ray Powder Diffraction, and Atomic Absorption Spectrophotometry. Scanning Electron Microscopy was used to identify the microstructure of gallstones. RESULTS: Data of 102 patients were analyzed. Of them majority (n = 77, 76%) were females with a female: male ratio of 3:1. Mean age of the study group was 46.1±11.6 years. All the patients had primary gallbladder stones. According to the physical and chemical analysis, majority (n = 54, 53%) were pigment gallstones followed by mixed cholesterol gallstones (n = 38, 37%). Only 10 (9%) had pure cholesterol gallstones. Calcium bilirubinate, calcium carbonate and calcium phosphate were the commonest calcium salts identified in pigment gallstones and core of mixed cholesterol gallstones. CONCLUSION: Presence of a pigment nidus in gallstones is a common feature in majority of Sri Lankan patients denoting the possible role of elevated unconjugated bilirubin in bile on the pathogenesis of GS. Hence it is imperative to explore this further to understand the aetiopathogenesis of GS among Sri Lankans.

Serum lipid concentrations in patients with cholesterol and pigment gallstones.

BACKGROUND: Gallstones (GS) are formed as a result of impaired metabolic regulation of the human body. Abnormal lipid metabolism is partly responsible for the pathogenesis of GS mainly rich in cholesterol. Thus abnormalities of serum lipids would reflect the possibilities of the formation of cholesterol GS. This study aims to identify the significance of serum lipids on the development of GS disease. METHODS: Serum lipid profiles were estimated in 73 patients with symptomatic GS, admitted to the Teaching Hospital, Peradeniya, Sri Lanka for GS removal surgeries from May 2011 to December 2012. Patients with normal serum bilirubin level and not being on lipid lowering drugs were recruited for the study. Serum lipid profile of each patient was analyzed by enzymatic kit assays and the chemical composition of GS was analyzed by Fourier Transform Infrared spectroscopy. RESULTS: Of the 73 patients, 37 (51%) had cholesterol GS while 36 (49%) had pigment GS. Serum lipid parameters of a majority of patients were within the normal range. Body mass index values of the patients with two types of GS were not significantly different (Two sample t test, p = 0.335). Out of the lipid parameters tested, only serum triglyceride concentration was significantly high in patients with cholesterol GS than that of pigment GS (Two sample t test, p = 0.038). None of the lipid parameters were significantly different between males and females (Two sample t test, p > 0.05). Compared to the patients with pigment GS who were aged below 50 years, mean total cholesterol and triglyceride concentrations were higher in the same age category patients with cholesterol GS. CONCLUSION: Abnormal serum lipid profiles doesn't seem to be an essential feature in patients with cholesterol GS. However when the two groups of patients with cholesterol and pigment GS with no significant difference of body mass indexes were compared, patients with cholesterol GS are more likely to have serum lipid parameters towards the undesirable cutoff levels of their respective normal ranges. However an effect of serum lipid concentrations on high incidence of GS among females has not been identified.

Can the type of gallstones be predicted with known possible risk factors?: A comparison between mixed cholesterol and black pigment stones.

BACKGROUND: Pathogenesis of gallstones (GS) is multifactorial and multiple genetic and environmental factors have been identified in different populations for different types of GS with varying prevalence. However the role of the each aetiological factor on the formation of mixed cholesterol and black pigment GS has not being addressed adequately. Hence in this study we attempted to compare known possible risk factors for mixed cholesterol and black pigment GS among two groups of patients with two types of GS. METHODS: The study was done on a cohort of patients with symptomatic GS admitted to the Teaching Hospital Peradeniya, Sri Lanka over a period of 18 months. Clinical and epidemiological data and physical parameters of the patients were recorded and surgically removed GS were analyzed chemically and physically to identify the type of GS. In addition lipid profile was done in all the patients with normal serum bilirubin levels. RESULTS: A total of 86 patients were included in the study. Mixed cholesterol GS was significantly common among females than males (χ2 test, p = 0.029). Mixed cholesterol GS was commonly seen among patients belonging to Moor ethnicity (χ2 test, p = 0.009). Majority of patients with mixed cholesterol GS had body mass index above 25 kg/m2 (χ2 test, p = 0.018). Black pigment GS were significantly common among patients with type II diabetes mellitus (Fisher's exact test, p = 0.035). Further all the patients with chronic haemolytic anaemia and alcoholic cirrhosis had black pigment GS. Age, family history, Fasting Blood Glucose, dyslipidaemia, lipid profile, parity and use of oral contraceptive pills in females, smoking and alcohol intake in males did not differ significantly among patients in the two groups. CONCLUSION: Gender, ethnicity and body mass index can be used to predict the formation of mixed cholesterol GS and black pigment GS.