Goitrogenic content of Indian cyanogenic plant foods & their in vitro anti-thyroidal activity.

BACKGROUND & OBJECTIVES: Consumption of cyanogenic foods has been considered as one of the etiological factors in certain instances for the persistence of endemic goitre. The present study was undertaken to study the cyanogenic glucosides, glucosinolates and thiocyanate content in edible portion of certain selected plant foods of Indian origin. Further in vitro anti-thyroidal activity using raw, boiled and cooked extracts of these plants with and without excess iodide was also studied. METHODS: Cyanogenic plant foods generally vegetables were collected from different areas of West Bengal and Tripura. Cassava was obtained from Meghalaya and Kerala and their cyanogenic glucosides, glucosinolates and thiocyanate were estimated. Thyroid peroxidase activity (TPO) of human thyroid was assayed from microsomal fraction following I3- from iodide. The anti-TPO activities of the plants were assayed after adding raw, boiled and cooked extracts in the assay medium with and without extra iodide. Relative antithyroidal potency of the plant extracts was also evaluated in terms of the concentration (IC50) necessary to produce 50 per cent inhibition of TPO activity. PTU equivalence of the plant foods was also determined. RESULTS: Cabbage and cauliflower were rich in glucosinolates, bamboo shoot and cassava were rich in cyanogenic glucosides, mustard, turnip and radish were relatively rich in thiocyanate however all the constituents were present in each plant. Boiled extracts showed maximum inhibition of TPO activity followed by cooked and raw extracts. Excess iodide was found relatively effective for raw extract but less effective for boiled and cooked extracts in reversing anti-TPO activity. Inhibition constant (IC50) was found highest with bamboo shoot and least with cabbage. INTERPRETATION & CONCLUSION: Raw, boiled and cooked extracts of the plants showed anti-thyroidal activity in vitro. Excess iodide reversed the anti-TPO activity to same extent but could not neutralise it.

Iodine nutritional status of school children in a rural area of Howrah district in the Gangetic West Bengal.

The objective of the study was to assess the status of iodine nutrition in an area of Howrah district where iodine deficiency disorders (IDD) were reported despite the introduction of iodised salt for general use. A total of 969 school children in the age group 6-12 years of both sexes were clinically examined for goitre. On the spot 242 urine samples were collected from the children to study the iodine and thiocyanate excretion pattern and 108 edible salt samples were collected from the homes of the children to measure iodine level. Drinking water samples were collected to evaluate the bioavailability of iodine in the region. The total goitre prevalence was 37.6% (Grade 1: 32.6%; Grade 2: 4.9%). The median urinary iodine level was 35 microg/dL, 12.5% urine samples had iodine level below 10 microg/dL and no sample was found to contain iodine below 5 microg/dL. In 51.9% salt samples iodine level was below 15 ppm and the iodine level in the drinking water was about 82 microg/L. The people of the area consume foods from the vegetables of the Brassica family and mean thiocyanate level was 0.747+/-0.21 mg/dL. The-findings of the present study indicated that as per clinical criteria of WHO/UNICEF/ICCIDD, IDD is a severe public health problem though apparently there is no biochemical iodine deficiency. Overall results indicate that factors other than iodine deficiency may have a role in the persistence of endemic goitre in the post salt-iodisation in this region.