Peripheral neuropathy induced by drinking water contaminated with low-dose arsenic in Myanmar

BACKGROUND@#More than 140 million people drink arsenic-contaminated groundwater. It is unknown how much arsenic exposure is necessary to cause neurological impairment. Here, we evaluate the relationship between neurological impairments and the arsenic concentration in drinking water (ACDW).@*PARTICIPANTS AND METHODS@#A cross-sectional study design was employed. We performed medical examinations of 1867 residents in seven villages in the Thabaung township in Myanmar. Medical examinations consisted of interviews regarding subjective neurological symptoms and objective neurological examinations of sensory disturbances. For subjective neurological symptoms, we ascertained the presence or absence of defects in smell, vision, taste, and hearing; the feeling of weakness; and chronic numbness or pain. For objective sensory disturbances, we examined defects in pain sensation, vibration sensation, and two-point discrimination. We analyzed the relationship between the subjective symptoms, objective sensory disturbances, and ACDW.@*RESULTS@#Residents with ACDW ≥ 10 parts per billion (ppb) had experienced a "feeling of weakness" and "chronic numbness or pain" significantly more often than those with ACDW  50 ppb). These data suggest a threshold for the occurrence of peripheral neuropathy due to arsenic exposure, and indicate that the arsenic concentration in drinking water should be less than 10 ppb to ensure human health.

Determination of phytochemical constituents and antioxidant activity of Rasayana, Triphala and antiageing herbal plants.

Antioxidants possess the ability to protect the body from damage caused by free radical induced oxidative stress and have antiageing property. ‘Theinga Dara Thanhitar’ book, written by Ashin Nagathein described that ‘Rasayana and Triphala’ drugs have the ability to prevent ageing and illness. This study was carried out to investigate the antioxidant activities of commonly used ingredients of ‘Rasayana’ such as Streblus asper Lour. (Okhne), Cassia fistula Linn. (Ngu), Tinospora cordifolia Miers. (Sindone-Ma-Nwe), Asparagus racemosus Willd. (Shin-Matet), Boerhavia diffusa Linn. (Payan-Nawa), and ‘Triphala’ such as Phyllanthus emblica Linn. (Ze-Phyu), Terminalia chebula Retz. (Phan-Ga) and Terminalia belerica Roxb. (Thit-Saint). Their absorbances were evaluated using 1,1-diphenyl -2-picrylhydrazyl (DPPH) assay method by using spectrophotometer. Yield percents of these plants were ranging from 4.05% to 28.6%. The watery extracts of Okhne, Ngu, stem of Sindone-Ma-Nwe, tubor of Payan-Nawa, Ze-Phyu, Phan-Ga, and Thit-Saint contain phenols and tannins which have free radical scavenging activities. It was found that the bark and stem of Okhne, tubor of Payan-Nawa and ‘Triphala’ had the least IC50 value i.e. the best antioxidant potency. Therefore, the findings from this study supported the experience-based findings of antiageing activities in ‘Triphala’ and ‘Rasayana’ to be evidence-based.