Phytotoxicity Study on Bidens sulphurea Sch. Bip. as a Preliminary Approach for Weed Control.

Farmers of the Franca region in Brazil observed that Bidens sulphurea was able to eliminate the Panicum maximum weed, which infected coffee plantations, without affecting the crop. In an effort to determine if the inhibitory effects observed were due to the presence of phytotoxic compounds from leaves and roots, a biodirected isolation and spectroscopic characterization has been carried out. The leaf dichloromethane and root acetone extracts were the most active, and the former appeared to be more phytotoxic to the target species, including four weeds. A total of 26 compounds were isolated from leaves and roots, and four of them are described here for the first time. The major compounds in the leaf extract are the sesquiterpene lactones costunolide, reynosin, and santamarine, and these showed marked inhibition. Amaranthus viridis and Panicum maximum were the most sensitive species of the weeds tested. These three phytotoxic lactones were also evaluated on A. viridis and P. maximum under hydroponic conditions. A. viridis was the most affected species with the three lactones, and santamarine was the most phytotoxic compound on both. This is the first time that the phytotoxicity of sesquiterpene lactones has been evaluated on hydroponic culture. The work described here is a preliminary approach for the use of B. sulphurea for weed control in agriculture, both as a cover crop and by use of its components as natural herbicide leads.

Celiac disease in first-degree relatives of patients.

OBJECTIVE: To determine the prevalence of celiac disease and to describe the histological alterations, clinical manifestations, and conditions associated with a group of first-degree relatives of celiac disease patients in the municipality of Recife, Northeast Brazil. METHOD: The study was conducted in outpatient clinics of pediatric gastroenterology located in Recife. We included in the study 174 first-degree relatives who were screened for the anti-transglutaminase IgA antibody. Those relatives who had positive serological tests were invited to undergo a small intestine biopsy (classified according to Marsh). They were also evaluated regarding weight, height, clinical symptoms and conditions associated with celiac disease. The chi-square test and Fisher's exact test were used to assess the differences with a significance level of p < 0.05. RESULTS: The anti-transglutaminase IgA antibody was positive for 20.1% (34/174) of the relatives (95%CI 14.6-26.5). There was no difference in terms of positive serological tests regarding either degree of kinship or sex. Twenty-two patients underwent biopsy. Thirteen had histological alterations classified as Marsh stage 3; seven had stage 1; and two had stage zero, with a probable prevalence of 11.5%. All patients, except for one, had symptoms; the only patient with no symptoms was short. CONCLUSION: Celiac disease prevalence in this group of relatives was high. All new cases identified were symptomatic or had associated conditions. In this group, there was a high frequency of individuals with positive serological tests, symptoms suggestive of celiac disease, and no evidence of villous atrophy in the intestinal mucosa.