antibacterial activity of the aerial extracts from xanthium brasilicum prepared in methanol, diethyl ether, petroleum benzene and an equal mixture of the three solvents were studied against bacterial laboratory standards and clinical isolates using the disk diffusion method. the best antibacterial results were obtained when methanol or the solvent mixture was used. the crude extract with the hi...

Vegetative plants of Xanthium strumarium L. grown in long days were induced to flower by exposure to one or several 16-hour dark periods. The distribution of male and female inflorescences on the flowering shoot was described, and a scoring system was designed to assess the development of the female inflorescences. The time of movement of the floral stimulus out of the induced leaf and the timi...

The leaves of the Xanthium spinosum plant have been used culturally in Paraguay for their medicinal properties. Acute toxicity of mature leaf extract was evaluated. For the study, 35 Balb/c mice were selected and allocated into 7 groups, 6 test groups and 1 control group. The extract was prepared in concentrations of 6% and 9% (g/dL). The 6% concentration was administrated to 3 test groups and ...

Four new glycosides, namely 3β-norpinan-2-one 3-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (1), (6Z)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-glucopyranoside (2), (6E)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-gluco-pyranoside (3), and 7-[(β-d-apiofuranosyl-(1→6)-β-d-glucopyranosyl)oxymethy]-8,8-dimethyl-4,8-dihydrobenzo[1,4]thiazine-3,5-dione (4), were isolated from the f...

Fluorescence and thermal imaging were used to examine the dynamics of stomatal patches for a single surface of Xanthium strumarium L. leaves following a decrease in ambient humidity. Patches were not observed in all experiments, and in many experiments the patches were shortlived. In some experiments, however, patches persisted for many hours and showed complex temporal and spatial patterns. Ra...

When a plant is rotated on a clinostat, with its axis parallel to the ground, the axis may remain straight. According to Sachs (9), the successive stimuli of gravity compensate each other and, therefore, there is no tropic reaction. Czapek (4) on the other hand, felt that under these conditions, there is no perception of the gravity by the plant and consequently no tropic reaction. In connectio...

Leaf resistance for water vapor (total diffusion resistance minus boundary layer resistance), transpiration, and leaf temperature were measured in attached leaves of greenhouse-grown Xanthium strumarium L. plants that had been pretreated for 72 hours with high (40 C day, 35 C night), or low (10 C day, 5 C night) air temperatures. Measurements were made in a wind tunnel at light intensity of 1.1...

The extraction procedures which have been successfully employed in the preparation of a florigenic principle from the tissues of Xanthium, are applicable to the derivation of an entity of similar activity from Calonectria culture. The Xanthium principle is acedic, with pK(a) values characteristic of a carboxylic acid (6). Although definitive chemical comparisons have not been completed, the ext...

The antiplasmodial active extract of Xanthium cavanillesii contains 3,4-dicaffeoyl quinic acid (3,4-DCQA), 3,5-dicaffeoyl quinic acid (3,5-DCQA) and 1,3,5-tricaffeoyl quinic acid (1,3,5-TCQA). These results inspired us to investigate the interaction of these molecules with a promising validated target of Plasmodium, PfATP6 orthologue of mammalian Ca+2-ATPase. Models of this receptor were obtain...