In vitro anti-rotavirus activity of some medicinal plants used in Brazil against diarrhea.

Acute diarrhea, especially in children, is a very common disease with worldwide distribution and with a significant public health impact. Rotaviruses have been recognized as the major agents of diarrhea in infants and young children in developed as well as developing countries. In Brazil, diarrhea is one of the principal causes of death, mainly in the infant population. To fight diarrhea, traditional Brazilian medicine uses a great variety of plants. In this work, 12 medicinal plant species were screened for simian (SA-11) and human (HCR3) rotaviruses inhibition in vitro. At non-cytotoxic concentrations, the extracts from Artocarpus integrifolia L. (Moraceae) bark (480 microg/ml) and Spondias lutea L. (Anacardiaceae) leaves (160 microg/ml) had antiviral activity against both viruses. They showed inhibition of 99.2% and 97%, respectively, for human rotavirus, and 96.4% and 96.2% for simian rotavirus. The extracts from Myristica fragrans Houtt (Myristicaceae) seeds (160 microg/ml) and Spongias lutea bark (40 microg/ml) inhibited human rotavirus (90% and 82.2% inhibition, respectively), whereas the extracts from Anacardium occidentale L. (Anacardiaceae) leaves (4 microg/ml) and Psidium guajava L. (Myrtaceae) leaves (8 microg/ml) showed activity only against simian rotavirus (82.2% and 93.8% inhibition, respectively). Our results indicate that the extracts of Artocarpus integrifolia, Myristica fragrans and Spongias lutea can be useful in the treatment of human diarrhea if the etiologic agent is a rotavirus.

A sulphated fucan from the Laminaria abyssalis inhibits the human T cell lymphotropic virus type 1-induced syncytium formation in HeLa cells.

This work evaluated the effect of a sulphated fucan extracted from the Laminaria abyssalis marine algae on the human T cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation. The experiments were carried out in HeLa cells cocultured with a HTLV-1-infected T cell line (C91/PL cells) in the presence of the sulphated polysaccharide at concentration below that corresponding to the ED50. The sulphated fucan inhibited almost 100% of the syncytium formation at concentration of 100 microg/mI and was still active (>95%) at a concentration of 25 microg/ml. It was also observed that the best inhibition occurred when the compound was added in the first 2 h of the cell-to-cell contact. This is the first report showing that a purified sulphated polysaccharide, extracted from marine algae, is able to inhibit the cell-to-cell contact essential for the spreading of the HTLV-1.

Anti-herpes simplex virus effect of a seed extract from the tropical plant Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae).

Incubation of acyclovir-resistant herpes simplex virus type 1 (ACVr-HSV1), during infection of the HEp-2 cell culture, with an extract prepared from the seeds of Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae) species impaired the productive replication of this virus in a concentration-dependent manner. The extract was able to inhibit extracellular virus (virucidal effect) and also interfered with a very early event of cell infection, at a non-cytotoxic concentration.