Aqueous, organic and alcoholic extracts of over 100 samples of 60 species of Kallawaya medicinal herbs representing 30 plant families were assayed to compare their toxicity and ability to protect MT-2 T-lymphoblastoid cells from the cytopathic effect of human immunodeficiency virus (HIV). The results are reported as a therapeutic index (TI) which was > 25 for eighteen species, including seven > 50 and one > 100. The anti-HIV activity resided primarily in the aqueous rather than in the organic extracts and was concentrated in plants used in ethnomedicine to treat lung and liver diseases.
PIP: Plants are a rich source of anti-viral substances. The National Cancer Institute therefore annually screens about 1500 species from Africa, Southeast Asia, and South and Central America, but not Bolivia, for anti-HIV activity. Several unique compounds with anti-HIV activity have emerged from the program. The Kallawaya Indians of Bolivia follow a medical tradition from the Tiahuanaco (400-1145), Mollo (1145-1435), Inca (1438-1532), Spanish (1532-1825), and Bolivian Republic (from 1825) which is only recently starting to be reported. They use approximately 900 of the more than 2000 medicinal plants found across Bolivia. Aqueous, organic, and alcoholic extracts of more than 100 samples of 60 species of Kallawaya medicinal herbs representing 30 plant families were assayed to compare their toxicity and ability to protect MT-2 T-lymphoblastoid cells from the cytopathic effects of HIV. The therapeutic index (TI) of sampled species is defined as the ratio of anti-HIV activity to toxic concentration. A TI of greater than 25 was chosen as the prerequisite for future bioassay-directed isolation of the active components as leads for potential new anti-HIV drugs. TI was greater than 25 for 18 species, including seven greater than 50 and one greater than 100. The anti-HIV activity resided mainly in the aqueous extracts and was concentrated in plants used in ethnomedicine to treat lung and liver diseases.