Bioactive compounds from plants and their utility in lymphatic filariasis drug development

Lymphatic Filariasis is a tropical, mosquito-borne disease that is the second leading cause of disability world-wide. It is caused by filarial nematodes which cause inflammation and disability through damage to the lymphatic system. Currently 53 countries have adopted Mass Drug Administration (MDA) programs that deliver antifilarial drugs to at-risk populations annually until the parasite is cleared from the population. Outside of the capacity of the current drugs, however, is the ability to 1) directly affect the clinical outcome of the disease with respect to inflammation and 2) target stages of the parasite\u27s life cycle other than the infant stage. Inflammation in LF is primarily due to the release of antigenic material from the parasite when it is an adult and when it completes the L3/L4 molt. Bioactive plants such as Neurolaena lobata may hamper inflammation by killing the third larval stage of the parasite (L3), which would in turn prevent the formation of adults and the L3/L4 molt. Furthermore, bioactive plants may alleviate clinical symptoms and speed up eradication of the disease by promoting steady and compliant consumption of LF drugs through incorporation into the human diet. The utility of N. lobata leaves as a prophylactic for LF was tested by examining the effect of extracts of N. lobata on (1) mortality of the third larval stage (L3) of B. pahangi and (2) the ability to of the L3 larvae to complete the L3/L4 molt. N. lobata\u27s potential to be incorporated into the diet was assessed by testing its toxicity to the non-nematode species Artemia salina. We found the extract of N. lobata to cause statistically significant mortality of B. pahangi L3 larvae starting from 24 hours in an vitro culture system and resulting in 100% mortality by 84 hours. Additionally, L3s treated with N. lobata were not able to complete the L3/L4 molt and the toxicity of N. lobata to the filarial parasite was not repeated in non-nematode species Artemia salina