Dendrophthoe falcata (L.f.) Ettingsh is a hemiparasitic plant, used in Sri Lankan and Indian indigenous medicine to treat various diseases such as asthma, cancerous tumors, diabetes and wounds. Despite the hemiparasite on the host Limonia acidissima is used to treat various diseases, any bioactivity study of Dendrophthoe falcata grown on the particular host has not been conducted yet. This study aimed to investigate several bioactivities of the hemiparasite grown on Limonia acidissima (La) and compare with that grown on Mangifera indica (Mi). Sequential extracts by Soxhlet method from hexane (La-HE and Mi-HE), ethyl acetate (La-EAE and Mi-EAE) and methanol (La-ME and Mi-ME) were investigated for bioactivities. Antioxidant activity was determined using DPPH radical scavenging assay in which Mi-ME and Mi-EAE showed the highest activity, that is five times more than that of α-tocopherol. Brine shrimp lethality assay was conducted as a preliminary toxicity assay, where La-EAE showed the highest activity that is approximately four times that of K 2 Cr 2 O 7 . The total polyphenolic content was determined by Folin-Ciocalteu method in which both methanol extracts showed the highest polyphenolic content of which Mi-ME was approximately four times more than that of La-ME. These results suggest that the bioactivity of the hemiparasite vary considerably with the host. Further, extracts of the hemiparasite on Limonia acidissima showing high antioxidant activity coupled with high toxicity justifies its applicability in indigenous medicine.

Dendrophthoe falcata (L.f.) Ettingsh (Loranthaceae family) is a hemiparasite which has many medicinal applications and grows on a variety of hosts. Bioactivity of the hemiparasite shows a great host dependence, where it contains high antioxidant activity coupled with high toxicity when grown on the host Limonia acidissima. This study aimed to investigate the impact of environmental conditions on the bioactivity of the hemiparasite grown on L. acidissima (Rutaceae family), as the environmental stress may play a determining role in the production of secondary metabolites in a plant. The hemiparasite grown in Hambantota (Hamb -dry zone), Kurunegala (Kuru -intermediate zone) and Ambalantota (Amba -dry zone), were selected for this study. Sequential extracts by Soxhlet method from hexane (HE), ethyl acetate (EAE) and methanol (ME) were compared for antioxidant activity, polyphenolic content, toxicity and alkaloid content determined by DPPH, Folin-Ciocalteu, brine shrimp lethality and acid-base assays respectively. Antioxidant activity was approximately 40% higher for Kuru-ME compared to Hamb-ME and Amba-ME. A significant 180 -200% higher polyphenolic content was observed for Hamb-ME compared to the Amba-ME and Kuru-ME. Toxicity studies revealed that Hamb-EAE is 43% and 29% more toxic than Kuru-EAE and Amba-EAE. The alkaloid content of Hamb-ME showed the highest percentage with a less significant difference between the extracts of other two locations. On average, among the three locations, extracts of Kurunegala, Ambalantota and Hambantota showed the least, intermediate and highest bioactivities respectively experiencing the least, intermediate and most environmental stressed conditions. Hence, it can be concluded that the bioactivity is influenced by the environmental stress due to the impact of governing the secondary metabolites produced by Dendrophthoe falcata.