Fig. 1.

Screening of the plant extracts harboring JHAN and mosquito larvicidal activity. (A) JHAN activity of some plant extracts. The Met-CYC binding triggered by 33 ng/Ml pyriproxyfen was simulated by β-galactosidase activity in the yeast two-hybrid system. Inhibition of β-galactosidase activity by treatment with 10 ppm methoprene acid was used as a positive control. Each plant extract was added to the yeast culture at a concentration of 100 ppm. When multiple extracts from the same plant species were screened to have JHAN activity, only the extract with the strongest activity was selected for further screening (red column). For example, the trunks and leaves of L. erythrocarpa were excluded from screening (blue column) because the extract from the plant fruits had the strongest JHAN activity. (B) Distinction between JHAN and anti-yeast activity. Two plant extracts from Magnolia obovata trunks and Dioscorea septemloba roots (A, black column) were excluded from the screening because they significantly inhibited yeast growth compared with the control solvent. *P < 0.01 (Student t test), **P < 1.0E-5 (Student t test). (C) Correlation between JHAN activity and larvicidal toxicity in the screened plant extracts. ***P < 0.0001 (two-sample z-test).