Study on the Synergistic Molluscicidal Effect of Pedunsaponin A and Niclosamide.

Niclosamide (NI) is the main molluscicide used to control Pomacea canaliculata (Lamarck) (Architaenioglossa: Ampullariidae). However, NI failed to inhibit snail climbing during the treatment process. In this study, we examined the effect of NI combined with pedunsaponin A at an ineffective concentration. The molluscicidal effect of Pedunsaponin A on NI was evidently synergistic after 48 h, and the synergism ratio (SR) was 1.82 after treatment for 72 h at 0.8 mg·L-1. Examination of the climbing adhesion effect showed that a high concentration of Pedunsaponin A (0.4 mg·L-1 and 0.8 mg·L-1) combined with NI significantly inhibited the climbing of P. canaliculata. We further studied the synergism mechanism; the results of histopathological observation showed that the siphon appeared cavities, the muscle fibers of the ventricular were severely dissolved, and kidney tubule arrangement was distorted after NI adding Pedunsaponin A. In addition, the hemocyte survival rate and the content of hemocyanin decreased significantly. According to the results of our study, the synergism mechanism may hinder oxygen transport of P. canaliculata, influencing the supply of energy; the ability of immune defense and excretion and metabolic detoxification decreased, prolonging the action time of NI in the body.

Compounds from the root of Pueraria peduncularis (Grah. ex Benth.) Benth. and their antimicrobial effects.

BACKGROUND: Pueraria peduncularis belongs to the genus Pueraria DC, and has a wide range of medical and agricultural activities. Previous studies have shown that P. peduncularis extracts have broad bioactivities against phytopathogens. In this paper, we systematically studied the fungicidal activity of root methanol extracts and further isolated the active compounds. RESULTS: The root methanol extract inhibited the mycelial growth of the five tested phytopathogens to different degrees. Among these phytopathogens, the inhibitory effect was greatest against R. solani, with an EC50 value of 324.72 mg L-1 . Eight compounds were subsequently isolated and identified from P. peduncularis. Among them, puercarpan A and medicarpin showed strong fungicidal activity, with MIC values against Rhizoctonia solani of 1.6 and 6.25 mg L-1 , respectively. Puercarpan A is a new compound, and its structure was established as (6aR,6bS,11aR)-6b-hydroxy-3-methoxypterocarpan-10-ene-7-one. CONCLUSION: The P. peduncularis extracts exhibit high antimicrobial activity against R. solani and have great potential value of P. peduncularis as a fungicide. © 2019 Society of Chemical Industry.