Aralia armata roots: Extraction, isolation and molluscicidal activity against golden apple snails, Pomacea canaliculata

Aralia armata is one of the common herb species in mountainous areas, especially in the northern mountainous areas of Vietnam, which has potential in pharmaceutical and agricultural industries. Herein, we report that an oleanolic acid saponin named pseudogisenoside RT1 methyl ester (A) was isolated from the roots of the species Aralia armata. The fractionated extracts of dichloromethane, ethyl acetate, water and compound A were investigated for their molluscicidal effects, specifically on Pomacea canaliculata. The tests showed that the extracts and compound A from A. armata roots had good activity against P. canaliculata snail. In particular, compound A had a Lethal concentration of 50 (LC50) value of 16.443 µg/mL.

Evaluation of the molluscicidal activities of arylpyrrole on Oncomelania hupensis, the intermediate host of Schistosoma japonicum

The snail Oncomelania hupensis is the only intermediate host of the highly invasive parasite Schistosoma japonicum. Molluscicide is often used to curb transmission of S. japonicum. Niclosamide, the only World Health Organization (WHO) recognized molluscicide, presents major drawbacks, including high cost and toxicity towards aquatic animals. In the present study, a number of aryl pyrrole derivatives (ADs) were synthesized to serve as potential molluscicides and were tested on O. hupensis. To uncover the underlying mechanisms, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were assessed in the soft body of ADs-exposed O. hupensis, using high performance liquid chromatography (HPLC). The effect of C6 on key points of energy metabolism (the activities of complexes I, III, IV and the membrane potential) was determined. We demonstrated that the Compound 6 (C6, 4-bromo-1-(bromomethyl)-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile) exerted the strongest molluscicidal activity against adult O. hupensis at LC50 of 0.27, 0.19, and 0.13 mg/L for 24, 48, and 72 h respectively. Moreover, we found that the bromide on the pyrrole ring of C6 was essential for molluscicidal activity. Furthermore, the ATP content reduced from 194.46 to 139.75 μg/g after exposure to 1/2 LC50, and reduced to 93.06 μg/g after exposure to LC50. ADP, on the other hand, remained the same level before and after C6 exposure. We found that C6, at 1/2 LC50, reduced the membrane potential of O. hupensis, while no significant changes were observed in the activities of complexes I, III, and IV. C6 was identified with excellent activities on O. hupensis. The obtained structure−activity relationship and action mechanism study results should be useful for further compound design and development.

Applicability of Euphorbia milii var splendens latex in the control of Biomphalaria tenagophila

The present work aimed to evaluate in vitro the molluscicidal activity and latex toxicity of Euphorbia milii var. splendens (Bojer ex Hook) Ursch & Leandri for the control of mollusks of the species Biomphalaria tenagophila. Specimens of E. milii var. splendens cultivated in the rural region of Pindamonhangaba were selected, from which latex was obtained by the transverse incision of the aerial parts. For the molluscicide test, adult mollusks of the species B. tenagophila were separated into groups of 10 and submitted to latex immersion at concentrations of 2.5 ppm, 1.25 ppm, 0.625 ppm, and 0.3125 ppm for 24 hours. In parallel, the toxicity of latex at a concentration of 0.3125 ppm was determined by testing with Artemia salina (mortality assessment) and using the Allium cepa test (determination of growth inhibition, amount, and weight of roots). It was observed an important molluscicidal activity of E. milii var. splendens latex at the various concentrations evaluated. In addition, it was also possible to observe moderate toxicity against A. salina nauplii and in the toxicity test with A. cepa. This demonstrates the potential of using latex from E. milii var. splendens to control populations of B. tenagophila species, not only for the observed molluscicidal activity but also for the moderate mortality of A. salina nauplii, whereas in the A. cepa test no change was observed in the parameters evaluated in relation to the control group, demonstrating safety for use in the environment.

MOLLUSCICIDAL ACTIVITY OF ZINGIBER OFFICINALE AND CARICA PAPAYA ON THE EGG HATCHABILITY OF THE GOLDEN APPLE SNAIL, POMACEA CANALICULATA (GASTROPODA: AMPULIRIIDAE)

The study was conducted to assess the effect of Zingiber officinale and Carica papaya extract on the egg hatchability of the golden apple snail, Pomacea canaliculata. This is a freshwater snail that is considered a pest in agriculture as well as natural ecosystems. In combating the population of the aforementioned pest, this study evaluates the use of plant extracts such as biomolluscicides to control the production of new hatchlings from the clusters of eggs. The egg clusters were exposed to different concentrations of Z. officinale ethanolic extract and C. papaya methanolic extracts (25 ppm, 50 ppm, 100 ppm) using the direct single spraying method. Observation was made for a maximum of 30 days. The time taken for the eggs to hatch and the number of eggs successfully hatched were measured to reflect the potential of both extracts in affecting egg hatchability. The finding shows that the eggs hatch later when exposed to increasing concentrations (25 to 100 ppm) of Z. officinale extract. The number of eggs successfully hatched was significantly decreased from 86% to 9% after exposure to 25 ppm and above. Meanwhile, the extract of C. papaya did not show any significant effect on both parameters for egg hatchability of P. canaliculata, regardless of the increase in concentration from 25 to 100 ppm. Our findings reveal that the extract of Z. officinale contains higher molluscicidal activity than the extract of C. papaya. Therefore, it has the potential to be commercialized as a biomolluscicide to control the population of golden apple snails specifically at the egg stage.

Molluscicidal activity of Ipomoea batatas leaf extracts against Pomacea canaliculata (Golden apple snail)

This study was conducted to investigate the molluscicidal activity of four different Ipomoea batatas (I. batatas) leaf extracts (hexane, chloroform, methanol, and aqueous extracts) against Pomacea canaliculata (P. canaliculata) and screen the phytochemical compounds of I. batatas leaf extracts. The golden apple snails (size range: 20–40 mm) were exposed to three concentrations (1000, 5000, and 10,000 ppm) of each extract (hexane, chloroform, methanol, and aqueous extracts). The efficacy of the I. batatas extracts was laboratory-tested by submerging the P. canaliculata into paddy-filled water mixed with the extracts and the mortality was observed every 24 hrs for 3 days. The presence of phytochemical compounds such as terpenoids, flavonoids, saponins, tannins, alkaloids, and glycosides were tested. For all extracts, the results showed a positive relationship between the concentration and the golden apple snail mortality, suggesting that all extracts have molluscicidal properties. The study showed more than 50% mortality rate of P. canaliculata after 72 hrs for each treatment. Chloroform and methanol I. batatas leaf extracts at 10,000 ppm showed 100% mortality after 72 hrs due to the presence of saponin. Saponin causes the death of the snails by disturbing their feeding and growth and blocking their breathing process. For further research, it is suggested to conduct the study under field trials in the search for a natural and environment-friendly molluscicide.

Essential oils of the leaves of Syzygium cumini (L.) Skeels and fruit peels of Hymenaea courbaril (L.) var. courbaril as molluscides against Biomphalaria glabrata

This study evaluated the molluscicidal activity of essential oils (EOs) of Syzygium cumini L. and Hymenaea courbaril L. Hydrodistillation was used to extract the EOs. The chemical characterization was performed by Gas Chromatography coupled to mass spectrometry. The bioassay of Artemia salina Leach was used for the toxicity test. The molluscicidal assay tested concentrations of 10-80 mg L-1 of the EOs against Biomphalaria glabrata. The major constituent of The EO of S. cumini was isokaryophyllene and H. courbaril the Germacreno-D. The toxicity assay classified The EOs as nontoxic with LC50 412.10 mg L-1 for S. cumini and LC50 354.80 mg L-1 for H. courbaril. The molluscicidal assay purchased LC50 44.76/ LC90 77.20 for S. cumini and LC50 37.34 mg L-1/ LC90 73.24 mg L-1 for H. courbaril. The results showed that both EOs can be used as natural molluscicides in combating the snail Biomphalaria glabrata.