#bioassay

This study aimed to evaluate the presence of bioactive compounds in Homalocladium platycladum (Tapeworm plant) through bioactivity screening and toxicity assessment. The powdered mature stems of the plant were extracted using different solvents, namely n-hexane (HEX), dichloromethane (DCM), ethyl acetate (ETA), n-butanol (BUT), and methanol-water (WAT). The resulting fractions were prepared and tested at various concentrations using the brine shrimp lethality assay. The results indicated that the HEX, DCM, and BUT fractions exhibited immediate and acute toxicity, suggesting the presence of bioactive compounds. Furthermore, all fractions demonstrated toxicity at longer exposure times, indicating the potential for chronic toxicity. The median lethal concentration (LC50) analysis using the Miller-Tainter method revealed moderate toxicity for the HEX and DCM fractions, with LC50 values of 199.9 ppm and 457.3 ppm, respectively. Moreover, all fractions, including HEX, DCM, ETA, BUT, and WAT, exhibited bioactivity potential at longer exposure times, with calculated LC50 values of 19.79 ppm, 38.82 ppm, 14.77 ppm, 5.565 ppm, and 131.3 ppm, respectively. Notably, all fractions, except for the methanol-water fraction, displayed high toxicity after 24-hour exposure. These findings suggest that the Tapeworm plant contains bioactive compounds with pharmacological potential. Therefore, further investigation of these compounds is warranted for the development of novel pharmaceutical agents.

The different biorational pesticides were evaluated against R. solanacearum (Smith) both in vitro and in vivo conditions. In the in vitro assay using spread plate method, fermented vegetables applied at the rate of 1ml/L of water showed a high degree of efficacy against the bacterial pathogen at one, two, and three days after incubation (DAI) with average inhibitory zones of 2.15 mm, 1.74 mm, and 1.44 mm, respectively. Under in vivo conditions, the inoculated tobacco plants manifested symptoms typical of bacterial wilt due to R. solanacearum (Smith). However, a comparable percent wilt incidence was noted on plants applied with fermented vegetables and other biorational pesticides. Moreover, the growth parameters of tobacco such as plant height, leaf length, fresh leaf weight, and the total number of harvested leaves per plant were not affected by the application of biorational pesticides. The results indicate that fermented vegetables are effective against R. solanacearum (Smith) under in vitro conditions, but did not show significant difference with the other treatments under in vivo conditions.