The AcOEt extract used at a concentration of 100 µg / mL demonstrated behavioral alterations among larvae, with low mobility and lethargy within 24 hours of larval treatment (L 3). Concerning the mosquito development cycle, the larval period was reduced by four days (7 ± 1.2 days; P <0.0001) at a concentration of 100 µg / mL when compared with the testimony control group (11 ± 2 days). In turn, the L 3 - adult period was reduced by three days (10 ± 1.8 days; P <0.001) (as shown in Table 1 (1 A )) compared with the testimony control group (13 ± 1.9 days). The same extract presented 96.7 % (P <0.001) and 86.7 % (P <0.001) larval mortality (L 3) at concentrations of 200 µg / mL and 100 µg / mL, respectively, for up to 48 hours of treatment (as shown in Table 1 (1 B )). This extract revealed an LC 50 value of 37.2 µg / mL. In addition, bioassays with the AcOEt extract demonstrated larval viability (L 3 - L 4) of only 3.3 % (200 µg / mL) and 13.3 % (100 µg / mL). At lower concentrations, the AcOEt extract at 50 µg / mL reduced the larval period by four days (8.1 ± 1.7 days; P <0.0001) as compared with the control testimony (12.5 ± 3.1 days) (as shown in Table 2 (2 A )). The time required for L 3 - to-adult development showed a reduction at concentrations of 10 µg / mL (12.9 ± 2.8 days; P <0.1) and 50 µg / mL (10.8 ± 1.9 days; P <0.0001), in relation to the control testimony (15.3 ± 3.3 days) (as shown in Table 2 (2 A )). The same extract showed low mortality among L 3 larvae at concentrations of 1 µg / mL and 10 µg / mL (6.7 % and 10 %), respectively (as shown inTable 2 (2 B )). Similarly, mortality was low in the case of L 4 larvae (10 and 5 %) (as shown in Table 2 (2 B )). At the concentration of 50 µg / mL, the extract presented moderate mortality for L 3 (40 %) (P <0.01), but low mortality for L 4 and pupae (13.3 % and 3.5 %), respectively (as shown in Table 2 (2 B )). Regarding the larval development period, the MeOH extract at concentration of 200 µg / mL (8.5 ± 0.9 days; P <0.0001) reduced the larval period, in comparison with the testimony control (11.8 ± 1.9 days). Besides, the pupal period at concentrations of 100 µg / mL (2.1 ± 0.4 days; P <0.01) and 200 µg / mL (4.5 ± 2.2 days; P <0.0001) were extended when compared with the testimony control group (1.7 ± 0.6 days) (as shown in Table 3 (3 A )). Twenty-four hours after treatment, the larvicidal activity of the MeOH extract of M. charantia resulted in low mobility and lethargy among the larvae. Mortality of L 3 larvae reached 70 % (P <0.001) at the concentration of 200 µg / mL (as shown in Table 3 (3 B )), with 20 % viability (P <0.01) for L 3 - adult development, resulting from larval disintegration and thus reducing the chances of larval emergence. This extract exhibited low toxicity at the concentration of 100 µg / mL, with only 1.7 % L 3 larval mortality, 10 % L 4 larval mortality, and 3.3 % pupal mortality (as shown in Table 3 (3 B )). Furthermore, the MeOH extract presented LC 50 = 129.6 µg / mL. The results indicated that the HEX crude extract showed low larval toxicity at a concentration of 100 µg / mL and resulted in 78 - 90 % larval emergence. Considering the development period, these results were statistically similar to those obtained from the testimony control group.
Sumber: Momordica charantia L. extracts against Aedes aegypti larvae