In vitro nematocidal effects of medicinal plants from Sao Paulo state, Brazil

Synthetic nematicides have been used broadly in past decades for the control of plant parasitic nematodes. Despite their relevant effectiveness, these compounds can cause great damage to the environment, and have a relevant impact on human and animal health. The growing search for new nematicides, particularly natural ones, may lead to higher safety and efficiency in nematode control. In this work, the in vitro nematocidal effect of ethanol extracts obtained from the following plant species was evaluated: Tithonia diversifolia (Hemsl.) A.Gray; Ecilpta alba (L.) Hassk; Mikania glomerata Sprengel (Asteraceae); Tabernaemontana catharinensis A. DC; Mandevilla velutina (Mart.) Woodson (Apocynaceae); Casearia sylvestris Sw. (Salicaceae); Zeyheria montana Mart. (Bignoniaceae); Lippia alba (Mill.) (Verbenaceae); Croton antisyphiliticus Mart. (Euphorbiaceae) and Serjania erecta Radlk. (Sapindaceae). The plant parasitic nematodes Pratylenchus zeae (Graham) (Nematoda: Pratylenchidae) and Pratylenchus jaehni (Inserra) (Nematoda: Pratylenchidae) were used for tests. Moreover, a preliminary phytochemical characterization of these plant extracts was performed in order to associate these data with those observed in nematocidal assays. Our results indicated a significant nematocidal activity of the analyzed extracts, especially those demonstrated by E alba (DL50 (ppm) = 304.08; 55.32 - P. zeae and DL50 (ppm) =>1000; 212.82 - P.jaehni; 12 and 24h, respectively), T catharinensis (DL50 (ppm) = 215.26; 60.04 - P. zeae and DL50 (ppm) = 825.44; 376.60 - P. jaehni; 12 and 24h, respectively), C. sylvestris (DL50 (ppm) = 198.05; 56.94 - P. zeae and DL50 (ppm) = 747.98;322.98 - P. jaehni; 12 and 24h, respectively), Z. montana (DL50 (ppm) = 166.43;34.08 - P. zeae and DL50 (ppm) =>1000;427.34- P. jaehni; 12 and 24h, respectively) and S. erecta (DL50 (ppm) = 178.74; 74.12 - P zeae e DL50 (ppm) = 689.24; 249.50 - P. jaehni; 12 and 24h, respectively). Thus, these data show that the evaluated plants present significant nematocidal effects, which are of high economic or environmental interest and may be useful for the growth of agricultural activities worldwide.