Allelopathic and antiproliferative potential of leaf aqueous extracts of Psidium cattleianum Sabine on Lactuca sativa L.

Abstract

Psidium cattleianum, also known as strawberry guava, is a Brazilian native species valued for its use in folk medicine.
We aimed to evaluate the allelopathic activity of P. cattleianum leaf aqueous extracts on Lactuca sativa (lettuce) seeds,
as well as the genotoxic and antiproliferative potential of extracts on cell division in lettuce roots, and test for the ability of
extracts to revert mutations resulting from glyphosate exposure. Leaves of two accessions were collected in Tupanciretã (TU)
and Silveira Martins (SiM). Bioassays were carried out in a germinator for 72 h at 25 ºC. Lettuce seeds were distributed in Petri
dishes containing three sheets of filter paper moistened with 6 mL of each of the following treatments: aqueous extracts prepared
by decoction of leaves at two concentrations (15 and 75 g.L-1), distilled water (negative control), and 2% glyphosate solution (positive control). We analyzed 4000 lettuce root cells from each treatment and calculated the respective mitotic indexes (MI). Statistical analysis was conducted using Chi-square and Scott-Knott tests (p < 0.05). The results showed that extracts of TU accession significantly decreased germination at both concentrations and inhibited cell division in L. sativa roots at concentration
75 g.L-1. The post-treatments significantly reversed the negative effect of glyphosate on seed germination. The mitotic index was also significantly reversed by aqueous extracts, yet more strongly by extracts of SiM accession. We concluded that the aqueous extracts of strawberry guava have an inhibitory allelopathic effect on seed germination in L. sativa, antiproliferative potential at concentration 75 g.L-1, and genotoxic properties.