Bioherbicidal and cytogenotoxic potential of nanoemulsions containing essential oils from Piper amalago and Piper dilatatum.

Essential oils offer a viable alternative to traditional agrochemicals, mitigating problems such as environmental contamination and weed resistance. However, application faces challenges such as low solubility in water and rapid environmental degradation. To overcome these limitations, nanoemulsions containing essential oils from Piper amalago L. and Piper dilatatum Rich were formulated using ultrasonic homogenization. These nanoemulsions were investigated for their herbicidal properties through phytotoxic and cytogenotoxic activity assays using weed plants Bidens pilosa L. and Lolium multiflorum Lam., and model plant Lactuca sativa L. The results indicated that the nanoemulsions presented nanometric-sized droplets (~ 10 nm), PDI close to 0, and greater thermal stability compared to essential oils. The nanoemulsions exerted an inhibitory effect on germination and growth of plants studied, possibly due to cytogenotoxic and mutagenic damages observed. Furthermore, content of photosynthetic pigments was affected, indicating oxidative damage and changes in chlorophyll metabolism.