Evaluation of herbicidal and antimicrobial activity of essential oil of Vitex negundo L

Abstract

Weeds are the unwelcome plants that have high potential to colonize disturbed habitats as well as cultivable land. In agricultural fields, these interfere with the growth and development of crops and thus, reduce the quality and quantity of the agricultural produce and cause enormous losses to the farmers. The excessive use of synthetic herbicides in agriculture to control the weeds has steered the development of resistance in weeds along with the production of toxic effects on the environment. Owing to these problems, there is thus a great need to explore other alternates which are safer and also possess novel sites of action. Keeping this in mind, a study was therefore, planned to investigate the herbicidal and antimicrobial activity of essential oil extracted from Vitex negundo L. A dosedependent reduction in the percent germination, seedling growth, and chlorophyll content of the test plants were observed upon treatment with essential oil of V. negundo. However, the oil exhibited greater phytotoxicity towards weeds. (GC-MS) analysis of the oil reveal the presence of and#946; caryophyllene (27.80%) as major compound. Further, increase in the concentration of aqueous extract of powdered leaves and leaves powder amended in the soil reduced the percent germination, coleoptile and root length, and chlorophyll content of all the test plants. The (LC-MS) analysis of the leaf extract revealed the presence of about ten phenolic compounds in V. negundo leaf. Increase in oxidative stress in the treatment roots of S. occidentalis was reveals in terms of the increase in the generation of oxidative stress markers along with increase in the activities of antioxidant enzymes. Further, the treatment of oil also induced morphological and ultrastructural changes in roots of the S. occidentalis revealed through the TEM and SEM analysis. The oil showed cytotoxic effect in terms of increase in MI and chromosomal aberration percentage.