Efficacy of Ochna integerrima (Lour.) Merr leaf extracts against seedling growth of six important plants

Abstract

Ochna integerrima (Lour.) Merr, a deciduous shrub in the family Ochnaceae, is a great source of active compounds and is used as a medicinal plant in tropical Asia, Africa, and America. Previous studies have focused on the pharmacological properties of O. integerrima; however, the allelopathic potential of this plant has not yet been identified. Therefore, this study was carried out with completely randomized design to determine the allelopathic potential of O. integerrima leaf extracts in six concentrations against the seedlings growth of dicots plants [garden cress (Lepidium sativum L.), lettuce (Lactuca sativa L.), and alfalfa (Medicago sativa L.)] and monocot plants [Italian ryegrass (Lolium multiflorum Lam.), timothy (Phleum pratense L.), and barnyard grass (Echinochloa crusgalli (L.) Beauv.)]. The results showed that the leaf extracts inhibited the seedling growth of all the test plants at concentrations ≥10 mg dry weight (D.W.) equivalent extract mL−1, except for the barnyard grass shoots. The concentrations needed for 50% inhibition (I50 values) of the shoot and root growth of the test plants were in the ranges 1.97–48.01 and 1.18–9.64 mg D.W. equivalent extract mL−1, respectively. The I50 values showed the roots of all the tested plants were more susceptible to the extracts than their shoots, except alfalfa. These findings suggested that the leaf extracts of O. integerrima may possess allelopathic substances which could be used as a source of bio-herbicide for reducing the weed burden in crop fields. Thus, more research is needed to isolate and identify the allelopathic substances in O. integerrima in order to produce bio-herbicide for weed management