Phytochemical Screening and Nematicidal Activity of Cinnamon and Ginger Extracts Against Root-knot Nematode (Meloidogyne incognita) Infecting Tomato

Abstract

The purpose of this work was to assess the nematicidal and antioxidantactivities of different extracting solvents from cinnamon (Cinnamomum zeylanicum)and ginger (Zingiber officinale) against Meloidogyne incognita infecting tomato.Three solvents namely n-hexane, ethyl acetate and methanol were used.Phytochemical analysis of such extracts revealed the presence of morecomponents in ethyl acetate and methanolic extracts than n-hexane extract of eithercinnamon or ginger. The highest amount of total phenolics and flavonoids weredetected in ethyl acetate extract of both ginger and cinnamon reaching 105.6; 93.6mg gallic acid /g and 54.2; 45.1 mg quercetin/ g dry weight, respectively.Additionally, ethyl acetate and methanolic extracts of ginger exhibited the highestantioxidant activity (DPPH free radicals) reaching 90.0 and 89.1%, respectively. Theefficacy of cinnamon and ginger using three solvents at two concentrations (50 and10ul) on juveniles mortality of Meloidogyne incognita was studied in vitro. Ethylacetate extracts gave better results than did methanol or hexane extracts. Gingerextracts gave promising results after 72hr of exposure compared to cinnamon ones.Hence, among ginger extracts the maximum mortality in nematode juveniles wasachieved with ethyl acetate (68.0 %) followed by methanol (42.0%) and hexaneextracts (30%) @ the concentration of 50μl after 72 hours of exposure. Ginger ethylacetate (300 ppm) proved to be the best for enhancing total plant fresh weight withpercentage of increase over control amounted to 196.0 %. Population densities,root galling and number of egg masses were significantly suppressed with suchtested extracts. Leaves of tomato were assayed for NPK, total cholorophyll,proteins, and phenols. Activities of polyphenol oxidase (PPO), peroxide oxidase(PO) were also evaluated in roots of tomato infected with M. incognita. PO activitywas much greater in ginger ethyl acetate at lower concentration (100 ppm).Conversely, PPO activity was increased in cinnamon ethyl acetate (100 ppm).Thepresent study revealed high potential antioxidants and nematicidal properties inboth cinnamon and ginger. The biological activities of these plants might beattributed to the various kind of secondary metabolites.