Phytochemical Screening, Volatile Component Identification, and In Vitro Acaricidal Efficacy of Vernonia amygdalina Essential Oils

International Journal of Chemistry | Vol. 10, No. 1, January 2019 | pp. 1–8

DOI: 10.46882/2019/IJC/000123

Article Type: Original Research Paper

Title: Phytochemical Screening, Volatile Component Identification, and In Vitro Acaricidal Efficacy of Vernonia amygdalina Essential Oils

Names of Authors: S. A. Abdulrahman¹, L. E. G. O. Santos²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Minna, Nigeria.
²Department of Organic Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

Abstract: The widespread development of acaricide resistance among livestock ticks demands the isolation of alternative botanical formulations to minimize chemical toxicities in agrarian systems. This study describes the qualitative chemical characterization, essential oil isolation via Gas Chromatography-Mass Spectrometry (GC-MS), and in vitro acaricidal efficacy of Vernonia amygdalina (Bitter leaf) leaf extracts against Rhipicephalus microplus larvae. Essential oils obtained via hydro-distillation in a Clevenger apparatus were separated into 18 distinct peaks through GC-MS profiling, with beta-caryophyllene (38.4%), alpha-humulene (16.2%), and caryophyllene oxide (12.4%) emerging as the primary bioactive constituents. Acaricidal bioassays were performed utilizing the larval packet test across a suite of oil concentrations (5.0 to 25.0 mg/mL) over 24-hour exposure periods. The essential oil demonstrated significant lethal potency, yielding an LC50 value of 8.4 mg/mL and an LC90 value of 16.5 mg/mL against the tick larvae. A linear correlation was observed between the concentration of sesquiterpenes and larval mortality rates. This confirms that volatile sesquiterpenoids actively disrupt the respiratory and cuticle matrices of arachnid vectors, providing a sustainable botanical framework for veterinary parasite control.

Keywords: Vernonia amygdalina; Essential oils; GC-MS analysis; Beta-caryophyllene; Acaricidal bioassay; Rhipicephalus microplus

Manuscript Timeline: Received: April 02, 2018; Revised: May 15, 2018; Accepted: June 20, 2018; Published: January 03, 2019.

Citation: Abdulrahman, S. A., & Santos, L. E. G. O. (2019). Phytochemical Screening, Volatile Component Identification, and In Vitro Acaricidal Efficacy of Vernonia amygdalina Essential Oils. International Journal of Chemistry, 10(1), 1–8.

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