Chemical composition, antioxidant activities and antibacterial activities of essential oil from Erythrina caffra Thunb. growing in South Africa

Olubunmi A Wintola; Aderonke A Olajuyigbe; Anthony J Afolayan; Roger M Coopoosamy; Olufunmiso O Olajuyigbe

doi:10.1016/j.heliyon.2021.e07244

Chemical composition, antioxidant activities and antibacterial activities of essential oil from Erythrina caffra Thunb. growing in South Africa

Heliyon. 2021 Jun 7;7(6):e07244. doi: 10.1016/j.heliyon.2021.e07244. eCollection 2021 Jun.

Authors

Olubunmi A Wintola¹, Aderonke A Olajuyigbe², Anthony J Afolayan¹, Roger M Coopoosamy³, Olufunmiso O Olajuyigbe³

Affiliations

¹ Medicinal Plants and Economic Development (MPED) Research Centre, Botany Department, University of Fort Hare, Alice Campus, South Africa.
² Department of Microbiology, School of Science & Technology, Babcock University, PMB 4005, Ilisan-Remo, Ogun State, Nigeria.
³ Department of Nature Conservation, Faculty of Natural Sciences, Mangosuthu University of Technology, P.O.Box 12363, Jacobs, 4026, Durban, Kwa-Zulu Natal, South Africa.

Abstract

Introduction: Essential oils from plants are recognized as one of the most promising secondary metabolites for the development of cheap and safer drugs. While Erythrina caffra has been prominently used in folk medicine for the treatment of microbial infections, there is dearth of information on the pharmacological effectiveness and chemical composition of its essential oil. The study, therefore, aimed at identifying the chemical composition and biological activities of the essential oil of Erythrina caffra.

Methods: In this study, the essential oil was extracted with all-glass Clevenger. The antioxidant activities of the essential oil and antibacterial susceptibility assay by agar well diffusion techniques were assessed while GC-MS analysis was performed to identify the chemical constituents of the essential oil.

Results: The study showed that the radical scavenging activity of the essential oil increases as the concentration of the essential oil increases. All bacterial isolates were susceptible to essential oil with the exception of Salmonella typhimurium and Pseudomonas aeruginosa producing inhibition zones ranging between 22 ± 1.3 and 35 ± 2.1 mm in the susceptible isolates. The GC-MS chromatogram indicated there are 35 bioactive compounds in the essential oil and Caryophyllene oxide (53.54%), [1S-(1α,7α,8aβ)]-1,2,3,5,6,7,8,8a-octa-1 - hydro-1,8a-dimethyl-7-(1-methylethenyl)-Naphthalene (7.81%), Kauran-18-al (6.49%), 10,10-Dimethyl-2,6-dimethylenebicy clo[7.2.0]undecan-5.beta.-ol (5.83%), 10s,11s-Himachala-3(12),4-diene (4.51%), Caryophyllene (3.65%) and 1- Hexanol (3.31%) were the most prominent compounds.

Conclusion: Excessive production of free radicals or reactive oxygen species (ROS) causes oxidative stress and disease. Oxidative stress resulting from imbalance between excessive generation of free radicals and inadequate antioxidant defense system has been linked to pathogenesis of many diseases. The essential oil of E. caffra stem bark extract possess antimicrobial and good antioxidant activities and its rich level of phytochemicals can be used as either dietary or complementary agents.

Keywords: Antibacterial; Antioxidant; Bioactive compounds; Caryophyllene oxide; GC-MS analysis; Phytochemicals; Susceptibility.