Physical-Chemical Characterisation and Biological Activities of the Essential Oil of Lippia alba (Mill) NE Br Ex Britton Obtained in Ecuador

Abstract

Introduction

Lippia alba is a wild semishrubby species that grows in countries like Ecuador, its extracts have significant bioactive compounds. However, the antioxidant and antimicrobial properties of L alba essential oil (EO) have not been given importance in this region. The present study aimed to evaluate the physicochemical characteristics of the extracts and biological activities of L alba EO.

Methods

A unifactorial design was used, and physicochemical variables (pH, density, and refractive index) and antioxidant and antimicrobial capacities were explored using standard methods. Fractions of L alba EO were analysed by gas chromatography-mass spectroscopy.

Results

The density, pH, refractive index, and phenolic content of L alba EO were found to be 0.95 g/ml, 5.5, 1.51, and 918 mg/l, respectively. An antioxidant activity of 23.08 mg/l was observed by the 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic) method, while 14.81 mg/l was observed by the ferric reducing antioxidant power method. Essential oil of L alba has presented a greater antimicrobial activity against different Gram-negative than Gram-positive bacteria. Essential oil of L alba showed an inhibitory zone of 56.7 and 9.7 mm against Photobacterium damselae sub sp. piscicida DSM 22834 and Bacillus subtilis ATCC 6633, respectively.

Conclusions

The results of the present investigation clearly indicated that the EO of L alba has potential antioxidant and antimicrobial activities in vitro analysis, which are important indications that this extract can be applied in different industries, such as pharmaceutical industry, food industry, and others.