Bioactive Constituent and Eugenol Synthase 1 Gene of Thai Red Holy Basil (Ocimum tenuiflorum L.)

Abstract

Red holy basil (Ocimum tenuiflorum L.) is a commonly grown herb crop with diverse cultivars/accessions that contain highly ranked bioactive substances for medicinal potentialities. In this study, bioactive constituents and eugenol synthase 1 (EGS1) were characterized in Thai red holy basil. The compositions of the bioactive distilled from dried and fresh leaves and dried flower spikes were determined using headspace–solid phase microextraction–gas chromatography. Furthermore, a full-length of putative EGS1 was cloned from Thai red holy basil leaf tissue. The open reading frame of EGS1 contained 945 bp and encoded a 314-amino acid sequence. Phylogenetic analysis clearly distinguished two homology classes of EGS. EGS1 of red holy basil was closely related to that of white holy basil and lemon basil. Additionally, EGS1 expression in leaf tissue at the flowering stage was further assessed in ten local red holy basil accessions. EGS1 transcript levels were high, especially in aroma-rich accessions. EGS1 was expressed at higher levels in leaves than in flower spikes. Our study characterizes red holy basil in terms of both biochemical and gene information. This information can be used for further studies focusing on gene editing to increase the production of high-quality Thai red holy basil for the food and pharmacological industries.