Chromatographic analysis of flavonoids and phenolic acids in the herb Ocimum sanctum L.

Abstract

The genus Basil (Ocimum L.), which belongs to the Mint (Lamiaceae Martinov) family, includes more than 70 species and several subspecies of herbaceous plants and subshrubs. In wild nature, they are common on almost all continents in tropical and subtropical regions, less often in temperate climates. Holy basil (Ocimum sanctum L.) is most often used in folk medicine of various countries. The medicinal properties of this plant are determined mainly by the essential oil and polyphenols. As it is known, the chemical composition of plant raw materials can vary significantly depending on genetic characteristics (subspecies, chemotype) as well as on soil and climatic conditions during its cultivation. This study aimed to determine the chromatographic profile of flavonoids and phenolic acids in the Ocimum sanctum herb during its cultivation in the conditions of the Ternopil Region (Ukraine). The aerial part of the studied plant was harvested at the beginning of flowering in the summer of 2023. The dried raw material was crushed and sifted through a sieve. The chromatographic profile of flavonoids and phenolic acids was determined by high-performance liquid chromatography (HPLC) using an Agilent Technologies 1200 chromatograph. The raw material was extracted using 80% methanol in an ultrasonic bath. Identification and quantitative analysis were carried out using solutions of standard samples of flavonoids and phenolic acids. Calibration was carried out by the method of external standards. It was revealed that the Ocimum sanctum herb contains eight phenolic acids, among which hydroxycinnamic rosmarinic acid (10 453.48 μg/g) dominated. In general, the content of hydroxycinnamic acids in the raw material of the studied species was significantly higher than that of hydroxybenzoic acids. Among the six identified flavonoids, the highest content was determined for the flavanone neohesperidin (11 720.79 μg/g); the content of other flavonoids, in particular, flavonol derivatives (quercetin, rutin, quercetin-3-O-glycoside, kaempferol-3-O-glycoside) and flavone (luteolin) was significantly lower. Considering the significant therapeutic potential of the predominant phenolic compounds, the planning of further pharmacological studies of phytosubstances based on the raw material of the studied species deserves attention.