Quantitative determination of shikonin derivatives with UV-Vis spectrophotometric methods in the roots of Onosma nigricaule

Abstract

The genus Onosma is represented by 97 species, 4 varie­ties, 1 hybrid species in the flora of Turkey. Some Onosma species with roots containing naphthoquinones (alkannin, shikonin and alkannin/shikonin derivatives) are known as “Havaciva” in Turkey. Onosma nigricaule is an endemic species for Turkey. The roots of O. nigricaule are used for wounds and burns in Erzurum (Turkey). In this study, quantitative determination of shikonin derivatives (deoxyshikonin, β,β-dimethylacrylshikonin and acetyl shikonin) isolated from the roots of O. nigricaule was performed using a UV-Vis spectrophotometric method. The isolated shikonin derivatives have shown three maxima at 493 nm, 523 nm and 562 nm. The mean absorption coefficient of the three shikonin derivatives (deoxyshikonin, β,β-dimethylacrylshikonin and acetyl shikonin) was determined at 523 nm and 562 nm as 15.27 l/g cm and 9.39 l/g cm, respectively. The total content of shikonin derivatives were determined as 214.6 mg/100 g root at 523 nm and 220.6 mg/100 g root at 562 nm by using mean absorption coefficient of the three shikonin derivatives (deoxyshikonin, β,β-dimethylacrylshikonin and acetyl shikonin).

Keywords

• boraginaceae
• onosma
• onosma nigricaule
• shikonin derivatives
• uv-vis spectrophotometry