Quantification of Barbatusin and 3β-Hydroxy-3-deoxybarbatusin in Plectranthus Species by HPLC-DAD

Abstract EN

The concentration of diterpenes barbatusin (1) and 3β-hydroxy-3-deoxybarbatusin (2) in the extracts from leaves of Plectranthus grandis, P.

barbatus, P.

ornatus, and P.

amboinicus was evaluated by HPLC-DAD analysis on a Luna C-18 column, using isocratic mixtures of water and acetonitrile as eluents.

The regression equations were obtained with good linearity (r2 > 0.99) and limit of quantifications was higher than 0.1 µg/mL.

The precision (lower than 3.5%, within day) and accuracy (higher than 81.7% and lower than 107.6%) of the methods were adequate.

Barbatusin (1) was detected in P.

grandis (15.432 ± 2.28 mg/g) and P.

barbatus (5.198 ± 3.45 mg/g) extracts, while compound 2 was detected in P.

grandis (4.068 ± 3.34 mg/g), P.

barbatus (0.654 ± 5.86 mg/g), P.

amboinicus (0.160 ± 7.25 mg/g), and P.

ornatus (0.763 ± 5.10 mg/g).

The evaluated validation parameters were satisfactorily achieved, and the developed methodology represents a suitable tool for application in the quantification of barbatusin (1) and 3β-hydroxy-3-deoxybarbatusin (2) in Plectranthus species.