Models of estimation of the content of secondary metabolites in some Hypericum species

Abstract

In the present study, models for estimation of the content of main secondary metabolites, namely hypericin, pseudohypericin, and hyperforin, were developed for Hypericum origanifolium Willd. (Guttiferae), Hypericum perfoliatum L., and Hypericum montbretii Spach., growing in Northern Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting, and mature fruiting stages and dissected into stem, leaf, and reproductive tissues. Actual secondary metabolite contents of plant materials were measured by a high performance liquid chromatography method. Multiple regression analysis using the Excel 2003 computer package was performed for each species and chemical separately to develop multiple regression models. The equation produced for predicting the content of secondary metabolites in different tissues of the species was formulized as: SMC = [a + (b1 × S) + (b2 × L) + (b3 × RP) + (b4 × S²) + (b5 × (1/RP))], where SMC is the secondary metabolite content of the whole plant, S is the secondary metabolite content of the stem, L is the secondary metabolite content of the leaf, RP is the secondary metabolite content of the reproductive parts, and a, b1, b2, b3, b4, and b5 are coefficients. The R2 coefficient values between predicted and observed contents of secondary metabolites were determined as 0.99 for H. origanifolium, 0.95–0.98 for H. perfoliatum, and 0.90–0.99 for H. montbretii. All R² values and standard errors were found to be significant at the p < 0.05 level.