valmane and valtrate

Valepotriates are iridoids found in variable amounts in Valerianaceae and might be among the bioactive compounds which confer anxiolytic properties to the Valeriana species. On the other hand, unspecific cytotoxicity has also been described. Presently, however, no particular molecular target has been defined for these compounds. Here we studied the effect of valtrate, acevaltrate, and 1- β-acevaltrate isolated from Valeriana glechomifolia on the enzymatic activity of rat P-type ATPases. Valepotriates did not affect rat skeletal muscle sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) activity at the highest concentration used (100 µM). In contrast, the same concentration inhibited roughly half of the total H⁺/K⁺-ATPase activity from rat gastric epithelium (valtrate 54.6 ± 3.2 %, acevaltrate 60.7 ± 7.3 %, 1- β-acevaltrate 50.2 ± 3.1 %; mean ± SEM, n = 3-5). Finally, these substances showed the highest inhibitory potency toward Na⁺/K⁺-ATPase, and the inhibition curves obtained provided a similar IC₅₀ (in µM) for rat kidney α1 isoform (valtrate 21.2, acevaltrate 22.8, 1- β-acevaltrate 24.4) and brain hemispheres α2/ α3 isoforms (valtrate 19.4, acevaltrate 42.3, 1- β-acevaltrate 38.3). Our results suggest that P-type ATPases are differentially inhibited by valepotriates and that Na⁺/K⁺-ATPase might be one of their molecular targets in vivo.

Topics: Adenosine Triphosphatases; Animals; Brain; Epithelium; H(+)-K(+)-Exchanging ATPase; Inhibitory Concentration 50; Iridoids; Kidney; Male; Rats; Rats, Wistar; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Sodium-Potassium-Exchanging ATPase; Stomach; Valerian

Valeriana glechomifolia is a plant species endemic to southern Brazil that accumulates valepotriates, which are terpene derivatives, in all of its organs. Valepotriates are the presumed sedative generic components of the pharmaceutically used species of Valeriana. The influence of various concentrations of the auxins indole-3-acetic acid, indole-3-butyric acid and alpha-naphthaleneacetic acid on the growth of micropropagated V. glechomifolia was investigated under conditions of transient and continuous exposure. Changes in the development of roots and shoots as well as the production of the valepotriates acevaltrate, valtrate and didrovaltrate (analyzed by high-performance liquid chromatography) were evaluated. The best performance in valepotriate production, growth and survival under ex vitro conditions following plant acclimatization was achieved in the continuous presence of 5.71 microM IAA. When cultured in medium containing IAA plants produced stable levels of valepotriates throughout the entire cultivation period.

Topics: Acclimatization; Indoleacetic Acids; Indoles; Iridoids; Naphthaleneacetic Acids; Plant Roots; Plant Shoots; Valerian

Valtrate, DIA-valtrate, acevaltrate, 1-beta-acevaltrate and didrovaltrate have been quantitatively estimated by reversed-phase HPLC in the leaves, flowers, stems and roots of Valeriana glechomifolia Meyer, V. catharinensis Graebn., V. chamaedryfolia Cham. & Schltdl., V. eichleriana (C.A.Mull.) Graebn., V. polysthachya Smith, V. scandens L., V. eupatoria Sobral, V. salicariifolia Vahl and V. tajuvensis Sobral. All plants presented valepotriates being V. glechomifolia the richest one, followed by V. eupatoria, V. eichleriana and V. tajuvensis.

Topics: Brazil; Chromatography, High Pressure Liquid; Iridoids; Plant Extracts; Plant Leaves; Plant Roots; Plant Stems; Pyrans; Valerian