Homoorientin from Phlomis tuberosa

HOMOORIENTIN FROM N . K. V a v i l o v a Phlomis tuberosa a n d l~. V. G e l l a UDC 547.972 Continuing an investigation of the polyphenolic substances f r o m Phlomis t u b e r o s a (L.) Sp. pl. (family Labiatae Juss.), in addition to orientin and cynaroside, which have been isolated previously, we obtained homoorientin (liD. To isolate it, the epigeal part of the plant collected in June, 1972, in the flowering period in the environs of the town of Kursk was e x t r a c t e d with 80% ethanol with subsequent purification and s e p a r a tion on polyamide sorbent. Substance (I~), with the composition C21H22Oll, a f t e r additional purification on Kapron consisted of yellow needles with mp 234-235°C, R f 0.29 (15% acetic acid, s y s t e m 1), 0.37 [ b u t a n - l - o l - a c e t i c a c i d - w a t e r (4 : 1 : 5 ) , s y s t e m 2]; ~'max in ettganol: 250, 270, 352 nm; with z i r c o n i u m nitrate: 280, 330, 412 nm. The magnitude of the bathochromic shift with z i r c o n i u m nitrate shows the site of attachment of the c a r b o hydrate residue to be position 6 o r 8 in the f o r m of a C-glycoside. The 60-nm bathochromic shift of the f i r s t band c h a r a c t e r i z e s substitution at position 8, which a g r e e s with l i t e r a t u r e information. The hydrolysis of substance (III) with a 10% solution of HC1 led to two substances: the starting mat e r i a l and a substance with R f 0.16 (system 1) and 0.32 (system 2) which was identical with the orientin isolated previously. The iso~ner was detected a f t e r hydrolysis for 30 min: on more prolonged hydrolysis (more than 4 h) the equilibrium shifted in the direction of substance OID. Acid hydrolysis according to KUiani [2] of the compound under investigation gave the aglycone, with mp 328-330°C, R f 0.90 (system 2), identified as luteolin. The carbohydrate moiety consisted of D-glucose with a small amount of D-arabinose. The appearance of the l a t t e r is c h a r a c t e r i s t i c for the hydrolysis of C-glycosides and can be explained by the assumption that bond cleavage takes place not only between the c a r b o h y d r a t e substituent and the aglycone but also between the f i r s t and second carbon atoms of the sugar. The yield of the aglycone (63%) shows that the glycoside under investigation is a monooside. The IR s p e c t r u m has absorption bands at 1082, 1056, 890, and 835 c m -1, showing that the D-glucose is attached to the aglycone by a fl-glycosidic bond and is p r e s e n t in the pyranose f o r m , which is confirmed by the n u m e r i c a l values of [M] D • Kp (+74.3) calculated by KlyneTs method [3]. A mixture of the m a t e r i a l under investigation with an authentic sample of homoorientin (luteolin 8-Canti-fl-D-glucopyranoside) gave no d e p r e s s i o n of the melting point. LITERATURE lo 2. 3. CITED N. P. Maksyutina and V. I. Litvinenko, in: Phenolic Compounds a n d T h e i r Biological Functions [in Russian], Moscow (1968), p. 7. H. Kiliani, B e r . , 63, 2866 (1930). I. P. Kovalev and V. I. Litvinenko, Khim. P r i r o d n . Soedin., 233 (1965). Kursk Medical Institute. T r a n s l a t e d f r o m Khimiya P r i r o d n y k h Soedinenii, No. 2, pp. 285-286, M a r c h April, 1973. Original a r t i c l e submitted D e c e m b e r 12, 1972. © 19 75 Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 1001 I. No part o f this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of the publisher. A copy o f this article is available from the publisher for $15.00. 282  (...truncated)