New saponins from Sechium mexicanum

• Published in: Magnetic resonance in chemistry Vol. 47; no. 11; pp. 994 - 1003
• Main Authors: Hernández-Carlos, Beatriz, Carmona-Pineda, Miriam, Villanueva-Cañongo, Claudia, López-Olguín, Jesús F., Aragón-García, Agustín, Joseph-Nathan, Pedro
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.11.2009; Wiley
• Subjects: 13C NMR; 1H NMR; Chemistry; Chemistry, Multidisciplinary; Chemistry, Physical; Cucurbitaceae - chemistry; Magnetic Resonance Spectroscopy - methods; Physical Sciences; Plant Extracts - chemistry; Plant Roots - chemistry; Saponins - chemistry; Saponins - classification; Science & Technology; Sechium mexicanum; Spectroscopy; Technology; triterpenoid saponins; triterpenoid saponins; GLYCOSIDES; SEEDS; CUCURBITACEAE; LEAVES; BISDESMOSIDES; ROOTS; Sechium mexicanum; H-1 NMR, C-13 NMR; CONSTITUENTS
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.2487

The chemical study of Sechium mexicanum roots led to the isolation of the two new saponins {3‐O‐β‐D‐glucopyranosyl (1 → 3)‐β‐D‐glucopyranosyl‐2β,3β,16α,23‐tetrahydroxyolean‐12‐en‐28‐oic acid 28‐O‐α‐L‐rhamnopyranosyl‐(1 → 3)‐β‐D‐xylopyranosyl‐(1 → 4)‐α‐L‐rhamnopyranosyl‐(1 → 2)‐α‐L‐arabinopyranoside} (1) and {3‐O‐β‐D‐glucopyranosyl (1 → 3)‐β‐D‐glucopyranosyl‐2β,3β,16α,23‐tetrahydroxyolean‐12‐en‐28‐oic acid 28‐O‐α‐L‐rhamnopyranosyl‐(1 → 3)‐β‐D‐xylopyranosyl‐(1 → 4)‐[β‐D‐apiosyl‐(1 → 3)]‐α‐L‐rhamnopyranosyl‐(1 → 2)‐α‐L‐arabinopyranoside} (2), together with the known compounds {3‐O‐β‐D‐glucopyranosyl‐(1 → 3)‐β‐D‐glucopyranosyl‐2β,3β,6β,16α,23‐pentahydroxyolean‐12‐en‐28‐oic acid 28‐O‐α‐L‐rhamnopyranosyl‐(1 → 3)‐β‐D‐xylopyranosyl‐(1 → 4)‐α‐L‐rhamnopyranosyl‐(1 → 2)‐α‐L‐arabinopyranoside} (3), tacacosides A1 (4) and B3 (5). The structures of saponins 1 and 2 were elucidated using a combination of 1H and 13C 1D‐NMR, COSY, TOCSY, gHMBC and gHSQC 2D‐NMR, and FABMS of the natural compounds and their peracetylated derivates, as well as by chemical degradation. Compounds 1–3 are the first examples of saponins containing polygalacic and 16‐hydroxyprotobasic acids found in the genus Sechium, while 4 and 5, which had been characterized partially by NMR, are now characterized in detail. Copyright © 2009 John Wiley & Sons, Ltd. Chemical study of Sechium mexicanum roots lead to the isolation of the two new saponins 1 and 2, together with three known compounds. The structures were elucidated using a combination of 1H and 13C 1D‐NMR, COSY, TOCSY, gHMBC and gHSQC 2D‐NMR, and FABMS of the natural compounds and their peracetylated derivates, as well as by chemical degradation.