Isolation and identification of sapotexanthin 5,6-epoxide and 5,8-epoxide from red mamey (Pouteria sapota).

Enrique Murillo,Johant Lakey‐Beitia,Attila Agócs,József Deli,Veronika Nagy,Tibor Kurtán,Eunice Molinar Toribio,Sándor Balázs Király

doi:10.1002/chir.23206

Abstract

Two new carotenoids, sapotexanthin 5,6-epoxide and sapotexanthin 5,8-epoxide, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Sapotexanthin 5,6-epoxide was also prepared by partial synthesis via epoxidation of sapotexanthin, and the (5R,6S) and (5S,6R) stereoisomers were identified by high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) analysis. Spectroscopic data of the natural and semisynthetic derivatives obtained by acid-catalyzed rearrangement of cryptocapsin 5,8-epoxide stereoisomers were compared for structural elucidation.

Highlights

| INTRODUCTION[This article is part of the Special Issue: In honor and memory of Prof. Koji Nakanishi
Bouvier et al showed that in paprika extract, kappa carotenoids are biosynthesized from 5,6-epoxy carotenoids and the reaction is catalyzed by the capsanthincapsorubin synthase (CCS) enzyme.[9]
The extraction of mamey pulp was accomplished with published procedures.[10]

Summary

| INTRODUCTION

[This article is part of the Special Issue: In honor and memory of Prof. Koji Nakanishi. Group are not so common in nature, and they usually contain a hydroxylated ring, as in capsanthin, capsorubin, and cryptocapsin. The main carotenoids were cryptocapsin (1), sapotexanthin (2), and capsanthin 5,6-epoxide (3). The pulp of red mamey contains several other interesting red carotenoids associated with hydroxylated or nonhydroxylated κ-rings. Bouvier et al showed that in paprika extract, kappa carotenoids are biosynthesized from 5,6-epoxy carotenoids and the reaction is catalyzed by the capsanthincapsorubin synthase (CCS) enzyme.[9] The biosynthesis of capsanthin, capsorubin, and cryptocapsin (1) starts from antheraxanthin, violaxanthin, and β-cryptoxanthin 5,6-epoxide, respectively. Carotenoids containing a 5,6-epoxide unit in the nonhydroxylated β-ring have rarely been reported. This paper reports the isolation and structural elucidation of the new carotenoid sapotexanthin 5,6-epoxide (6) and its 5,8-derivatives

| MATERIALS AND METHODS

| RESULTS AND DISCUSSION

| CONCLUSION