Polyphenol Profile and Quantitative Assessment of the Flavonoid Kaempferitrin in Wild and Cultivated Brazilian Amazonian Uncaria guianensis (Rubiaceae)

Djavan Da Paixão,Antonio Siani,Luis Berrueta,Blanca Gallo,Rodolfo Barboza,Ligia Valente,Rita Pereira,Matheus Souza

doi:10.21577/0103-5053.20210064

Abstract

The Amazonian Rubiaceae species Uncaria guianensis (UG) is locally used as antiinflammatory, antitumor, antidiabetic, anti-ulcers, and others. The phenolic content of its leaves is characterized by the great predominance of the flavonoid kaempferol-3,7-O-(α)-L-dirhamnoside (kaempferitrin). The present study quantitatively evaluates the kaempferitrin content in the leaves and branches of cultivated and wild UG specimens collected in different locations of the Brazilian Amazon rainforest by employing high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD). Besides, the understanding of the polyphenol profile performed by electron spray ionization is deepened by tandem mass spectrometry analysis (ESI-MS/MS), using a previously approached leaf UG extract, and the flavonoid quercetin-3,7-O-(α)-L-dirhamnoside was first isolated from UG. All samples showed quite similar qualitative polyphenol profiles. Kaempferitrin in UG ranged from 1.1 to 1.9 mg 100 mg-1 for dry leaves of adult wild plants, 0.3 to 0.7 mg 100 mg-1 for dry leaves of cultivated young plants and 0.00 to 0.04 mg 100 mg-1 for dry branches of adult wild plants. Besides suggesting the distribution of kaempferitrin in the species, these results reinforce this flavonol as a suitable chemical marker for UG leaves and the products derived from them.

Highlights

The genus Uncaria (Rubiaceae) contains about 60 species distributed in the tropical areas of Southeast Asia, Africa and Central and South America.[1,2] It is represented in Central and South America by two species: U. tomentosa (Willd.) DC and U. guianensis (Aubl.) Gmel.[3]
We have reported that the flavonol kaempferitrin (5) (kaempferol-3,7-O-(α)-L-dirhamnoside) was isolated for the first time from the Uncaria species detected in leaves and branches of U. guianensis but not in U. tomentosa.[21]
The selective presence of kaempferitrin in the U. guianensis leaves collected in the state of Mato Grosso has previously been established by high-performance liquid chromatography (HPLC)-DAD-mass spectra (MS) upon an anti-inflammatory and anti-allergic EtOH extract.[21]

Summary

Introduction

The genus Uncaria (Rubiaceae) contains about 60 species distributed in the tropical areas of Southeast Asia, Africa and Central and South America.[1,2] It is represented in Central and South America by two species: U. tomentosa (Willd.) DC and U. guianensis (Aubl.) Gmel.[3]. The leaves of U. guianensis showed antibacterial activity[15] while the bark slowed antitumor effects.[18]

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Results

Conclusion