Elucidation of Alcaloids Contained in the Fec5 Fraction of Bark of Annickia Chlorantha

Research Article

Austin J Anal Pharm Chem. 2023; 10(2): 1162.

Elucidation of Alcaloids Contained in the Fec5 Fraction of Bark of Annickia Chlorantha

Aimé Bertrand Madiélé Mabika1,3,4; Arnaud Wenceslas Geoffroy Tamba Sompila4,5*; Arnold Murphy Elouma Ndinga1; Huguette Agnaniet2; Valery Thiery3; Jean Maurille Ouamba1

1Unit of Life and Plant Chemistry (UC2V), Marien Ngouabi University, Brazzaville Congo

2Laboratory of Natural Substances and Organometallic Synthesis (LASUNSO), University of Sciences and Techniques of Masuku, Franceville Gabon

3Coastline Environment and Society (LIENs), University of La Rochelle, France

4National Institute for Research in Engineering Sciences, Innovation and Technology, Scientific City, Brazzaville Congo

5Laboratory of Food and Medical Bioprocesses, National Polytechnic School, Marien Ngouabi University, Brazzaville Congo

*Corresponding author: Arnaud Wenceslas Geoffroy Tamba Sompila Unit of Life and Plant Chemistry (UC2V), Marien Ngouabi University, Brazzaville Congo. Tel: +242 06.662.87.91 Email: arnaud.wens@gmail.com

Received: September 04, 2023 Accepted: October 31, 2023 Published: November 07, 2023

Abstract

The aim of this study was to highlight the presence in the barks of A. chlorantha, new alkaloids not yet identified in the literature. FEC5 fractionation method by semi-preparative HPLC revealed twelve (12) sub-fractions. Of these twelve sub-fractions, five were exploited. These five sub-fractions EC3, EC9, EC10, EC11 and EC12 revealed fifteen (15) alkaloids which were isolated, designated by the letters A to O, and identified mainly by mass spectrometry. The results obtained allowed us to note that the alkaloidal composition of the plant, especially of the barks, is still very poorly elucidated. The isolated alkaloids belong, for the most part, either to the group of protoberberines and tetrahydroprotoberberines or to the bisbenzyltetrahydro isoquinolines which have not yet been reported in the literature. The isolation of palmatine corroborated the results of the literature. These results showed that these sub-fractions are not totally pure. They are a mixture of compounds. The complexity of the alkaloid composition of Annickia chlorantha trunk bark is particularly justified by the number of alkaloids present.

Keywords: Bisbenzyltetrahydroisoquinoleines; Extraction; Fractionation; Isolation; Purification; Tetrahydroprotoberine

Nomenclature: FEC: Fraction Annickia chlorantha; EC: Subfraction Annickia chlorantha; TLC: Thin Layer Chromatography; HPLC: Hight Performance Liquid Chromatography; UV: UltraViolet; NMR: Nuclear Magnetic Resonance; SMHR: High Resolution Mass Spectrometry; DRC: Democratic Republic of Congo; HIV: Human Immunodeficiency Virus

Introduction

Plants have been used in traditional medicine for many millennia. Curiosity is the innate principle of the doctrine that, indicating the possibility of identifying the peculiarities and virtues of each plant by its signature, guided the first men in the choice of new preparations to be tested [1]. In the last decades there has been a growing interest in the study of medicinal plants and their traditional use in different regions of the world [2]. Today, according to the World Health Organization (WHO), nearly 80% of the population depends on traditional medicine for primary health care. Considerable economic advantages in the development of traditional medicine and in the use of medicinal plants for the treatment of various diseases have been noted world [2], hence the need to valorize traditional medicine and especially the molecules extracted from plants. In these plants, we find primary and secondary metabolites. The primary metabolites are in great number whereas the secondary metabolites are molecules having a limited distribution in the plant. The secondary metabolites play different roles, including that of defense against external aggressions. Secondary metabolism products are very numerous; more than 200.000 structures defined [3]. They include an extraordinary structural variety but are produced in small quantities [3]. These molecules mark in an original way, a species, a family or a genus of plant and sometimes allow to establish a chemical taxonomy. Phenolic compounds, terpenoids, steroids and alkaloids are examples of secondary metabolites; they have many pharmaceutical applications [3].

Annickia chlorantha, a plant belonging to the Annonaceae family, is one of the warm and humid climate species of tropical Africa that grows in dense forest usually at low altitude. Geographically, it is found widespread in southern Nigeria, Angola, the Republic of Congo and the Democratic Republic of Congo [4]. A. chlorantha has been the subject of several chemical and pharmacological studies [5] and this revealed that it contains alkaloids. Some parts of the plant, especially the bark and the roots, contain alkaloids with an anti-hepatitis effect. This is a property long recognized in traditional medicine [6]. The extracts of bark of A. chlorantha are used in the manufacture of a drug, having a preventive and curative effect on viral hepatitis [7]. The alkaloids isolated from this plant are active against Trypanosoma cruzi, the American trypanosomiasis pathogen [8]. The plant’s barks are also traditionally used for the treatment of rheumatism, fatigue, tuberculosis and certain ulcers [9], malaria and for deworming [10]. They are also used against diarrhea [10]. In addition, [9] revealed the anti-HIV properties of the aqueous extract of this plant. The use of the sulfur yellow bark provides an excellent dye used in the dyeing of fabrics, skins and mats in some regions, especially in Cameroon, Congo, Gabon and DRC [11,12]. The literature reports that A. chlorantha contains palmatin in the stem and root barks [13]. In 1975, the chemical constituents of barks were elucidated [14]. Several alkaloids were isolated [6,9]. The main alkaloids extracted from the trunk bark are quaternary protoberberines, such as palmatine, berberine, jatrorrhizine and columbamine. Two new alkaloids have been identified, namely aporphine and another alkaloid of the protoberberine type (active anti-HIV alkaloid), 7.8-dihydro-8-hydroxypalmatine have also been isolated from the bark [9].

In the same way, we have set ourselves the goal of extracting, purifying and isolating by chromatographic methods, two alkaloids of the protoberberine type and thirteen alkaloids of the bisbenzyl tetrahydrobenzyl isoquinoline types.

Materiel and Methods

Plant Material

The plant of Annickia chlorantha was collected in November 2012 in the department of Niari precisely in Mossendjo in southwestern Congo. The part used in this study consisted of the bark kept in the dark at room temperature (25 °C) for about five (05) days. The dry matter was then ground with an IKA-WERKE Gmbh-CO-KG, D-79219 Staufen, equipped with a 0.25 mm sieve.

Fractionation and Purification of Dye Extracts

Experimental Approach

The experimental approach (Figure 2) allowed for fractionation and purification of the dye extracts.