Anatomical characters of the medicinal leaf and stem of Gymnanthemum amygdalinum (Delile) Sch.Bip. ex Walp. (Asteraceae)

Márcia Do Rocio Duarte,Ariane Gonçalves Silva

doi:10.1590/s1984-82502013000400011

Márcia Do Rocio Duarte, Ariane Gonçalves Silva

Open Access

https://doi.org/10.1590/s1984-82502013000400011

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Abstract

Gymnanthemum amygdalinum (Delile) Sch.Bip. ex Walp. (Asteraceae), better known by its former name Vernonia amygdalina Delile, is a small shrub used in folk medicine as an antipyretic, laxative, antimalarial and anthelmintic. Studies have demonstrated that different vegetal extracts possess antioxidant, antimicrobial and antiparasitic activities. Among the bioactive metabolites, there are sesquiterpene lactones, saponins, polyphenols and flavonoids. This study investigated the leaf and stem microscopic characters of G. amygdalinum, aiming to expand the knowledge on this medicinal species and indicate anatomical structures. Plant material was fixed and sectioned by freehand and using a microtome. The sections were either stained or underwent standard histochemical tests. Scanning electron microscopy was performed to investigate epidermal relief. The leaf is amphistomatic with anomocytic stomata. There are striate cuticle, glandular and non-glandular trichomes and dorsiventral mesophyll. In transverse section, the midrib and the petiole have a plano-convex shape. Both show several collateral vascular bundles and few crystals of calcium oxalate. In the stem, the epidermis persists and the phellogen has a peripheral origin. It presents typical endodermis and sclerenchymatic caps adjoining the phloem. The aspects that contribute to characterizing the species are stomata on both leaf surfaces, midrib and petiole features, the endodermis and sclerenchymatic caps in the stem, as well as the different types of trichome on both aerial organs.

Highlights

Gymnanthemum amygdalinum (Delile) Sch.Bip. ex Walp. (Asteraceae), formerly known as Vernonia amygdalina Delile, is a small shrub commonly called bitterleaf due to its peculiar taste (Momoh et al, 2012)
Gymnanthemum amygdalinum displayed features in common to many medicinal species of this family, such as leaf with uniseriate epidermis, dorsiventral mesophyll, simple arc of collateral vascular bundles in the midrib and petiole, as well as stem with peripheral development of the phellogen, outer cortex consisting of collenchyma, well defined endodermis and crescent-shaped strands of sclerenchyma at the outer boundary of the phloem
With species of Vernonia, since G. amygdalinum was formerly circumscribed to this taxon

Summary

Introduction

Gymnanthemum amygdalinum (Delile) Sch.Bip. ex Walp. (Asteraceae), formerly known as Vernonia amygdalina Delile, is a small shrub commonly called bitterleaf due to its peculiar taste (Momoh et al, 2012). In Brazil, this species is referred to as alumã, boldo or alcachofra (Agra et al, 2008; Coelho-Ferreira, 2009; Almeida et al, 2012). It has an erect stem covered with white hairs, ovate-lanceolate to elliptic-lanceolate leaves with short petiole, and creamy-white inflorescences (Achigan-Dako et al, 2009). Studies of different extracts have shown antioxidant (Igile et al, 1994; Farombi, Owoeye, 2011), antimicrobial (Erasto, Grierson, Afolayan, 2006; Okigbo, Mmeka, 2008), antiparasitic (Tadesse et al, 1993; Ademola, Eloff, 2011; Adiukwu, Amon, Nambatya, 2011), antidiabetic (Akinola et al, 2011; Ong et al, 2011) and antihypertensive (Ajibola, Eleyinmi, Aluko, 2011; Saliu et al, 2011) properties

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