PHYTOCHEMICAL AND PHARMACOGNOSTIC STUDIES OF TELOSMA AFRICANUM (N.E.Br) COLVILLE LEAF AND STEM

PHYTOCHEMICAL AND PHARMACOGNOSTIC STUDIES OF TELOSMA AFRICANUM (N.E.Br) COLVILLE LEAF AND STEM

Fred-Jaiyesimi Adediwura* and Adisa Ayotunde

Department of Pharmacognosy, Faculty of Pharmacy, Olabisi Onabanjo University, Sagamu Campus, Ago-Iwoye, Nigeria

ABSTRACT

Telosma africanum (N.E.Br) Colville (Ascelpiadaceae) is a slender riverine and deciduous climber used traditionally in the treatment of venereal diseases.  Using standard procedures, the pharmacognostic studies, fluorescence analysis and phytochemical screening were carried out.  This study revealed the presence of combined Anthraquinone, Saponin, Cardiac glycoside, alkaloids in the leaf and stem. Flavonoid as well as uniseriate trichomes and anisocytic type of stomata were present in the leaf.

Telosma africanum, Uniseriate, Anisocytic, Fluorescence, Phytochemical

INTRODUCTION:Telosma africanum (N.E.Br) Colville (Ascelpiadaceae) is commonly known as the African Telosma.  It is a slender climber found in the riverine and deciduous forests mainly Guinea, West Cameroun and dispersed in tropical Africa, as well as from the South to Natal ¹.

In the folklore medicine of the Tanganyika, the fresh roots of T. africanum is shaken in water and drank as a vermifuge and for venereal disease ¹.

There is however very scanty information on the ethnobotanical uses, pharmacognostic and biological studies of T. africanum.  This study aims at evaluating the pharmacognostic studies of the leaf, fluorescence analysis as well as the phytochemical screening of the leaf and stem.

MATERIALS AND METHODS: The leaves and stem of T. africanum were collected from Onigambari Forest, Ago-Iwoye.  Nigeria and authenticated at the Forestry Research Institute of Nigeria (FRIN).

Chemicals and Instruments: Compound microscope, glass and cover slips.  All chemicals and reagents used were of analytical grade.

Phytochemical Studies: The Phytochemical screening of the leaf and stem of T. africanum was carried out using standard procedures ^{2- 3}.

Pharmacognostical Investigation: Morphological Features:  The morphological features of the leaves such as the odour, colour, size, shape and taste were studied ⁴.

Microscopy: The sections for microscopy were prepared by free hand section of the leaf  which was cleared with chloral hydrate and mounted in glycerine ^5-6.

Fluorescence analysis:  The fluorescence analysis of the powdered leaf and stem of T. africanum were carried out using various solvents ^{7- 8}.

RESULTS AND DISCUSSION: Telosma africanum belongs to the family Ascelpiadaceae, a family characterised by about 250 genera and 2000 species ⁹. In this study, the macroscopy of the leaf showed that the leaves of T. africanum are dark green, simple, tasteless, with the lamina about 14.2 long and 22.5cm broad.  The shape of the leaf is ovate, acuminate at apex, cordate at base and entire along margin.  Table 1.

TABLE 1: MACROSCOPIC CHARACTERISTICS OF FRESH T. AFRICANUM LEAF

Length: Breadth   14.2cm; 22.5cm

Previous studies have reported that the main type of stomata found in the family ascelpiadaceae is the paracytic type with only some species possessing anomocytic or anisocytic types ⁹. In this study, the microscopic study revealed that the leaf of T. africanum possess the anisocytic (cruciferous) type of stomata characterised by three subsidiary cells with one smaller than the others (Fig. 1).

In addition, the leaf possesses uniseriate hairs with pointed apex (Fig. 1) and a dorsiventral structure of the leaf midrib (Fig. 2).

The fluorescence analysis is helpful in the characterization of crude drugs ¹⁰ and further reveals the presence of active agents in the leaf and stembl by their various colour reactions to different chemicals and colour change under the UV at 254 and 366 nm.  Though the information, studies on the biological and chemical activities of T. africanum is very scanty, the result in this study will further help in identifying the purity, correct identification of the crude drug, the standardisation and control of T. africanum (Tables 2 and 3).

FIGURE 1: UNISERIATE TRICHOMES AND ANISOCYTIC TYPE OF STOMATA FOUND IN TELOSMA AFRICANUM LEAF

FIGURE 2: TRANSVERSE SECTION OF TELOSMA AFRICANUM LEAF

Co – Collenchyma cells; Ep – Epidermal cells; xy - xylem

TABLE 2: FLUORESCENCE ANALYSIS OF T. AFRICANUM LEAF POWDER

TABLE 3: FLUORESCENCE ANALYSIS OF T. AFRICANUM STEM POWDER

The Phytochemical screening revealed the presence of combined Anthraquinone, Saponin, cardiac glycoside, alkaloids in the leaf and stem of T. africanum however, the stem lacked Flavonoid while they both lacked free Anthraquinone (Table 4).

In addition, the phytochemical results will give clues to the possible medicinal potentials and pharmacological properties of T. africanum.

TABLE 4:  PHYTOCHEMICAL SCREENING OF LEAF AND STEM OF T. AFRICANUM

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