CHAPTER ONE

1.0.             INTRODUCTION

The word dermatophyte is from the Greek word “derma” meaning skin and “phyton” meaning plant. Dermatophytes are commonly referred to as ringworm or tinea infections. The name ringworm was coined to describe the circular lesion produced by the dermatophytes on the skin or scalp. The term ‘tinea’ is derived from the Latin word meaning “worm” or “moth” (Coulibaly and Coralie, 2018) and the second part of the name identifies the part of the body infected, example ‘tinea faciei’ (ringworm of the face). Dermatophytes cause infections of the skin, hair, and nails, obtaining nutrients from keratinized material. The organisms colonize the keratin tissues causing inflammation as the host responds to metabolic by-products of the fungi. Colonies of dermatophytes are usually restricted to the nonliving cornified layer of the epidermis because of their inability to penetrate viable tissue of an immunocompetent host. The serum fungal inhibitory factors in the extravascular space prevent their penetration in the living tissues, also their inability to tolerate human body temperature at 37^oC and the antifungal activity of blood proteins. Occasionally the organisms do invade subcutaneous tissues, resulting in kerion development (Goldsmith and Fitzpatrick 2012).

Diseases caused by fungi known as mycoses can be classified clinically as superficial, deep, or systemic mycoses. Dermatophytes are the most important organisms causing superficial mycoses (Molina de Diego, 2011). Dermatophytes lesion take a ring shape with inflammatory edges and clear center of normal skin. The lesions are often roughly circular with raised border but may coalesce to form confluent areas of dry, scaling skin, inducing itching and scratching which in severe cases may ulcerate (Abdul and Al-Janabi, 2014). Fungal elements are always found in active state in the edges of lesion and that is why it is preferable to take scrapping sample for microscopic diagnosis from the edges of lesion and not from the clear zone. The ring shapes of the dermatophyte infections can also be used to differentiate it from other skin diseases such as psoriasis or lichen planus in which the inflammatory responses tend to be uniform over the lesion (Hainer, 2003).

Invasive fungal infections, especially those caused by the species Candida and Aspergillus, continue to rise in frequency, (Brown, et al., 2012) and, alarmingly, are associated with antifungal resistance (Fisher, etal., 2018), which makes the management of patients with such infections particularly challenging (Arendrup and Patterson, 2017; Chowdhury. etal., 2017). Except for infections due to inherently antifungal-resistant species, the majority of these infections are clinically treatable by three currently available antifungal drug classes: triazoles (fluconazole, itraconazole, voriconazole, posaconazole, isavuconazole), echinocandins (anidulafungin, caspofungin, micafungin), and polyenes (amphotericin B-deoxycholate with its lipid and liposomal formulations) (Pappas, et al., 2016, Patterson, et al., 2016). Paralleling the relatively recent introduction of new antifungal drug classes (Robbins, et al 2016) and the discovery of novel agents (McCarthy, et al., 2017), for the treatment of invasive fungal infections, the field of antifungal susceptibility testing (AFST) has progressed tremendously in the past several years (Ostrosky-Zeichner and Andes, 2017).

Medicinal plants are frequently used in traditional medicine to treat different diseases. The World Health Organization (WHO) estimated that 80% of the earth's inhabitants depend on traditional medicine for their primary health care needs, and most of this therapy involves the use of plant extracts or their active components. This helped in exploration of different medicinal plants to find the scientific basis of their traditional uses, (Jachak, 2007). Medicinal plants contain a number of medicinal properties, (Prasobh et al., 2016). One of such plant is Musaparadisiaca, from the family Musaceae, also known as plantain is a tropical plant that is native to India. It is extensively cultivated in the tropics and is a staple crop for over 70 million people of the sub-Saharan Africa. The plant is an evergreen plant with an aerial pseudostem, an underground rhizome and a height of 2 to 9metes (Ekunwe and Ajayi, 2010). The leaves are oblong, deep green and narrowed to the base (Iman and Akter 2011). The fruit are edible, contain about 220 calories and are traditionally used in the treatment of various ailments (Lakshmi et al., 2015). It has been reported to have pharmacological activities such as antifungal, antilithiatic, antioxidant, antibacterial, antidiabetic, antiulcer, antidiarrhoeal, hypocholesterolaemic, hepatoprotective, antisnakevenom, wound healing, hair growth promoting and antimenorrhagic activity.

1.1.      STATEMENT OF THE PROBLEM

Fungal infection is one of the most common cutaneous infections worldwide (Havlickova et al., 2008),posing a great public health problem to humans and animals (Ameen, 2010). Fungi are eukaryotes and despite the presence of a cell wall, fungi are more similar to mammalian cells on a cellular level than to bacteria, making the treatment of mycotic infections difficult. Antifungal therapy has been limited by toxicities and resistance. The commonly used antifungal drugs such as amphotericin B, has toxic effects. Other drugs like ketoconazole, fluconazole and clotrimazole are limited in their spectrum and their use may produce strain resistance. Additionally, fungi replicate more slowly than bacteria and are often difficult to quantify, particularly moulds, which complicate efficacy assessments (Busayo, 2020). Hence the need for novel agents from plants, with less toxicity, broad spectrum of activity and shorter duration of action (Varuna et al.,2010).

1.2. JUSTIFICATION OF THE STUDY

Even though pharmaceutical industries have produced a number of new antifungal agents in the past decades, resistance to these drugs by fungi has increased. the problem of antifungal resistance is growing and the outlook for the use of antifungal drugs in the future is still uncertain.  Therefore, actions must be taken to reduce this problem such as continuous studies to develop new drugs either synthetic or natural that will offer appropriate and efficient antifungal therapy to the patient (Karadi, et al., 2011). Hence, this study is one of those actions towards development of a new antifungal molecule, this study will reveal the antifungal activities of Musaparadisiaca leaves which will serve as a tool for pharmaceutical industries to produce new antifungal agent that will improve the quality of life of the patients suffering from infectious fungal diseases.

1.3.      AIM OF THE STUDY

To assess the susceptibility of dermatophytes to the methanol extracts of Musaparadisiaca leaf.

1.4       OBJECTIVES OF THE STUDY

The objectives of the study include to carry out:

1. Extraction on the Musa parqdisiaca leaf using methanol as solvent. 
2. Phytochemical screening on methanol extract of Musaparadisiaca leaf to detect the presence of bioactive compounds
3. Susceptibility test to determine the activity against the fungi
4. Minimum inhibitory concentration (MIC) on the methanol extract of Musaparadisiaca leaf against selected fungi isolates.

Minimum fungicidal concentration (MFC) to determine the degree of activity of the methanol extract of Musa paradisiaca leaf against selected fungi isolates.