Thesis Abstract

Abstract
Plants have been utilized for centuries in the treatment of various diseases caused by micro-organisms. This research aims to explore the role of plants in the treatment of such diseases based on their natural products. The use of plant-based remedies for microbial infections is rooted in traditional medicine practices that have been passed down through generations. The diverse array of bioactive compounds present in plants has shown promising antimicrobial properties against a wide range of pathogens including bacteria, viruses, fungi, and parasites. This study investigates the potential of plant-derived natural products as effective treatments for microbial infections. Various extraction methods are employed to isolate bioactive compounds from plants, including maceration, distillation, and extraction using organic solvents. The bioactive compounds are then tested for their antimicrobial activity through in vitro studies to determine their efficacy against specific micro-organisms. Furthermore, this research explores the mechanisms of action of plant-derived compounds against micro-organisms. Studies have shown that these natural products can disrupt microbial cell membranes, inhibit essential enzymes, and interfere with microbial DNA replication, leading to the inhibition of microbial growth. The synergistic effects of combining different plant-derived compounds are also investigated to enhance their antimicrobial activity and combat microbial resistance. In addition, the safety and toxicity profiles of plant-derived natural products are evaluated to ensure their suitability for use as antimicrobial agents. Studies have shown that many plant-based remedies have low toxicity levels and minimal side effects, making them attractive alternatives to synthetic antimicrobials. Moreover, this research delves into the potential challenges and future directions of utilizing plant-based treatments for microbial infections. Challenges such as standardization of plant extracts, identification of active compounds, and formulation of plant-based medicines are addressed to facilitate their integration into modern healthcare systems. In conclusion, plants play a significant role in the treatment of diseases caused by micro-organisms through their natural products. The rich source of bioactive compounds present in plants offers a sustainable and effective approach to combat microbial infections. Further research and development in this field can lead to the discovery of novel plant-based therapies that can address the growing threat of antimicrobial resistance.

Thesis Overview

1.1 BACKGROUND OF STUDY1.1.1 PhyllantusThis is a genus of the family Euphorbiaceae. It was first identified in Central and Southern India in 18th century. It is called carry me seed, stone-breaker, wind breaker, gulf leaf flower or gala of wind, (Bharatiya 1992).There are over 300 genera with over 5,000 species in the Euphorbiaceae world wide. The Phyllantus is one of the genus that falls under this enormous family. Phyllantus has about 750-800 species, found in tropical and subtropical regions. Green medicine is safe and more dependable than the costly synthetic drugs, many of which have adverse side effects (Joseph and Raj, 2010). The use of medicinal plants by man for the treatment of diseases has been in practice for a very long time. Screening of compounds obtained from plants for their pharmacological activity has resulted in the isolation of innumerable therapeutic agents.Over 50% of all modern chemical drugs are of natural plant product origin and is essential in drug development programs of the pharmaceutical industry (Burton et. al 1983).1.1.2 Phyllantus amarus (P. amarus)P. amarus is an erect annual herb of not more than one and half feet tall and has small leaves and yellow flowers. It is a broad medicinal plant that has received world-wide recognition (Srividiya and Perival, 1995).In herbal medicine, P. amarus has reportedly been used to treat jaundice, diabetes, otitis, diarrhea, swelling, skin ulcer, gastrointestinal disturbances and blocks DNA polymerase in the case of hepatitis B virus during reproduction, (Oluwafemi, and Debiri, 2008).In Nigeria, it is called -Oyomokeisoamankedem” in Efik, -Iyin Olobe” in Yoruba and -Ebebenizo” in Bini (Etta, 2008). In traditional medicine, it is used for its hepatoprotective, anti-diabetic, antihypertensive, analgesic, anti-inflammatory and anti- microbial properties (Adeneye et al; 2006). The plant is also used in the treatment of stomach disorders, skin diseases and cold (Kokwaro, 1976; Iwu, 1993). It has anti-diarrhea effect (Odetola and Akojenu, 2000). Its anti-viral activity against hepatitis B virus has been established (Thyagarajan et al; 1988, Wang et al; 1995), anti- carcinogenic (Joy and Kuttan, 1998), anti mutagenic activities (Joy and Kuttan, 1998), antiplasmodial (Soh et al. 2009).Plants contain numerous constituents, some tend to possess some level of toxicity. Cases of this toxicity in plants have been reported (Santox et al; 1995, Shaw et al; 1997, Kaplowitz, 1997). P. amarus has been classified among plants with a low potential for toxicity, with an LD50 averaging 2000mg/kg 1day (Krithika and Verma, 2009).1.1.3 Phyllantus niruri (P. niruri)P. niruri is commonly called stone breaker, also known as -Chanca piedra”. It belongs to the family Euphorbiaceae. P. niruri is similar to P. amarus. It is a wide spread tropical plant commonly found in coastal areas that grows 40-70cm tall (Chukwuma, 2012).In Nigeria, it is called enyikwonwa and ngwu in Ibo, Oyokeso amanke edem in Efik, geeron- tsemtsaayee in Hausa, ehin olobe and yin-olobe in Yoruba (Chukwuma, 2012).Although P. niruri is considered a problematic weed to formers it is a valuable medicinal plant. (Oudhia and Tripathi, 2002), and holds a reputed position in both Ayurvedic and Unani system of medicine. Recently, it has attracted the attention of researchers, because of its hepatoprotective (ability to prevent damage to the liver) properties. No effective specific therapy is available for viral Hepatitis but P. niruri has shown clinical efficiency in viral Heptatis B (Paranjape, 2001).P. niruri is an annual plant, its stem is angular with numerous distichous, ellipticoblong leaves. Flowers are yellow and very numerous; monoecious with 1-3 staminate flowers and solitary pistillate flower borne axillary. Fruits capsule, very small, globose, smooth, seeds 3-gonous, longitudinally ribbed on the back. Seed to seed cycle occurs in two or four weeks (Caius 1986), (Agharkar 1991). Its root, leaves, fruits, milky juice and whole plants are used as medicine. According to Ayurvedic system of medicine it is considered acrid, cooling, aleixipharmic and useful in thirst, bronchitis, leprosy, anemia, urinary discharge, anuria, boiliousness, asthma, for hiccups, and as a diuretic. According to Unani system of medicine, it is stomachic and good for sores and useful in Chromic dysentery. Fruits useful for tubercular ulcers, wounds, sores, scabies and ring worm (Agharkar 1991, Krishanamurty 1993). The fresh root is believed to be an excellent remedy for jaundice.In many parts of India, it is commonly used for the treatment of snake bite. The active compounds phyllanthin and hypophyllanthim, nirtetralin and phyltetralin have been isolated from leaves, (Rastogi and Mehrotra, 1991). The plant is used as a fish poison. In many parts of India especially in deserts, the roots mixed with Commiphora mukul are given to camels to cure indigestion. The decoction of leaves and stem are used for dying cotton black, (Singh et al; 1996).P. niruri is one of the medicinal plants used to treat malaria in India and Nigeria. P. niruri has been used traditionally to treat various illnesses including renal stones, gastrointestinal disturbance, cough, hepatitis, gonorrhea, fever and malaria. It has also been reported to posses hypoglycemic activity (Hukuri, et al; 1988), angiotension converting enzyme inhibition (Ueno, et al; 1988), lipid lowering activity (Khanna, et al; 2002), anti HIV activity (Qian cutron, et al; 1996) and anti cancer activity (Giridharan, et al; 2002).1.2 Aim and objectivesThis study is aimed at showing which of the plants above is more effective in the treatment of diseases caused by micro-organisms based in the natural products present in them.The specific objectives include;a. Determination of antibacterial effect of P. amarus and P. niruri.b. Determination of anti fungal effect of P. amarus and P. niruri.