Napoleona vogelii is most commonly used in herbal preparations to cure wounds, burns, fever, pneumonia, syphilis and staphylococcal infections. This work was carried out to determine the antimicrobial effectiveness of the extract from Napoleona vogelii leaves on some bacterial strains. The leaves of Napoleona vogelii was collected from the Botanical garden of Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria, in the month of December, 2018 and air dried until constant weight of the sample was achieved. The sample was grounded into fine powder and cold extracted using methanol and sterile distilled water solution in the ratio 3:2 (v/v) for 4 days with regular agitation. The supernatant was filtered and concentrated in-vacuo using rotary evaporator to expel the methanol and the aqueous part was then lyophilized to obtain the crude extract. The antimicrobial activity of the crude extract was tested against some selected bacterial strains using agar-well diffusion method, of which it inhibited 14 bacterial pathogens out of 20. Streptomycin was used as positive control. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined using standard methods. The mean diameter of the zones of inhibition exhibited by the plant extract against the bacterial strains ranged between 13 mm to 17 mm, while the diameter of zones of inhibition exhibited by streptomycin ranged from 14 mm to 25 mm. The MIC value was between 1.09 mg/mL and 17.5 mg/mL while the MBC value ranged between 2.19 mg/mL and 17.5 mg/mL. The phytochemical screening of the plant extract showed the presence of tannins, saponins, flavoloids, alkaloids, terpenoids, cardiac glycosides, and carbohydrate. In conclusion, the extract obtained from Napoleona vogelii leaves exhibited appreciable antibacterial activity against the test pathogens and hence can serve as a remedy for bacterial infections.
Abstract
Napoleona vogelii is most commonly used in herbal preparations to cure wounds, burns, fever, pneumonia, syphilis and staphylococcal infections. This work was carried out to determine the antimicrobial effectiveness of the extract from Napoleona vogelii leaves on some bacterial strains. The leaves of Napoleona vogelii was collected from the Botanical garden of Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria, in the month of December, 2018 and air dried until constant weight of the sample was achieved. The sample was grounded into fine powder and cold extracted using methanol and sterile distilled water solution in the ratio 3:2 (v/v) for 4 days with regular agitation. The supernatant was filtered and concentrated in-vacuo using rotary evaporator to expel the methanol and the aqueous part was then lyophilized to obtain the crude extract. The antimicrobial activity of the crude extract was tested against some selected bacterial strains using agar-well diffusion method, of which it inhibited 14 bacterial pathogens out of 20. Streptomycin was used as positive control. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined using standard methods. The mean diameter of the zones of inhibition exhibited by the plant extract against the bacterial strains ranged between 13 mm to 17 mm, while the diameter of zones of inhibition exhibited by streptomycin ranged from 14 mm to 25 mm. The MIC value was between 1.09 mg/mL and 17.5 mg/mL while the MBC value ranged between 2.19 mg/mL and 17.5 mg/mL. The phytochemical screening of the plant extract showed the presence of tannins, saponins, flavoloids, alkaloids, terpenoids, cardiac glycosides, and carbohydrate. In conclusion, the extract obtained from Napoleona vogelii leaves exhibited appreciable antibacterial activity against the test pathogens and hence can serve as a remedy for bacterial infections.
Keywords Napoleona vogelii, Antimicrobial, Antibacterial, Bacterial Strains, Human Infections, MIC, MBC, Phytochemicals.
1. Introduction
Since the time immemorial, humans have used natural products, such as plants, animals, microorganisms, and marine organisms, in medicines to alleviate and treat diseases. According to fossil records, the use of plants as medicines by humans may be traced back at least 60,000 years[14] Most of the population of most developing countries regularly depends on traditional medicine. The traditional health care practice of indigenous people pertaining to human health is termed, “alternative medicine,” “complementary medicine or “Ethno medicine” which includes products processed or derived from living organisms, including plants, animals, insects, microorganisms, and marine organisms[10]. In some African, Asian, Latin American countries, more than half of the population relies on traditional medicine and different types of traditional medicines are widely applied across this countries, and to meet their primary health-care needs. Traditional medicine has maintained its popularity in most regions of the developing world [10].
The knowledge of herbs, animals and minerals that have curative and palliative effects were transmitted from one generation to another and it is the outcome of bold experimentation through trial and error method over hundreds of years [18]. The knowledge of traditional medicine is thought to be within the reach of everyone and does not require study or training to practice. Traditional medicine has maintained its popularity in most regions of the developing world [16]. Traditional medicine has been used in wound treatment, bone healing, poisonous bite, and neurological disorders [16]. If the material being used is of plant origin, then it is called traditional herbal medicine or phytomedicine, which has been regarded as the most popular form of traditional medicine [10]. Plant products play an important role in healthcare delivery as therapeutic remedies in the world, especially in developing countries. This has caused phytomedicine to become an integral part of the healthcare system of many nations [4].
The use of medicinal plants as to treat microbial invasion can be traced back to early civilizations in China, India and the Near East, thus making traditional herbal medicine doubtlessly one of mankind’s oldest professions [11]. Medicinal plants have been used for centuries as remedies for human diseases and have provided new sources of chemical compounds with biological activity as antimicrobial agents [5]. The biologically active components of plant extracts and essential oils are used in most of the pharmaceutical industries because of their antimicrobial, antifungal, and antiviral properties. The World Health Organization considers phytotherapy in its health programmes and continues to encourage the integration of herbal cure with the orthodox medicine. Infectious diseases caused by bacteria, fungi, and viruses are still in increase and they are still the major threat to public health [2].
Many works have been done which aim at knowing the different antimicrobial and phytochemical constituents of medicinal plants and using them for the treatment of microbial infections (both topical and systemic applications) as possible alternatives to chemically synthetic drugs to which many infectious microorganisms have become resistant [2]. World Health Organization (WHO) has pointed it out that medicinal plants could be the best source to obtain a variety of drugs [7]. Therefore, there has been a global resurgence in the use of herbal preparations in disease management in all continents of the World and most developing countries are now integrating traditional herbal medicine into their health care systems [6]. This work is one of such attempt.
Napoleona vogeliibelongs to the family Lecythidaceae. The common name in English is “Napoleona”, also called “Hook fruit” and local names are “Gbogbori” in Yoruba, “Mkpodu” in Igbo. It is an evergreen shrub or a low branching tree with a dense crown growing up to 15 metres tall[17].
Napoleona vogeliiis a sweet and edible fruit found in a holly- a tree with hard prickly leaves all through the year and the ripe fruits in the dry seasons [9]. It is found mostly in rain forests and along sea shores extending from Sierra Leone to Nigeria [17]. About 20 genera and 450 species have been identified in the tropical regions of Africa, Asia, Australia and it is distributed mostly in Africa countries of Nigeria, Ghana, Guinea, Togo and Benin [17]. Its medicinal uses are for curing diabetes, fever, cough and catarrh [1].
The methanol extract ofNapoleona vogeliiis used in the treatment of peptic ulcer disease [1]. The leaves are also used in the treatment of cough and asthma and are said to possess hypoglycaemic effect [1]. The methanol and n-hexane leaf extracts ofNapoleona Vogeliihave been investigated for anti-ulcer related properties using three experimental ulcer models induced by ethanol, indomethacin and hypothermic-restraint stress in rats [1].
The anti-ulcer related properties of theNapoleona vogeliiextract such as gastrointestinal transit, the activity on isolated gut tissue preparation and antimicrobial activities have also been determined. The extracts appear to exhibit better protection against indomethacin and ethanol induced ulcer than against the stress ulcer [1].
2. Materials and Methods
2.1 Drying and Extraction of Bioactive Components of the Plant Sample
FreshNapoleona vogeliileaves were collected from the Botanical garden of Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria, in the month of December, 2018. The plant was authenticated in Herbarium of Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria by Mr Ogunlowo. The leaves were air-dried until a constant weight of the sample was obtained. The dried sample was ground into fine powder. Exactly 200 g of the powdered sample was soaked in methanol/sterile distilled water in ratio 3:2 (v/v) for 4 days on the laboratory bench with regular agitation. The supernatant collected was then filtered with glass wool into a sterile clean flask. The filtrate was concentratedin-vacuousing a rotary evaporator to remove the organic solvent. The aqueous part was then lyophilized leaving a brownish powdery crude extract. The extract was stored and kept in the refrigerator for further experiments.
2.2 Preparation of Microorganisms used for the Study
The Panel of standard bacterial strains from National Collection of Industrial Bacteria (NCIB) and locally isolated organism (LIO) used for the study were collected from culture collections of Prof. Akinpelu, at Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. The organisms were re-activated in nutrient broth and incubated at 37ºC for 18 h before use. The organisms were standardized before use.
2.3 Culture Media Employed
Nutrient agar and nutrient broth (LAB M Lancashire BL97JJ, UK) were used for sub culturing the organisms while Mueller-Hinton agar (LAB M Lancashire BL97JJ, UK) was used for sensitivity testing. The media were initially sterilized by autoclaving at 121oC for 15 minutes.
2.4 Antimicrobial Sensitivity Testing of Crude Leaf Extract of Napoleona vogelii on some selected Bacterial Strains.
The sensitivity testing of the extract was carried out using the agar-well diffusion method as described by [3]. The bacterial strains were grown in nutrient broth for 18 h for re-activation and standardized before use. The inoculum was then streaked onto an already sterilized Mueller-Hinton agar medium at 40oC. Wells were bored on the agar medium aseptically using a sterile 6 mm cork borer. The wells were filled up with the solutions of the crude extracts of predetermined concentration, the concentration of the crude extract used was 35 mg/mL. Streptomycin was used as positive control at a concentration of 1 mg/mL. Proper care was taken not to allow the solution of the extract to spill on the surface of the agar medium. The plates were then allowed to stand on the laboratory bench for an hour to facilitate diffusion of the extract solution into the medium and incubated at 37ºC for 24 h. The plates were later observed for zones of inhibition in which the relative susceptibility of the extract was indicated by clear zones of inhibition of growth around the wells and were examined and measured in millimetre using transparent rulers. The effects of the extract on bacterial strains were compared with the standard antibiotic, Streptomycin.
2.5 Determination of The Minimum Inhibitory Concentrations (MICs) of Leaf Extract of Napoleona vogelii on Susceptible Bacterial Strains.
The MICs of the extract was determined by preparing two-fold dilution as described by [3]. Two-fold dilution of the extract was prepared and 2 mL of different concentrations of the solution was added to 18 mL of pre-sterilized molten nutrient agar to give final concentration range of 0.274 mg/mL to 17.5 mg/mL. The medium was then poured into sterile Petri dishes and allowed to set and left on the laboratory bench overnight to ascertain that there were no contaminants in the prepared plates. The surfaces of the media were allowed to dry and streaked with an 18 h standardized inoculum of the susceptible bacterial strains. The plates were later incubated aerobically at 37ºC for 48 h after which they were examined for the presence or absence of bacterial growth. The MIC was taken as the lowest concentration that inhibited the growth of the bacterial strains.
2.5 Determination of The Minimum Bactericidal Concentrations (MBCs) of Leaf Extracts of Napoleona vogelii on Susceptible Bacterial Strains.
Minimum bactericidal concentrations of the extracts were determined against the susceptible bacterial strains according to [12].Samples for the MBC were taken from the line of streak on MIC plates without visible growth and then streaked on a freshly prepared extract free nutrient agar medium plates and incubated at 37ºC for 72 h. The plates were later examined for the presence or absence of growth. The MBC was taken as the lowest concentration of the extract that did not show any bacterial growth on the surface of the agar plates.
2.6 Determination of Phytochemical Compounds in the Plant Extract
A small portion of the dry extract was subjected to phytochemical test using method described by [15] and [8] methods to test for alkaloids, tannins, flavonoids, saponins, terpenoids, and cardiac glycoside.
3. Results
3.1 The crude extract obtained from leaves of Napoleona vogelii.
The crude extract obtained from 200 g of powdered leaves ofNapoleona vogeliiwas dark brown in colour. The yield was 18.5 g which was 12.3% of the powdered sample.
3.2 The antimicrobial sensitivity testing of leaf extract from Napoleona vogelii against the selected bacterial strains:
Table 1 shows the results exhibited by the leaves extract ofNapoleona vogeliiagainst the bacterial strains. The extract was found to be active against fifteen out of the twenty organisms tested at a concentration of 35 mg/mL. The zones of inhibition exhibited by the extract against the test organisms ranged between 13 mm to 17 mm.
Table 1: Antimicrobial sensitivity testing exhibited byNapoleona vogeliileaf extract against selected bacterial strains
Abbildung in dieser Leseprobe nicht enthalten
Keys:M/W: Methanol Water, 0 = Resistant, NCIB = National Collection of Industrial Bacteria,
LIO = Locally Isolated Organism. mm* = mean of three replicate readings.
3.3 The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) exhibited by Napoleona vogelii leaf extract against susceptible test bacterial strains:
The minimum inhibitory concentrations and minimum bactericidal concentrations of the leaf extract ofNapoleona vogeliiagainst susceptible bacterial strains were determined (Table 2). The MIC exhibited by the extract ranged between 1.09 mg/mL to 8.75 mg/mL, while, minimum bactericidal concentration (MBC) ranged between 2.19 mg/mL to 17.5 mg/mL.
Table 2: Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) exhibited byNapoleona vogeliiextract against susceptible bacterial strains
Abbildung in dieser Leseprobe nicht enthalten
Keys: NCIB = National Collection of Industrial Bacteria, LIO = Locally Isolated Organism, MIC = Minimum Inhibitory Concentration, MBC = Minimum Bactericidal Concentration.
3.4 Phytochemical constituents of the leaves extract obtained from Napoleona vogelii.
The result of the phytochemical analysis based on the chemical examination of the leaf extract ofNapoleona vogeliiis as indicated in Table 3.
Table 3: Phytochemical compounds present in the leaf extract ofNapoleona vogelii.
Abbildung in dieser Leseprobe nicht enthalten
4. Discussion
The bioactive components of leave extracts ofNapoleona vogeliiwere investigated for their antibacterial activities against selected pathogens associated with human infections. This study revealed the antibacterial activity of the methanolic extract of the leaves ofNapoleona vogelii.The extract was tested against 20 bacterial isolates comprising of both Gram positive and Gram negative organisms. The result shows that the plant has antibacterial activity against 14 out the 20 organisms it was tested against the bacterial isolates at 35 mg/mL. These organisms are known to be pathogens in humans, thus justifies the use of the plant to treat ailments traditionally. The plant was active against both Gram positive and Gram negative organisms which indicates that the plant is a broad spectrum antimicrobial agent, thus leaf extract fromNapoleona vogeliimay serve as a source of potent antimicrobial agent of natural origin to combat the infections caused by the pathogens and can reduce or prevent death of patients. The zone of inhibition exhibited by the plant extract range from 13 mm to 17 mm, streptomycin was used as positive control and the range of its inhibition was 14 mm to 25 mm, water was used as negative control and it inhibited none of the organisms.
The phytochemical screening of the plant extract revealed the presence of tannins, saponins, alkaloids, flavonoids, terpenoids, phenols, resin, sterols, carbohydrates, and glycosides which are known to contribute to the biological activities of medicinal plants, these phytochemicals thus contribute to the antibacterial activities ofNapoleona vogelii. Studies have been revealed in previous studies that tannins have astringent properties: hasten the healing of wounds and mucous membrane [13]. Studies have also shown that saponins also exhibit cytotoxic effect and the growth inhibition against a variety of cell making them have anti-inflammatory anti-cancer properties. They also show tumour inhibiting activity in animals. The presence of these phytochemicals contributed to the usefulness ofNapoleona vogeliiin folklore remedies. Flavonoids, one of the phytochemicals detected inNapoleona vogeliiextract used in this study are known to possess anti-inflammatory, anti-allergic, anti-mutagenic and antiviral activities.
Drugs manufactured fromNapoleona vogeliicould serve as remedy in the treatment and control of infectious diseases caused by the bacterial strains that were susceptible to this plant extract in our findings.
5. Conclusion
In conclusion, plants have been used for medicinal purpose as far back as the disease itself. This research established the possibility of developing a novel drug fromNapoleona vogeliileaf extract for a safe and effective antimicrobial agent for combating bacterial infection which has continued to be of immense economic and health importance in many countries. Abbildung in dieser Leseprobe nicht enthalten
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- Sulaimon Araromi (Author), 2022, Leaf extract of "Napoleona vogelli" on bacterial strains associated with human infections, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/1235841
