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European Journal of Applied Sciences – Vol. 11, No. 1

Publication Date: January 25, 2023

DOI:10.14738/aivp.111.13693.

Rajat, J., Jefwa, J. M., & Mwafaida, J. M. (2023). Efficacy of Selected Medicinal Plants of Kaya Kauma and Kaya Tsolokero Against

Bacterial Diseases. European Journal of Applied Sciences, 11(1). 70-79.

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Services for Science and Education – United Kingdom

Efficacy of Selected Medicinal Plants of Kaya Kauma and Kaya

Tsolokero Against Bacterial Diseases

Jolly Rajat

Pwani University, P.O. Box 195-80108, Kilifi, Kenya

Joyce Mnyazi Jefwa

Pwani University, P.O. Box 195-80108, Kilifi, Kenya

Joseph Mghalu Mwafaida

Pwani University, P.O. Box 195-80108, Kilifi, Kenya

ABSTRACT

An ethnobotanical study was carried out in the sacred Kaya forests of Kauma and

Tsolokero in Kilifi County in Kenya. Ethnobotanical data on useful and medicinal

plants was collected. Communities living around these two forests basically depend

on the diversity of flora for their livelihoods. The local herbalists use indigenous

trees and shrubs to treat a variety of diseases. These skills have been passed down

through generations. In this study, a survey was carried out in twenty-six villages

around Kaya Kauma (18) and Kaya Tsolokero (8). The population was interviewed

for knowledge on medicinal plants. More emphasis was put on the Traditional

herbal practitioners (THPs) possess more information on herbal plants, their

preparation and prescription for ailments they reportedly treat. Preliminary

reports indicated that most commonly treated ailments were caused by bacteria,

fungi and viruses in that order. Based on this, eleven (11) medicinal plants

recommended for bacteria-related ailments were selected and tested in the

laboratory to validate their efficacy against Escherichia coli and Staphylococcus

aureus. Suspensions of S. aureus and E. coli were prepared form 24h fresh colonies

and diluted to x10-7 cfu/ml where 100μl of each were plated to dry on 9cm plates

filled with King B media. A protocol adopted from the THPs was used to prepare

medicinal plant formulations from the selected plants. The plant materials were

subjected to soaking, boiling or roasting as recommended and finally formulated in

SDW at 1:1 (Wt/Vol). About 40μl of the plant formulations diluted at x10-1, x10-2 and

x10-3 and SDW as control treatment were loaded on sterile paper plugs, allowed to

air dry in a laminar flow before placing them equi-distantly at 4 cm radius on the

inoculated King B media plates. More than (64%) of tested plants suppressed the

growth of either S. aureus or E. coli while 4 (>30%) suppressed both test bacteria.

In total, 91 medicinal plants were mentioned by communities in Kaya Kauma (48)

and Tsolokero (43). THPs from the two forest commonly treated ailments caused

by bacteria, fungi and viruses in that order. The bioassay tests in this study

validated the potency of more than 75% of the recommended medicinal plants that

treated bacterial infections. Concentrations used in the study were far below what

is recommended by THPs which raises concerns of possibilities of over

prescriptions. There is need therefore to regularize and standardize products from

this fast-growing industry.

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Rajat, J., Jefwa, J. M., & Mwafaida, J. M. (2023). Efficacy of Selected Medicinal Plants of Kaya Kauma and Kaya Tsolokero Against Bacterial Diseases.

European Journal of Applied Sciences, 11(1). 70-79.

URL: http://dx.doi.org/10.14738/aivp.111.13693

Keywords: Kaya Forest, Indigenous medicinal plants, THPs

INTRODUCTION

Plant resources are considered the most important components of human diet [6]. In Africa,

communities have used indigenous medicinal plants for millennia to survive and maintain good

health [1]. Herbal medicine has complex combinations and interactions of herbal formulations

from assorted plants have been used successfully in traditional medicine for thousands of years

[1]. . Herbal medicinal products are still widely used by communities living in the proximity of

the forests. Medicinal products used to treat malaria, skin diseases, wounds, stomach ache,

diarrhoea, blood pressure disorders, gonorrhoea, common colds and coughs, boils, and an array

of livestock diseases have been reported from these communities [27]. However, many of the

medicinal plants used by traditional herbal practitioners (THPs) have not been well

documented, despite several challenges that threaten the sustainability of this industry. The

crude formulations, prescriptions and administration remain unique with repeated claims and

self-confessions by users and THPs alike for cure of various ailments.

Traditionally, medicinal plant formulations have been administered through oral infusions or

decoctions, steaming, smoking, rubbing, massaging and through skin incisions (Orwa et al.,

2009; Oyedemi et al., 2013). Drinking concoctions comparatively take longer to get absorbed,

work internally and rebalance the digestive system (WHO, 2002). The modern herbal medicine

owes it to Anthony Cunningham who through the Indigenous Plant Use Forum (IPUF) of 1993

created interest in commercialization of herbal medicine in the USA. This was followed by

intense ethno pharmacological studies and documentation that were driven by J. Van Staden et.

al. in 1999.

It was noted in this study that communities that have settled around the Kaya forests draw

useful plant resources for their livelihoods and for medicinal purposes to treat a variety of

ailments [27]. The THPs possess knowledge on formulations and prescription of these herbal

formulations which have sustained healthy populations in the study area. Knowledge on herbal

medicine is getting recognized by scientists’ world over and so is the role played by THPs who

are the custodians of this cultural practise [17]. Indigenous knowledge on herbal medicine lays

the foundation for scientific breakthroughs and therapeutically concepts which have

accelerated drug discovery through reverse pharmacology [8].

In this paper some of the medicinal plants described by Rajat et al (2017) are revisited and their

phytochemical profiles discussed in line with the potency they display as a source of medicinal

products for residents in the two study sites. The bioassays used in this study lay a foundation

for further bio-prospecting opportunities for indigenous medicinal products from the sacred

Kaya forests of Kilifi.

MATERIALS AND METHODS

Study Area

Two Kaya Forests, Kaya Kauma and Kaya Tsolokero in Kilifi were surveyed to establish

knowledge and skills in utilizing medicinal plants. Kaya Kauma is situated between E

03°37.103’; S 39°44.266’ and E 03°37.821’; S 39°44.200’. It is 100 ha in size at an altitude of

120m above the sea level. This is a deciduous forest that slopes into Ndzovuni river in the North

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European Journal of Applied Sciences (EJAS) Vol. 11, Issue 1, January-2023

Services for Science and Education – United Kingdom

with severe degradations close to the villages). Kaya Tsolokero is located in Junju. It is an

evergreen forest with 10 ha of forested land. Kaya elders guided a perimeter walk to map the

two forests. A GPS marking was taken every 10m to establish the boundaries and the villages

adjacent to these two forests.

Survey

A questionnaire survey was carried in Twenty-six (26) villages around Kaya Kauma (18) and

Kaya Tsolokero (8). The population was interviewed for knowledge on medicinal plants where

more emphasis was put on the traditional herbal practitioners (THPs) who possess more

knowledge on herbal plants, their preparation and prescription for ailments they reportedly

treat. Preliminary results indicated that the most commonly treated ailments were caused by

bacteria, fungi and viruses in that respective order. Based on the output from the indigenous

medicinal practitioners, plant species that were mentioned to treat bacterial related ailments

were selected for laboratory analyses

Selection of Pathogen and Medicinal Plant Species

Escherichia coli and Staphylococus aureus were selected as representative common pathogenic

bacteria in this evaluation. Staphylococcus aureus causes minor skin infection, bacteria derma

abscesses, pneumonia, meningitis, heart valve infections, and bone infections (Oakley et al.,

2004). Similarly, Escherichia coli causes bloody diarrhoea, stomach upsets, anaemia, urinary

tract infections and subsequently kidney failure (Silvia et al, 2011). These two pathogens

presented most of the described disease symptoms mentioned by the THPs. Escherichia coli

accession number AP001918 and S. aureus accession number AP003367 were collected from

KEMRI-Welcome trust, Kilifi, for use in this study. Eleven (11) medicinal plants that were

reported to treat bacterial related ailments. were selected for bioassays. These include; Croton

pseudopulchellus (Mnyama wa nyika), Diospyros cornii (Mkulu), Flagellaria guineensis

(Mchewa), Flueggea virosa (Mkwamba), Psilotrichum scleranthus (Chibiriti), Mildbraedia

carpinifolia (Mfundiragambi) Premna chrysoclada (Mvumo), Senna occidentalis (Mtsalafu),

Vernonia homilantha (Mlazakoma) Zanthoxylum chalybeum (Mdungu).

Preparation of Infusions

Extraction protocols adopted from those used by the traditional herbal practitioners were used

to prepare infusions from the selected plant samples. Samples were either soaked or boiled in

sterile distilled water (SDW) at a ratio 1:1 (Wt/Vol). Infusions that required soaking were

extracted in SDW at 4oC overnight. Boiled samples were extracted in SDW at a ratio of 1:2

(Wt/Vol) and allowed to simmer under low flame untill the water ratio was reduced to 1:1

(Wt/Vol). Samples that required roasting to ash were prepared by burning 100 g of plant

samples in Maffol Furnace at 450°C. The ash was then dissolved in 100ml SDW to prepae the

infusion. All the prepared infusions (Table 46) were then filter-sterilized through in 0.2μm

millipore filters under sterile conditions. The sterilized solutions were then standardized and

tested against pathogenic Eschericha coli and Staphylococus aureus in invitro trials.

Bioassays

Nutrient Agar (NA) and MacConkey Agar media were sterilized at 121°C for 15 minutes and

introduced into Petri plates under sterile conditions. Penicillin (Ampiclox) at a concentration

of 25mg/ml was used as a positive control in this trial. E. coli and S. aureus were cultured on