- Open Access funded by Asian-African Society for Mycobacteriology
- Under a Creative Commons license
Abstract
Aims
The
current study was designed to document medicinal plant species that are
traditionally used to treat tuberculosis (TB) by Ghanaian communities.
Methods
The
medicinal plants used against TB or its signs and symptoms were
selected using library and online published data searches. A guided
questionnaire interview was also conducted with a botanist involved in
plant collection at the Centre for Scientific Research into Plant
Medicine (CSRPM) at Mampong. Data obtained were entered in Excel and
summarized into means and frequencies using SPSS 12.0.1 for windows, and
expressed as tables and bar graphs.
Results
A
total of 15 medicinal plant species distributed between 13 genera and
13 families were documented. The following medicinal plant species were
found to be used against TB in Greater Accra and Eastern parts of Ghana:
Azadirachta indica A. Juss. Stem bark (Meliaceae), Hygrophila auriculata Heine, whole plant (Acanthaceae), Chenopodium ambrosioides L. leaves (Amaranthaceae), Coix lacryma-jobi L. glumes (Poaceae), Solanum torvum Sw. unripe fruits (Solanaceae), Solanum torvum Sw. leaves (Solanaceae), Bidens pilosa L. whole plant (Asteraceae), Phyllanthus fraternus G.L. Webster leaves (Phyllanthaceae), Dissotis rotundifolia (Sm.) Triana, leaves (Melastomataceae), Cymbopogon giganteus Chiov. Leaves (Poaceae), Cyperus articulatus L. roots (Cyperaceae), Allium sativum L. bulb (Amaryllidaceae), Zingiber officinale Roscoe, rhizomes (Zingiberaceae), Allium cepa L. bulbs (Amaryllidaceae), Allium cepa L. leaves (Amaryllidaceae), Aloe vera var. barbadensis aqueous extract from leaves (Xanthorrhoeaceae), Aloe vera var. barbadensis organic extract from leaves (Xanthorrhoeaceae), Cocos nucifera Linn, water (Arecaceae) and Cocos nucifera Linn. Husk (Arecaceae).
Conclusions
The
collected plant species could be a source of a new class of drugs
against TB. Bioactivity guided fractionation is recommended to identify
lead compounds for antimycobacterial activity. The current paper
documents for the first time medicinal plant species used by Ghanaian
communities to treat TB. These results are a basis for selection of
plants for further pharmacological, toxicological and phytochemical
studies in developing new plant-based antimycobacterial drugs.
Keywords
- Medicinal plants;
- Tuberculosis;
- Ghana
Introduction
Tuberculosis
(TB) is a major public health concern with over 2 billion people
currently infected, 8.6 million new cases per year, and more than
1.3 million deaths annually [1].
The current drug regimen combination for TB consists of isoniazid,
rifampicin, ethambutol and pyrazinamide, administered over six months [2] and [3].
Although this treatment has a high success rate, the utility of this
regimen is limited by compliance issues, which has resulted in the rise
of strains that are resistant to some or all of the first- and
second-line antibiotics [4]. These strains, called multidrug resistant (MDR), extensively drug resistant (XDR) and totally drug resistant (TDR) strains of Mycobacterium tuberculosis (M. tb), have worse disease outcomes [5]. Widespread introduction of antibiotics in the 1940s, beginning with penicillin [6], [7] and [8] and streptomycin [9]
transformed medicine, providing effective cures for the most prevalent
diseases of the time. Resistance development limits the useful lifespan
of antibiotics and results in the requirement of a constant introduction
of new compounds [10]. However, antimicrobial drug discovery is uniquely difficult [11],
primarily due to poor penetration of compounds into bacterial cells.
Recent efforts in TB drug development have resulted in the discovery of
new therapeutics, including delamanid (previously known as OPC 67683)
and bedaquiline (previously known as TMC 207), which retain activity
against MDR and XDR M. tb strains. However, additional drugs
are urgently needed. Natural products and their plant-derived analogs
are often a source of drugs or drug templates with limited toxicity,
which has the potential to mitigate compliance issues during protracted
administration. Plant-based drugs have been used worldwide in
traditional medicines for the treatment of various diseases and Ghana is
no exception. Approximately 60% of the world’s population still relies
on medicinal plants for their primary healthcare. According to a survey
by the National Cancer Institute (NCI), United States of America (USA),
61% of the 877 small-molecule new chemical entities introduced as drugs
worldwide during the period 1981–2002 were inspired by natural product
research [12].
Plant species still serve as a rich source of many novel biologically
active compounds, yet very few plant species have been thoroughly
investigated for their medicinal properties [13], and thus, there is renewed interest in phytomedicine research.
TB is a huge public health problem in Ghana [14].
It is estimated that approximately 20,000 people contracted TB in Ghana
in 2011, of which around 22% were not detected and/or reported [13] and [14].
According to 2011 data from the World Health Organization (WHO), 14,962
cases of TB were reported, comprising an incidence of 79 cases per
100,000. Of these, 18 cases per 100,000 corresponded to co-infection
with Human Immunodeficiency Virus-Tuberculosis (HIV-TB) co-infection [15].
The Ghanaian population still suffers the problems typical of an
underdeveloped, tropical country, with clear and markedly high death
rates resulting from malnutrition, tropical infectious diseases, and low
vaccine coverage. In Ghana, it is estimated that around 70% of
healthcare is provided by traditional healers using medicinal plants.
There is an estimated one traditional healer for every 400 inhabitants,
and one physician with conventional medical training for every 6200 (in
Accra, the capital city) to 42,200 inhabitants in the rural areas [16].
To achieve global control of this epidemic, there is an urgent need for
new TB drugs which can: (1) shorten treatment duration; (2) target MDR
or XDR strains; (3) simplify treatment by reducing the daily pill
burden; (4) lower dosing frequency (for example, a once-weekly regimen);
and (5) be co-administered with HIV medications [17].
The current study was thus designed to document medicinal plant species
traditionally used by the Greater Accra and Eastern communities of
Ghana to treat TB.
Materials and methods
Library and online published data searches
A
library search was carried out on medicinal plant species used in
traditional medicine to treat TB. In particular, plants cited in the
book “African traditional medicine: a dictionary of plant use and
applications” [18]
and growing in Ghana were selected, verified if they already had been
identified at the Herbarium of the Centre for Scientific Research into
Plant Medicine (CSRPM), Mampong, and assigned a voucher number as a
specimen collection of the CSRPM, with the help of the CSRPM botanist
team, led by Mr. Ofori Lartey. Plant species were collected from the
Greater Accra and Eastern regions of Ghana as shown in Fig. 1.
- Fig. 1.Map of Ghana.Source:www.mapsofworld.com.
Guided questionnaire interview
A
guided questionnaire interview was also administered to the botanist at
CSRPM. The interview elicited information on plant species used in the
traditional treatment of TB. All species obtained from literature and
those mentioned during the interview were collected during July and
December 2014 and are indexed as MN (Mwanzia Nguta). The specimens were
identified by the staff of CSRPM and named according to the Flora of
West Tropical Africa in accordance with the international code for
botanical nomenclature. The specimens were deposited at the CSRPM. Data
obtained were entered in Excel and summarized into means and frequencies
using SPSS 12.0.1 for windows, and expressed as tables and bar graphs.
Ethical approval for this study was granted by the Scientific and
Technical Committee of Noguchi Memorial Institute for Medical Research
(STC-NMIMR), project identification number EC/060/08. Before
interviewing the botanist at CSRPM, the objectives of the study, method
and planned use of the information were explained, and permission to
conduct the interview was sought. Verbal consent was obtained in all
cases before the interview was carried out. Selected plants used against
TB were also checked if they were published elsewhere in Africa, apart
from the work of Neuwinger [18].
Information
on plant extraction procedures utilized by the Greater Accra and
Eastern communities of Ghana was also sought after from the online and
library search. The interview conducted with the botanist at CSRPM also
generated information in regard to the methods used traditionally to
extract the active constituents from the anti-TB medicinal plant
species.
