(*) Summary,
Sickle cell disease (SCD) is one of the most neglected diseases of the
21st century with an important death rate in children living in the
third world, especially in Africa. Like malaria, SCD is also a major
public health problem and is the first genetic disease by the number of
affected people in tropical African regions. The biophysics of SCD
includes polymerization of unstable haemoglobin S (HbS) under hypoxic
conditions, red blood cells shape and membrane modification. This is
the molecular basis of symptoms of SCD, like anaemia, red blood cells
haemolysis, thrombosis or veins obstruction amongst others.
Some
agents were developed by rational drug design to inhibit the red blood
cells sickling process. Most of these agents, unfortunately, did not
show promising success in terms of clinical use. Conventional
treatments are expensive and unaffordable by the rural populations.
During
these last few years, the use of medicinal plants is explored as a
therapeutic approach that can relieve this disease. Indeed, the use of
medicinal plants seems to be a simple, inexpensive and appropriate
strategy for disease control in developing countries.
The
progress made recently in biophysics, biochemistry and cellular biology
of SCD has indicated that main targets in chemotherapy must include
inhibition of haemoglobin S polymerization and stabilization red blood
cells membrane. Tests such as Emmel test (polymerization test), Itano
test (HbS solubility test), red blood cell haemolysis test and membrane
osmotic fragility test are used to evaluate in vitro the effect of
medicinal plants extracts on erythrocyte shape modification,
haemoglobin S aggregation in low O2 pressure conditions and membrane
stability. The first plant that showed an antisickling activity was
Fagara Zanthoxyloides. Some other plants extracts have showed
antisickling activity.
The ethnobotanical investigations
carried out by our research team have revealed that 76 medicinal plant
species belonging to almost 33 different families are used by Congolese
traditional healers for the treatment of SCD in the Democratic Republic
of Congo. A preliminary screening for the in vitro antisickling
activity using Emmel test has indicated that the polar extracts of
about 65 plants possess a significant sickling suppressive rate in
hypoxic conditions. Bioguided extraction has indicated that
anthocyanins and organic acids extracts would be among the secondary
metabolites responsible of the antisickling activity. Four bioactive
molecules have already been isolated and three of them are patented
(http://www.google.com/patents/WO2011064710A1?cl=en).
On the
other hand, some of these plants are edible and can be experimented as
medicinal food (nutraceutical) in sickle cell disease patients. One of
these plants is Vigna unguiculata (known as Cowpea or Black-eyed
Pea). A phytomedicine “drepano alpha” made of three edible plants
is also now being tested.
(**) Biodata: Professor
Pius Mpiana Tshimankinda is the Vice Head of the Chemical Department in
Charge of Research at the Science Faculty of the University of
Kinshasa, in the Democratic Republic of Congo. He obtained his PhD in
Physical Chemistry in 2003, from Kinshasa University and has been
Visiting Professor of Biophysics in some Congolese Universities. His
association with the ICTP goes from 2009 until 2015.
Professor
Mpiana is a member of some scientific organizations, amongst which: the
French Society of Etnopharmacology, the Natural Products Research
Network of Eastern and Central Africa (NAPRECA). He is also a member of
some editorial boards, such as the International Journal of Biological
Chemistry, the International Journal of Pharmacology, and the Research
Journal of Medicinal Plants.
The prizes awarded to him are the
Diploma and Medal of Scientific Merit of the Democratic Republic of
Congo in the year 2010; the African Prize for Liberty and Development,
2009; the Diploma of Honor and Merit as Best Congolese Professor for
2008.
Some
patents to his credit are: World International property organization
WIPO, Patent No W02011/064710 A1 “ In vitro antisickling activity of
betulinic acid, oleanolic acid and their derivatives”. Most
relevant, is his book “ Biophysique medicale”, volume I,
first edition 2006 and second edition 2010, published by Resud Edition,
Kinshasa. He is the author of 78 research papers.
Interview: Dealing with Sickle Cell Disease
ICTP Senior Associate discusses his advances toward treating SCD
