Abstract
Cancer is a group of diseases characterised by uncontrolled proliferation of cells. Of
all the types of cancers worldwide, breast cancer is the most commonly diagnosed in
women while prostate cancer is the second in men. The current cancer management
methods have challenges including unpleasant side effects, high cost and even not
effective. As the number of patients is on the rise, physicians look forward with hope
to the discovery and development of safe, effective and less toxic anticancer drugs.
More than 67 % of prescribed anticancer drugs have been developed based on natural
products. The objective of this study was to evaluate anticancer activities of extracts
obtained from Fagaropsis angolensis, Hydnora abyssinica, Launaea cornuta,
Spermacoce princeae, Combretum tanaense, Uvariodendron anisatum, Marsidenia
schimperi and Prunus africana against breast and prostate cancer cells. Methanol and
water extracts from the seven plants were evaluated for anticancer activities using
methyl thiazole tetrazolium cell viability (MTT) assay and microtiter 96 well plates.
Breast cancer (HCC 1395 and 4T1) and prostate cancer (DU-145 and 22RV1) cell
lines were used in this study. The contols that were used in this study were
cyclophosphamide and fluorouracil for positive chemotherapeutic agent and African
green monkey kidney epithelia normal cell (vero) for for cancer cells. Enzyme linked
immunosorbent assay (ELISA) scanning multiwell spectrophotometer was used to
measure optical densities to calculate cell viability. Analysis of concentrations that
inhibited 50% of cell growth (IC50) was done using Prism Graphpad version 8.0.
Remarkable activities of extracts (IC50 < 50 μg/ml) were demonstrated by the
methanol extracts of C. tanaense root, U. anisatum root, H. abyssinica rhizome, M.
schimperi husks, M. schimperi leaves and F. angolensis stem bark. High selectivity
indices were revealed F. angolensis extrcats. Bioassay-guided isolation of these
extracts resulted to isolation of seven compounds. The active fractions were those F.
angolensis and C. tanaense extracts, dichloromethane and ethyl acetate fractions,
respectively, the two fractions exhibited anticancer activities with moderate (1 ≤ SI
≤3) to high (SI > 3) selectivity indices. The isolated compounds were coded as FC1,
FC2, FC3, CC1, CC2, UC1 and UC2. The FC1-3 compunds were active against cancer
cell lines, CC1-2 revealed moderate activities and UC1-2 were not active. FC1 revealed
high selectivity indices against the cancer cell lines. All extracts that demonstrated
remarkable anticancer activities revealed no toxic effects upon acute oral toxicity
studies on swiss mice. It was therefore established that plants that were selected on
the basis of ethnopharmacological approach had potential anticancer activities and
were also relatively safe. Moreover, the compounds that were isolated were
remarkably active and less toxic. This study therefore provided scientific basis for
validating the use of extracts from Fagaropsis angolensis stem bark and Hydnora
abyssinica rhizome in the management and treatment of breast and prostate cancers.
