ABSTRACT
Cancer is a major public health burden and leading cause of death in both developed and developing countries. Despite advances in molecular diagnostic techniques, cancer still affects many people worldwide. This makes the search for new anticancer agents with low side effects valuable. Spondias mombin L. (Family- Anacardiaceae) grows in coastal areas and in the rain forest into a big tree of up to 15 – 22 m. This study focused on ethno-medicinal survey and documentation of plants with folkloric use as anticancer agent in South-Western Nigeria; and also authenticate the anticancer claim of Spondias mombin leaves.
Well-structured questionnaires were randomly administered to respondents knowledgeable in the use of anticancer plants randomly. Database of enumerated plants were generated and specimens deposited at the University of Benin Herbarium. The leaves of S. mombin were air-dried, pulverized and subjected to cold extraction using distilled water, diethyl ether, ethanol and n-hexane as solvents before freeze-drying. Prior to investigating the anticancer potencies, the plant sample was subjected to toxicity tests by investigating the expressions of inflammatory and apoptotic marker genes. Next, non-toxic, well-tolerated plant extracts were investigated for their anticancer potencies; both prophylactic and curative experimental design approaches were adopted. At the termination of experiments, blood samples were collected for hematology, and tissue samples were excised for histopathological evaluation. Expression patterns of angiogenetic, tumor suppressor, intercellular ion channel and antioxidant genes were evaluated in the same tissues using reverse-transcription polymerase chain reaction (RT-PCR) method. The plant extracts active compounds were identified and characterized by Gas Chromatography-Mass Spectrometry (GC-MS) technique and docking studies were done on the compounds identified.
The results of the anticancer survey gave a total of 126 plant species belonging to 119 families. There was no sign of toxicity in any of the animals exposed to Spondias mombin leaves. The plant sample was able to downregulate the expression of toxicity biomarkers by blockade of inflammations in all the tissues studied. Spondias mombin leaves demonstrated cancer preventive activity in all the tissues by creating equilibrium between cell proliferation and apoptosis thereby blocking the putative mechanism of cell survival genes that can mediate tumorigenesis. The result of heamatological parameters showed that the hemoglobin content, red blood cell and white blood cell counts of all the treated groups were near to normal control group. Normal histological features were observed in control group animals, the negative groups showed the manifestations of cancer, all the treatment groups showed significant levels of repair almost similar to normal features in control group particularly in intestines and lungs. Spondias mombin extracts demonstrated their curative activities by downregulating the expressions of proangiogenetic genes and also restored the reactive oxygen species (ROS) rich cells of the tissues. The GC-MS analysis revealed 33 and 27 compounds of S. mombin n-Hexane and ethanol extracts respectively. The docking result showed that Lup-20(29)-en-3-one inhibited epidermal growth factor receptor (EGFR) with higher affinity than the standard drug (LBH589). In conclusion, the present data provided substantial evidence that S. mombin suppressed tumor growth in experimental animals and suggested thatextracts are potential chemopreventive and anticarcinogenic agents inhibiting chemically induced lung and intestinal cancers.
