Phytochemical Profiles, Antiproliferative and Antioxidant Activities of Carissa Edulis (Forssk.) Vahl) and Pappea Capensis (L.) Extracts
Loading...
Date
2022
Authors
Muruthi, W. Carolyn
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Cancer mortality is a global concern. In Kenya, cancer is ranked third cause of death.
Incidence rates for breast and prostate cancers exceed those of other forms of cancer.
Reactive species are implicated in all aspect of cancer, that is, initiation, promotion
progreesion. With the increased changes in lifestyle and environmental pollutants; the
burden caused by cancer will continue to have an upward trajectory. The current
therapeutic approaches despite showing efficacy are characterized by several limitations
such as adverse effects, prohibitive costs and sturdy resistance. This drives the need to
explore alternative anticancer drugs. Several studies have evaluated anticancer and
antioxidant effects of diverse plant extracts. In addition, toxicity effect of herbal plants
has been evaluated using various assays including brine shrimp (Artemia salina) lethality
assay. C. edulis and P. capensis are used as traditional therapy among the African
communities to manage cancer and oxidative stress-related ailments. However, there is
limited research on the antiproliferative and antioxidant effects of these medicinal plants.
The current study, therefore, sought to evaluate the phytochemical profile,
antiproliferative, antioxidant and in vivo cytotoxicity activities of C. edulis and P.
capensis extracts. Samples were collected from Embu County, Kenya. Phytochemical
profiles were determined using Liquid Chromatography Mass Spectrophotometer (LCMS)
and Gas Chromatography Mass Spectrophotometer (GC-MS) analyses.
Antiproliferative activity of the plant extracts against breast cancer (HCC 1395), prostate
cancer (DU145) and Vero (normal) cell lines was determined using MTT assay. Effect of
the extracts on expression of apoptotic genes (p53, bax and HOXB13) was evaluated
using quantitative Real Time Polymerase Chain Reaction (qRTPCR). In vitro antioxidant
properties of the extracts were evaluated through ferric reduction, Iron chelating,
hydroxyl radical, and I, I-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging
activities. Activities of catalase, superoxide dismutase and glutathione reductases of the
extracts were further determined. Toxicity of the extracts against was determined using
the brine shrimp lethality test (BSLA). The results indicated that ethyl acetate extracts of
C. edulis and P. capensis had the highest activity against cancer cells with IC50 values of
2.12±0.02, and 6.57±0.03μg/ml on HCC 1395 and 2.92±0.17 and 5.00±0.17μg/ml on
DU145, respectively. Moreover, all the extracts exhibited relatively less cytotoxic
activities against Vero cell lines (IC50>20μg/ml). The extracts also exhibited selectivity
againt the cancer cells (SI>3). Further, mRNA expression of p53 in the treated HCC 1395
was increased by 7 and 3-fold, whereas by 3 and 2-fold in DU145 cells, upon treatment
with ethyl acetate extracts of C. edulis and P. capensis, respectively. Similarly, severalfold
increases were observed in the number of transcripts of Bax in HCC 1395 and
HOXB13 in DU145 cells. The extracts had antioxidant activities whereby IC50 values
were less than 50mg/ml, indicating strong scavenging activities. BSLA assay indicated
that the extracts were non-toxic (LC50≥1000μg/ml) and had low toxicity (LC50≥500-
1000μg/ml) effects against A. salina. Phytochemical analyses revealed presence of
compounds which are associated with antiproliferative and antioxidant activities
including flavonoids, phenolics, tocopherols and terpenoids. The findings provide a
scientific validation for the folklore use of C. edulis and P. capensis in management of
cancer and oxidative stress. Nevertheless, there is a need for further purification and
characterization of phytochemicals associated with anticancer and antioxidant activities.
In addition, further toxicity assays should be conducted to explore effects of extracts on
organs weight, body weight, haematological and biochemical parameters.
Description
A Thesis Submitted In Fulfillments of the Requirement for the Award of the Degree of Doctor of Philosophy (Medical Biochemistry) in the School of Pure and Applied Sciences of Kenyatta University, October, 2022.
Keywords
Phytochemical Profiles, Antiproliferative, Antioxidant Activities, Carissa Edulis (Forssk.) Vahl), Pappea Capensis (L.), Extracts