In Vitro Antiproliferative Effects and Phytochemical Characterization of Carissa edulis ((Forssk) Vahl) and Pappea capensis (Eckyl and Zeyh) Extracts.

Cancer mortality is a global concern. The current therapeutic approaches despite showing efficacy are characterized by several limitations. Search for alternatives has led to the use of herbal plants including C. edulis and P. capensis. However, there is limited research on antiproliferative effects of these medicinal plants. The study sought to evaluate antiproliferative effects of the plants against human breast and prostate cancers using cell viability, and gene expression assays to determine modulation of apoptotic genes. Further, Liquid Chromatography Mass Spectrophotometer (LC-MS) and Gas Chromatography Mass Spectrophotometer (GC-MS) analyses were performed to confirm phytocompounds in the extracts. The results indicated that ethylacetate 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 ± 0.03 µg/ml on HCC 1395 and 2.92 ± 0.17 and 5.00 ± 0.17 µg/ml on DU145, respectively. Moreover, the plants extracts exhibited relatively less cytotoxic activities against Vero cell lines (IC50 > 20 µg/ml). The extracts also exhibit selectivity against 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 ethylacetate extracts of C. edulis and P. capensis, respectively. Similarly, several-fold increases were observed in the number of transcripts of Bax in HCC 1395 and HOXB13 in DU145 cells. Phytochemical analyses detected presence of phytocompounds including flavonoids, phenolics, tocopherols and terpenoids which are associated with anticancer activity. Findings from this study provide a scientific validation for the folklore use of these plants in management of cancer.

In vitro antioxidant activities of Carissa edulis ((Forssk) Vahl) and Pappea capensis (Eckyl. & Zeyh) extracts.

Herbal medications are gaining popularity due to their long history of use in traditional medicine. They serve as a reservoir for a diverse array of phytocompounds linked to amelioration of oxidative stress. Oxidative stress is a disturbance in the balance between generation and elimination of reactive species in human body. Moreover, reactive species are implicated in the onset and progression of chronic disorders. The current therapeutic approaches despite showing efficacy are characterized by several limitations such as adverse effects and prohibitive costs. This drives the need to explore alternatives that can inhibit, ameliorate or reverse conditions caused by oxidative stress. Several studies have evaluated antioxidant effects of diverse plant extracts. C. edulis and P. capensis are used as traditional therapy among the African communities to manage oxidative stress-related ailments. However, there is limited research on the antioxidant effects of these medicinal plants. The current study, therefore, sought to evaluate the antioxidant and phytochemical profile, of C. edulis and P. capensis extracts. Samples were collected from Embu County, Kenya. In vitro antioxidant properties of the extracts were evaluated through ferric reduction, Iron chelating, hydroxyl radical, and DPPH radical scavenging activities. Activities of catalase, superoxide dismutase and glutathione reductases of the extracts were further determined. Phytochemical profiles were determined using Liquid Chromatography Mass Spectrophotometer (LC-MS) and Gas Chromatography Mass Spectrophotometer (GC-MS) analyses. The extracts displayed concentration dependent antioxidant activities. Phytochemical analyses revealed presence compounds which are associated with 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 oxidative stress. Nevertheless, there is a need for further purification and characterization of phytochemicals associated with antioxidant activities.

Coexistence of honeybees with distinct mitochondrial haplotypes and hybridised nuclear genomes on the Comoros Islands.

The honeybee, Apis mellifera, is a globally distributed species that has spread both naturally and by humans across the globe resulting in many natural and secondary contact zones. The geographic isolation of honeybees is likely to contribute to genetic differentiation. Secondary contact has resulted in hybridization at the nuclear genome, but replacement of mitochondrial. Here, we used a mitochondrial marker and 19 microsatellite markers to test for the variations in the mitochondrial and nuclear genomes of honeybee populations on the Comoros islands. We used samples of 160 workers for mtDNA analysis and 288 workers from 16 colonies spread across the three islands for microsatellite analyses. Our results showed that the wild honeybee populations of the Comoros Islands consist of coexisting mitochondrial haplotypes. One belongs to the typical African A-lineage, and the other, the newly described L-lineage, is closely related to Apis koschevnikovi, a honeybee species native to Southeast Asia. The nuclear genomes show complete hybridization, high genetic diversity, and strong differentiation according to the island of origin. Based on our results, we hypothesise that the Asian honeybee could have been transported from Southeast Asia to Madagascar and Comoros via the human migrations that occurred 6000 years ago, and has hybridised with African honeybees at the nuclear genome, but maternal ancestry still can be traced using the mtDNA markers. We conclude that mtDNA plays a pivotal role in adaptation to the local environment, with both haplotypes of the honeybees of Comoros contributing significantly to the mito-nuclear coadaptation resulting in maintenance at almost equal frequency.