Anticancer Activity of Moringa peregrina (Forssk.) Fiori.: A Native Plant in Traditional Herbal Medicine of the United Arab Emirates

Moringa peregrina (Forssk.) Fiori. is a native desert tree growing in United Arab Emirates (UAE). The plant is being cultivated in many parts of UAE, owing to its uses in traditional medicinal and food systems. In the present study bioactivities of cultivated M. peregrina species samples are evaluated with cytotoxic studies in the human breast cancer cell line (MCF-7) and human colon adenocarcinoma cell line (Caco-2). Different extracts with hexane, chloroform, acetone and methanol were prepared from tubers, leaves and stem of M. peregrina for estimating their antioxidant contents and anticancer activities. The study was performed at different concentrations and all the extracts showed dose-depended response on both the cell lines. Among the extracts tested, the chloroform extract of stem showed remarkable anti-proliferative/cell death activity (IC50 = 45.53 µg/mL of 48 h incubation and 33.32 µg/mL of 72 h incubation) on MCF-7 cell lines. Whereas the same extract showed comparatively less activity (IC50 = 93.75 µg/mL of 48 h incubation and 87.76 µg/mL of 72 h incubation) on Caco-2 cell lines. The anti-proliferative effect of leaf extract with chloroform showed a drastic change in cell viability from 48 to 72 h incubation, in MCF-7 cells 220 to 87.5 µg/mL and in Caco-2 cells 500.9 to 72.9 µg/mL, respectively. Moreover, less than 200 µg/mL of IC50 values reported in hexane extracts of tubers (188.6 µg/mL for 48 h and 164.3 µg/mL for 72 h), acetone extracts of tubers (167.4 µg/mL for 72 h) and acetone extracts of stem (171.5 µg/mL for 48 h and 101.7 µg/mL for 72 h) on MCF-7 cells. PARP (Poly (ADP-ribose) polymerase) cleavage assay and DNA fragmentation assay performed to understand the cause of cell death. Treatment of extract on the normal fibroblast cell line required more concentration for cytotoxicity compared to the treatment on the cancer cells. This ability of the extract proved the anti-cancer property of the M. peregrina extract from the stem, tuber and leaves. The information provided in the present study enables further studies on the isolation and characterization of an anticancer molecule from the tubers of M. peregrina.

Cambial Activity of Moringa peregrina (Forssk.) Fiori in Arid Environments

Moringa peregrina (Forssk.) Fiori, one of 13 species of the Moringaceae family widely distributed throughout the dry tropics, has the potential to become one of the most economically important medicinal plants in Egypt. However, despite its tolerance for drought and heat, it is also threatened by increasing temperatures and decreasing precipitation. Although the phenophase of this species is well documented, almost nothing is known about its period of cambial activity in desert regions. Ring formation and the general environmental adaptability of trees are affected by the timing of cambial activation. In our study site, we observe a distinct coupling of the development of new green leaves at the onset of vegetative growth in October and the phase of cambial activity (November–January). The onset of cambial activity seems to be related to a drop in temperature in October and the onset of torrential rains in the region. There might even be a short phase between the end of cambial activity and the onset of bud formation without xylem formation, but with photosynthetic activity. If so, we assume that all assimilates are stored as non-structural carbohydrates (NSC) in the parenchyma of the new ring. This potential gap opens new questions regarding the correlation between NSC storage capacity and the timing of remobilization for subsequent ring formation.

Floral and Pollen Traits of Moringa oleifera Lam. and Moringa peregrina (Forssk.) Fiori Provide Reproductive Adaptations for Arid Conditions

Our study attempted to elucidate the significance of floral and pollen traits of the highly nutritious tropical trees Moringa oleifera and Moringa peregrina for their reproductive success under arid conditions. We found that the pollen grains of both species were immersed in a pollenkitt that constituted ~ 60% of the pollen. Successful pollination was achieved by large bees inserting the pollen into a narrow stylar tube. We found that, upon removal of the pollenkitt, approximately 65% fewer pollen grains penetrated the stylar tube for both species. The pollenkitt protected against heat and desiccation, while removing the pollenkitt resulted in significantly reduced levels of the viability of pollen grains, especially in M. oleifera, and significantly reduced levels of germinability in both species. The stylar tube provided high protection for pollen grains against heat and desiccation even when the pollenkitt was removed. Chemical analysis of pollenkitts of the two species revealed a waxy blend of 21 hydrocarbon compounds, in which n-alkanes constituted > 90% of the compounds and their identity corresponded to known plant and animal hydrocarbons, associated with protection against heat and water stress. We concluded that, under arid conditions, the reproductive success of both Moringa species is potentially enhanced by their unique floral and pollen traits. This supports the prospect of cultivating M. oleifera and Moringa peregrina as food crops in arid regions across the globe.