Search Results (4)

The ecology and diversity of flowering parasitic plants and their hosts are poorly investigated and usually ignored in Saudi Arabian plant communities. Therefore, this work aimed at assessing the ecology and diversity of parasitic plants and their hosts along an elevation gradient in the Al-Baha region (1300–2400 m.a.s.l.). Different quantitative vegetation parameters were applied to analyze the collected data. Eight parasitic plants from six genera and four families were identified along the gradient, with 67% of them being zoochorously dispersed species. They accounted for approximately 23.5% (8 out of 34) of those found throughout Saudi Arabia. Perennials, stem hemiparasites, and biregional taxa accounted for around 62.5% of the total parasites, whereas indigenous species accounted for 75%. The dominant family of parasitic species was Loranthaceae (50%), and Phragmanthera austroarabica A.G.Mill. & J.A.Nyberg was the most important species (IVI = 107.28). Orobanche cernua Loefl. and Loranthella deflersii (Tiegh.) S.Blanco & C.E.Wetzel were restricted to the dry zone (low elevation) only, while the other parasites were distributed across the surveyed region. Twenty-three host plants were identified throughout the study region. About 83% of them were phanerophytes and bioregional plants, with 91% being perennial species. The prevalent host plant family across all sites was Fabaceae, with Nicotina glauca Graham being the most important host species (IVI = 32.44%). P. austroarabica and Plicosepalus curviflorus Tiegh. preferred Vachellias as host plants, while Vachellia flava (Forssk.) Kyal. & Boatwr. was the heavily infected host by P. austroarabica. P. austroarabica had a broad spectrum of host range (13 host plants), while O. cernua had a very narrow host range (only Rumex nervosus Vahl). Individual parasite and host species were markedly more abundant in the wet zone than in the low-altitude dry zone. Further research is needed to fully understand such distinctive groups of plants and their negative and positive ecological consequences on plant biodiversity and natural ecosystems. Full article

The Plicosepalus genus includes hemiparasitic mistletoe and belongs to the Loranthaceae family, and it has several medicinal uses. In the present study, we sequenced the complete plastomes of two species, Plicosepalus acaciae and Plicosepalus curviflorus, and compared them with the plastomes of photosynthetic species (hemiparasites) and nonphotosynthetic species (holoparasites) in the order Santalales. The complete chloroplast genomes of P. acaciae and P. curviflorus are circular molecules with lengths of 120,181 bp and 121,086 bp, respectively, containing 106 and 108 genes and 63 protein-coding genes, including 25 tRNA and 4 rRNA genes for each species. We observed a reduction in the genome size of P. acaciae and P. curviflorus and the loss of certain genes, although this reduction was less than that in the hemiparasite and holoparasitic cp genomes of the Santalales order. Phylogenetic analysis supported the taxonomic state of P. acaciae and P. curviflorus as members of the family Loranthaceae and tribe Lorantheae; however, the taxonomic status of certain tribes of Loranthaceae must be reconsidered and the species that belong to it must be verified. Furthermore, available chloroplast genome data of parasitic plants could help to strengthen efforts in weed management and encourage biotechnology research to improve host resistance. Full article

This study presents a comparison between two mistletoe plants—P. acacia and P. curviflorus—regarding their total phenolic contents and antioxidant and anticancer activities. P. curviflorus exhibited a higher total phenolics content (340.62 ± 19.46 mg GAE/g extract), and demonstrated higher DPPH free radical scavenging activity (IC₅₀ = 48.28 ± 3.41µg/mL), stronger reducing power (1.43 ± 0.54 mMol Fe⁺²/g) for ferric ions, and a greater total antioxidant capacity (41.89 ± 3.15 mg GAE/g) compared to P. acacia. The cytotoxic effects of P. acacia and P. curviflorus methanol extracts were examined on lung (A549), prostate (PC-3), ovarian (A2780) and breast (MDA-MB-231) cancer cells. The highest anticancer potential for the two extracts was observed on PC-3 prostate cancer cells, where P. curviflorus exhibited more pronounced antiproliferative activity (IC₅₀ = 25.83 μg/mL) than P. acacia (IC₅₀ = 34.12 μg/mL). In addition, both of the tested extracts arrested the cell cycle at the Pre-G1 and G1 phases, and induced apoptosis. However, P. curviflorus extract possessed the highest apoptotic effect, mediated by the upregulation of p53, Bax, and caspase-3, 8 and 9, and the downregulation of Bcl-2 expression. In the pursuit to link the chemical diversity of P. curviflorus with the exhibited bioactivities, its metabolomic profiling was achieved by the LC-ESI-TOF-MS/MS technique. This permitted the tentative identification of several phenolics—chiefly flavonoid derivatives, beside some triterpenes and sterols—in the P. curviflorus extract. Furthermore, all of the metabolites in P. curviflorus and P. acacia were inspected for their binding modes towards both CDK-2 and EGFR proteins using molecular docking studies in an attempt to understand the superiority of P. curviflorus over P. acacia regarding their antiproliferative effect on PC-3 cancer cells. Docking studies supported our experimental results; with all of this taken together, P. curviflorus could be regarded as a potential prospect for the development of chemotherapeutics for prostate cancer. Full article

A facile, eco-friendly fluorescence approach based on the biogenic formation of zinc oxide nanoparticles using the biomass of Plicosepalus curviflorus shoots was developed. The suggested approach was employed to analyze three phenolic compounds (catechin, curviflorside, and curviflorin) isolated from the shoots of P. curviflorus. The surface morphology of the prepared ZnONPs was characterized by carrying out different microscopic and spectroscopic investigations. A significant UV-Vis absorption peak of ZnONPs was recognized at 345 nm and the FT-IR spectra of the isolated catechin, curviflorside, and curviflorin in the presence of sodium dodecyl sulfate (SDS) and ZnONPs were recorded at λem 470, 490, and 484 nm after excitation at λex 380, 420, and 410 nm. The suggested fluorescence method displayed linear concentration ranges of 10–120, 5–100, and 10–150 μg mL⁻¹ for the three isolated compounds, respectively. The shoot extract, isolated compounds, and ZnONPs were screened for antibacterial and anticancer effects against four different types of bacterial strains and HeLa cells, respectively. The ZnONPs exhibited the highest zone of inhibition against Escherichia coli and Staphylococcus aureus strains when compared with pure, isolated compounds and shoot extract. The anticancer potential of ZnONPs (64%) was stronger as compared to the 160 µg mL⁻¹ of shoot extract (49%), catechin (52%), curviflorside (54%), and curviflorin (58%) at 160 µg mL⁻¹. Moreover, all the samples were investigated for hemolysis activity and showed a potent anti-hemolytic effect. The developed analytical method showed excellent sensitivity and reliability for the concurrent analysis of the isolated bioactive markers. Full article