Nigella sativa, or black cumin, is used as a spice in cooking and as a food supplement like seeds or oil for its biological properties, including antioxidant capacity, anti-inflammatory action, and support for the immune system. In the present study, the chemical composition and biological activities of the Nigella sativa seeds’ fatty oil (NS) were investigated. The analytical composition was carried out by several techniques, such as GC-MS spectrometry and ¹H- and ¹³C-NMR spectroscopies using appropriate internal standards. The GC-MS analysis highlighted the presence of palmitic and linoleic acid as major compounds. The antioxidant potential was evaluated through the DPPH radical-scavenging assay, and, furthermore, the NS effect on intracellular reactive oxygen species (ROS) levels was assessed in HaCaT cells (non-tumorigenic human keratinocytes) under oxidative stress induced by hydrogen peroxide. The cytotoxic and genotoxic profiles were evaluated on Caco-2 cells (human colorectal adenocarcinoma cells) using the CCK-8 viability assay and the Comet assay, respectively. Overall, the results demonstrated that NS possessed antioxidant activity, as evidenced by concentration-dependent DPPH radical scavenging and reduced intracellular ROS levels in HaCaT cells under oxidative stress. In Caco-2 colorectal cancer cells, NS induced significant cytotoxicity and DNA damage at higher concentrations, suggesting potential genotoxic effects. These findings support the dual role of NS as a natural antioxidant and a promising candidate for nutraceutical and dermatological applications, including those targeting oxidative stress-related conditions and cancer.

Embryonic stem cells (ESCs) present a characteristic pluripotency heterogeneity correspondent to specific metastates. We recently demonstrated that retinoic acid (RA) induces an increase in a specific 2C-like metastate marked by target genes specific to the two-cell embryo stage in preimplantation. Prame (Preferentially expressed antigen in melanoma) is one of the principal actors of the pluripotency stage with a specific role in RA responsiveness. Additionally, PRAME is overexpressed in a variety of cancers, but its molecular functions are poorly understood. To further investigate Prame’s downstream targets, we used a chromatin immunoprecipitation sequencing (ChIP-seq) assay in RA-enriched 2C-like metastates and identified two specific target genes, Cdk8 and Cdkn2d, bound by Prame. These two targets, involved in cancer dedifferentiation and pluripotency, have been further validated in RA-resistant ESCs. Here, we observed for the first time that Prame controls the Cdk8 and Cdkn2d genes in ESCs after RA treatment, shedding light on the regulatory network behind the establishment of naïve pluripotency.

The genus Orthosiphon Benth., is a relatively small genus of the Lamiaceae family that includes forty-four accepted species distributed mainly in tropical and sub-tropical areas of Asia, Southern Africa, and Madagascar. The species usually occurs in woodland, grassland, or forest margins. Due to their curative properties, species of this genus have been largely utilized in the popular medicine of several countries. Essential oil from fresh post-flowering aerial parts of Orthosiphon schimperi Benth. (OS), a taxon not previously studied, was collected in Kenyan territory, and it was obtained by hydrodistillation (yield 0.15%); its chemical profile was investigated by GC–MS analysis, using a DB-5ms low-polarity GC column. Oxygenated monoterpenes dominated the OS composition, and eugenol methyl ether (79.5%) was, by far, the main constituent of the sample. Oxygenated sesquiterpenes were the second most abundant class (8.8%), mainly constituted by caryophyllene oxide (8.2%). The biological activity of OS was assessed by using cytotoxicity assays on HeLa cells (human cervical cancer cell line) and HaCaT cells (non-tumorigenic human keratinocytes). OS exhibited selective cytotoxicity toward HeLa cells (IC₅₀ = 29.44 µg/mL after 24 h of treatment), while having minimal or no impact on HaCaT cell viability. Western blot analysis indicates that, indeed, the EO induces selective apoptosis in HeLa cells, thereby suggesting a potential anticancer activity exhibited by O. schimperi EO.