Background: Chrysopogon zizanioides (L.) Roberty (vetiver) is a perennial medicinal grass with deep aromatic roots traditionally used for several ailments. Its root essential oil (CZEO) is rich in phytochemicals with documented antimicrobial, anti-inflammatory, and antioxidant activities. Although its anticancer potential remains underexplored, the complex phytochemical profile of CZEO positions it as a promising multi-target therapy, particularly for colorectal (CRC) and lung cancers where resistance and pathway redundancy often limit conventional treatments. Therefore, this study aimed to investigate the phytochemical composition and antiproliferative activity of CZEO from Qatar against colorectal (HCT-116) and lung (A549) cancer cells and to elucidate its molecular targets and mechanisms of action in CRC and lung cancer using network pharmacology and in silico approaches. Methods: CZEO was extracted by steam distillation and characterized using GC–MS. In vitro proliferation assays with HCT-116 colorectal and A549 lung cancer cells were conducted using the Alamar Blue assay. The ten most abundant phytochemicals identified by GC–MS were assessed for drug-likeness and ADMET properties and further analyzed through network pharmacology, molecular docking, and molecular dynamics (MD) simulations to elucidate the molecular targets and mechanisms underlying CZEO’s anticancer activity. Results: GC-MS profiling identified 40 compounds, predominantly sesquiterpenoids (93%), including khusimol, β-eudesmol, α-vetivone, and rosifoliol. CZEO inhibited cancer cell viability in a dose-dependent manner, with IC₅₀ values of 62.95 ± 2.19 µg/mL for HCT-116 and 167.82 ± 6.51 µg/mL for A549 cells, demonstrating greater potency against colorectal cancer. CZEO did not affect the growth of normal human neonatal fibroblasts (HDFn), suggesting potential selectivity for cancerous cells. ADMET predictions indicated favorable pharmacokinetics and low toxicity of CZEO’s top 10 abundant compounds (TACs). Network pharmacology revealed 373 and 394 overlapping gene targets between TACs and lung and colorectal cancer, respectively. The overlapping genes were used to construct a protein–protein interaction (PPI) network to identify hub genes. STAT3 and AKT1 consistently emerged as common top-scoring hub genes in both cancers. Molecular docking of TACs showed strong binding affinities of rosifoliol and α-vetivone to AKT1 (−6.20 and −5.93 kcal/mol, respectively) and STAT3 (−5.19 and −5.09 kcal/mol, respectively), surpassing reference inhibitors. MD simulations confirmed stable ligand–protein interactions and structural stabilization, particularly with α-vetivone. Conclusions: CZEO from Qatar exhibits potent antiproliferative activity against colorectal and lung cancer cells, supported by a sesquiterpenoid-rich phytochemical profile. Integrative computational analyses highlight AKT1 and STAT3 as key molecular targets, with rosifoliol and α-vetivone emerging as promising lead compounds. These findings support CZEO as a natural, multi-target anticancer agent, warranting further mechanistic and in vitro and in vivo validation.

Plants grown in arid environments can produce distinct secondary metabolite profiles as adaptive stress responses. This study evaluated the antimicrobial, antioxidant, and antibiofilm activities of essential oils (EOs) from two Ocimum species cultivated in Qatar: Ocimum basilicum L. (OB-S, sweet basil) and Ocimum africanum Lour. (OA-L, lemon basil). GC-MS analysis revealed distinct chemotypes: OB-S was linalool-rich (31.53% linalool and 12.91% eucalyptol), while OA-L was citral-dominant (78.34% geranial/neral). OB-S exhibited superior biological activity, showing a lower minimum inhibitory concentration against Listeria monocytogenes (MIC = 5 mg/mL) than OA-L (MIC = 10 mg/mL). Consistent with its higher total phenolic content (999.06 ± 8.30 vs. 37.77 ± 3.25 µg GAE/g EO), OB-S demonstrated significantly greater antioxidant capacity (DPPH EC₅₀ of 162.69 ± 0.78 vs. 939.38 ± 0.68 µg/mL). Further evaluation of OB-S EO and its major constituents (linalool, eugenol, estragole, eucalyptol) against L. monocytogenes biofilms revealed that while the whole EO reduced biofilm viability at 2MIC, isolated phytocompounds were more potent. Eugenol achieved the greatest reduction (reaching up to 5 log CFU/cm²), suggesting that it may be a major contributor to OB-S EO’s antibiofilm activity. These findings highlight the distinct chemotypic and bioactive profiles of these Ocimum species cultivated under arid conditions while also demonstrating eugenol’s potential for food-safety applications as a natural food preservative.