Commonly known as marijuana or hemp, Cannabis sativa L. (Cannabaceae), contains numerous active compounds, particularly cannabinoids, which have been extensively studied for their biological activities. Among these, cannabidiol (CBD) stands out for its therapeutic potential, especially given its non-psychotropic effects. This review evaluates the antitumor properties of CBD, highlighting its various mechanisms of action, including the induction of apoptosis, autophagy, and necrosis. By synthesizing findings from in vitro studies on the cell death mechanisms and signaling pathways activated by CBD in various human tumor cell lines, this literature review emphasizes the therapeutic promise of this natural antineoplastic agent. We conducted a comprehensive search of articles in PubMed, Scopus, Springer, Medline, Lilacs, and Scielo databases from 1984 to February 2022. Of the forty-three articles included, the majority (68.18%) reported that CBD activates apoptosis, while 18.18% observed simultaneous apoptosis and autophagy, 9.09% focused on autophagy alone, and 4.54% indicated necrosis. The antitumor effects of CBD appear to be mediated by transient receptor potential cation channels (TRPVs) in endometrial cancer, glioma, bladder cancer, and myeloma, with TRPV1, TRPV2, and TRPV4 playing key roles in activating apoptosis. This knowledge paves the way for innovative therapeutic strategies that may enhance cancer treatment outcomes while minimizing the toxicity and side effects associated with conventional therapies.

Glioblastoma is the most prevalent and malignant brain tumor identified in adults. Surgical resection followed by radiotherapy and chemotherapy, mainly with temozolomide (TMZ), is the chosen treatment for this type of tumor. However, the average survival of patients is around 15 months. Novel approaches to glioblastoma treatment are greatly needed. Here, we aimed to investigate the anti-glioblastoma effect of the combination of matteucinol (Mat) (dihydroxyflavanone derived from Miconia chamissois Naudin) with the chemotherapeutic TMZ in vitro using tumor (U-251MG) and normal astrocyte (NHA) cell lines and in vivo using the chick embryo chorioallantoic membrane (CAM) assay. The combination was cytotoxic and selective for tumor cells (28 μg/mL Mat and 9.71 μg/mL TMZ). Additionally, the combination did not alter cell adhesion but caused morphological changes characteristic of apoptosis in vitro. Notably, the combination was also able to reduce tumor growth in the chick embryo model (CAM assay). The docking results showed that Mat was the best ligand to the cell death membrane receptor TNFR1 and to TNFR1/TMZ complex, suggesting that these two molecules may be working together increasing their potential. In conclusion, Mat-TMZ can be a good candidate for pharmacokinetic studies in view of clinical use for the treatment of glioblastoma.

Celtis iguanaea, widely used in Brazilian folk medicine, is known for its analgesic and anti-inflammatory properties. This study evaluated the in vitro antioxidant capacity and the in vivo antinociceptive and anti-inflammatory mechanisms of the standardized spray-dried Celtis iguanaea hydroethanolic leaf extract (SDCi). Phytochemical analysis showed that SDCi contains 21.78 ± 0.82 mg/g polyphenols, 49.69 ± 0.57 mg/g flavonoids, and 518.81 ± 18.02 mg/g phytosterols. UFLC-DAD-MS identified iridoid glycosides, p-coumaric acid glycosides, flavones, and unsaturated fatty acids. Antioxidant assays revealed an IC₅₀ of 301.6 ± 38.8 µg/mL for DPPH scavenging and an electrochemical index of 6.1 μA/V. In vivo, SDCi (100–1000 mg/kg, p.o) did not impair locomotor function (rotarod test) but significantly reduced acetic acid-induced abdominal writhing and both phases of the formalin test at higher doses (300 and 1000 mg/kg). The antinociceptive effects were independent of α-2 adrenergic receptors. SDCi also increased latency in the hot-plate test and reduced paw edema in the carrageenan model, accompanied by decreased IL-1β and increased IL-10 levels. Histological analysis showed a 50% reduction in inflammatory cell infiltration. These findings support SDCi as an effective anti-inflammatory and antinociceptive phytopharmaceutical intermediate, with potential applications in managing pain and inflammation.

Celtis iguanaea, widely used in Brazilian folk medicine, is known for its analgesic and anti-inflammatory properties. This study evaluated the in vitro antioxidant capacity and the in vivo antinociceptive and anti-inflammatory mechanisms of the standardized spray-dried C. iguanaea extract (SDCi). Phytochemical analysis showed that SDCi contains 21.78 ± 0.82 mg/g polyphenols, 49.69 ± 0.57 mg/g flavonoids, and 518.81 ± 18.02 mg/g phytosterols. UFLC-DAD-MS identified iridoid glycosides, p-coumaric acid glycosides, flavones, and unsaturated fatty acids. Antioxidant assays revealed an IC₅₀ of 301.6 ± 38.8 µg/mL for DPPH scavenging and an electrochemical index of 6.1 μA/V. In vivo, SDCi (100–1000 mg/kg, p.o.) did not impair locomotor function (rotarod test), but significantly reduced acetic acid-induced abdominal writhing and both phases of the formalin test at higher doses (300 and 1000 mg/kg). The antinociceptive effects were independent of α-2 adrenergic receptors. SDCi also increased latency in the hot-plate test and reduced paw edema in the carrageenan model, accompanied by decreased IL-1β and increased IL-10 levels. Histological analysis showed a 50% reduction in inflammatory cell infiltration. These findings support SDCi as an effective anti-inflammatory and antinociceptive phytopharmaceutical intermediate, with potential applications in managing pain and inflammation.

Head and neck squamous cell carcinoma (HNSCC) remains a challenge due to recurrence, metastasis, and resistance to conventional therapies, particularly in human papillomavirus (HPV)-negative tumors. Cannabidiol (CBD), a non-psychoactive phytocannabinoid, has demonstrated antitumor activity in several cancer models; however, its effects in chemoresistant HNSCC are not well established. This study evaluates the antitumor effects of CBD and cellular mechanisms in a cisplatin -resistant, HPV-negative HNSCC model. Cytotoxic effects of CBD were assessed in HN13 cells and compared with fibroblasts and keratinocytes using MTT and selectivity index analysis. Migration, invasion, metalloproteinase activity, clonogenic survival, and cytotoxicity on 3D spheroids were evaluated. Cell death-related mechanisms were investigated using acridine orange/propidium iodide staining and Western blot analysis of apoptosis, autophagy, and cell-cycle regulation. Antitumor activity and vascular safety were further assessed using the chorioallantoic membrane model and HET-CAM assay. The combined effect of CBD and CIS was evaluated using the combination index analysis. CBD exhibited selective cytotoxicity toward HN13 cells and reduced migration, invasion, matrix metalloproteinase-2/9 activity, clonogenic survival, and 3D spheroid growth. CBD altered proteins associated with apoptosis, autophagy, and cell-cycle regulation. Pharmacological inhibition with 3-MA enhanced CBD-associated apoptotic signaling, increasing PARP and caspase-3 cleavage. In the CAM, CBD reduced tumor growth and vascular area without inducing vascular irritation. Furthermore, CBD and CIS demonstrated synergistic cytotoxic effects in HN13 cells. CBD exerted selective antitumor effects on CIS-resistant HN13 HNSCC cells, affecting tumor-associated behaviors and modulating apoptosis and autophagy-related signaling, while acting synergistically with cisplatin. These findings support further preclinical investigation of CBD as a potential adjunct approach in HNSCC, particularly in chemoresistant settings. Graphical abstract