Abstract

Anticancer phytochemical compounds have shown considerable promise in preclinical studies; however, parameters like low aqueous solubility, chemical instability, and dose-related adverse effects restrict their therapeutic translation. Conventional formulations provide some degree of improvement, although they still suffer from limited bioavailability, rapid metabolism, and unfavorable pharmacokinetics. Nanomaterials such as graphene derivatives, including graphene oxide (GO), reduced GO (rGO), and graphene quantum dots (GQDs), have been at the core of research in advanced drug delivery systems. According to our literature review, phytochemicals including apigenin, paclitaxel (PTX), berberine, camptothecin, curcumin, doxorubicin (DOX), gingerol, irinotecan, podophyllotoxin, quercetin (QUE), vincristine, vinblastine, and extracts such as Juniperus squamata and Moringa peregrina, among others, have been successfully loaded. Drug loading efficiency ranges from 24% to 100%, and encapsulation efficiency up to 95%. pH-sensitive release is common: DOX achieved 84%–85% release at pH 5 within 18–48 hours, while CUR-loaded rGO released 96% at pH 5.4 over 72 hours. In vivo, there was significant tumour volume suppression at doses ranging from 2 to 20 mg/kg and particle sizes typically between 10 and 150 nm. Combination formulations, such as PTX–apigenin and QUE–lurbinectedin, showed synergistic cytotoxicity, reducing cancer cell viability by 29%–96% across HeLa, MCF-7, A549, HGC-27, and CCF-STTG1 cells, while sparing normal cells. Hybrid systems, including Au/GO and rGO–GQD composites, enhanced photothermal and fluorescence imaging, enabling theranostic applications. Bioaccumulation and nanocarrier size for GO/rGO (≥100–150 nm) and GQDs (≥20 nm) markedly influence absorption, biodistribution, and clearance kinetics. From a toxicity standpoint, high-dose exposures (50 mg/kg, i.v., or i.p.) of nonfunctionalized GO or rGO induce oxidative stress, erythrocyte hemolysis, pro-inflammatory cytokine release (TNF-α, IL-6, IL-1β), hepatic vacuolation, and mild inflammatory infiltration in BALB/c and Wistar rats. In zebrafish embryo and larval models, neurodevelopmental abnormalities, pericardial edema, and delayed hatching are evident at concentrations above 50–100 μg/ml. GO nanosheets (5–100 μg/ml) triggered ocular toxicity in mice, while low-dose GO (0.01–1 mg/l) during pregnancy caused multigenerational neurobehavioral alterations. Intravenous administration to pregnant mice (up to 1.25 mg/kg) led to fetal resorption, stillbirths, and reduced birth weight. rGO nanosheets (~70 nm) at 6.25–12.5 mg/kg induced complete abortion in female mice, whereas 25 mg/kg caused maternal mortality. Functionalized nanosystems, such as polyethylene glycol-GO (60–90 nm) and chitosan-rGO (70–120 nm), exhibited markedly reduced systemic toxicity, improved hemocompatibility, and enhanced colloidal stability. GQDs (20–280 nm) showed dose- and size-dependent effects, including mild mutagenicity, cytotoxicity, oxidative stress, and neurobehavioral alterations at higher doses (10–40 mg/kg, p.o., 30 days). Functionalization with dodecyl amine or trimethylammonium chloride substantially reduced immunotoxicity and cytotoxic effects. Human clinical data (NCT03659864 and NCT07034248) suggest good tolerability, with no significant respiratory, cardiovascular, or systemic adverse effects observed. The device-related trial (NCT06368310) indicates biocompatibility and safe application in biosensor platforms, while the consumer product–related study (NCT04881877) shows acceptability for graphene-based materials. This review will serve as a basis for understanding the fabrication, functionalization, drug loading, release, uptake, and therapeutic evaluation of GO, rGO, and GQD nanosystems, supported by preclinical and clinical trials.

Key words: Controlled release, clinical trials, formulation development, phytochemical compounds, toxicology, targeted delivery systems