Synergistic Interactions Between Medicinal Plant Bioactive and Standard Chemotherapy in Gastric Cancer: Preclinical Evidence and Translational Pitfalls

Abstract

Gastric cancer remains a highly heterogeneous malignancy in which chemotherapy response is limited by intrinsic and acquired resistance, cumulative toxicity, and the restricted predictive value of conventional preclinical models. This review critically synthesizes evidence on selected medicinal plants and their bioactive phytocompounds as adjuncts to standard chemotherapy for gastric cancer, with an emphasis on mechanistic plausibility, preclinical synergy, and translational barriers. Across the reviewed literature, phytocompounds from Curcuma longa, Scutellaria baicalensis, Camellia sinensis, Syzygium aromaticum, Glycyrrhiza glabra, Allium sativum, Marsdenia tenacissima, and Rhus verniciflua showed anticancer or chemopreventive activity through multitarget effects on apoptosis, proliferation, invasion, inflammation, oxidative stress, and resistance-associated signaling. The most convincing chemosensitizing evidence involved curcumin, wogonin, baicalein, EGCG, which enhanced the activity of fluoropyrimidines, platinum agents, paclitaxel, doxorubicin, or related antitumor regimens in selected gastric cancer models. However, the evidence base remains heterogeneous and is constrained by variable extract standardization, incomplete dose reporting, poor bioavailability, insufficient pharmacokinetic/pharmacodynamic integration, and underuse of clinically relevant model systems. Overall, medicinal plant bioactives remain promising adjunct candidates in gastric cancer. Still, meaningful translation will require chemically defined interventions, rigorous synergy analysis, interaction-aware study design, and validation in advanced preclinical and clinical settings.