Immunomodulatory Potential of Vietnamese Ganoderma Species: A Comparative Study in a Cyclophosphamide-Induced Immunosuppressed Model

Background and objectives: Ganoderma species are widely used in traditional medicine for their immunomodulatory properties. However, systematic evaluations of indigenous Vietnamese taxa remain limited. This study aimed to screen the immunomodulatory activity of selected Ganoderma species from the Central Highlands of Vietnam. Methods: A total of 920 samples from the Central Highlands were morphologically and genetically identified, yielding 43 classified species. Ten representative species were selected for biological evaluation based on ethnomycological records. In vivo immunomodulatory activity was evaluated using a cyclophosphamide-induced immunosuppression mouse model, including normal control, pathological, and positive (filgrastim) control groups. Evaluated parameters included lymphoid organ indices and hematological profiles. In vitro cell viability was assessed using the MTT assay on human peripheral blood mononuclear cells (hPBMCs). Results: In vivo results indicated several extracts, particularly Ganoderma lucidum (LE 23) and Ganoderma sp.3 (LE 39) at 360 mg/kg, significantly ameliorated immunosuppression. This was evidenced by increased thymus and spleen indices (p<0.05 for LE 23; p<0.01 for LE 39), and improved total white blood cell and lymphocyte counts (p<0.05 for LE 23) compared with pathological controls. In vitro assays demonstrated a 10–20% enhancement of hPBMCs viability (up to ~30% for LE 23 at 200 µg/mL) without significant cytotoxicity. Conclusion: Selected Vietnamese Ganoderma species possess potential immunomodulatory activity and serve as promising candidates for pharmacological investigations. This study provides a systematic screening of indigenous Ganoderma species in Vietnam, though further studies must identify active constituents and underlying mechanisms.