Tacca chantrieri (Andre) Crude Extract Promoted Immunity in the Elderly (Ex-Vivo), and Inhibited Pathogenic and Opportunistic Bacteria

Abstract

Background: Tacca chantrieri (Andre), or the black bat flower, is commonly found in Southeast Asia; however, its effects on immunity have not been studied. This study aimed to investigate the effects of T. chantrieri crude extract on CD4+ T cell phenotypes and on the phagocytosis and oxidative burst of polymorphonuclear neutrophils (PMNs) in the elderly (ex-vivo). Its ability to inhibit opportunistic and pathogenic bacteria was also evaluated. Methods: T chantrieri crude extract was obtained by ethanolic extraction. A total of eight elderly (age ≥65 years) were enrolled in the study. Investigations used flow cytometric analysis. Antimicrobial effects were explored by agar well diffusion and minimum inhibition concentration (MIC) testing. Results: CD4+ T cell proportion significantly decreased at the 100 μg/ml concentration (p = 0.015). CD4+NKG2D+ T cells decreased at all concentrations (50, 100, 200, 300 μg/ml). Regarding PMNs, phagocytosis and oxidative burst in the treated group were significantly increased at 15 min compared with the untreated group (p = 0.039 and 0.015, respectively). Regarding antimicrobial effect, 100 mg/ml crude extract inhibited Staphylococcus epidermidis, Staphylococcus aureus, Neisseria sicca, and Acinetobacter lwoffii. MIC values were 1.23, 3.70, 33.33, and 100 mg/ml, respectively. Conclusions: This work reports preliminary findings of immunity promotion in the elderly following treatment with T. chantrieri crude extract. In future, the extract may be developed into a natural herb product or a form of alternative medicine for immune status enhancement, as well as a potential antimicrobial agent, particularly in the elderly.