(E)-labda-8(17), 12-diene-15,16-dial has been isolated from the seeds of Alpinia nigra that is unsuitable for oral administration and evident from in silico studies. The present investigation therefore deals with understanding the effect of this compound on RBCs for intravenous administration. No prominent hemolytic effect of compound at a concentration of ≤0.4 mg/ml was found whereas higher concentrations perforated RBC membrane. The molecule showed remarkable inhibitory potential against Gram negative bacteria (concentration ≥0.025 mg/ml) causing cell lysis. In case of pathogenic yeast Candida albicans although growth was inhibited (concentration ≥ 0.0025 mg/ml), growth kinetic study revealed that the diterpene significantly delayed fungal growth (concentration 0.005-0.020 mg/ml) by preventing substrate uptake and was able to extend its lag phase in a dose-dependent manner. This study tries to unveil the mechanism of action of this diterpene on microorganisms with differential cell wall compositions.
Keywords: Alpinia nigra; Candida albicans; Gram negative bacteria; RBCs; labdane diterpene.