MATERIALS AND METHODS: Methanol was used as the extraction solvent, 2,2 - diphenyl-1-picrylhydrazil (DPPH) for free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic compounds were measured using Total flavonoid, Phenolic acid and Polyphenols content assay to evaluate the quality of the antioxidant capacity of the rhizomes and vitamin C as positive control.
RESULTS: The results obtained revealed that Curcuma longa and Zingiber officinale had the highest free radical scavenging capacity of 270.07mg/TE/g DW and 266.95mg/TE/g DW and FRAP assay, Curcuma longa and Zingiber officinale also gave the highest ferric reducing power of 231.73mg/TE/g DW and 176.26mg/TE/g DW respectively. For Phenolic compounds, Curcuma longa and Curcuma xanthorrhiza gave the highest values of flavonoid (741.36mg/NGN/g DW and 220.53mg/NGN/g DW), phenolic acid (42.71mg/GAE/g DW and 22.03mg/GAE/g DW) and polyphenols (39.38mg/GAE/g DW and 38.01mg/GAE/g DW) respectively. Significant and positive linear correlations were found between Total antioxidant capacity and Phenolic compounds (R = 0.65 - 0.96).
CONCLUSION: This study provides evidence that extracts of Zingiberaceae (Ginger) rhizomes are a potential source of natural antioxidants and could serve as basis for future drugs and food supplements.
METHODS: The extract was analyzed quantitatively by performing a validated reversed phase high performance liquid chromatography (RP-HPLC). Zerumbone was isolated by chromatographic technique while the essential oil was acquired through hydro-distillation of the rhizomes and further analyzed by gas chromatography (GC) and GC-MS. Chemotaxis assay was assessed by using a 24-well cell migration assay kit, while CD18 integrin expression and phagocytic engulfment were measured using flow cytometry. The reactive oxygen species (ROS) production was evaluated by applying lucigenin- and luminol-enhanced chemiluminescence assays.
RESULTS: Zerumbone was found to be the most abundant compound in the extract (242.73 mg/g) and the oil (58.44%). Among the samples tested, the oil revealed the highest inhibition on cell migration with an IC50 value of 3.24 μg/mL. The extract, oil and zerumbone showed moderate inhibition of CD18 integrin expression in a dose-dependent trend. Z. zerumbet extract showed the highest inhibitory effect on phagocytic engulfment with percentage of phagocytizing cells of 55.43% for PMN. Zerumbone exhibited strong inhibitory activity on oxidative burst of zymosan- and PMA-stimulated neutrophils. Zerumbone remarkably inhibited extracellular ROS production in PMNs with an IC50 value of 17.36 μM which was comparable to that of aspirin.
CONCLUSION: The strong inhibition on the phagocytosis of neutrophils by Z. zerumbet extract and its essential oil might be due the presence of its chemical components particularly zerumbone which was capable of impeding phagocytosis at different stages.
METHODS: Essential oils obtained by steam distillation were analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the essential oils was evaluated against four bacteria: Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa); and two fungi: Candida albicans (C. albicans) and Cyptococcus neoformans (C. neoformans), using disc-diffusion and broth microdilution methods.
RESULTS: Cycloisolongifolene, 8,9-dehydro formyl (35.29%) and dihydrocostunolide (22.51%) were the major compounds in C. aeruginosa oil; whereas caryophyllene oxide (18.71%) and caryophyllene (12.69%) were the major compounds in C. mangga oil; and 2,6,9,9-tetramethyl-2,6,10-cycloundecatrien-1-one (60.77%) and α-caryophyllene (23.92%) were abundant in Z. cassumunar oil. The essential oils displayed varying degrees of antimicrobial activity against all tested microorganisms. C. mangga oil had the highest and most broad-spectrum activity by inhibiting all microorganisms tested, with C. neoformans being the most sensitive microorganism by having the lowest minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 0.1 μL/mL. C. aeruginosa oil showed mild antimicrobial activity, whereas Z. cassumunar had very low or weak activity against the tested microorganisms.
CONCLUSIONS: The preliminary results suggest promising antimicrobial properties of C. mangga and C. aeruginosa, which may be useful for food preservation, pharmaceutical treatment and natural therapies.