Natural products isolated from Tetragonula carbonaria cerumen modulate free radical-scavenging and 5-lipoxygenase activities in vitro

Abstract

BackgroundPropolis and cerumen are plant-derived products found in honeybees and stingless bees, respectively. Although propolis is an ancient folk medicine, the bioactivities of cerumen obtained from Australian native stingless bees (Tetragonula carbonaria) have not been widely studied. Therefore, we investigated selected anti-oxidant and anti-inflammatory properties of T. carbonaria cerumen.MethodsA methanolic extract was prepared from the combined cerumen of 40 T. carbonaria hives, and HPLC was used to screen for chemical constituents that scavenged 2,2-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The ability of cerumen extracts to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and to interfere with leukotriene B4 (LTB4) production in ionomycin-stimulated human neutrophils was also examined.ResultsThe extract dose-dependently scavenged DPPH (EC50 = 27.0 ± 2.3 μg/mL); and inhibited the 5-lipoxygenase (5-LOX)-mediated oxidation of linoleic acid (IC50 = 67.1 ± 9.6 μg/mL). Pre-treatment of isolated human neutrophils with the methanolic cerumen extract additionally inhibited the ionomycin-stimulated production of LTB4 from these cells (IC50 = 13.3 ± 5.3 μg/mL). Following multi-solvent extraction, the free radical-scavenging and 5-LOX-inhibiting activities of the initial cerumen extract were retained in a polar, methanol-water extract, which contained gallic acid and a range of flavonone and phenolic natural products.ConclusionsThe findings identify free radical scavenging activity, and interference by extracts of T. carbonaria cerumen in 5-LOX–LTB4 signaling. Further investigation is needed to determine whether the extracts will provide therapeutic benefits for medical conditions in which oxidative stress and inflammation are implicated, including cardiovascular disease and impaired wound healing.

Omega-3 fatty acids decrease oxidative stress and inflammation in macrophages from patients with small abdominal aortic aneurysm

“…The free radical-scavenging activities of 80 μM DHA, EPA and OA were examined using a colorimetric 1,1-diphenyl-2picrylhydrazyl (DPPH) assay as previously described 54 . Briefly, fatty acids and positive controls (BHT 227 μM; quercetin 50 μM) were incubated with methanolic DPPH solutions (100 μM; 30 min; 22 °C) and absorbance was measured at 518 nm.…”

Effect of Propolis mouthwash on clinical periodontal parameters in patients with gingivitis: A double‐blinded randomized clinical trial

“…The results showed that oral health indices such as the bleeding index and PI experienced greater improvement in the propolis group. Also, the frequency of teeth retaining their natural colour was significantly higher in the propolis group 22 . Kuo et al in their review study in 2018 reviewed five clinical trials regarding prevention of mucositis in patients undergoing chemotherapy by use of propolis and chlorhexidine mouthwashes.…”

“…Also, the frequency of teeth retaining their natural colour was significantly higher in the propolis group. 22 Kuo et al…”

Stingless Bee Propolis: New Insights for Anticancer Drugs

“…[ 54 ] demonstrated that propolis of the Australian species Tetragonula carbonaria inhibits the activity of the enzyme 5-lipoxygenase (5-LOX), which is known to catalyze the production of proinflammatory mediators. In addition, polar extracts of T. carbonaria propolis have been described to have antioxidant properties and to suppress production of the proinflammatory eicosanoid leukotriene B4 in human neutrophils stimulated with ionomycin [ 146 ].…”